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1

Composite flexible blanket insulation  

NASA Technical Reports Server (NTRS)

An improved composite flexible blanket insulation is presented comprising top silicon carbide having an interlock design, wherein the reflective shield is composed of single or double aluminized polyimide and wherein the polyimide film has a honeycomb pattern.

Kourtides, Demetrius A. (inventor); Lowe, David M. (inventor)

1994-01-01

2

Analysis and testing of multilayer and aerogel insulation configurations  

SciTech Connect

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.

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

3

Aerogel-based thermal insulation  

Microsoft Academic Search

Commercial development of aerogel granules, produced via ambient pressure processing, for advanced thermal insulation is discussed. By employing modeling and experimental verification, the thermal performance of granule compacts was studied. The application of a novel approach for surface modifying carbon black to the problem of adding opacifiers to silica aerogels is shown and improved thermal and mechanical properties were obtained.

Douglas M. Smith; Alok Maskara; Ulrich Boes

1998-01-01

4

Aerogel-Based Insulation for Industrial Steam Distribution Systems  

SciTech Connect

Thermal losses in industrial steam distribution systems account for 977 trillion Btu/year in the US, more than 1% of total domestic energy consumption. Aspen Aerogels worked with Department of Energy’s Industrial Technologies Program to specify, develop, scale-up, demonstrate, and deliver Pyrogel XT®, an aerogel-based pipe insulation, to market to reduce energy losses in industrial steam systems. The product developed has become Aspen’s best selling flexible aerogel blanket insulation and has led to over 60 new jobs. Additionally, this product has delivered more than ~0.7 TBTU of domestic energy savings to date, and could produce annual energy savings of 149 TBTU by 2030. Pyrogel XT’s commercial success has been driven by it’s 2-4X better thermal performance, improved durability, greater resistance to corrosion under insulation (CUI), and faster installation times than incumbent insulation materials.

John Williams

2011-03-30

5

Composite Flexible Blanket Insulation  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

6

Aerogel insulation systems for space launch applications  

Microsoft Academic Search

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

J. E. Fesmire

2006-01-01

7

Aerogel beads as cryogenic thermal insulation system  

NASA Astrophysics Data System (ADS)

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/m3) 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 10-5 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.

Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.

2002-05-01

8

Fibrous-Ceramic/Aerogel Composite Insulating Tiles  

NASA Technical Reports Server (NTRS)

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.

White, Susan M.; Rasky, Daniel J.

2004-01-01

9

Aerogel  

NSDL National Science Digital Library

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.

Network, Nanoscale I.; Industry, Oregon M.

2014-06-10

10

Aerogel Insulation Systems for Space Launch Applications  

NASA Technical Reports Server (NTRS)

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.

Fesmire, James E.

2005-01-01

11

Aerogel-Based Multilayer Insulation with Micrometeoroid Protection  

NASA Technical Reports Server (NTRS)

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.

Begag, Redouane; White, Shannon

2013-01-01

12

Thermal and Solar-Optical Properties of Silica Aerogel for Use in Insulated Windows.  

National Technical Information Service (NTIS)

Silica aerogel is a porous insulating material that is transport to solar radiation. To understand its insulating performance in a window system, it is necessary to first study component heat transfer paths. Aerogel's absorption coefficient, a measure of ...

J. Hartmann, M. Rubin, D. Arasteh

1987-01-01

13

Thin Thermal-Insulation Blankets for Very High Temperatures  

NASA Technical Reports Server (NTRS)

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.

Choi, Michael K.

2003-01-01

14

Low-Density, Aerogel-Filled Thermal-Insulation Tiles  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

15

Development of insulating coatings for liquid metal blankets  

SciTech Connect

It is shown that self-cooled liquid metal blankets are feasible only with electrically insulating coatings at the duct walls. The requirements on the insulation properties are estimated by simple analytical models. Candidate insulator materials are selected based on insulating properties and thermodynamic consideration. Different fabrication technologies for insulating coatings are described. The status of the knowledge on the most crucial feasibility issue, the degradation of the resisivity under irradiation, is reviewed.

Malang, S.; Borgstedt, H.U. [Kernforschungszentrum Karlsruhe GmbH (Germany); Farnum, E.H. [Los Alamos National Lab., NM (United States); Natesan, K. [Argonne National Lab., IL (United States); Vitkovski, I.V. [Efremov Inst., St. Petersburg (Russian Federation). MHD-Machines Lab.

1994-07-01

16

Aerogel-Based Insulation for High-Temperature Industrial Processes  

SciTech Connect

Under this program, Aspen Aerogels has developed an industrial insulation called Pyrogel HT, which is 4-5 times more thermally efficient than current non-aerogel technology. Derived from nanoporous silica aerogels, Pyrogel HT was specifically developed to address a high temperature capability gap not currently met with Aspen Aerogels{trademark} flagship product, Pyrogel XT. Pyrogel XT, which was originally developed on a separate DOE contract (DE-FG36-06GO16056), was primarily optimized for use in industrial steam processing systems, where application temperatures typically do not exceed 400 C. At the time, further improvements in thermal performance above 400 C could not be reasonably achieved for Pyrogel XT without significantly affecting other key material properties using the current technology. Cumulative sales of Pyrogel HT into domestic power plants should reach $125MM through 2030, eventually reaching about 10% of the total insulation market share in that space. Global energy savings would be expected to scale similarly. Over the same period, these sales would reduce domestic energy consumption by more than 65 TBtu. Upon branching out into all industrial processes in the 400 C-650 C regime, Pyrogel HT would reach annual sales levels of $150MM, with two-thirds of that being exported.

Dr. Owen Evans

2011-10-13

17

Thin Thermal-Insulation Blankets for Very High Temperatures  

NASA Technical Reports Server (NTRS)

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. A blanket according to the proposal (see figure) would be made of molybdenum, titanium nitride, and carbon- carbon composite mesh, which melt at temperatures of 2,610, 2,930, and 2,130 C, respectively. The emittance of molybdenum is 0.24, while that of titanium nitride is 0.03. Carbon-carbon composite mesh is a thermal insulator. Typically, the blanket would include 0.25-mil (.0.00635-mm)-thick hot-side and cold-side cover layers of molybdenum. Titanium nitride would be vapor-deposited on both surfaces of each cover layer. Between the cover layers there would be 10 inner layers of 0.15-mil (.0.0038-mm)-thick molybdenum with vapor-deposited titanium nitride on both sides of each layer. The thickness of each titanium nitride coat would be about 1,000 A. The cover and inner layers would be interspersed with 0.25-mil (0.00635-mm)-thick layers of carbon-carbon composite mesh. The blanket would have total thickness of 4.75 mils (approximately equal to 0.121 mm) and an areal mass density of 0.7 kilograms per square meter. One could, of course, increase the thermal- insulation capability of the blanket by increasing number of inner layers (thereby unavoidably increasing the total thickness and mass density).

Choi, Michael K.

2003-01-01

18

Thermal and solar-optical properties of silica aerogel for use in insulated windows  

Microsoft Academic Search

Silica aerogel is a porous insulating material that is transport to solar radiation. To understand its insulating performance in a window system, it is necessary to first study component heat transfer paths. Aerogel's absorption coefficient, a measure of the attenuation of radiation heat transfer, was determined over the spectral range 1-200 ..mu..m. Although radiation heat transfer is negligible over much

J. Hartmann; M. Rubin; D. Arasteh

1987-01-01

19

Aerogel: From Aerospace to Apparel  

NASA Technical Reports Server (NTRS)

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.

2001-01-01

20

Double layered tailorable advanced blanket insulation  

NASA Technical Reports Server (NTRS)

An advanced flexible reusable surface insulation material for future space shuttle flights was investigated. A conventional fly shuttle loom with special modifications to weave an integral double layer triangular core fabric from quartz yarn was used. Two types of insulating material were inserted into the cells of the fabric, and a procedure to accomplish this was developed. The program is follow up of a program in which single layer rectangular cell core fabrics are woven and a single type of insulating material was inserted into the cells.

Falstrup, D.

1983-01-01

21

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

22

A blanket design, apparatus, and fabrication techniques for the mass production of multilayer insulation blankets for the Superconducting Super Collider  

SciTech Connect

The multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) consists of full cryostat length assemblies of aluminized polyester film fabricated in the form of blankets and installed as blankets to the 4.5K cold mass and the 20K and 80K thermal radiation shields. Approximately 40,000 MLI blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator. Each blanket is nearly 17 meters long and 1.8 meters wide. This paper reports the blanket design, an apparatus, and the fabrication method used to mass produce pre-fabricated MLI blankets. Incorporated in the blanket design are techniques which automate quality control during installation of the MLI blankets in the SSC cryostat. The apparatus and blanket fabrication method insure consistency in the mass produced blankets by providing positive control of the dimensional parameters which contribute to the thermal performance of the MLI blanket. By virtue of the fabrication process, the MLI blankets have inherent features of dimensional stability three-dimensional uniformity, controlled layer density, layer-to-layer registration, interlayer cleanliness, and interlayer material to accommodate thermal contraction differences. 11 refs., 6 figs., 1 tab.

Gonczy, J.D.; Boroski, W.N.; Niemann, R.C.; Otavka, J.G.; Ruschman, M.K.; Schoo, C.J.

1989-09-01

23

"Flexible aerogel as a superior thermal insulation for high temperature superconductor cable applications"  

SciTech Connect

High temperature superconducting (HTS) cables are an advanced technology that can both strengthen and improve the national electrical distribution infrastructure. HTS cables require sufficient cooling to overcome inherent low temperature heat loading. Heat loads are minimized by the use of cryogenic envelopes or cryostats. Cryostats require improvement in efficiency, reliability, and cost reduction to meet the demanding needs of HTS conductors (1G and 2G wires). Aspen Aerogels has developed a compression resistant aerogel thermal insulation package to replace compression sensitive multi-layer insulation (MLI), the incumbent thermal insulation, in flexible cryostats for HTS cables. Oak Ridge National Laboratory tested a prototype aerogel package in a lab-scale pipe apparatus to measure the rate of heat invasion. The lab-scale pipe test results of the aerogel solution will be presented and directly compared to MLI. A compatibility assessment of the aerogel material with HTS system components will also be presented. The aerogel thermal insulation solution presented will meet the demanding needs of HTS cables.

White, Shannon O. [Aspen Aerogel, Inc.; Demko, Jonathan A [ORNL; Tomich, A. [Aspen Aerogel, Inc.

2010-01-01

24

Truss core sandwich panels with compacted aerogel insulation  

E-print Network

Silica aerogels are well known for their low thermal conductivity, approximately 15 mW/m-K. Their low relative density (typically less than 5%) reduces conduction through the solid and their small pore size, typically less ...

Chen, Kevin, S.M. Massachusetts Institute of Technology

2013-01-01

25

Silica aerogel granulate material for thermal insulation and daylighting  

Microsoft Academic Search

Silica aerogel granulate is a nanostructured material with high solar transmittance and low thermal conductivity. These properties offer exciting applications in building envelopes. One objective of the joint R&D project ISOTEG at ZAE Bayern was to develop and characterize a new glazing element based on granular silica aerogel. Heat transfer coefficients of less than 0.4W\\/(m2K) and a total solar energy

M. Reim; W. Körner; J. Manara; S. Korder; M. Arduini-Schuster; H.-P. Ebert; J. Fricke

2005-01-01

26

Foam/aerogel composite materials for thermal and acoustic insulation and cryogen storage  

NASA Technical Reports Server (NTRS)

The invention involves composite materials containing a polymer foam and an aerogel. The composite materials have improved thermal insulation ability, good acoustic insulation, and excellent physical mechanical properties. The composite materials can be used, for instance, for heat and acoustic insulation on aircraft, spacecraft, and maritime ships in place of currently used foam panels and other foam products. The materials of the invention can also be used in building construction with their combination of light weight, strength, elasticity, ability to be formed into desired shapes, and superior thermal and acoustic insulation power. The materials have also been found to have utility for storage of cryogens. A cryogenic liquid or gas, such as N.sub.2 or H.sub.2, adsorbs to the surfaces in aerogel particles. Thus, another embodiment of the invention provides a storage vessel for a cryogen.

Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Weiser, Erik S. (Inventor); Sass, Jared P. (Inventor)

2010-01-01

27

Foam/Aerogel Composite Materials for Thermal and Acoustic Insulation and Cryogen Storage  

NASA Technical Reports Server (NTRS)

The invention involves composite materials containing a polymer foam and an aerogel. The composite materials have improved thermal insulation ability, good acoustic insulation, and excellent physical mechanical properties. The composite materials can be used, for instance, for heat and acoustic insulation on aircraft, spacecraft, and maritime ships in place of currently used foam panels and other foam products. The materials of the invention can also be used in building construction with their combination of light weight, strength, elasticity, ability to be formed into desired shapes, and superior thermal and acoustic insulation power. The materials have also been found to have utility for storage of cryogens. A cryogenic liquid or gas, such as N.sub.2 or H.sub.2, adsorbs to the surfaces in aerogel particles. Thus, another embodiment of the invention provides a storage vessel for a cryogen.

Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Weiser, Erik S. (Inventor); Sass, Jared P. (Inventor)

2011-01-01

28

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

E-print Network

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 ...

Goutierre, Thomas

2011-01-01

29

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

30

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

NASA Astrophysics Data System (ADS)

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%.

Adelsberger, Kathleen

31

Thermal Performance of Composite Flexible Blanket Insulations for Hypersonic Aerospace Vehicles  

NASA Technical Reports Server (NTRS)

This paper describes the thermal performance of a Composite Flexible Blanket Insulation (C.F.B.I.) considered for potential use as a thermal protection system or thermal insulation for future hypersonic vehicles such as the National Aerospace Plane (N.A.S.P.). Thermophysical properties for these insulations were also measured including the thermal conductivity at various temperatures and pressures and the emissivity of the fabrics used in the flexible insulations. The thermal response of these materials subjected to aeroconvective heating from a plasma arc is also described. Materials tested included two surface variations of the insulations, and similar insulations coated with a Protective Ceramic Coating (P.C.C.). Surface and backface temperatures were measured in the flexible insulations and on Fibrous Refractory Composite Insulation (F.R.C.I.) used as a calibration model. The uncoated flexible insulations exhibited good thermal performance up to 35 W/sq cm. The use of a P.C.C. to protect these insulations at higher heating rates is described. The results from a computerized thermal analysis model describing thermal response of those materials subjected to the plasma arc conditions are included. Thermal and optical properties were determined including thermal conductivity for the rigid and flexible insulations and emissivity for the insulation fabrics. These properties were utilized to calculate the thermal performance of the rigid and flexible insulations at the maximum heating rate.

Kourtides, Demetrius A.

1993-01-01

32

Cryogenic Thermal Performance Testing of Bulk-Fill and Aerogel Insulation Materials  

NASA Astrophysics Data System (ADS)

Thermal conductivity testing under actual-use conditions is a key to understanding how cryogenic thermal insulation systems perform in regard to engineering, economics, and materials factors. The Cryogenics Test Laboratory at NASA's Kennedy Space Center tested a number of bulk-fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boiloff method were 78 K and 293 K. Tests were performed as a function of cold vacuum pressure under conditions ranging from high vacuum to no vacuum. Results were compared with those from complementary test methods in the range of 20 K to 300 K. Various testing techniques are required to completely understand the operating performance of a material and to provide data for answers to design engineering questions.

Scholtens, B. E.; Fesmire, J. E.; Sass, J. P.; Augustynowicz, S. D.; Heckle, K. W.

2008-03-01

33

Hybrid aerogel rigid ceramic fiber insulation and method of producing same  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

34

In situ production of spherical aerogel microparticles  

Microsoft Academic Search

Due to their high surface area, low density, open pore structure and excellent insulation properties aerogels are intensively investigated since the past decades for a diverse range of applications. The current methods of silica aerogel production by supercritical extraction produce monolithic aerogels, where the sol is aged in molds and dried by extraction with supercritical CO2. Aerogels in the form

M. Alnaief; I. Smirnova

2011-01-01

35

Advanced Aerogel Technology  

NASA Technical Reports Server (NTRS)

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.

Jones, Steven

2013-01-01

36

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

37

Aerogels for electronics  

SciTech Connect

In addition to their other exceptional properties, aerogels also exhibit unusual dielectric and electronic properties due to their nano-sized structures and high porosities. For example, aerogels have the lowest dielectric constants measured for a solid material (having values approaching 1.0); they have exceptionally high dielectric resistivities and strengths (i.e., ability to insulate very high voltages); they exhibit low dielectric loss at microwave frequencies; and some aerogels are electrically conductive and photoconductive. These properties are being exploited to provide the next generation of materials for energy storage, low power consumption, and ultra-fast electronics. We are working toward adapting these unusual materials for microelectronic applications, particularly, making thin aerogel films for dielectric substrates and for energy storage devices such as supercapacitors. Measurements are presented in this paper for the dielectric and electronic properties of aerogels, including the dielectric constant, loss factor, dielectric and electrical conductivity, volume resistivity, and dielectric strength. We also describe methods to form and characterize thin aerogel films which are being developed for numerous electronic applications. Finally, some of the electronic applications proposed for aerogels are presented. Commercialization of aerogels for electronics must await further feasibility, prototype development, and cost studies, but they are one of the key materials and are sure to have a major impact on future electronics.

Hrubesh, L.W.

1994-10-01

38

System and method for suppressing sublimation using opacified aerogel  

NASA Technical Reports Server (NTRS)

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.

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

39

Aerogel/polymer composite materials  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

40

Studying the Properties of Aerogel at MSFC  

NASA Technical Reports Server (NTRS)

Scientists at Marshall Space Flight Center (MSFC) have been studying the properties of Aerogel for several years. Aerogel, the lightest solid known to man, has displayed a high quality for insulation. Because of its smoky countenance, it has yet to be used as an insulation on windows, but has been used in the space program on the rover Sojourner, and has been used as insulation in the walls of houses and in automobile engine compartments. As heat is applied to Aerogel, scientist Dr. David Noever of Space Sciences Laboratory, Principal Investigator of Aerogel, studies for its properties trying to uncover the secret to making Aerogel a clear substance. Once found, Aerogel will be a major component in the future of glass insulation.

1997-01-01

41

The EU advanced lead lithium blanket concept using SiC f\\/SiC flow channel inserts as electrical and thermal insulators  

Microsoft Academic Search

Preparatory work on the EU advanced dual coolant (A-DC) blanket concept using SiCf\\/SiC flow channel inserts as electrical and thermal insulators has been carried out at the Forschungszentrum Karlsruhe in co-operation with CEA (SiCf\\/SiC composite-related issues) as a conceptual design proposal to the EU fusion power plant study planned to be launched in 2001 within the framework of the EU

P. Norajitra; L. Bühler; U. Fischer; K. Kleefeldt; S. Malang; G. Reimann; H. Schnauder; L. Giancarli; H. Golfier; Y. Poitevin; J. F. Salavy

2001-01-01

42

System and Method for Suppressing Sublimation using Opacified Aerogel.  

National Technical Information Service (NTIS)

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 constit...

J. A. Palk, J. G. Snyder, J. P. Fleurial, J. S. Sakamoto, S. M. Jones, T. Calliat

2004-01-01

43

Mechanical Properties of Aerogels  

NASA Technical Reports Server (NTRS)

Aerogels are extremely low density solids that are characterized by a high porosity and pore sizes on the order of nanometers. Their low thermal conductivity and sometimes transparent appearance make them desirable for applications such as insulation in cryogenic vessels and between double paned glass in solar architecture. An understanding of the mechanical properties of aerogels is necessary before aerogels can be used in load bearing applications. In the present study, the mechanical behavior of various types of fiber-reinforced silica aerogels was investigated with hardness, compression, tension and shear tests. Particular attention was paid to the effects of processing parameters, testing conditions, storage environment, and age on the aerogels' mechanical response. The results indicate that the addition of fibers to the aerogel matrix generally resulted in softer, weaker materials with smaller elastic moduli. Furthermore, the testing environment significantly affected compression results. Tests in ethanol show an appreciable amount of scatter, and are not consistent with results for tests in air. In fact, the compression specimens appeared to crack and begin to dissolve upon exposure to the ethanol solution. This is consistent with the inherent hydrophobic nature of these aerogels. In addition, the aging process affected the aerogels' mechanical behavior by increasing their compressive strength and elastic moduli while decreasing their strain at fracture. However, desiccation of the specimens did not appreciably affect the mechanical properties, even though it reduced the aerogel density by removing trapped moisture. Finally, tension and shear test results indicate that the shear strength of the aerogels exceeds the tensile strength. This is consistent with the response of brittle materials. Future work should concentrate on mechanical testing at cryogenic temperatures, and should involve more extensive tensile tests. Moreover, before the mechanical response of reinforced aerogels can be fully understood, more tests of unreinforced aerogels are necessary. Unreinforced aerogels are of particular use because their birefringent nature allows for visual determination of stress fields during mechanical testing. The success of any future tests depends on the availability of a large supply of quality specimens with well-documented preparation and storage histories.

Parmenter, Kelly E.; Milstein, Frederick

1995-01-01

44

Aerogels: stiff foams composed of up to 99.8% air Silica aerogel is the world's lowest-density solid: 1 mg/cm3  

E-print Network

#12;Aerogels: stiff foams composed of up to 99.8% air Silica aerogel is the world's lowest-density solid: 1 mg/cm3 Aerogels hold 15 different records for material properties, including best insulator 2.38 g piece of aerogel supports a 2.5 kg brick. #12;#12;#12;l = m Ã? n unit vector in orbital space

Fominov, Yakov

45

Protective Skins for Aerogel Monoliths  

NASA Technical Reports Server (NTRS)

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).

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

2007-01-01

46

Composite Aerogel Multifoil Protective Shielding  

NASA Technical Reports Server (NTRS)

New technologies are needed to survive the temperatures, radiation, and hypervelocity particles that exploration spacecraft encounter. Multilayer insulations (MLIs) have been used on many spacecraft as thermal insulation. Other materials and composites have been used as micrometeorite shielding or radiation shielding. However, no material composite has been developed and employed as a combined thermal insulation, micrometeorite, and radiation shielding. By replacing the scrims that have been used to separate the foil layers in MLIs with various aerogels, and by using a variety of different metal foils, the overall protective performance of MLIs can be greatly expanded to act as thermal insulation, radiation shielding, and hypervelocity particle shielding. Aerogels are highly porous, low-density solids that are produced by the gelation of metal alkoxides and supercritical drying. Aerogels have been flown in NASA missions as a hypervelocity particle capture medium (Stardust) and as thermal insulation (2003 MER). Composite aerogel multifoil protective shielding would be used to provide thermal insulation, while also shielding spacecraft or components from radiation and hypervelocity particle impacts. Multiple layers of foil separated by aerogel would act as a thermal barrier by preventing the transport of heat energy through the composite. The silica aerogel would act as a convective and conductive thermal barrier, while the titania powder and metal foils would absorb and reflect the radiative heat. It would also capture small hypervelocity particles, such as micrometeorites, since it would be a stuffed, multi-shock Whipple shield. The metal foil layers would slow and break up the impacting particles, while the aerogel layers would convert the kinetic energy of the particles to thermal and mechanical energy and stop the particles.

Jones, Steven M.

2013-01-01

47

Design Tool for Cryogenic Thermal Insulation Systems  

SciTech Connect

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.

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

48

Aerogel Composites: Strong and Waterproof  

NASA Technical Reports Server (NTRS)

Aerogels are exotic materials having superior thermal and physical properties with great potential for both space and industrial uses. Although aerogels are excellent low-density insulators with unique acoustic and optical properties, their commercialization potential is currently limited by moisture absorption, fragility, and cost. This paper describes useful, easily scaled-up solutions to the first two of these three problems. The waterproofing and water-repellent method described here is a cheaper and simpler improvement over previous permanent methods.

White, Susan; Hsu, Ming-ta; Arnold, James O. (Technical Monitor)

1999-01-01

49

Material Properties for Fiber-Reinforced Silica Aerogels  

NASA Technical Reports Server (NTRS)

Ceramic fiber-reinforced silica aerogels are novel materials for high performance insulation, including thermal protection materials. Experimental data are presented for the thermal and mechanical properties, showing the trends exhibited over a range of fiber loadings and silica aerogel densities. Test results are compared to that of unreinforced bulk aerogels.

White, Susan; Rouanet, Stephane; Moses, John; Arnold, James O. (Technical Monitor)

1994-01-01

50

Aerogels in Space-Based Applications  

NASA Technical Reports Server (NTRS)

Aerogel materials have two major space applications. Aerogels have already been used in Shuttle-based experiments to capture micrometeorites for earth-based investigation of the captured particles. To exploit the well-known low thermal conductivity of these materials, the use of aerogels for thermal insulation of spacecraft is under investigation. This paper will draw on published information about aerogels and other materials, and will include only noncritical technology. No discussion will be included of specific chemical processing techniques or of advanced, technologically critical concepts.

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

1994-01-01

51

Improved Silica Aerogel Composite Materials  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

52

Vinduer og solvaegge med monolitisk silica aerogel. (Windows and solar walls with monolithic solica aerogel).  

National Technical Information Service (NTIS)

This report deals with the experimental and theoretical work concerning application of evacuated monolithic silica aerogel as a transparent insulating material for window panes and covers for solar walls. Models for determination of the heat transfer thro...

K. Ingerslev Jensen

1991-01-01

53

Organic aerogel microspheres  

DOEpatents

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.

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

54

Organic aerogel microspheres  

DOEpatents

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.

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

1999-06-01

55

Aerogel commercialization pilot project. Final program report  

SciTech Connect

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.

NONE

1996-02-13

56

Aerogel Composites for Aerospace Thermal Protection  

NASA Technical Reports Server (NTRS)

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.

White, Susan

2003-01-01

57

Flexible aerogel composite for mechanical stability and process of fabrication  

DOEpatents

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.

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

1999-01-01

58

Flexible aerogel composite for mechanical stability and process of fabrication  

DOEpatents

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.

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

2000-01-01

59

Flexible aerogel composite for mechanical stability and process of fabrication  

SciTech Connect

A flexible aerogel and process of fabrication are disclosed. 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.

Coronado, P.R.; Poco, J.F.

2000-07-11

60

Prediction of mechanical properties of aerogels using a multifractal multidimensional multiscaling approach.  

E-print Network

??Aerogels, produced by sol-gel technologies, have several applications in sensors, high energyparticle physics, catalysis, heat insulation, supercapacitors, heat storage devices, highefficiency windows, among others. These… (more)

Campo Schickler, Fritz Andres.

2011-01-01

61

Nearly Seamless Vacuum-Insulated Boxes  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

62

Aerogel commercialization: Technology, markets and costs  

SciTech Connect

Commercialization of aerogels has been slow due to several factors including cost and manufacturability issues. The technology itself is well enough developed as a result of work over the past decade by an international-community of researchers. Several extensive substantial markets appear to exist for aerogels as thermal and sound insulators, if production costs can keep prices in line with competing established materials. The authors discuss here the elements which they have identified as key cost drivers, and they give a prognosis for the evolution of the technology leading to reduced cost aerogel production.

Carlson, G.; Lewis, D.; McKinley, K.; Richardson, J.; Tillotson, T.

1994-10-07

63

Shrinkage and pore structure in preparation of carbon aerogels  

Microsoft Academic Search

To aim at thermal insulator applications, the shrinkage and the pore structure of resorcinol–formaldehyde (RF) aerogels and\\u000a carbon aerogels were investigated during the supercritical drying and the carbonization process. The water (W) molar ratio\\u000a has small effects on the surface area or the particle size, but has significant effects on the density of the aerogel. Higher\\u000a W\\/R ratio leads to

Junzong FengJian; Jian Feng; Changrui Zhang

64

Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films  

E-print Network

Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films Moon-Ho Jo behavior in annealed SiO2 aerogel films for intermetal dielectric applications was investigated in a metal­insulator­semiconductor structure. SiO2 aerogel films with porosities of 70% exhibited Poole­Frenkel conduction both before

Jo, Moon-Ho

65

Particle Tracks in Aerogel  

NASA Technical Reports Server (NTRS)

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.

2005-01-01

66

Surface modified aerogel monoliths  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

67

Aerogel/Particle Composites for Thermoelectric Devices  

NASA Technical Reports Server (NTRS)

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).

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

2006-01-01

68

Sulfur-functionalized carbon aerogels: a new approach for loading high-surface-area electrode nanoarchitectures with precious metal catalysts  

Microsoft Academic Search

Thiophene-modified resorcinol–formaldehyde (RF) aerogels are prepared using a two-stage reaction sequence. Resorcinol–formaldehyde gels are generated in the first step using conventional sol–gel methods, followed by a second reaction stage in which the partially cured RF gel is reacted with 3-thiophenecarboxaldehyde before aerogel processing. Heterocyclic sulfur is retained in the aerogel following pyrolytic conversion of the insulating polymeric aerogel to its

Wendy S. Baker; Jeffrey W. Long; Rhonda M. Stroud; Debra R. Rolison

2004-01-01

69

Optimization of 4-Mercaptobenzoic Acid in SiO2Ag Colloid Aerogel Using Surface-Enhanced Raman Spectroscopy  

Microsoft Academic Search

Aerogels have been studied as potential insulating and conducting materials, but little research has been conducted characterizing organic molecules in aerogel matrices using surface-enhanced Raman spectroscopy (SERS). In this study, SiO2-Ag colloid aerogels were used as enhanced surfaces for SERS. SERS spectra of 4-mercaptobenzoic acid (4-MCBA) adsorbed to acid- and base-catalyzed SiO2-Ag colloid aerogels were obtained. It was observed that

Amy R. Cunningham

2012-01-01

70

Resorcinol-formaldehyde and carbon aerogel microspheres  

SciTech Connect

Aerogels are a unique class of materials possessing an open-cell structure with ultrafine cells/pores (<100nm), high surface area (400--1100 m{sup 2}/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10nm. Although monolithic aerogels are ideal candidates for many applications (e.g. transparent window insulation), current processing methods have limited their introduction into the commercial marketplace. Our research focuses on the formation of resorcinol-formaldehyde (RF) aerogel microspheres which offer an attractive alternative to monolith production. An inverse emulsion polymerization is used to produce these spherical gel particles which undergo solvent exchange followed by supercritical drying with carbon dioxide. This process yields aerogel microspheres (10--80{mu} diameter) which can be used as loosely packed powders, compression molded into near-net shapes using a polymer binder, or used as additives in conventional foaming operations to produce new aerogel composites with superior thermal properties. The emulsification procedure, thermal characterization, mechanical properties, and potential applications of RF aerogel microspheres will be discussed.

Alviso, C.T.; Pekela, R.W.; Gross, J. [Lawrence Livermore National Lab., CA (United States); Lu, X.; Caps, R.; Fricke, J [Wuerzburg Univ. (Germany). Physikalisches Inst.

1996-04-01

71

Thin aerogel films for optical, thermal, acoustic, and electronic applications  

SciTech Connect

Aerogels are a special class of continuously porous solid materials which are characterized by nanometer size particles and pores. Typically, aerogels are made using sol-gel chemistry to form a solvent filled, high porosity gel that is dried by removing the solvent without collapsing the tenuous solid phase. As bulk materials, aerogels are known to have many exceptional, and even some unique physical properties. Aerogels provide the highest thermal insulation and lowest dielectric constant of any other material known. However, some important applications require the aerogels in the form of thin films or sheets. For example, electronic applications require micrometer thin aerogel films bonded to a substrate, and others require thicker films, either on a substrate or as free standing sheets. Special methods are required to make aerogel thin films or sheets. In this paper, the authors discuss the special conditions needed to fabricate thin aerogel films and they describe methods to make films and thin sheets. They also give some specific applications for which aerogel films are being developed.

Hrubesh, L.W.; Poco, J.F. [Lawrence Livermore National Lab., CA (United States). Chemistry and Material Sciences Dept.

1994-09-01

72

High surface area aerogels for energy storage and efficiency  

NASA Astrophysics Data System (ADS)

The dissertation is divided into two main chapters, each focused on a different application for aerogel. The first chapter concerns the development of silica aerogel for thermal insulation. It begins with initial characterization of a silica aerogel insulation for a next-generation Advanced Radioisotope Stirling Generator for space vehicles. While the aerogel as made performs well, it is apparent that further improvements in mechanical strength and durability are necessary. The chapter then continues with the exploration of chlorotrimethysilane surface modification, which somewhat surprisingly provides a drastic increase in mechanical properties, allowing the inherently brittle silica network to deform plastically to >80% strain. It is hypothesized that the hydrophobic surface groups reduce capillary forces during drying, lowering the number of microcracks that may form and weaken the gel. This surface modification scheme is then implemented in a fiber-reinforced, opacified aerogel insulation for a prototypical thermoelectric generator for automotive waste heat recovery. This is the first known report of aerogel insulation for thermoelectrics. The aerogel insulation is able to increase the efficiency of the thermoelectric generator by 40% compared with commercial high-temperature insulating wool. Unfortunately, the supercritical drying process adds significant cost to the aerogel insulation, limiting its commercial viability. The chapter then culminates in the development and characterization of an Ambiently Dried Aerogel Insulation (ADAI) that eliminates the need for expensive supercritical drying. It is believed that this report represents the first aerogel insulation that can be dried without undergoing a large volume change before "springing back" to near its original volume, which allows it to be cast into place into complex geometries and around rigid inclusions. This reduces a large barrier to the commercial viability of aerogel insulation. The advantages of ADAI are demonstrated in a third-generation prototypical thermoelectric generator for automotive waste heat recovery. The second chapter then details two different aerogel-based materials for electrochemical energy storage. It begins with lithium titanate aerogel, which takes advantage of the high surface area of the aerogel morphology to display a batt-cap behavior. This should allow the lithium titanate aerogel to perform at higher rates than would normally be expected for the bulk oxide material. Additionally, the flexibility of the sol-gel process is demonstrated through the incorporation of electrically conductive high-surface area exfoliated graphite nanoplatelets in the oxide. The last section describes the characterization of a LiMn2O 4 spinel coated carbon nanofoam in a non-aqueous electrolyte. The short diffusion path, high surface area and intimately wired architecture of the nanofoam allows the oxide to retain its capacity at significantly higher rates when compared with literature values for the bulk oxide. Additionally, the nanometric length scale improves cycle life, and the high surface area dramatically increases the insertion capacity by providing a higher concentration of surface defects. Taken together, it is clear that aerogels are an extremely attractive class of material for applications pertaining to energy and efficiency, and further research in this area will provide valuable solutions for pressing societal needs. (Abstract shortened by UMI.).

Maloney, Ryan Patrick

73

Aerogel in Hand  

NASA Technical Reports Server (NTRS)

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.

2005-01-01

74

Distributing Radiant Heat in Insulation Tests  

NASA Technical Reports Server (NTRS)

Thermally radiating blanket of stepped thickness distributes heat over insulation sample during thermal vacuum testing. Woven of silicon carbide fibers, blanket spreads heat from quartz lamps evenly over insulation sample. Because of fewer blanket layers toward periphery of sample, more heat initially penetrates there for more uniform heat distribution.

Freitag, H. J.; Reyes, A. R.; Ammerman, M. C.

1986-01-01

75

Polyimide Aerogel Thin Films  

NASA Technical Reports Server (NTRS)

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.

Meador, Mary Ann; Guo, Haiquan

2012-01-01

76

Carbon nanomaterials in silica aerogel matrices  

SciTech Connect

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.

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

77

Clay Nanocomposite/Aerogel Sandwich Structures for Cryotanks  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

78

Progress on DCLL Blanket Concept  

SciTech Connect

Under the US Fusion Nuclear Science and Technology Development program, we have selected the Dual Coolant Lead Lithium concept (DCLL) as a reference blanket, which has the potential to be a high performance DEMO blanket design with a projected thermal efficiency of >40%. Reduced activation ferritic/martensitic (RAF/M) steel is used as the structural material. The self-cooled breeder PbLi is circulated for power conversion and for tritium breeding. A SiC-based flow channel insert (FCI) is used as a means for magnetohydrodynamic pressure drop reduction from the circulating liquid PbLi and as a thermal insulator to separate the high-temperature PbLi (~700°C) from the helium-cooled RAF/M steel structure. We are making progress on related R&D needs to address critical Fusion Nuclear Science and Facility (FNSF) and DEMO blanket development issues. When performing the function as the Interface Coordinator for the DCLL blanket concept, we had been developing the mechanical design and performing neutronics, structural and thermal hydraulics analyses of the DCLL TBM module. We had estimated the necessary ancillary equipment that will be needed at the ITER site and a detailed safety impact report has been prepared. This provided additional understanding of the DCLL blanket concept in preparation for the FNSF and DEMO. This paper will be a summary report on the progress of the DCLL TBM design and R&Ds for the DCLL blanket concept.

Wong, Clement; Abdou, M.; Katoh, Yutai; Kurtz, Richard J.; Lumsdaine, A.; Marriott, Edward P.; Merrill, Brad; Morley, Neil; Pint, Bruce A.; Sawan, M.; Smolentsev, S.; Williams, Brian; Willms, Scott; Youssef, M.

2013-09-01

79

Aerogel-supported filament  

DOEpatents

The present invention is a thin filament embedded in a low density aerogel for use in radiation detection instruments and incandescent lamps. The aerogel provides a supportive matrix that is thermally and electrically nonconductive, mechanically strong, highly porous, gas-permeable, and transparent to ionizing radiation over short distances. A low density, open-cell aerogel is cast around a fine filament or wire, which allows the wire to be positioned with little or no tension and keeps the wire in place in the event of breakage. The aerogel support reduces the stresses on the wire caused by vibrational, gravitational, electrical, and mechanical forces. 6 Figs.

Wuest, C.R.; Tillotson, T.M.; Johnson, C.V. III

1995-05-16

80

Aerogel-supported filament  

DOEpatents

The present invention is a thin filament embedded in a low density aerogel for use in radiation detection instruments and incandescent lamps. The aerogel provides a supportive matrix that is thermally and electrically nonconductive, mechanically strong, highly porous, gas-permeable, and transparent to ionizing radiation over short distances. A low density, open-cell aerogel is cast around a fine filament or wire, which allows the wire to be positioned with little or no tension and keeps the wire in place in the event of breakage. The aerogel support reduces the stresses on the wire caused by vibrational, gravitational, electrical, and mechanical forces.

Wuest, Craig R. (Danville, CA); Tillotson, Thomas M. (Tracy, CA); Johnson, III, Coleman V. (Dallas, TX)

1995-01-01

81

Carbon nanomaterials in silica aerogel matrices  

Microsoft Academic Search

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

Christopher E Hamilton; Manuel E Chavez; Juan G Duque; Gautam Gupta; Stephen K Doorn; Andrew M Dattelbaum; Kimberly A D Obrey

2010-01-01

82

Improved multilayer insulation applications. [spacecraft thermal control  

NASA Technical Reports Server (NTRS)

Multilayer insulation blankets used for the attenuation of radiant heat transfer in spacecraft are addressed. Typically, blanket effectiveness is degraded by heat leaks in the joints between adjacent blankets and by heat leaks caused by the blanket fastener system. An approach to blanket design based upon modular sub-blankets with distributed seams and upon an associated fastener system that practically eliminates the through-the-blanket conductive path is described. Test results are discussed providing confirmation of the approach. The specific case of the thermal control system for the optical assembly of the Space Telescope is examined.

Mikk, G.

1982-01-01

83

Blanket technology  

NASA Astrophysics Data System (ADS)

It was concluded that systems requirements would force a reassessment of the conventional approach to interconnecting cells into blanket or array modules. Defense applications (hardening) were identified as the key requirement that would force a movement away from the standard method (solder) of forming array circuits. The panel also agreed that requirements associated with the impending NASA Space Station and in-bound missions would lead to alternative interconnecting approaches. It was concluded that the diverse requirements of future space missions (high temperature and extended thermal cycling) might not be met by one approach, such as parallel-gap resistance welding. The panel suggested that other options such as high temperature solders and brazing be considered for the various mission requirements that were anticipated. The panel agreed that blanket technology was potentially suitable for in-orbit annealing to temperatures of 200 C provided that conventional soldered connecting techniques were replaced by "welding".

Scott-Monck, J.

84

Method of manufacturing aerogel composites  

DOEpatents

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.

Cao, W.; Hunt, A.J.

1999-03-09

85

Aerogel-clad optical fiber  

DOEpatents

An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency. 4 figs.

Sprehn, G.A.; Hrubesh, L.W.; Poco, J.F.; Sandler, P.H.

1997-11-04

86

Aerogel-clad optical fiber  

DOEpatents

An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency.

Sprehn, Gregory A. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Poco, John F. (Livermore, CA); Sandler, Pamela H. (San Marino, CA)

1997-01-01

87

Method of manufacturing aerogel composites  

DOEpatents

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.

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

1999-01-01

88

Aerogel waveplates Pradeep Bhupathi,1,*  

E-print Network

Aerogel waveplates Pradeep Bhupathi,1,* Jungseek Hwang,2, Rodica M. Martin,1 Jackson Blankstein,3% porosity silica aerogel samples under various degrees of uniaxial strain. Uniaxially compressed aerogels demonstrates that uniaxially strained high porosity aerogels can be used as tunable waveplates in a broad

Tanner, David B.

89

Probing the Geometry and Interconnectivity of Pores in Organic Aerogels Using Hyperpolarized 129Xe NMR Spectroscopy  

SciTech Connect

Aerogels represent a class of novel open-pore materials with high surface area and nanometer pore sizes. They exhibit extremely low mass densities, low thermal conductivity, good acoustic insulation, and low dielectric constants. These materials have potential applications in catalysis, advanced separation techniques, energy storage, environmental remediation, and as insulating materials. Organic aerogels are stiffer and stronger than silica aerogels and are better insulators with higher thermal resistance. Resorcinol-Formaldehyde (RF) aerogels are typically prepared through the base-catalyzed sol-gel polymerization of resorcinol with formaldehyde in aqueous solution to produce gels, which are then dried in supercritical CO2.1,2 The [resorcinol]/ [catalyst] (R/C) ratio of the starting sol-gel solution has been determined to be the dominant factor that affects the properties of RF aerogels. Since the unique microstructures of aerogels are responsible for their unusual properties, characterizing the detailed porous structures and correlating them with the processing parameters are vital to establish rational design principles for novel organic aerogels with tailored properties. In this communication we report the first use of hyperpolarized (HP) 129Xe NMR to probe the geometry and interconnectivity of pores in RF aerogels and to correlate these with synthetic conditions. Our work demonstrates that HP 129Xe NMR is so far the only method for accurately measuring the free volume-to-surface-area (Vg/S) ratios for soft mesoporous materials without using any geometric models.

Moudrakovski, Igor L.; Wang, Li Q.; Baumann, T.; Satcher, J. H.; Exarhos, Gregory J.; Ratcliffe, C. I.; Ripmeester, J. A.

2004-04-28

90

Cellulose aerogels from aqueous alkali hydroxide-urea solution.  

PubMed

Highly porous and strong cellulose aerogels were prepared by gelation of cellulose from aqueous alkali hydroxide/urea solution, followed by drying with supercritical CO2. Their morphology, pore structure, and physical properties were characterized by scanning and transmission electron microscopy, X-ray diffraction, nitrogen adsorption measurements, UV/Vis spectrometry, and tensile tests. The cellulose hydrogel was composed of interconnected about 20 nm wide. By using supercritical CO2 drying, the network structure in the hydrogel was well preserved in the aerogel. The results are preliminary but demonstrate the ability of this method to give cellulose aerogels of large surface areas (400-500 m2 g(-1)) which may be useful as adsorbents, heat/sound insulators, filters, catalyst supports, or carbon aerogel precursors. PMID:18605678

Cai, Jie; Kimura, Satoshi; Wada, Masahisa; Kuga, Shigenori; Zhang, Lina

2008-01-01

91

Edge-to-edge assembled graphene oxide aerogels with outstanding mechanical performance and superhigh chemical activity.  

PubMed

Aerogels, an extremely important aggregation state of various self-assembled nanoscale building blocks, have great potential in fields ranging from energy storage to thermal insulation. However, the porosity of aerogels makes them mechanically weak in most cases, and the chemical activity of the resulting aerogel needs consideration. Herein, chemically crosslinked graphene oxide (GO) 3D aerogels with large specific surface areas (up to 850 m(2) g(-1) ), outstanding mechanical performance (up to 20 MPa Young's modulus, 1 MPa yield strength and 45 J g(-1) specific energy adsorption), and superhigh chemical activity (toward some reducing gases such as H2 S, HI, and SO2 ), are fabricated by assembling 2D GO sheets edge-to-edge into uniform, 3D hydrogel networks with subsequent supercritical fluid drying. These aerogels are superior to other 3D frameworks (e.g. graphene aerogels) assembled via partial overlapping of the basal planes of the 2D building blocks. PMID:23512583

Huang, Huan; Chen, Pengwan; Zhang, Xuetong; Lu, Yun; Zhan, Wanchu

2013-04-22

92

Comet Ejecta in Aerogel  

NASA Technical Reports Server (NTRS)

[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.

2006-01-01

93

Chitin nanowhisker aerogels.  

PubMed

Chitin nanowhiskers are structured into mesoporous aerogels by using the same benign process used previously in our group to make cellulose nanowhisker aerogels. The nanowhiskers are sonicated in water to form a hydrogel before solvent-exchange with ethanol and drying under supercritical CO2 (scCO2 ). Aerogels are prepared with various densities and porosities, relating directly to the initial chitin nanowhisker content. scCO2 drying enables the mesoporous network structure to be retained as well as allowing the gel to retain its initial dimensions. The chitin aerogels have low densities (0.043-0.113?g?cm(-3) ), high porosities (up to 97?%), surface areas of up to 261?m(2) ?g(-1) , and mechanical properties at the high end of other reported values (modulus between 7 and 9.3?MPa). The aerogels were further characterized by using X-ray diffraction, BET analysis, electron microscopy, FTIR, and thermogravimetric analysis. Characterization showed that the rod-like crystalline nature of the nanowhiskers was retained during the aerogel production process, making the aerogel truly an assembled structure of chitin nanocrystals. These aerogels also showed the lowest reported shrinkage during drying to date, with an average shrinkage of only 4?%. PMID:23335426

Heath, Lindy; Zhu, Lifan; Thielemans, Wim

2013-03-01

94

Automotive Insulation  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

95

Two Dimensional Heat Transfer around Penetrations in Multilayer Insulation  

NASA Technical Reports Server (NTRS)

The objective of this task was to quantify thermal losses involving integrating MLI into real life situations. Testing specifically focused on the effects of penetrations (including structural attachments, electrical conduit/feedthroughs, and fluid lines) through MLI. While there have been attempts at quantifying these losses both analytically and experimentally, none have included a thorough investigation of the methods and materials that could be used in such applications. To attempt to quantify the excess heat load coming into the system due to the integration losses, a calorimeter was designed to study two dimensional heat transfer through penetrated MLI. The test matrix was designed to take as many variables into account as was possible with the limited test duration and system size. The parameters varied were the attachment mechanism, the buffer material (for buffer attachment mechanisms only), the thickness of the buffer, and the penetration material. The work done under this task is an attempt to measure the parasitic heat loads and affected insulation areas produced by system integration, to model the parasitic loads, and from the model produce engineering equations to allow for the determination of parasitic heat loads in future applications. The methods of integration investigated were no integration, using a buffer to thermally isolate the strut from the MLI, and temperature matching the MLI on the strut. Several materials were investigated as a buffer material including aerogel blankets, aerogel bead packages, cryolite, and even an evacuated vacuum space (in essence a no buffer condition).

Johnson, Wesley L.; Kelly, Andrew O.; Jumper, Kevin M.

2012-01-01

96

Cryogenic Insulation Systems  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

97

Method of patterning an aerogel  

DOEpatents

A method for producing a pattern in an aerogel disposed as a coating on a substrate comprises exposing the aerogel coating to the vapors of a hydrophobic silane compound, masking the aerogel coating with a shadow photomask and irradiating the aerogel coating with ultraviolet (UV) irradiation. The exposure to UV through the shadow mask creates a pattern of hydrophobic and hydrophilic regions in the aerogel coating. Etching away the hydrophilic regions of the aerogel coating, preferably with a 1 molar solution of sodium hydroxide, leaves the unwetted and unetched hydrophobic regions of the aerogel layer on the substrate, replicating the pattern of the photomask. The hydrophobic aerogel pattern can be further exposed to UV irradiation if desired, to create a hydrophilic aerogel pattern.

Reed, Scott T. (Edgewood, NM)

2012-07-24

98

Organic aerogel microspheres and fabrication method therefor  

DOEpatents

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.

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

99

Photon-Refracting Aerogel  

NASA Astrophysics Data System (ADS)

A threshold aerogel Cherenkov detector is being constructed at CUA to allow for the study of kaons in experiments at the Jefferson Laboratory. These subatomic particles move faster than light through the aerogel material, emitting Cherenkov radiation. Photomultiplier Tubes (PMTs) convert the photons from the Cherenkov radiation into electrons and multiply the electrons sufficiently to get a readable electronic signal, which can be analyzed. An important part of a threshold aerogel Cherenkov detector is its use of aerogel material of several refractive indices to cover the full dynamic range over which one wants to detect the particles of interest (in this case the kaon). Uniform coverage in refractive index is important as the location of the incoming particle will not be constant throughout the testing. In addition to testing for uniform coverage, we must also verify these refractive indices to ensure that the particles we are detecting are in fact kaons. The last test on the aerogel that needs to be performed is the measurement of transparency. Although aerogel is highly transparent, it is still necessary to find the amount of light being absorbed, reflected, or scattered versus how much will actually be measured by the PMTs used.

Rice, Daniel

2012-10-01

100

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

NASA Technical Reports Server (NTRS)

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).

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

2014-01-01

101

Gas permeability of carbon aerogels  

Microsoft Academic Search

Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 [degree]C. As a result of their interconnected porosity, ultrafine cell\\/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter

F. M. Kong; J. D. LeMay; S. S. Hulsey; C. T. Alviso; R. W. Pekala

1993-01-01

102

Thermal properties of advanced aerogel insulation  

E-print Network

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 ...

Cohen, Ellann

2011-01-01

103

21 CFR 182.1711 - Silica aerogel.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2009-04-01 true Silica aerogel. 182.1711 Section 182.1711 Food and...GRAS Food Substances § 182.1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica...

2010-04-01

104

21 CFR 582.1711 - Silica aerogel.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and...Purpose Food Additives § 582.1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica...

2010-04-01

105

Affordable Window Insulation with R-10\\/inch Rating  

Microsoft Academic Search

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

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

2004-01-01

106

The Evolution of Flexible Insulation as Thermal Protection Systems for Reusable Launch Vehicles: AFRSI (Advanced Flexible Reusable Surface Insulation) to CRI (Conformal Reusable Insulation)  

NASA Technical Reports Server (NTRS)

This viewgraph presentation gives an overview of the evolution of flexible insulation as a thermal protection system for reusable launch vehicles, Advanced Flexible Reusable Surface Insulation (AFRSI) to Conformal Reusable Insulation (CRI). Details are given on the approved use of AFRIS on the Shuttle Orbiter in June 1980, the first flight of AFRIS on STS-6, windward blanket development, composite flexible blanket insulation, and flight demonstrations.

Rezin, Marc; Oka, Kris; Arnold, Jim (Technical Monitor)

2001-01-01

107

Gas permeability of carbon aerogels  

SciTech Connect

Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 [degree]C. As a result of their interconnected porosity, ultrafine cell/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, the permeability of carbon aerogels was calculated from equations based upon Darcy's law. Our measurements show that carbon aerogels have permeabilities on the order of 10[sup [minus]12] to 10[sup [minus]10] cm[sup 2] over the density range from 0.05--0.44 g/cm[sup 3]. Like many other aerogel properties, the permeability of carbon aerogels follows a power law relationship with density, reflecting differences in the average mesopore size. Comparing the results from this study with the permeability of silica aerogels reported by other workers, we found that the permeability of aerogels is governed by a simple universal flow equation. This paper discusses the relationship between permeability, pore size, and density in carbon aerogels.

Kong, F.; LeMay, J.D.; Hulsey, S.S.; Alviso, C.T.; Pekala, R.W. (Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

1993-12-01

108

Fusion blanket high-temperature heat transfer  

SciTech Connect

Deep penetration of 14 MeV neutrons makes two-temperature region blankets feasible. A relatively low-temperature (approx. 300/sup 0/C) metallic structure is the vacuum/coolant pressure boundary, while the interior of the blanket, which is a simple packed bed of nonstructural material, operates at very high temperatures (>1000/sup 0/C). The water-cooled shell structure is thermally insulated from the steam-cooled interior. High-temperature steam can dramatically increase the efficiency of electric power generation, as well as produce hydrogen and oxygen-based synthetic fuels at high-efficiency.

Fillo, J.A.

1983-01-01

109

Aerogel Fingerprint Media  

SciTech Connect

A fingerprint medium which is made of an aerogel having a predetermined density. The fingerprint medium may have a midrange density for forming plates or may be crushed forming a powder. The fingerprint medium may further include at least one of a metal and metal oxide to enhance characteristics desirable in a fingerprint medium.

Miller, Fred S.; Andresen, Brian D.

1999-09-21

110

Composite Flexible Insulation for Thermal Protection of Space Vehicles.  

National Technical Information Service (NTIS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina ma...

D. A. Kourtides, H. K. Tran, S. A. Chiu

1992-01-01

111

Composite Flexible Insulation for Thermal Protection of Space Vehicles.  

National Technical Information Service (NTIS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina ma...

D. A. Kourtides, H. K. Tran, S. A. Chiu

1991-01-01

112

Materials for breeding blankets  

SciTech Connect

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.

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

1995-09-01

113

Aerogel nanocomposites for energy applications.  

E-print Network

??Efficient use of petroleum, coal and natural gas resources requires the use of novel materials and developing technologies. Aerogel-supported nanoparticles are materials with great potential… (more)

Li, Yuan, 1984-

2010-01-01

114

Metal Nanoparticle Aerogel Composites  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

115

Lightweight, Thermally Insulating Structural Panels  

NASA Technical Reports Server (NTRS)

Lightweight, thermally insulating panels that also serve as structural members developed. Honeycomb-core panel filled with low-thermal-conductivity, opacified silica aerogel preventing convection and minimizes internal radiation. Copper coating on face sheets reduces radiation. Overall thermal conductivities of panels smaller than state-of-art commercial non-structurally-supporting foam and fibrous insulations. On Earth, panels suitable for use in low-air-pressure environments in which lightweight, compact, structurally supporting insulation needed; for example, aboard high-altitude aircraft or in partially evacuated panels in refrigerators.

Eisen, Howard J.; Hickey, Gregory; Wen, Liang-Chi; Layman, William E.; Rainen, Richard A.; Birur, Gajanana C.

1996-01-01

116

Method for producing metal oxide aerogels having densities less than 0.02 g/cc  

DOEpatents

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.

Tillotson, Thomas M. (Tracy, CA); Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA); Thomas, Ian M. (Livermore, CA)

1994-01-01

117

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

DOEpatents

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.

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

1994-01-04

118

Acetic Acid Catalyzed Carbon Aerogels  

Microsoft Academic Search

We prepared carbon aerogels with a wide range of structural properties and densities using the weak acetic acid as a catalyst. Two series of acetic acid catalyzed carbon aerogels with different dilution of the catalyst and the monomers were investigated accurately. Structural investigation was performed via (U)SAXS, gas sorption and SEM. The pore and particle size can be tailored according

R. Brandt; R. Petricevic; H. Pröbstle; J. Fricke

2003-01-01

119

Production of hollow aerogel microspheres  

DOEpatents

A method is described for making hollow aerogel microspheres of 800-1200 .mu. diameter and 100-300 .mu. wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

Upadhye, Ravindra S. (Pleasanton, CA); Henning, Sten A. (Dalby, SE)

1993-01-01

120

Production of hollow aerogel microspheres  

SciTech Connect

A method is described for making hollow aerogel microspheres of 800--1200{mu} diameter and 100--300{mu} wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

Upadhye, R.S.; Henning, S.A.

1990-12-31

121

Enhancing mechanical properties of silica aerogels  

Microsoft Academic Search

Low-density monolithic silica and hexylene-bridged polysilsesquioxane aerogels were chemical vapor deposition (CVD) treated with hexamethyldisilazane or hexachlorodisilane silylating agents producing TMS (trimethylsilane) or Si layers on the aerogel. Reinforcing the weak aerogels by controlled deposition process improved their compressive strength and preserved their properties characteristic of low-density aerogels. When the silica and hexylene-bridged polysilsesquioxane aerogels were CVD treated with hexamethyldisilazane,

Kimberly A. D. Obrey; Kennard V. Wilson; Douglas A. Loy

2011-01-01

122

Apparent Thermal Conductivity Of Multilayer Insulation  

NASA Technical Reports Server (NTRS)

Mathematical model of apparent or effective thermal conductivity between two successive layers of multilayer thermal insulation (MLI) offers potential for optimizing performance of insulation. One gains understanding of how each physical mechanism contributes to overall flow of heat through MLI blanket. Model helps analyze engineering tradeoffs among such parameters as number of layers, thicknesses of gaps between layers, types of spacers placed in gaps, weight, overall thickness, and effects of foregoing on apparent thermal conductivity through blanket.

Mcintosh, Glen E.

1995-01-01

123

Flexible armored blanket development  

Microsoft Academic Search

An exploratory development contract was undertaken on December 23, 1977 which had as its purpose the development and demonstration of a flexible armored blanket design suitable for providing ballistic protection to nuclear weapons during shipment. Objectives were to design and fabricate a prototype blanket which will conform to the weapon shape, is troop-handleable in the field, and which, singly or

Roth

1978-01-01

124

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

E-print Network

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 ...

Salazar, Madeline

2013-01-01

125

Controllable fabrication of carbon aerogels  

Microsoft Academic Search

Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1, 3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 °C under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high

Ya'ning FENG; Lei MIAO; Sakae TANEMURA; Masaki TANEMURA; Kenzi SUZUKI

2006-01-01

126

Nanostructural engineering of organic aerogels  

SciTech Connect

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.

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

127

Blanket technology workshop report  

NASA Technical Reports Server (NTRS)

The solar array blanket, defined as a substrate covered with interconnected and glassed solar cells, but excluding the necessary support structure, deployment, and orientation devices is considered. The interactions between the blanket and the structure that is used to package, deploy, support and, if necessary restow it, are addressed along with systems constraints such as spacecraft configuration, size, and payload requirements. The influence on blanket design is emphasized. The three main mission classes considered are low Earth orbital (LEO), intermediate, or LEO to GEO transfer, and geosynchronous (GEO). Although interplanetary missions could be considered to be a separate class, their requirements, primarily power per unit mass, are generally close enough to geosynchronous missions to allow this mission class to be included within the third type. Examination of the critical elements of each class coupled with considerations of the shuttle capabilities is used to define the type of blanket technology most likely required to support missions that will be flown starting in 1990.

Scott-Monck, J. A.

1980-01-01

128

Measuring High Temperatures In Ceramic-Fiber Blankets  

NASA Technical Reports Server (NTRS)

Thermocouple assemblies devised specifically for measuring temperatures at fixed locations within insulating blankets made of such ceramic fibers as alumina, silicon carbide, and/or aluminoborosilicate. Thermocouples measure temperatures from 100 to 3,200 degrees F in oxidizing atmospheres. Wires enclosed in alumina sheath for protection against hot oxidation and mechanical damage.

Kourtides, Demetrius A.

1996-01-01

129

Physics of Interplanetary Dust Collection with Aerogel.  

National Technical Information Service (NTIS)

This report presents the results of research undertaken to study various problems associated with hypervelocity capture of dust particles in aerogel. The primary topics investigated were the properties of shocked aerogel and the requirements for reliable ...

W. W. Anderson

1998-01-01

130

Reflecting layers reduce weight of insulation  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

131

Aerogel composites and method of manufacture  

DOEpatents

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.

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

1999-01-01

132

Composition containing aerogel substrate loaded with tritium  

DOEpatents

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.

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

133

Recent progress in silica aerogel Cherenkov radiator  

E-print Network

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.

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

2012-01-01

134

Recent progress in silica aerogel Cherenkov radiator  

E-print Network

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.

Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Masato Kubo; Takeshi Sato

2012-03-19

135

Development of silica aerogel with any density  

Microsoft Academic Search

New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be

M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida

2005-01-01

136

Electrical Transport Properties of Carbon Aerogels  

Microsoft Academic Search

Carbon aerogels are prepared by sol-gel polymerization and supercriticle drying. By controlling the mass ratio of reactants and the molar ratio of resorcinol to catalyst (R\\/C), carbon aerogels with different microstructure can be developed. Hall effect is measured by Van der Bow method. The results show that the electrical conductivity increases with increasing density of carbon aerogel, and Hall mobility

J. Wang; S. Q. Zhang; J. Shen; Y. Z. Guo; S. M. Attia; B. Zhou; Z. Q. Lai; G. Z. Zheng; Y. S. Gui

2001-01-01

137

Carbon Aerogel Films Synthesized at Ambient Conditions  

Microsoft Academic Search

Carbon aerogels derived from organic sol-gel process and supercritical drying are novel porous materials with interconnect structures and higher electrical conductivity, which are considered to be ideal electrode materials for supercapacitors and rechargeable batteries. The objective of the research was to synthesize carbon aerogel films at ambient conditions. Resorcinol formaldehyde (RF) and carbon aerogel films have been produced with extremely

Jun Shen; Jue Wang; Jiwei Zhai; Yanzhi Guo; Guangming Wu; Bin Zhou; Xingyuan Ni

2004-01-01

138

Resorcinol-formaldehyde-derived carbon aerogel films  

Microsoft Academic Search

Carbon aerogels derived from organic sol-gel process and supercritical drying are novel porous materials with interconnect structures and higher electrical conductivity, which are considered to be ideal electrode materials for supercapacitors and rechargeable batteries. The objective of the research was to synthesize carbon aerogel films at ambient conditions. Resorcinol formaldehyde (RF) and carbon aerogel films have been produced with extremely

Jun Shen; Jue Wang; Yanzhi Guo; S. M. Attia; Bin Zhou

2000-01-01

139

Hydrophobic Silica Aerogels Strengthened with Nonwoven Fibers  

Microsoft Academic Search

Hydrophobic silica aerogels were prepared via a sol?gel process by surface modification at ambient pressure. Nonwoven fibers were distributed inside the silica aerogels as a composite to act as a supporting skeleton which increased the mechanical property of the silica aerogels. The morphology and pore structure of the composites were characterized by scanning electron microscopy (SEM) and N2 adsorption analyzer.

Zhihua Zhang; Jun Shen; Xingyuan Ni; Guangming Wu; Bin Zhou; Miaoxiang Yang; Xiaochun Gu; Mingjuan Qian; Yuehua Wu

2006-01-01

140

Investigation of the microwave absorbing properties of carbon aerogels  

Microsoft Academic Search

Carbon aerogel is a new kind of functional material. In this paper, carbon aerogel is prepared by solvent exchange instead of supercritical-drying. The catalyst concentration influences the microstructure of carbon aerogel greatly. By changing the resorcinol per catalyst (R\\/C) molar ratio, polymeric and colloidal carbon aerogel are formed. The absorbing properties of carbon aerogel are influenced by its microstructure and

S. Q. Zhang; C. G. Huang; Z. Y. Zhou; Z. Li

2002-01-01

141

Flexible nanofiber-reinforced aerogel (xerogel) synthesis, manufacture, and characterization.  

PubMed

Silica aerogels are sol-gel-derived materials consisting of interconnected nanoparticle building blocks that form an open and highly porous three-dimensional silica network. Flexible aerogel films could have wide applications in various thermal insulation systems. However, aerogel thin films produced with a pure sol-gel process have inherent disadvantages, such as high fragility and moisture sensitivity, that hinder wider applications of these materials. We have developed synthesis and manufacturing methods to incorporate electrospun polyurethane nanofibers into the cast sol film prior to gelation of the silica-based gel in order to reinforce the structure and overcome disadvantages such as high fragility and poor mechanical strength. In this method, a two-stage sol-gel process was employed: (1) acid-catalyzed tetraethyl orthosilicate hydrolysis and (2) base-catalyzed gelation. By precisely controlling the sol gelation kinetics with the amount of base present in the formulation, nanofibers were electrospun into the sol before the onset of the gelation process and uniformly embedded in the silica network. Nanofiber reinforcement did not alter the thermal conductivity and rendered the final composite film bendable and flexible. PMID:20356119

Li, Lichun; Yalcin, Baris; Nguyen, Baochau N; Meador, Mary Ann B; Cakmak, Miko

2009-11-01

142

Prediction of Mechanical Properties of Aerogels using a Multifractal Multidimensional Multiscaling Approach  

NASA Astrophysics Data System (ADS)

Aerogels, produced by sol-gel technologies, have several applications in sensors, high energy particle physics, catalysis, heat insulation, supercapacitors, heat storage devices, high efficiency windows, among others. These applications take advantage of the outstanding properties these materials present as a result of their structure. However, the low mechanical properties that these materials present as result of the process, limits their commercial applications. In this dissertation, it is investigated the relationship between the processing conditions and mechanical properties of these materials computationally. The prediction of the effective properties for these materials is a daunting task because of their complex structure. Aerogels's structure is not homogeneous nor periodic, but rather amorphous, nanostructured, and highly porous, making the traditional techniques used to study other materials inapplicable. This dissertation presents the prediction of mechanical properties of aerogels calculated by a novel Multifractal Multidimensional Multiscaling Approach (MMMA) developed here. MMMA consists on recursively calculating the effective properties of the material along several scales. Since aerogels and structures produced by sol-gel technologies present a multifractal character, it is shown that MMMA is applicable to predict the effective properties of these materials. The implementation of MMMA requires a fractal characterization of the structure. For this, computational scattering experiments were performed on structures resembling aerogels. The structures resembling aerogels were produced computationally incorporating the chemistry and the physical phenomena involved in the formation process. MMMA was used to predict the mechanical properties of silica aerogels for different processing conditions. Thus, mechanical properties, scattering experiments, and processing conditions were investigated and correlated in this work.

Campo Schickler, Fritz Andres

143

Reusable Surface Insulation  

NASA Technical Reports Server (NTRS)

Advanced Flexible Reusable Surface Insulation, developed by Ames Research Center, protects the Space Shuttle from the searing heat that engulfs it on reentry into the Earth's atmosphere. Initially integrated into the Space Shuttle by Rockwell International, production was transferred to Hi-Temp Insulation Inc. in 1974. Over the years, Hi-Temp has created many new technologies to meet the requirements of the Space Shuttle program. This expertise is also used commercially, including insulation blankets to cover aircrafts parts, fire barrier material to protect aircraft engine cowlings and aircraft rescue fire fighter suits. A Fire Protection Division has also been established, offering the first suit designed exclusively by and for aircraft rescue fire fighters. Hi-Temp is a supplier to the Los Angeles City Fire Department as well as other major U.S. civil and military fire departments.

1997-01-01

144

Extension Bulletin 1105: ln the Bank or Up the Chimney INSULATE YOUR AMODERATELY EASY  

E-print Network

Extension Bulletin 1105: ln the Bank or Up the Chimney INSULATE YOUR AMODERATELY EASY BASEMENTWALLS DO. IT-YOURSELF PROJECT Install 2" X3u studs along the walls to be insulated. Add glass fiber blanket insulation between the furring strips and finish with wallboard or panelling. NOTE: The method of insulation

145

Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage  

NASA Astrophysics Data System (ADS)

HIGHLY porous inorganic films have potential applications as dielectric materials, reflective and anti-reflective coatings, flat-panel displays, sensors, catalyst supports and super-insulating architectural glazings1-3. Aerogels4 are the most highly porous solids known, and can now be prepared from inorganic5 and organic6,7 precursors with volume-fraction porosities of up to 99.9% (ref. 8). Aerogels are normally prepared by supercritical extraction of the pore fluid from a wet gel1, which prevents the network collapse that is otherwise induced by capillary forces. But supercritical processing is expensive, hazardous and incompatible with the processing requirements of many potential applications,thus severely restricting the commercial exploitation of aerogels. Here we describe a means of preparing aerogels by a simple dip-coating method at ambient pressure without the need for supercriti-cal extraction. We add surface groups to the inorganic gel which make drying shrinkage reversible9: as the solvent is withdrawn, the gel springs back to a porous state. We can generate aerogel films with 98.5% porosity using this approach. We anticipate that it will greatly expand the commercial applications of these materials.

Prakash, Sai S.; Brinker, C. Jeffrey; Hurd, Alan J.; Rao, Sudeep M.

1995-03-01

146

Method for Nanoencapsulation of Aerogels and Nanoencapsulated Aerogels Produced by Such Method.  

National Technical Information Service (NTIS)

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 ...

T. A. Sullivan

2004-01-01

147

Method for Nanoencapsulation of Aerogels and Nanoencapsulated Aerogels Produced by such Method (2007).  

National Technical Information Service (NTIS)

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 ...

T. A. Sullivan

2007-01-01

148

Anisotropically structured magnetic aerogel monoliths  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

149

Tritiation of aerogel matrices: T2O, tritiated organics and tritium exchange on aerogel surfaces.  

National Technical Information Service (NTIS)

Three methods for incorporation of tritium into the phoshor/aerogel matrix have been demonstrated: (1) adsorption of T(sub 2)O by the aerogel, (2) incorporation of tritiated organic into the pores of the aerogel and (3) isotopic exchange of tritium from T...

R. E. Ellefson, J. T. Gill, T. J. Shepodd, L. E. Leonard

1990-01-01

150

Aerogels derived from multifunctional organic monomers  

SciTech Connect

Traditional inorganic aerogels are mad via the hydrolysis and condensation of metal alkoxides. Recently, we reported the synthesis of organic aerogels based upon the aqueous polycondensation of (1) resorcinol with formaldehyde and (2) melamine with formaldehyde. The former materials can also be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. In both the inorganic and organic systems, the structure and properties of the dried aerogel are dictated by polymerization conditions. Factors such as pH, reactant ratio, and temperature influence the crosslinking chemistry and growth processes taking place prior to gelation. The ability to tailor the structure and properties of aerogels at the nanometer scale opens up exciting possibilities for these novel materials. This paper addresses the chemistry-structure-property relationships of organic aerogels. 22 refs., 7 figs.

Pekala, R.W.; Alviso, C.T.; Kong, F.M.; Hulsey, S.S.

1991-09-01

151

Carbon Aerogels as Electrode Material in Supercapacitors  

Microsoft Academic Search

Due to their large specific surface area and their high electrical conductivity carbon aerogels are promising materials for electrodes in electrochemical double-layer capacitors (“supercapacitor”). The carbon aerogels were made via pyrolysis of resorcinol formaldehyde aerogels. The latter were prepared by supercritical and subcritical drying as well. The important findings of our investigation were, that the highest capacities of 46 F\\/cm3

U. Fischer; R. Saliger; V. Bock; R. Petricevic; J. Fricke

1997-01-01

152

Electron penetration of spacecraft thermal insulation  

NASA Technical Reports Server (NTRS)

The external thermal blanket with 13 mils of polyethylene which has the known range and stopping power as a function of electron energy is investiated. The most recent omnidirectional peak Jovian electron flux at 5 Jupiter radii is applied, the electron current penetrating the thermal blanket is calculated and allowed to impinge on a typical 20 mil polyethylene insulator surrounding a wire. The radiation dose rate to the insulator is then calculated and the electrical conductivity found. The results demonstrate that the increased electronic mobility is sufficient to keep the maximum induced electric field two orders of magnitude below the critical breakdown strength.

Powers, W. L.; Adams, B. F.; Inouye, G. T.

1981-01-01

153

Upflow Sludge Blanket Filtration  

Microsoft Academic Search

\\u000a The use of upflow sludge blanket filtration (USBF) covers the whole spectrum of chemical and biological treatment of water\\u000a using the agglomeration processes for transformation of colloidal and dissolved impurities in water into separable floc suspension.\\u000a The technical applications of USBF involve a wide range of treatment of underground and surface water for communal and industrial\\u000a use, and municipal, industrial,

Svatopluk Mackrle; Vladimír Mackrle; Old?ich Dra?ka

154

Deformation of Silica Aerogel During Fluid Adsorption  

E-print Network

Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.

Tobias Herman; James Day; John Beamish

2005-06-30

155

Reduction of the Casimir force using aerogels  

E-print Network

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.

R. Esquivel-Sirvent

2007-08-02

156

Reduction of the Casimir force using aerogels  

E-print Network

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.

Esquivel-Sirvent, R

2007-01-01

157

Improving the thermal performance of single-glazed windows using translucent granular aerogel  

Microsoft Academic Search

Cost-effective materials, products and installation methods are required to improve the energy efficiency of the UK's existing building stock. The aim of this paper is to assess the potential for high-performance translucent granular aerogel insulation to be retrofitted over single glazing to reduce heat loss without blocking out all of the useful natural light. In situ testing of a 10-mm-thick

Mark Dowson; David Harrison; Salmaan Craig; Zachary Gill

2011-01-01

158

Thermal insulation  

SciTech Connect

The presentation includes a discussion on the use of insulation and a review of information concerning insulation. Insulation technical conference and the Materials Research Program sponsored by eleven institutions are mentioned. Thermal performance of mineral fiber batts, the design density for loose-fill insulations, and insulated recessed light fixtures are discussed. Brief discussions are included on cellulosic and urea formaldehyde insulation and loading insulation by retrofit. An extensive reference list (28 citations) is presented. (MCW)

McElroy, D.L.

1980-01-01

159

Anisotropically structured magnetic aerogel monoliths.  

PubMed

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. PMID:25255203

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

2014-10-01

160

Thermal properties of carbon aerogels  

Microsoft Academic Search

The thermal diffusivity, a, of various carbon aerogel samples with different [resorcinol]\\/[catalyst] (RC) ratios and bulk densities was determined from room temperature to about 700°C. The temperature dependence of a could be described by the same equation for all samples. The thermal diffusivity was found to vary linearly with density. Thermal conductivity values were calculated using the heat capacity, cp(T),

V. Bock; O. Nilsson; J. Blumm; J. Fricke

1995-01-01

161

INFLUENCE OF CARBON AEROGEL TEXTURE ON PEMFC PERFORMANCES  

E-print Network

INFLUENCE OF CARBON AEROGEL TEXTURE ON PEMFC PERFORMANCES M. BRIGAUDET1, * , S. BERTHON-FABRY1 , C texture, carbon aerogels were used as catalyst supports in PEM fuel cell cathodes. Three carbon aerogels performances. By contrast, carbon aerogels present a controllable texture [1,2,3] and are thus suitable PEMFC

Boyer, Edmond

162

Carbon aerogel electrodes for direct energy conversion  

Microsoft Academic Search

A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to

Steven T. Mayer; James L. Kaschmitter; Richard W. Pekala

1997-01-01

163

Carbon aerogel electrodes for direct energy conversion  

Microsoft Academic Search

A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes is described, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and

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

1997-01-01

164

Polyurethane-based organic aerogels' thermal performance  

Microsoft Academic Search

A novel type of chemistry based on the use of polyisocyanates which can be turned into heavily cross-linked polyurethanes (PUR), polyureas, polyurethone imines or polyisocyanurates (PIR) to make organic aerogels is now being developed. Feasibility study of the polyisocyanate-based aerogels and various parameter effects on the thermal performance of these materials are described. This paper focuses on the low density

G. Biesmans; D. Randall; E. Francais; M. Perrut

1998-01-01

165

Chemical Analyses of Silicon Aerogel Samples  

E-print Network

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.

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

2008-01-01

166

Chemical Analyses of Silicon Aerogel Samples  

E-print Network

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.

I. van der Werf; F. Palmisano; R. De Leo; S. Marrone

2008-04-22

167

Insulation products promote thermal efficiency  

SciTech Connect

The judicious use of thermal insulation products in non-residential buildings can provide a number of advantages including increased energy efficiency, lower first costs (by avoiding overside HVAC systems), improved fire safety and better acoustics. Thermal insulation products are those products which retard the flow of heat energy. Materials include glass, plastics, and organic materials such as wood fibers, vermiculite and perlite. Forms range from the familiar batts and blankets of glass fibers to foamed plastic, rigid boards, losse fill and systems combining two or more products, such as polystyrene boards covered with insulating plaster. The R values of selected insulation materials with a cost/sq. ft. of each material at R 10 are given. Costs cover both the material and installation and may vary depending on local conditions.

Chalmers, R.

1985-04-01

168

Affordable Window Insulation with R-10/inch Rating  

SciTech Connect

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.

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

2004-10-15

169

Nanofibrillar chitin aerogels as renewable base catalysts.  

PubMed

We demonstrate the fabrication of chitin nanofibril aerogels and their successful application as base catalysts for the production of useful chemicals. Squid-pen chitin nanofibrils (ChNF) with primary C2-amine groups on their crystalline surfaces were fabricated into highly porous aerogels with high specific surface areas up to 289 m(2) g(-1) using freeze-drying or a supercritical drying process. The prepared ChNF aerogel was used in the aqueous Knoevenagel-condensation reaction and acted as a highly efficient base catalyst, suggesting that the combination of the nanofibrous aerogel structure and primary C2-amines exposed on the crystalline ChNF surface was effective for continuous flow catalysis. Because the ChNF aerogel can be easily prepared from abundant and renewable chitin present in nature, this strategy is a gateway to promoting and conducting green and sustainable chemistry. PMID:25285573

Tsutsumi, Yoshiyuki; Koga, Hirotaka; Qi, Zi-Dong; Saito, Tsuguyuki; Isogai, Akira

2014-11-10

170

Standard specification for glass fiber felt thermal insulation. ASTM standard  

SciTech Connect

This specification is under the jurisdiction of ASTM Committee C-16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.23 on Blanket and Loose Fill Insulation. Current edition approved Dec. 10, 1996. Published January 1997. Originally published as C 1086-87. Last previous edition was C 1086-90a.

Not Available

1997-01-01

171

High specific surface area aerogel cryoadsorber for vacuum pumping applications  

DOEpatents

A cryogenic pumping system is provided, comprising a vacuum environment, an aerogel sorbent formed from a carbon aerogel disposed within the vacuum environment, and cooling means for cooling the aerogel sorbent sufficiently to adsorb molecules from the vacuum environment onto the aerogel sorbent. Embodiments of the invention include a liquid refrigerant cryosorption pump, a compressed helium cryogenic pump, a cryopanel and a Meissner coil, each of which uses carbon aerogel as a sorbent material.

Hill, Randal M. (Livermore, CA); Fought, Eric R. (Brentwood, CA); Biltoft, Peter J. (Livermore, CA)

2000-01-01

172

MARS high-temperature blanket  

SciTech Connect

The MARS high temperature blanket is designed for the dual applications of either high efficiency electricity production or process heat for synthetic fuel production. Other blanket design goals are tritium self-sufficiency, low tritium inventory, more than 40% of the blanket energy extracted at high energy, long lifetime in the neutron environment, no use of reactive liquid metals, minimization of long term activation and use of characterized materials and fabrication techniques. This challenging set of goals has been met with a novel blanket design that uses radial zoning and the unique properties of the lead-lithium eutectic, Pb/sub 83/Li/sub 17/, as a coolant/neutron multiplier/breeder. During the first year of MARS, the blanket design was optimized for electricity production. A reoptimization for the synthetic fuel application is in progress.

Gordon, J.D.; Berwald, D.H.; Flanders, B.A.

1982-12-01

173

Synthesis and characterization of a nanocrystalline diamond aerogel  

PubMed Central

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. PMID:21555550

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, Joe H.

2011-01-01

174

Blanket comparison and selection study. Volume II  

SciTech Connect

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)

Not Available

1983-10-01

175

Waterproofing Nanostructured Aerogel-Ceramic Fiber Composites  

NASA Technical Reports Server (NTRS)

Aerogels are nanoporous materials which can be used to enhance the transport properties of ceramic fiber materials, to exploit their unique properties such as high porosity, large surface area, low density and low thermal conductivity. Numerous applications have been investigated. major obstacle to commercialization is that the structure of aerogels collapses due to the adsorption of water. simple and relatively cheap process has been developed to waterproof silica, alumina and alumina-silica and carbon aerogels and composites incorporating them. Previous waterproofing methods are short lived or expensive and time consuming.

White, Susan; Hsu, Ming Ta; Arnold, Jim (Technical Monitor)

2001-01-01

176

Hydrophobic silica aerogel production at KEK  

E-print Network

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.

Makoto Tabata; Ichiro Adachi; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa

2011-12-14

177

Band Formation during Gaseous Diffusion in Aerogels  

E-print Network

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.

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

1997-06-18

178

Measurement of muonium emission from silica aerogel  

E-print Network

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.

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

179

Hydrophobic silica aerogel production at KEK  

E-print Network

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.

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

2011-01-01

180

Measurement of muonium emission from silica aerogel  

E-print Network

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.

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

2013-06-17

181

Structure-property relationships of carbon aerogels  

SciTech Connect

Of the organic reactions in sol-gel polymerizations, the most studied reaction is the aqueous polycondensation of resorcinol with formaldehyde; the resulting crosslinked gels are supercritically dried from CO{sub 2} to give resorcinol-formaldehyde (RF) aerogels. These aerogels can be pyrolyzed to form vitreous carbon monoliths with black color, high porosity, ultrafine cell/pore size, high surface area, and interconnected particles of the organic precursor. The structure and properties of the carbon aerogels depend on R/C (resorcinol/catalyst) ratio of starting solution, pyrolysis temperature, and chemical activation. Each variable is discussed. Carbon aerogels provide an almost ideal electrode material (in double-layer capacitors) owing to low electrical resistivity (<40 mohm-cm), controllable pore size distribution (5--500 {angstrom}), and high volumetric surface areas ({approximately}500 m{sup 2}/cm{sup 3}).

Pekala, R.W.; Alviso, C.T.; Kong, F.M.

1993-12-01

182

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

E-print Network

lithium flow rate implies MHD insulator coating is not required. Task summary presented at the July 2000 propagation · POP MHD experiments · Structural analysis · Tritium · Configuration CAD · Power conversion #12 First Wall and Blanket Concept (Poloidal flow FW) QF [W/M2] TS TMAX R W(R) POROUS WALLS LIQUID LITHIUM

California at Los Angeles, University of

183

Accelerating the synthesis of carbon aerogel precursors  

Microsoft Academic Search

We have systematically modified the synthesis process for resorcinol and formaldehyde (RF) aerogels in order to reduce the time necessary for production of carbon aerogels. Firstly, the synthesis step that starts with mixing a solution of resorcinol and formaldehyde at relatively high resorcinol-to-catalyst, R\\/C, ratios (1000–3000) was modified by varying the gelation\\/aging temperature and time. Secondly, the progress of solvent

M. Wiener; G. Reichenauer; T. Scherb; J. Fricke

2004-01-01

184

Structure-property relationships of carbon aerogels  

Microsoft Academic Search

Of the organic reactions in sol-gel polymerizations, the most studied reaction is the aqueous polycondensation of resorcinol with formaldehyde; the resulting crosslinked gels are supercritically dried from COâ to give resorcinol-formaldehyde (RF) aerogels. These aerogels can be pyrolyzed to form vitreous carbon monoliths with black color, high porosity, ultrafine cell\\/pore size, high surface area, and interconnected particles of the organic

R. W. Pekala; C. T. Alviso; F. M. Kong

1993-01-01

185

Silica Aerogel Captures Cosmic Dust Intact  

NASA Technical Reports Server (NTRS)

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.

Tsou, P.

1994-01-01

186

Method for making monolithic metal oxide aerogels  

DOEpatents

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.

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

1995-03-07

187

Method for making monolithic metal oxide aerogels  

DOEpatents

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.

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

1995-01-01

188

Cytochrome C stabilization and immobilization in aerogels.  

PubMed

Sol-gel-derived aerogels are three-dimensional, nanoscale materials that combine large surface areas and high porosities. These traits make them useful for any rate-critical chemical process, particularly sensing or electrochemical applications, once physical or chemical moieties are incorporated into the gels to add their functionality into the ultraporous scaffold. Incorporating biomolecules into aerogels has been challenging due to the inability of most biomolecules to remain structurally intact within the gels during the necessary supercritical fluid processing. However, the heme protein cytochrome c (cyt. c) forms self-organized superstructures around gold (or silver) nanoparticles in buffer that can be encapsulated within silica and processed to form aerogels in which cyt. c retains its characteristic visible absorption. The gold (or silver) nanoparticle-nucleated superstructures protect the majority of the protein from the harsh physicochemical conditions necessary to form an aerogel. The Au?cyt. c superstructures exhibit rapid gas-phase recognition of nitric oxide (NO) within the aerogel matrix, as facilitated by the high-quality pore structure of the aerogel, and remain viable for weeks at room temperature. PMID:20865398

Harper-Leatherman, Amanda S; Wallace, Jean Marie; Rolison, Debra R

2011-01-01

189

Ambient pressure process for preparing aerogel thin films reliquified sols useful in preparing aerogel thin films  

DOEpatents

A method for preparing aerogel thin films by an ambient-pressure, continuous process. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.

Brinker, Charles Jeffrey (Albuquerque, NM); Prakash, Sai Sivasankaran (Minneapolis, MN)

1999-01-01

190

Ambient pressure process for preparing aerogel thin films reliquified sols useful in preparing aerogel thin films  

SciTech Connect

A method for preparing aerogel thin films by an ambient-pressure, continuous process is disclosed. The method of this invention obviates the use of an autoclave and is amenable to the formation of thin films by operations such as dip coating. The method is less energy intensive and less dangerous than conventional supercritical aerogel processing techniques.

Brinker, C.J.; Prakash, S.S.

1999-09-07

191

One pot synthesis of metal, carbides and polymeric aerogels .  

E-print Network

??"Ultra-low density, tlnee-dimensional assemblies of nanoparticles are referred to as aerogels, and typically are derived from supercritical fluid (SCF) drying of wet-gels. Aerogels are generally… (more)

Chandrasekaran, Naveen, 1983-

2011-01-01

192

Analysis of thermal performance of penetrated multi-layer insulation  

NASA Technical Reports Server (NTRS)

Results of research performed for the purpose of studying the sensitivity of multi-layer insulation blanket performance caused by penetrations through the blanket are presented. The work described in this paper presents the experimental data obtained from thermal vacuum tests of various penetration geometries similar to those present on the Hubble Space Telescope. The data obtained from these tests is presented in terms of electrical power required sensitivity factors referenced to a multi-layer blanket without a penetration. The results of these experiments indicate that a significant increase in electrical power is required to overcome the radiation heat losses in the vicinity of the penetrations.

Foster, Winfred A., Jr.; Jenkins, Rhonald M.; Yoo, Chai H.; Barrett, William E.

1988-01-01

193

Topological Insulators  

Microsoft Academic Search

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.

M. Z. Hasan; C. L. Kane

2010-01-01

194

Eureka! Aerogel capture of meteoroids in space  

NASA Technical Reports Server (NTRS)

Light gas gun studies have shown that 6 km/s solid mineral and glass test particles can be successively captured in 0.05 g cm(exp -3) aerogel without severe heating or fragmentation. In spite of this work, there has been uncertainty in the performance of aerogel for hypervelocity capture of real meteoroids. Natural impacts differ from simulations in that the particles are likely to be structurally weak and they typically impact at higher velocity that can be simulated in the laboratory. We are fortunate now to have had two successful capture experiments using aerogel exposed in space. These experiments provide fundamental data for the assessment of the value of silica aerogel for capture of hypervelocity meteoroids from spacecraft. The first experiment used 0.02 g cm(exp -3) aerogel flown on the lid of a Shuttle Get Away Special canister. During its 9 day exposure, the 0.165 m(exp 2) of aerogel in this Sample Return Experiment (SRE) captured two long 'carrot-shaped' tracks and one highly fractured bowl shaped 'crater'. The second collection was with 0.04 m(exp 2) of 0.05 g cm(exp -3) aerogel exposed on ESA's Eureca freeflying spacecraft that was exposed for 11 months before recovery by the Shuttle. The Eureca aerogel exposure consisted of four 10x10 cm module trays that were part of the TiCCE meteoroid collector built by the University of Kent at Canterbury. To date we have found ten 'carrot-shaped' tracks and two 'craters' on this experiment. The longest tracks in both exposures are over 2 mm long. Two of the TiCCE modules had a 0.1 micron Al film suspended a millimeter above the aerogel. On these modules several of the projectiles fragmented during passage through the film producing fields of carrot shaped tracks from the resulting miniature 'meteor' shower. Most of the tracks in these showers have observable particles at their ends. We have extracted one of the carrot track meteoroids and mounted it in epoxy for sectioning. So far the examination of these 14 impacts suggests that low density aerogel is a magic and highly effective media for intact capture of hypervelocity particles in space.

Brownlee, D. E.; Horz, F.; Hrubsch, L.; Mcdonnell, J. A. M.; Tsou, P.; Williams, J.

1994-01-01

195

Nanoporous phloroglucinol-formaldehyde carbon aerogels for electrochemical use  

Microsoft Academic Search

Phloroglucinol-Formaldehyde (PF) organic aerogels were prepared from alcoholic sol-gel polycondensation of phloroglucinol\\u000a with formaldehyde using KOH as base catalyst and followed by supercritical drying with carbon dioxide. Subsequent pyrolysis\\u000a of PF organic aerogel under He flow produced carbon aerogels. Textural properties of PF organic and carbon aerogels were obtained\\u000a by nitrogen adsorption-desorption, and their specific capacitances were measured by cyclic

Hyun-Joong Kim; Jin-Hong Kim; Won-Il Kim; Dong Jin Suh

2005-01-01

196

Assessment of alkali metal coolants for the ITER blanket  

SciTech Connect

The blanket system is one of the most important components of 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 Blanket Comparison and Selection Study, conducted earlier, described the overall comparative performance of different blanket concepts, including liquid metal, molten salt, water and helium. This paper will discuss the ITER requirements for a self-cooled blanket concept with liquid lithium and for indirectly cooled concepts that use other alkali metals such as NaK. The paper addresses the thermodynamics of interactions between the liquid metals (e.g., lithium and NaK) and structural materials (e.g., V-base alloys), together with associated corrosion/compatibility issues. Available experimental data are used to assess the long-term performance of the first wall in a liquid metal environment. Other key issues include development of electrical insulator coatings on the first-wall structural material to MHD pressure drop, and tritium permeation/inventory in self-cooled and indirectly cooled concepts. Acceptable types of coatings (based on their chemical compatibility and physical properties) are identified, and surface-modification avenues to achieve these coatings on the first wall are discussed. The assessment examines the extent of our knowledge on structural materials performance in liquid metals and identifies needed research and development in several of the areas in order to establish performance envelopes for the first wall in a liquid-metal environment.

Natesan, K.; Reed, C.B.; Mattas, R.F.

1994-06-01

197

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

SciTech Connect

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.

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

1993-07-01

198

Carbon Cloth Reinforced Carbon Aerogel Films Derived from Resorcinol Formaldehyde  

Microsoft Academic Search

Carbon cloth reinforced RF (Resorcinol Formaldehyde) aerogel films have been produced with extremely high RC ratio (molar ratio of resorcinol to catalyst) or with no catalyst at all. The gels were subcritically dried. Carbon aerogel films were obtained by pyrolysis of the RF aerogel films. The structure of the composite porous films was investigated using infrared spectrometer, optical and electron

J. Wang; M. Glora; R. Petricevic; R. Saliger; H. Proebstle; J. Fricke

2001-01-01

199

Aerogel composites for radioluminescent light\\/power sources  

Microsoft Academic Search

Aerogels are attractive matrices for phosphor particles for radioluminescent light and power applications. Unique aerogel properties such as transparency, high surface area and pore volume, low density, and tailorable surface chemistry provide advantages that allow much higher tritium loading than is currently available using existing technology. Additional research and development is needed to further improve the performance of the aerogel\\/phosphor

C. S. Askley; S. T. Reed; C. J. Brinker; R. J. Walko; R. E. Ellefson; J. T. Gill

1991-01-01

200

Silica aerogel: An intrinsically low dielectric constant material  

Microsoft Academic Search

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

Hrubesh

1995-01-01

201

DOI: 10.1002/adma.200601748 Carbon Nanotube Aerogels**  

E-print Network

DOI: 10.1002/adma.200601748 Carbon Nanotube Aerogels** By Mateusz B. Bryning, Daniel E. Milkie, Mohammad F. Islam, Lawrence A. Hough, James M. Kikkawa, and Arjun G. Yodh* Aerogels are ultralight, highly. Microscopically, aerogels are composed of tenuous networks of clustered nanoparticles, and the materials often

McGaughey, Alan

202

A threshold Cherenkov detector for K separation using silica aerogel  

E-print Network

A threshold Cherenkov detector for Kþ =pþ separation using silica aerogel R. Siudak a,b , A August 2008 Keywords: Threshold Cherenkov detector Silica aerogel Reaction pp ! Kþ ðLp� Kþ =pþ separation in the focal plane of a magnetic spectrograph. Silica aerogel with refractive index of n ¼ 1:05 is applied

Magiera, Andrzej

203

TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST  

E-print Network

TWO INTERSTELLAR DUST CANDIDATES FROM THE STARDUST AEROGEL INTERSTELLAR DUST COLLECTOR A. J, and is expected to have collected several dozen contemporary interstellar dust particles in aerogel and aluminum@home, we have so far identified 28 tracks in the aerogel collectors. We report on the results

Nittler, Larry R.

204

Elementary excitations of liquid 4 He in aerogel  

E-print Network

Elementary excitations of liquid 4 He in aerogel O. Plantevin and B. Fa°k Commissariat a` l-roton excitations of liquid 4 He immersed in aerogel of 95% porosity have been measured using inelastic neutron.25 K. Aerogel grown with deuterated materials not exposed to air was used and measure- ments in bulk

Glyde, Henry R.

205

Master Thesis Ring Imaging Cerenkov Counter with Aerogel  

E-print Network

[a4]report #12; i Master Thesis Ring Imaging Cerenkov Counter with Aerogel Radiator for HERMES;, k, p in all the HERMES engergy region: 2 GeV to 20 GeV. The new RICH system uses aerogel and C 4 F 10 gas as its Cerenkov radiator. The refractive index and other properties of all the aerogel tiles

206

Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999  

E-print Network

Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-1 CHAPTER 6: ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET Contributors Robert Woolley #12;Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-2 6. ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET 6

California at Los Angeles, University of

207

DATE: __________________________ NVLAP LAB CODE: _________________ NVLAP THERMAL INSULATION MATERIALS APPLICATION (REV. 2013-11-13) PAGE 1 OF 8  

E-print Network

: _________________ _________________________________________________________________________________________________________________ NVLAP THERMAL INSULATION MATERIALS APPLICATION (REV. 2013-11-13) PAGE 1 OF 8 Test Method Designation Short Title ______ 01/C01 ASTM C739 (Sec. 9) Cellulosic Fiber (Wood-Base) Loose-Fill Thermal Insulation-Fill) ______ 01/C03 ASTM C665 (Sec. 13.8) Mineral-Fiber Blanket Thermal Insulation for Light Frame Construction

208

Tritiation of aerogel matrices: T sub 2 O, tritiated organics and tritium exchange on aerogel surfaces  

SciTech Connect

Three methods for incorporation of tritium into the phoshor/aerogel matrix have been demonstrated: (1) adsorption of T{sub 2}O by the aerogel, (2) incorporation of tritiated organic into the pores of the aerogel and (3) isotopic exchange of tritium from T{sub 2} gas for the H residing on the surface of the aerogel. Adsorption of T{sub 2}O produces the brightest light (4.4 fL) to date but the tritium is loosely bound. Incorporation of tritiated organics into the pores of the aerogel produces less that theoretical luminance and intensity diminishes rapidly due to precipitation and darkening of the organic from radiation damage. Isotopic exchange produces a stable lamp by tritiating H sites on the surface of the aerogel. A lamp with stable luminance of 1.1 fL has been produced; a theoretical limit for a mono-layer coverage fo the aerogel surface is 2 to 3 fL. 7 refs., 4 figs., 2 tabs.

Ellefson, R.E.; Gill, J.T. (EG and G Mound Applied Technologies, Miamisburg, OH (USA)); Shepodd, T.J. (Sandia Labs., Livermore, CA (USA)); Leonard, L.E. (USDOE, Washington, DC (USA))

1990-01-01

209

Thermal performance measurements of a 100 percent polyester MLI (multilayer insulation) system for the Superconducting Super Collider  

SciTech Connect

The plastic materials used in the multilayer insulation (MLI) blankets of the superconducting magnets of the Superconducting Super Collider (SSC) are comprised entirely of polyesters. This paper reports on tests conducted in three separate experimental blanket arrangements. The tests explore the thermal performance of two candidate blanket joint configurations each employing a variation of a stepped-butted joint nested between sewn blanket seams. The results from the joint configurations are compared to measurements made describing the thermal performance of the basic blanket materials as tested in an ideal joint configuration. Twenty foil sensors were incorporated within each test blanket to measure interstitial layer and joint layer temperatures. Heat flux and thermal gradients are reported for high and degraded insulating vacuums, and during transient and steady state conditions. In complement with this paper is an associate paper bearing the same title head but with the title extension Part 1: Instrumentation and experimental preparation (300K-80K)'. 5 refs., 8 figs., 2 tabs.

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

1989-09-01

210

Volatiles in interplanetary dust particles and aerogels  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

211

Water extractable arabinoxylan aerogels prepared by supercritical CO2 drying.  

PubMed

Water extractable arabinoxylan (WEAX) aerogels were prepared by extracting the solvent from the alcogels (WEAX hydrogels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. WEAX aerogels were characterized using scanning electron microscopy and adsorption and desorption nitrogen isotherms. The micrographs indicate a heterogeneous porous network structure in WEAX aerogel. Adsorption/desorption nitrogen isotherms of this material were type IV, which confirm that this material possess a mesoporous structure. WEAX aerogels rehydration capability was evaluated and the water absorption mechanism was determined. The WEAX aerogels water absorption mechanism was non-Fickian (n = 0.54). PMID:23673527

Marquez-Escalante, Jorge; Carvajal-Millan, Elizabeth; Miki-Yoshida, Mario; Alvarez-Contreras, Lorena; Toledo-Guillén, Alma Rosa; Lizardi-Mendoza, Jaime; Rascón-Chu, Agustín

2013-01-01

212

Fission reactor experiments for solid breeder blankets  

Microsoft Academic Search

The testing needs for solid breeder blanket development are different from those for liquid breeder blankets. In particular, a reasonable number of moderate volume test sites in a neutron environment are needed. Existing fission reactors are shown to be able to provide this environment with reasonable simulation of many important blanket conditions. Three major additional fission reactor tests are identified

P. J. Gierszewski; M. A. Abdou; R. Puigh

1986-01-01

213

Methanosaeta fibers in anaerobic migrating blanket reactors  

E-print Network

Methanosaeta fibers in anaerobic migrating blanket reactors L.T. Angenent,* D. Zheng,* S. Sung An anaerobic migrating blanket reactor (AMBR) was seeded with flocculent biomass from a digester and fed of operation, a mature granular blanket developed in the reactor. Moreover, fibers of approximately 1 cm long

Angenent, Lars T.

214

Slotted Polyimide-Aerogel-Filled-Waveguide Arrays  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

215

Cellulose Insulation  

NASA Technical Reports Server (NTRS)

Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

1980-01-01

216

Composite flexible insulation for thermal protection of space vehicles  

NASA Technical Reports Server (NTRS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the aeroassist space transfer vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1991-01-01

217

Directory of certified insulation material. Sorted by type and manufacturer  

SciTech Connect

Insulation materials that have been certified as complying with the regulations that became effective September 22, 1981 are identified in the directory. Six physical forms of insulation are covered: board; foil; foam and spray; blanket; loose fill; and water heater kits, duct, and pipe wrap. Information on the manufacturer and brand name; material, type, facings; primary use, usage exposure, vapor barrier; labeled product thickness, and labeled thermal performance is given. (MCW)

Not Available

1982-03-01

218

Methyltrimethoxysilane based flexible silica aerogels for oil absorption applications  

NASA Astrophysics Data System (ADS)

The experimental results on the synthesis of flexible and superhydrophobic silica aerogels using methyltrimethoxysilane (MTMS) precursor by a two-step (acid-base) sol-gel process followed by the supercritical drying are reported. The effects of various sol-gel parameters on the flexibility of the aerogels have been investigated. The aerogels of different densities were obtained by varying the molar ratio of MeOH/MTMS(S) from 14 to 35, with lower densities for larger S values. It has been observed that the Young's modulus (Y) decreased from 14.11 × 104 to 3.43×104 N/m2 with the decrease in the density of the aerogels from 100 to 40 kg/m3. Simultaneously, the aerogels are superhydrophobic with a contact angle as high as 169°. The superhydrophobic aerogels are thermally stable up to a temperature of 463 K, above which they become hydrophilic. The aerogels have been characterized by bulk density, percentage volume shrinkage, and porosity measurements. The microstructures of the aerogels have been studied using the transmission electron microscopy (TEM). The Young's modulus of the aerogels has been determined by an uniaxial compression test. The variation of physical properties of the aerogels has been explained by taking into consideration the hydrolysis, condensation reactions, the resulting colloidal clusters and their network formation.

Kavale, Mahendra S.; Mahadik, D. B.; Parale, V. G.; Rao, A. Venkateswara; Wagh, P. B.; Gupta, S. C.

2012-06-01

219

Carbon Aerogels for Hydrogen Storage  

SciTech Connect

This effort is focused on the design of new nanostructured carbon-based materials that meet the DOE 2010 targets for on-board vehicle hydrogen storage. Carbon aerogels (CAs) are a unique class of porous materials that possess a number of desirable structural features for the storage of hydrogen, including high surface areas (over 3000 m{sup 2}/g), continuous and tunable porosities, and variable densities. In addition, the flexibility associated with CA synthesis allows for the incorporation of modifiers or catalysts into the carbon matrix in order to alter hydrogen sorption enthalpies in these materials. Since the properties of the doped CAs can be systematically modified (i.e. amount/type of dopant, surface area, porosity), novel materials can be fabricated that exhibit enhanced hydrogen storage properties. We are using this approach to design new H{sub 2} sorbent materials that can storage appreciable amounts of hydrogen at room temperature through a process known as hydrogen spillover. The spillover process involves the dissociative chemisorption of molecular hydrogen on a supported metal catalyst surface (e.g. platinum or nickel), followed by the diffusion of atomic hydrogen onto the surface of the support material. Due to the enhanced interaction between atomic hydrogen and the carbon support, hydrogen can be stored in the support material at more reasonable operating temperatures. While the spillover process has been shown to increase the reversible hydrogen storage capacities at room temperature in metal-loaded carbon nanostructures, a number of issues still exist with this approach, including slow kinetics of H{sub 2} uptake and capacities ({approx} 1.2 wt% on carbon) below the DOE targets. The ability to tailor different structural aspects of the spillover system (i.e. the size/shape of the catalyst particle, the catalyst-support interface and the support morphology) should provide valuable mechanistic information regarding the critical aspects of the spillover process (i.e. kinetics of hydrogen dissociation, diffusion and recombination) and allow for optimization of these materials to meet the DOE targets for hydrogen storage. In a parallel effort, we are also designing CA materials as nanoporous scaffolds for metal hydride systems. Recent work by others has demonstrated that nanostructured metal hydrides show enhanced kinetics for reversible hydrogen storage relative to the bulk materials. This effect is diminished, however, after several hydriding/dehydriding cycles, as the material structure coarsens. Incorporation of the metal hydride into a porous scaffolding material can potentially limit coarsening and, therefore, preserve the enhanced kinetics and improved cycling behavior of the nanostructured metal hydride. Success implementation of this approach, however, requires the design of nanoporous solids with large accessible pore volumes (> 4 cm{sup 3}/g) to minimize the gravimetric and volumetric capacity penalties associated with the use of the scaffold. In addition, these scaffold materials should be capable of managing thermal changes associated with the cycling of the incorporated metal hydride. CAs are promising candidates for the design of such porous scaffolds due to the large pore volumes and tunable porosity of aerogel framework. This research is a joint effort with HRL Laboratories, a member of the DOE Metal Hydride Center of Excellence. LLNL's efforts have focused on the design of new CA materials that can meet the scaffolding requirements, while metal hydride incorporation into the scaffold and evaluation of the kinetics and cycling performance of these composites is performed at HRL.

Baumann, T F; Worsley, M; Satcher, J H

2008-08-11

220

Chemical Analyses of Silicon Aerogel Samples.  

National Technical Information Service (NTIS)

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 ha...

F. Palmisano, R. De Leo, S. Marrone, T. van der Werf

2008-01-01

221

Eureka Aerogel Capture of Meteoroids in Space.  

National Technical Information Service (NTIS)

Light gas gun studies have shown that 6 km/s solid mineral and glass test particles can be successively captured in 0.05 g cm(exp -3) aerogel without severe heating or fragmentation. In spite of this work, there has been uncertainty in the performance of ...

D. E. Brownlee, F. Horz, L. Hrubsch, J. A. M. Mcdonnell, P. Tsou

1994-01-01

222

View of a Cometary Impact Into Aerogel  

NASA Technical Reports Server (NTRS)

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.

2006-01-01

223

Analysis of MHD Pressure Drop in the Packed Pebble Bed-Based Blanket for the Fds  

NASA Astrophysics Data System (ADS)

The Fusion-Driven Sub-critical System as a multifunctional hybrid reactor has been investigated in ASIPP. The liquid metal LiPb flow through a packed pebble bed-based blanket is considered to be one of the blanket candidates. In this contribution, the MHD pressure drop of liquid metal flow through the packed pebble bed has been calculated and analyzed under various conditions including (a) the size of the packed pebbles; (b) the ratio of occupied room by the packed pebbles to that of liquid metal; and (c) whether the pebbles surface is insulated or not Furthermore, asymptotic techniques to analyze large Hartmann parameter flow and interaction parameter flow are employed and an analytical model has been developed for the calculations of MHD pressure drop of liquid metal flow in a packed pebble bed. The appropriate method for calculating the MHD effects on the pressure drop through the packed pebble bed-based blanket for the FDS has been presented.

Wang, Hongyan; Wu, Yican; He, Xiaoxiong

2003-06-01

224

Processing and characterization of high porosity aerogel films  

SciTech Connect

Aerogels are highly porous solids having unique morphology among materials because both the pores and particles making up the material have sizes less than wavelengths of visible light. Such a unique morphology modifies the normal molecular transport mechanisms within the material, resulting in exceptional thermal, acoustical, mechanical, and electrical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. Special methods are required to make aerogel films with high porosity. In this paper, we discuss the special conditions needed to fabricate aerogel films having porosities greater than 75% and we describe methods of processing inorganic aerogel films having controllable thicknesses in the range 0.5 to 200 micrometers. We report methods and results of characterizing the films including thickness, refractive index, density (porosity), and dielectric constant. We also discuss results of metallization and patterning on the aerogel films for applications involving microminiature electronics and thermal detectors.

Hrubesh, L.W.; Poco, J.F.

1994-11-22

225

Metal-carbon aerogels as catalysts and catalyst supports  

Microsoft Academic Search

Several transition-metal-containing organic aerogels (Ti, Cr, Mo, W, Fe, Co and Ni) were obtained by polymerization of resorcinol and formaldehyde. The metal-carbon aerogels were obtained by pyrolysis of these aerogels in an inert atmosphere. The porous texture of the samples was characterized by different techniques (mercury porosimetry, He and Hg density and gas adsorption) as well as their surface chemistry

F. J. Maldonado-Hòdar; C. Moreno-Castilla; J. Rivera-Utrilla; M. A. Ferro-GarcIa

2000-01-01

226

Preparation of carbon aerogels from 5-methylresorcinol–formaldehyde gels  

Microsoft Academic Search

The systematics of the preparation of low density carbon aerogels from 5-methylresorcinol–formaldehyde (MR\\/F) organic aerogels dried in CO2 under supercritical conditions is reported. The synthesis of organic aerogels involves a doubly catalysed process: at first, in basic medium using a sodium carbonate catalyst and second, in acidic medium. The aquagels were obtained at room temperature within an hour. The carbonization

F. Pérez-Caballero; A.-L. Peikolainen; M. Uibu; R. Kuusik; O. Volobujeva; M. Koel

2008-01-01

227

Carbon aerogels for electric double-layer capacitors  

Microsoft Academic Search

In this study, carbon aerogels were derived via the pyrolysis of resorcinol-formaldehyde (RF) aerogels, which were cost-effectively manufactured from RF wet gels by an ambient drying technique instead of conventional supercritical drying. By varying the R\\/C ratio (molar ratio of resorcinol to catalyst), mesoporous carbon aerogels with high specific surface area were prepared successfully and further investigated as electrode materials

Lin ZHANG; Hongbo LIU; Ming WANG; Wei LIU

2006-01-01

228

Modification of carbon aerogel supports for PEMFC catalysts  

Microsoft Academic Search

Nitrogen enriched carbon aerogels and Co-based non-noble metal catalysts supported on carbon aerogels have been synthesized and tested using XPS, HRTEM, XRD and RDE techniques. XPS spectra of unmodified carbon aerogels indicated a presence of two oxygen O(1s) groups and five carbon C(1s) groups in deconvoluted spectra. XPS spectra of chemically modified samples indicated nitrogen N(1s) introduced in the carbon

A. Smirnova; T. Wender; D. Goberman; Yan-Ling Hu; M. Aindow; W. Rhine; N. M. Sammes

2009-01-01

229

Threshold aerogel Cherenkov counters of the KEDR detector  

NASA Astrophysics Data System (ADS)

Particle identification system based on aerogel threshold Cherenkov counters ASHIPH (Aerogel SHifter PHotomultiplier) was installed in the KEDR detector in 2013. The system consists of 160 counters arranged in two layers and contains 1000 liters of aerogel with refractive index of 1.05 and 160 MCP PMTs with multialkali photocathode. The efficiency of relativistic particles detection was measured. Long-term stability of ASHIPH counters was studied. The main reasons of efficiency degradation are presented.

Barnyakov, A. Yu; Barnyakov, M. Yu; Bobrovnikov, V. S.; Buzykaev, A. R.; Gulevich, V. V.; Danilyuk, A. F.; Katcin, A. A.; Kononov, S. A.; Kravchenko, E. A.; Kuyanov, I. A.; Onuchin, A. P.; Ovtin, I. V.; Rodyakin, V. A.

2014-09-01

230

Thermal Insulation  

NASA Technical Reports Server (NTRS)

Commercially known as Solimide, Temptronics, Inc.'s thermal insulation has application in such vehicles as aircraft, spacecraft and surface transportation systems (i.e. rapid transit cars, trains, buses, and ships) as acoustical treatment for door, wall, and ceiling panels, as a means of reducing vibrations, and as thermal insulation (also useful in industrial equipment). Product originated from research conducted by Johnson Space Center on advanced flame-resistant materials for minimizing fire hazard in the Shuttle and other flight vehicles.

1984-01-01

231

Optical and radiographical characterization of silica aerogel for Cherenkov radiator  

E-print Network

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.

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

2012-01-01

232

Optical and radiographical characterization of silica aerogel for Cherenkov radiator  

E-print Network

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.

Makoto Tabata; Ichiro Adachi; Yoshikiyo Hatakeyama; Hideyuki Kawai; Takeshi Morita; Keiko Nishikawa

2012-07-17

233

Packed fluidized bed blanket for fusion reactor  

DOEpatents

A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

Chi, John W. H. (Mt. Lebanon, PA)

1984-01-01

234

Toughened Thermal Blanket for MMOD Protection  

NASA Technical Reports Server (NTRS)

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.

Christiansen, Eric L.; Lear, Dana M.

2014-01-01

235

75 FR 11557 - Woven Electric Blankets From China  

Federal Register 2010, 2011, 2012, 2013

...accommodate either the electric blanket's wiring or a subassembly containing the electric blanket's wiring (e...the production of woven electric blankets. Although the...information concerning the conduct of this phase of the...

2010-03-11

236

Aerogel Keystones: Extraction Of Complete Hypervelocity Impact Events From Aerogel Collectors  

SciTech Connect

In January 2006, the Stardust mission will return the first samples from a solid solar-system body since Apollo, and the first samples of contemporary interstellar dust ever collected. Although sophisticated laboratory instruments exist for the analysis of Stardust samples, techniques for the recovery of particles and particle residues from aerogel collectors remain primitive. Here we describe our recent progress in developing techniques for extracting small volumes of aerogel, which we have called ''keystones,'' which completely contain particle impacts but minimize the damage to the surrounding aerogel collector. These keystones can be fixed to custom-designed micromachined silicon fixtures (so-called ''microforklifts''). In this configuration the samples are self-supporting, which can be advantageous in situations in which interference from a supporting substrate is undesirable. The keystones may also be extracted and placed onto a substrate without a fixture. We have also demonstrated the capability of homologously crushing these unmounted keystones for analysis techniques which demand flat samples.

Westphal, A J; Snead, C; Butterworth, A; Graham, G A; Bradley, J; Bajt, S; Grant, P G; Bench, G; Brennan, S; Piannetta, P

2003-11-07

237

Magnetic hydrophobic nanocomposites: Silica aerogel/maghemite  

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

238

Use of silica aerogels in Cherenkov counters  

Microsoft Academic Search

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

Yu. N. Kharzheev

2008-01-01

239

Subcritical crack growth in silica aerogel  

Microsoft Academic Search

The sub-critical crack growth domain in hydrophilic silica aerogel was studied using the Double-Cleavage-Drilled-Compression test (DCDC). The effect of temperature and water vapor content on the crack growth rate is measured. The experiments are carried out between 295 and 383 K with relative air moisture ranging from 5% to 80% Rh. Like dense silica, crack growth velocities were found to

F. Despetis; P. Etienne; S. Etiennecalas

2004-01-01

240

Effect of Cyclic Aeroconvective Heating on Flexible Thermal Insulations  

NASA Technical Reports Server (NTRS)

This paper describes the effect of cyclic aeroconvective heating on the thermal performance of ceramic flexible insulations considered for potential use as thermal protection systems or thermal insulations for future hypersonic vehicles such as the Reusable Launch Vehicles (RLV's) and other applications where structures require thermal protection from severe heating. The thermal response of these materials after exposure to cyclic aeroconvective heating from a plasma arc is described. The thermal insulations evaluated were Composite Flexible Blanket Insulations composed of an outer layer of aluminoborosilicate fabric and alumina insulation. The insulations were evaluated with and without a high emissivity coating. These insulations were exposed to the plasma arc stream for nine minutes reaching surface temperatures of 1150 C and a heat flux of 10.5 W/sq cm. Insulations were exposed three, six, or nine times in order to demonstrate reusability and to determine the effect oi coatings on the surface durability of these insulations. Test results demonstrated the capability of these insulations to protect either composite or metallic structures from high heating environments. It is shown that high emittance coatings reduce backface temperatures. The durability of these insulations when impacted at low velocities was also demonstrated. The interaction of the coatings with the ceramic fibers was characterized. An analytical thermal model was utilized to correlate experimental thermal test results with calculated values.

Kourtides, Demetrius A.; Zambrano, Brian; Kowalski, Tom; Rasky, Daniel J. (Technical Monitor)

1995-01-01

241

Structural Investigation of Resorcinol Formaldehyde and Carbon Aerogels Using SAXS and BET  

Microsoft Academic Search

The structure of organic RF aerogels (RF ? Recorcinol Formaldehyde) and carbon aerogels, their pyrolized counterparts, can be modified upon variation of the resorcinol to catalyst (RC) ratio. RF aerogels with RC ratios between 100 and 1500 have been produced in steps of 100. The densities for the organic aerogels were kept in the range of 350 to 390 kg

V. Bock; A. Emmerling; R. Saliger; J. Fricke

1997-01-01

242

Influence of monomer and catalyst concentration on RF and carbon aerogel structure  

Microsoft Academic Search

Structure and density of organic RF (resorcinol formaldehyde) aerogels and pyrolized RF aerogels (carbon aerogels) can be modified upon variation of the resorcinol to catalyst (RC) ratio and by varying the mass ratio of the reactants resorcinol and formaldehyde in the sol. Here, series of RF and carbon aerogels have been produced with RC 200, 500 and 1500, each covering

V. Bock; A. Emmerling; J. Fricke

1998-01-01

243

Structure and electrochemical properties of carbon aerogels synthesized at ambient temperatures as supercapacitors  

Microsoft Academic Search

In this paper, the carbon aerogels derived from organic sol–gel process were prepared by means of ambient drying technique. Morphology and physical properties of the carbon aerogels were characterized by scanning electron microscopy (SEM) and N2 sorption isotherm. It was found that the carbon aerogels were porous materials with pearly network structure, the particle size of carbon aerogels increased with

Jun Li; Xianyou Wang; Ying Wang; Qinghua Huang; Chunling Dai; Sergio Gamboa; P. J. Sebastian

2008-01-01

244

Strong orientational effect of stretched aerogel on the 3 He order parameter  

E-print Network

Strong orientational effect of stretched aerogel on the 3 He order parameter J. Elbs, Yu. M. Bunkov (Dated: February 18, 2013) Deformation of aerogel strongly modifies the orientation of the order parameter of superfluid 3 He confined in aerogel. We used a radial squeezing of aerogel to keep the orbital

Paris-Sud XI, Université de

245

The 'Fast Exchange' model visualized with 3 He confined in aerogel  

E-print Network

The 'Fast Exchange' model visualized with 3 He confined in aerogel: a Fermi liquid in contact in aerogel in the millikelvin temperature domain exemplifies a Fermi liquid in the presence of disorder aerogels, a renewal of the confined 3 He studies occured in the middle of the 90's [13, 14]. An aerogel

Paris-Sud XI, Université de

246

Structure and performance of carbon aerogel electrodes  

SciTech Connect

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.

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

1994-03-01

247

Cutting Silica Aerogel for Particle Extraction  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

248

Fission reactor experiments for solid breeder blankets  

Microsoft Academic Search

Solid breeder blanket testing needs have been characterized in the FINESSE study. These testing needs have unique characteristics, especially in comparison to liquid breeder blankets. First, there are a large number of potential breeder materials and material variables. Secondly, the influence of radiation on the primary uncertainties is large, but the influence of geometry is not. Finally, much of the

P. J. Gierszewski; R. Puigh; M. A. Abdou

1986-01-01

249

Ceramic pebble bed development for fusion blankets  

Microsoft Academic Search

Research on lithium ceramic breeders has been intensive since the late 1970s. The bulk material properties of several candidate lithium ceramics are essentially available, although there is still much work to be done on properties under irradiation and on the overall behavior in blanket modules. Based on these results, lithium ceramic breeder blankets have been selected in many fusion reactor

P Gierszewski; M. Dalle Donne; H Kawamura; M Tillack

1995-01-01

250

Physics studies for sodium cooled ATW blanket  

Microsoft Academic Search

Because the choice of blanket technologies is among the most important technical decisions faced in the Accel- erator Transmutation of Waste (ATW) program, extensive system studies have been pursued on blanket design. A wide range of potential transmuter configurations and fuel cycle scenarios have been investigated using sodium, lead-bismuth eutectic (LBE), and gas as coolant. The primary objective has been

R. N. Hill; H. S. Khalil

2001-01-01

251

Radiation Insulation  

NASA Technical Reports Server (NTRS)

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.

1995-01-01

252

Are Kondo insulators simply insulators?  

SciTech Connect

Since the discovery of the anomalous normal state properties of the high-T{sub c} oxides, there has been a lively debate concerning the applicability of conventional Fermi liquid theory to strongly interacting metals. A question arising naturally in this context is whether strongly interacting insulators exhibit properties at odds with ordinary band theory. Of course, Mott insulators, which in the absence of strong Coulomb interactions would be metals, represent the most dramatic breakdown of band theory. However, among strongly interacting insulators which one believes are band insulators, there have until recently been no indications that many-body effects yield observable consequences beyond those which band parameter renormalization might account for. The large number of recent theoretical papers on this renormalization for f-band materials, as well as the long struggle to achieve quantitative understanding of the band gap in as basic a semiconductor as Si, attest to the importance and difficulty of calculating renormalized band parameters for insulators. Also, the experience with Si clearly shows that the renormalization can depend on the quantity being measured. In a recent review, the authors placed the newly discovered Ce-based Kondo insulators, as well as older anomalous semiconductors such as SmB{sub 6} and FeSi, in the context of renormalized band theory. The conclusion was that in large measure, this theory represents an adequate starting point for understanding strongly correlated insulators. The goal here is not to repeat what was said before, but to focus on those aspects of charge and spin fluctuations which the band picture cannot obviously accomodate.

Aeppli, G.; DiTusa, J.F. [AT& T Bell Laboratories, Murray Hill, NJ (United States); Fisk, Z. [Los Alamos National Laboratory, NM (United States)

1994-12-31

253

Electrosorption of inorganic salts from aqueous solution using carbon aerogels.  

PubMed

Capacitive deionization (CDI) with carbon aerogels has been shown to remove various inorganic species from aqueous solutions, though no studies have shown the electrosorption behavior of multisolute systems in which ions compete for limited surface area. Several experiments were conducted to determine the ion removal capacity and selectivity of carbon aerogel electrodes, using both laboratory and natural waters. Although carbon aerogel electrodes have been treated as electrical double-layer capacitors, this study showed that ion sorption followed a Langmuir isotherm, indicating monolayer adsorption. The sorption capacity of carbon aerogel electrodes was approximately 1.0-2.0 x 10(-4) equiv/g aerogel, with ion selectivity being based on ionic hydrated radius. Monovalent ions (e.g., sodium) with smaller hydrated radii were preferentially removed from solution over multivalent ions (e.g., calcium) on a percent or molar basis. Because of the relatively small average pore size (4-9 nm) of the carbon aerogel material, only 14-42 m2/g aerogel surface area was available for ion sorption. Natural organic matter may foul the aerogel surface and limit CDI effectiveness in treating natural waters. PMID:12144279

Gabelich, Christopher J; Tran, Tri D; Suffet, I H Mel

2002-07-01

254

Carbon aerogel spheres prepared via alcohol supercritical drying  

Microsoft Academic Search

We have developed a method that would allow for the fabrication of carbon aerogel (CA) spheres. The inverse phase suspension polymerization of resorcinol and formaldehyde monomers with Na2CO3 as a catalyst followed by supercritical drying was explored. The effects of the chemical formulation and processing procedures and the conditions of the structures of organic and related carbon aerogels were studied.

Ning Liu; Shuting Zhang; Ruowen Fu; Mildred S. Dresselhaus; Gene Dresselhaus

2006-01-01

255

Aerogel and xerogel composites for use as carbon anodes  

DOEpatents

Disclosed herein are aerogel and xerogel composite materials suitable for use as anodes in fuel cells and batteries. Precursors to the aerogel and xerogel compounds are infused with inorganic polymeric materials or carbon particles and then gelled. The gels are then pyrolyzed to form composites with internal structural support.

Cooper, John F. (Oakland, CA); Tillotson, Thomas M. (Tracy, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

2008-08-12

256

Study of RICH Counter with Silica Aerogel Radiator  

Microsoft Academic Search

A proximity focusing RICH using aerogel as the Cherenkov radiator is being developed as a new particle identification device for the Belle detector upgrade. A prototype counter was constructed with recently produced aerogel samples, arranged in a focusing configuration, and a test beam experiment was carried out in order to evaluate the performance of the apparatus. With this device we

A. Kuratani; I. Adachi; K. Fujita; T. Fukushima; A. Gorisek; D. Hayashi; T. Iijima; K. Ikado; M. Iwabuchi; H. Kawai; S. Korpar; Y. Kozakai; P. Krizan; T. Matsumoto; Y. Mazuka; T. Nakagawa; S. Nishida; S. Ogawa; R. Pestotnik; T. Seki; T. Sumiyoshi; M. Tabata; Y. Unno

2006-01-01

257

A study of proximity focusing RICH with aerogel radiator  

Microsoft Academic Search

Proximity focusing RICH based on an aerogel Cherenkov radiator has been developed for a new particle identifier in the Belle upgrade. To further improve the detector performance, a new concept for Cherenkov ring imaging has been introduced, where multiple aerogel layers with different indices are accumulated to increase observed photoelectrons without making the single photon resolution worse. By constructing a

I. Adachi; K. Fujita; T. Fukushima; A. Gorisek; D. Hayashi; T. Iijima; T. Ikado; T. Ishikawa; H. Kawai; S. Korpar; Y. Kozakai; P. Krizan; A. Kuratani; Y. Mazuka; T. Nakagawa; S. Nishida; S. Ogawa; R. Pestotnik; T. Seki; T. Sumiyoshi; M. Tabata; Y. Unno

2007-01-01

258

Study of highly transparent silica aerogel as a RICH radiator  

Microsoft Academic Search

We have developed silica aerogel to be employed as a RICH radiator in the Belle PID upgrade. For this purpose, new aerogel sample with a higher refractive index (n) of ?1.05 was successfully produced while keeping the hydrophobic feature. In this novel technique, a new solvent was introduced in the first step of the sol–gel process so as to avoid

I. Adachi; S. Fratina; T. Fukushima; A. Gorisek; T. Iijima; H. Kawai; M. Konishi; S. Korpar; Y. Kozakai; P. Krizan; T. Matsumoto; Y. Mazuka; S. Nishida; S. Ogawa; S. Ohtake; R. Pestotnik; S. Saitoh; T. Seki; T. Sumiyoshi; M. Tabata; Y. Uchida; Y. Unno; S. Yamamoto

2005-01-01

259

Time Dependent Spectral Emission of Proton Bombarded Aerogels.  

National Technical Information Service (NTIS)

The University of Arizona 2 MV Van de Graaff accelerated 1 MeV protons to bombard aerogel targets. The spectroscopic emission characteristics of proton bombarded aerogels 1.68 mm - 5.50 mm thick were studied, particularly the emission as a function of bom...

E. W. Marsh

1998-01-01

260

Tailoring of morphology and surface properties of syndiotactic polystyrene aerogels.  

PubMed

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

Wang, Xiao; Jana, Sadhan C

2013-05-01

261

Wettability Alteration with Silica Aerogel Nano-Dispersion  

Microsoft Academic Search

This work studies the wettability alteration using nanoporous silica aerogels for enhanced oil recovery. Water wet flat glass and outcrop sandstone are used for this aim. Modified silica aerogels are synthesized with cheap water glass as the precursor, and ambient pressure drying method. Sessile drop method was used to measure the contact angles. Sandstones with 0° contact angle changed to

H. Bargozin; J. S. Moghaddas

2012-01-01

262

Fiducial Marks for Location of Particles in Aerogel  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

263

Highly porous ceramic oxide aerogels having improved flexibility  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

264

Blanket materials for DT fusion reactors  

SciTech Connect

This paper presents an overview of the critical materials issues that must be considered in the development of a tritium breeding blanket for a tokamak fusion reactor that operates on the D-T-Li fuel cycle. The primary requirements of the blanket system are identified and the important criteria that must be considered in the development of blanket technology are summarized. The candidate materials are listed for the different blanket components, e.g., breeder, coolant, structure and neutron multiplier. Three blanket concepts that appear to offer the most potential are: (1) liquid-metal breeder/coolant, (2) liquid-metal breeder/separate coolant, and (3) solid breeder/separate coolant. The major uncertainties associated with each of the design concepts are discussed and the key materials R and D requirements for each concept are identified.

Smith, D.L.

1981-01-01

265

sup 13 C NMR investigation of crosslinking in organic aerogels  

SciTech Connect

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.

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

1989-09-15

266

Insulation Material  

NASA Technical Reports Server (NTRS)

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.

1987-01-01

267

Radiation Insulation  

NASA Technical Reports Server (NTRS)

Radiation insulation technology from Apollo and subsequent spacecraft was used to develop superinsulators, used by makers of cold weather apparel, to make parkas, jackets, boots and outdoor gear such as sleeping bags. The radiant barrier technology offers warmth retention at minimal weight and bulk.

1987-01-01

268

Thermal alteration of hydrated minerals during hypervelocity capture to silica aerogel at the flyby speed of Stardust  

NASA Astrophysics Data System (ADS)

Outside the Earth's atmosphere, silica aerogel is one of the best materials to capture finegrained extraterrestrial particles in impacts at hypervelocities. Because silica aerogel is a superior insulator, captured grains are inevitably influenced by frictional heat. Therefore, we performed laboratory simulations of hypervelocity capture by using light-gas guns to impact into aerogels fine-grained powders of serpentine, cronstedtite, and Murchison CM2 meteorite. The samples were shot at >6 km s-1 similar to the flyby speed at comet P/Wild-2 in the Stardust mission. We investigated mineralogical changes of each captured particle by using synchrotron radiation X-ray diffraction (SR-XRD), transmission electron microscope (TEM), and field emission scanning electron microscope (FE-SEM). SR-XRD of each grain showed that the majority of the bulk grains keep their original mineralogy. In particular, SR-XRD and TEM investigations clearly exemplified the presence of tochilinite whose decomposition temperature is about 300 °C in the interior of the captured Murchison powder. However, TEM study of these grains also revealed that all the samples experienced melting and vesiculation on the surface. The cronstedtite and the Murchison meteorite powder show remarkable fracturing, disaggregation, melting, and vesiculation. Steep thermal gradients, about 2500 °C/?m were estimated near the surface of the grains (<2 ?m thick) by TEM observation. Our data suggests that the interior of >4 ?m across residual grains containing abundant materials that inhibit temperature rise would have not experienced >300 °C at the center.

Noguchi, Takaaki; Nakamura, Tomoki; Okudaira, Kyoko; Yano, Hajime; Sugita, Seiji; Burchell, Mark J.

2007-03-01

269

ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS  

SciTech Connect

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.

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

2002-04-01

270

Nano-sized Ni-doped carbon aerogel for supercapacitor.  

PubMed

Carbon aerogel was prepared by polycondensation of resorcinol with formaldehyde using sodium carbonate as a catalyst in ambient conditions. Nano-sized Ni-doped carbon aerogel was then prepared by a precipitation method in an ethanol solvent. In order to elucidate the effect of nickel content on electrochemical properties, Ni-doped carbon aerogels (21, 35, 60, and 82 wt%) were prepared and their performance for supercapacitor electrode was investigated. Electrochemical properties of Ni-doped carbon aerogel electrodes were measured by cyclic voltammetry at a scan rate of 10 mV/sec and charge/discharge test at constant current of 1 A/g in 6 M KOH electrolyte. Among the samples prepared, 35 wt% Ni-doped carbon aerogel (Ni/CA-35) showed the highest capacitance (110 F/g) and excellent charge/discharge behavior. The enhanced capacitance of Ni-doped carbon aerogel was attributed to the faradaic redox reactions of nano-sized nickel oxide. Moreover, Ni-doped carbon aerogel exhibited quite stable cyclability, indicating long-term electrochemical stability. PMID:22121750

Lee, Yoon Jae; Jung, Ji Chul; Park, Sunyoung; Seo, Jeong Gil; Baeck, Sung-Hyeon; Yoon, Jung Rag; Yi, Jongheop; Song, In Kyu

2011-07-01

271

Hypervelocity capture of meteoritic particles in nonsilica aerogels  

NASA Astrophysics Data System (ADS)

Abstract- The Stardust mission captured particles from the comet 81P/Wild 2 in gradient density silica aerogel and returned the collected samples to earth in 2006. The analyses of these particles have revealed several new insights into the formation of our solar system. However, since the aerogel used as the capture material was silica, the elemental analyses of the silica-rich particles were made more complicated in certain ways due to the mixing of the silicon of the particles and that of the aerogel. By using a nonsilica aerogel, future elemental analyses of silica-rich particles captured in aerogel could be made more straightforward. Resorcinol/formaldehyde (RF), alumina, and zirconia aerogels were impact tested with meteoritic fragments and the captured fragments were mapped with synchrotron-based X-ray microprobe (XRM) and the particles were analyzed with X-ray fluorescence (XRF). The resorcinol/formaldehyde aerogel proved to be the best capture material, in that it could be keystoned and XRF could be used to locate and analyze particles that were less than 10 ?m.

Jones, Steven M.; Flynn, George

2011-09-01

272

Synthesis and characterization of highly crystalline graphene aerogels.  

PubMed

Aerogels are used in a broad range of scientific and industrial applications due to their large surface areas, ultrafine pore sizes, and extremely low densities. Recently, a large number of reports have described graphene aerogels based on the reduction of graphene oxide (GO). Though these GO-based aerogels represent a considerable advance relative to traditional carbon aerogels, they remain significantly inferior to individual graphene sheets due to their poor crystallinity. Here, we report a straightforward method to synthesize highly crystalline GO-based graphene aerogels via high-temperature processing common in commercial graphite production. The crystallization of the graphene aerogels versus annealing temperature is characterized using Raman and X-ray absorption spectroscopy, X-ray diffraction, and electron microscopy. Nitrogen porosimetry shows that the highly crystalline graphene macrostructure maintains a high surface area and ultrafine pore size. Because of their enhanced crystallinity, these graphene aerogels exhibit a ?200 °C improvement in oxidation temperature and an order of magnitude increase in electrical conductivity. PMID:25283720

Worsley, Marcus A; Pham, Thang T; Yan, Aiming; Shin, Swanee J; Lee, Jonathan R I; Bagge-Hansen, Michael; Mickelson, William; Zettl, Alex

2014-10-28

273

Hypervelocity Capture of Meteoritic Particles in Nonsilica Aerogels  

SciTech Connect

The Stardust mission captured particles from the comet 81P/Wild 2 in gradient density silica aerogel and returned the collected samples to earth in 2006. The analyses of these particles have revealed several new insights into the formation of our solar system. However, since the aerogel used as the capture material was silica, the elemental analyses of the silica-rich particles were made more complicated in certain ways due to the mixing of the silicon of the particles and that of the aerogel. By using a nonsilica aerogel, future elemental analyses of silica-rich particles captured in aerogel could be made more straightforward. Resorcinol/formaldehyde (RF), alumina, and zirconia aerogels were impact tested with meteoritic fragments and the captured fragments were mapped with synchrotron-based X-ray microprobe (XRM) and the particles were analyzed with X-ray fluorescence (XRF). The resorcinol/formaldehyde aerogel proved to be the best capture material, in that it could be keystoned and XRF could be used to locate and analyze particles that were less than 10 {micro}m.

S Jones; G Flynn

2011-12-31

274

Flame Retardant Effect of Aerogel and Nanosilica on Engineered Polymers  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

275

Macroscopic fluctuations theory of aerogel dynamics  

E-print Network

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.

Lefevere, Raphael; Zambotti, Lorenzo

2010-01-01

276

Macroscopic fluctuations theory of aerogel dynamics  

E-print Network

We consider the thermodynamic potential describing the macroscopic fluctuation of the current and local energy of a general class of Hamiltonian models including aerogels. We argue that this potential is neither analytic nor strictly convex, a property that should be expected in general but missing from models studied in the literature. This opens the possibility of describing in terms of a thermodynamic potential non-equilibrium phase transitions in a concrete physical context. This special behaviour of the thermodynamic potential is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.

Raphael Lefevere; Mauro Mariani; Lorenzo Zambotti

2010-07-19

277

Insulating spacer for double insulated glass  

Microsoft Academic Search

An improved insulating spacer to reduce the heat transfer between the two panes of glass of double insulated glass comprises an extruded or roll-formed metal spacer together with plastic insulating elements which thermally isolate the metal spacer from the panes of glass while permitting conventional application of the sealant to provide reliable bonding. In one embodiment the plastic insulator comprises

1977-01-01

278

Adsorption of Helium in Silica Aerogel Near the Critical Point  

NASA Astrophysics Data System (ADS)

When fluids are adsorbed in small pores, capillary forces cause the pores to fill before bulk liquid appears, and isotherms usually show hysteresis between filling and emptying. The tenuous structure of aerogels provides a unique medium in which to study the effect of dilute impurities on liquid-vapor properties, particularly near the critical point where it may be possible to observe equilibrium behavior. We have used a capacitive technique to study adsorption in silica aerogel of two different densities near the liquid-vapor critical point of helium. We compare the disappearance of hysteresis in helium adsorption isotherms in different density aerogels to the behavior in vycor glass.

Herman, Tobias; Day, James; Beamish, John

2006-09-01

279

A Cherenkov Radiation Detector with High Density Aerogels  

E-print Network

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.

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

2009-01-01

280

Highly porous and mechanically strong ceramic oxide aerogels  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

281

Highly porous and mechanically strong ceramic oxide aerogels  

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

282

Nuclear aspects of molten salt blankets  

Microsoft Academic Search

Nuclear aspects of candidate molten salts, namely a mixture of LiF and BeF2 (FLIBE) and a mixture of LiF, NaF, and BeF2 (FLINABE), were investigated for application as blanket coolants in tokamak fusion power plants. Tritium breeding, blanket energy multiplication, and neutron transmutation of these salts were assessed. Neutron activation of FLIBE and FLINABE was evaluated and site-boundary dose due

E. T Cheng; B. J Merril; Dai-Kai Sze

2003-01-01

283

Silver Teflon blanket: LDEF tray C-08  

NASA Technical Reports Server (NTRS)

A study of the Teflon blanket surface at the edge of tray C-08 illustrates the complexity of the microenvironments on the Long Duration Exposure Facility (LDEF). The distribution of particulate contaminants varied dramatically over a distance of half a centimeter (quarter of an inch) near the edge of the blanket. The geometry and optical effects of the atomic oxygen erosion varied significantly over the few centimeters where the blanket folded over the edge of the tray resulting in a variety of orientations to the atomic oxygen flux. A very complex region of combined mechanical and atomic oxygen damage occurred where the blanket contacted the edge of the tray. A brown film deposit apparently fixed by ultraviolet light traveling by reflection through the Teflon film was conspicuous beyond the tray contract zone. Chemical and structural analysis of the surface of the brown film and beyond toward the protected edge of the blanket indicated some penetration of energetic atomic oxygen at least five millimeters past the blanket-tray contact interface.

Crutcher, E. Russ; Nishimura, L. S.; Warner, K. J.; Wascher, W. W.

1992-01-01

284

Temperature measurements of shocked silica aerogel foam  

NASA Astrophysics Data System (ADS)

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.

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

285

Multifunctional electroactive heteroatom-doped carbon aerogels.  

PubMed

The design and synthesis of highly active, durable, and cheap nanomaterials for various renewable energy storage and conversion applications is extremely desirable but remains challenging. Here, a green and efficient strategy to produce CoOx nanoparticles and surface N-co-doped carbon aerogels (Co-N-CAs) is reported by multicomponent surface self-assembly of commercially melamine sponge (CMS). In the methodology, the CMS simultaneously function as green N precursor for surface N doping and 3D support. The resulting Co-N-CAs exhibit 3D hierarchical, interconnected macro- and bimodal meso-porosity (6.3 nm and <4 nm), high surface area (1383 m(2) g(-1) ), and highly dispersed, semi-exposured CoOx nanoparticles (diameter of 12.5 nm). The surface doping of N, semi-exposured configuration of CoOx nanoparticles and the penetrated complementary pores (<4 nm) in the carbon walls provide highly accessibility between electroactive components and electrolytes to improve reactivity. With their tailored architecture, the Co-N-CAs show superior electrocatalytic oxygen reduction (ORR) activities comparable to the commercially Pt/C catalysts, high specific capacitance (433 F g(-1) ), excellent lithium storage (938 mAh g(-1) ), and outstanding durability, making them very promising for advanced energy conversion and storage. In addition, the presented strategy can be extended to fabricate other metal oxide- and N- co-doped carbon aerogels for diverse energy-related applications. PMID:25044991

You, Bo; Yin, Peiqun; An, Linna

2014-11-01

286

Complete book of insulating  

SciTech Connect

Insulating makes significant energy conservation possible at relatively modest cost for most householders. Chapters presented are: Making Your Home into an Island; Understanding Heat Flow in Buildings; Weatherstripping and Caulking; Properties of Insulating Materials; Retrofitting Insulation; Installing Insulation in New Buildings; Coping with Other Energy Losers; and Laws, Government Programs, and Codes Affecting Insulation.

Albright, R.; Gay, L.; Stiles, J.; Worman, E.C.; Worman, N.P.; Zak, D.

1980-01-01

287

Photoluminescence properties of silica aerogel/porous silicon nanocomposites  

NASA Astrophysics Data System (ADS)

The luminescent properties of nanocomposite pellets based on silica aerogel and porous Si powder are studied depending on the ratio of chemical compounds. The photoluminescence of nanocomposites is characterized by a red-orange band related to silicon nanoparticles and a blue-green band related to silica aerogel with close values of decay time and activation energy. Remarkable tuning of nanocomposites' photoluminescence spectra in the RGB region is established allowing their use as promising phosphor materials for light-emitting diodes. The outgoing spectra of pellet photoluminescence are guided by the chemical composition ratio, porous Si and silica aerogel technology, and the storage time in ambient atmosphere. It was shown that using the silica aerogel as a dielectric matrix considerably increases the stability of photoluminescence yield of silicon nanoparticles.

Karlash, A. Yu; Zakharko, Yu E.; Skryshevsky, V. A.; Tsiganova, A. I.; Kuznetsov, G. V.

2010-08-01

288

Low dielectric polyimide aerogels as substrates for lightweight patch antennas.  

PubMed

The dielectric properties and loss tangents of low-density polyimide aerogels have been characterized at various frequencies. Relative dielectric constants as low as 1.16 were measured for polyimide aerogels made from 2,2'-dimethylbenzidine (DMBZ) and biphenyl 3,3',4,4'-tetracarbozylic dianhydride (BPDA) cross-linked with 1,3,5-triaminophenoxybenzene (TAB). This formulation was used as the substrate to fabricate and test prototype microstrip patch antennas and benchmark against state of practice commercial antenna substrates. The polyimide aerogel antennas exhibited broader bandwidth, higher gain, and lower mass than the antennas made using commercial substrates. These are very encouraging results, which support the potential advantages of the polyimide aerogel-based antennas for aerospace applications. PMID:23134844

Meador, Mary Ann B; Wright, Sarah; Sandberg, Anna; Nguyen, Baochau N; Van Keuls, Frederick W; Mueller, Carl H; Rodríguez-Solís, Rafael; Miranda, Félix A

2012-11-01

289

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements  

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

290

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

SciTech Connect

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.

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

1994-06-01

291

Integration of carbon aerogels in PEM fuel cells  

Microsoft Academic Search

We prepared resorcinol–formaldehyde (RF) aerogel films with a high molar ratio of resorcinol\\/catalyst (R\\/C) of about 1500 and a low mass ratio of 30%. At the onset of the gelation process, organic fibers or carbon fiber fleece were added to the sol in order to increase the mechanical stability. Upon pyrolysis the RF-aerogel as well as the organic fibers were

M. Glora; M Wiener; R Petri?evi?; H Pröbstle; J Fricke

2001-01-01

292

Oxygen reduction on an iron–carbonized aerogel nanocomposite electrocatalyst  

Microsoft Academic Search

Iron–carbonized aerogel nanocomposite was prepared from highly porous polyacrylonitrile microcellular foams containing a salt of iron, followed by carbonization. The electrochemical reduction of oxygen at this material was studied by using the rotating disk electrode method. In common with Pt\\/C, iron–carbonized aerogel nanocomposite presented excellent electrocatalytic activity for the oxygen reduction under experimental conditions close to those of a fuel

Siyu Ye; Ashok K. Vijh

2005-01-01

293

Surface nature of nanoparticle gold\\/iron oxide aerogel catalysts  

Microsoft Academic Search

The aerogel catalysts investigated are constituted by two chemically different nanoparticle systems consisting of the gold phase and the iron oxide support. High-resolution transmission electronic microscopy (HRTEM) showed an increased surface roughness for aerogel particles with higher gold loading. X-ray photoelectron spectroscopy (XPS) revealed increases in the surface coverage of hydroxyl groups and the Fe2+\\/Fe3+ ratio due to the addition

Chien-Tsung Wang; Shih-Hung Ro

2006-01-01

294

Subcritically dried RF-aerogels catalysed by hydrochloric acid  

Microsoft Academic Search

Hydrochloric acid (HCl) used as catalyst for the preparation of RF-aerogels leads to organic aerogels in very short gelation\\u000a times. The gelation time can be varied from a few seconds to minutes. The wet gels can be dried under ambient conditions.\\u000a By variation of the sol composition or catalyst concentration the microstructure of the dry gels can be modified. The

Michael Reuß; Lorenz Ratke

2008-01-01

295

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

NASA Technical Reports Server (NTRS)

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.

Rhine, Wendell; Polli, Andrew; Deshpande, Kiranmayi

2009-01-01

296

Preparation and application of nanoglued binary titania-silica aerogel.  

PubMed

Nanoglued binary titania (TiO2)-silica (SiO2) aerogel, as a novel type of photocatalyst, has been synthesized on glass substrates. Using an about-to-gel SiO2 sol as nanoglue, anatase TiO2 aerogel was immobilized into a three-dimensional mesoporous network of the SiO2. Factorial designs were employed to optimize both TiO2 aerogel and binary TiO2-SiO2 aerogel synthesis. Characterization of the as-prepared TiO2 and binary samples by surface area, porosity, and surface chemical composition showed that the photocatalysts were high-surface-area nanoporous materials, with a Ti4+ valency. The binary aerogel exhibited high photocatalytic activity for the degradation of methylene blue (MB) under simulated solar light; the reaction followed the pseudo first-order Langmuir-Hinshelwood (L-H) kinetic model. Fluorescence spectroscopy revealed that the hydroxyl (*OH) radical was formed during the illumination of the binary TiO2-SiO2 aerogel in a solution of probe molecules, which corroborates the probable mechanism of hydroxyl radical oxidation of contaminants in photocatalytic reactions. PMID:18495338

Luo, Liang; Cooper, Adrienne T; Fan, Maohong

2009-01-15

297

Silica aerogel: An intrinsically low dielectric constant material  

SciTech Connect

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.

Hrubesh, L.W.

1995-04-01

298

A facile route for 3D aerogels from nanostructured 1D and 2D materials  

E-print Network

Aerogels have numerous applications due to their high surface area and low densities. However, creating aerogels from a large variety of materials has remained an outstanding challenge. Here, we report a new methodology ...

Jung, Sung Mi

299

Polybenzoxazine aerogels: synthesis, characterization, conversion to porous carbons, and energetic composites .  

E-print Network

??"Aerogels are nanoporous, low-density bulk objects, consisting of three-dimensional assemblies of nanoparticle. Structured similarly, polymeric aerogels are emerging as a mechanically strong alternative to traditional… (more)

Mahadik-Khanolkar, Shruti, 1987-

2013-01-01

300

Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold  

DOEpatents

A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

Farmer, Joseph C; Stadermann, Michael

2013-11-12

301

Catalytic combustion of toluene on platinum-containing monolithic carbon aerogels  

Microsoft Academic Search

Monolithic organic aerogels were prepared by the sol–gel procedure from the polymerisation reaction of resorcinol and formaldehyde in water. The organic aerogels were heat treated in inert atmosphere at either 500 or 1000°C to obtain the carbon aerogels. The catalysts were prepared by impregnation with an aqueous solution of [Pt(NH3)4]Cl2 or by dissolving this salt in the initial aerogel mixture.

F. J. Maldonado-Hódar; C. Moreno-Castilla; A. F. Pérez-Cadenas

2004-01-01

302

STS-40 Columbia, OV-102, payload bay aft firewall and thermal insulation  

NASA Technical Reports Server (NTRS)

STS-40 Columbia, Orbiter Vehicle (OV) 102, payload bay (PLB) aft firewall is documented to show a loose piece of thermal insulation. The crew discovered the loose blanket soon after opening the PLB doors on 06-05-91. The vertical tail and the left orbital maneuvering system (OMS) pod are visible above the bulkhead.

1991-01-01

303

The economics of fuel depletion in fast breeder reactor blankets  

E-print Network

A fast breeder reactor fuel depletion-economics model was developed and applied to a number of 1000 MWe UMBR case studies, involving radial blanket-radial reflector design, radial blanket fuel management, and sensitivity ...

Brewer, Shelby Templeton

1972-01-01

304

Evaluation of the parfait blanket concept for fast breeder reactors  

E-print Network

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 ...

Ducat, Glenn Alexander

1974-01-01

305

U. S. ITER shield and blanket design activities  

SciTech Connect

This paper summarizes nuclear-related work in support of the U.S. effort for the Internatinoal Thermonuclear Experimental Reactor (ITER) Study. Primary tasks carried out during the past year include design improvements of the inboard shield developed for the TIBER concept, scoping studies of a variety of tritium breeding blanket options, development of necessary design guidelines and evaluation criteria for the blanket options, further safety considerations related to nuclear components, and issues regarding structural materials for an ITER device. The blanket concepts considered are the aqueous/Li salt solution, a water-cooled, solid-breeder blanket, a helium-cooled, solid-breeder blanket, a helium-cooled, solid-breeder blanket, a blanket cooled by helium containing lithium-bearing particulates, and a blanket concept based on breeding tritium from He/sup 3/.

Baker, C.C.

1989-03-01

306

Studies on preparation and performances of carbon aerogel electrodes for the application of supercapacitor  

Microsoft Academic Search

Carbon aerogel was prepared by the polycondensation of resorcinol (R) with formaldehyde (F), and sodium carbonate was added as a catalyst (C). Physical properties of carbon aerogel were characterized by infrared spectrometer (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that carbon aerogel is an amorphous material with a pearly network structure, and it consists of

Jun Li; Xianyou Wang; Qinghua Huang; Sergio Gamboa; P. J. Sebastian

2006-01-01

307

Zeolite with tunable intracrystal mesoporosity synthesized with carbon aerogel as a secondary template  

Microsoft Academic Search

In this paper, carbon aerogel was investigated as a potential template for generating size controllable intracrystal mesopore system in zeolite. For this purpose zeolite samples were synthesized with carbon aerogels having different structural parameters as secondary template, and characterized with XRD, FT-IR, SEM, TEM as well as low-temperature nitrogen adsorption. Results indicated that the carbon aerogel synthesized by simple ambient

Yunming Fang; Haoquan Hu; Guohua Chen

2008-01-01

308

Preparation of controlled porosity carbon aerogels for energy storage in rechargeable lithium oxygen batteries  

Microsoft Academic Search

Porous carbon aerogels are prepared by polycondensation of resorcinol and formaldehyde catalyzed by sodium carbonate followed by carbonization of the resultant aerogels in an inert atmosphere. Pore structure of carbon aerogels is adjusted by changing the molar ratio of resorcinol to catalyst during gel preparation and also pyrolysis under Ar and activation under CO2 atmosphere at different temperatures. The prepared

Mojtaba Mirzaeian; Peter J. Hall

2009-01-01

309

Determination of the permeability of carbon aerogels by gas flow measurements  

Microsoft Academic Search

Carbon aerogels are synthesized via the polycondensation of resorcinol and formaldehyde, followed by supercritical drying and pyrolysis at 1050°C in nitrogen. Because of their interconnected porosity, ultrafine cell structure and high surface area, carbon aerogels have many potential applications, such as in supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications

F. M. Kong; S. S. Hulsey; C. T. Alviso; R. W. Pekala

1992-01-01

310

Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics  

E-print Network

Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics Moon-Ho Jo aerogel film was characterized from its structural and chemical viewpoints. High porosity of material infrared spectroscopy (FT-IR) for their chemical states. The improved electrical properties of SiO2 aerogel

Jo, Moon-Ho

311

Analysis of the elastic behaviour of silica aerogels taken as a percolating system  

E-print Network

289 Analysis of the elastic behaviour of silica aerogels taken as a percolating system T. Woignier of silica aerogels are performed using the three points flexural technique. The elastic behaviour is studied measurement - for silica aerogels. These highly porous materials are obtained from a sol-gel process. Solvent

Paris-Sud XI, Université de

312

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue  

E-print Network

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue Kyu Hun Kim-based foams10­14 and aero- gels15,16 . However, all nanotube-based foams and aerogels devel- oped so far10,11,13,14 when they are subjected to cyclic strain. Here, we show that an inelastic aerogel made

McGaughey, Alan

313

SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL. F. J. Stadermann  

E-print Network

SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL. F. J. Stadermann 1: Aerogel is the medium of choice for the intact capture of small particles in space, because it is capable materials [1, 2]. After space-exposed aerogel is returned to the laboratory, the first step of analysis

314

DOI: 10.1002/adma.200702781 Aerogel Templated ZnO Dye-Sensitized Solar Cells**  

E-print Network

DOI: 10.1002/adma.200702781 Aerogel Templated ZnO Dye-Sensitized Solar Cells** By Thomas W. Hamann silica aerogel films, featuring a large range of controllable thickness and porosity, are prepared as substructure templates. The aerogel templates are coated with ZnO via atomic layer deposition (ALD) to yield

315

LPSC XXXI Houston, March 2000 SIMS ISOTOPIC ANALYSIS OF INTERPLANETARY DUST FROM SPACE-EXPOSED AEROGEL.  

E-print Network

-EXPOSED AEROGEL. F. J. Stadermann 1,2 and C. Floss 1,3 , 1 Laboratory for Space Sciences, 2 Physics Department, 3@howdy.wustl.edu). Introduction: Aerogel is the medium of choice for the intact capture of small particles in space, because of their component materials [1, 2]. After space-exposed aerogel is returned to the laboratory, the first step

316

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model  

E-print Network

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model Geoffroy J isotherms of 4He in a silica aerogel be- come discontinuous below a critical temperature. We show by the aerogel structure, but to the disorder-driven critical point predicted for the athermal out

Boyer, Edmond

317

Synthesis of Highly Porous Catalytic Layers for Polymer Electrolyte Fuel Cell Based on Carbon Aerogels  

E-print Network

Aerogels J. Mariea , S. Berthon-Fabrya , P. Acharda , M. Chatenetb , E. Chainetb , R. Pirardc , N. Cornetd and characterized carbon aerogels which exhibit high surface area, high porous volume and adjustable pore carbon aerogels with 2 different Nafion loadings. Finally, we characterized the structure

Paris-Sud XI, Université de

318

Three dimensional reconstruction of aerogels from TEM images Florence Despetis1,2  

E-print Network

Three dimensional reconstruction of aerogels from TEM images Florence Despetis1,2 ,Nadjette to compute their physical properties. We focus here on base catalyzed and colloidal silica aerogels, which are fractal materials and we use an original method for the reconstruction of these aerogels from TEM images

Paris-Sud XI, Université de

319

Fabrication of activated carbon fibers/carbon aerogels composites by gelation and supercritical drying  

E-print Network

Fabrication of activated carbon fibers/carbon aerogels composites by gelation and supercritical August 2003) Activated carbon fiber/carbon aerogel (ACF/CA) composites were fabricated by gelling. The ACFs can reinforce the related carbon aerogels when they originally have low mass density and are weak

Liu, Jie

320

Excitations of superfluid 4 He in porous media: Aerogel and Vycor  

E-print Network

Excitations of superfluid 4 He in porous media: Aerogel and Vycor O. Plantevin and B. Fa structure factor S(Q, ) and the elementary excitations of liquid 4 He immersed in aerogel and Vycor. In both and superfluid density, S(T), of liquid 4 He in aerogel and Vycor have been made over the past 30 years.1

Glyde, Henry R.

321

Topic T4 Claudia Hildenbrand #274 EDLC electrodes from cellulose-based carbon aerogels: influence of  

E-print Network

Topic T4 Claudia Hildenbrand #274 EDLC electrodes from cellulose-based carbon aerogels: influence performance if used as EDLC electrode material. Carbon aerogels were synthesized by crosslinking cellulose atmosphere (1000°C, nitrogen atmosphere). Subsequently, the surface chemistry of the carbon aerogels

Paris-Sud XI, Université de

322

TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length  

E-print Network

TESLA-FEL 2004-01 Silica Aerogel Radiators for Bunch Length Measurements J. B¨ahr a , V. Djordjadze aerogel are used to measure the electron bunch length at the photo injector test facility at DESY Zeuthen by the usage of aerogel is calculated analytically and Monte Carlo simulations are performed. It is shown

323

Fusion Power Plants Using Minimum Activity Blankets and MHD Conversion.  

National Technical Information Service (NTIS)

The paper describes a concept for fusion power plants which uses a minimum activity blanket, and MHD for the conversion, to electricity, of the heat deposited in the blanket by neutrons and gamma rays. Two types of blanket design are considered. In the fi...

R. J. Rosa, J. R. Powell

1975-01-01

324

Experimental Studies of Active Temperature Control in Solid Breeder Blankets  

E-print Network

blanket design.[2,3] The packed bed consists of a dispersion of gas and stagnant solid particles. Control1 Experimental Studies of Active Temperature Control in Solid Breeder Blankets M. S. Tillack, A. R barrier regions for solid breeder blankets. In particular, particle beds have been studied because

Tillack, Mark

325

Use of gamma spectroscopy for neutronic analysis of LMFBR Blankets  

E-print Network

It was the purpose of the present investigation to extend and apply Ge(Li) gamma-ray spectroscopy to the study of fast reactor blankets. The focal point for this research was the Blanket Test Facility at the MITR and Blanket ...

Kang, Ch?ang-sun

326

Properties of cryogenic insulants  

Microsoft Academic Search

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

J. Gerhold

1998-01-01

327

Calcium silicate insulation structure  

DOEpatents

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.

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

1995-01-01

328

Reinforcement of silica aerogels using silane-end-capped polyurethanes.  

PubMed

Proper selection of silane precursors and polymer reinforcements yields more durable and stronger silica aerogels. This paper focuses on the use of silane-end-capped urethane prepolymer and chain-extended polyurethane for reinforcement of silica aerogels. The silane end groups were expected to participate in silica network formation and uniquely determine the amounts of urethanes incorporated into the aerogel network as reinforcement. The aerogels were prepared by one-step sol-gel process from mixed silane precursors tetraethoxysilane, aminopropyltriethoxysilane (APTES), and APTES-end-capped polyurethanes. The morphology and mechanical and surface properties of the resultant aerogels were investigated in addition to elucidation of chemical structures by solid-state (13)C and (29)Si nuclear magnetic resonance. Modification by 10 wt % APTES-end-capped chain-extended polyurethane yielded a 5-fold increase in compressive modulus and 60% increase in density. APTES-end-capped chain-extended polyurethane was found to be more effective in enhancement of mechanical properties and reduction of polarity. PMID:23611433

Duan, Yannan; Jana, Sadhan C; Lama, Bimala; Espe, Matthew P

2013-05-21

329

INTOR first wall/blanket/shield activity  

SciTech Connect

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.

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

330

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

331

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

NASA Technical Reports Server (NTRS)

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.

Schonberg, William P.

1993-01-01

332

Composite flexible insulation for thermal protection of space vehicles  

NASA Astrophysics Data System (ADS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the Aeroassist Space Transfer Vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this system are also described. Analytical modeling describing the thermal performance of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1992-09-01

333

Composite flexible insulation for thermal protection of space vehicles  

NASA Technical Reports Server (NTRS)

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the Aeroassist Space Transfer Vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this system are also described. Analytical modeling describing the thermal performance of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.; Tran, Huy K.; Chiu, S. Amanda

1992-01-01

334

Some comments on superfluid 3He placed in globally deformed aerogel  

NASA Astrophysics Data System (ADS)

New experimental results focused on the behavior of the superfluid A-like phase placed in globally deformed aerogel environment are considered. We compare experimental data collected by using optically attested axially stretched silica aerogel, on the one hand, and "nematically ordered" aerogel consisting of nearly parallel Al2O3 · H2O polymer strands, on the other. In the case of axially stretched silica aerogel the point of view was adopted according to which the orbital anisotropy axis l? is long-ranged. The experiments were carried out by pulsed NMR techniques in keeping the direction of an externally applied magnetic field normal to aerogel stretching axis. We have generalized the dipole-locked configuration for arbitrary angle of inclination of the magnetic field with respect to aerogel stretching axis. The experimental data collected in using "nematically ordered" aerogel cannot be reconciled with above-mentioned results.

Baramidze, G. A.; Kharadze, G. A.

2013-08-01

335

Enhanced self-diffusion of adsorbed methanol in silica aerogel  

NASA Astrophysics Data System (ADS)

Molecular transport of a two-component system of liquid and vapor in a porous medium can be anomalously increased owing to fast exchange between the two phases [Phys. Rev. Lett. 63, 43 (1989), 10.1103/PhysRevLett.63.43]. We have investigated this phenomenon measuring the self-diffusion coefficient of methanol adsorbed in a 98% porosity aerogel using nuclear magnetic resonance field gradient techniques. We found enhancement of several orders of magnitude from which we determined the ballistic mean-free path in the vapor phase. We have grown globally uniform anisotropic aerogels and applied the diffusion measurements to characterize the anisotropy. Our results are important for understanding the novel properties of superfluid 3He confined within an aerogel framework and for application to other physical systems.

Lee, Jeongseop A.; Mounce, A. M.; Oh, Sangwon; Zimmerman, A. M.; Halperin, W. P.

2014-11-01

336

Vibration and Thermal Cycling Effects on Bulk-fill Insulation Materials for Cryogenic Tanks  

NASA Astrophysics Data System (ADS)

Large-scale (1,000,000 liters or more) cryogenic storage tanks are typically perlite-insulated double-walled vessels. Associated problems with perlite, such as mechanical compaction and settling, could be greatly reduced by using newer bulk-fill materials such as glass bubbles or aerogel beads. Using the newer materials should translate to lower life cycle costs and improved system reliability. NASA Kennedy Space Center is leveraging its experience in the areas of materials development, insulation testing, and cryogenic systems design to develop an insulation retrofit option that will meet both industry and NASA requirements. A custom 10-liter dewar test apparatus, developed by the KSC Cryogenics Test Laboratory, was used to determine the vibration and thermal cycling effects on different bulk-fill insulation materials for cryogenic tanks. The testing included liquid-nitrogen boiloff testing and thermal cycling (with vibration) of a number of test dewars. Test results show that glass bubbles have better thermal performance and less mechanical compaction compared to perlite powder. The higher cost of the bulk material should be offset by reduced commodity loss from boiloff and improvements in material handling, evacuation, and vacuum retention. The long-term problem with settling and compaction of perlite should also be eliminated. Aerogel beads are superior for the no-vacuum condition and can now be considered in some applications. Further studies on large-scale systems are presently being pursued.

Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.; Sojourner, S. J.; Morris, D. L.

2006-04-01

337

Carbon nanotube networks in epoxy composites and aerogels  

NASA Astrophysics Data System (ADS)

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.

Bryning, Mateusz B.

338

The aerogel grid in Stardust's Sample Return Capsule is deployed.  

NASA Technical Reports Server (NTRS)

In the Payload Hazardous Servicing Facility, workers inspect the aerogel grid from the Stardust Sample Return Capsule (SRC) to the right of the worker. Stardust will use a unique medium called aerogel to capture comet particles flying off the nucleus of comet Wild 2 in January 2004, plus collect interstellar dust for later analysis. The collected samples will return to Earth in the SRC to be jettisoned as it swings by Earth in January 2006. Stardust is scheduled to be launched aboard a Boeing Delta 7426 rocket from Complex 17, Cape Canaveral Air Station, on Feb. 6, 1999.

1998-01-01

339

Highly porous ceramic oxide aerogels having improved flexibility  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

340

Neutronics Assessment of Molten Salt Breeding Blanket Design Options  

SciTech Connect

Neutronics assessment has been performed for molten salt breeding blanket design options that can be utilized in fusion power plants. The concepts evaluated are a self-cooled Flinabe blanket with Be multiplier and dual-coolant blankets with He-cooled FW and structure. Three different molten salts were considered including the high melting point Flibe, a low melting point Flibe, and Flinabe. The same TBR can be achieved with a thinner self-cooled blanket compared to the dual-coolant blanket. A thicker Be zone is required in designs with Flinabe. The overall TBR will be {approx}1.07 based on 3-D calculations without breeding in the divertor region. Using Be yields higher blanket energy multiplication than obtainable with Pb. A modest amount of tritium is produced in the Be ({approx}3 kg) over the blanket lifetime of {approx}3 FPY. Using He gas in the dual-coolant blanket results in about a factor of 2 lower blanket shielding effectiveness. We show that it is possible to ensure that the shield is a lifetime component, the vacuum vessel is reweldable, and the magnets are adequately shielded. We conclude that molten salt blankets can be designed for fusion power plants with neutronics requirements such as adequate tritium breeding and shielding being satisfied.

Sawan, M.E. [University of Wisconsin-Madison (United States); Malang, S. [Fusion Nuclear Technology Consulting (United States); Wong, C.P.C. [General Atomics (United States); Youssef, M.Z. [University of California-Los Angeles (United States)

2005-04-15

341

Measuring insulation thickness  

NASA Technical Reports Server (NTRS)

Calibrated eddy-current meter measures thickness of thermal insulation on metal substrates with specially designed adapters; for example, thickness of fiberglass parts for boats or automobiles. Technique is particlarly useful for sprayed-on insulation.

Munn, D. M.

1979-01-01

342

Natural circulation in fusion reactor blankets  

Microsoft Academic Search

The relative importance of natural circulation and heat conduction as heat transfer mechanisms in lithium, sodium and flibe is investigated for a range of magnetic field strengths of interest in fusion reactor blankets. The calculations are based on an order-of-magnitude simplification of the fluid equations, and a modified version of the fission reactor thermal-hydraulic code THERMIT. The results show that

P. J. Gierszewski; B. Mikic; N. E. Todreas

1980-01-01

343

Nuclear Analysis of an ITER Blanket Module  

NASA Astrophysics Data System (ADS)

ITER blanket system is the reactor's plasma-facing component, it is mainly devoted to provide the thermal and nuclear shielding of the Vacuum Vessel and external ITER components, being intended also to act as plasma limiter. It consists of 440 individual modules which are located in the inboard, upper and outboard regions of the reactor. In this paper attention has been focused on to a single outboard blanket module located in the equatorial zone, whose nuclear response under irradiation has been investigated following a numerical approach based on the Monte Carlo method and adopting the MCNP5 code. The main features of this blanket module nuclear behaviour have been determined, paying particular attention to energy and spatial distribution of the neutron flux and deposited nuclear power together with the spatial distribution of its volumetric density. Moreover, the neutronic damage of the structural material has also been investigated through the evaluation of displacement per atom and helium and hydrogen production rates. Finally, an activation analysis has been performed with FISPACT inventory code using, as input, the evaluated neutron spectrum to assess the module specific activity and contact dose rate after irradiation under a specific operating scenario.

Chiovaro, P.; Di Maio, P. A.; Parrinello, V.

2013-08-01

344

Thermal insulating mat  

SciTech Connect

In order to fabricate and emplace a thermal insulating mat at favorable cost and in order to provide the mat with good thermal insulation properties at a favorable cost, the thermal insulating mat comprises films having sealed chambers which are filled with a filler gas, the thermal conduction coefficient of which is smaller than that of air.

May, M. G.

1985-08-06

345

Topological Insulators & Superconductors  

E-print Network

Topological Insulators & Superconductors New Frontiers in Low-Dimensional Systems Program 3-5 November 2010 Jadwin Hall, Fourth Floor, Room 407 Topological Insulators and Superconductors have quickly insulators but have holographic edge or surface states which are robust to disorder and impurities

346

SOUND INSULATION ISSUES  

Microsoft Academic Search

This paper gives an overview of three topics related to sound insulation in buildings. The first project included laboratory and field measurements of sound insulation against aircraft noise. As well as various technical papers, the project produced software to help in the design of adequate sound insulation. In a second project, re-analysis of survey results allowed the development of a

John S. Bradley

347

Synthesis, characterization, and modeling of hydrogen storage in carbon aerogels  

SciTech Connect

Carbon aerogels are a special class of open-cell foams with an ultrafine cell/pore size (<50 nm), high surface area (600-800 m{sup 2}/g), and a solid matrix composed of interconnected colloidal-like particles or fibers with characteristic diameters of 10 nm. These materials are usually synthesized from the sol-gel polymerization of resorcinol-formaldehyde or phenolic-furfural, followed by supercritical extraction of the solvent and pyrolysis in an inert atmosphere. The resultant aerogel has a nanocrystalline structure with micropores (<2 nm diameter) located within the solid matrix. Carbon aerogel monoliths can be prepared at densities ranging from 0.05-1.0 g/cm{sup 3}, leading to volumetric surface areas (> 500 m{sup 2}/cm{sup 3}) that are much larger than commercially available materials. This research program is directed at optimization of the aerogel structure for maximum hydrogen adsorption over a wide range of temperatures and pressures. Computer modeling of hydrogen adsorption at carbon surfaces was also examined.

Pekala, R.W.; Coronado, P.R.; Calef, D.F.

1995-04-01

348

Optical properties of single-walled carbon nanotube aerogels  

NASA Astrophysics Data System (ADS)

A network of connected single-walled carbon nanotubes (SWNT) is created by a novel DNA-protein complex directed assembly. Due to a point-like nature of connectors, the SWNT aerogel represents a network of self-suspended nanotubes with a record ultra-low density of less 0.75 mg/cm^3. The assembly method and low density enables a direct comparison of optical properties of nanotubes in solvent and air to surfactant solubilized nanotubes. Optical properties of SWNT gels are investigated using optical absorption, photoluminescence and Raman spectroscopy. Gelled nanotubes in water and in the low population regime behave similar to solubilized nanotubes. In contrast, photoluminescence of SWNT aerogels exhibit nonlinear effects and a phonon-induced broadening. In addition, aerogels show a previously unobserved photoluminescence peak at 1.3 eV that corresponds to a phonon-assisted recombination of photoexcited charges. Raman spectra of carbon nanotube aerogels display narrow peaks due to the phonon decoupling of suspended SWNTs in air and a redistribution of G phonon population due to nonlinear effects.

Ostojic, Gordana

2012-02-01

349

Controlled nanoporosity of organic aerogels by dispersing clay platelets.  

PubMed

A new class of organic-inorganic hybrid aerogels having small pores and narrow pore size distribution are synthesized from well-dispersed clay platelets in water as base catalyst. Clay-catalyzed organic gels have strong advantage in controlling nanopore structure as well as reducing drying shrinkage by reinforcing the organic network with inorganic platelets. PMID:22080301

Kim, Kwang Hee; Park, Sangho; Hwang, Sungwoo; Cho, Myung-D

2012-01-11

350

Surface plasmon resonance evaluation of colloidal silver aerogel filters  

Microsoft Academic Search

Aerogels containing silver nanoparticles were fabricated 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 heterogeneous or porous media. Specifically, we extend the predominant effective medium theories for the determination of the average fractional composition of each component in

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

1998-01-01

351

Reinforcement of bacterial cellulose aerogels with biocompatible polymers  

PubMed Central

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

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

2014-01-01

352

Transparent conducting aerogels of antimony-doped tin oxide.  

PubMed

Bulk antimony-doped tin oxide aerogels are prepared by epoxide-initiated sol-gel processing. Tin and antimony precursors are dissolved in ethanol and water, respectively, and propylene oxide is added to cause rapid gelation of the sol, which is then dried supercritically. The Sb:Sn precursor mole ratio is varied from 0 to 30% to optimize the material conductivity and absorbance. The materials are characterized by electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), nitrogen physisorption analysis, a four-point probe resistivity measurement, and UV-vis diffuse reflectance spectroscopy. The samples possess morphology typical of aerogels without significant change with the amount of doping. Calcination at 450 °C produces a cassiterite crystal structure in all aerogel samples. Introduction of Sb at 15% in the precursor (7.6% Sb by XPS) yields a resistivity more than 3 orders of magnitude lower than an undoped SnO2 aerogel. Calcination at 800 °C reduces the resistivity by an additional 2 orders of magnitude to 30 ?·cm, but results in a significant decrease in surface area and pore volume. PMID:25296169

Correa Baena, Juan Pablo; Agrios, Alexander G

2014-11-12

353

Nuclear Magnetic Resonance Studies of Resorcinol-Formaldehyde Aerogels  

SciTech Connect

In this article we report a detailed study of resorcinol-formaldehyde (RF) aerogels prepared under different processing conditions, [resorcinol]/[catalyst] (R/C) ratios in the starting sol-gel solutions, using continuous flow hyperpolarized 129Xe NMR in combination with solid-state 13C and two-dimensional wide-line separation (2D-WISE) NMR techniques. The degree of polymerization and the mobility of the cross-linking functional groups in RF aerogels are examined and correlated with the R/C ratios. The origin of different adsorption regions is evaluated using both co-adsorption of chloroform and 2D EXSY 129Xe NMR. A hierarchical set of Xe exchange processes in RF aerogels is found using 2D EXSY 129Xe NMR. The exchange of Xe gas follows the sequence (from fastest to slowest): mesopores with free gas, gas in meso- and micro-pores, free gas with micropores, and, finally, among micropore sites. The volume-to-surface-area (Vg/S) ratios for aerogels are measured for the first time without the use of geometric models. The Vg/S parameter, which is related both to the geometry and the interconnectivity of the pore space, has been found to correlate strongly with the R/C ratio and exhibits an unusually large span: an increase in the R/C ratio from 50 to 500 results in about a 5-fold rise in Vg/S.

Moudrakovski, Igor L.; Ratcliffe, C I.; Ripmeester, J A.; Wang, Li Q.; Exarhos, Gregory J.; Baumann, T; Satcher, J H.

2005-06-09

354

Noble Metal Immersion Spectroscopy of Silica Alcogels and Aerogels  

Microsoft Academic Search

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

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

2000-01-01

355

Porous silicon nanocrystals in a silica aerogel matrix  

NASA Astrophysics Data System (ADS)

Silicon nanoparticles of three types (oxide-terminated silicon nanospheres, micron-sized hydrogen-terminated porous silicon grains and micron-size oxide-terminated porous silicon grains) were incorporated into silica aerogels at the gel preparation stage. Samples with a wide range of concentrations were prepared, resulting in aerogels that were translucent (but weakly coloured) through to completely opaque for visible light over sample thicknesses of several millimetres. The photoluminescence of these composite materials and of silica aerogel without silicon inclusions was studied in vacuum and in the presence of molecular oxygen in order to determine whether there is any evidence for non-radiative energy transfer from the silicon triplet exciton state to molecular oxygen adsorbed at the silicon surface. No sensitivity to oxygen was observed from the nanoparticles which had partially H-terminated surfaces before incorporation, and so we conclude that the silicon surface has become substantially oxidised. Finally, the FTIR and Raman scattering spectra of the composites were studied in order to establish the presence of crystalline silicon; by taking the ratio of intensities of the silicon and aerogel Raman bands, we were able to obtain a quantitative measure of the silicon nanoparticle concentration independent of the degree of optical attenuation.

Amonkosolpan, Jamaree; Wolverson, Daniel; Goller, Bernhard; Polisski, Sergej; Kovalev, Dmitry; Rollings, Matthew; Grogan, Michael D. W.; Birks, Timothy A.

2012-07-01

356

Development of transparent silica aerogel over a wide range of densities  

E-print Network

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.

Makoto Tabata; Ichiro Adachi; Yoshikazu Ishii; Hideyuki Kawai; Takayuki Sumiyoshi; Hiroshi Yokogawa

2011-12-21

357

Development of transparent silica aerogel over a wide range of densities  

E-print Network

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.

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

2011-01-01

358

Insulated solar storage tanks  

SciTech Connect

This paper presents the theoretical and experimental investigation of an insulated parallelepiped, outdoor solar, water-filled storage tank of size 1 m {times} 0.5 m {times} 0.3 m, that is made from galvanized iron. The absorption coefficient of the insulating material has been determined. The effects of plastic covers and insulation thickness on the water temperature and the energy gained or lost by water are investigated. Moreover, the effects of insulation thickness on the temperature profiles of the insulating material are discussed. The results show that the absorption coefficient decreases as the insulation thickness increases. Also, it is found that the glass wool insulation of 2.5 cm thickness has the best results compared with the other thicknesses (5 cm, 7.5 cm, and 10 cm) as far as the water temperature and the energy gained by water are concerned.

Eldighidy, S.M. (Sultan Qaboos Univ., Muscat (Oman))

1991-01-01

359

Supercritical drying preparation and fractal structure of blue luminescent silica aerogel  

Microsoft Academic Search

A blue luminescent silica monolithic aerogel was prepared by a sol-gel process followed supercritical drying. The as-prepared silica aerogels are transparent and exhibit blue luminescence excited by a near UV light of 365 nm wavelength. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the monolithic aerogel had micropores and nanopores. Small angle X-ray scattering analysis showed that

S. B. Xiong; Z. M. Ye; Z. G. Liu; W. P. Ding; X. Q. Zheng; Y. P. Zhu; C. Y. Lin

1997-01-01

360

Preparation and characterization of antibacterial silver-dispersed activated carbon aerogels  

Microsoft Academic Search

Silver-dispersed carbon aerogels (CAs) were obtained by direct immersion of organic aerogels prepared by ambient pressure drying technique in AgNO3 aqueous solution and then carbonization. The effect of preparation conditions such as the resorcinol\\/catalyst ratio, the feed AgNO3 concentration, the ratio of aerogel mass\\/solution volume, immersion time and carbonization temperature on the bulk density and silver content as well as

Shuting Zhang; Ruowen Fu; Dingcai Wu; Wei Xu; Qiwei Ye; Zhangliu Chen

2004-01-01

361

Highly dispersed platinum–carbon aerogel catalyst for polymer electrolyte membrane fuel cells  

Microsoft Academic Search

Platinum loaded carbon aerogel catalysts for application in polymer electrolyte membrane fuel cells have been synthesized from the alcoholic sol–gel reaction of phloroglucinol with furfural using propylene oxide as a reducing agent of platinum salt, followed by supercritical drying with carbon dioxide. Subsequent carbonization of the platinum–organic aerogels under a reducing gas flow produced platinum–carbon aerogels. X-ray diffraction and transmission

Hyun-Joong Kim; Won-Il Kim; Tae-Jin Park; Hyung-Sang Park; Dong Jin Suh

2008-01-01

362

Nano-sized metal-doped carbon aerogel for pseudo-capacitive supercapacitor  

Microsoft Academic Search

Carbon aerogel was prepared by polycondensation of resorcinol with formaldehyde using sodium carbonate as a catalyst in ambient conditions. Nano-sized Ni-doped carbon aerogel was then prepared by a precipitation method in an ethanol solvent. In order to elucidate the effect of Ni content on electrochemical properties, nano-sized Ni-doped carbon aerogels with different Ni content (21, 35, 60, and 82 wt%) were

Yoon Jae Lee; Sunyoung Park; Jeong Gil Seo; Jung Rag Yoon; Jongheop Yi; In Kyu Song

2011-01-01

363

Development of new silica aerogel for the RICH radiator of the Super Belle detector  

Microsoft Academic Search

Currently, we are working on the program of the Belle detector upgrade, and the Cherenkov ring imaging counter with silica aerogel radiator (aerogel-RICH) is the most promising candidate for the particle identification device (PID) at the endcap section of the BELLE detector, where a threshold-type aerogel Cherenkov counter is occupied at present, in order to further expand pi-K separation capabilities

Adachi; S. Fratina; T. Fukushima; A. Gorisek; T. Iijima; H. Kawai; H. Kishimoto; M. Konishi; S. Korpar; Y. Kozakai; P. Krizan; T. Matsumoto; S. Nishida; S. Ogawa; R. Pestotnik; S. Saitoh; T. Seki; T. Sumiyoshi; Y. Uchida; Y. Unno; S. Yamamoto; H. Yokogawa

2004-01-01

364

Characterization and electrochemical performance of graphene-containing carbon aerogel for supercapacitor.  

PubMed

Graphene-containing carbon aerogel was prepared by a polycondensation of resorcinol with formaldehyde using chemically exfoliated graphene oxide in ambient conditions, and its electrochemical performance as an electrode for supercapacitor was examined. The effect of pH in the preparation of RFGO (resorcinol-formaldehyde and graphene oxide) solution on the physical and electrochemical properties of graphene-containing carbon aerogel was investigated. For comparison, graphene-free carbon aerogel was also prepared. Among the samples, graphene-containing carbon aerogel prepared at pH 6.5 showed the highest BET surface area (733 m2/g) and the largest pore volume (1.39 cm3/g) with well-developed porous structure. Electrochemical properties of graphene-containing carbon aerogel and graphene-free carbon aerogel electrodes were measured by cyclic voltammetry at a scan rate of 10 mV/sec and by charge/discharge test at constant current of 1 A/g in 6 M KOH electrolyte. From cyclic voltammetry measurements, it was found that graphene-containing carbon aerogel prepared at pH 6.5 showed higher specific capacitance than graphene-free carbon aerogel (63 F/g vs. 54 F/g). Specific capacitance calculated by charge/discharge test also revealed that graphene-containing carbon aerogel prepared at pH 6.5 showed higher specific capacitance than graphene-free carbon aerogel (85 F/g vs. 79 F/g). Thus, electrochemical performance of graphene-containing carbon aerogel prepared at pH 6.5 could be enhanced by adding graphene into carbon aerogel. PMID:24266169

Lee, Yoon Jae; Park, Hai Woong; Hong, Ung Gi; Song, In Kyu

2013-12-01

365

Removal of bromide and iodide anions from drinking water by silver-activated carbon aerogels  

Microsoft Academic Search

The aim of this study is to analyze the use of Ag-doped activated carbon aerogels for bromide and iodide removal from drinking water and to study how the activation of Ag-doped aerogels affects their behavior. It has been observed that the carbonization treatment and activation process of Ag-doped aerogels increased the surface area value (SN2), whereas the volume of meso-(V2)

M. Sánchez-Polo; J. Rivera-Utrilla; E. Salhi; U. von Gunten

2006-01-01

366

Dye-sensitized titania aerogels as photovoltaic electrodes for electrochemical solar cells  

Microsoft Academic Search

We describe the fabrication and performance of dye-sensitized photoanodes derived from TiO2 aerogel. Nanocrystalline titania aerogel is a bicontinuous, nanostructured pore–solid architecture featuring specific surface areas of 85–150m2\\/g and a continuous mesoporous network, allowing chemisorption of high concentrations of sensitizing dye and rapid mass-transport of electron-transfer mediators. Considerable design and processing flexibility arises with aerogels because the continuous pore–solid networks

Jeremy J. Pietron; Arnold M. Stux; Ratonya S. Compton; Debra R. Rolison

2007-01-01

367

Synthesis of Alumina Aerogels by Ambient Drying Method and Control of Their Structures  

Microsoft Academic Search

A new method to synthesize alumina aerogels was introduced in this article. Alumina aerogels were firstly prepared by sol-gel process, using Al(?) inorganic compound as a precursor, 1,2-epoxy propane as a gelation inducing agent (GIA) and methane amide as drying control chemical additive (DCCA), followed by ambient drying method (ADM). The bulk alumina aerogels were examined by TEM, SEM and

Lihua Gan; Zijie Xu; Ying Feng; Longwu Chen

2005-01-01

368

Evidence for a disorder driven phase transition in the condensation of 4He in aerogels  

E-print Network

We report on thermodynamic and optical measurements of the condensation process of $^4$He in three silica aerogels of different microstructures. For the two base-catalysed aerogels, the temperature dependence of the shape of adsorption isotherms and of the morphology of the condensation process show evidence of a disorder driven transition, in agreement with recent theoretical predictions. This transition is not observed for a neutral-catalysed aerogel, which we interpret as due to a larger disorder in this case.

Fabien Bonnet; Thierry Lambert; Benjamin Cross; Laurent Guyon; Florence Despetis; Laurent Puech; Pierre-Etienne Wolf

2008-02-21

369

75 FR 50991 - Antidumping Duty Order: Certain Woven Electric Blankets From the People's Republic of China  

Federal Register 2010, 2011, 2012, 2013

...A-570-951] Antidumping Duty Order: Certain Woven Electric Blankets From the People's Republic of China...issuing an antidumping duty order on certain woven electric blankets (``woven electric blankets'') from the People's Republic...

2010-08-18

370

Europium-Containing Organic Gels and Organic and Carbon Aerogels. Preparation and Initial Applications in Catalysis  

Microsoft Academic Search

Summary.  We prepared organic gels and organic and carbon aerogels doped with europium through sol–gel processes. Eu-gels were prepared\\u000a by sol–gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde followed by ion-exchange with\\u000a Eu(OTf)3. Eu–organic aerogels were obtained after CO2 supercritical drying of the gels and Eu–carbon aerogels were obtained by pyrolysing the organic aerogels. The Eu-gels containing\\u000a 12%

Sandra Martínez; Laura Martín; Elies Molins; Marcial Moreno-Mañas; Anna Roig; Adelina Vallribera

2006-01-01

371

Thermal properties of granular silica aerogel for high-performance insulation systems  

E-print Network

Based on mounting evidence in support of anthropogenic global climate change, there is an urgency for developments in high-performance building techniques and technologies. New construction projects provide substantial ...

Neugebauer, Adam (Adam Halbert)

2013-01-01

372

Ambient-dried silica aerogel doped with TiO2 powder for thermal insulation  

Microsoft Academic Search

Two step-derived SiO2 sol doped with TiO2 powder dissolved in ethanol was prepared. After aging and washing of wet gel, surface modification with TMCS (trimethylchlorosilane) was followed to prevent additional condensation reaction during drying. Ambient-dried SiO2-TiO2 gel was heat-treated at various temperatures. The effects of the heat-treated temperature on the chemical bonding state of SiO2-TiO2 gel were investigated by means

Young-Geun Kwon; Se-Young Choi; Eul-Son Kang; Seung-Su Baek

2000-01-01

373

Evacuated Panels Utilizing Clay-Polymer Aerogel Composites for Improved Housing Insulation  

E-print Network

($ per ft³) Loose-fill Cellulose 3.5 1.81 Expanded Polystyrene 4.0 3.20 Fiber glass 3.1 1.63 Perlite 2.04 Polyurethane Foam 5.6 6.32 Fiber glass 3.9 6.12 Perlite 2.6 7.32 Miscellaneous SIP 4.7 9 -15 Pure Silica

Rollins, Andrew M.

374

Study of multilayered insulation pipe penetration. Thermal acoustic oscillation  

NASA Technical Reports Server (NTRS)

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.

Lovin, J. K.

1974-01-01

375

Condensation of helium in aerogels as an experimental realization of the out-of-equilibrium Random Field Ising Model  

E-print Network

Condensation of helium in aerogels as an experimental realization of the out-of-equilibrium Random-catalysed silica aerogels of large porosity presents a similar out-of-equilibrium behavior when the temperature

376

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

E-print Network

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 ...

Zuo, Yanjia

2010-01-01

377

High temperature - low mass solar blanket  

NASA Technical Reports Server (NTRS)

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.

Mesch, H. G.

1979-01-01

378

ITER solid breeder blanket materials database  

SciTech Connect

The databases for solid breeder ceramics (Li{sub 2},O, Li{sub 4}SiO{sub 4}, Li{sub 2}ZrO{sub 3} and LiAlO{sub 2}) and beryllium multiplier material are critically reviewed and evaluated. Emphasis is placed on physical, thermal, mechanical, chemical stability/compatibility, tritium, and radiation stability properties which are needed to assess the performance of these materials in a fusion reactor environment. Correlations are selected for design analysis and compared to the database. Areas for future research and development in blanket materials technology are highlighted and prioritized.

Billone, M.C. [Argonne National Lab., IL (United States); Dienst, W. [Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Material- und Festkoerperforschung; Flament, T. [CEA Centre d`Etudes de Fontenay-aux-Roses (France). Commissariat A L`Energie Atomique; Lorenzetto, P. [NET Team, Garching (Germany); Noda, K. [Japan Atomic Energy Research Inst., Takai, Ibaraki, (Japan); Roux, N. [CEA Centre d`Etudes et de Recherches Les Materiaux (France). Commissariat a L`Energie Atomique

1993-11-01

379

Specific welds for test blanket modules  

NASA Astrophysics Data System (ADS)

Fabrication and assembling test blanket modules needs a variety of different welding techniques. Therefore, an evaluation of plate joining for breeder units by tungsten-inert-gas, laser, and electron beam welding was performed by qualification of relevant mechanical properties like hardness, charpy, and creep strength. The focus was laid on the study of post-weld heat treatments at lowest possible temperatures and for maximum recovery of the joints. The most important result is that thin EUROFER plates may be welded by EB or laser techniques without the necessity of post-welding heat treatments that include an austenitization step.

Rieth, Michael; Rey, Jörg

2009-04-01

380

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)

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.

Stochl, Robert J.; Knoll, Richard H.

1991-06-01

381

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)

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.

Stochl, Robert J.; Knoll, Richard H.

1991-01-01

382

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)

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.

Stochl, Robert J.; Knoll, Richard H.

1991-06-01

383

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)

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.

Stochl, Robert J.; Knoll, Richard H.

1991-01-01

384

Vibration considerations for cryogenic tanks using glass bubbles insulation  

NASA Astrophysics Data System (ADS)

The use of glass bubbles as an efficient and practical thermal insulation system hasbeen previously demonstrated in cryogenic storage tanks. One such example is a spherical,vacuum-jacketed liquid hydrogen vessel of 218,000 liter capacity where the boiloff rate hasbeen reduced by approximately 50 percent. Further applications may include non-stationarytanks such as mobile tankers and tanks with extreme duty cycles or exposed to significantvibration environments. Space rocket launch events and mobile tanker life cycles representtwo harsh cases of mechanical vibration exposure. A number of bulk fill insulationmaterials including glass bubbles, perlite powders, and aerogel granules were tested forvibration effects and mechanical behavior using a custom design holding fixture subjectedto random vibration on an Electrodynamic Shaker. The settling effects for mixtures ofinsulation materials were also investigated. The vibration test results and granular particleanalysis are presented with considerations and implications for future cryogenic tankapplications.

Werlink, Rudy John; Fesmire, James; Sass, Jared P.

2012-06-01

385

Flow through macropores of different size classes in blanket peat  

Microsoft Academic Search

Blanket peats are important source areas for runoff in many northern European headwaters. The upper peat layer (20 cm) is dominant in producing flow in blanket peat catchments. However, little information exists on the relative roles of different size classes of macropore in water movement in this upper peat layer. This study uses results from tension infiltrometer experiments to assess

Joseph Holden

2009-01-01

386

27 CFR 40.134 - Amount of blanket bond.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Amount of blanket bond. 40.134 Section 40.134 Alcohol, Tobacco...CIGARETTE PAPERS AND TUBES, AND PROCESSED TOBACCO Bonds and Extensions of Coverage of Bonds § 40.134 Amount of blanket bond. In...

2010-04-01

387

Tritium management in HCLL-PPCS model AB blanket  

Microsoft Academic Search

When dealing with activities related to the design and optimisation of the Helium Cooled Lithium Lead (HCLL) blanket, doubts arose in the past about the technical feasibility of the tritium processing system. The questionable feasibility was due to the heavy performance requirements for different tritium processing subsystems, mainly consequence of the high tritium permeation rate from the breeding blanket into

I. Ricapito; A. Aiello; A. Ciampichetti; G. Benamati; M. Utili; M. Zucchetti

2007-01-01

388

Neutronics analysis for aqueous self-cooled fusion reactor blankets  

Microsoft Academic Search

The tritium breeding performance of several Aqueous Self-Cooled Blanket (ASCB) configurations for fusion reactors has been evaluated. The ASCB concept employs small amounts of lithium compound dissolved in light or heavy water to serve as both coolant and breeding medium. The inherent simplicity of this concept allows the development of blankets with minimal technological risk. The tritium breeding performance of

M. J. Embrechts; G. Varsamis; R. Jaffa; D. Steiner; L. Deutsch; P. Gierszewski

1986-01-01

389

Testing needs and experiments for solid breeder blankets  

Microsoft Academic Search

Most of the critical issues for solid breeder blankets are related to the tritium and thermomechanical behavior of the solid breeder and multiplier. A major contributor to this uncertainty is the lack of definition of a preferred material, microstructure and form. Material selection and development is particularly cost-effective at present since much of the important blanket behavior is driven by

P. Gierszewski; R. Puigh

1986-01-01

390

THORIUM OXIDE BLANKET FABRICATION FOR INDIAN FAST BREEDER TEST REACTOR  

Microsoft Academic Search

For an effective utilisation of Thorium in FBRs, use of fertile blanket of thorium oxide\\/thorium mast be considered. Development of a reliable and economic fabrication technique of this fertile material, thus is an important step in the ultimate goal of utilization of thorium in FBRs. Fabrication and supply of blanket assemblies containing thorium oxide pellets to the requisite quality, for

P. BALAKRISHNA; B. P. VARMA; R. RAJENDRAN

391

NEUTRONICS DESIGN STUDIES OF AN LBE COOLED ATW BLANKET  

Microsoft Academic Search

As part of the Advanced Accelerator Application (AAA) program in the US, preliminary trade studies have been performed at Argonne National Laboratory (ANL) and Los Alamos National Laboratory (LANL) to define and compare candidate Accelerator Transmutation of Waste (ATW) systems. The studies at ANL have focused primarily on the blanket component of the overall system, because the choice of blanket

W. S. YANG; H. S. KHALIL

392

Review of blanket designs for advanced fusion reactors  

Microsoft Academic Search

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

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

393

Simple holographic insulator  

NASA Astrophysics Data System (ADS)

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.

Mefford, Eric; Horowitz, Gary T.

2014-10-01

394

Multilayer Insulation Material Guidelines  

NASA Technical Reports Server (NTRS)

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.

Finckenor, M. M.; Dooling, D.

1999-01-01

395

Loose-fill insulations  

SciTech Connect

Whether you are increasing the insulation levels in your current home or selecting insulation for a new home, choosing the right insulation material can be challenging. Fibrous loose-fill insulations such as cellulose, fiberglass, and rock wool are options you may wish to consider. This publication will introduce you to these materials--what they are, how they are applied, how they compare with each other, and other considerations regarding their use--so that you can decide whether loose fills are right for your home.

NONE

1995-05-01

396

Topological crystalline insulator nanostructures.  

PubMed

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 Bi2Se3 and Bi2Te3, 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, Pb1-xSnxSe, and Pb1-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 Bi2Se3 and Bi2Te3. 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

Shen, Jie; Cha, Judy J

2014-11-01

397

Physical and mechanical characteristics and chemical compatibility of aluminum nitride insulator coatings for fusion reactor applications  

SciTech Connect

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 Blanket Comparison and Selection Study, conducted earlier, described the overall comparative performance of various concepts, including liquid metal, molten salt, water, and helium. Based on the requirements for an electrically insulating coating on the first-wall structural material to minimize the MHD pressure drop during the flow of liquid metal in a magnetic field, AlN was selected as a candidate coating material for the Li self-cooled blanket concept. This report discusses the results from an ongoing study of physical and mechanical characteristics and chemical compatibility of AlN electrical insulator coatings in a liquid Li environment. Details are presented on the AlN coating fabrication methods, and experimental data are reported for microstructures, chemistry of coatings, pretreatment of substrate, heat treatment of coatings, hardness data for coatings, coating/lithium interactions, and electrical resistance before and after exposure to lithium. Thermodynamic calculations are presented to establish regions of stability for AlN coatings in an Li environment as a function of O concentration and temperature, which can aid in-situ development of AlN coatings in Li.

Natesan, K.; Rink, D.L. [Argonne National Lab., IL (United States). Energy Technology Div.

1996-04-01

398

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

SciTech Connect

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.

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

1990-08-01

399

MIT LMFBR blanket research project. Final summary report  

SciTech Connect

This is a final summary report on an experimental and analytical program for the investigation of LMFBR blanket characteristics carried out at MIT in the period 1969 to 1983. During this span of time, work was carried out on a wide range of subtasks, ranging from neutronic and photonic measurements in mockups of blankets using the Blanket Test Facility at the MIT Research Reactor, to analytic/numerical investigations of blanket design and economics. The main function of this report is to serve as a resource document which will permit ready reference to the more detailed topical reports and theses issued over the years on the various aspects of project activities. In addition, one aspect of work completed during the final year of the project, on doubly-heterogeneous blanket configurations, is documented for the record.

Driscoll, M.J.

1983-08-01

400

Electrochemical behavior of carbon aerogels derived from different precursors  

SciTech Connect

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.

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

401

Stability of superfluid 3He-B in compressed aerogel.  

PubMed

In recent work, it was shown that new anisotropic p-wave states of superfluid (3)He can be stabilized within high-porosity silica aerogel under uniform positive strain. In contrast, the equilibrium phase in an unstrained aerogel is the isotropic superfluid B phase. Here we report that this phase stability depends on the sign of the strain. For a negative strain of ? 20% achieved by compression, the B phase can be made more stable than the anisotropic A phase, resulting in a tricritical point for A, B, and normal phases with a critical field of ? 100 mT. From pulsed NMR measurements, we identify these phases and the orientation of the angular momentum. PMID:24702386

Li, J I A; Zimmerman, A M; Pollanen, J; Collett, C A; Gannon, W J; Halperin, W P

2014-03-21

402

Aerogel RICH for forward PID at Belle II  

NASA Astrophysics Data System (ADS)

For the Belle II spectrometer we are preparing a proximity focusing RICH with aerogel as the radiator. It will be positioned in the forward direction of the spectrometer in the small space between the drift chamber and the electromagnetic calorimeter inside a strong magnetic field of 1.5 T. The Hybrid Avalanche Photo Diode used as a photo sensor, is able to detect single photons with a high efficiency, can operate in the magnetic field and is resistant to the expected neutron and gamma fluxes in the detector. By detecting more than 11 photons per incident 4 GeV/c pion, with 15 mrad single photon Cherenkov angle resolution, the designed aerogel RICH should enable an efficient separation of kaons from pions in the wide range of particle momenta from 0.5 GeV/c up to 4 GeV/c.

Pestotnik, R.; Adachi, I.; Hara, K.; Higuchi, M.; Iijima, T.; Iwata, S.; Kakuno, H.; Kawai, H.; Kawasaki, T.; Korpar, S.; Križan, P.; Kumita, T.; Mori, W.; Nishida, S.; Ogawa, S.; Šantelj, L.; Sakashita, Y.; Seljak, A.; Sumiyoshi, T.; Tabata, M.; Takagaki, H.; Yusa, Y.; Verheyden, R.

2013-12-01

403

Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy and ultra-small angle  

E-print Network

Very large-scale structures in sintered silica aerogels as evidenced by atomic force microscopy of silica aerogels has been extensively studied mainly by scattering techniques (neutrons, X-rays, light) and atomic force microscopy (AFM) experiments have been carried out on aerogels at dierent steps of densi

Demouchy, Sylvie

404

Studies of the Chemical and Pore Structures of the Carbon Aerogels Synthesized by Gelation and Supercritical Drying  

E-print Network

Studies of the Chemical and Pore Structures of the Carbon Aerogels Synthesized by Gelation August 2003 ABSTRACT: The carbon aerogels prepared by a new method through gelation and supercritical are discussed. We found that all of these carbon aerogel (CA-IPA) samples have almost the same carbon and oxygen

Liu, Jie

405

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Jiangquan Zhang and D. Grischkowsky*  

E-print Network

Terahertz Time-Domain Spectroscopy Study of Silica Aerogels and Adsorbed Molecular Vapors Jiangquan time-domain spectroscopy (THz-TDS) study of hydrophobic and hydrophilic silica aerogels, and the adsorption of several molecular vapors in the hydrophilic silica aerogel. The hydrophobic and hydrophilic

406

Two fractal structures in aerogel C. Marliere, T. Woignier *, P. Dieudonne, J. Primera, M. Lamy, J. Phalippou  

E-print Network

Two fractal structures in aerogel C. Marliere, T. Woignier *, P. Dieudonne, J. Primera, M. Lamy, J Montpellier cedex, France Abstract Composite aerogels have been prepared by the addition of silica soot and aerogel structures have been exten- sively studied during the past decade by dierent scattering techniques

Demouchy, Sylvie

407

FTIR ANALYSIS OF AEROGEL KEYSTONES FROM THE STARDUST INTERSTELLAR DUST COLLECTOR: ASSESSMENT OF TERRESTRIAL ORGANIC CONTAMINATION AND X-RAY  

E-print Network

FTIR ANALYSIS OF AEROGEL KEYSTONES FROM THE STARDUST INTERSTELLAR DUST COLLECTOR: ASSESSMENT was composed of aerogel tiles (85% of the collecting area) and aluminum foils and was exposed are expected to be exceedingly small. Here, we present a summary of FTIR analyses of over 20 aerogel keystones

Nittler, Larry R.

408

A NEW VIEW ON INTERSTELLAR DUST HIGH FIDELITY STUDIES OF INTERSTELLAR DUST ANALOGUE TRACKS IN STARDUST FLIGHT SPARE AEROGEL  

E-print Network

IN STARDUST FLIGHT SPARE AEROGEL F. Postberg, C. Allen, S. Bajt, H. A. Bechtel, J. Borg, F. Brenker, J the Stardust Mission exposed aerogel collector panels for a total of about 200 days to the stream - 30km/s] interstellar dust (ISD) analogues onto Stardust aerogel flight spares. This en- ables

409

Ultrasound attenuation measurements in the B-like phase of superfluid 3He embedded in 98% porosity aerogel have been  

E-print Network

aerogel have been performed at four frequencies between 3.6 and 11.3 MHz. At all of the pressures studied. Considering the unique aspects of aerogel originating from its structure, correlation and finite size Ultrasound Attenuation in Superfluid 3He in Aerogel* B.H. Moon, N. Masuhara, P. Bhupathi, M. Gonzalez, M

410

Outdoor high voltage polymeric insulators  

Microsoft Academic Search

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

R. Hackam

1998-01-01

411

High surface area carbon aerogel monoliths with hierarchical porosity  

Microsoft Academic Search

This letter describes the synthesis and structural characterization of monolithic carbon aerogel (CA) materials that possess both high surface areas and hierarchical porosity. Thermal activation of a macroporous CA structure, one that was derived from an acetic acid-catalyzed sol–gel polymerization reaction, yields monolithic materials with large pore volumes and surface areas exceeding 3000m2\\/g. Given the flexibility of CA synthesis, this

Theodore F. Baumann; Marcus A. Worsley; T. Yong-Jin Han; Joe H. Satcher

2008-01-01

412

Characterization of Silica-Containing Aluminum Hydroxide and Oxide Aerogels  

Microsoft Academic Search

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

Marcella Trombetta; Guido Busca; Ronald J. Willey

1997-01-01

413

Synthesis of nanoporous silica aerogel by ambient pressure drying  

Microsoft Academic Search

A crack-free silica aerogel monolith was fabricated from a cheap water glass derived silicic acid solution by adding glycerol,\\u000a which served as a drying control chemical additive (DCCA). The OH surfaces of the wet gel with glycerol were modified using\\u000a a TMCS\\/n-hexane mixture followed by solvent exchange from water to n-hexane. The obtained surface modified wet gel was dried at

Chul Eui Kim; Jong Seol Yoon; Hae Jin Hwang

2009-01-01

414

KOH catalysed preparation of activated carbon aerogels for dye adsorption  

Microsoft Academic Search

Organic carbon aerogels (CAs) were prepared by a sol–gel method from polymerisation of resorcinol, furfural, and hexamethylenetetramine catalysed by KOH at around pH 9 using ambient pressure drying. The effect of KOH in the sol–gel on CA synthesis was studied. It was found that addition of KOH prior to the sol–gel polymerisation process improved thermal stability of the gel, prevented

Sie King Ling; H. Y. Tian; Shaobin Wang; Thomas Rufford; Z. H. Zhu; C. E. Buckley

2011-01-01

415

Carbon aerogel based electrode material for EAP actuators  

NASA Astrophysics Data System (ADS)

In this work we report an actuator material, that consist of carbon aerogel, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) and poly(vinylidene-co-hexafluoropropylene) (PVdF(HFP)). Actuators were made by using layer-by-layer casting method and they work as a bending actuators. Carbon aerogel is synthesized from 5- methylresorcinol, which is a waste product in oil-shale industry. It makes the material "environmentally green". Carbon aerogels have a very low density and considerable specific surface area. It is generally understood that the large interfacial surface area of electrodes gives rise to better actuation performance; therefore, designing actuators with high specific surface area electrodes is of interest. The assembled three layer actuators require low voltage to operate and work steadily in open air due to non-volatile electrolyte. The electromechanical and electrical characteristics of prepared actuators were examined and compared to our previously reported actuators based on the carbide-derived carbon and activated carbon electrodes. The differences in actuation performance were analyzed in the context of pore characteristics and degree of graphitization of carbons. The gas sorption measurements were performed to characterize pore size distribution. These actuators show high strain, low back-relaxation and low power consumption and they are good for slow-response applications compared to carbon nanotube actuators.

Kaasik, Friedrich; Torop, Janno; Peikolainen, Anna-Liisa; Koel, Mihkel; Aabloo, Alvo

2011-04-01

416

Surface Plasmon Resonance Evaluation of Colloidal Metal Aerogel Filters  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

417

Low field NMR in aerogel-confined superfluid ^3He  

NASA Astrophysics Data System (ADS)

The superfluid states of bulk liquid ^3He were convincingly identified through their longitudinal and transverse NMR spectra. The order parameters of the superfluid phases of ^3He confined within aerogel have generally been assumed to be identical to those in bulk liquid. While that identification has not been contradicted by experimental data, it has not yet been tested as carefully as in bulk. Fomin has suggested that the A-like phase in aerogel could be an axiplanar state, distinct from the bulk axial state. We have tested the identification by studying low-field NMR which is more sensitive to the distinction between the candidate states. Using the dc SQUID based NMR detection system developed in our laboratory over many years we have studied both longitudinal and transverse resonance spectra in 99.5% porosity aerogel in magnetic fields of 1-4 mT, an order of magnitude lower than previous NMR work. Our work shows qualitative features similar to those found in higher magnetic fields. While we were unable to resolve the longitudinal resonance, transverse resonance measurements exhibit a characteristic field- and temperature-dependence.

Du, Yuliang; Bozler, H. M.; Gould, C. M.

2008-03-01

418

Ultralow percolation threshold in aerogel and cryogel templated composites.  

PubMed

We demonstrate a novel concept for preparing percolating composites with ultralow filler content by utilizing nanofiller-loaded aerogel and cryogels as a conductive template. This concept is investigated for several porous systems, including resorcinol-formaldehyde (RF), silica, and polyacrylamide (PAM) gels, and both graphene and carbon nanotubes are utilized as nanofiller. In each case, a stable, aqueous nanofiller dispersion is mixed with a sol-gel precursor and polymerized to form a hydrogel, which can then be converted to an aerogel by critical point drying or cryogel by freeze-drying. Epoxy resin is infused into the pores of the gels by capillary action without disrupting the monolithic structure. We show that conductive graphene/epoxy composites are formed with a very low graphene loading; a percolation threshold as low as 0.012 vol % is obtained for graphene-RF cryogel/epoxy composite. This is the lowest reported threshold of any graphene-based nanocomposites. Similar values are achieved in other aerogel and nanofiller systems, which demonstrates the versatility of this method. PMID:23927050

Irin, Fahmida; Das, Sriya; Atore, Francis O; Green, Micah J

2013-09-10

419

Lunar and Planetary Science XXXV: Interplanetary Dust and Aerogel  

NASA Technical Reports Server (NTRS)

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.

2004-01-01

420

Properties of a silica aerogel Cerenkov radiator used in a cosmic ray telescope  

NASA Technical Reports Server (NTRS)

A silica aerogel Cerenkov radiator with a refractive index of 1.06 has been flown in a balloon borne cosmic ray telescope. Clear separation of the elements in the iron group was achieved even at high energies. No detectable scintillation component was found. Some optical properties of the silica aerogel used in this flight are presented.

Cantin, M.; Engelmann, J. J.; Koch, L.; Masse, P.; Lund, N.; Byrnak, B.

1975-01-01

421

Desalting in wastewater reclamation using capacitive deionization with carbon aerogel electrodes  

Microsoft Academic Search

Capacitive deionization with carbon aerogel electrodes is an efficient and economical new process for removing salt and impurities from water. Carbon aerogel is a material that enables the successful purification of water because of its high surface area, optimum pore size, and low electrical resistivity. The electrodes are maintained at a potential difference of about one volt; ions are removed

J. H. Richardson; J. C. Farmer; D. V. Fix; J. A. H. de Pruneda; G. V. Mack; J. F. Poco; J. K. Nielsen; R. W. Pekala

1996-01-01

422

Preparation and characterization of metal-doped carbon aerogel for supercapacitor  

Microsoft Academic Search

Carbon aerogel was prepared by polycondensation of resorcinol and formaldehyde using sodium carbonate as a catalyst with a resorcinol to catalyst ratio of 500. Co-doped carbon aerogels were then prepared by an impregnation method with a variation of cobalt content (1, 3, 5, 7, 10, and 15wt.%), and their performance for supercapacitor electrode was investigated by measurement of specific capacitance

Yoon Jae Lee; Ji Chul Jung; Sunyoung Park; Jeong Gil Seo; Sung-Hyeon Baeck; Jung Rag Yoon; Jongheop Yi; In Kyu Song

2010-01-01

423

Relationship between particle size and magnetoresistance in carbon aerogels prepared under different catalyst conditions  

Microsoft Academic Search

Previous studies of the temperature dependence of the high-field positive magnetoresistance were carried out for carbon aerogels with a fixed [resorcinol]\\/[catalyst] (RC) molar ratio of 200 but different mass densities. The present work focuses on the effect of the particle size on the transport properties of carbon aerogels of both high and low mass densities by varying the RC ratio

A. W. P. Fung; G. A. M. Reynolds; Z. H. Wang; M. S. Dresselhaus; G. Dresselhaus; R. W. Pekala

1995-01-01

424

Study of a proximity focusing RICH with a silica aerogel radiator  

Microsoft Academic Search

A proximity focusing RICH based on a silica aerogel Cherenkov radiator has been developed for a new particle identification device in the upgraded Belle detector. To further improve the detector performance, a new concept for Cherenkov ring imaging has been introduced, where multiple aerogel layers with different indices are accumulated to increase the number of detected photons without making the

I. Adachi; K. Fujita; T. Fukushima; A. Gorisek; D. Hayashi; T. Iijima; T. Ikado; T. Ishikawa; H. Kawai; S. Korpar; Y. Kozakai; P. Krizan; A. Kuratani; Y. Mazuka; T. Nakagawa; S. Nishida; S. Ogawa; R. Pestotnik; T. Seki; T. Sumiyoshi; M. Tabata; Y. Unno

2007-01-01

425

Novel carbon aerogel-supported catalysts for PEM fuel cell application  

Microsoft Academic Search

Novel carbon aerogel supported Pt catalysts with different pore size distributions and Pt content have been synthesized and tested in a proton exchange membrane fuel cell (PEMFC) operation. Characterization of the aerogel supported Pt catalyst has been performed in respect to the total surface area of Pt using HRTEM and BET methods, and was compared to the electrochemical surface area

A. Smirnova; X. Dong; H. Hara; A. Vasiliev; N. Sammes

2005-01-01

426

Reduction in the processing time of doped sodium silicate based ambient pressure dried aerogels using shaker  

Microsoft Academic Search

The experimental results on the “reduction in the processing time of doped sodium silicate based ambient pressure dried aerogels using shaker”, are reported. Shaking the hydrogels in the shaker in presence of distilled water helps in the removal of sodium salt and reduces the processing time of the aerogels. In addition, doping the gels enormously helps in the improvement of

A. Venkateswara Rao; Uzma K. H. Bangi; Mahendra S. Kavale; Hiroaki Imai; H. Hirashima

2010-01-01

427

Assembly of antimony doped tin oxide nanocrystals into conducting macroscopic aerogel monoliths.  

PubMed

We present the assembly of preformed antimony doped tin oxide nanobuilding blocks into centimeter sized aerogels with surface areas exceeding 340 m(2) g(-1). After calcination, the resistivity of the aerogels was decreased by 4 orders of magnitude to a few k? cm, with the primary conducting structures measuring only a few nanometers. PMID:25229075

Rechberger, Felix; Ilari, Gabriele; Niederberger, Markus

2014-10-01

428

Characterisation of biodegradable pectin aerogels and their potential use as drug carriers.  

PubMed

The purpose of this work was to prepare stable citrus (CF) and apple (AF) pectin aerogels for potential pharmaceutical applications. Different shapes of low ester pectin aerogels were prepared by two fundamental methods of ionic cross-linking. Pectins' spherical and multi-membrane gels were first formed by the diffusion method using 0.2M CaCl2 solution as an ionic cross-linker. The highest specific surface area (593m(2)/g) that had so far been reported for pectin aerogels was achieved using this method. Monolithic pectin gels were formed by the internal setting method. Pectin gels were further converted into aerogels by supercritical drying using CO2. As surface area/volume is one of the key parameters in controlling drug release, multi-membrane pectin aerogels were further used as drug delivery carriers. Theophylline and nicotinic acid were used as model drugs for the dissolution study. CF aerogels showed more controlled release behaviour than AF pectin aerogels. Moreover a higher release rate (100%) was observed with CF aerogels. PMID:25256485

Veronovski, Anja; Tkalec, Gabrijela; Knez, Zeljko; Novak, Zoran

2014-11-26

429

Vacuum thermal insulation panel  

Microsoft Academic Search

A vacuum thermal insulation panel comprises a pair of laminated plastic and aluminum sheets together with a plastic edge strip sealed to the edges of the sheets so as to define an evacuable volume in which a glass fiber mat is disposed. The insulation panel of the present invention takes advantage of the light-weight, low cost and low thermal conductivity

J. R. Young; R. M. Schreck

1984-01-01

430

Insulators and Conductors  

NSDL National Science Digital Library

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.

Ieee

2014-05-22

431

Thermal Capacitance Perfect Insulator  

E-print Network

Thermal Capacitance C1 Perfect Insulator Thermal Resistance R1 R3 R2 C2 q Watts q - Temperature qa q2 q1 qb 1. Consider the thermal system shown below. a) Find an equivalent electrical circuit. b) Write out the necessary equations to solve for and .q q1 2 2. A small room is perfectly insulated

Hagan, Martin

432

Transformer insulation life assessment  

Microsoft Academic Search

This paper presents novel techniques for life assessment of the insulation of the generator stepup units in power plants. Load and ambient temperatures are two important factors that influence the life of insulation in transformers. Hourly load and ambient temperatures obtained through condition monitoring are used to assess the operating profile of the equipment. Modeling techniques for estimating load factors

Kshira T. Muthanna; Abhinanda Sarkar; Kaushik Das; Kurt Waldner

2006-01-01

433

Lithium-vanadium advanced blanket development. ITER final report on U.S. contribution: Task T219/T220  

SciTech Connect

The objective of this task is to develop the required data base and demonstrate the performance of a liquid lithium-vanadium advanced blanket design. The task has two main activities related to vanadium structural material and liquid lithium system developments. The vanadium alloy development activity included four subtasks: (1.1) baseline mechanical properties of non irradiated base metal and weld metal joints; (1.2) compatibility with liquid lithium; (1.3) material irradiation tests; and (1.4) development of material manufacturing and joining methods. The lithium blanket technology activity included four subtasks: (2.1) electrical insulation development and testing for liquid metal systems; (2.2) MHD pressure drop and heat transfer study for self-cooled liquid metal systems; (2.3) chemistry of liquid lithium; and (2.4) design, fabrication and testing of ITER relevant size blanket mockups. A summary of the progress and results obtained during the period 1995 and 1996 in each of the subtask areas is presented in this report.

Smith, D.L.; Mattas, R.F. [comps.

1997-07-01

434

Dynamics insulation systems  

NASA Astrophysics Data System (ADS)

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.

Chen, W. E. W.; Hepler, W. A.; Yuan, S. W. K.; Frederking, T. H. K.

1985-10-01

435

Computer modeling of organic aerogels: Final report of 93-SR-062  

SciTech Connect

Goal of the work was to develop computer models of organic aerogel structures, and to study transport process within these materials. During the course of the research understanding of the structure of all aerogels including acid and neutral-catalyzed silica aerogel was developed. The modeling of transport focused on fluid flow in aerogels. We successfully modified a novel state-of-the-art lattice Boltzmann code to simulate flow at low Knudsen number, and developed a simple molecular dynamics code for gas flow at extremely high Knudsen number (low density). These flow-modeling techniques can be used to study aerogel applications for technology transfer; in addition, these techniques can be used to study flow through other porous materials.

Chandler, E.A.; Calef, D.; Ladd, A.J.C.

1994-06-10

436

Aerogel microspheres from natural cellulose nanofibrils and their application as cell culture scaffold.  

PubMed

We demonstrated that ultralight pure natural aerogel microspheres can be fabricated using cellulose nanofibrials (CNF) directly. Experimentally, the CNF aqueous gel droplets, produced by spraying and atomizing through a steel nozzle, were collected into liquid nitrogen for instant freezing followed by freeze-drying. The aerogel microspheres are highly porous with bulk density as low as 0.0018 g cm(-3). The pore size of the cellulose aeogel microspheres ranges from nano- to macrometers. The unique ultralight and high porous structure ensured high moisture (~90 g g(-1)) and water uptake capacity (~100 g g(-1)) of the aerogel microspheres. Covalent cross-linking between the native nanofibrils and cross-linkers made the aerogel microspheres very stable even in a harsh environment. The present study also confirmed this kind of aerogel microspheres from native cellulose fibers can be used as cell culture scaffold. PMID:24894125

Cai, Hongli; Sharma, Sudhir; Liu, Wenying; Mu, Wei; Liu, Wei; Zhang, Xiaodan; Deng, Yulin

2014-07-14

437

Characterization of Dry-Air Aged Granules of Silver-Functionalized Silica Aerogel  

SciTech Connect

This is a letter report to complete level 3 milestone "Assess aging characteristics of silica aerogels" for DOE FCRD program. Recently, samples of Ag0-functionalized silica aerogel were aged in flowing dry air for up to 6 months and then loaded with iodine. This dry-air aging simulated the impact of long-term exposure to process gases during process idling. The 6-month aged sample exhibited an iodine sorption capacity of 32 mass%, which was 9 mass % lower than that for an un-aged Ag0-functionalized silica aerogel. In an attempt to understand this decrease in sorption capacity, we characterized physical properties of the aged samples with Brunauer-Emmett-Teller (BET) nitrogen adsorption, X-ray diffraction (XRD), and high resolution scanning electron microscopy (SEM). The results showed no impact of aging on the aerogel microstructure or the silver nanoparticles in the aerogel, including their spatial distribution and morphology.

Matyas, Josef; Fryxell, Glen E.; Robinson, Matthew J.

2012-09-01

438

Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis  

E-print Network

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.

Tabata, Makoto; Yokobori, Shin-ichi; Kawai, Hideyuki; Takahashi, Jun-ichi; Yano, Hajime; Yamagishi, Akihiko

2011-01-01

439

X-ray radiographic technique for measuring density uniformity of silica aerogel  

E-print Network

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.

Makoto Tabata; Yoshikiyo Hatakeyama; Ichiro Adachi; Takeshi Morita; Keiko Nishikawa

2012-12-14

440

X-ray radiographic technique for measuring density uniformity of silica aerogel  

E-print Network

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.

Tabata, Makoto; Adachi, Ichiro; Morita, Takeshi; Nishikawa, Keiko; 10.1016/j.nima.2012.09.001

2012-01-01

441

A Fluorescent Aerogel for Capture and Identification of Interplanetary and Interstellar Dust  

NASA Technical Reports Server (NTRS)

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.

Dominguez, Gerardo; Westphal, Andrew J.; Phillips, Mark L. F.; Jones, Steven M.

2003-01-01

442

Spacecraft thermal blanket cleaning - Vacuum baking or gaseous flow purging  

NASA Technical Reports Server (NTRS)

The mass losses and the outgassing rates per unit area of three thermal blankets consisting of various combinations of Mylar and Kapton, with interposed Dacron nets, were measured with a microbalance using two methods. The blankets at 25 deg C were either outgassed in vacuum for 20 hours, or were purged with a dry nitrogen flow of 3 cu. ft. per hour at 25 deg C for 20 hours. The two methods were compared for their effectiveness in cleaning the blankets for their use in space applications. The measurements were carried out using blanket strips and rolled-up blanket samples fitting the microbalance cylindrical plenum. Also, temperature scanning tests were carried out to indicate the optimum temperature for purging and vacuum cleaning. The data indicate that the purging for 20 hours with the above N2 flow can accomplish the same level of cleaning provided by the vacuum with the blankets at 25 deg C for 20 hours. In both cases, the rate of outgassing after 20 hours is reduced by 3 orders of magnitude, and the weight losses are in the range of 10E-4 gr/sq cm. Equivalent mass loss time constants, regained mass in air as a function of time, and other parameters were obtained for those blankets.

Scialdone, John J.

1992-01-01

443

Spacecraft thermal blanket cleaning: Vacuum bake of gaseous flow purging  

NASA Technical Reports Server (NTRS)

The mass losses and the outgassing rates per unit area of three thermal blankets consisting of various combinations of Mylar and Kapton, with interposed Dacron nets, were measured with a microbalance using two methods. The blankets at 25 deg C were either outgassed in vacuum for 20 hours, or were purged with a dry nitrogen flow of 3 cu. ft. per hour at 25 deg C for 20 hours. The two methods were compared for their effectiveness in cleaning the blankets for their use in space applications. The measurements were carried out using blanket strips and rolled-up blanket samples fitting the microbalance cylindrical plenum. Also, temperature scanning tests were carried out to indicate the optimum temperature for purging and vacuum cleaning. The data indicate that the purging for 20 hours with the above N2 flow can accomplish the same level of cleaning provided by the vacuum with the blankets at 25 deg C for 20 hours, In both cases, the rate of outgassing after 20 hours is reduced by 3 orders of magnitude, and the weight losses are in the range of 10E-4 gr/sq cm. Equivalent mass loss time constants, regained mass in air as a function of time, and other parameters were obtained for those blankets.

Scialdone, John J.

1990-01-01

444

Emergency control in blanket viability crisis  

SciTech Connect

The viability crisis in a power system is defined, and three consecutive tasks are identified for the viabilizing control. A newly formulated criterion is proposed, and a complete set of approaches for viabilization is presented in both Tasks II and III, an implementable least-disruptive solution is obtained, which ensures that the transient state of the system is in the safe region. A reduced model is introduced which retains the identity in full detail of individual tie lines and of the boundary buses where tie lines connect to the areas but which compresses the details of the areas themselves. The model is useful in blanket emergencies where it facilitates the prediction of the future course of frequency and tie-line loads during the emergency. A load flow program using concentric relaxation and the reduced model is also introduced for fast evaluation of the system state.

Huang, P.

1984-01-01

445

Precipitation behavior in F82H during heat treatments of blanket fabrication  

Microsoft Academic Search

Reduced Activation Ferritic\\/Martensitic steels are leading candidates for the structural material of DEMO blanket module, and they are really used for the ITER test blanket module. During the fabrication process of blanket module, the structural material is exposed to various heat conditions. Microstructural evolutions under the complicated heat history should be focused, because they determine the performance of blanket module.

Hideo Sakasegawa; Hiroyasu Tanigawa; Sho Kano; Masato Enomoto

2011-01-01

446

Biocompatibility of surfactant-templated polyurea-nanoencapsulated macroporous silica aerogels with plasma platelets and endothelial cells.  

PubMed

The recently synthesized polyurea-nanoencapsulated surfactant-templated aerogels (X-aerogels) are porous materials with significantly improved mechanical strengths. Surface-wise they resemble polyurethane, a common biocompatible material, but their biocompatibility has never been investigated. As lightweight and strong materials, if X-aerogels also have acceptable biocompatibility, they may be used in many implantable devices. The goal of this study was to investigate their biocompatibility toward platelets, blood plasma, and vascular endothelial cells, in terms of cell activation and inflammatory responses. Platelets were incubated with X-aerogel and platelet activation was measured through CD62P and phosphatidylserine expression. Platelet aggregation was also measured. Contact with X-aerogel did not induce platelet activation or impair aggregation. To determine X-aerogel-induced inflammation, plasma anaphylatoxin C3a level was measured after incubation with X-aerogel. Results showed that X-aerogel induced no changes in plasma C3a levels. SEM and SDS-PAGE were used to examine cellular/protein deposition on X-aerogel samples after plasma incubation. No structural change or organic deposition was detected. Furthermore, X-aerogel samples did not induce any significant changes in vascular endothelial cell culture parameters after 5 days of incubation. These observations suggest that X-aerogels have a suitable biocompatibility toward platelets, plasma, and vascular endothelial cells, and they have potential for use in blood implantable devices. PMID:19358258

Yin, Wei; Venkitachalam, Subramaniam M; Jarrett, Ellen; Staggs, Sarah; Leventis, Nicholas; Lu, Hongbing; Rubenstein, David A

2010-03-15

447

Development of fusion blanket technology for the DEMO reactor.  

PubMed

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

Colling, B R; Monk, S D

2012-07-01

448

Insulation fact sheet  

SciTech Connect

Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.

NONE

1997-08-01

449

Pipe Insulation Economies  

E-print Network

simply K-f actor) is used. Although there are too many variables for "K" to be a precise definition of an intrinsic property of insulation, it is generally the most practical way to define the character istics of an insulation. An important variable... or corrosive atmospheres; ? Assist mechanical systems in meeting USDA (FDA) criteria in food and cosmetic plants. The temperature range within which the insula tion will operate is normally between -150 0 F and 1500 0 F. Thermal insulation is divided...

Schilling, R. E.

450

Cryogenic insulation development  

NASA Technical Reports Server (NTRS)

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.

Leonhard, K. E.

1972-01-01

451

Internal insulation system development  

NASA Technical Reports Server (NTRS)

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.

Gille, J. P.

1973-01-01

452

Blast venting through blanket material in the HYLIFE ICF reactor  

SciTech Connect

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 delivered to the protective liquid blanket. Configurations used in the study include both 2700 MJ and 350 MJ fusion yields per pulse for 5 meter and 3 meter radius reactor chambers. For the former, an annular jet array is used for the blanket geometry, while in the latter, both annular jet array as well as slab geometries are used. Results of the study indicate that blast venting and wall loading may be manageable in the HYLIFE-II design by a judicious choice of blanket configuration.

Liu, J.C.; Peterson, P.F.; Schrock, V.E. [California Univ., Berkeley, CA (United States). Dept. of Nuclear Engineering

1992-03-10

453

Fusion blanket for high-efficiency power cycles  

SciTech Connect

The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperature (500/sup 0/C) of conventional structural materials such as stainless steels. In this project two-zone blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO/sub 2/ interior (cooled by Ar) utilizing Li/sub 2/O for tritium breeding. In this design, approx. 60% of the fusion energy is deposited in the high-temperature interior. The maximum Ar temperature is 2230/sup 0/C leading to an overall efficiency estimate of 55 to 60% for this reference case.

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

1980-01-01

454

A Solid breeder tokamak blanket designed for failure mode operation  

E-print Network

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 ...

Chen, Franklin Fun Kun

1977-01-01

455

Blanket options for high-efficiency fusion power  

SciTech Connect

The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperatures (500/sup 0/C) of conventional structural materials such as stainless steels. In this project two-zone blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO/sub 2/ interior (cooled by argon) utilizing Li/sub 2/O for tritium breeding. In this design, approximately 60% of the fusion energy is deposited in the high-temperature interior. The maximum argon temperature is 2230/sup 0/C leading to an overall efficiency estimate of 55 to 60% for this reference case.

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

1980-01-01

456

Outdoor HV composite polymeric insulators  

Microsoft Academic Search

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

R. Hackam

1999-01-01

457

Cooper Pairs in Insulators?!  

SciTech Connect

Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

James Valles

2008-07-23

458

Cooper Pairs in Insulators?!  

SciTech Connect

Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions.

Valles, James (Brown University) [Brown University

2008-07-23

459

Cooper Pairs in Insulators?!  

ScienceCinema

Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

James Valles

2010-01-08

460

Vacuum thermal insulation panel  

SciTech Connect

A vacuum thermal insulation panel comprises a pair of laminated plastic and aluminum sheets together with a plastic edge strip sealed to the edges of the sheets so as to define an evacuable volume in which a glass fiber mat is disposed. The insulation panel of the present invention takes advantage of the light-weight, low cost and low thermal conductivity of plastic materials to form an evacuable volume into which a glass fiber insulating mat is disposed for support of the panel which is evacuated to provide improved thermal insulation. Additionally, a gas permeation barrier is employed on the edge strip of the panel to minimize gas permeation at its edges. A metal foil layer provides gas permeation protection through the large surface areas of the sheets themselves.

Young, J.R.; Schreck, R.M.

1984-04-24

461

Membranes Improve Insulation Efficiency  

E-print Network

It has been determined from extensive tests involving test models and home attics that loose fill and fiber batt insulation does not function as expected by the industry. The reason for this deficiency is current test methods do not accurately...

Bullock, C. A.

1986-01-01

462

Applications of the Aqueous Self-Cooled Blanket concept  

Microsoft Academic Search

In this paper a novel water-cooled blanket concept is examined. This concept, designated the Aqueous Self-Cooled Blanket (ASCB), employs water with small amounts of dissolved fertile compounds as both the coolant and the breeding medium. The ASCB concept is reviewed and its application in three different contexts is examined: (1) power reactors; (2) near-term devices such as NET; and (3)

D. Steiner; M. J. Embrechts; G. Varsamis; K. Wrisley; L. Deutch; P. Gierszewski

1986-01-01

463

Improved Sprayable Insulation  

NASA Technical Reports Server (NTRS)

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.

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

464

Thermal Insulation Systems  

E-print Network

. The original formulation was a complete inorganic material containing about 15% asbestos fiber. No organ c binders are required for physical integrity. The insulation has fair thermal properties and, is available in pipe covering and block forms; density.... The original formulation was a complete inorganic material containing about 15% asbestos fiber. No organ c binders are required for physical integrity. The insulation has fair thermal properties and, is available in pipe covering and block forms; density...

Stanley, T. F.

1982-01-01

465

Inorganic hollow nanotube aerogels by atomic layer deposition onto native nanocellulose templates.  

PubMed

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

Korhonen, Juuso T; Hiekkataipale, Panu; Malm, Jari; Karppinen, Maarit; Ikkala, Olli; Ras, Robin H A

2011-03-22

466

Preparation and characterization of Cu:SiO 2 aerogel films  

NASA Astrophysics Data System (ADS)

This paper examines the effect of the amount of Cu(II) cations and modifiers on the physical properties of Cu:SiO 2 aerogels. The Cu:SiO 2 aerogel films were also synthesized by a copolymerization sol-gel reaction, followed by ambient drying. Among the three surface modifiers (TMCS, MTMS, and HMDSZ) that were examined, the HMDSZ was found to be effective regarding stability and properties. The Cu:SiO 2 aerogel films were found to have a high surface area of (>770 m 2/g), an average pore diameter of 2.8˜3.6 nm, and crack-free blue colored aerogels. 1˜2 mol% Cu:SiO 2 aerogel films showed a high transmittance of over 90%. The resulting Cu:SiO 2 aerogel composites were characterized by SEM/EDS, BET, TG-DSC, UV-VIS-NIR, and TEM observation. The Cu(II) cations interrupted the spring back effect of the Cu:SiO 2 wet gel during gelation. CuO nano particles with an average of 20 nm were dispersed in the SiO 2 aerogel film, which was fired at 300 °C.

Oh, Young-Jei; Nam, Bo-Ae

2011-08-01

467

Graphite aerogels and the formation mechanism of unusual micron-size rod and helical structures  

NASA Astrophysics Data System (ADS)

Pyrolysis at 800 °C under argon has shown that polyimide (PI), polyacrylonitrile (PAN), polydicyclopentadiene (DCPD) and polybenzoxazine (PBO) aerogels are all viable alternatives to traditional resorcinol-formaldehyde (RF) aerogels as precursors to amorphous carbon aerogels. Subsequent high temperature pyrolysis at 2300 °C of such carbon aerogels under helium has shown that amorphous carbon from PI and PBO yields the highest degree of graphitization, whereas from RF aerogels yields the lowest. Those two types of graphite aerogels include also a high concentration of micron-size columnar and helical (screw-like) structures, whose formation is favored by macroporosity and high nitrogen retention in the 800 °C-carbonized samples. Control experiments were conducted with corannulene and bromo-corannulene in order to integrate cyclopentyl rings on surfaces of activated carbon, PBO-derived carbon aerogels, and carbon black. In most cases the concentration of rod and helical structures increased dramatically (over 50%). An idealized growth model was formulated for the formation of the rods and screw-like structures, whereas rapid grain growth leads to the formation of cyclopentyl rings and disclinations in the graphitic network. Trivalent nitrogen, when present, assists in the developed of cyclopentyl rings and subsequent growth of the columnar carbon structures.

Wisner, Clarissa Ann

468

Refractory nanoporous materials fabricated using tungsten atomic layer deposition on silica aerogels  

NASA Astrophysics Data System (ADS)

We report an approach for preparing refractory nanoporous materials using high surface area silica aerogels as templates for the growth of conformal tungsten (W) coatings by atomic layer deposition (ALD). Nanoporous silica aerogel monoliths were prepared with a variety of initial pore sizes and initial densities in the range of 0.3-0.5 g/cc using porogen extraction methods. Next, W ALD using Si2H6 and WF6 reactants at 200 °C was employed to coat the inner surfaces of the silica aerogels. After coating, scanning electron microscopy revealed a microstructure in which the ALD W completely encapsulated the silica aerogel micro-cells. The porosity of the aerogels was preserved during the first 10 W ALD cycles allowing the density to be controlled by adjusting the number of W ALD cycles to achieve densities as high as 5 g/cc. Nitrogen adsorption surface area measurements revealed a gradual decrease in the surface area of the silica aerogels with increasing numbers of W ALD cycles, consistent with a partial filling of the aerogel voids. The high density nanoporous tungsten monoliths survived high temperature vacuum heating (1500 °C) making them promising candidates for solid rare-isotope catchers that can be used in the production of short-lived radioactive isotope beams in facilities such as the facility for rare isotope beams (FRIB).

Mane, Anil U.; Greene, John P.; Nolen, Jerry A.; Sampathkumaran, Uma; Owen, Thomas W.; Winter, Ray; Elam, Jeffrey W.

2012-06-01

469

Iron-oxide aerogel and xerogel catalyst formulations: Characterization by 57Fe Mössbauer and XAFS spectroscopies  

NASA Astrophysics Data System (ADS)

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.

Huggins, Frank E.; Bali, Sumit; Huffman, Gerald P.; Eyring, Edward M.

2010-06-01

470

Simplified procedure for encapsulating cytochrome c in silica aerogel nanoarchitectures while retaining gas-phase bioactivity.  

PubMed

Cytochrome c (cyt. c) has been encapsulated in silica sol-gels and processed to form bioaerogels with gas-phase activity for nitric oxide through a simplified synthetic procedure. Previous reports demonstrated a need to adsorb cyt. c to metal nanoparticles prior to silica sol-gel encapsulation and processing to form aerogels. We report that cyt. c can be encapsulated in aerogels without added nanoparticles and retain structural stability and gas-phase activity for nitric oxide. While the UV-visible Soret absorbance and nitric oxide response indicate that cyt. c encapsulated with nanoparticles in aerogels remains slightly more stable and functional than cyt. c encapsulated alone, these properties are not very different in the two types of aerogels. From UV-visible and Soret circular dichroism results, we infer that cyt. c encapsulated alone self-organizes to reduce contact with the silica gel in a way that may bear at least some resemblance to the way cyt. c self-organizes into superstructures of protein within aerogels when nanoparticles are present. Both the buffer concentration and the cyt. c concentration of solutions used to synthesize the bioaerogels affect the structural integrity of the protein encapsulated alone within the dried aerogels. Optimized bioaerogels are formed when cyt. c is encapsulated from 40 mM phosphate buffered solutions, and when the loaded cyt. c concentration in the aerogel is in the range of 5 to 15 ?M. Increased viability of cyt. c in aerogels is also observed when supercritical fluid used to produce aerogels is vented over relatively long times. PMID:22924640

Harper-Leatherman, Amanda S; Iftikhar, Mariam; Ndoi, Adela; Scappaticci, Steven J; Lisi, George P; Buzard, Kaitlyn L; Garvey, Elizabeth M

2012-10-16

471

Multifunctional structural supercapacitor composites based on carbon aerogel modified high performance carbon fiber fabric.  

PubMed

A novel multifunctional material has been designed to provide excellent mechanical properties while possessing a high electrochemical surface area suitable for electrochemical energy storage: structural carbon fiber fabrics are embedded in a continuous network of carbon aerogel (CAG) to form a coherent but porous monolith. The CAG-modification process was found to be scalable and to be compatible with a range of carbon fiber fabrics with different surface properties. The incorporation of CAG significantly increased the surface area of carbon fiber fabrics, and hence the electrochemical performance, by around 100-fold, resulting in a CAG-normalized specific electrode capacitance of around 62 F g(-1), determined by cyclic voltammetry in an aqueous electrolyte. Using an ionic liquid (IL) electrolyte, the estimated energy density increased from 0.003 to 1 Wh kg(-1), after introducing the CAG into the carbon fiber fabric. 'Proof-of-concept' multifunctional structural supercapacitor devices were fabricated using an IL-modified solid-state polymer electrolyte as a multifunctional matrix to provide both ionic transport and physical support for the primary fibers. Two CAG-impregnated carbon fabrics were sandwiched around an insulating separator to form a functioning structural electrochemical double layer capacitor composite. The CAG-modification not only improved the electrochemical surface area, but also reinforced the polymer matrix surrounding the primary fibers, leading to dramatic improvements in the matrix-dominated composite properties. Increases in in-plane shear strength and modulus, of up to 4.5-fold, were observed, demonstrating that CAG-modified structural carbon fiber fabrics have promise in both pure structural and multifunctional energy storage applications. PMID:23668320

Qian, Hui; Kucernak, Anthony R; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

2013-07-10

472

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

SciTech Connect

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.

Hamm, L.L.

1998-10-07

473

Decomposition of 4-phenoxyphenol to aromatics over palladium catalyst supported on activated carbon aerogel  

Microsoft Academic Search

Carbon aerogel (CA) was prepared by a sol–gel polymerization of resorcinol and formaldehyde, and a series of activated carbon aerogels (ACA-H3PO4-X, X=0, 0.5, 1.0, 2.0, and 3.0) were prepared by a chemical activation using different amount of phosphoric acid (X represented weight ratio of H3PO4 with respect to CA). Palladium catalysts were then supported on activated carbon aerogels (Pd\\/ACA-H3PO4-X, X=0,

Hai Woong Park; Ung Gi Hong; Yoon Jae Lee; In Kyu Song

474

Mineralization of clay/polymer aerogels: a bioinspired approach to composite reinforcement.  

PubMed

Clay aerogels, ultra low density materials made via a simple freeze-drying technique, have shown much promise in broad applications because of their low densities, often in the same range as silica aerogels (0.03-0.3 g/cm(3),) but suffering from low mechanical strength. A bioinspired approach to mineralize an active polymer/clay aerogel composite is inspected, showing marked improvement of the mechanical properties with increasing modification. Further property improvement was achieved using a layer-by-layer approach to produce alternate layers of polymer and silica on the surface. PMID:20355926

Johnson, Jack R; Spikowski, Jane; Schiraldi, David A

2009-06-01