SCAN_23-01

23-01 CHEMICAL ANALYSIS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

23-02 CHEMICAL PROCESSES AND ENGINEERING
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Oxidation of Carbon/Carbon through Coating Cracks
Document ID:
20090004576
Report #:
E-16840
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Jacobson, N. S. (NASA Glenn Research Center) Roth, d. J. (NASA Glenn Research Center) Rauser, R. W. (Toledo Univ.) Cawley, J. D. (Case Western Reserve Univ.) Curry, D. M. (Boeing Co.)
Published:
20081012
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
11
Contract #:
None
Abstract:
Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonab
Language:
English
Notes:
214th Meeting of the Electrochemical Society Honolulu, HI 12-17 Oct. 2008

Title:
Synthesis and Compatibility of Ionic Liquid Containing Rod-Coil Polyimide Gel Electrolytes with Lithium Metal Electrodes
Document ID:
20090004881
Report #:
E-16876
Available Online:
http://dx.doi.org/10.1149/1.2967723
Sales Agency:
Other Sources Copyright
Author(s):
Tigelaar, Dean M. (NASA Glenn Research Center) Palker, Allyson E. (NASA Glenn Research Center) Meador, Mary Ann B. (NASA Glenn Research Center) Bennett, William R. (NASA Glenn Research Center)
Journal:
Journal of Electrochemical Society, Volume: Volume 155 , Issue: Issue 10 , Page: A768-A774
Published:
20080819 Publisher: Electrochemical Society, Inc.
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
7
Contract #:
None
Abstract:
A highly cross-linked polyimide-polyethylene oxide copolymer has been synthesized that is capable of holding large volumes of liquid component, simultaneously maintaining good dimensional stability. An amine end capped oligomer was made that was imidized in solution, followed by reaction with a triisocyanate in the presence of desired additives at ambient temperature. Polymer films are able to hold over 4 times their weight in room temperature ionic liquid RTIL or carbonate solvent. Electrolytes were studied that contained varying amounts of RTIL, lithium trifluoromethanesulfonimide LiTFSi, and alumina nanoparticles. Electrochemical stability of these electrolytes with lithium metal electrodes was studied by galvanic cycling and impedance spectroscopy. Improved cycling stability and decreased interfacial resistance were observed when increasing amounts of RTIL and LiTFSi were added. The addition of small amounts of alumina further decreased interfacial resistance by nearly an order of magnitude. During the course of the study, cycling stability increased from less than 3 to greater than 1000 h at 60 C and 0.25 mA/cm2 current density.
Language:
English

Title:
Noncoincident Validation of Aura MLS Observations using the Langley Research Center Lagrangian Chemistry and Transport Model
Document ID:
20090004900
Report #:
LF99-5090
Sales Agency:
Other Sources Copyright
Author(s):
Considine, D. B. (NASA Langley Research Center) Natarajan, M. (NASA Langley Research Center) Fairlie, T. D. (NASA Langley Research Center) Lingenfelser, G. S. (Science Systems and Applications, Inc.) Pierce, R. B. (NASA Langley Research Center) Froidevaux, L. (Jet Propulsion Lab., California Inst. of Tech.) Lambert, A. (Jet Propulsion Lab., California Inst. of Tech.)
Published:
20080101
Source:
NASA Langley Research Center (Hampton, VA, United States)
Pages:
48
Contract #:
None
Abstract:
We use the Langley Research Center Lagrangian Chemistry and Transport model to evaluate Aura Microwave Limb Sounder observations of O3, HCl, and H2O. The LCTM tracks the dynamical and photochemical evolution of an ensemble of air parcels following initialization from three continuous weeks of version 19 HALOE observations made during November, 2004. We show that the LCTM air parcel predictions agree closely with subsequent late November HALOE measurements not used to initialize the model, demonstrating the model s capability to accurately propagate information from the HALOE observations. We compare version 2.2 MLS observations of O3, HCl, and H2O made on November 29, 2004 with coincident LCTM predictions. We find very good agreement in the stratosphere with MLS O3, with differences generally less than 10%. We find low biases in HCl of 10-30% relative to the MLS observations. We also find low biases with respect to MLS H2O of up to 15% in the upper and mid stratosphere, and up to 50% low biases in the lower stratosphere/upper troposphere midlatitudes. We note nonphysical oscillations of MLS H2O in the tropical and midlatitude lower stratosphere that are not present in the HALOE-initialized LCTM output. The oscillations are smaller in version 2.2 than in previous versions. These results are generally consistent with published HALOE/MLS intercomparisons of these species using a traditional coincident validation technique. This suggests that the traditional coincident validation results are applicable on daily and zonal time and spatial scales.
Language:
English
Notes:
To be published in the Journal of Geophysical Research, volume 113, May 2008

23-03 LUMINESCENCE
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Spray Chemical Vapor Deposition of Single-Source Precursors for Chalcopyrite I-III-VI2 Thin-Film Materials
Document ID:
20090004419
Report #:
NASA/TP-2008-214937, E-16162-1
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Hepp, Aloysius F. (NASA Glenn Research Center) Banger, Kulbinder K. (Ohio Aerospace Inst.) Jin, Michael H.-C. (Texas Univ.) Harris, Jerry D. (Northwest Nazarene Univ.) McNatt, Jeremiah S. (NASA Glenn Research Center) Dickman, John E. (NASA Glenn Research Center)
Published:
20081101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
33
Contract #:
NNC04AA71A NCC3-947
Abstract:
Thin-film solar cells on flexible, lightweight, space-qualified substrates provide an attractive approach to fabricating solar arrays with high mass-specific power. A polycrystalline chalcopyrite absorber layer is among the new generation of photovoltaic device technologies for thin film solar cells. At NASA Glenn Research Center we have focused on the development of new single-source precursors (SSPs) for deposition of semiconducting chalcopyrite materials onto lightweight, flexible substrates. We describe the syntheses and thermal modulation of SSPs via molecular engineering. Copper indium disulfide and related thin-film materials were deposited via aerosol-assisted chemical vapor deposition using SSPs. Processing and post-processing parameters were varied in order to modify morphology, stoichiometry, crystallography, electrical properties, and optical properties to optimize device quality. Growth at atmospheric pressure in a horizontal hotwall reactor at 395 C yielded the best device films. Placing the susceptor closer to the evaporation zone and flowing a more precursor-rich carrier gas through the reactor yielded shinier-, smoother-, and denser-looking films. Growth of (112)-oriented films yielded more Cu-rich films with fewer secondary phases than growth of (204)/(220)-oriented films. Post-deposition sulfur-vapor annealing enhanced stoichiometry and crystallinity of the films. Photoluminescence studies revealed four major emission bands and a broad band associated with deep defects. The highest device efficiency for an aerosol-assisted chemical vapor deposited cell was one percent.
Language:
English
Notes:
Based upon chapter to be published in "Solution-Based Processing of INorganic Films" by Wiley and Sons

Title:
Electroluminescence Efficiency Enhancement using Metal Nanoparticles
Document ID:
20090004479
Report #:
AD-A486769, AFRL-RY-HS-TP-2008-0022
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Soref, Richard A Khurgin, J B Sun, G
Published:
20080622
Source:
Air Force Research Lab. (Hanscom AFB, MA United States)
Pages:
4
Contract #:
None
Abstract:
We apply the "effective mode volume" theory to evaluate enhancement of the electroluminescence efficiency of semiconductor emitters placed in the vicinity of isolated metal nanoparticles and their arrays. Using the example of an InGaN/GaN quantum-well active region positioned in close proximity to Ag nanospheres, we show that while the enhancement due to isolated metal nanoparticles is large, only modest enhancement can be obtained with ordered array of those particles. We further conclude that random assembly of isolated particles holds an advantage over the ordered arrays for light emitting devices of finite area.
Language:
English

Title:
Novel Anthracene Diimide Fluorescent Sensor
Document ID:
20090004680
Report #:
E-16854
Available Online:
http://dx.doi.org/10.1021/cm8024704
Sales Agency:
Other Sources Copyright
Author(s):
Tyson, Daniel S. (Ohio Aerospace Inst.) Carbaugh, Ashley D. (NASA Glenn Research Center) Ilhan, Faysal (Ohio Aerospace Inst.) Santos-Perez, Javier (Ohio Aerospace Inst.) Meador, Michael A. (NASA Glenn Research Center)
Journal:
Chemistry of Materials, Volume: Volume 29 , Page: 6595-6596
Published:
20080101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
3
Contract #:
None
Abstract:
Aromatic imides and diimides have attracted considerable attention in molecular electronics, as fluorescent probes in biological systems, and as sensors for the detection of chemical species. With a few exceptions, these reports have been confined to perylene and naphthalene imides and diimides, in part because of the ready availability of the corresponding anhydride and dianhydride starting materials. We have reported the synthesis of an aniline capped anthryl diimide, 1a and its ability to function as an "on-off" sensor for pH, acid halides, and chemical surrogates for Sarin. In the "off state", fluorescence from 1a is completely quenched by intramolecular excited state charge transfer (CT) from the terminal amines. Reaction of these groups inhibits CT quenching and activates the fluorescence. This approach to chemical species detection is highly sensitive, because it is easy to recognize the "on" and "off" states of the dye. Synthesis of 1a involves the generation of o-xylylenols by photolysis of 2,5-dibenzoyl-p-xylene, 2, and their trapping in situ with 4-nitrophenylmaleimide. Although this approach is fairly straightforward, it is limited in scope because only maleimides, which are photochemically stable, can be used. To address this, we have recently prepared the corresponding anthracene dianhydride, 4, and used it to synthesize triaryl amine-terminated diimide 1b. Herein, we present the synthesis and photophysics of 1 and its potential use as a fluorescent sensor for pH and nitroaromatics and as an indicator in thermochromic materials.
Language:
English

Title:
Fluorescence Imaging and Streamline Visualization of Hypersonic Flow over Rapid Prototype Wind-Tunnel Models
Document ID:
20090004702
Report #:
LF99-5899
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Danehy, Paul M. (NASA Langley Research Center) Alderfer, David W. (NASA Langley Research Center) Inman, Jennifer A. (NASA Langley Research Center) Berger, Karen T. (NASA Langley Research Center) Buck, Gregory M. (NASA Langley Research Center) Schwartz, Richard J. (ATK-Aerospace)
Published:
20080101
Source:
NASA Langley Research Center (Hampton, VA, United States)
Pages:
31
Contract #:
None
Abstract:
Reentry models for use in hypersonic wind tunnel tests were fabricated using a stereolithography apparatus. These models were produced in one day or less, which is a significant time savings compared to the manufacture of ceramic or metal models. The models were tested in the NASA Langley Research Center 31-Inch Mach 10 Air Tunnel. Only a few of the models survived repeated tests in the tunnel, and several failure modes of the models were identified. Planar laser-induced fluorescence (PLIF) of nitric oxide (NO) was used to visualize the flowfields in the wakes of these models. Pure NO was either seeded through tubes plumbed into the model or via a tube attached to the strut holding the model, which provided localized addition of NO into the model s wake through a porous metal cylinder attached to the end of the tube. Models included several 2- inch diameter Inflatable Reentry Vehicle Experiment (IRVE) models and 5-inch diameter Crew Exploration Vehicle (CEV) models. Various model configurations and NO seeding methods were used, including a new streamwise visualization method based on PLIF. Virtual Diagnostics Interface (ViDI) technology, developed at NASA Langley Research Center, was used to visualize the data sets in post processing. The use of calibration "dotcards" was investigated to correct for camera perspective and lens distortions in the PLIF images.
Language:
English
Notes:
To be published in The Journal of Aerospace Engineering, volume 222, no. N5, pp. 637-651, 2008

23-04 PHOTOCHEMISTRY
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

24-01 REINFORCED MATERIALS AND FIBERS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites
Document ID:
20090004580
Report #:
E-16844
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Littell, Justin D. (Akron Univ.) Binienda, Wieslaw K. (Akron Univ.) Arnold, William A. (Akron Univ.) Roberts, Gary d. (NASA Glenn Research Center) Goldberg, Robert K. (NASA Glenn Research Center)
Published:
20081020
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
29
Contract #:
None
Abstract:
In previous work, the ballistic impact resistance of triaxial braided carbon/epoxy composites made with large flat tows (12k and 24k) was examined by impacting 2 X2 X0.125" composite panels with gelatin projectiles. Several high strength, intermediate modulus carbon fibers were used in combination with both untoughened and toughened matrix materials. A wide range of penetration thresholds were measured for the various fiber/matrix combinations. However, there was no clear relationship between the penetration threshold and the properties of the constituents. During some of these experiments high speed cameras were used to view the failure process, and full-field strain measurements were made to determine the strain at the onset of failure. However, these experiments provided only limited insight into the microscopic failure processes responsible for the wide range of impact resistance observed. In order to investigate potential microscopic failure processes in more detail, quasi-static tests were performed in tension, compression, and shear. Full-field strain measurement techniques were used to identify local regions of high strain resulting from microscopic failures. Microscopic failure events near the specimen surface, such as splitting of fiber bundles in surface plies, were easily identified. Subsurface damage, such as fiber fracture or fiber bundle splitting, could be identified by its effect on in-plane surface strains. Subsurface delamination could be detected as an out-of-plane deflection at the surface. Using this data, failure criteria could be established at the fiber tow level for use in analysis. An analytical formulation was developed to allow the microscopic failure criteria to be used in place of macroscopic properties as input to simulations performed using the commercial explicit finite element code, LS-DYNA. The test methods developed to investigate microscopic failure will be presented along with methods for determining local failure criteria that can be used in analysis. Results of simulations performed using LS-DYNA will be presented to illustrate the capabilities and limitations for simulating failure during quasi-static deformation and during ballistic impact of large unit cell size triaxial braid composites.
Language:
English
Notes:
Submitted to CompTest 2008 4th International Confrence on Composites Testing and Model Identification Dayton, OH 20-22 Oct. 2008

Title:
Effects of Temperature and Steam Environment on Fatigue Behavior of Three SIC/SIC Ceramic Matrix Composites
Document ID:
20090004664
Report #:
AD-A487597, AFIT/GAE/ENY/08-S02
Available Online:
http://hdl.handle.net/100.2/ADA487597
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Sharma, Vipul
Published:
20080901
Source:
Air Force Inst. of Tech. (Wright-Patterson AFB, OH United States)
Pages:
229
Contract #:
None
Abstract:
The fatigue behavior of two woven SiC-SiNC ceramic matrix composites (CMCs) was investigated at 1300 deg C in laboratory air and in steam. The first composite (C1) consists of a PIP SiNC matrix reinforced with Sylramic (Syl) fibers woven in a five-harness satin weave fabric and coated with a proprietary dual-layer interface. The second composite (C2) consists of a modified PIP SiNC matrix reinforced with Sylramic-iBN (Syl-iBN) fibers woven in a five-harness satin weave fabric and coated with a proprietary dual-layer interface. The tensile stress-strain behavior was investigated and the tensile properties measured at 1300 deg C. Tension-tension fatigue behavior was studied for fatigue stresses ranging from 100 to 180 MPa at 1300 deg C in air and in steam. The presence of steam caused noticeable degradation in fatigue performance of both composites at 1300?C. The fatigue limit of the composite C1 (based on a run-out condition of 2 x 105 cycles) was 100 MPa (53% UTS at 1300 deg C) in both air and steam. The fatigue limit of the composite C2 was 160 MPa (66% UTS) in air and 140 MPa (58% UTS) in steam. The retained strength and modulus of all specimens that achieved run-out were characterized. Specimens of both composites tested in air retained 100% of their tensile strength, while the specimens of both composites tested in steam retained only about 90% of their tensile strength.
Language:
English

24-02 COMPOSITE MATERIALS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Low-Melt Viscosity Imide Resins for Resin Transfer Molding (RTM)
Document ID:
20090004418
Report #:
None
Sales Agency:
Other Sources No Copyright
Author(s):
Chuang, Kathy C. (NASA Glenn Research Center)
Published:
20080101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
36
Contract #:
None
Abstract:
The use of high temperature polymer matrix composites in aerospace applications has expanded steadily over the past 30 years, due to the increasing demand of replacing metal parts with lightweight composite materials for fuel efficiency and bigger payloads in aircraft and space transportation vehicles. Polyimide/carbon fiber composites, especially, have been regarded as major high temperature matrix materials, based on their outstanding performance in terms of heat resistance, high strength-to-weight ratio and property retention relative to epoxies (177 C/ 350 F) and bismaleimides (232 C/450 F). Traditionally, thermoplastic polyimides were prepared from dianhydrides and diamines in N-methyl-2-pyrrolidinone (NMP) at room temperature to form polyamic acids, which were then imidized at 150 C to yield high molecular weight polyimides. However, the high-boiling solvent NMP (BP = 202 C) is very difficult to remove, often leading to the formation of voids during composite fabrication.
Language:
English
Notes:
Innovations in Materials Manufacturing, Fabrication, and Environmental Safety - a Book in preparation, ed. By Mel Schultz

Title:
Assuring Life in Composite Systems
Document ID:
20090004421
Report #:
NASA/TM-2008-215452, E-16526-1
Available Online:
http://hdl.handle.net/2060/20090004421
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Chamis, Christos c. (NASA Glenn Research Center)
Published:
20081101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
21
Contract #:
None
Abstract:
A computational simulation method is presented to assure life in composite systems by using dynamic buckling of smart composite shells as an example. The combined use of composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right below the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 9% at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load. The uncertainties in the electric field strength and smart material volume fraction have moderate effects and thereby in the assured life of the shell.
Language:
English

25-01 CORROSION
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Modeling of Microstructure Evolution During the Thermomechanical Processing of Titanium Alloys (Preprint)
Document ID:
20090004554
Report #:
AD-A490754, AFRL-RX-WP-TP-2008-4353
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Semiatin, S L Furrer, D U
Published:
20080701
Source:
Air Force Research Lab. (Wright-Patterson AFB, OH United States)
Pages:
73
Contract #:
None
Abstract:
Titanium and titanium alloys are widely used for a variety of aerospace, chemical, marine, and other specialty applications because of their high strength, low density, good ductility, fatigue and corrosion resistance, as well as other properties. Depending on the application, a specific property (or combination of properties) can be obtained through microstructural modification. Microstructure evolution and control in titanium alloys is heavily dependent on the allotropic transformation from a hexagonal-close-packed crystal structure (denoted as alpha phase) found at low temperatures to a body-centered-cubic crystal structure (denoted as beta phase) at high temperatures. For pure titanium, this occurs at 882 deg C. In many titanium alloys, the beta phase is partially stabilized at lower temperatures, and the equilibrium volume fractions of alpha and beta vary with temperature. The temperature at which a specific alloy becomes entirely beta is called the beta transus. The conditions used for hot working and heating/heat treatment are often selected relative to the beta-transus temperature.
Language:
English
Notes:
Paper submitted to the ASM Handbook, v22 - Modeling and Simulation: Processing of Metallic Materials. The original document contains color images. All DTIC reproductions will be in black and white

Title:
Some Expected Characteristics of Lunar Dust: A Geological View Applied to Engineering
Document ID:
20090004878
Report #:
E-16875
Available Online:
http://hdl.handle.net/2060/20090004878
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Street, Kenneth W. (NASA Glenn Research Center) Schrader, Christian M. (BAE Systems) Rickman, Doug (NASA Marshall Space Flight Center)
Published:
20081005
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
20
Contract #:
None
Abstract:
Compared to the Earth the geologic nature of the lunar regolith is quite distinct. Even though similar minerals exist on the Earth and Moon, they may have very different properties due to the absence of chemical modification in the lunar environment. The engineering properties of the lunar regolith reflect aspects of the parent rock and the consequences of hypervelocity meteor bombardment. On scales relevant to machinery and chemical processing for In-Situ Resource Utilization, ISRU (such as water production), the lunar regolith compositional range is much more restricted than terrestrial material. This fact impacts predictions of properties required by design engineers for constructing equipment for lunar use. In this paper two examples will be covered. 1) Abrasion is related to hardness and hardness is a commonly measured property for both minerals and engineering materials. Although different hardness scales are routinely employed for minerals and engineering materials, a significant amount of literature is available relating the two. As one example, we will discuss how to relate hardness to abrasion for the design of lunar equipment. We also indicate how abundant the various mineral phases are and typical size distributions for lunar regolith which will impact abrasive nature. 2) Mineral characteristics that may seem trivial to the non-geologist or material scientist may have significant bearing on ISRU processing technologies. As a second example we discuss the impact of traces of F-, Cl-, and OH-, H2O, CO2, and sulfur species which can radically alter melting points and the corrosive nature of reaction products thereby significantly changing bulk chemistry and associated processing technologies. For many engineering uses, a simulant s fidelity to bulk lunar regolith chemistry may be insufficient. Therefore, simulant users need to engage in continuing dialogue with simulant developers and geoscientists.
Language:
English
Notes:
Geological Society of America Meeting Houston, TX 9 Oct. 2008

25-02 METAL CRYSTALS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Progress Towards III-V Photovoltaics on Flexible Substrates
Document ID:
20090004679
Report #:
E-16853
Sales Agency:
CASI Hardcopy A01 Copyright
Author(s):
McNatt, Jeremiah S. (NASA Glenn Research Center) Pal, AnnaMaria T. (NASA Glenn Research Center) Clark, Eric B. (NASA Glenn Research Center) Sayir, Ali (NASA Glenn Research Center) Raffaelle, Ryne P. (Rochester Inst. of Tech.) Bailey, Christopher G. (Rochester Inst. of Tech.) Hubbard, Seth M. (Rochester Inst. of Tech.) Maurer, William F. (Ohio Aerospace Inst.) Fritzemeier, Les (Wakonda Technologies)
Published:
20080728
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
5
Contract #:
None
Abstract:
Presented here is the recent progress of the NASA Glenn Research Center OMVPE group's efforts in the development of high efficiency thin-film polycrystalline III-V photovoltaics on optimum substrates. By using bulk polycrystalline germanium (Ge) films, devices of high efficiency and low mass will be developed and incorporated onto low-cost flexible substrates. Our progress towards the integration of high efficiency polycrystalline III-V devices and recrystallized Ge films on thin metal foils is discussed.
Language:
English
Notes:
6th International Energy Conversion Engineering Conference (IECEC) Cleveland, OH 28-30 Jul. 2008

25-03 COATINGS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Polymer Materials for Ground Mobile Millimeter-Scale Robotics
Document ID:
20090004556
Report #:
AD-A490766, ARL-TR-4659
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Rudy, Ryan Polcawich, Ronald G Pulskamp, Jeff
Published:
20081201
Source:
Army Research Lab. (Adelphi, MD United States)
Pages:
22
Contract #:
None
Abstract:
This project is closely tied with the ongoing work of visiting Professor Kenn Oldham and the U.S. Army Research Laboratory's (ARL) joint effort on creating highly flexible, large payload capacity joints for a ground mobile millimeter-scale robot. The fabrication process to add parylene coatings to the piezo-microelectromechanical systems (piezoMEMS) actuator process has been characterized using test structures. Scanning electron and optical microscopy of the joint assemblies; analysis of the coating technology for trench fill; process robustness to exposure to solvents and photolithographic processing; and adhesion of parylene to both platinum and lead zirconate titanate (PZT) thin films have been completed on two separate fabrication sequences. Parylene coatings have been successfully applied to both platinum and PZT thin films and the challenges associated with parylene survival with multiple fabrication process steps have been evaluated. Future work will include full release of test structures on the existing wafers in fabrication as well as implementation of process improvements into a fully functional piezoMEMS plus parylene actuator joint.
Language:
English

25-04 ELECTROCHEMISTRY
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

26-01 ALUMINUM
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Laser Processed Protonic Ceramics
Document ID:
20090004440
Report #:
E-16833
Available Online:
http://dx.doi.org/10.1016/j.jeurceramsoc.2008.03.038
Sales Agency:
Other Sources Copyright
Author(s):
Dynys, f. W. (NASA Glenn Research Center) Berger, M. H. (Ecole des Mines de Paris) Sayir, A. (NASA Glenn Research Center)
Journal:
Journal of European Ceramic Society, Volume: Volume 28 , Issue: Issue 12 , Page: 2433-2440
Published:
20080521 Publisher: Elsevier Ltd.
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
8
Contract #:
None
Abstract:
High temperature protonic conductors of SrCe(0.9)Y(0.1)O(3-delta), Sr3Ca(1+x)Nb(2-x)O(9-delta) and BaCe(0.85)Y(0.15)O(3-delta) were fabricated by laser processing. Laser float zone method and pulse laser deposition were used to fabricate dense high temperature protonic ceramic rods and films. Melt growth processing by laser float zone produced textured microstructures with cellular characteristics. Directional solidified SrCe(0.9)Y(0.1)O(3-delta) contained an aluminium rich inter-granular phase, whereas Sr3Ca(1+x)Nb(2-x)O(9-delta) exhibits a cellular microstructure with a decreasing Ca/Nb ratio from the cell center to the cell boundary. A low Ca/Nb ratio is detrimental to proton transport. Nano-domains caused by oxygen cage tilting were observed in both compositions. Sr3Ca(1+x)Nb(2-x)O(9-delta) also exhibits stoichiometric domains with an ordered distribution of Nb(5+) and Ca(2+) cations. These domains were surrounded by non-stoichiometric domains containing a random cation distribution, which preserves the global stoichiometry and charge neutrality. Electrical impedance spectroscopy revealed similar protonic transport to published data for sintered compositions. Crystalline BaCe(0.9)Y(0.1)O(3-delta) films were fabricated on porous substrates at deposition temperatures ranging from 400 to 950 C. Crystalline films 1.10 microns thick were deposited by excimer laser on porous Al2O3 and BaZrO3 substrates. Single-phase BaCe(0.85)Y(0.15)O(3-delta) films with a columnar growth morphology are observed with preferred crystal growth along the [100] or [001] direction. The film electrical conductivity was measured perpendicular to the film growth direction. Impedance measurements show the importance of matching crystal symmetry between substrate and film. High protonic conducting films were achieved by deposition on BaZrO3.
Language:
English

Title:
NIST Standard Reference Materials for Use as Thermometric Fixed Points
Document ID:
20090004528
Report #:
PB2008-105968
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Strouse, G. F. Furukawa, G. T. Mangum, B. W. Pfeiffer, E. R.
Published:
20080101
Source:
National Inst. of Standards and Technology (Gaithersburg, MD United States)
Pages:
16
Contract #:
None
Abstract:
As part of a program to disseminate the International Temperature Scale of 1990 (ITS-90), NIST provides thermometric fixed-point cells and high-purity metals for constructing fixed-point cells, certified as Standard Reference Materials (SRMs) for the range 29.7646 degrees C to 961.78 degrees C. SRM metals of indium, tin, zinc, aluminum and silver, =99.9999% pure, may be used to construct fixed-point cells that cover the range 156.5985 degrees C to 961.78 degrees C. SRMs of large freezing-point cells of tin (231.928 degrees C) and zinc (419.527 degrees C) are for use in calibrating standard platinum resistance thermometers in accordance with the ITS-90. SRMs of small fixed-point cells are for use in calibrating small thermometers, e.g., thermistors, over the range 29.7646 degrees C to 156.5985 degrees C. These SRMs and their applications will be discussed.
Language:
English

Title:
Hot Deformation of Ti-6Al-4V Single-Colony Samples (Preprint)
Document ID:
20090004561
Report #:
AD-A490769, AFRL-RX-WP-TP-2008-4343
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Salem, A A Semiatin, S L
Published:
20080201
Source:
Air Force Research Lab. (Wright-Patterson AFB, OH United States)
Pages:
25
Contract #:
None
Abstract:
The hot deformation response of lamellar colonies of Ti-6Al-4V was established via uniaxial compression testing. For this purpose, samples with a rectangular cross section were cut from single colonies grown using a float-zone technique and then tested at 815 degrees Celsius. Each sample was oriented for single slip along one of seven different slip system in the alpha phase. Measurements of the critical resolved shear stress (CRSS) at yielding and the subsequent flow behavior revealed a strong dependence of mechanical behavior on colony orientation/activated slip system. The anisotropy in the CRSS and the tendency for flow softening at large strains was rationalized on the basis of the burgers orientation relationship between the alpha (hcp) lamellae and the beta (bcc) matrix and hence the orientation of alpha slip directions relative to those in the beta phase.
Language:
English
Notes:
Submitted for publication to the International Journal of Plasticity

26-02 BERYLLIUM
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

26-03 LIQUID METALS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Experimental Studies of Metal-Silicate Partitioning of Sb: Implications for the Terrestrial and Lunar Mantles
Document ID:
20090004461
Report #:
None
Sales Agency:
Other Sources Copyright
Author(s):
Righter, K. (NASA Johnson Space Center) Humayun, M. (Chicago Univ.) Campbell, A.J. (Chicago Univ.) Danielson, L. (NASA Johnson Space Center) Hill, D. (Arizona Univ.) Drake, M.J. (Arizona Univ.)
Published:
20090101
Source:
NASA Johnson Space Center (Houston, TX, United States)
Pages:
68
Contract #:
None
Abstract:
The terrestrial mantle has a well defined Sb depletion of approximately 7 plus or minus 1 (Jochum and Hofmann, 1997), and the lunar mantle is depleted relative to the Earth by a factor of approximately 50 plus or minus 5 (Wolf and Anders, 1980). Despite these well defined depletions, there are few data upon which to evaluate their origin whether due to volatility or core formation. We have carried out a series of experiments to isolate several variables such as oxygen fugacity, temperature, pressure, and silicate and metallic melt compositions, on the magnitude of D(sup met/sil) (sub Sb). The activity of Sb in FeNi metal is strongly composition dependent such that solubility of Sb as a function of fO2 must be corrected for the metal composition. When the correction is applied, Sb solubility is consistent with 3+ valence. Temperature series (at 1.5 GPa) shows that D(sup met/sil) (sub Sb) decreases by a factor of 100 over 400 C, and a pressure series exhibits an additional decrease between ambient pressure (100 MPa) and 13 GPa. A strong dependence upon silicate melt composition is evident from a factor of 100 decrease in D(sup met/sil) (sub Sb) between nbo/t values of 0.3 and 1.7. Consideration of all these variables indicates that the small Sb depletion for the Earth's mantle can be explained by high PT equilibrium partitioning between metal and silicate melt (D(sup met/sil) (sub Sb) =5). The relatively large lunar Sb depletion can also be explained by segregation of a small metallic core, at lower pressure conditions where D(sup met/sil) (sub Sb) is much higher (2500).
Language:
English
Notes:
Submitted to Geochemicica Acta and to be published in April 2009

26-04 STEEL
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

26-05 TITANIUM
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
High Temperature Materials for Thin-Film Thermocouples on Silicon Wagers
Document ID:
20090004533
Report #:
PB2008-105962
Sales Agency:
CASI Hardcopy A03 No Copyright
Author(s):
Kreider, K. G. Gillen, G.
Published:
20080101
Source:
National Inst. of Standards and Technology (Gaithersburg, MD, United States)
Pages:
14
Contract #:
None
Abstract:
We are developing an instrumented calibration wafer for radiometric temperature measurements in rapid thermal processing (RTP) tools for semiconductor processing. The instrumented wafers has sputter deposited thin-film thermocouples to minimize the thermal disturbance of the wafer by the sensors. The NIST calibration wafer also employs platinum-palladium wire thermocouples to achieve a combined standard uncertainty of 0.4 deg C in temperature measurement of the thin-film thermocouple junction at 900 deg C. The high temperatures of the wafer has required the development of new thin-film material systems. We report the results of our testing and characterization of sputtered platinum, palladium, rhodium, and iridium thin films using titanium bond coats on thermally oxidized silicon wafers. Depth profiling with secondary ion mass spectrometry was used to determine the diffusion profiles from the metal film to the silicon after heat treatments as high as 1000 degrees C. Electron microscopy and optical microscopy were used to follow reactions and the deterioration of the thermoelectric films. In addition, performance tests up to 1000 degrees C in the NIST RTP test bed were used to determine the stability of the material systems.
Language:
English

Title:
Thermoelectric Properties of Self Assembled TiO2/SnO2 Nanocomposites
Document ID:
20090004672
Report #:
E-16834
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Dynys, Fred (NASA Glenn Research Center) Sayir, Ali (Case Western Reserve Univ.) Sehirlioglu, Alp (Case Western Reserve Univ.)
Published:
20080526
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
14
Contract #:
None
Abstract:
Recent advances in improving efficiency of thermoelectric materials are linked to nanotechnology. Thermodynamically driven spinodal decomposition was utilized to synthesize bulk nanocomposites. TiO2/SnO2 system exhibits a large spinodal region, ranging from 15 to 85 mole % TiO2. The phase separated microstructures are stable up to 1400 C. Semiconducting TiO2/SnO2 powders were synthesized by solid state reaction between TiO2 and SnO2. High density samples were fabricated by pressureless sintering. Self assemble nanocomposites were achieved by annealing at 1000 to 1350 C. X-ray diffraction reveal phase separation of (Ti(x)Sn(1-x))O2 type phases. The TiO2/SnO2 nanocomposites exhibit n-type behavior; a power factor of 70 W/mK2 at 1000 C has been achieved with penta-valent doping. Seebeck, thermal conductivity, electrical resistivity and microstructure will be discussed in relation to composition and doping.
Language:
English
Notes:
European Materials Resource Society Conference Strasbourg 26-30 May 2008

Title:
Effect of Upper-Cycle Temperature on the Load-Biased, Strain-Temperature Response of NiTi
Document ID:
20090004683
Report #:
E-16859
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Padula, Santo, II (NASA Glenn Research Center) Vaidyanathan, Raj (University of Central Florida) Gaydosh, Darrell (Ohio Aerospace Inst.) Noebe, Ronald (NASA Glenn Research Center) Bigelow, Glen (NASA Glenn Research Center) Garg, Anita (Toledo Univ.)
Published:
20080921
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
17
Contract #:
None
Abstract:
Over the past decade, interest in shape memory alloy based actuators has increased as the primary benefits of these solid-state devices have become more apparent. However, much is still unknown about the characteristic behavior of these materials when used in actuator applications. Recently we have shown that the maximum temperature reached during thermal cycling under isobaric conditions could significantly affect the observed mechanical response of NiTi (55 wt% Ni), especially the amount of transformation strain available for actuation and thus work output. This investigation extends that original work to ascertain whether further increases in the upper-cycle temperature would produce additional improvement in the work output of the material, which has a stress-free Af of 113 oC, and to determine the optimum cyclic conditions. Thus, isobaric, thermal-cycle experiments were conducted in the aforementioned alloy at various stress levels from 50-300 MPa using upper-cycle temperatures of 165, 200, 230, 260, 290, 320 and 350 oC. The data indicated that the amount of applied stress influenced the transformation strain available in the system, as would be expected. However, the maximum temperature reached during the thermal excursion also plays a role in determining the transformation strain, with the maximum transformation strain being developed by thermal cycling to 290 oC. In situ, neutron diffraction showed that the differences in transformation strain were related to differences in martensite texture within the microstructure when cycling to different upper-cycle temperatures. Hence, understanding this effect is important to optimizing the operation of SMA-based actuators and could lead to new methods for processing and training shape memory alloys for optimal performance.
Language:
English
Notes:
The International Conference on Shape Memory and Superelastic Technologies (SMST) 2008 Stresa 21-25 sEP. 2008

26-06 REFRACTORY METALS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Structural Benchmark Creep Testing for the Advanced Stirling Convertor Heater Head
Document ID:
20090004420
Report #:
NASA/TM-2008-215435, AIAA-2008-5774
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Krause, David L. (NASA Glenn Research Center) Kalluri, Sreeramesh (Ohio Aerospace Inst.) Bowman, Randy R. (NASA Glenn Research Center) Shah, Ashwin R. (Sest, Inc.)
Published:
20081101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
20
Contract #:
None
Abstract:
The National Aeronautics and Space Administration (NASA) has identified the high efficiency Advanced Stirling Radioisotope Generator (ASRG) as a candidate power source for use on long duration Science missions such as lunar applications, Mars rovers, and deep space missions. For the inherent long life times required, a structurally significant design limit for the heater head component of the ASRG Advanced Stirling Convertor (ASC) is creep deformation induced at low stress levels and high temperatures. Demonstrating proof of adequate margins on creep deformation and rupture for the operating conditions and the MarM-247 material of construction is a challenge that the NASA Glenn Research Center is addressing. The combined analytical and experimental program ensures integrity and high reliability of the heater head for its 17-year design life. The life assessment approach starts with an extensive series of uniaxial creep tests on thin MarM-247 specimens that comprise the same chemistry, microstructure, and heat treatment processing as the heater head itself. This effort addresses a scarcity of openly available creep properties for the material as well as for the virtual absence of understanding of the effect on creep properties due to very thin walls, fine grains, low stress levels, and high-temperature fabrication steps. The approach continues with a considerable analytical effort, both deterministically to evaluate the median creep life using nonlinear finite element analysis, and probabilistically to calculate the heater head s reliability to a higher degree. Finally, the approach includes a substantial structural benchmark creep testing activity to calibrate and validate the analytical work. This last element provides high fidelity testing of prototypical heater head test articles; the testing includes the relevant material issues and the essential multiaxial stress state, and applies prototypical and accelerated temperature profiles for timely results in a highly controlled laboratory environment. This paper focuses on the last element and presents a preliminary methodology for creep rate prediction, the experimental methods, test challenges, and results from benchmark testing of a trial MarM-247 heater head test article. The results compare favorably with the analytical strain predictions. A description of other test findings is provided, and recommendations for future test procedures are suggested. The manuscript concludes with describing the potential impact of the heater head creep life assessment and benchmark testing effort on the ASC program.
Language:
English
Notes:
Sixth International Energy Conversion Engineering Conference (IECEC) Cleveland, OH 28-30 Jul. 2008

26-07 METALLURGY
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.

27-01 PLASTICS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Evaluation of Acoustic Emission NDE of Kevlar Composite Over Wrapped Pressure Vessels
Document ID:
20090004558
Report #:
NASA/TM-2008-215558, L-19534
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Horne, Michael R. (National Inst. of Aerospace) Madaras, Eric I. (NASA Langley Research Center)
Published:
20081201
Source:
NASA Langley Research Center (Hampton, VA, United States)
Pages:
36
Contract #:
None
Abstract:
Pressurization and failure tests of small Kevlar/epoxy COPV bottles were conducted during 2006 and 2007 by Texas Research Institute Austin, Inc., at TRI facilities. This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. Results of some of the tests indicate a possibility that AE can be used to track the stress-rupture degradation of COPV vessels.
Language:
English

27-02 ADHESIVES
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Adaptive Control of Freeze-Form Extrusion Fabrication Processes (Preprint)
Document ID:
20090004649
Report #:
AD-A490822
Sales Agency:
Defense Technical Information Center (DTIC) No Copyright
Author(s):
Zhao, Xiyue Landers, Robert G Leu, Ming C
Published:
20080501
Source:
Missouri Univ. (Rolla, MO United States)
Pages:
41
Contract #:
FA8650-04-C-5704
Abstract:
Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing process that extrudes high solids loading aqueous ceramic pastes in a layer-by-layer fashion below the paste freezing temperature for component fabrication. Due to effects such as the air bubble release, agglomerate breakdown, change in paste properties during extrusion as a result of liquid phase migration, etc., the extrusion force is difficult to control. In this paper, an adaptive controller is proposed to regulate the extrusion force. Recursive Least Squares is used to estimate extrusion force model parameters during fabrication and a low-order control scheme capable of tracking general reference trajectories is designed and implemented to regulate the extrusion process. The controller is implemented to regulate the extrusion process. The controller is implemented for sinusoidal, triangular, and square reference trajectories and the results demonstrate excellent tracking performance of the adaptive extrusion force controller. Several parts were fabricated with the adaptive extrusion force controller. These results illustrate the need for extrusion force control and that variable reference extrusion.
Language:
English
Notes:
Submitted to the 2008 ASME Dynamic Systems and Control Conference held in Ann Arbor, MI

27-03 CERAMICS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Aerothermodynamic Testing and Boundary Layer Trip Sizing of the HIFiRE Flight 1 Vehicle
Document ID:
20090004557
Report #:
None
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Berger, Karen T. (NASA Langley Research Center) Greene, Frank A. (NASA Langley Research Center) Kimmel, Roger (Air Force Research Lab.) Alba, Christopher (Minnesota Univ.) Johnson, Heath (Minnesota Univ.)
Published:
20080101
Source:
NASA Langley Research Center (Hampton, VA, United States)
Pages:
22
Contract #:
None
Abstract:
An experimental wind tunnel test was conducted in the NASA Langley Research Center s 20-Inch Mach 6 Air Tunnel in support of the Hypersonic International Flight Research Experimentation Program. The information in this article is focused on the Flight 1 configuration, the first in a series of flight experiments. The article documents experimental measurements made over a Reynolds numbers range of 2.1x10(exp 6)/ft to 5.6x10(exp 6)/ft and angles of attack of -5 to +5 deg on several scaled ceramic heat transfer models of the Flight 1 configuration. Global heat transfer was measured using phosphor thermography and the resulting images and heat transfer distributions were used to infer the state of the boundary layer on the vehicle windside and leeside surfaces. Boundary layer trips were used to force the boundary layer turbulent and the experimental data highlighted in this article were used to size and place the boundary layer trip for the flight vehicle. The required height of the flight boundary layer trip was determined to be 0.079 in and the trip was moved from the design location of 7.87 in to 20.47 in to ensure that augmented heating would not impact the laminar side of the vehicle. Allowable roughness was selected to be 3.2x10(exp -3) in.
Language:
English
Notes:
To be published in Journal of Spacecraft and Rockets, volume 45, no. 6, pp. 1117-1124, Dec. 2008

Title:
Performance of the THS4302 and the Class V Radiation-Tolerant THS4304-SP Silicon Germanium Wideband Amplifiers at Extreme Temperatures
Document ID:
20090004673
Report #:
None
Sales Agency:
CASI Hardcopy A01 Copyright
Author(s):
Patterson, Richard L. (NASA Glenn Research Center) Elbuluk, Malik (Akron Univ.) Hammoud, Ahmad (ASRC Aerospace Corp.) VanKeuls, Frederick W. (Ohio Aerospace Inst.)
Published:
20090101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
5
Contract #:
NNC06BA07B
Abstract:
This report discusses the performance of silicon germanium, wideband gain amplifiers under extreme temperatures. The investigated devices include Texas Instruments THS4304-SP and THS4302 amplifiers. Both chips are manufactured using the BiCom3 process based on silicon germanium technology along with silicon-on-insulator (SOI) buried oxide layers. The THS4304-SP device was chosen because it is a Class V radiation-tolerant (150 kRad, TID silicon), voltage-feedback operational amplifier designed for use in high-speed analog signal applications and is very desirable for NASA missions. It operates with a single 5 V power supply [1]. It comes in a 10-pin ceramic flatpack package, and it provides balanced inputs, low offset voltage and offset current, and high common mode rejection ratio. The fixed-gain THS4302 chip, which comes in a 16-pin leadless package, offers high bandwidth, high slew rate, low noise, and low distortion [2]. Such features have made the amplifier useful in a number of applications such as wideband signal processing, wireless transceivers, intermediate frequency (IF) amplifier, analog-to-digital converter (ADC) preamplifier, digital-to-analog converter (DAC) output buffer, measurement instrumentation, and medical and industrial imaging.
Language:
English

Title:
Doping of BiScO3-PbTiO3 Ceramics for Enhanced Properties
Document ID:
20090004693
Report #:
E-16871
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Sehirlioglu, Alp (Case Western Reserve Univ.) Sayir, Ali (NASA Glenn Research Center) Dynys, Fred (NASA Glenn Research Center)
Published:
20081005
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
19
Contract #:
AFOSR FA-9550-06.1-0260
Abstract:
High-temperature piezoelectrics are a key technology for aeronautics and aerospace applications such as fuel modulation to increase the engine efficiency and decrease emissions. The principal challenge for the insertion of piezoelectric materials is the limitation on upper use temperature which is due to low Curie-Temperature (T(sub c) and increasing electrical conductivity. BiScO3 -PbTiO3 (BS-PT) system is a promising candidate for improving the operating temperature for piezoelectric actuators due to its high TC (>400 C). Effects of Zr and Mn doping of the BS-PT ceramics have been studied and all electrical and electromechanical properties for Sc-deficient and Ti-deficient BS- PT ceramics are reported as a function of electrical field and temperature. Donor doping with Zr and Mn (in Sc deficient compositions) increased the DC-resistivity and decreased tan at all temperatures. Resulting ceramics exhibited saturated hysteresis loops with low losses and showed no dependence on the applied field (above twice the coercive field) and measurement frequency.
Language:
English
Notes:
Materials Science and Technology Meeting ASM/ACERS Pittsburgh, PA 5-9 Oct. 2008

27-04 ELASTOMERS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

27-05 GRAPHITE
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Study of Diamond Film Growth through Etching Graphite by Hydrogen in Hot Filament Chemical Vapor Deposition Reactor
Document ID:
20090004844
Report #:
INPE-14804-TDI/1247
Sales Agency:
CASI CD-ROM C01 Copyright
Author(s):
de Melo Silva, William (Instituto Nacional de Pesquisas Espacias)
Published:
20080101
Source:
Instituto Nacional de Pesquisas Espacias (Sao Jose dos Campos, Brazil)
Pages:
104
Contract #:
None
Abstract:
This work presents a study regarding the process of etching to the graphite by hydrogen with intention to elucidate the growth of diamond films in a reactor of chemical vapor deposition activated by hot filament where the graphite is the carbon source only. Morphological and structural aspects are analyzed systematic through images of electronic microscopy of scanning and spectroscopy of Raman scattering in such a way in the graphite (etching by hydrogen before and after) as in the diamond films obtained. In these analyses, the high dependence graphite temperature showed influence to the rate of nucleation and diamond film growth on the substrate. The results obtained had shown that the chemical graphite erosion by hydrogen induced structural changes in its surface. Such graphite crystalline lattice alterations had been investigated from relation I(sub D)/I(sub G) that presented a maximum value in 900 C when compared with the graphite surface in ambient temperature before the etching of hydrogen. In the films grown with a time of deposition of 15 minutes under temperatures in graphite of the 600 and 700 C the high rate of nucleation had been verified, whereas, for times of growth of 30 minutes the films are continuous, presenting surfaces total covered and supreme between 1 and 3 microns with a good quality of diamond, mainly for temperatures of 600 and 700 C. The carbon type diamond in the films values had been calculated for the times of growth of 15, 30 and 60 minutes and are in accordance with the behavior of nanocrystalline diamonds, that is, they increase the pureness of in agreement film the addition of the temperature. In general, the diamond films morphology grown from a solid carbon source is similar to the found ones in conventional diamond depositions, where the obtained Raman spectra show to a characteristic peak in 1332/cm and a carbon band in, approximately, 1550/cm of low intensity. Results regarding the dissolution of carbon, in solid graphite state, by the activation of species of the gaseous phase and carbon atom deposition in the diamond form in the film were verified by the calculation of the etching to the graphite for hydrogen efficiency process of resulting indirectly in the diamond (EP) formation. Such efficiency was calculated through a relation enters the measures of mass of the lost graphite and of the diamond mass it after gains the deposition in the substratum. However, the main parameters for the diamond growth, such as: pressure, temperature and flow had been varied and a maximum of efficiency EP was reached for 30 Torr pressures, 700 C temperature and 100 sccm hydrogen flow.
Language:
Portuguese

27-06 POLYMERS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Nanocomposites in Aerospace Applications
Document ID:
20090004681
Report #:
E-16855
Sales Agency:
Other Sources No Copyright
Author(s):
Meador, Michael A. (NASA Glenn Research Center)
Published:
20080101
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
68
Contract #:
None
Abstract:
Weight, durability, and functionality are critical concerns for any aerospace system. Reductions in aircraft weight can enable increased payload capacity, improved maneuverability and decreased fuel consumption and emissions. Decreases in spacecraft weight lead to reduced launch costs and enable increased payload capacity. At the present time, it costs between $10,000 and $20,000 per pound to launch an item on the Space Shuttle. Durability is an important criterion not only because it affects vehicle safety, but also because it can impact maintenance costs and schedule. Unexpected delays in the launch of the Space Shuttle can costs millions of dollars in operations costs. For long duration space missions, failure in a critical component can jeopardize the success of the mission. Performance and functionality are also key drivers for aerospace systems. Vehicle performance impacts fuel consumption and emissions as well as survivability for military aircraft. The use of multifunctional materials and components, that combine the ability to bear a mechanical load with other functions, such as lightning strike protection or damage sensing, is becoming increasingly desirable because it can lead to enhanced performance and also enable weight reductions. Adaptive materials (shape memory alloys and polymers, piezoelectric materials) are also receiving considerable attention because they can enable radical new designs for aircraft and spacecraft that incorporate morphing structures, such as aircraft wings that can bend or change their shape and aerodynamics thereby eliminating the need for ailerons. Use of adaptive structures can enable enhanced vehicle performance and fuel efficiency, and lead to reduced maintenance and improved durability. These materials could find use in advanced aircraft designs, such as the Silent Aircraft concept being developed by a team from Cambridge University and MIT.
Language:
English

28-01 LIQUID PROPELLANTS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

Title:
Liquid Methane/Liquid Oxygen Propellant Conditioning Feed System (PCFS) Test Rigs
Document ID:
20090004695
Report #:
E-16872
Sales Agency:
CASI Hardcopy A03 Copyright
Author(s):
Skaff, A. (Sierra Lobo, Inc.) Grasl, S. (Sierra Lobo, Inc.) Nguyen, C. (Sierra Lobo, Inc.) Hockenberry S. (Sierra Lobo, Inc.) Schubert, J. (NASA Glenn Research Center) Arrington, L. (NASA Glenn Research Center) Vasek, T. (NASA Glenn Research Center)
Published:
20081208
Source:
NASA Glenn Research Center (Cleveland, OH, United States)
Pages:
17
Contract #:
NNCO5CA95C
Abstract:
As part of their Propulsion and Cryogenic Advanced Development (PCAD) program, NASA has embarked upon an effort to develop chemical rocket engines which utilize non-toxic, cryogenic propellants such as liquid oxygen (LO2) and liquid methane (LCH4). This effort includes the development and testing of a 100 lbf Reaction Control Engine (RCE) that will be used to evaluate the performance of a LO2/LCH4 rocket engine over a broad range of propellant temperatures and pressures. This testing will take place at NASA-Glenn Research Center's (GRC) Research Combustion Laboratory (RCL) test facility in Cleveland, OH, and is currently scheduled to begin in late 2008. While the initial tests will be performed at sea level, follow-on testing will be performed at NASA-GRC's Altitude Combustion Stand (ACS) for altitude testing. In support of these tests, Sierra Lobo, Inc. (SLI) has designed, developed, and fabricated two separate portable propellant feed systems under the Propellant Conditioning and Feed System (PCFS) task: one system for LCH4, and one for LO2. These systems will be capable of supplying propellants over a large range of conditions from highly densified to several hundred pounds per square inch (psi) saturated. This paper presents the details of the PCFS design and explores the full capability of these propellant feed systems.
Language:
English
Notes:
Chemical Propulsion Information Agency - JANNAF 6th Modeling and Simulation JANNAF 4th Liquid Propulsion JANNAF 3rd Spacecraft Propulsion Joint Subcommittee Meeting Orland, FL Orland, FL Orland, FL 8-12 Dec. 2008 8-12 Dec. 2008 8-12 Dec. 2008

28-02 SOLID PROPELLANTS
Feb 8, 2009 -- Additions to the NASA scientific and technical information knowledge base

No records are available for this topic on this date.