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1

Aerogel Blanket Insulation Materials for Cryogenic Applications  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

2

Improved Aerogel Vacuum Thermal Insulation  

NASA Technical Reports Server (NTRS)

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

Ruemmele, Warren P.; Bue, Grant C.

2009-01-01

3

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

E-print Network

Evacuated Panels Utilizing Clay-Polymer Aerogel Composites for Improved Housing Insulation March 17 encompasses a newly developed clay-polymer aerogel composite material (developed and patented by Dr. David Aerogel ~22 > 2,500 Silica Aerogel Blanket 10 1,800 (Aspen Aerogel) Silica Aerogel / PP Evacuated Panel 50

Rollins, Andrew M.

4

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

5

Thermal insulation blanket material  

NASA Technical Reports Server (NTRS)

A study was conducted to provide a tailorable advanced blanket insulation based on a woven design having an integrally woven core structure. A highly pure quartz yarn was selected for weaving and the cells formed were filled with a microquartz felt insulation.

Pusch, R. H.

1982-01-01

6

Aerogels Insulate Against Extreme Temperatures  

NASA Technical Reports Server (NTRS)

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

2010-01-01

7

Thermal insulating conformal blanket  

NASA Technical Reports Server (NTRS)

The conformal thermal insulating blanket may have generally rigid batting material covered by an outer insulating layer formed of a high temperature resistant woven ceramic material and an inner insulating layer formed of a woven ceramic fiber material. The batting and insulating layers may be fastened together by sewing or stitching using an outer mold layer thread fabricated of a high temperature resistant material and an inner mold layer thread of a ceramic fiber material. The batting may be formed to a composite structure that may have a firmness factor sufficient to inhibit a pillowing effect after the stitching to not more than 0.03 inch. The outer insulating layer and an upper portion of the batting adjacent the outer insulating layer may be impregnated with a ceramic coating material.

Barney, Andrea (Inventor); Whittington, Charles A (Inventor); Eilertson, Bryan (Inventor); Siminski, Zenon (Inventor)

2003-01-01

8

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

9

Hybrid Multifoil Aerogel Thermal Insulation  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

10

Thermal Performance Testing of Order Dependancy of Aerogels Multilayered Insulation  

NASA Technical Reports Server (NTRS)

Robust multilayer insulation systems have long been a goal of many research projects. Such insulation systems must provide some degree of structural support and also mechanical integrity during loss of vacuum scenarios while continuing to provide insulative value to the vessel. Aerogel 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 (MU) 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 and multilayer insulation systems have been tested at Cryogenics Test Laboratory of NASA Kennedy Space Center. Analysis performed at Oak Ridge National Laboratory showed an importance to the relative location of the MU and aerogel blankets. Apparent thermal conductivity testing under cryogenic-vacuum 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, Wesley L.; Fesmire, James E.; Demko, J. A.

2009-01-01

11

Polyimide-Foam/Aerogel Composites for Thermal Insulation  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

12

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

13

Aerogels Insulate Missions and Consumer Products  

NASA Technical Reports Server (NTRS)

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

2008-01-01

14

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

15

Aerogels for Thermal Insulation of Thermoelectric Devices  

NASA Technical Reports Server (NTRS)

Silica aerogels have been shown to be attractive for use as thermal-insulation materials for thermoelectric devices. It is desirable to thermally insulate the legs of thermoelectric devices to suppress lateral heat leaks that degrade thermal efficiency. Aerogels offer not only high thermal- insulation effectiveness, but also a combination of other properties that are especially advantageous in thermoelectric- device applications. Aerogels are synthesized by means of sol-gel chemistry, which is ideal for casting insulation into place. As the scale of the devices to be insulated decreases, the castability from liquid solutions becomes increasingly advantageous: By virtue of castability, aerogel insulation can be made to encapsulate devices having any size from macroscopic down to nanoscopic and possibly having complex, three-dimensional shapes. Castable aerogels can permeate voids having characteristic dimensions as small as nanometers. Hence, practically all the void space surrounding the legs of thermoelectric devices could be filled with aerogel insulation, making the insulation highly effective. Because aerogels have the lowest densities of any known solid materials, they would add very little mass to the encapsulated devices. The thermal-conductivity values of aerogels are among the lowest reported for any material, even after taking account of the contributions of convection and radiation (in addition to true thermal conduction) to overall effective thermal conductivities. Even in ambient air, the contribution of convection to effective overall thermal conductivity of an aerogel is extremely low because of the highly tortuous nature of the flow paths through the porous aerogel structure. For applications that involve operating temperatures high enough to give rise to significant amounts of infrared radiation, opacifiers could be added to aerogels to reduce the radiative contributions to overall effective thermal conductivities. One example of an opacifier is carbon black, which absorbs infrared radiation. Another example of an opacifier is micron- sized metal flakes, which reflect infrared radiation. Encapsulation in cast aerogel insulation also can help prolong the operational lifetimes of thermoelectric devices that must operate in vacuum and that contain SiGe or such advanced skutterudite thermoelectric materials as CoSb3 and CeFe3.5Co0.5Sb12. The primary cause of deterioration of most thermoelectric materials is thermal decomposition or sublimation (e.g., sublimation of Sb from CoSb3) at typical high operating temperatures. Aerogel present near the surface of CoSb3 can impede the outward transport of Sb vapor by establishing a highly localized, equilibrium Sb vapor atmosphere at the surface of the CoSb3.

Sakamoto, Jeffrey; Fleurial, Jean-Pierre; Snyder, Jeffrey; Jones, Steven; Caillat, Thierry

2006-01-01

16

Nonflammable, Hydrophobic Aerogel Composites for Insulation  

NASA Technical Reports Server (NTRS)

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

Redouane, Begag

2005-01-01

17

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

18

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.

2014-06-10

19

Aerogel insulation systems for space launch applications  

NASA Astrophysics Data System (ADS)

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, J. E.

2006-02-01

20

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

21

Method of fabricating a multilayer insulation blanket  

DOEpatents

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

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

1993-01-01

22

Method of fabricating a multilayer insulation blanket  

DOEpatents

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

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

1993-07-06

23

Multilayer insulation blanket, fabricating apparatus and method  

DOEpatents

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

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

1992-01-01

24

Multilayer insulation blanket, fabricating apparatus and method  

DOEpatents

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

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

1992-09-01

25

Insulation Blankets for High-Temperature Use  

NASA Technical Reports Server (NTRS)

Insulating blanket resists temperatures up to 1,500 degrees F (815 degrees C). Useful where high-temperature resistance, flexibility, and ease of installation are important - for example, insulation for odd-shaped furnaces and high-temperature ducts, curtains for furnace openings and fire control, and conveyor belts in hot processes. Blanket is quilted composite consisting of two face sheets: outer one of silica, inner one of silica or other glass cloth with center filling of pure silica glass felt sewn together with silica glass threads.

Goldstein, H.; Leiser, D.; Sawko, P. M.; Larson, H. K.; Estrella, C.; Smith, M.; Pitoniak, F. J.

1986-01-01

26

Nanogel Aerogel as Load Bearing Insulation for Cryogenic Systems  

NASA Astrophysics Data System (ADS)

Load support structures in cryogenic storage, transport and processing systems are large contributors to the total heat leak of the system. Conventional insulation systems require the use of these support members in order to stabilize the process fluid enclosure and prevent degradation of insulation performance due to compression. Removal of these support structures would substantially improve system efficiency. Nanogel aerogel insulation performance is tested at vacuum pressures ranging from high vacuum to atmospheric pressure and under loads from loosely packed to greater than 10,000 Pa. Insulation performance is determined using boil-off calorimetry with liquid nitrogen as the latent heat recipient. Two properties of the aerogel insulation material suit it to act as a load bearing "structure" in a process vessel: (1) Ability to maintain thermal performance under load; (2) Elasticity when subjected to load. Results of testing provide positive preliminary indication that these properties allow Nanogel aerogel to effectively be used as a load bearing insulation in cryogenic systems.

Koravos, J. J.; Miller, T. M.; Fesmire, J. E.; Coffman, B. E.

2010-04-01

27

Aerogel Insulation Applications for Liquid Hydrogen Launch Vehicle Tanks  

NASA Technical Reports Server (NTRS)

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

Fesmire, J. E.; Sass, J.

2007-01-01

28

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

29

Lightweight and thermally insulating aerogel glass materials  

NASA Astrophysics Data System (ADS)

Glass represents an important and widely used building material, and crucial aspects to be addressed include thermal conductivity, visible light transmittance, and weight for windows with improved energy efficiency. In this work, by sintering monolithic silica aerogel precursors at elevated temperatures, aerogel glass materials were successfully prepared, which were characterized by low thermal conductivity [k ? 0.17-0.18 W/(mK)], high visible transparency (T vis ? 91-96 % at 500 nm), low density (? ? 1.60-1.79 g/cm3), and enhanced mechanical strength (typical elastic modulus E r ? 2.0-6.4 GPa). These improved properties were derived from a series of successive gelation and aging steps during the desiccation of silica aerogels. The involved sol ? gel ? glass transformation was investigated by means of thermo-gravimetric analysis, scanning electron microscopy, nanoindentation, and Fourier transform infrared spectroscopy. Strategies of improving further the mechanical strength of the obtained aerogel glass materials are also discussed.

Gao, Tao; Jelle, Bjørn Petter; Gustavsen, Arild; He, Jianying

2014-07-01

30

Process for forming transparent aerogel insulating arrays  

DOEpatents

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

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

1985-09-04

31

Process for forming transparent aerogel insulating arrays  

DOEpatents

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

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

1986-01-01

32

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

33

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

34

Advanced Polymer For Multilayer Insulating Blankets  

NASA Technical Reports Server (NTRS)

Polymer resisting degradation by monatomic oxygen undergoing commercial development under trade name "Aorimide" ("atomic-oxygen-resistant imidazole"). Intended for use in thermal blankets for spacecraft in low orbit, useful on Earth in outdoor applications in which sunlight and ozone degrades other plastics. Also used, for example, to make threads and to make films coated with metals for reflectivity.

Haghighat, R. Ross; Shepp, Allan

1996-01-01

35

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

NASA Technical Reports Server (NTRS)

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

Ou, Danny; Trifu, Roxana; Caggiano, Gregory

2013-01-01

36

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

37

Tailorable advanced blanket insulation using aluminoborosilicate and alumina batting  

NASA Technical Reports Server (NTRS)

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

Calamito, Dominic P.

1989-01-01

38

Tailorable advanced blanket insulation using aluminoborosilicate and alumina batting  

SciTech Connect

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

Calamito, D.P.

1989-07-01

39

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

40

Polymethylsilsesquioxane-cellulose nanofiber biocomposite aerogels with high thermal insulation, bendability, and superhydrophobicity.  

PubMed

Polymethylsilsesquioxane-cellulose nanofiber (PMSQ-CNF) composite aerogels have been prepared through sol-gel in a solvent containing a small amount of CNFs as suspension. Since these composite aerogels do not show excessive aggregation of PMSQ and CNF, the original PMSQ networks are not disturbed. Composite aerogels with low density (0.020 g cm(-3) at lowest), low thermal conductivity (15 mW m(-1) K(-1)), visible light translucency, bending flexibility, and superhydrophobicity thus have been successfully obtained. In particular, the lowest density and bending flexibility have been achieved with the aid of the physical supporting effect of CNFs, and the lowest thermal conductivity is comparable with the original PMSQ aerogels and standard silica aerogels. The PMSQ-CNF composite aerogels would be a candidate to practical high-performance thermal insulating materials. PMID:24865571

Hayase, Gen; Kanamori, Kazuyoshi; Abe, Kentaro; Yano, Hiroyuki; Maeno, Ayaka; Kaji, Hironori; Nakanishi, Kazuki

2014-06-25

41

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

PubMed

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

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

2013-10-15

42

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

43

Sorption Properties of Aerogel in Liquid Nitrogen  

NASA Technical Reports Server (NTRS)

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

Johnson, Wesley L.

2006-01-01

44

"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

45

Polyolefin-Based Aerogels  

NASA Technical Reports Server (NTRS)

An organic polybutadiene (PB) rubberbased aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection, exhibiting the flexibility, resiliency, toughness, and durability typical of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. The rubbery behaviors of the PB rubber-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogel insulation materials. Additionally, with higher content of hydrogen in their structure, the PB rubber aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. Since PB rubber aerogels also exhibit good hydrophobicity due to their hydrocarbon molecular structure, they will provide better performance reliability and durability as well as simpler, more economic, and environmentally friendly production over the conventional silica or other inorganic-based aerogels, which require chemical treatment to make them hydrophobic. Inorganic aerogels such as silica aerogels demonstrate many unusual and useful properties. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven one promising approach, providing a conveniently fielded form factor that is relatively robust toward handling in industrial environments compared to silica aerogel monoliths. However, the flexible silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain applications. Although the cross-linked organic aerogels such as resorcinol-formaldehyde (RF), polyisocyanurate, and cellulose aerogels show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient radiation shielding materials due to their lower content of hydrogen element. The present invention relates to maleinized polybutadiene (or polybutadiene adducted with maleic anhydride)- based aerogel monoliths and composites, and the methods for preparation. Hereafter, they are collectively referred to as polybutadiene aerogels. Specifically, the polybutadiene aerogels of the present invention are prepared by mixing a maleinized polybutadiene resin, a hardener containing a maleic anhydride reactive group, and a catalyst in a suitable solvent, and maintaining the mixture in a quiescent state for a sufficient period of time to form a polymeric gel. After aging at elevated temperatures for a period of time to provide uniformly stronger wet gels, the micro porous maleinized polybutadiene- based aerogel is then obtained by removing interstitial solvent by supercritical drying. The mesoporous maleinized polybutadiene-based aerogels contain an open-pore structure, which provides inherently hydrophobic, flexible, nearly unbreakable, less dusty aerogels with excellent thermal and physical properties. The materials can be used as thermal and acoustic insulation, radiation shielding, and vibration-damping materials. The organic PB-based rubber aerogels are very flexible, no-dust, and hydrophobic organics that demonstrated the following ranges of typical properties: densities of 0.08 to 0.255 grams per cubic centimeters, shrinkage factor (raerogel/rtarget) = 1.2 to 2.84, and thermal conductivity values of 20.0 to 35.0 mW/m-K.

Lee, Je Kyun; Gould, George

2012-01-01

46

Aerogels with 3D ordered nanofiber skeletons of liquid-crystalline nanocellulose derivatives as tough and transparent insulators.  

PubMed

Aerogels of high porosity and with a large internal surface area exhibit outstanding performances as thermal, acoustic, or electrical insulators. However, most aerogels are mechanically brittle and optically opaque, and the structural and physical properties of aerogels strongly depend on their densities. The unfavorable characteristics of aerogels are intrinsic to their skeletal structures consisting of randomly interconnected spherical nanoparticles. A structurally new type of aerogel with a three-dimensionally ordered nanofiber skeleton of liquid-crystalline nanocellulose (LC-NCell) is now reported. This LC-NCell material is composed of mechanically strong, surface-carboxylated cellulose nanofibers dispersed in a nematic LC order. The LC-NCell aerogels are transparent and combine mechanical toughness and good insulation properties. These properties of the LC-NCell aerogels could also be readily controlled. PMID:24985785

Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

2014-09-22

47

Evaluation of Impact Craters on Thermal Multi-Layer-Insulation (MLI) Blankets  

E-print Network

Evaluation of Impact Craters on Thermal Multi-Layer-Insulation (MLI) Blankets ESA / ESTEC PO 142355........................................................................................ 7 Determination of Impact Crater Characteristics....................................................................... 10 Investigation of the Crater - Impact Relationship

48

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

49

Polyurea based aerogel for a high performance thermal insulation material  

Microsoft Academic Search

Less fragile lightweight nanostructured polyurea based organic aerogels were prepared via a simple sol–gel processing and\\u000a supercritical drying method. The uniform polyurea wet gels were first prepared at room temperature and atmospheric pressure\\u000a by reacting different isocyanates with polyamines using a tertiary amine (triethylamine) catalyst. Gelation kinetics, uniformity\\u000a of wet gel, and properties of aerogel products were significantly affected by

Je Kyun Lee; George L. Gould; Wendell Rhine

2009-01-01

50

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

51

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

52

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

53

Composite, Cryogenic, Conformal, Common Bulkhead, Aerogel-Insulated Tank (CBAT) Materials and Processing Methodologies  

NASA Technical Reports Server (NTRS)

A viewgraph presentation outlines the current status and future activities of the composite, cryogenic, conformal, common bulkhead, aerogel-insulated tank (CBAT). Each term (composite, cryogenic, conformal, etc.) is explained. The fabrication method for the CBAT is described, including challenges and their solutions. Near term and long term goals are discussed.

Kovach, Michael P.; Roberts, J. Keith; Finckenor, Jeffrey L.; McMahon, William M.; Clinton, R. G., Jr. (Technical Monitor)

2000-01-01

54

Silicon Oxycarbide Aerogels for High-Temperature Thermal Insulation  

NASA Technical Reports Server (NTRS)

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

Evans, Owen; Rhine, Wendell; Coutinho, Decio

2010-01-01

55

Polyurea-Based Aerogel Monoliths and Composites  

NASA Technical Reports Server (NTRS)

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

Lee, Je Kyun

2012-01-01

56

Silica/Polymer and Silica/Polymer/Fiber Composite Aerogels  

NASA Technical Reports Server (NTRS)

Aerogels that consist, variously, of neat silica/polymer alloys and silica/polymer alloy matrices reinforced with fibers have been developed as materials for flexible thermal-insulation blankets. In comparison with prior aerogel blankets, these aerogel blankets are more durable and less dusty. These blankets are also better able to resist and recover from compression . an important advantage in that maintenance of thickness is essential to maintenance of high thermal-insulation performance. These blankets are especially suitable as core materials for vacuum- insulated panels and vacuum-insulated boxes of advanced, nearly seamless design. (Inasmuch as heat leakage at seams is much greater than heat leakage elsewhere through such structures, advanced designs for high insulation performance should provide for minimization of the sizes and numbers of seams.) A silica/polymer aerogel of the present type could be characterized, somewhat more precisely, as consisting of multiply bonded, linear polymer reinforcements within a silica aerogel matrix. Thus far, several different polymethacrylates (PMAs) have been incorporated into aerogel networks to increase resistance to crushing and to improve other mechanical properties while minimally affecting thermal conductivity and density. The polymethacrylate phases are strongly linked into the silica aerogel networks in these materials. Unlike in other organic/inorganic blended aerogels, the inorganic and organic phases are chemically bonded to each other, by both covalent and hydrogen bonds. In the process for making a silica/polymer alloy aerogel, the covalent bonds are introduced by prepolymerization of the methacrylate monomer with trimethoxysilylpropylmethacrylate, which serves as a phase cross-linker in that it contains both organic and inorganic monomer functional groups and hence acts as a connector between the organic and inorganic phases. Hydrogen bonds are formed between the silanol groups of the inorganic phase and the carboxyl groups of the organic phase. The polymerization process has been adapted to create interpenetrating PMA and silica-gel networks from monomers and prevent any phase separations that could otherwise be caused by an overgrowth of either phase. Typically, the resulting PMA/silica aerogel, without or with fiber reinforcement, has a density and a thermal conductivity similar to those of pure silica aerogels. However, the PMA enhances mechanical properties. Specifically, flexural strength at rupture is increased to 102 psi (=0.7 MPa), about 50 times the flexural strength of typical pure silica aerogels. Resistance to compression is also increased: Applied pressure of 17.5 psi (=0.12 MPa) was found to reduce the thicknesses of several composite PMA/silica aerogels by only about 10 percent.

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

2010-01-01

57

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

58

Aerogel applications  

Microsoft Academic Search

Aerogel materials possess a wide variety of exceptional properties, hence a striking number of applications have developed for them. Many of the commercial applications of aerogels such as catalysts, thermal insulation, windows, and particle detectors are under development and new applications have been publicized since the ISA4 Conference in 1994: e.g., supercapacitors, insulation for heat storage in automobiles, electrodes for

Lawrence W. Hrubesh

1998-01-01

59

Thermal blanket insulation for advanced space transportation systems  

NASA Technical Reports Server (NTRS)

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

Pusch, Richard H.

1985-01-01

60

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

NASA Technical Reports Server (NTRS)

The research testing and demonstration of new bulk-fill materials for cryogenic thermal insulation systems was performed by the Cryogenics Test Laboratory at NASA Kennedy Space Center. Thermal conductivity testing under actual-use cryogenic conditions is a key to understanding the total system performance encompassing engineering, economics, and materials factors. A number of bulk fill insulation materials, including aerogel beads, glass bubbles, and perlite powder, were tested using a new cylindrical cryostat. Boundary temperatures for the liquid nitrogen boil-off method were 293 K and 78 K. Tests were performed as a function of cold vacuum pressure from high vacuum to no vacuum conditions. Results are compared with other complementary test methods in the range of 300 K to 20 K. Various testing techniques are shown to be required to obtain a complete understanding of 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.

2007-01-01

61

Development of tailorable advanced blanket insulation for advanced space transportation systems  

NASA Technical Reports Server (NTRS)

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

Calamito, Dominic P.

1987-01-01

62

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

63

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

64

Applications for silica aerogel products  

Microsoft Academic Search

Aerogels, nanoporous lightweight materials, were discovered more than 60 years ago. The supercritical manufacturing process and expensive raw materials typically used to produce aerogels prohibited commercialization on an industrial scale. Recently, a commercially attractive ambient pressure production process was developed which will allow broader commercialization of silica aerogel products. Some aerogel products for insulation applications and their preparation is described.

M. Schmidt; F Schwertfeger

1998-01-01

65

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

NASA Technical Reports Server (NTRS)

Since its launch in April 1990, the Hubble Space Telescope (HST) has made many important observations from its vantage point in low Earth orbit (LEO). However, as seen during five servicing missions, the outer layer of multilayer insulation (MLI) has become increasingly embrittled and has cracked in many areas. In May 2009, during the 5th servicing mission (called SM4), two MLI blankets were replaced with new insulation and the space-exposed MLI blankets were retrieved for degradation analyses by teams at NASA Glenn Research Center (GRC) and NASA Goddard Space Flight Center (GSFC). The retrieved MLI blankets were from Equipment Bay 8, which received direct sunlight, and Equipment Bay 5, which received grazing sunlight. Each blanket was divided into several regions based on environmental exposure and/or physical appearance. The aluminized-Teflon (DuPont, Wilmington, DE) fluorinated ethylene propylene (Al-FEP) outer layers of the retrieved MLI blankets have been analyzed for changes in optical, physical, and mechanical properties, along with chemical and morphological changes. Pristine and as-retrieved samples (materials) were heat treated to help understand degradation mechanisms. When compared to pristine material, the analyses have shown how the Al-FEP was severely affected by the space environment. Most notably, the Al-FEP was highly embrittled, fracturing like glass at strains of 1 to 8 percent. Across all measured properties, more significant degradation was observed for Bay 8 material as compared to Bay 5 material. This paper reviews the tensile and bend-test properties, density, thickness, solar absorptance, thermal emittance, x-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) elemental composition measurements, surface and crack morphologies, and atomic oxygen erosion yields of the Al-FEP outer layer of the retrieved HST blankets after 19 years of space exposure.

de Groh, Kim K.; Perry, Bruce A.; Mohammed, Jelila S.; Banks, Bruce

2015-01-01

66

Fabrication and performance of AIN insulator coatings for application in fusion reactor blankets  

SciTech Connect

The liquid-metal blanket concept for fusion reactors requires an coating on the first-wall structural material to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Based on the thermodynamics of interactions betwen the coating and the liquid lithium on one side and the structural V-base alloy on the other side, an AIN coating was selected as a candidate. Detailed investigations were conducted on the fabrication, metallurgical microstructure, compatibility in liquid Li, and electrical characteristics of AIN material obtained from several sources. Lithium compatibility was studied in static systems by exposing AIN-coated specimens to liquid Li for several time periods. Electrical resistance was measured at room temperature on the specimens before and after exposure to liquid Li. The results obtained in this study indicate that AIN is a viable coating from the standpoint of chemical compatibility in Li, electrical insulation, and ease of fabrication; for these reasons, the coating should be examined further for fusion reactor applications.

Natesan, K.

1995-09-01

67

Ambient Dried Aerogels  

NASA Technical Reports Server (NTRS)

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

Jones, Steven M.; Paik, Jong-Ah

2013-01-01

68

Technical applications of aerogels  

SciTech Connect

Aerogel materials posses such a wide variety of exceptional properties that a striking number of applications have developed for them. Many of the commercial applications of aerogels such as catalysts, thermal insulation, windows, and particle detectors are still under development and new application as have been publicized since the ISA4 Conference in 1994: e.g.; supercapacitors, insulation for heat storage in automobiles, electrodes for capacitive deionization, etc. More applications are evolving as the scientific and engineering community becomes familiar with the unusual and exceptional physical properties of aerogels, there are also scientific and technical application, as well. This paper discusses a variety of applications under development at Lawrence Livermore National Laboratory for which several types of aerogels are formed in custom sizes and shapes. Particular discussions will focus on the uses of aerogels for physics experiments which rely on the exceptional, sometimes unique, properties of aerogels.

Hrubesh, L.W.

1997-08-18

69

Compression molding of aerogel microspheres  

DOEpatents

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

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

1998-03-24

70

Compression molding of aerogel microspheres  

DOEpatents

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

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

1998-03-24

71

Thermal properties of organic and inorganic aerogels  

Microsoft Academic Search

Aerogels are open-cell foams that have already been shown to be among the best thermal insulating solid materials known. This paper examines the three major contributions to thermal transport through porous materials; solid, gaseous, and radiative, to identify how to reduce the thermal conductivity of air-filled aerogels. We find that significant improvements in the thermal insulation property of aerogels are

Lawrence W. Hrubesh; Richard W. Pekala

1994-01-01

72

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

SciTech Connect

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, S.L.; Jacobs, S.; Le, J.

1993-03-01

73

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

74

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

75

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

76

Mechanical Properties of Aerogels. Final Report  

Microsoft Academic Search

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

K. E. Parmenter; F. Milstein

1995-01-01

77

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

78

Improvements to the Synthesis of Polyimide Aerogels  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

79

Epoxy Crosslinked Silica Aerogels (X-Aerogels)  

NASA Technical Reports Server (NTRS)

NASA is interested in the development of strong lightweight materials for the dual role of thermal insulator and structural component for space vehicles; freeing more weight for useful payloads. Aerogels are very-low density materials (0.010 to 0.5 g/cc) that, due to high porosity (meso- and microporosity), can be, depending on the chemical nature of the network, ideal thermal insulators (thermal conductivity approx. 15 mW/mK). However, aerogels are extremely fragile. For practical application of aerogels, one must increase strength without compromising the physical properties attributed to low density. This has been achieved by templated growth of an epoxy polymer layer that crosslinks the "pearl necklace" network of nanoparticles: the framework of a typical silica aerogel. The requirement for conformal accumulation of the epoxy crosslinker is reaction both with the surface of silica and with itself. After cross-linking, the strength of a typical aerogel monolith increases by a factor of 200, in the expense of only a 2-fold increase in density. Strength is increased further by coupling residual unreacted epoxides with diamine.

fabrizio, Eve; Ilhan, Faysal; Meador, Mary Ann; Johnston, Chris; Leventis, Nicholas

2004-01-01

80

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

NASA Technical Reports Server (NTRS)

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

Leventis, Nicholas

2006-01-01

81

Gauge Measures Thicknesses Of Blankets  

NASA Technical Reports Server (NTRS)

Tool makes highly repeatable measurements of thickness of penetrable blanket insulation. Includes commercial holder for replaceable knife blades, which holds needle instead of knife. Needle penetrates blanket to establish reference plane. Ballasted slider applies fixed preload to blanket. Technician reads thickness value on scale.

Hagen, George R.; Yoshino, Stanley Y.

1991-01-01

82

Simplified Waterproofing of Aerogels  

NASA Technical Reports Server (NTRS)

A relatively simple silanization process has been developed for waterproofing or rewaterproofing aerogels, xerogels, and aerogel/tile composites, and other, similar low-density, highly microporous materials. Such materials are potentially attractive for a variety of applications especially for thermal-insulation panels that are required to be thin and lightweight. Unfortunately, such materials are also hydrophilic and tend to collapse after adsorbing water from the air. Hence, an effective means of waterproofing is necessary to enable practical exploitation of aerogels and the like. Older processes for waterproofing aerogels are time-consuming, labor-intensive, and expensive, relative to the present process. Each of the older processes includes a number of different chemical treatment steps, and some include the use of toxic halogenated surface-modifying compounds, pressures as high as hundreds of atmospheres, and/or temperatures as high as 1,000 C.

Hsu, Ming-Ta S.; Chen, Timothy S.; White, Susan; Rasky, Daniel J.

2003-01-01

83

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

84

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

85

Aerogel: Tile Composites Toughen a Brittle Superinsulation  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

86

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

87

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

88

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

89

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

90

Coated Aerogel Beads  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

91

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

92

CaO insulator and Be intermetallic coatings on V-base alloys for liquid-lithium fusion blanket applications  

Microsoft Academic Search

The objective of this study is to develop (a) stable CaO insulator coatings at the liquid-Li\\/structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the V-alloy wall, and (b) stable Be-V intermetallic coatings for first-wall components that face the plasma. Electrically insulating and corrosion-resistant coatings are required at the liquid-Li\\/structural interface in fusion

J.-H. Park; T. F. Kassner

1995-01-01

93

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

94

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

95

Method for producing metal oxide aerogels  

DOEpatents

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

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

1995-04-25

96

Method for producing metal oxide aerogels  

DOEpatents

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

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

1995-01-01

97

Aerogel Derived Nanostructured Thermoelectric Materials  

SciTech Connect

America’s dependence on foreign sources for fuel represents a economic and security threat for the country. These non renewable resources are depleting, and the effects of pollutants from fuels such as oil are reaching a problematic that affects the global community. Solar concentration power (SCP) production systems offer the opportunity to harness one of the United States’ most under utilized natural resources; sunlight. While commercialization of this technology is increasing, in order to become a significant source of electricity production in the United States the costs of deploying and operating SCP plants must be further reduced. Parabolic Trough SCP technologies are close to meeting energy production cost levels that would raise interest in the technology and help accelerate its adoption as a method to produce a significant portion of the Country’s electric power needs. During this program, Aspen Aerogels will develop a transparent aerogel insulation that can replace the costly vacuum insulation systems that are currently used in parabolic trough designs. During the Phase I program, Aspen Aerogels will optimize the optical and thermal properties of aerogel to meet the needs of this application. These properties will be tested, and the results will be used to model the performance of a parabolic trough HCE system which uses this novel material in place of vacuum. During the Phase II program, Aspen Aerogels will scale up this technology. Together with industry partners, Aspen Aerogels will build and test a prototype Heat Collection Element that is insulated with the novel transparent aerogel material. This new device will find use in parabolic trough SCP applications.

Wendell E Rhine, PI; Dong, Wenting; Greg Caggiano, PM

2010-10-08

98

Blanket technology experiments at Argonne National Laboratory  

SciTech Connect

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

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

1988-02-01

99

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

100

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

101

Synthesis and physico-chemical properties of organic aerogels  

NASA Astrophysics Data System (ADS)

Basically, an organic aerogel is any aerogel with a framework consists of organic polymers. The organic aerogels are fabricated by the sol-gel polymerization of resorcinol with formaldehyde, followed by exchanging with acetone, and then with liquid CO2 and drying under CO2 supercritical conditions. The organic aerogels obtained by this process exhibits themselves as an insulators i.e. they possesses high resistance to the flow of current through them. These obtained aerogels when heated at elevated temperatures of about 1100 °C they becomes conducting, demonstrates themselves a low resistance of the order of 4?.

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

2013-06-01

102

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

103

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

104

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

105

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

106

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.

1999-10-26

107

Polyimide Cellulose Nanocrystal Composite Aerogels  

NASA Technical Reports Server (NTRS)

Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

2014-01-01

108

Composite Silica Aerogels Opacified with Titania  

NASA Technical Reports Server (NTRS)

A further improvement has been made to reduce the high-temperature thermal conductivities of the aerogel-matrix composite materials described in Improved Silica Aerogel Composite Materials (NPO-44287), NASA Tech Briefs, Vol. 32, No. 9 (September 2008), page 50. Because the contribution of infrared radiation to heat transfer increases sharply with temperature, the effective high-temperature thermal conductivity of a thermal-insulation material can be reduced by opacifying the material to reduce the radiative contribution. Therefore, the essence of the present improvement is to add an opacifying constituent material (specifically, TiO2 powder) to the aerogel-matrix composites.

Paik, Jon-Ah; Sakamoto, Jeffrey; Jones, Steven; Fleurial, Jean-Pierre; DiStefano, Salvador; Nesmith, Bill

2009-01-01

109

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

110

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

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

111

Polyolefin-based aerogels  

NASA Technical Reports Server (NTRS)

The present invention relates to cross-linked polyolefin aerogels in simple and fiber-reinforced composite form. Of particular interest are polybutadiene aerogels. Especially aerogels derived from polybutadienes functionalized with anhydrides, amines, hydroxyls, thiols, epoxies, isocyanates or combinations thereof.

Lee, Je Kyun (Inventor); Gould, Gerogle L. (Inventor)

2010-01-01

112

Studying the Properties of Aerogel at MSFC  

NASA Technical Reports Server (NTRS)

Scientists at 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 to insulate the walls of houses and engine compartments in cars. It was also used in the space program as insulating material on the rover Sojourner, aboard the Mars Pathfinder. MSFC is one of the many research facilities conducting experiments to unlock the smoky properties of aerogel and make it a clear substance. MSFC researchers believe that by taking this research to space, they can resolve the problem of making aerogel transparent enough to see through. So far, recent space experiments have been encouraging. The samples produced in microgravity indicate a change in the microstructure of the material as compared to ground samples. MSFC scientists continue to study the effects of microgravity on Aerogel as their research is space continues.

1996-01-01

113

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

114

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

115

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

116

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

117

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

118

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

NASA Technical Reports Server (NTRS)

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

Leventis, Nicholas

2005-01-01

119

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

120

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

121

Compression of aerogels  

Microsoft Academic Search

When an aerogel is pressurized in a mercury porosimeter, the network is compressed, but no mercury enters the pores. Therefore, porosimetry cannot be used to measure the pore size distribution in an aerogel, but it does provide a measure of the bulk modulus of the network. For silica aerogels, the network is linearly elastic under small strains, then exhibits yield

George W. Scherer; Douglas M. Smith; Xiaomei Qiu; Julie M. Anderson

1995-01-01

122

Aerogel-lo  

NSDL National Science Digital Library

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

NASA

1999-01-01

123

Uncooled thin film pyroelectric IR detector with aerogel thermal isolation  

DOEpatents

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

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

1999-01-01

124

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

125

Improvements of reinforced silica aerogel nanocomposites thermal properties for architecture applications.  

PubMed

An 1,4-cis polybutadiene rubber/carboxymethyl starch (CMS)-based silica aerogel nanocomposites as a insulation material was developed that will provide superior thermal insulation properties, flexibility, toughness, durability of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. In this study, reinforced 1,4-cis polybutadiene-CMS-silica aerogel nanocomposites were prepared from a silica aerogel with a surface area 710 m(2) g(-1), a pore size of 25.3 nm and a pore volume of 4.7 cm(3) g(-1). The tensile properties and dynamic mechanical properties of 1,4-cis polybutadiene/CMS nanocomposites were systematically enhanced at low silica loading. Similar improvements in tensile modulus and strength have been observed for 1,4-cis polybutadiene/CMS mesoporous silica aerogel nanocomposites. PMID:25172161

Saboktakin, Amin; Saboktakin, Mohammad Reza

2015-01-01

126

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

127

Cellulose-silica aerogels.  

PubMed

Aerogels based on interpenetrated cellulose-silica networks were prepared and characterised. Wet coagulated cellulose was impregnated with silica phase, polyethoxydisiloxane, using two methods: (i) molecular diffusion and (ii) forced flow induced by pressure difference. The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude, for a sample with the same geometry. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix. Nitrogen adsorption analysis revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite. Morphology, thermal conductivity and mechanical properties under uniaxial compression were investigated. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of superinsulating mesoporous silica inside cellulose pores. Furthermore, composite aerogels were stiffer than each of reference aerogels. PMID:25817671

Demilecamps, Arnaud; Beauger, Christian; Hildenbrand, Claudia; Rigacci, Arnaud; Budtova, Tatiana

2015-05-20

128

Dielectric properties of aerogels  

Microsoft Academic Search

We have measured the real (dielectric constant) and imaginary (loss factor) components of the complex relative permittivity at 298 [degree]K using microwave frequencies (2, 10, and 18--40 GHz), for bulk SiO[sub 2]-aerogels and for two types of organic aerogels, resorcinol-formaldehyde (RF) and melamine-formaldehyde (MF). Measured dielectric constants are found to vary linearly between values of 1.0 and 2.0 for aerogel

L. W. Hrubesh; L. E. Keene; V. R. Latorre

1993-01-01

129

Method of casting aerogels  

DOEpatents

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

Poco, J.F.

1993-09-07

130

In Vivo Ultrasonic Detection of Polyurea Crosslinked Silica Aerogel Implants  

PubMed Central

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

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

2013-01-01

131

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

132

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

133

Superhydrophobic functionalized graphene aerogels.  

PubMed

Carbon-based nanomaterials such as carbon nanotubes and graphene are excellent candidates for superhydrophobic surfaces because of their intrinsically high surface area and nonpolar carbon structure. This paper demonstrates that graphene aerogels with a silane surface modification can provide superhydrophobicity. Graphene aerogels of various concentrations were synthesized and the receding contact angle of a water droplet was measured. It is shown that graphene aerogels are hydrophobic and become superhydrophobic following the application of a fluorinated surfactant. The aerogels produced for this experiment outperform previous carbon nanomaterials in creating superhydrophobic surfaces and offer a more scalable synthetic procedure for production. PMID:21714511

Lin, Yirong; Ehlert, Gregory J; Bukowsky, Colton; Sodano, Henry A

2011-07-01

134

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

135

Mechanically Strong, Lightweight Porous Materials Developed (X-Aerogels)  

NASA Technical Reports Server (NTRS)

Aerogels are attractive materials for a variety of NASA missions because they are ultralightweight, have low thermal conductivity and low-dielectric constants, and can be readily doped with other materials. Potential NASA applications for these materials include lightweight insulation for spacecraft, habitats, and extravehicular activity (EVA) suits; catalyst supports for fuel cell and in situ resource utilization; and sensors for air- and water-quality monitoring for vehicles, habitats, and EVA suits. Conventional aerogels are extremely fragile and require processing via supercritical fluid extraction, which adds cost to the production of an aerogel and limits the sizes and geometries of samples that can be produced from these materials. These issues have severely hampered the application of aerogels in NASA missions.

Leventis, Nicholas

2005-01-01

136

Carbon Nanofiber Incorporated Silica Based Aerogels with Di-Isocyanate Cross-Linking  

NASA Technical Reports Server (NTRS)

Lightweight materials with excellent thermal insulating properties are highly sought after for a variety of aerospace and aeronautic applications. (1) Silica based aerogels with their high surface area and low relative densities are ideal for applications in extreme environments such as insulators for the Mars Rover battery. (2) However, the fragile nature of aerogel monoliths prevents their widespread use in more down to earth applications. We have shown that the fragile aerogel network can be cross-linked with a di-isocyanate via amine decorated surfaces to form a conformal coating. (3) This coating reinforces the neck regions between secondary silica particles and significantly strengthens the aerogels with only a small effect on density or porosity. Scheme 1 depicts the cross-linking reaction with the di-isocyanate and exhibits the stages that result in polymer cross-linked aerogel monoliths.

Vivod, Stephanie L.; Meador, Mary Ann B.; Capadona, Lynn A.; Sullivan, Roy M.; Ghosn, Louis J.; Clark, Nicholas; McCorkle, Linda

2008-01-01

137

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

138

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.

139

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

140

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

141

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

142

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

143

Nanoengineering Strong Silica Aerogels  

Microsoft Academic Search

ABSTRACT In the quest for strong lightweight materials, silica aerogels would be very attractive, if they were not fragile. The strength of silica aerogel monoliths has been improved by a factor of over 100 through cross-linking the nanoparticle building blocks of preformed silica hydrogels with poly(hexamethylene diisocyanate). Composite monoliths are much less hygroscopic than native silica, and they do not

Nicholas Leventis; Chariklia Sotiriou-Leventis; Guohui Zhang; Abdel-Monem M. Rawashdeh

2002-01-01

144

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

145

Melamine-formaldehyde aerogels  

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1992-01-01

146

Carbon aerogels for electrochemical applications  

Microsoft Academic Search

A major advantage of highly crosslinked, organic aerogels is the ability to transform many of these materials into electrically conductive carbon aerogels. Carbon aerogels have been formed as monoliths, microspheres, irregularly-shaped powders, and thin film composites. In all cases, the carbon aerogels retain their high surface area (400–800 m2\\/g) and ultrafine cell\\/pore size (<100 nm). Carbon aerogels are being examined

R. W. Pekala; J. C. Farmer; C. T. Alviso; T. D. Tran; S. T. Mayer; J. M. Miller; B. Dunn

1998-01-01

147

Method for producing hydrophobic aerogels  

DOEpatents

A method for treating a dried monolithic aerogel containing non-dispersed particles, with an organometallic surface modifying agent to produce hydrophobic aerogels. The dried, porous hydrophobic aerogels contain a protective layer of alkyl groups, such as methyl groups, on the modified surfaces of the pores of the aerogel. The alkyl groups at the aerogel surface typically contain at least one carbon-metal bond per group.

Hrubesh, Lawrence W. (Pleasanton, CA); Poco, John F. (Livermore, CA); Coronado, Paul R. (Livermore, CA)

1999-01-01

148

Silica aerogel-polymer nanocomposites and new nanoparticle syntheses  

NASA Astrophysics Data System (ADS)

Aerogels are extremely high surface area, low density materials with applications including thermal and acoustic insulators, radiation detectors and cometary dust particle traps. However, their low density and aggregate structure makes them extremely fragile and practically impossible to machine or handle without breaking. This has led to the development of aerogel composites with enhanced mechanical properties through the addition of polymers or surface modifiers. To date, attempts to strengthen aerogels have come with significant increases in density and processing time. Here I will describe our search for a solution to these problems with our invention using methyl cyanoacrylate chemical vapor deposition (CVD) to strengthen silica, aminated silica and bridged polysilsesquioxane aerogels. This approach led to a strength improvement of the composites within hours and the strongest composite prepared had a 100x strength improvement over the precursor aerogel. We also developed the first approach to control the molecular weight of the polymers that reinforce silica aerogels using surface-initiated atom transfer radical polymerization (SI-ATRP). Although PMMA reinforcement of silica aerogels improved the mechanical properties, further strength improvements were achieved by cross-linking the grafted PMMA. Additionally, we developed the first silica aerogels reinforced with polyaniline nanofibers that were strong and electrically conductive. Reinforcing silica aerogels with polyaniline allowed them to be used as a sensor for the detection of protonating and deprotonating gaseous species. Finally we developed a new approach for the synthesis of silica and bridged polysilsesquioxane spheres using a surfactant free synthesis. This approach allowed for the first in-situ incorporation of base sensitive functionalities during the sol-gel polymerization.

Boday, Dylan Joseph

149

Polyimide Aerogels with Three-Dimensional Cross-Linked Structure  

NASA Technical Reports Server (NTRS)

Polyimide aerogels with three-dimensional cross-linked structure are made using linear oligomeric segments of polyimide, and linked with one of the following into a 3D structure: trifunctional aliphatic or aromatic amines, latent reactive end caps such as nadic anhydride or phenylethynylphenyl amine, and silica or silsesquioxane cage structures decorated with amine. Drying the gels supercritically maintains the solid structure of the gel, creating a polyimide aerogel with improved mechanical properties over linear polyimide aerogels. Lightweight, low-density structures are desired for acoustic and thermal insulation for aerospace structures, habitats, astronaut equipment, and aeronautic applications. Aerogels are a unique material for providing such properties because of their extremely low density and small pore sizes. However, plain silica aerogels are brittle. Reinforcing the aerogel structure with a polymer (X-Aerogel) provides vast improvements in strength while maintaining low density and pore structure. However, degradation of polymers used in cross-linking tends to limit use temperatures to below 150 C. Organic aerogels made from linear polyimide have been demonstrated, but gels shrink substantially during supercritical fluid extraction and may have lower use temperature due to lower glass transition temperatures. The purpose of this innovation is to raise the glass transition temperature of all organic polyimide aerogel by use of tri-, tetra-, or poly-functional units in the structure to create a 3D covalently bonded network. Such cross-linked polyimides typically have higher glass transition temperatures in excess of 300 400 C. In addition, the reinforcement provided by a 3D network should improve mechanical stability, and prevent shrinkage on supercritical fluid extraction. The use of tri-functional aromatic or aliphatic amine groups in the polyimide backbone will provide such a 3D structure.

Panek, John

2010-01-01

150

Traditional, state-of-the-art and future thermal building insulation materials and solutions – Properties, requirements and possibilities  

Microsoft Academic Search

The advantages and disadvantages of the thermal building insulation materials and solutions have been treated. Both traditional, state-of-the-art and possible materials and solutions beyond these have been investigated. Examples of these may be mineral wool, expanded polystyrene, extruded polystyrene, polyurethane, vacuum insulation panels, gas insulation panels, aerogels, and future possibilities like vacuum insulation materials, nano insulation materials and dynamic insulation

Bjørn Petter Jelle

2011-01-01

151

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

E-print Network

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

Abdou, Mohamed

152

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

153

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

1996-04-16

154

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

155

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

NASA Astrophysics Data System (ADS)

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 silica aerogels, which are fragile. Amongst polymeric aerogels, those based on polybenzoxazine (PBO - a type of phenolic resin), are extremely robust and comprise an economic alternative to resorcinol-formaldehyde aerogels, also a class of phenolic resins, as the main source of carbon aerogels. The drawback of the PBO chemistry has been the long (days) processing time at high-temperatures (>130 °C). Herewith, we have developed an energy- and time-efficient process to PBO aerogels by inducing acid-catalyzed gelation at room-temperature completed in a few hours. The new aerogels are compared directly with their conventional counterparts and are found equivalent or better in terms of mechanical strength, thermal insulation value, surface area and carbonization yield. Hexahydrated iron chloride (FeCl3.6H2O) is a fairly strong Bronsted acid, which, based on the above, catalyzes formation interpenetrating networks of PBO and iron oxide nanoparticles (PBO-FeOx). Pyrolysis of that intimate mixture of a carbon source (PBO) and iron oxide undergoes smelting to highly porous (>90% v/v) monolithic metallic iron aerogels. The porous network was loaded with oxidizers (e.g., LiClO4) into a new class of energetic materials (thermites, explosives, pyrotechnics). The PBO aerogels developed here comprise a wide-base platform for use as thermal insulators in civil and transportation applications (PBO aerogels themselves), electrodes for fuel cells, lithium ion batteries (nanoporous carbons), catalysts and energetic materials (PBO-FeOx).

Mahadik-Khanolkar, Shruti

156

Comparative study of aerogels obtained from differently prepared nanocellulose fibers.  

PubMed

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

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

2014-01-01

157

Hydrophobic silica aerogels  

Microsoft Academic Search

Hydrophobic silica aerogels were produced by the -Si(Me)3 (trimethylsilyl substituent: TMS) modification of alcogels followed by CO2 supercritical drying. The structure of trimethylsilyl modified silica aerogel (TMSA) was the silica matrix produced by hydrolysis and condensation of only tetramethoxysilane (TMOS). TMS was modified on the surface of the silica matrix. TMSA was extremely moisture-resistant. The density, size, and transparency of

H. Yokogawa; M. Yokoyama

1995-01-01

158

Method of casting aerogels  

DOEpatents

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

Poco, John F. (Livermore, CA)

1993-01-01

159

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

160

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

161

High power density self-cooled lithium-vanadium blanket.  

SciTech Connect

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

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

1999-07-01

162

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

163

Performance of uncoated AFRSI blankets during multiple Space Shuttle flights  

Microsoft Academic Search

Uncoated Advanced Flexible Reusable Surface Insulation (AFRSI) blankets were successfully flown on seven consecutive flights of the Space Shuttle Orbiter OV-099 (Challenger). In six of the eight locations monitored (forward windshield, forward canopy, mid-fuselage, upper wing, rudder\\/speed brake, and vertical tail) the AFRSI blankets performed well during the ascent and reentry exposure to the thermal and aeroacoustic environments. Several of

Paul M. Sawko; Howard E. Goldstein

1992-01-01

164

Evaluation of Aerogel Materials for High-Temperature Batteries  

SciTech Connect

Siiica aerogels have 1/3 the thermal conductivity of the best commercial composite insulations, or ~13 mW/m-K at 25°C. However, aerogels are transparent in the near IR region of 4-7 µm, which is where the radiation peak from a thermal-battery stack occurs. Titania and carbon- black powders were examined as thermal opacifiers, to reduce radiation at temperatures between 300°C and 600°C, which spans the range of operating temperature for most thermal batteries. The effectiveness of the various opacifiers depended on the loading, with the best overall results being obtained using aerogels filled with carbon black. Fabrication and strength issues still remain, however.

Ashley, Carol S.; Guidotti, Ronald A.; Reed, Scott T.; Reinhardt, Frederick W.

1999-05-04

165

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

PubMed

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

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

2013-07-10

166

Method of low pressure and/or evaporative drying of aerogel  

DOEpatents

A process is described whereby Resorcinol/Formaldehyde (RF) aerogel having a density of about 0.4--1.2 g/cc can be manufactured using a simple air drying procedure. This process is inherently simpler, quicker, and less expensive than the more conventional supercritical or subcritical CO{sub 2} extraction procedures. RF aerogels can be used as produced, such as in insulation applications, or pyrolyzed to form carbon aerogels with a density of about 0.9 g/cc for use in applications such as batteries, supercapacitors, etc.

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

1995-05-30

167

Method of low pressure and/or evaporative drying of aerogel  

DOEpatents

A process whereby Resorcinol/Formaldehyde (RF) aerogel having a density of about 0.4-1.2 g/cc can be manufactured using a simple air drying procedure. This process is inherently simpler, quicker, and less expensive than the more conventional supercritical or subcritical CO.sub.2 extraction procedures. RF aerogels can be used as produced, such as in insulation applications, or pyrolyzed to form carbon aerogels with a density of about 0.9 g/cc for use in applications such as batteries, supercapacitors, etc.

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

1995-01-01

168

Aerogel for FARICH detector  

NASA Astrophysics Data System (ADS)

We present our current experience in preparation of focusing aerogels for the Focusing Aerogel RICH detector. Multilayer focusing aerogel tiles have been produced in Novosibirsk by a collaboration of the Budker Institute of Nuclear Physics and Boreskov Institute of Catalysis since 2004. We have obtained 2-3-4-layer blocks with the thickness of 30-45 mm. In 2012, the first samples of focusing blocks with continuous density (refractive index) gradient along thickness were produced. This technology can significantly reduce the contribution from the geometric factor of the radiator thickness to the resolution of the measured Cherenkov angle in the FARICH detector. The special installation was used for automatic control of reagents ratio during the synthesis process. The first samples were tested using the digital radiography method and on the electron beam with the FARICH prototype.

Barnyakov, A. Yu.; Barnyakov, M. Yu.; Bobrovnikov, V. S.; Buzykaev, A. R.; Gulevich, V. V.; Danilyuk, A. F.; Kononov, S. A.; Kravchenko, E. A.; Kuyanov, I. A.; Lopatin, S. A.; Onuchin, A. P.; Ovtin, I. V.; Podgornov, N. A.; Porosev, V. V.; Predein, A. Yu.; Protsenko, R. S.

2014-12-01

169

21 CFR 182.1711 - Silica aerogel.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false 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...

2013-04-01

170

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

171

21 CFR 582.1711 - Silica aerogel.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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...

2012-04-01

172

21 CFR 182.1711 - Silica aerogel.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false 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...

2014-04-01

173

21 CFR 582.1711 - Silica aerogel.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

174

21 CFR 582.1711 - Silica aerogel.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 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...

2011-04-01

175

21 CFR 182.1711 - Silica aerogel.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false 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...

2012-04-01

176

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

177

21 CFR 182.1711 - Silica aerogel.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false 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...

2011-04-01

178

21 CFR 582.1711 - Silica aerogel.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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...

2014-04-01

179

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

180

Nanofibrillar cellulose aerogels  

Microsoft Academic Search

Highly porous aerogels consisting of cellulose nanofibrils were prepared by dissolution\\/regeneration of cellulose in aq. calcium thiocyanate followed by regeneration and carefully controlled drying. The influence of drying method (regular freeze drying, rapid freeze drying, and solvent exchange drying) on resulting porosity was studied by electron microscopy and nitrogen adsorption. While regular freeze drying caused significant coalescence of microfibrillar units,

Hao Jin; Yoshiharu Nishiyama; Masahisa Wada; Shigenori Kuga

2004-01-01

181

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

E-print Network

lithium flow rate implies MHD insulator coating is not required at the first wall and blanket #12 to address: G Fundamental liquid lithium experiments G W-alloy fabrication, testing and experiments #12 Transpiration FW and Blanket Parameters G FW surface heat flux, MW/m2 2 G Toroidal magnetic field strength

California at Los Angeles, University of

182

X-Aerogels for Structural Components and High Temperature Applications  

NASA Technical Reports Server (NTRS)

Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process took a couple of days. It was experimentally determined that the polymerization reaction could be done in acetonitrile instead of THF with no detrimental effects to the properties of the resulting aerogel. Other changes in the time needed to crosslink the gels in the isocyanate solution as well as changes to the subsequent washing procedure could also shorten the processing time with no effect on the properties. Processing methods were also developed that allowed a variety of shapes as well as sizes of these materials to be formed.

2005-01-01

183

Cellulose-based aerogels  

Microsoft Academic Search

New organic aerogels were prepared using cellulose derivatives as precursors. The elaboration process and the structural characterisations of these porous cellulose-based materials are described in the present study. Series of monolithic gels were synthesised in acetone by crosslinking cellulose acetate with a non-toxic isocyanate via sol–gel route, using tin-based catalyst. Gelation times (ranging from 15 to 150min) were significantly dependent

F. Fischer; A. Rigacci; R. Pirard; S. Berthon-Fabry; P. Achard

2006-01-01

184

Performance of uncoated AFRSI blankets during multiple Space Shuttle flights  

NASA Astrophysics Data System (ADS)

Uncoated Advanced Flexible Reusable Surface Insulation (AFRSI) blankets were successfully flown on seven consecutive flights of the Space Shuttle Orbiter OV-099 (Challenger). In six of the eight locations monitored (forward windshield, forward canopy, mid-fuselage, upper wing, rudder/speed brake, and vertical tail) the AFRSI blankets performed well during the ascent and reentry exposure to the thermal and aeroacoustic environments. Several of the uncoated AFRSI blankets that sustained minor damage, such as fraying or broken threads, could be repaired by sewing or by patching with a surface coating called C-9. The chief reasons for replacing or completely coating a blanket were fabric embrittlement and fabric abrasion caused by wind erosion. This occurred in the orbiter maneuvering system (OMS) pod sidewall and the forward mid-fuselage locations.

Sawko, Paul M.; Goldstein, Howard E.

1992-04-01

185

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

186

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

187

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

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1996-01-01

188

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

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1995-01-01

189

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

190

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

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1998-04-28

191

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

DOEpatents

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

Pekala, R.W.

1996-09-17

192

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

DOEpatents

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

Pekala, R.W.

1998-04-28

193

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

DOEpatents

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

Pekala, R.W.

1995-12-19

194

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

SciTech Connect

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

Not Available

1995-01-01

195

Button cell supercapacitors with monolithic carbon aerogels  

Microsoft Academic Search

Carbon aerogels are highly porous materials prepared via pyrolysis of resorcinol–formaldehyde aerogels. The density of the aerogels can be varied in a wide range, whereby the major part of the pores is accessible to ionic conductors. Therefore, the application of high surface area aerogels as electrodes in supercapacitor devices is promising. In the present publication, the integration of thin monolithic

H. Pröbstle; C. Schmitt; J. Fricke

2002-01-01

196

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

197

Superfluid 3He in Aerogel  

Microsoft Academic Search

We report measurements of the superfluid density and transition temperature of 3He confined within 98.2% open aerogel. Both the superfluid fraction and the temperature at which the superfluid is manifested are suppressed strongly from their bulk values. The results suggest that the aerogel reduces the order parameter by a mechanism other than as a diffusely scattering surface.

J. V. Porto; J. M. Parpia

1995-01-01

198

Aerogels: production, characterization, and applications  

Microsoft Academic Search

Aerogels are unique materials with many fascinating properties. A scientific curiosity since being prepared in the 1930's, today's research has focused on potential applications and more economic production routes. In this paper, we present a historic review of aerogels while bringing the reader up-to-date on the latest technological developments.

J. Fricke; T Tillotson

1997-01-01

199

Cosmic Dust Collection in Aerogel  

Microsoft Academic Search

Aerogel is an ultra-low-density material that can be used to capture small particles incident upon it at speeds in excess of 1 km s1. This permits capture of cosmic dust in space where the high speeds usually result in destructive impact events. The performance of aerogel in laboratory impact tests is described. Completely intact capture is rare; most studies show

Mark J. Burchell; Giles Graham; Anton Kearsley

2006-01-01

200

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

201

Perioperative thermal insulation.  

PubMed

To determine the efficacy of passive insulators advocated for prevention of cutaneous heat loss, we determined heat loss in unanesthetized volunteers covered by one of the following: a cloth "split sheet" surgical drape; a Convertors disposable-paper split sheet; a Thermadrape disposable laparotomy sheet; an unheated Bair Hugger patient-warming blanket; 1.5-mil-thick plastic hamper bags; and a prewarmed, cotton hospital blanket. Cutaneous heat loss was measured using 10 area-weighted thermal flux transducers while volunteers were exposed to a 20.6 degrees C environment for 1 h. Heat loss decreased significantly from 100 +/- 3 W during the control periods to 69 +/- 6 W (average of all covers) after 1 h of treatment. Heat losses from volunteers insulated by the Thermadrape (61 +/- 6 W) and Bair Hugger covers (64 +/- 5 W) were significantly less than losses from those insulated by plastic bags (77 +/- 11 W). The paper drape (67 +/- 7 W) provided slightly, but not significantly, better insulation than the cloth drape (70 +/- 4 W). Coverage by prewarmed cotton blankets initially resulted in the least heat loss (58 +/- 8 W), but after 40 min, resulted in heat loss significantly greater than that for the Thermadrape (71 +/- 7 W). Regional heat loss was roughly proportional to surface area, and the distribution of regional heat loss remained similar with all covers. These data suggest that cost and convenience should be major factors when choosing among passive perioperative insulating covers. It is likely that the amount of skin surface covered is more important than the choice of skin region covered or the choice of insulating material. PMID:2021204

Sessler, D I; McGuire, J; Sessler, A M

1991-05-01

202

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

203

Nanoencapsulated aerogels produced by monomer vapor deposition and polymerization  

NASA Technical Reports Server (NTRS)

Polymer coated aerogel comprising aerogel substrate comprising a substantially uniform polymer coating. In an embodiment, the polymer coated aerogel is comprised of a porosity and has a compressive modulus greater than the compressive modulus of the aerogel substrate.

Sullivan, Thomas A. (Inventor)

2011-01-01

204

Thermal Insulation Strips Conserve Energy  

NASA Technical Reports Server (NTRS)

Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be hydrophobic, and can withstand extremely hot temperatures (from 1,100 F to 3,000 F depending on the type of aerogel) down to cryogenic levels, making this "frozen smoke" ideal for use in space. Because of its low weight and ability to withstand temperature extremes, an aerogel was even used as the space-based catcher s mitt to trap comet particles and space dust for NASA s Stardust mission, launched in 1999. All of this remarkable technology s characteristics were ideal for NASA s purposes except one: The aerogels were extremely brittle. Through a long-term partnership between Kennedy Space Center and Aspen Aerogels Inc., of Northborough, Massachusetts, researchers developed a flexible, durable form of aerogel that NASA has since used as cryogenic insulation for space shuttle launch systems. Through Aspen Aerogels, the technology has made oil pipeline insulation, extreme weather clothing, and infrared shielding for combat helicopters.

2009-01-01

205

ITER breeding blanket design  

SciTech Connect

A breeding blanket design has been developed for ITER to provide the necessary tritium fuel to achieve the technical objectives of the Enhanced Performance Phase. It uses a ceramic breeder and water coolant for compatibility with the ITER machine design of the Basic Performance Phase. Lithium zirconate and lithium oxide am the selected ceramic breeders based on the current data base. Enriched lithium and beryllium neutron multiplier are used for both breeders. Both forms of beryllium material, blocks and pebbles are used at different blanket locations based on thermo-mechanical considerations and beryllium thickness requirements. Type 316LN austenitic steel is used as structural material similar to the shielding blanket. Design issues and required R&D data are identified during the development of the design.

Gohar, Y.; Cardella, A.; Ioki, K.; Lousteau, D.; Mohri, K.; Raffray, R.; Zolti, E. [ITER Joint Central Team, Garching (Germany)] [and others

1995-12-31

206

Ultralight nanofibre-assembled cellular aerogels with superelasticity and multifunctionality.  

PubMed

Three-dimensional nanofibrous aerogels (NFAs) that are both highly compressible and resilient would have broad technological implications for areas ranging from electrical devices and bioengineering to damping materials; however, creating such NFAs has proven extremely challenging. Here we report a novel strategy to create fibrous, isotropically bonded elastic reconstructed (FIBER) NFAs with a hierarchical cellular structure and superelasticity by combining electrospun nanofibres and the fibrous freeze-shaping technique. Our approach causes the intrinsically lamellar deposited electrospun nanofibres to assemble into elastic bulk aerogels with tunable densities and desirable shapes on a large scale. The resulting FIBER NFAs exhibit densities of >0.12 mg cm(-3), rapid recovery from deformation, efficient energy absorption and multifunctionality in terms of the combination of thermal insulation, sound absorption, emulsion separation and elasticity-responsive electric conduction. The successful synthesis of such fascinating materials may provide new insights into the design and development of multifunctional NFAs for various applications. PMID:25512095

Si, Yang; Yu, Jianyong; Tang, Xiaomin; Ge, Jianlong; Ding, Bin

2014-01-01

207

Ultralight nanofibre-assembled cellular aerogels with superelasticity and multifunctionality  

NASA Astrophysics Data System (ADS)

Three-dimensional nanofibrous aerogels (NFAs) that are both highly compressible and resilient would have broad technological implications for areas ranging from electrical devices and bioengineering to damping materials; however, creating such NFAs has proven extremely challenging. Here we report a novel strategy to create fibrous, isotropically bonded elastic reconstructed (FIBER) NFAs with a hierarchical cellular structure and superelasticity by combining electrospun nanofibres and the fibrous freeze-shaping technique. Our approach causes the intrinsically lamellar deposited electrospun nanofibres to assemble into elastic bulk aerogels with tunable densities and desirable shapes on a large scale. The resulting FIBER NFAs exhibit densities of >0.12?mg?cm?3, rapid recovery from deformation, efficient energy absorption and multifunctionality in terms of the combination of thermal insulation, sound absorption, emulsion separation and elasticity-responsive electric conduction. The successful synthesis of such fascinating materials may provide new insights into the design and development of multifunctional NFAs for various applications.

Si, Yang; Yu, Jianyong; Tang, Xiaomin; Ge, Jianlong; Ding, Bin

2014-12-01

208

Development of LiPb–SiC High Temperature Blanket  

Microsoft Academic Search

\\u000a This paper reports the development LiPb–SiC blanket concept aimed at the high performance liquid blanket to be feasible in\\u000a the near future.\\u000a \\u000a \\u000a It is based on the current LiPb liquid tritium breeder concept with reduced activation ferritic\\/martensitic steel (RAFM),\\u000a but with cooling panels made of SiC\\/SiC material that thermally and electrically insulate RAFM from LiPb. Extraction of thermal\\u000a energy over

Dohyoung Kim; Kazuyuki Noborio; Takayasu Hasegawa; Yasushi Yamamoto; Satoshi Konishi

209

Super-hydrophobic fluorine containing aerogels  

DOEpatents

An aerogel material with surfaces containing fluorine atoms which exhibits exceptional hydrophobicity, or the ability to repel liquid water. Hydrophobic aerogels are efficient absorbers of solvents from water. Solvents miscible with water are separated from it because the solvents are more volatile than water and they enter the porous aerogel as a vapor across the liquid water/solid interface. Solvents that are immisicble with water are separated from it by selectively wetting the aerogel. The hydrophobic property is achieved by formulating the aerogel using fluorine containing molecules either directly by addition in the sol-gel process, or by treating a standard dried aerogel using the vapor of fluorine containing molecules.

Coronado, Paul R. (Livermore, CA); Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

2007-05-01

210

Monolayer coated aerogels and method of making  

DOEpatents

Aerogels having a monolayer coating are described. The aerogel and a monolayer forming precursor are provided in a supercritical fluid, whereupon the aerogel and the monolayer forming precursor are reacted in said supercritical fluid to form a covalent bond between the aerogel and the monolayer forming precursor. Suitable aerogels are ceramic oxides such as silica, alumina, aluminosilicate, and combinations thereof. Suitable monolayer forming precursors include alkyl silanes, chlorosilanes, boranes, chloroboranes, germanes, and combinations thereof. The method may also include providing a surface preparation agent such as water, or hydroetching an aerogel to enhance the coating of the monolayer.

Zemanian, Thomas Samuel (Richland, WA); Fryxell, Glen (Kennwick, WA); Ustyugov, Oleksiy A. (Spokane, WA)

2006-03-28

211

Dynamics of capillary condensation in aerogels  

SciTech Connect

Dynamics of capillary condensation of liquid {sup 4}He in various density silica aerogels was investigated systematically. Interfaces were clearly visible when bulk liquid was rapidly sucked into the aerogel. Time evolution of the interface positions was consistent with the Washburn model and their effective pore radii were obtained. Condensation was a single step in a dense aerogel and two steps in a low density aerogel. Crossover between the two types of condensation was observed in an intermediate density aerogel. Variety of the dynamics may be the manifestation of the fractal nature of aerogels which had a wide range of distribution of pore radii.

Nomura, R.; Miyashita, W.; Yoneyama, K.; Okuda, Y. [Department of Condensed Matter Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8551 (Japan)

2006-03-15

212

Impact Crater ejecta blanket  

E-print Network

rim Impact Crater Morphology rim cavity ejecta blanket (ejecta) #12;Craters on Earth #12;Wolf Creek, Australia Meteor Crater, Arizona #12;Venus as a Planet Diameter = 12,104 km Density = 5 2 g/cm3Density = 5 ~ 1000 impact cratersvolcanoes, dune fields, rift valleys, ~ 1000 impact craters. No Plate Tectonics

Jurdy, Donna M.

213

High Temperature Aerogels in the Al2O3-SiO2 System  

NASA Technical Reports Server (NTRS)

Al2O3-SiO2 aerogels are of interest as constituents of thermal insulation systems for use at high temperatures. Al2O3 and mullite aerogels are expected to crystallize at higher temperatures than their SiO2 counterparts, hence avoiding the shrinkages that accompany the formation of lower temperature SiO2 phases and preserving pore structures into higher temperature regimes. The objective of this work is to determine the influence of processing parameters on shrinkage, gel structure (including surface area, pore size and distribution) and pyrolysis behavior.

Hurwitz, Frances I.; Aranda, Denisse V.; Gallagher, Meghan E.

2008-01-01

214

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

215

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

216

Slotted Polyimide-Aerogel-Filled-Waveguide Arrays  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

217

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

218

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

219

Multipurpose hardened spacecraft insulation  

NASA Technical Reports Server (NTRS)

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

Steimer, Carlos H.

1990-01-01

220

Design and Development of Aerogel-Based Antennas for Aerospace Applications: A Final Report to the NARI Seedling  

NASA Technical Reports Server (NTRS)

As highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties, polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aircraft antenna systems. While they have been aggressively explored for thermal insulation, barely any effort has been made to leverage these materials for antennas or other applications that take advantage of their aforementioned attributes. In Phase I of the NARI Seedling Project, we fabricated PI aerogels with properties tailored to enable new antenna concepts with performance characteristics (wide bandwidth and high gain) and material properties (low density, environmental stability, and robustness) superior to the state of practice (SOP). We characterized electromagnetic properties, including permittivity, reflectivity, and propagation losses for the aerogels. Simple, prototype planar printed circuit patch antennas from down-selected aerogel formulations were fabricated by molding the aerogels to net shapes and by gold-metalizing the pattern onto the templates via electron beam evaporation in a clean room environment. These aerogel based antennas were benchmarked against current antenna SOP, and exhibited both broader bandwidth and comparable or higher gain performance at appreciably lower mass. Phase II focused on the success of the Phase I results pushing the PI aerogel based antenna technology further by exploring alternative antenna design (i.e., slot coupled antennas) and by examining other techniques for fabricating the antennas including ink jet printing with the goal of optimizing antenna performance and simplifying production. We also examined new aerogel formulations with better moisture and solvent resistance to survive processing conditions. In addition, we investigated more complex antenna designs including passive phased arrays such as 2x4 and 4x8 element arrays to assess the scalability of the aerogel antenna concept. Furthermore, we explored the possibility of developing these arrays in thin, flexible form to make conformable antennas.

Meador, Mary Ann B.; Miranda, Felix A.

2014-01-01

221

High surface area silicon carbide-coated carbon aerogel  

DOEpatents

A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust. Carbon aerogels can be coated with sol-gel silica and the silica can be converted to silicone carbide, improved the thermal stability of the carbon aerogel.

Worsley, Marcus A; Kuntz, Joshua D; Baumann, Theodore F; Satcher, Jr, Joe H

2014-01-14

222

Biodegradable Pectin/clay Aerogels  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

223

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

224

High surface area carbon aerogels for supercapacitors  

Microsoft Academic Search

Applications of carbon aerogels as electrodes in supercapacitors require high surface area and simple production method. Carbon aerogels are derived via the pyrolysis of resorcinol-formaldehyde (RF) aerogels. In order to simplify production, subcritical drying of the RF gels is favoured, which is possible for gels prepared with high molar resorcinol to catalyst (R\\/C) ratios, i.e. very low catalyst concentrations. Resulting

R. Saliger; U Fischer; C Herta; J Fricke

1998-01-01

225

Hypervelocity impact experiments on aerogel dust collector  

Microsoft Academic Search

Laboratory hypervelocity impact experiments were conducted to verify the performance of aerogel dust collectors used for gathering meteoroids and space debris in the near-Earth environment and to derive the relationships of various parameters characterizing the projectile with morphology of tracks left by the penetrating projectile in the aerogel collector pad. Silica aerogel collectors of 0.03 g\\/cm3 density were impacted at

Yukihito Kitazawa; Akira Fujiwara; Toshihiko Kadono; Kichiro Imagawa; Yutaka Okada; Kazuo Uematsu

1999-01-01

226

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

227

Thermomechanical analysis of the ITER breeding blanket  

Microsoft Academic Search

Thermomechanical performance of the ITER breeding blanket is an important design issue because it requires first, that the thermal expansion mismatch between the blanket structure and the blankets internals (such as, beryllium multiplier and tritium breeders) can be accommodated without creating high stresses, and second, that the thermomechanical deformation of various interfaces within the blanket does not create high resistance

S. Majumdar; H. Gruhn; Y. Gohar; M. Giegerich

1997-01-01

228

Fusion reactor blanket\\/shield design study  

Microsoft Academic Search

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

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

1979-01-01

229

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

230

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

231

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

232

Space environment durability of beta cloth in LDEF thermal blankets  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

233

Nano-casted Metal Oxide Aerogels as Dual Purpose Structural Components for Space Exploration  

NASA Technical Reports Server (NTRS)

NASA missions and space exploration rely on strong, ultra lightweight materials. Such materials are needed for building up past and present space vehicles such as the Sojourner Rover (1997) or the two MERs (2003), but also for a number of components and/or systems including thermal insulators, Solar Sails, Rigid Aeroshells, and Ballutes. The purpose of my internship here at Glenn Research Center is to make dual purpose materials; materials that in addition to being lightweight have electronic, photophysical and magnetic properties and, therefore, act as electronic components and sensors as well as structural components. One type of ultra lightweight material of great interest is aerogels, which have densities ranging from 0.003 g/cc to 0.8 g/cc . However, aerogels are extremely fragile and, as a result, have limited practical applications. Recently, Glenn Research Center has developed a process of nano-casting polymers onto the inorganic network of silica-based aerogels increasing the strength 300 fold while only increasing the density 3 fold. By combining the process of nano-casting polymers with inorganic oxide networks other than silica, we are actively pursuing lightweight dual purpose materials. To date, thirty different inorganic oxide aerogels have been prepared using either standard sol-gel chemistry or a non-alkoxide method involving metal chloride precursors and an epoxide; epichlorohydrin, propylene oxide or trimethylene oxide, as proton scavengers. More importantly, preliminary investigations show that the residual surface hydroxyl groups on each of these inorganic oxide aerogels can be successfully crosslinked with urethane. In addition to characterizing physical and mechanical properties such as density, strength and flexibility, each of these metal oxide aerogels are being characterized for thermal and electronic conductivity and magnetic and optical properties.

Vassilaras, Plousia E.

2004-01-01

234

June 20-21, 2005 Overview of Chamber/Blanket Work  

E-print Network

20-21, 2005 6 HAPL Thermal Insulation Between Li and FS Wall Required to Minimize Heat Flow From High. A baseline case with minimum risk in getting there based on present day material development and knowledge of what could be gained with a more ambitious material R&D program. · Three blanket options 1. Self

Raffray, A. René

235

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

2014-11-01

236

Production of hollow aerogel microspheres  

SciTech Connect

A process is described for preparing hollow aerogel microspheres, comprising the steps of: reacting metal alkoxide with water and base catalyst in alcohol solvent until a viscous alcogel is attained; forming a drop of viscous alcogel; injecting inert gas and base catalyst into the drop, at the time of drop formation, to form a hollow alcogel microsphere; blowing the hollow alcogel microsphere free of the viscous alcogel to fall into an atmosphere of inert gas and base catalyst; capturing said hollow alcogel microsphere on foam; and subjecting said hollow alcogel microsphere to supercritical drying to form a hollow aerogel microsphere of 800-1,200 [mu]m diameter with a wall thickness of 100-300 [mu]m and a wall density of 0.03 to 0. 3 g/cm[sup 3].

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

1993-07-13

237

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

238

High-Tech, Low-Temp Insulation  

NASA Technical Reports Server (NTRS)

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

1998-01-01

239

Control of mesoporous structure of organic and carbon aerogels  

Microsoft Academic Search

Resorcinol-formaldehyde (RF) aerogels were synthesized via the sol-gel polycondensation of resorcinol with formaldehyde in a slightly basic aqueous solution and followed by supercritical drying with carbon dioxide. Mesoporous carbon aerogels were then obtained by pyrolyzing the RF aerogels in an inert atmosphere. The control of mesoporous structure of the aerogels was studied by changing the amount of resorcinol (R), formaldehyde

H. Tamon; H. Ishizaka; T. Araki; M. Okazaki

1998-01-01

240

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

241

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

242

Structure of random porous materials: Silica aerogel  

Microsoft Academic Search

Using small-angle x-ray scattering, we show that porous silica aerogel has a fractal backbone structure. The observed structure is traced to the underlying chemical (polymerization) and physical (colloid aggregation) growth processes. Comparison of scattering curves for aerogel with silica aggregates confirms this interpretation.

Dale Schaefer; Keith Keefer

1986-01-01

243

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

244

Carbon aerogels for catalysis applications: An overview  

Microsoft Academic Search

Carbon aerogels are nanostructured carbons obtained from the carbonization of organic aerogels, which are prepared from the sol–gel polycondensation of certain organic monomers. These materials have a great versatility both at the nanoscopic level in terms of their pore texture and at the macroscopic level in terms of their form. Thus, the surface area, pore volume, and pore size distribution

C. Moreno-Castilla; F. J. Maldonado-Hódar

2005-01-01

245

Silica aerogel captures cosmic dust intact  

Microsoft Academic Search

The mesostructure of silica aerogel resembles strings of pearls, ranging in size from 10 to 100 Å. This fine mesostructure transmits nearly 90% of incident light in the visible, while providing sufficiently gentle dissipation of the kinetic energy of hypervelocity cosmic dust particles to permit their intact capture. In 1987, silica aerogel was introduced as a capture medium to take

Peter Tsou

1995-01-01

246

Aerogel composites using chemical vapor infiltration  

Microsoft Academic Search

A new method to produce novel composite materials based on the use of aerogels as a starting material is described. Using chemical vapor infiltration, a variety of solid materials were thermally deposited into the open pore structure of aerogel. The resulting materials possess new and unusual properties including photoluminescence, magnetism and altered optical properties. An important characteristic of this preparation

Arlon J. Hunt; Michael R. Ayers; Wanqing Cao

1995-01-01

247

Solid phase microextraction device using aerogel  

DOEpatents

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

Miller, Fred S.; Andresen, Brian D.

2005-06-14

248

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

249

Physics of Interplanetary Dust Collection with Aerogel  

NASA Technical Reports Server (NTRS)

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 capture of particles on the STARDUST mission. In particular, the viscosity of shocked aerogel has been an open question. The results presented here suggest that the viscosity of aerogel at high impact velocities is negligible, although there remains some uncertainty about lower velocities. The model adopted for viscosity treats the mixture of polymeric silica and decomposition products and finds that, for particle velocities of 6-7 km/s, the viscosity is similar to that typical of light gasses at STP. Expressions for the Hugoniot of aerogel as a function of density were also obtained from the available data. All aerogels of interest for cosmic dust collectors have very similar shock velocity-particle velocity Hugoniot curves. The strength behavior of aerogel for low-speed penetration was measured, but further work is needed to study the proper way to apply this to the issue of terminal deceleration of a dust particle. Preliminary calculations designed to maximize the penetration depths were performed to determine the required density of aerogel to reliably stop a particle in a 3 cm thickness of aerogel (the path length expected for a normal impact into the STARDUST collector). In order to stop a particle of density rho(sub p) and diameter d(sub p), the mean density of the aerogel collector should be no less than that given by the expression bar rho(sub 0) = 1.085 X 10(exp -4 )rho(sub p)d(sub p), for densities measured in g/ cu cm and the particle diameter measured in micrometers.

Anderson, William W.

1998-01-01

250

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

251

High Specific Surface area Aerogel Cryoadsorber for Vacuum Pumping Applications  

SciTech Connect

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.; Fought, Eric R.; Biltoft, Peter J.

1998-12-22

252

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

253

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

SciTech Connect

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

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

1998-04-01

254

Mechanically strong, flexible polyimide aerogels cross-linked with aromatic triamine.  

PubMed

Polyimide gels are produced by cross-linking anhydride capped polyamic acid oligomers with aromatic triamine in solution and chemically imidizing. The gels are then supercritically dried to form nanoporous polyimide aerogels with densities as low as 0.14 g/cm(3) and surface areas as high as 512 m(2)/g. To understand the effect of the polyimide backbone on properties, aerogels from several combinations of diamine and dianhydride, and formulated oligomer chain length are examined. Formulations made from 2,2'-dimethylbenzidine as the diamine shrink the least but have among the highest compressive modulus. Formulations made using 4,4'-oxydianiline or 2,2'dimethylbenzidine can be fabricated into continuous thin films using a roll to roll casting process. The films are flexible enough to be rolled or folded back on themselves and recover completely without cracking or flaking, and have tensile strengths of 4-9 MPa. Finally, the highest onset of decomposition (above 600 °C) of the polyimide aerogels was obtained using p-phenylene diamine as the backbone diamine with either dianhydride studied. All of the aerogels are suitable candidates for high-temperature insulation with glass transition temperatures ranging from 270-340 °C and onsets of decomposition from 460-610 °C. PMID:22233638

Meador, Mary Ann B; Malow, Ericka J; Silva, Rebecca; Wright, Sarah; Quade, Derek; Vivod, Stephanie L; Guo, Haiquan; Guo, Jiao; Cakmak, Miko

2012-02-01

255

Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation  

NASA Technical Reports Server (NTRS)

The primary application for cryogenic insulating foams will be fuel tank applications for fueling systems. It is crucial for this insulation to be incorporated into systems that survive vacuum and terrestrial environments. It is hypothesized that by forming an open-cell silica-reinforced polymer structure, the foam structures will exhibit the necessary strength to maintain shape. This will, in turn, maintain the insulating capabilities of the foam insulation. Besides mechanical stability in the form of crush resistance, it is important for these insulating materials to exhibit water penetration resistance. Hydrocarbon-terminated foam surfaces were implemented to impart hydrophobic functionality that apparently limits moisture penetration through the foam. During the freezing process, water accumulates on the surfaces of the foams. However, when hydrocarbon-terminated surfaces are present, water apparently beads and forms crystals, leading to less apparent accumulation. The object of this work is to develop inexpensive structural cryogenic insulation foam that has increased impact resistance for launch and ground-based cryogenic systems. Two parallel approaches will be pursued: a silica-polymer co-foaming technique and a post foam coating technique. Insulation characteristics, flexibility, and water uptake can be fine-tuned through the manipulation of the polyurethane foam scaffold. Silicate coatings for polyurethane foams and aerogel-impregnated polyurethane foams have been developed and tested. A highly porous aerogel-like material may be fabricated using a co-foam and coated foam techniques, and can insulate at liquid temperatures using the composite foam

Hess, David M.

2013-01-01

256

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

257

MHD pressure drops and thermal hydraulic analysis for the ITER breeding blanket design  

SciTech Connect

The breeding blanket design of the International Thermonuclear Experimental Reactor (ITER) is a self-cooled liquid lithium system with a vanadium structure. Electrical insulation of the coolant channel surfaces from the liquid metal is required to reduce the magnetohydrodynamic (MHD) pressure to less than 1 MPa. Insulation is provided by AIN coating at the channel surfaces in contact with lithium. MHD pressure drop and thermal hydraulic analysis of the blanket design is carried out subject to pressure, temperature, and stress considerations. Design windows relating the lithium flow velocity, MHD pressure, and structural temperature are formulated. The requirements of the insulator coating and characterization of the coating effectiveness are presented. Effects on the MHD pressure drop due to uniform cracks through the coating layer is also analyzed.

Hua, Thanh Q. [Argonne National Lab., IL (United States); Gohar, Y. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany). International Thermonuclear Experimental Reactor (ITER)

1994-06-01

258

Aerogel Projects Ongoing in MSFC's Engineering Directorate  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

259

The blanket interface to TSTA  

SciTech Connect

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

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

1988-09-01

260

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

NASA Astrophysics Data System (ADS)

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

Liu, Xipeng

2005-11-01

261

Lightweight Thermal Insulation for a Liquid-Oxygen Tank  

NASA Technical Reports Server (NTRS)

A proposed lightweight, reusable thermal-insulation blanket has been designed for application to a tank containing liquid oxygen, in place of a non-reusable spray-on insulating foam. The blanket would be of the multilayer-insulation (MLI) type and equipped with a pressure-regulated nitrogen purge system. The blanket would contain 16 layers in two 8-layer sub-blankets. Double-aluminized polyimide 0.3 mil (.0.008 mm) thick was selected as a reflective shield material because of its compatibility with oxygen and its ability to withstand ionizing radiation and high temperature. The inner and outer sub-blanket layers, 1 mil (approximately equals 0.025 mm) and 3 mils (approximately equals 0.076 mm) thick, respectively, would be made of the double-aluminized polyimide reinforced with aramid. The inner and outer layers would provide structural support for the more fragile layers between them and would bear the insulation-to-tank attachment loads. The layers would be spaced apart by lightweight, low-thermal-conductance netting made from polyethylene terephthalate.

Willen, G. Scott; Lock, Jennifer; Nieczkoski, Steve

2005-01-01

262

Facile preparation of monolithic ?-carrageenan aerogels.  

PubMed

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

Ganesan, Kathirvel; Ratke, Lorenz

2014-05-14

263

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

264

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

NASA Technical Reports Server (NTRS)

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

Sullivan, Thomas A. (Inventor)

2007-01-01

265

Synthesis and characterization of vanadium oxide aerogels  

Microsoft Academic Search

Vanadium pentoxide aerogels were synthesized by supercritical drying with CO2. The aerogels were prepared using a variety of sol compositions from the system VO(OC3H7)3\\/H2O\\/acetone. The materials were found to be of fairly low density (0.04-0.1 g\\/cm3) with surface areas in the range of 300–400 m2\\/g. Chemical and structural studies indicate that the aerogels are hydrated oxides of composition V2O5 ·

F. Chaput; B. Dunn; P. Fuqua; K. Salloux

1995-01-01

266

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

267

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

268

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

269

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

270

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

271

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

272

Low density, resorcinol-formaldehyde aerogels  

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1989-01-01

273

Low density, resorcinol-formaldehyde aerogels  

DOEpatents

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

Pekala, Richard W. (Pleasant Hill, CA)

1991-01-01

274

Low density, resorcinol-formaldehyde aerogels  

DOEpatents

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

Pekala, R.W.

1989-10-10

275

Low density, resorcinol-formaldehyde aerogels  

DOEpatents

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

Pekala, R.W.

1988-05-26

276

Carbon aerogel electrodes for direct energy conversion  

DOEpatents

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 a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome.

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

1997-01-01

277

Carbon aerogel electrodes for direct energy conversion  

DOEpatents

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 connected to a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome. 1 fig.

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

1997-02-11

278

Ruthenium / aerogel nanocomposits via Atomic Layer Deposition  

SciTech Connect

We present a general approach to prepare metal/aerogel nanocomposites via template directed atomic layer deposition (ALD). In particular, we used a Ru ALD process consisting of alternating exposures to bis(cyclopentadienyl)ruthenium (RuCp{sub 2}) and air at 350 C to deposit metallic Ru nanoparticles on the internal surfaces of carbon and silica aerogels. The process does not affect the morphology of the aerogel template and offers excellent control over metal loading by simply adjusting the number of ALD cycles. We also discuss the limitations of our ALD approach, and suggest ways to overcome these.

Biener, J; Baumann, T F; Wang, Y; Nelson, E J; Kucheyev, S O; Hamza, A V; Kemell, M; Ritala, M; Leskela, M

2006-08-28

279

European testing blanket modules auxiliaries design  

Microsoft Academic Search

The design of the auxiliary systems for the two European Test Blanket Modules is an important engineering task that will allow the successful integration of the two DEMO Blanket mock-ups into the ITER machine, and, through these experiments, demonstrate the technological feasibility of a blanket module for a future fusion power plant.These auxiliary systems are mainly circuits devoted to the

A. Aiello; A. Ciampichetti; F. Cismondi; B. E. Ghidersa; Tamas Ilkei; L. Kosek; J. F. Salavy

2011-01-01

280

Multiplier, moderator, and reflector materials for lithium-vanadium fusion blankets.  

SciTech Connect

The self-cooled lithium-vanadium fusion blanket concept has several attractive operational and environmental features. In this concept, liquid lithium works as the tritium breeder and coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because of its superior performance relative to other alloys for this application. However, this concept has poor attenuation characteristics and energy multiplication for the DT neutrons. An advanced self-cooled lithium-vanadium fusion blanket concept has been developed to eliminate these drawbacks while maintaining all the attractive features of the conventional concept. An electrical insulator coating for the coolant channels, spectral shifter (multiplier, and moderator) and reflector were utilized in the blanket design to enhance the blanket performance. In addition, the blanket was designed to have the capability to operate at high loading conditions of 2 MW/m{sup 2} surface heat flux and 10 MW/m{sup 2} neutron wall loading. This paper assesses the spectral shifter and the reflector materials and it defines the technological requirements of this advanced blanket concept.

Gohar, Y.; Smith, D. L.

1999-10-07

281

Insulation Station  

NSDL National Science Digital Library

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

Twin Cities Public Television

2013-01-01

282

Ceramic Aerogel Composite Materials and Characterization  

NASA Technical Reports Server (NTRS)

Aerogels a.k.a "Solid Smoke" are gels with the liquid phase replaced by gas, leaving behind a highly porous material with a nanoscale framework. Due to the porous, nanoscale structure, aerogels have the lowest known density and conductivity of solids. Aerogels have the potential for being a breakthrough material because of their extremely light weight and unique properties. In this paper, we address overcoming their most profound weaknesses: mechanical fragility and very high surface activity, which leads to a lowered sintering temperature. A matrix of ceramic aerogel composite materials was produced to investigate their properties and functionality. Mechanical property measurements and Scanning Electron Micrographs are used to identify trends and structure of these ceramic composite materials. Thermal cycling was used to identify the sintering points of the materials.

White, Susan; Hrubesh, Lawrence W.; Rasky, Daniel J. (Technical Monitor)

1997-01-01

283

Tortuosity of 4He Films on Aerogel  

SciTech Connect

A torsional oscillator has been used to study the flow of liquid 4He through silica aerogel. The tortuosity and dissipation of the flow in the fractal aerogel environment has been measured, for both capillary condensed films and a fully saturated cell. The scaling of tortuosity as a function of filling fraction has been investigated. We compare the results of our 88%-porous aerogel to a 92%-porous sample where a transverse sound technique was used. Our more sensitive technique has reduced the scatter in both the frequency and dissipation data. Like in the previous transverse sound experiment, we find tortuosity as a function of filling fraction to scale with an exponent of {approx} -1.1. Further experiments are planned, to find the dependence of the exponent on the fractal dimension and porosity of aerogel.

Ashton, C. E.; Golov, A. I. [School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Mulders, N. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)

2006-09-07

284

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

285

Alumina aerogels prepared via rapid supercritical extraction  

Microsoft Academic Search

Alumina aerogels with surface areas from 460 to 840 m2\\/g and bulk densities from 0.025 to 0.079 g\\/cm3 were successfully fabricated using variations of an aluminum isopropoxide-based recipe developed by Armor and Carlson and\\u000a the rapid supercritical extraction (RSCE) process developed at Union College. By utilizing the Union College RSCE method,\\u000a it is possible to convert an alumina aerogel precursor mixture into

Michael S. Bono Jr; Ann M. Anderson; Mary K. Carroll

2010-01-01

286

Process for preparing polymer reinforced silica aerogels  

NASA Technical Reports Server (NTRS)

Process for preparing polymer-reinforced silica aerogels which comprises a one-pot reaction of at least one alkoxy silane in the presence of effective amounts of a polymer precursor to obtain a silica reaction product, the reaction product is gelled and subsequently subjected to conditions that promotes polymerization of the precursor and then supercritically dried to obtain the polymer-reinforced monolithic silica aerogels.

Meador, Mary Ann B. (Inventor); Capadona, Lynn A. (Inventor)

2011-01-01

287

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

288

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

289

Anisotropic high-surface-area carbon aerogels  

Microsoft Academic Search

The subject of this paper is the investigation of the multiscale structure of a new series of carbon aerogels. These carbon aerogels are obtained by resorcinol resorcinol–formaldehyde sol–gel reactions in acetone in a single-step base catalysis (AB) or a double-step base–acid catalysis (ABA) followed by supercritical drying and pyrolysis at 1050°C under nitrogen flow. Two complementary techniques were used: small-angle

Sandrine Berthon-Fabry; David Langohr; Patrick Achard; Daniel Charrier; David Djurado; Françoise Ehrburger-Dolle

2004-01-01

290

High Temperature Aerogels for Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

High temperature aerogels in the Al2O3-SiO2 system are being investigated as possible constituents for lightweight integrated thermal protection system (TPS) designs for use in supersonic and hypersonic applications. Gels are synthesized from ethoxysilanes and AlCl3.6H2O, using an epoxide catalyst. The influence of Al:Si ratio, solvent, water to metal and water to alcohol ratios on aerogel composition, morphology, surface area, and pore size distribution were examined, and phase transformation on heat treatment characterized. Aerogels have been fabricated which maintain porous, fractal structures after brief exposures to 1000 C. Incorporation of nanofibers, infiltration of aerogels into SiC foams, use of polymers for crosslinking the aerogels, or combinations of these, offer potential for toughening and integration of TPS with composite structure. Woven fabric composites having Al2O3-SiO2 aerogels as a matrix also have been fabricated. Continuing work is focused on reduction in shrinkage and optimization of thermal and physical properties.

Hurwitz, Frances I.; Mbah, Godfrey C.

2008-01-01

291

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

292

Synthesis and characterization of a nanocrystalline diamond aerogel  

SciTech Connect

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.

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

2011-07-06

293

Regeneration of Carbon Aerogel Exhausted in Water Purification  

E-print Network

Carbon has been used electrochemically in various forms for water treatment and the carbon aerogel is one of them. Carbon Aerogels (CA) are used as electrodes due to their high surface capacity and high electrical conductivity. They are also known...

Tewari, Sanjay

2012-02-14

294

Durable polymer-aerogel based superhydrophobic coatings, a composite material  

DOEpatents

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

Kissel, David J; Brinker, Charles Jeffrey

2014-03-04

295

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

296

Thermal Performance Testing of Cryogenic Insulation Systems  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

297

Effect of preparation method on electrochemical property of Mn-doped carbon aerogel for supercapacitor  

Microsoft Academic Search

To investigate the effect of preparation method on electrochemical properties, Mn-doped carbon aerogels were prepared using monolith carbon aerogel and carbon aerogel powder. For this purpose, Mn-doped carbon aerogels (Mn-doped monolith carbon aerogel and Mn-doped carbon aerogel powder) were prepared by two different wet impregnation methods. Electrochemical properties of Mn-doped carbon aerogel electrodes were investigated by cyclic voltammetry and galvanostatic

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

2011-01-01

298

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

299

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

300

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

Microsoft Academic Search

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

L. W Hrubesh; J. F Poco

1995-01-01

301

Controllability of pore characteristics of resorcinol–formaldehyde carbon aerogel  

Microsoft Academic Search

Resorcinol–formaldehyde (RF) aerogels were synthesized by sol–gel polycondensation of resorcinol with formaldehyde in a slightly basic aqueous solution, followed by drying with supercritical carbon dioxide. The RF carbon aerogels were prepared by carbonizing the RF aerogels at a high temperature under a nitrogen atmosphere. On changing the catalyst species and the catalyst ratios in synthesizing the RF hydrogels, we investigated

Toshihide Horikawa; Jun'ichi Hayashi; Katsuhiko Muroyama

2004-01-01

302

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.

303

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

304

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

305

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

306

Thermomechanical analysis of the ITER breeding blanket  

SciTech Connect

Thermomechanical performance of the ITER breeding blanket is an important design issue because it requires first, that the thermal expansion mismatch between the blanket structure and the blankets internals (such as, beryllium multiplier and tritium breeders) can be accommodated without creating high stresses, and second, that the thermomechanical deformation of various interfaces within the blanket does not create high resistance to heat flow and consequent unacceptably high temperatures in the blanket materials. Thermomechanical analysis of a single beryllium block sandwiched between two stainless steel plates was carried out using the finite element code ABAQUS to illustrate the importance of elastic deformation on the temperature distributions. Such an analysis for the whole ITER blanket needs to be conducted in the future. Uncertainties in the thermomechanical contact analysis can be reduced by bonding the beryllium blocks to the stainless steel plates by a thin soft interfacial layer.

Majumdar, S.; Gruhn, H. [Argonne National Lab., IL (United States); Gohar, Y.; Giegerich, M. [Max-Planck-Institut fuer Plasmaphysik, Muenchen (Germany). ITER Joint Central Team

1997-03-01

307

Hydrogen crystallization in low-density aerogels.  

PubMed

Crystallization of liquids confined in disordered low-density nanoporous scaffolds is poorly understood. Here, we use relaxation calorimetry to study the liquid-solid phase transition of H2 in a series of silica and carbon (nanotube- and graphene-based) aerogels with porosities ?94%. Results show that freezing temperatures of H2 inside all the aerogels studied are depressed but do not follow predictions of the Gibbs-Thomson theory based on average pore diameters measured by conventional gas sorption techniques. Instead, we find that, for each material family investigated, the depression of average freezing temperatures scales linearly with the ratio of the internal surface area (measured by gas sorption) and the total pore volume derived from the density of aerogel monoliths. The slope of such linear dependences is, however, different for silica and carbon aerogels, which we attribute to microporosity of carbons and the presence of macropores in silica aerogels. Our results have important implications for the analysis of pore size distributions of low-density nanoporous materials and for controlling crystallization of fuel layers in targets for thermonuclear fusion energy applications. PMID:25781182

Kucheyev, S O; Van Cleve, E; Johnston, L T; Gammon, S A; Worsley, M A

2015-04-01

308

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

309

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

310

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

311

Low technology high tritium breeding blanket concept  

SciTech Connect

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

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

1987-10-01

312

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

313

75 FR 11557 - Woven Electric Blankets From China  

Federal Register 2010, 2011, 2012, 2013, 2014

...No. 731-TA-1163 (Final)] Woven Electric Blankets From China AGENCY: United States...less-than-fair-value imports from China of woven electric blankets, provided for in subheading...semi- finished, and unassembled woven electric blankets, including woven electric...

2010-03-11

314

The impregnated synthesis of polypyrrole into carbon aerogel and its applications to photovoltaic materials  

Microsoft Academic Search

Carbon aerogels were prepared by pyrolyzing resorcinol and formaldehyde polycondensates, which were obtained in aerogel form by supercritical drying with carbon dioxide. Polypyrrole was impregnated into the carbon aerogels to prepare the carbon\\/polypyrrole nanocomposites, in which the pyrrole had penetrated the micropores of the carbon aerogels under a reduced pressure and then was polymerized by chemical oxidation. The carbon aerogels

Pil-Ho Kim; Jeong-Don Kwon; Jeong Soo Kim

2004-01-01

315

Nucleation and Avalanche of 4He Crystals in Aerogel  

NASA Astrophysics Data System (ADS)

Dynamical transition of 4He crystals in aerogel was reported recently (Nomura et al. Phys. Rev. Lett. 101:175703, 2008). Bare aerogel, which was placed in the bulk 4He crystals, was used in the report. 4He crystals inside the aerogel grew via creep at high temperatures and via avalanche at low temperatures owing to the competition between thermal fluctuation and quenched disorder. Crystal-liquid interface advanced from the edge to inside of the aerogel. Crystal has a greater density than liquid so that the extra mass has to be transported in the crystallization process. It is not known how the mass is transported in the aerogel. To find a clue to this issue, we did an experiment with aerogel in a glass tube so that the aerogel had contact with the bulk on only one surface. In this case, a similar dynamical transition was observed at low temperatures. In the avalanche region, however, 4He crystals did not grow from the outer surface of the aerogel but nucleated at various sites inside the aerogel. This means that crystallization in aerogel does not occur by the forced invasion of 4He crystal but by a process of the bulk crystal once being melted and transported to increase the pressure of the liquid in the aerogel. Thus, a mass transport mechanisms for the crystallization has been revealed by this observation.

Ueno, Ken-Ichi; Masumoto, Ryota; Mimori, Tomohiro; Osawa, Aiko; Nomura, Ryuji; Okuda, Yuichi

2010-02-01

316

Reversible toluene adsorption on monolithic carbon aerogels.  

PubMed

Thirteen monolithic carbon aerogels with different pore textures were used as toluene adsorbents. Adsorption was carried out under both static and dynamic conditions. Under static conditions at 25 degrees C and at saturation, an adsorption capacity as high as 1.36 cm(3) g(-1) or 1180 mg g(-1) was obtained. Toluene adsorption was a reversible process in all carbon aerogels, and the adsorbed toluene was completely recovered by heating them at 400 degrees C. Regenerated adsorbents showed larger surface area and micropore width than the original samples, indicating that no pore blockage was produced. Adsorption under dynamic conditions at 100 degrees C was also completely reversible after at least three consecutive adsorption-desorption cycles. The ability of these carbon aerogels to reversibly adsorb toluene could be useful for their application in thermal swing adsorption or pressure swing adsorption equipment. PMID:17433536

Maldonado-Hódar, Francisco J; Moreno-Castilla, Carlos; Carrasco-Marín, Francisco; Pérez-Cadenas, Agustín F

2007-09-30

317

High strength air-dried aerogels  

DOEpatents

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

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

2012-11-06

318

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

319

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

NASA Technical Reports Server (NTRS)

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

Good, Brian

2009-01-01

320

Incorporation of noble metals into aerogels  

DOEpatents

Aerogels or xerogels containing atomically dispersed noble metals for applications such as environmental remediation are disclosed. New noble metal precursors, such as Pt--Si or Pd(Si--P){sub 2}, have been created to bridge the incompatibility between noble metals and oxygen, followed by their incorporation into the aerogel or xerogel through sol-gel chemistry and processing. Applications include oxidation of hydrocarbons and reduction of nitrogen oxide species, complete oxidation of volatile organic carbon species, oxidative membranes for photocatalysis and partial oxidation for synthetic applications.

Hair, L.M.; Sanner, R.D.; Coronado, P.R.

1998-12-22

321

Development 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. This report discusses the requirements of the International Thermonuclear Experimental Reactor for a self-cooled blanket that uses liquid Li and for indirectly cooled blankets that use other alkali metals such as NaK. The report discusses 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. The report addresses the thermodynamics of interactions between the liquid metals (e.g., Li and NaK) and structural materials (e.g., V-base alloys and Type 316 stainless steel) and the AlN candidate electrical insulator coating, together with associated corrosion/compatibility issues. Details are presented on the AlN coating fabrication methods, and experimental data are reported for microstructures, pretreatment of the substrate, and heat treatment of coatings, coating/substrate and coating/lithium interactions, and electrical resistance before and after exposure to lithium.

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

1995-01-01

322

The breeder blanket interface (BBI) to TSTA  

SciTech Connect

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

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

1989-03-01

323

Manufacturing complex silica aerogel target components  

SciTech Connect

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

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

2008-01-01

324

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

325

Methods of making glass wool blowing insulation  

SciTech Connect

A process is described of making pieces of glass wool, suitable to be blown into attics as thermal insulation, from an elongated generally laminar resiliently compressible glass wool blanket having an original thickness in an unrestrained condition and made of glass fibers bonded with thermoset resin. The process comprises feeding the blanket longitudinally through a compressing station where it is resiliently compressed from its original thickness to a smaller thickness, and feeding the compressed blanket longitudinally between a rotating backup roll and a cooperative rotating cutting roll from one side of the rolls, the cutting roll including a supporting cylinder. A plywood blade-mounting cylinder is mounted on the supporting cylinder, circular cutting blades each have shank portions spaced from each other and disposed substantially completely around an inner periphery of the blade. Straight cutting blades have shank portions spaced from each other and disposed substantially completely along a length of the blade. Resiliently compressible plugs, the circular cutting blades respectively are separately mounted on the plywood cylinder circumferentially distributed substantially throughout the length spaced equally from each other axially by a distance smaller than the original thickness of the blanket, and having their shank portions mounted respectively in slits extending substantially all the way through a wall thickness of the plywood cylinder. The straight cutting blades respectively are separatedly mounted on the plywood cylinder axially distributed throughout the circumference.

Johnson, A.R.; Yawberg, R.C.

1987-07-28

326

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

327

Multivariable optimization of fusion reactor blankets  

SciTech Connect

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

Meier, W.R.

1984-04-01

328

Evaluating Dimethyldiethoxysilane for use in Polyurethane Crosslinked Silica Aerogels  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

329

Load responsive multilayer insulation performance testing  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

330

Load responsive multilayer insulation performance testing  

SciTech Connect

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

Dye, S.; Kopelove, A. [Quest Thermal Group, 6452 Fig Street Suite A, Arvada, CO 80004 (United States); Mills, G. L. [Ball Aerospace and Technologies Corp, 1600 Commerce Street, Boulder, CO 80301 (United States)

2014-01-29

331

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

332

The ITER blanket system design challenge  

NASA Astrophysics Data System (ADS)

This paper summarizes the latest progress in the ITER blanket system design as it proceeds through its final design phase with the Final Design Review planned for Spring 2013. The blanket design is constrained by demanding and sometime conflicting design and interface requirements from the plasma and systems such as the vacuum vessel, in-vessel coils and blanket manifolds. This represents a major design challenge, which is highlighted in this paper with examples of design solutions to accommodate some of the key interface and integration requirements.

Raffray, A. R.; Calcagno, B.; Chappuis, P.; Fu, Zhang; Furmanek, A.; Jiming, Chen; Kim, D.-H.; Khomiakov, S.; Labusov, A.; Martin, A.; Merola, M.; Mitteau, R.; Sadakov, S.; Ulrickson, M.; Zacchia, F.; Contributors from the Blanket Integrated Product Team

2014-03-01

333

Catalytic graphitization of carbon aerogels by transition metals  

Microsoft Academic Search

Carbon aerogels and Cr-, Fe-, Co-, and Ni-containing carbon aerogels were obtained by pyrolysis, at temperatures between 500 and 1,800 C, of the corresponding aerogels prepared by the sol-gel method from polymerization of resorcinol with formaldehyde. All samples were characterized by mercury porosimetry, nitrogen adsorption, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. Results obtained show that

F. J. Maldonado-Hodar; C. Moreno-Castilla; J. Rivera-Utrilla; Y. Hanzawa; Y. Yamada

2000-01-01

334

Energy loss and impact cratering in aerogels: theory and experiment  

Microsoft Academic Search

Aerogel collectors have been deployed in low-Earth orbit to collect orbital debris and micrometeorites. An array of silica aerogel collectors is currently en-route back to Earth following an encounter with the Comet Wild-2 on board the Stardust spacecraft. Stardust is returning, for laboratory analysis, cometary and interstellar dust grains which impacted into the aerogel collectors at hypervelocities. While the morphology

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

2004-01-01

335

Vibration Considerations for Cryogenic Tanks Using Glass Bubbles Insulation  

NASA Technical Reports Server (NTRS)

The use of glass bubbles as an efficient and practical thermal insulation system has been 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 has been reduced by approximately 50 percent. Further applications may include non-stationary tanks such as mobile tankers and tanks with extreme duty cycles or exposed to significant vibration environments. Space rocket launch events and mobile tanker life cycles represent two harsh cases of mechanical vibration exposure. A number of bulk fill insulation materials including glass bubbles, perlite powders, and aerogel granules were tested for vibration effects and mechanical behavior using a custom design holding fixture subjected to random vibration on an Electrodynamic Shaker. The settling effects for mixtures of insulation materials were also investigated. The vibration test results and granular particle analysis are presented with considerations and implications for future cryogenic tank applications. A thermal performance update on field demonstration testing of a 218,000 L liquid hydrogen storage tank, retrofitted with glass bubbles, is presented. KEYWORDS: Glass bubble, perlite, aerogel, insulation, liquid hydrogen, storage tank, mobile tanker, vibration.

Werlink, Rudolph J.; Fesmire, James E.; Sass, Jared P.

2011-01-01

336

Insulation Material  

NASA Technical Reports Server (NTRS)

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

1984-01-01

337

Membranes Improve Insulation Efficiency  

E-print Network

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

Bullock, C. A.

1986-01-01

338

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

SciTech Connect

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

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

1983-09-01

339

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

340

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

341

Thio-,amine-,nitro-,and macrocyclic containing organic aerogels & xerogels  

DOEpatents

An organic aerogel or xerogel formed by a sol-gel reaction using starting materials that exhibit similar reactivity to the most commonly used resorcinol starting material. The new starting materials, including thio-, amine- and nitro-containing molecules and functionalized macrocyclic molecules will produce organic xerogels and aerogels that have improved performance in the areas of detection and sensor technology, as well as water stream remediation. Also, further functionalization of these new organic aerogels or xerogels will yield material that can be extracted with greater facility than current organic aerogels.

Fox, Glenn A.; Tillotson, Thomas M.

2005-08-02

342

Polysaccharide-based aerogel microspheres for oral drug delivery.  

PubMed

Polysaccharide-based aerogels in the form of microspheres were investigated as carriers of poorly water soluble drugs for oral administration. These bio-based carriers may combine the biocompatibility of polysaccharides and the enhanced drug loading capacity of dry aerogels. Aerogel microspheres from starch, pectin and alginate were loaded with ketoprofen (anti-inflammatory drug) and benzoic acid (used in the management of urea cycle disorders) via supercritical CO2-assisted adsorption. Amount of drug loaded depended on the aerogel matrix structure and composition and reached values up to 1.0×10(-3) and 1.7×10(-3) g/m(2) for ketoprofen and benzoic acid in starch microspheres. After impregnation, drugs were in the amorphous state in the aerogel microspheres. Release behavior was evaluated in different pH media (pH 1.2 and 6.8). Controlled drug release from pectin and alginate aerogel microspheres fitted Gallagher-Corrigan release model (R(2)>0.99 in both cases), with different relative contribution of erosion and diffusion mechanisms depending on the matrix composition. Release from starch aerogel microspheres was driven by dissolution, fitting the first-order kinetics due to the rigid starch aerogel structure, and showed different release rate constant (k1) depending on the drug (0.075 and 0.160 min(-1) for ketoprofen and benzoic acid, respectively). Overall, the results point out the possibilities of tuning drug loading and release by carefully choosing the polysaccharide used to prepare the aerogels. PMID:25498702

García-González, C A; Jin, M; Gerth, J; Alvarez-Lorenzo, C; Smirnova, I

2015-03-01

343

Polyimide aerogels with amide cross-links: a low cost alternative for mechanically strong polymer aerogels.  

PubMed

Polyimide aerogels combine high porosity, low thermal conductivity, flexibility, and low density with excellent mechanical properties. However, previously used cross-linkers, such as 1,3,5-triaminophenoxybenzene (TAB), 2,4,6-tris(4-aminophenyl)pyridine (TAPP), or octa(aminophenoxy)silsesquioxane (OAPS), either are not commercially available or are prohibitively expensive. Finding more cost efficient cross-linkers that are commercially available to synthesize these aerogels is crucial for making large scale manufacturing attractive. Herein, we describe an approach to making polyimide aerogels starting with amine capped oligomers that are cross-linked with 1,3,5-benzenetricarbonyl trichloride (BTC). BTC is a lower cost, commercially available alternative to TAB, TAPP, or OAPS. Aerogels made in this way have the same or higher modulus and higher surface area compared to those previously reported with either TAB or OAPS cross-links at the same density. While the cross-link structure is an amide, the thermal stability is not compromised most likely because the cross-link is only a small part of the composition of the aerogel. Onset of decomposition depends primarily on the backbone chemistry with 4,4'-oxidianiline (ODA) being more thermally stable than 2,2'-dimethylbenzidine (DMBZ), similar to those previously reported with other cross-links. PMID:25564878

Meador, Mary Ann B; Alemán, Christian R; Hanson, Katrina; Ramirez, Nakaira; Vivod, Stephanie L; Wilmoth, Nathan; McCorkle, Linda

2015-01-21

344

Microsphere insulation systems  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

345

APT target-blanket fabrication development  

SciTech Connect

Concepts for producing tritium in an accelerator were translated into hardware for engineering studies of tritium generation, heat transfer, and effects of proton-neutron flux on materials. Small-scale target- blanket assemblies were fabricated and material samples prepared for these performance tests. Blanket assemblies utilize composite aluminum-lead modules, the two primary materials of the blanket. Several approaches are being investigated to produce large-scale assemblies, developing fabrication and assembly methods for their commercial manufacture. Small-scale target-blanket assemblies, designed and fabricated at the Savannah River Site, were place in Los Alamos Neutron Science Center (LANSCE) for irradiation. They were subjected to neutron flux for nine months during 1996-97. Coincident with this test was the development of production methods for large- scale modules. Increasing module size presented challenges that required new methods to be developed for fabrication and assembly. After development, these methods were demonstrated by fabricating and assembling two production-scale modules.

Fisher, D.L.

1997-06-13

346

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

347

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

348

Aerogel keystones: extraction of complete hypervelocity impact events from aerogel collectors  

E-print Network

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.

Andrew J. Westphal; Christopher J. Snead; Anna L. Butterworth; Giles A. Graham; John P. Bradley; Sasa Bajt; Patrick G. Grant; Graham Bench; Sean Brennan; Piero Pianetta

2003-12-17

349

Adsorption studies of Xe on RF Aerogel  

NASA Astrophysics Data System (ADS)

We have conducted an adsorption isotherm study of Xe on RF-aerogel. Measurements were performed at eleven different temperatures between 140 and 87 K. The maximum thickness of the adsorbed films at saturation was determined as a function of isotherm temperature. We found that the maximum film thickness decreases as the temperature is decreased, with a very sharp decrease below 100 K. Projecting the values of the maximum film thickness for temperatures below those measured, we obtained an expected non-wetting temperature for this system of about 80 K. The implications of these results for the interpretation of recent thermal conductivity measurements of Xe films of RF-aerogel will be discussed.

Zambano, Antonio J.; Zhu, Da-Ming; Migone, Aldo D.

2000-03-01

350

Recyclable Solid Blanket for a Fusion Reactor  

NASA Astrophysics Data System (ADS)

Neutron damage and tritium inventory will limit the lifetime of inner wall components of a fusion reactor, leading to increased operation cost and possibly making it economically unattractive. Thick liquid walls may be a solution to this; however, at present the feasibility of forming and maintaining thick liquid walls remains to be demonstrated for a tokamak configuration. Here it is proposed to construct inner wall components of a reactor using a meltable material. During the normal operation the blanket is maintained in the solid state. After some period of operation, when a critical level of neutron damage and tritium inventory in the blanket is accumulated, the structure is melted and drained out of the reactor chamber. After that, by bringing in fresh liquid blanket material and freezing it to the solid state on the walls, the blanket is rebuilt. Thus the blanket is periodically replaced without opening up the reactor chamber, relatively easily compared to a solid blanket. Preliminary calculations demonstrate that such system can satisfy the basic requirements of thermal transport and tritium breeding in a reactor.

Umansky, M. V.

2009-11-01

351

Design of Multilayer Insulation for the Multipurpose Hydrogen Test Bed  

NASA Technical Reports Server (NTRS)

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

Marlow, Weston A.

2011-01-01

352

Carbonates Found in Stardust Aerogel Tracks  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

353

The Pore Structure Determination of Carbon Aerogels  

Microsoft Academic Search

The detailed adsorption isotherms of nitrogen on carbon aerogels at 77 K were measured. The N2 adsorption isotherm had a marked hysteresis. The adsorption isotherms were analyzed by high resolution as-plots to evaluate their porosity. The as-plots showed an explicit upward deviation from the linearity below as = 0.5, suggesting the presence of micropores. The mesoporosity and microporosity were separately

Y. Hanzawa; K. Kaneko; N. Yoshizawa; R. W. Pekala; M. S. Dresselhaus

1998-01-01

354

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 containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

Coronado, Paul R. (Livermore, CA)

1999-01-01

355

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

356

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

357

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

358

Cellulose nanofibrils aerogels generated from jute fibers.  

PubMed

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

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

2014-08-30

359

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

360

Characterization of the microstructures of organic and carbon aerogels based upon mixed cresol–formaldehyde  

Microsoft Academic Search

Organic aerogels were synthesized via the sol–gel polycondensation of mixed cresol with formaldehyde in a slightly basic aqueous solution followed by supercritical drying with carbon dioxide. Carbon aerogels are generated by pyrolysis of organic aerogels in inert atmosphere at high temperature. Obvious chemical and physical changes can take place within aerogel microstructures during the pyrolysis process. IR combined with TGA,

Wen-Cui Li; An-Hui Lu; Shu-Cai Guo

2001-01-01

361

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

362

Effect of concentration of reactants on porosity of hydrogels, organic and carbon aerogels  

Microsoft Academic Search

Hydrogels, organic and carbon aerogels were prepared by sol–gel polymerization of phenolic resole, m-cresol, melamine and formaldehyde followed by supercritical drying and pyrolysis. The roles of concentration of reactants in determining porosity of organic and carbon aerogels were investigated under the same ratios of reactants by extracting porous structural information of hydrogels, organic aerogels and carbon aerogels from small angle

Rui Zhang; Wen Li; Kaixi Li; Chunxiang Lu; Liang Zhan; Licheng Ling

2004-01-01

363

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

SciTech Connect

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

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

1995-08-01

364

Carbon aerogels derived from cresol–resorcinol–formaldehyde for supercapacitors  

Microsoft Academic Search

The objective of the present paper is to demonstrate the possibility to synthesize mixed carbon aerogels (denoted CmRF) from cresol (Cm), resorcinol (R) and formaldehyde (F), as an alternative economic route to the classical RF synthesis. These porous carbon aerogels can be used as electrode materials for supercapacitors with a high volume-specific capacitance. Organic precursor gels were synthesized via polycondensation

Wencui Li; G Reichenauer; J Fricke

2002-01-01

365

Organic aerogels from the polycondensation of resorcinol with formaldehyde  

Microsoft Academic Search

The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer “clusters”. The covalent crosslinking of these “clusters” produces gels which are processed under supercritical conditions to obtain low density, organic aerogels ( ? 0.1 g cm-3). The aerogels are transparent, dark red in colour, and consist of interconnected colloidal-like particles with diameters of

R. W. Pekala

1989-01-01

366

Perspective: Graphene aerogel goes to superelasticity and ultraflyweight  

NASA Astrophysics Data System (ADS)

Three-dimensional graphene-based aerogels have been promoted to present fascinating superelasticity and ultralightness by the intelligent design on microstructures. In this perspective, we conclude the recent design strategies to realize these dual elasticity and lightness, and look forward to the promising applications of graphene-based aerogels with multifunctional merits.

Xu, Zhen; Sun, Haiyan; Gao, Chao

2013-09-01

367

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

368

Aerogel tempelated ZnO dye-sensitized solar cells.  

SciTech Connect

Atomic layer deposition is employed to conformally coat low density, high surface area aerogel films with ZnO. The ZnO/aerogel membranes are incorporated as photoanodes in dye-sensitized solar cells, which exhibit excellent power efficiencies of up to 2.4% under 100 mW cm{sup -2} light intensity.

Hamann, T. W.; Martinson , A. B. E.; Elam, J. W.; Pellin, M. J.; Hupp, J. T.; Materials Science Division; Northwestern Univ.

2008-01-01

369

Acoustic Spectroscopy of Superfluid 3He in Aerogel  

SciTech Connect

We have designed an experiment to study the role of global anisotropic quasiparticle scattering on the dirty aerogel superfluid 3He system. We observe significant regions of two stable phases at temperatures below the superfluid transition at a pressure of 25 bar for a 98% aerogel.

Davis, J. P.; Choi, H.; Pollanen, J.; Halperin, W. P. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)

2006-09-07

370

Cryogenic Testing of Different Seam Concepts for Multilayer Insulation Systems  

NASA Technical Reports Server (NTRS)

Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory has focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was comprised of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5-mm, giving an average layer density of 32 layers per centimeter. The blankets were tested at high vacuum, soft vacuum, and no vacuum using liquid nitrogen to maintain the cold boundary temperature at 77 K. Test results show that all three seam concepts are all close in thermal performance; however the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and re-tested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process.

Johnson, Wesley L.; Fesmire, J. E.

2009-01-01

371

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

372

Deformation of silica aerogels during adsorption of helium and neon  

NASA Astrophysics Data System (ADS)

Fluids confined in aerogel, especially ^3He and ^4He, have been intensely studied for over a decade. Because of the low surface tensions of these fluids, capillary forces are small and the resulting deformation of the aerogel is usually neglected. However, high porosity aerogels are very compressible and large volume changes have been seen^1 during adsorption of nitrogen, which has a much higher surface tension. We have used a linear variable differential transformer (LVDT) to measure the deformation of aerogels as fluids capillary condense within them. Our measurements are taken along isotherms near the critical points of neon and helium and show small volume changes in the aerogel during adsorption and desorption. 1. G. Reichenauer and G.W. Scherer, J. Non-Cryst. Solids 277 (2000) 162.

Herman, Tobias; Beamish, John

2004-03-01

373

An easy way to prepare monolithic inorganic oxide aerogels.  

PubMed

Inorganic oxide aerogels have unique thermal, optical, electrical, magnetic, and chemical properties, which result in them potentially having a broad range of applications. However, their preparation is commonly based on a supercritical drying method, which greatly limits real applications of aerogels and their commercialization. Here we demonstrate a general method for drying wet gels to form aerogels that is based on the sublimation of organic solvent. The organic solvent must have a low surface tension, undergo sublimation easily, and have a high freezing point to allow the rapid synthesis of monolithic inorganic oxide aerogels under vacuum conditions. This cost-effective process will facilitate application of aerogel materials. This approach may also be used for the preparation of other porous materials, whose theoretical and practical applications should be investigated. PMID:25056911

Ren, Lili; Cui, Sumin; Cao, Fengchao; Guo, Qinghui

2014-09-15

374

Method for preparing a solid phase microextraction device using aerogel  

DOEpatents

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

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

2006-10-24

375

Synthesis and Characterization of a Nanocrystalline Thoria Aerogel  

SciTech Connect

We report the synthesis and characterization for the first example of a low-density nanocrystalline thoria aerogel. The monolithic aerogels were prepared through the solgel polymerization of hydrated thorium nitrate in ethanol using ammonium hydroxide and propylene oxide as gelation initiators. The dried ThO{sub 2} aerogel was characterized by high-resolution transmission electron microscopy (HRTEM) and nitrogen adsorption/desorption analyses. The aerogel network was determined to be composed of spherical primary particles with features in the 5-20 nm range. These particles were also determined to be highly crystalline as evidenced by the higher magnification TEM examination. The thoria aerogel possesses high surface area (120 m{sup 2}/g) and pore diameters in the micro- and mesoporous range.

Reibold, R A; Satcher, Jr, J H; Baumann, T F; Simpson, R L; Poco, J F

2004-02-04

376

Comparison of thermal insulation performance of fibrous materials for the advanced space suit.  

PubMed

The current multi-layer insulation used in the extravehicular mobility unit (EMU) will not be effective in the atmosphere of Mars due to the presence of interstitial gases. Alternative thermal insulation means have been subjected to preliminary evaluation by NASA to attempt to identify a material that will meet the target conductivity of 0.005 W/m-K. This study analyzes numerically the thermal conductivity performance for three of these candidate insulating fiber materials in terms of various denier (size), interstitial void fractions, interstitial void media, and orientations to the applied temperature gradient to evaluate their applicability for the new Mars suit insulation. The results demonstrate that the best conductive insulation is achieved for a high-void-fraction configuration with a grooved fiber cross section, aerogel void medium, and the fibers oriented normal to the heat flux vector. However, this configuration still exceeds the target thermal conductivity by a factor of 1.5. PMID:14618923

Paul, Heather L; Diller, Kenneth R

2003-10-01

377

Composite ceria-coated aerogels and methods of making the same  

DOEpatents

Ceria-coated aerogels can include an aerogel support material having a stabilized ceria coating thereon. The ceria coating can be formed by solution or vapor deposition of alcogels or aerogels. Additional catalytic metal species can also be incorporated into the coating to form multi-metallic compounds having improved catalytic activity. Further, the ceria coated aerogels retain high surface areas at elevated temperatures. Thus, improvements in catalytic activity and thermal stability can be achieved using these ceria-coated composite aerogels.

Eyring, Edward M; Ernst, Richard D; Turpin, Gregory C; Dunn, Brian C

2013-05-07

378

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

Microsoft Academic Search

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

Andrew J. Westphal; Christopher J. Snead; Anna L. Butterworth; Giles A. Graham; John P. Bradley; Saÿsa Bajt; Patrick G. Grant; Graham Bench; Sean Brennan; P Piannetta

2003-01-01

379

Aerogel keystones: Extraction of complete hypervelocity impact events from aerogel collectors  

Microsoft Academic Search

In January 2006, the Stardust mission will return the first samples from a solid solar system body beyond the Moon 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

Andrew J. Westphal; Christopher Snead; Anna Butterworth; Giles A. Graham; John P. Bradley; Sasa Bajt; Patrick G. Grant; Graham Bench; Sean Brennan; Piero Pianetta

2004-01-01

380

Chemical and morphological effects on the electrochemical properties of carbon aerogels and ruthenium dioxide/carbon aerogel nanocomposites  

NASA Astrophysics Data System (ADS)

The development of high performance electrode materials for electrochemical capacitors has been an active area of research over the past ten years due to the demand for high power portable energy storage devices. One class of material which has shown promising capacitive characteristics in aqueous electrolytes is carbon aerogels. These unique materials exhibit low resistivity, high surface area, and a controllable open microstructure. In this work, the interrelationships between the electrochemical characteristics of the carbon aerogel materials in sulfuric acid electrolytes and the chemical and physical nature of the aerogels have been identified. Specifically, this study examines the influence of surface chemistry and microstructure on the voltammetric response of the carbon aerogel electrodes. Carbon aerogels exhibit a specific capacitance greater than 80 F/g in 1.0 M Hsb2SOsb4. This value is is dependent upon the specific surface area of each sample but is relatively independent of the bulk density of the aerogel. The density of the material does, however, influence the charging time of the electrode due to distributed capacitance effects. The surface of the carbon aerogels can be electrochemically activated to supplement the double-layer charging of the surface with a pseudocapacitive charge storage mechanism at redox-active surface functionalities. A second aspect of this work addresses improving the capacitance of the carbon aerogel materials by chemically modifying the surface of the aerogels. Hydrous ruthenium dioxide, which has shown exceptional pseudocapacitance ({>} 750\\ F/g)sp3, was deposited onto the surface of the carbon aerogel materials by two approaches: chemical vapor impregnation and electrodeposition. Ruthenium metal loadings of greater than 50 wt.% could be achieved using chemical vapor impregnation. Transmission electron microscopy revealed 20A metal particles uniformly distributed on the large interior surface of the aerogels. These modified carbon aerogels exhibit capacitances as high as 250 F/g in sulfuric acid. The electrodeposition and oxidation of hydrous ruthenium dioxide onto non-porous polycrystalline graphite demonstrates the feasibility of this modification technique for increasing the capacitance of the carbon/electrolyte interface. When applied to carbon aerogels, however, the tortuous nature of the aerogel structure limits the practicality of this approach.

Miller, John Martin

381

Fabrication of hydrophobic, electrically conductive and flame-resistant carbon aerogels by pyrolysis of regenerated cellulose aerogels.  

PubMed

In this paper, we reported miscellaneous carbon aerogels prepared by pyrolysis of regenerated cellulose aerogels that were fabricated by dissolution in a mild NaOH/PEG solution, freeze-thaw treatment, regeneration, and freeze drying. The as-prepared carbon aerogels were subsequently characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen adsorption measurements, X-ray diffraction (XRD), Raman spectroscopy, and water contact angle (WCA) tests. The results showed that the carbon aerogels with pore diameters of 1-60 nm maintained interconnected three-dimensional (3D) network after the pyrolysis, and showed type-IV adsorption isotherm. The pyrolysis process leaded to the decomposition of oxygen-containing functional groups, the destruction of cellulose crystalline structure, and the formation of highly disordered amorphous graphite. Moreover, the carbon aerogels also had strong hydrophobicity, electrical conductivity and flame retardance, which held great potential in the fields of waterproof, electronic devices and fireproofing. PMID:25542115

Wan, Caichao; Lu, Yun; Jiao, Yue; Jin, Chunde; Sun, Qingfeng; Li, Jian

2015-03-15

382

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

383

Insulators for high voltages  

Microsoft Academic Search

This book describes electrical insulators for high voltage applications. Topics considered include the insulating materials, the manufacture of wet process porcelain, the manufacture of tempered glass, the glass-fibre core, the polymeric housing, the common problem - terminating an insulator, mechanical constraints, the physics of pollution flashover, the physics of contamination, testing of insulators, conclusions from testing, remedies for flashover, insulators

Looms; J. S. T

1987-01-01

384

Multilayer insulation (MLI) in the Superconducting Super Collider: A practical engineering approach to physical parameters governing MLI thermal performance  

SciTech Connect

Multilayer insulation (MLI) is employed in cryogenic devices to control the heat load of those devices. The physics defining the thermal performance of an MLI system is extremely complex due to the thermal dynamics of numerous interdependent parameters which in themselves contribute differently depending on whether boundary conditions are transient or steady-state. The Multilayer Insulation 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 blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator. Each blanket will be nearly 56 feet long by 6 feet wide and will consist of as many as 32 reflective and 31 spacer layers of material. Discussed are MLI material choices, and the physical parameters which contribute to the operational performance of MLI systems. Disclosed is a method for fabricating MLI blankets by employing a large diameter winding mandrel having a circumference sufficient for the required blanket length. The blanket fabrication method assures consistency in mass produced MLI blankets by providing positive control of the dimensional parameters which contribute to the MLI blanket thermal performance. The fabrication method can be used to mass produce prefabricated MLI blankets that by virtue of the product 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. 9 refs., 4 figs., 2 tabs.

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

1989-03-01

385

Conversion of a room temperature NaK loop to a high temperature MHD facility for Li/V blanket testing  

SciTech Connect

The Vanadium/Lithium system has been the recent focus of ANL`s Blanket Technology Program, and for the last several years, ANL`s Liquid Metal Blanket activities have been carried out in direct support of the ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the development of insulator coatings. Design calculations, Hua and Gohar, show that an electrically insulating layer is necessary to maintain an acceptably low magnetohydrodynamic (MHD) pressure drop in the current ITER design. Consequently, the decision was made to convert Argonne`s Liquid Metal EXperiment (ALEX) from a 200{degree}C NaK facility to a 350{degree}C lithium facility. The upgraded facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups at Hartmann numbers (M) and interaction parameters (N) in the range of 10{sup 3} to 10{sup 5} in lithium at 350{degree}C. Following completion of the upgrade work, a short performance test was conducted, followed by two longer, multiple-hour, MHD tests, all at 230{degree}C. The modified ALEX facility performed up to expectations in the testing. MHD pressure drop and test section voltage distributions were collected at Hartmann numbers of 1000. 4 refs., 2 figs.

Reed, C.B.; Haglund, R.C.; Miller, M.E.; Nasiatka, J.R. [Argonne National Lab., IL (United States); Kirillov, I.R.; Ogorodnikov, A.P.; Preslitski, G.V.; Goloubovitch, G.P. [D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Xu, Z.Y.

1996-12-31

386

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

SciTech Connect

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

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

1988-03-01

387

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

388

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

389

Thermally distinct ejecta blankets from Martian craters  

NASA Astrophysics Data System (ADS)

A study of Martian ejecta blankets is carried out using the high-resolution thermal IR/visible data from the Termoskan instrument aboard Phobos '88 mission. It is found that approximately 100 craters within the Termoskan data have an ejecta blanket distinct in the thermal infrared (EDITH). These features are examined by (1) a systematic examination of all Termoskan data using high-resolution image processing; (2) a study of the systematics of the data by compiling and analyzing a data base consisting of geographic, geologic, and mormphologic parameters for a significant fraction of the EDITH and nearby non-EDITH; and (3) qualitative and quantitative analyses of localized regions of interest. It is noted that thermally distinct ejecta blankets are excellent locations for future landers and remote sensing because of relatively dust-free surface exposures of material excavated from depth.

Betts, B. H.; Murray, B. C.

1993-06-01

390

Intermetallic and Electrical Insulator Coatings on High Temperature Alloys, Properties in Liquid-Lithium Environments  

Microsoft Academic Search

In the design of liquid-metal cooling systems for fusion-reactor blanket applications, the corrosion resistance of structural materials and the magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. When the system is cooled by liquid metals, insulator coatings are required on piping surfaces in contact with the coolant. The objective of this study is

J. H. Park; W. D. Cho

1995-01-01

391

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

392

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

2011-01-18

393

The AMS-01 Aerogel Threshold Cherenkov counter  

E-print Network

The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 degrees orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate antiprotons from electrons and positrons from protons, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

D. Barancourt; F. Barao; G. Barbier; G. Barreira; M. Buenerd; G. Castellini; E. Choumilov; J. Favier; N. Fouque; A. Gougas; V. Hermel; R. Kossakowski; G. Laborie; G. Laurenti; S. -C. Lee; F. Mayet; B. Meillon; Y. -T. Oyang; V. Plyaskin; V. Pojidaev; C. Rossin; D. Santos; F. Vezzu; J. P. Vialle

2000-10-12

394

Synthesis and properties of Chitosan-silica hybrid aerogels  

SciTech Connect

Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.

Ayers, Michael R.; Hunt, Arlon J.

2001-06-01

395

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

396

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

397

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

398

Tank Insulation  

NASA Technical Reports Server (NTRS)

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

1979-01-01

399

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

400

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

401

Thermal conductance and wettability of xenon on resorcinol-formaldehyde aerogels  

NASA Astrophysics Data System (ADS)

We have performed thermal conductivity and adsorption isotherm measurements to investigate the system formed by Xe adsorbed on resorcinol-formaldehyde (RF) aerogel. Below 80 K, the thermal conductivity of the Xe/RF-aerogel system is essentially identical to that of the bare RF aerogel; however, above this temperature the thermal conductivity of the system increases significantly above that of the bare aerogel. Adsorption isotherm measurements indicate that Xe incompletely wets the RF aerogel below Xe's bulk triple point temperature. The thickness of the Xe film that forms on the RF aerogel decreases with decreasing temperature. By 80 K the total amount of Xe present on the aerogel in equilibrium with the saturated vapor pressure is less than the amount needed to form about 1.5 atomic layers of Xe on the substrate. We attribute the observed changes in the thermal conductivity of the Xe/aerogel system to changes in the wettability of the aerogel by the Xe film.

Zhu, Da-Ming; Zambano, Antonio; Migone, Aldo; Harrington, Steven

2001-01-01

402

Acoustic properties of superfluid 3He in 97% aerogel  

NASA Astrophysics Data System (ADS)

Superfluid 3He in silica aerogel provides a unique system for studying the effect of quenched disorder in the unconventional superfluid. We have performed longitudinal ultrasound (5.7 MHz) attenuation and sound velocity measurements of the superfluid 3He in 97% porosity aerogel. The attenuation and sound velocity were determined by direct propagation of sound pulses through the medium in a wide range of temperatures, down to 400 ?K. The superfluid transition, marked by the increase in sound velocity, is substantially suppressed from that in 98% aerogel used in most of studies. The superfluid fraction determined from the sound velocity is less than 0.02 even at the lowest temperature.

Tsujii, H.; Mihara, S.; Abe, S.; Suzuki, H.; Matsumoto, K.

2009-02-01

403

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

404

Anisotropic Phases of Superfluid 3He in Compressed Aerogel  

NASA Astrophysics Data System (ADS)

It has been shown that the relative stabilities of various superfluid states of 3He can be influenced by anisotropy in a silica aerogel framework. We prepared a suite of aerogel samples compressed up to 30% for which we performed pulsed NMR on 3He imbibed within the aerogel. We identified A and B phases and determined their magnetic field-temperature phase diagrams as a function of strain. From these results, we infer that the B phase is distorted by negative strain forming an anisotropic superfluid state more stable than the A phase.

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

2015-03-01

405

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

406

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

407

Anisotropic phases of superfluid ^{3}he in compressed aerogel.  

PubMed

It has been shown that the relative stabilities of various superfluid states of ^{3}He can be influenced by anisotropy in a silica aerogel framework. We prepared a suite of aerogel samples compressed up to 30% for which we performed pulsed NMR on ^{3}He imbibed within the aerogel. We identified A and B phases and determined their magnetic field-temperature phase diagrams as a function of strain. From these results, we infer that the B phase is distorted by negative strain forming an anisotropic superfluid state more stable than the A phase. PMID:25815941

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

2015-03-13

408

Insulation Coordination for Gas Insulated Substations  

Microsoft Academic Search

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

Helfried Anderl; Charles Wagner; Thomas Dodds

1973-01-01

409

Insulation Testing Using Cryostat Apparatus with Sleeve  

NASA Technical Reports Server (NTRS)

The method and equipment of testing continuously rolled insulation materials is presented in this paper. Testing of blanket and molded products is also facilitated. Materials are installed around a cylindrical copper sleeve using a wrapping machine. The sleeve is slid onto the vertical cold mass of the cryostat. The gap between the cold mass and the sleeve measures less than 1 mm. The cryostat apparatus is a liquid nitrogen boiloff calorimeter system that enables direct measurement of the apparent thermal conductivity (k-value) of the insulation system at any vacuum level between 5 x 10(exp -5) and 760 torr. Sensors are placed between layers of the insulation to provide complete temperature-thickness profiles. The temperatures of the cold mass (maintained at 77.8 kelvin (K)), the sleeve (cold boundary temperature (CBT)), the insulation outer surface (warm boundary temperature (WBT)), and the vacuum can (maintained at 313 K by a thermal shroud) are measured. Plots of CBT, WBT, and layer temperature profiles as functions of vacuum level show the transitions between the three dominant heat transfer modes. For this cryostat apparatus, the measureable heat gain is from 0.2 to 20 watts. The steady-state measurement of k-value is made when all temperatures and the boiloff rate are stable.

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

1999-01-01

410

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

411

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

412

Method for net-shaping using aerogels  

DOEpatents

A method of net-shaping using aerogel materials is provided by first forming a sol, aging the sol to form a gel, with the gel having a fluid component and having been formed into a medium selected from the group consisting of a powder, bulk material, or granular aerobeads, derivatizing the surface of the gel to render the surface unreactive toward further condensation, removing a portion of the fluid component of the final shaped gel to form a partially dried medium, placing the medium into a cavity, wherein the volume of said medium is less that the volume of the cavity, and removing a portion of the fluid component of the medium. The removal, such as by heating at a temperature of approximately less than 50.degree. C., applying a vacuum, or both, causes the volume of the medium to increase and to form a solid aerogel. The material can be easily removed by exposing the material to a solvent, thereby reducing the volume of the material. In another embodiment, the gel is derivatized and then formed into a shaped medium, where subsequent drying reduces the volume of the shaped medium, forming a net-shaping material. Upon further drying, the material increases in volume to fill a cavity. The present invention is both a method of net-shaping and the material produced by the method.

Brinker, C. Jeffrey (Albuquerque, NM); Ashey, Carol S. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM); Sriram, Chunangad S. (Indianapolis, IN); Harris, Thomas M. (Tulsa, OK)

2001-01-01

413

Multiscale Computer Simulation of Failure in Aerogels  

NASA Technical Reports Server (NTRS)

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

Good, Brian S.

2008-01-01

414

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

2014-11-12

415

Temperature measurements of shocked silica aerogel foam.  

PubMed

We present recent results of equation-of-state (EOS) measurements of shocked silica (SiO_{2}) 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. PMID:25314547

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

416

BLANKET STUDENT ACCIDENT AND SICKNESS INSURANCE  

E-print Network

BLANKET STUDENT ACCIDENT AND SICKNESS INSURANCE Especially Designed for Students of your resources and benefits under the plan of insurance sponsored by your school. It is not a contract of insurance. Your coverage is governed by a policy of student accident and sickness insurance underwritten

Suzuki, Masatsugu

417

BLANKET STUDENT ACCIDENT AND SICKNESS INSURANCE  

E-print Network

BLANKET STUDENT ACCIDENT AND SICKNESS INSURANCE Especially Designed for the Dependents Abroad. This brochure is a summary of your benefits under the plan of insurance sponsored by your school. It is not a contract of insurance. Your coverage is governed by a policy of student accident and sickness insurance

Suzuki, Masatsugu

418

Optimization of beryllium for fusion blanket applications  

SciTech Connect

The primary function of beryllium in a fusion reactor blanket is neutron multiplication to enhance tritium breeding. However, because heat, tritium and helium will be generated in and/or transported through beryllium and because the beryllium is in contact with other blanket materials, the thermal, mechanical, tritium/helium and compatibility properties of beryllium are important in blanket design. In particular, tritium retention during normal operation and release during overheating events are safety concerns. Accommodating beryllium thermal expansion and helium-induced swelling are important issues in ensuring adequate lifetime of the structural components adjacent to the beryllium. Likewise, chemical/metallurgical interactions between beryllium and structural components need to be considered in lifetime analysis. Under accident conditions the chemical interaction between beryllium and coolant and breeding materials may also become important. The performance of beryllium in fusion blanket applications depends on fabrication variables and operational parameters. First the properties database is reviewed to determine the state of knowledge of beryllium performance as a function of these variables. Several design calculations are then performed to indicate ranges of fabrication and operation variables that lead to optimum beryllium performance. Finally, areas for database expansion and improvement are highlighted based on the properties survey and the design sensitivity studies.

Billone, M.C. [Argonne National Lab., IL (United States). Fusion Power Program

1993-12-31

419

The climatic impact of supervolcanic ash blankets  

NASA Astrophysics Data System (ADS)

Supervolcanoes are large caldera systems that can expel vast quantities of ash, volcanic gases in a single eruption, far larger than any recorded in recent history. These super-eruptions have been suggested as possible catalysts for long-term climate change and may be responsible for bottlenecks in human and animal populations. Here, we consider the previously neglected climatic effects of a continent-sized ash deposit with a high albedo and show that a decadal climate forcing is expected. We use a coupled atmosphere-ocean General Circulation Model (GCM) to simulate the effect of an ash blanket from Yellowstone volcano, USA, covering much of North America. Reflectivity measurements of dry volcanic ash show albedo values as high as snow, implying that the effects of an ash blanket would be severe. The modeling results indicate major disturbances to the climate, particularly to oscillatory patterns such as the El Niño Southern Oscillation (ENSO). Atmospheric disruptions would continue for decades after the eruption due to extended ash blanket longevity. The climatic response to an ash blanket is not significant enough to instigate a change to stadial periods at present day boundary conditions, though this is one of several impacts associated with a super-eruption which may induce long-term climatic change.

Jones, Morgan T.; Sparks, R. Stephen J.; Valdes, Paul J.

2007-11-01

420

Superfluid transition in superfluid 3He in radially compressed aerogel  

NASA Astrophysics Data System (ADS)

The Spin Supercurrent and Bose-Einstein condensation of magnons similar to an atomic BEC was observed in 1984 in superfluid 3He-B Recently we discovered 2 new types of BEC in superfluid 3He in deformed aerogel. The orbital part of the wave function orients along the deformation and changes the magnon-magnon interaction. We can do it for 3He-A by uniaxially compressing the aerogel along the magnetic field. The other BEC state was observed in 3He-B in aerogel stretched along the magnetic field. Both states show all properties of magnon BEC We have also observed a splitting of NMR lines near Tc, which seems to indicate the formation of a new phase of superfluid 3He in aerogel. The latter looks like an analog of the 3He-A1 phase with strongly enhanced magnetic field.

Hunger, P.; Bunkov, Yu M.; Collin, E.; Godfrin, H.

2012-12-01

421

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

422

Graphene nanoribbon aerogels unzipped from carbon nanotube sponges.  

PubMed

Graphene nanoribbon aerogels are fabricated by directly unzipping multi-walled carbon nanotube sponges. These fascinating materials have potential applications as high performance nanocomposites and supercapacitor electrodes. PMID:24496883

Peng, Qingyu; Li, Yibin; He, Xiaodong; Gui, Xuchun; Shang, Yuanyuan; Wang, Chunhui; Wang, Chao; Zhao, Wenqi; Du, Shanyi; Shi, Enzheng; Li, Peixu; Wu, Dehai; Cao, Anyuan

2014-05-28

423

Preparation of bulk sodium carboxymethyl cellulose aerogels with tunable morphology.  

PubMed

Homogeneous and bulk carboxymethyl cellulose hydrogel and aerogel were prepared by a novel process, using Fe(3+) and d-(+)-gluconic acid-lactone as cross-linker and releasing agent, respectively. The results showed that the mass fraction of Fe(3+) has a great effect on CMC aerogels' structure, crystallization and morphology. By adjusting the mass fraction of Fe(3+), granular, three-dimensional network and rod-like morphology were obtained, responding to varying density and porosity. The aerogel had low density (low to 0.0568 g/cm(3)) and high porosity (up to 90.45%). Meantime. Combination patterns between carboxylate ion and iron ion were checked by FTIR. Furthermore, with the addition of Fe(3+), lattice mismatch of CMC emerged and led to decreasing crystalline degree and thermal stability. This work would play an important role in the handy and extensive application of CMC aerogels. PMID:25542117

Lin, Runjun; Li, Ang; Lu, Lingbin; Cao, Yang

2015-03-15

424

Tests of a proximity focusing RICH with aerogel as radiator  

E-print Network

Using aerogel as radiator and multianode PMTs for photon detection, a proximity focusing Cherenkov ring imaging detector has been constructed and tested in the KEK $\\pi$2 beam. The aim is to experimentally study the basic parameters such as resolution of the single photon Cherenkov angle and number of detected photons per ring. The resolution obtained is well approximated by estimates of contributions from pixel size and emission point uncertainty. The number of detected photons per Cherenkov ring is in good agreement with estimates based on aerogel and detector characteristics. The values obtained turn out to be rather low, mainly due to Rayleigh scattering and to the relatively large dead space between the photocathodes. A light collection system or a higher fraction of the photomultiplier active area, together with better quality aerogels are expected to improve the situation. The reduction of Cherenkov yield, for charged particle impact in the vicinity of the aerogel tile side wall, has also been measured.

I. Adachi; I. Bizjak; A. Gorisek; T. Iijima; M. Iwamoto; S. Korpar; P. Krizan; R. Pestotnik; M. Staric; A. Stanovnik; T. Sumiyoshi; K. Suzuki; T. Tabata

2003-03-25

425

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

426

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

427

Water-cooled solid-breeder blanket concept for ITER  

SciTech Connect

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

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

1989-03-01

428

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

429

Multiple density layered insulator  

DOEpatents

A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

Alger, Terry W. (Tracy, CA)

1994-01-01

430

Insulation Materials Investigation  

NSDL National Science Digital Library

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

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

431

Multiple density layered insulator  

DOEpatents

A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

Alger, T.W.

1994-09-06

432

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

433

Titanium oxide aerogels prepared from titanium metal and hydrogen peroxide  

Microsoft Academic Search

The reaction of hydrogen peroxide with excess titanium metal produces rigid titanium oxide aquagels. Subsequent solvent exchanges with ethanol and carbon dioxide, and supercritical drying produces the corresponding aerogels. The aerogels are translucent yellow in appearance, are amorphous to X-rays, and have a BET surface area of 350 m2\\/g. The empirical formula of the material, as prepared, is TiO3H2.7C0.35. Infrared

M. R Ayers; A. J Hunt

1998-01-01

434

AEM and HREM evaluation of carbon nanostructures in silica aerogels  

SciTech Connect

Nanostructured carbon has been deposited in silica aerogels by chemical vapor infiltration using acetylene or ferrocene at moderate temperatures. Using analytical electron microscopy and high-resolution electron microscopy, we have observed various carbon rings and nanotubes in the silica aerogel-based carbon composite. Both X-ray microanalysis and nano-probe diffraction techniques have been used to confirm the presence of those carbon nanostructures. Morphologies and structural properties of the carbon nanotubes and rings have also been examined in detail.

Song, X.Y.; Cao, W.; Hunt, A.J.

1994-04-01

435

Models for Superfluid H3e in Aerogel  

Microsoft Academic Search

Several recent experiments find evidence of superfluidity of 3He in\\u000a98%-porous aerogel. The primary effect of the aerogel is that it scatters the\\u000aquasiparticles of 3He. We find that many experimental findings are\\u000aquantitatively understood by a relatively simple model that takes into account\\u000astrong inhomogeneity of the scattering on a length scale of 100 nm.

E. V. Thuneberg; S. K. Yip; M. Fogelstrom; J. A. Sauls

1998-01-01

436

Morphology and electrochemistry of ruthenium\\/carbon aerogel nanostructures  

Microsoft Academic Search

The structure-property relationships of nanostructured Ru\\/carbon aerogel composite materials have been evaluated. These new materials were prepared via a novel two-step metal vapor impregnation method which enables one to control the Ru loading through repetition of the process. The resulting microstructure is characterized by highly dispersed Ru particles (â20--30 â« in diameter) attached to the carbon aerogel surface and distributed

J. M. Miller; B. Dunn

1999-01-01

437

Structure of organic aerogels. 1. Morphology and scaling  

Microsoft Academic Search

Small-angle X-ray scattering is used to determine the structure of nanoporous organic aerogels made by the base-catalyzed polymerization of resorcinol and formaldehyde. This study probes the effect of several variables on the morphology of the supercritically dried aerogels including catalyst concentration, monomer concentration, acid aging, and pyrolysis. In addition, the development of structure during polymerization and aging of the precursor

R. W. Pekala; D. W. Schaefer

1993-01-01

438

New organic aerogels based upon a phenolic-furfural reaction  

Microsoft Academic Search

The aqueous polycondensation of (1) resorcinol with formaldehyde and (2) melamine with formaldehyde are two proven synthetic routes for the formation of organic aerogels. A new type of organic aerogel based upon a phenolic-furfural (PF) reaction was recently discovered. This sol?gel polymerization has a major advantage over past approaches since it can be conducted in alcohol (e.g., 1-propanol), thereby eliminating

R. W Pekala; C. T Alviso; X Lu; J Gross; J Fricke

1995-01-01

439

Impact Features and Projectile Residues in Aerogel Exposed on Mir  

Microsoft Academic Search

Approximately 0.63 m2 of SiO2-based aerogel (0.02 g cm?3) was exposed for 18 months on the Mir Station to capture hypervelocity particles from both man-made and natural sources. Optical inspection revealed two major classes of hypervelocity impact features in the aerogel: (1) long, carrot-shaped tracks, well known from laboratory impact experiments, that exhibit a depth- (t) to-diameter (D) relationship of

F. Hörz; M. E. Zolensky; R. P. Bernhard; T. H. See; J. L. Warren

2000-01-01

440

A RICH with aerogel: a study of refractive index uniformity  

E-print Network

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

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

2004-01-01

441

Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel  

SciTech Connect

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

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

2009-01-22

442

Hydrodynamic Property of Oscillating Superfluid 3He in Aerogel  

SciTech Connect

The investigation of the superfluidity of liquid 3He in aerogel of 97.5% and 98.5% porosities using the fourth sound resonance technique revealed two distinct observations. First, the superfluid transition temperature TC and the superfluid density {rho}s/{rho} of 3He in aerogel are greatly suppressed. Second, the sound attenuation does not depend on temperature at higher temperatures, but monotonically diminishes with decreasing temperature at lower temperatures.

Obara, K.; Nago, Y.; Yano, H.; Ishikawa, O.; Hata, T. [Graduate School of Science, Osaka City University, Osaka 558-8585 (Japan); Yokogawa, H.; Yokoyama, M. [Advanced Technology Research Laboratory, Matsushita Electric Works, Ltd. (Japan)

2006-09-07

443

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

444

Imbibition of Liquid Helium in Aerogels  

NASA Astrophysics Data System (ADS)

We report optical measurements of the imbibition of liquid helium in a sample of silica aerogel with 90 % porosity. Both direct imaging and light scattering experiments were performed to determine the dynamics and the properties of the liquid-gas interface in both the normal and superfluid phases of liquid helium. In the normal phase, a classical Lucas Washburn behavior is observed for the rise of the imbibition front while the behavior in the superfluid phase is markedly different, as the fluid invades the sample from all sides with a constant speed. In both phases, the interface is rough, leading to light scattering. In addition, condensation ahead of the imbibition front is observed at low temperature in the superfluid phase.

Spathis, P.; Delga, A.; Malheiro, C.; Wolf, P. E.

2013-06-01

445

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

446

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 Collin; Stadermann, Michael

2014-07-15

447

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

448

Silica Aerogel for Use in Cosmic Dust Collectors Utilized in the Tanpopo Mission  

NASA Astrophysics Data System (ADS)

We are developing silica aerogels for use in cosmic dust collectors utilized in the Tanpopo mission. In this paper, we present the recent development of a box-framing aerogel in contamination-controlled environments.

Tabata, M.; Yano, H.; Kawai, H.; Imai, E.; Hashimoto, H.; Yokobori, S.; Yamagishi, A.; Tanpopo Working Group

2013-11-01

449

Preparation and characterization of silica aerogels from diatomite via ambient pressure drying  

NASA Astrophysics Data System (ADS)

The silica aerogels were successfully fabricated under ambient pressure from diatomite. The influence of different dilution ratios of diatomite filtrate on physical properties of aerogels were studied. The microstructure, surface functional groups, thermal stability, morphology and mechanical properties of silica aerogels based on diatomite were investigated by BET adsorption, FT-IR, DTA-TG, FESEM, TEM, and nanoindentation methods. The results indicate that the filtrate diluted with distilled water in a proportion of 1: 2 could give silica aerogels in the largest size with highest transparency. The obtained aerogels with density of 0.122-0.203 g/m3 and specific surface area of 655.5-790.7 m2/g are crack free amorphous solids and exhibited a sponge-like structure. Moreover, the peak pore size resided at 9 nm. The initial aerogels were hydrophobic, when being heat-treated around 400°C, the aerogels were transformed into hydrophilic ones. The obtained aerogel has good mechanical properties.

Wang, Baomin; Ma, Hainan; Song, Kai

2014-07-01

450

Thermal conductance and wettability of Xe on resorcinol-formaldehyde aerogels  

NASA Astrophysics Data System (ADS)

We have performed thermal conductivity and adsorption isotherm measurements to investigate Xe adsorbed on resorcinol-formaldehyde (RF) aerogel. Below 80 K, the thermal conductivity of the Xe/RF-aerogel system is essentially identical to that of the bare RF-aerogel. Above this temperature the thermal conductivity of the system increases significantly above that of the bare aerogel. Adsorption isotherm measurements indicate that Xe incompletely wets the RF-aerogel below Xe’s bulk triple point temperature. The maximum amount of Xe adsorbed on the RF-aerogel at the bulk saturation pressure decreases with temperature. By 80 K the total amount of Xe present on the aerogel in equilibrium with the saturated vapor pressure is less than the amount needed to form about 1.5 atomic layers of Xe on the substrate. The observed changes in the thermal conductance can be understood in terms of decreasing wettability of Xe on the RF-aerogel as temperature decreases.

Zhu, Da-Ming; Zambano, Antonio; Migone, Aldo; Harrington, Steven; Rao, Nanxia

2001-03-01

451

Cover times, blanket times, and majorizing measures  

E-print Network

We exhibit a strong connection between cover times of graphs and Talagrand's theory of majorizing measures. In particular, we show that the cover time of any graph $G$ can be characterized, up to universal constants, by the square of Talagrand's $\\gamma_2$ functional applied to an appropriate metric space on the vertices of $G$. This allows us to resolve a number of open questions. We give a deterministic polynomial-time algorithm that computes the cover time to within an O(1) factor for any graph, answering a question of Aldous and Fill (1994). We also positively resolve the blanket time conjectures of Winkler and Zuckerman (1996), showing that for any graph, the blanket and cover times are within an O(1) factor. The best previous approximation factor for both these problems was $O((\\log \\log n)^2)$ for $n$-vertex graphs, due to Kahn, Kim, Lovasz, and Vu (2000).

Ding, Jian; Peres, Yuval

2010-01-01

452

Thermal insulating capabilities of "thin" clothing insulation.  

PubMed

Claims have been made that certain "thin" polyolefin clothing insulating materials possess superior insulating capabilities because they consist of extremely fine fibers. In a comparative study, swatches of the usual clothing materials, down, polyester, and polyolefin were examined by a technique that allowed two methods of calculating the insulation value, one across the sample and the second from the inner surface of the sample to the ambient air. The second method produces a value that includes the air layer which adheres to all clothing, increasing the apparent insulation. The thermal insulation of the material, per se, does not change. The data demonstrate that the claims can be made for any thin insulation. PMID:4062767

Kaufman, W C; Bothe, D J

1985-10-01

453

Synthesis and characterization of a low-density urania (UO 3) aerogel  

Microsoft Academic Search

We report the synthesis and characterization for the first example of a low-density urania aerogel. The monolithic aerogels were prepared through the sol–gel polymerization of hydrated uranyl nitrate in ethanol using propylene oxide as a gelation initiator. The dried UO3 aerogel was characterized by high-resolution transmission electron microscopy and nitrogen adsorption\\/desorption analyses. The aerogel micro-structure was determined to be composed

Robert A Reibold; John F Poco; Theodore F Baumann; Randall L Simpson; Joe H Satcher

2003-01-01

454

Ceramic helium-cooled blanket test module  

Microsoft Academic Search

The design of RF DEMO-relevant ceramic helium cooled blanket test module (CHC BTM) for testing in international thermonuclear experimental reactor (ITER) is under consideration. The RF concept of DEMO BTM is based upon the breeder inside tube (BIT)-concept. This concept suggests the use of solid breeding ceramic material, helium as coolant and tritium purge-gas, ferrite–martensite steel as structural material, and

A Leshukov; V Kovalenko; G Shatalov; G Goroshkin; A Obukhov

2000-01-01

455

TCT hybrid preconceptual blanket design studies  

SciTech Connect

The conceptual design of a tokamak fusion-fission (hybrid) reactor, which produces electric power and fissile material, has been performed in a cooperative effort between Princeton's Plasma Physics Laboratory (PPPL) and Battelle's Pacific Northwest Laboratories (PNL). PPPL, who had overall project lead responsibility, designed the fusion driver system. Its core consists of a tokamak plasma maintained in the two-component torus (TCT) mode by both D and T beams and having a single null poloidal divertor. The blanket concept selected by PPPL consists of a neutron multiplying converter region, containing natural Uranium Molybdenum (U-Mo) slugs followed by a fuel burning blanket region of molten salt containing PuF/sub 3/. PNL analyzed this concept to determine its structural, thermal and hydraulic performance characteristics. An adequate first wall cooling method was determined, utilizing low pressure water in a double wall design. A conceptual layout of the converter region tubes was performed, providing adequate helium cooling and the desired movement of U-Mo slugs. A thermal hydraulic analysis of the power-producing blanket regions indicated that either more helium coolant tubes are needed or the salt must be circulated to obtain adequate heat removal capability.

Aase, D.T.; Bampton, M.C.C.; Doherty, T.J.; Leonard, B.R.; McCann, R.A.; Newman, D.F.; Perry, R.T.; Stewart, C.W.

1978-01-01

456

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

457

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

458

Size control and characterization of spherical carbon aerogel particles from resorcinol–formaldehyde resin  

Microsoft Academic Search

Spherical resorcinol–formaldehyde (RF) aerogel particles were synthesized by emulsion polymerization of resorcinol with formaldehyde in a slightly basic aqueous solution, followed by supercritical drying with carbon dioxide. RF carbon aerogel particles were prepared by carbonizing of the RF aerogel particles at a high temperature under a nitrogen atmosphere. By changing the viscosity of the RF sol added to the cyclohexane

Toshihide Horikawa; Jun’ichi Hayashi; Katsuhiko Muroyama

2004-01-01