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Sample records for densification additive estudo

  1. Influence of oxide-based sintering additives on densification and mechanical behavior of tricalcium phosphate (TCP).

    PubMed

    Bhatt, Himesh A; Kalita, Samar J

    2007-05-01

    In this research, we studied and analyzed the effects of four different oxide-based sintering additives on densification, mechanical behavior, biodegradation and biocompatibility of tricalcium phosphate (TCP) bioceramics. Selective sintering additives were introduced into pure TCP ceramics, in small quantities, through homogeneous mixing, using a mortar and pestle. The consequent powders of different compositions were pressed into cylindrical compacts, uniaxially and sintered at elevated temperatures, 1150 degrees C and 1250 degrees C, separately in a muffle furnace. X-ray powder diffraction technique was used to analyze the phase-purity of TCP after sintering. Hardness of these sintered specimens was evaluated using a Vickers hardness tester. Sintered cylindrical samples were tested under uniaxial compressive loading, as a function of composition to determine their failure strength. Biodegradation studies conducted using simulated body fluid under dynamic environment, revealed that these additives could control the rate of resorption and hardness degradation of TCP ceramics. PMID:17211718

  2. Field-assisted Densification of Superhard B6O Materials with Y2O3/Al2O3 Addition

    NASA Astrophysics Data System (ADS)

    Herrmann, M.; Raethel, J.; Sempf, K.; Thiele, M.; Bales, A.; Sigalas, I.

    B6O is a possible candidate of superhard materials with a hardness of 45 GPa measured on single crystals. Up to now, densification of these materials was only possible at high pressure. However, recently it was found that different oxides can be utilized as effective sintering additives. In this work the effect of addition of Y2O3/Al2O3 on the densification behaviour as a function of applied pressure, its microstructure evolution, and resulting mechanical properties were investigated. A strong dependence of the densification with increasing pressure was found. The material revealed characteristic triple junctions filled with amorphous residue composed of B2O3, Al2O3 and Y2O3, while no amorphous grain-boundary films were observed along internal interfaces. Mechanical testing revealed on average hardness of 33 GPa, a fracture toughness of 4 MPam1/2, and a strength value of 500 MPa.

  3. Densification of Reaction Bonded Silicon Nitride with the Addition of Fine Si Powder Effects on the Sinterability and Mechanical Properties

    SciTech Connect

    Lee, Sea-Hoon; Cho, Chun-Rae; Park, Young-Jo; Ko, Jae-Woong; Kim, Hai-Doo; Lin, Hua-Tay; Becher, Paul F

    2013-01-01

    The densification behavior and strength of sintered reaction bonded silicon nitrides (SRBSN) that contain Lu2O3-SiO2 additives were improved by the addition of fine Si powder. Dense specimens (relative density: 99.5%) were obtained by gas-pressure sintering (GPS) at 1850oC through the addition of fine Si. In contrast, the densification of conventional specimens did not complete at 1950oC. The fine Si decreased the onset temperature of shrinkage and increased the shrinkage rate because the additive helped the compaction of green bodies and induced the formation of fine Si3N4 particles after nitridation and sintering at and above 1600oC. The amount of residual SiO2 within the specimens was not strongly affected by adding fine Si powder because most of the SiO2 layer that had formed on the fine Si particles decomposed during nitridation. The maximum strength and fracture toughness of the specimens were 991 MPa and 8.0 MPa m1/2, respectively.

  4. Tile densification with TEOS

    NASA Technical Reports Server (NTRS)

    Ecord, G. M.; Schomburg, C.

    1981-01-01

    Densification process uses brushed or sprayed coating of tetraethyl orthosilicate. Liquid is applied and cured in three steps; tile weight increase averages 0.15 g per square centimeter. TEOS liquid is prepared by mixing TEOS with hydrochloric acid and adding marking dye. TEOS application provides variable stiffness, strength, and penetration. Surface of tile shows no buidup and is more durable for additional coatings.

  5. Enhanced densification of metal powders by transformation-mismatch plasticity

    SciTech Connect

    Schuh, C.; Noel, P.; Dunand, D.C.

    2000-05-11

    The densification of titanium powders is investigated in uniaxial die pressing experiments carried out isothermally at 980 C (in the {beta}-field of titanium) and during thermal cycling between 860 and 980 C (about the {alpha}/{beta} phase transformation of titanium). Thermal cycling is found to enhance densification kinetics through the emergence of transformation-mismatch plasticity (the mechanism responsible for transformation superplasticity) as a densification mechanism. The isothermal hot-pressing data compare favorably with existing models of powder densification, and these models are successfully adapted to the case of transformation-mismatch plasticity during thermal cycling. Similar conclusions are reached for the densification of titanium powders containing 1, 5, or 10 vol.% ZrO{sub 2} particles. However, the addition of ZrO{sub 2} hinders densification by dissolving in the titanium matrix during the hot-pressing procedure.

  6. Effect of an organic additive on the rheology of an aluminous cement paste and consequences on the densification of the hardened material

    NASA Astrophysics Data System (ADS)

    El Hafiane, Y.; Smith, A.; Bonnet, J. P.; Tanouti, B.

    2005-03-01

    The material used in the present work is Secar 71 (Lafarge) mixed with water containing an organic additive (acetic acid noted HOAc). The rheological behavior of these pastes is studied. The best dispersion is obtained when the mass content of the additive with respect to the cement is equal to 0.5%. The microstructural characterizations of samples aged 4 days at 20° C and 95 % relative humidity reveal a significant increase in the density and a reduction in porosity for very small percentages of additive. The remarkable effect of the acetic acid on the microstructure of hardened material is correlated with its good dispersing action.

  7. Influence of La2Zr2O7 Additive on Densification and Li+ Conductivity for Ta-Doped Li7La3Zr2O12 Garnet

    NASA Astrophysics Data System (ADS)

    Huang, Xiao; Shen, Chen; Rui, Kun; Jin, Jun; Wu, Meifen; Wu, Xiangwei; Wen, Zhaoyin

    2016-10-01

    A high-conductivity solid electrolyte, La2Zr2O7 (LZO) added to Li6.4La3Zr1.4Ta0.6O12 (LLZTO), was prepared via conventional solid-state reactions and sintered at 1100°C for 10 h, which is tens of Celsius degrees lower than the typical sintering temperature for LLZTO. The addition of LZO did not bring in any impurities. LZO acted as a sintering aid to densify the LLZTO from a relative density of 77% up to 90%, which was comparable to that of pure LLZTO sintered at 1200°C. The 6 wt.% LZO-LLZTO samples sintered at 1100°C and 1200°C exhibited a room-temperature conductivity of 1.92 × 10-4 S/cm and 5.84 × 10-4 S/cm, respectively, which were higher than that of pure LLZTO samples. Glass-like phases observed at grain boundaries in LZO-LLZTO ceramics indicated that LZO promoted the formation of the glass-like phases binding together LLZTO grains and thus leading to enhanced density and conductivity of LLZTO.

  8. Influence of La2Zr2O7 Additive on Densification and Li+ Conductivity for Ta-Doped Li7La3Zr2O12 Garnet

    NASA Astrophysics Data System (ADS)

    Huang, Xiao; Shen, Chen; Rui, Kun; Jin, Jun; Wu, Meifen; Wu, Xiangwei; Wen, Zhaoyin

    2016-08-01

    A high-conductivity solid electrolyte, La2Zr2O7 (LZO) added to Li6.4La3Zr1.4Ta0.6O12 (LLZTO), was prepared via conventional solid-state reactions and sintered at 1100°C for 10 h, which is tens of Celsius degrees lower than the typical sintering temperature for LLZTO. The addition of LZO did not bring in any impurities. LZO acted as a sintering aid to densify the LLZTO from a relative density of 77% up to 90%, which was comparable to that of pure LLZTO sintered at 1200°C. The 6 wt.% LZO-LLZTO samples sintered at 1100°C and 1200°C exhibited a room-temperature conductivity of 1.92 × 10-4 S/cm and 5.84 × 10-4 S/cm, respectively, which were higher than that of pure LLZTO samples. Glass-like phases observed at grain boundaries in LZO-LLZTO ceramics indicated that LZO promoted the formation of the glass-like phases binding together LLZTO grains and thus leading to enhanced density and conductivity of LLZTO.

  9. Isothermal densification and metamorphism of new snow

    NASA Astrophysics Data System (ADS)

    Schleef, S.; Loewe, H.; Schneebeli, M.

    2012-12-01

    The interplay between overburden stress and surface energy induced growth and coarsening is relevant for the densification of snow and porous ice at all densities. The densification of new snow is amenable to high precision experiments on short time scales. To this end we investigate the coupling of densification and metamorphism of new snow via time-lapse tomography experiments in the laboratory. We compare the evolution of density, strain, and specific surface area to previous long-time metamorphism experiments of snow and creep of polycrystalline ice. Experimental conditions are tailored to the requirements of time-lapse tomography and the measurements are conducted under nearly isothermal conditions at -20°C with a duration of two days. Images were taken with temporal resolution of a few hours which reveal precise details of the microstructure evolution due to sintering and compaction. We used different crystal shapes of natural new snow and snow samples obtained by sieving crystals grown in a snowmaker in the laboratory. To simulate the effect of overburden stress due to an overlying snowpack additional weights were applied to the sample. As expected we find an influence of the densification rate on initial density and overburden stress. We calculated strain rates and identified a transient creep behavior with a similar power law for all crystal types which substantially differs from the Andrade creep of polycrystalline ice. As a main result we found that the evolution of the specific surface area is independent of the density and follows a unique decay form for all measurements of each crystal type. The accuracy of the measurements allows to obtain a decay exponent for the SSA which is the same as previously obtained from the long-time regime during isothermal metamorphism after several months. Our preliminary results for all available types of new snow suggest a correlation between the initial density and SSA. We also find snow samples which coincide in

  10. Liquid propellant densification

    NASA Technical Reports Server (NTRS)

    Lak, Tibor I. (Inventor); Petrilla, Steve P. (Inventor); Lozano, Martin E. (Inventor)

    1997-01-01

    Super cooling the cryogenic liquid propellant in a vehicle propellant tank densities the propellant allowing the vehicle propellant tank to carry more fuel in the same volume tank while lowering the vapor pressure and thus the tank operating pressure. Lowering the tank operating pressure reduces the stress and therefore allows the walls of the tank to be thinner. Both the smaller tank volume and thinner tank wall results in an overall smaller and lighter vehicle with increased payload capability. The cryogenic propellant can be supercooled well below the normal boiling point temperature level by transporting the liquid propellant from the vehicle tanks to a ground based cooling unit which utilizes a combination of heat exchanger and compressor. The compressor lowers the coolant fluid bath pressure resulting in a low temperature boiling liquid which is subsequently used to cool the recirculating liquid. The cooled propellant is then returned to the vehicle propellant tank. In addition to reducing the vehicle size and weight the invention also allows location of the vent valve on the ground, elimination of on-board recirculation pumps or bleed systems, smaller and lighter engine pumps and valves, lighter and more stable ullage gas, and significant reduction in tank fill operation. All of these mentioned attributes provide lower vehicle weight and cost.

  11. Controlled densification of mullite for composite applications.

    SciTech Connect

    Cruse, T. A.

    1999-05-19

    As part of an effort to fabricate oxide-based fibrous monolithic ceramics, sintering of mullite has been examined. The effects of Y{sub 2}O{sub 3} additions on sinterability of sol-gel-derived mullite and on the resulting microstructure were evaluated over a range of compositions, sintering times, and temperatures. Electron microscopy, X-ray diffraction, differential thermal analysis, and density measurements indicated that the Y{sub 2}O{sub 3} additions promoted densification through formation of a Y-Si-Al-O liquid phase. This phase tended to solidify as a glass during normal processing, but could be crystallized by a two-step annealing process at 1300 and 1200 C. The four-point flexural strengths of mullite and mullite-5 Wt.% Y{sub 2}O{sub 3} were also examined.

  12. The affect of densification and dehydroxylation on the mechanical properties of stoichiometric hydroxyapatite bioceramics

    SciTech Connect

    Laasri, S.; Taha, M.; Laghzizil, A.; Hlil, E.K.; Chevalier, J.

    2010-10-15

    This paper reports the effects of processing densification on the mechanical properties of hydroxyapatite bioceramics. Densification of synthetic hydroxyapatite is conducted in the range 1000-1300 {sup o}C. X-ray diffraction and SEM microscopy are used to check the microstructure transformations. Vickers hardness, toughness and Young's modulus are analyzed versus the density and grain size. The sintering temperature and the particle size influence strongly the densification and the resulting mechanical properties. In addition, the critical sintering temperature appears around 1200 {sup o}C and the declined strength at the temperature up to 1200 {sup o}C is found sensitive to the dehydroxylation process of hydroxyapatite.

  13. Densification of functional plasma polymers by momentum transfer during film growth

    SciTech Connect

    Hegemann, Dirk; Koerner, Enrico; Blanchard, Noemi; Drabik, Martin; Guimond, Sebastien

    2012-11-19

    Functional plasma polymers were deposited from pure ethylene discharges and with the addition of carbon dioxide or ammonia. The incorporation of oxygen and nitrogen-containing functional groups depends on the fragmentation in the gas phase as well as on the densification during film growth. While a minimum energy per deposited carbon atom is required for cross-linking, the densification and accompanying reduction of functional group incorporation was found to scale linearly with momentum transfer through ion bombardment during film growth.

  14. Recent Advancements in Propellant Densification

    NASA Technical Reports Server (NTRS)

    McNelis, Nancy B.; Tomsik, Thomas M.

    1998-01-01

    Next-generation launch vehicles demand several technological improvements to achieve lower cost and more reliable access to space. One technology area whose performance gains may far exceed others is densified propellants. The ideal rocket engine propellant is characterized by high specific impulse, high density, and low vapor pressure. A propellant combination of liquid hydrogen and liquid oxygen (LH2/LOX) is one of the highest performance propellants, but LH2 stored at standard conditions has a relatively low density and high vapor pressure. Propellant densification can significantly improve this propellant's properties relative to vehicle design and engine performance. Vehicle performance calculations based on an average of existing launch vehicles indicate that densified propellants may allow an increase in payload mass of up to 5 percent. Since the NASA Lewis Research Center became involved with the National Aerospace Plane program in the 1980's, it has been leading the way in making densified propellants a viable fuel for next-generation launch vehicles. Lewis researchers have been working to provide a method and critical data for continuous production of densified hydrogen and oxygen.

  15. Task 4 supporting technology. Densification requirements definition and test objectives. Propellant densification requirements definition

    NASA Technical Reports Server (NTRS)

    Lak, Tibor; Weeks, D. P.

    1995-01-01

    The primary challenge of the X-33 CAN is to build and test a prototype LO2 and LH2 densification ground support equipment (GSE) unit, and perform tank thermodynamic testing within the 15 month phase 1 period. The LO2 and LH2 propellant densification system will be scaled for the IPTD LO2 and LH2 tank configurations. The IPTD tanks were selected for the propellant technology demonstration because of the potential benefits to the phase 1 plan: tanks will be built in time to support thermodynamic testing; minimum cost; minimum schedule risk; future testing at MSFC will build on phase 1 data base; and densification system will be available to support X-33 and RLV engine test at IPTD. The objective of the task 1 effort is to define the preliminary requirements of the propellant densification GSE and tank recirculation system. The key densification system design parameters to be established in Task 1 are: recirculation flow rate; heat exchanger inlet temperature; heat exchanger outlet temperature; maximum heat rejection rate; vent flow rate (GN2 and GH2); densification time; and tank pressure level.

  16. Densification and crystallization of zirconia thin films prepared by sol-gel processing

    SciTech Connect

    Schwartz, R.W.; Voigt, J.A.; Buchheit, C.D.; Boyle, T.J.

    1993-12-31

    We have investigated the effects of precursor nature and heat treatment schedule on the densification and crystallization behavior of sol-gel derived zirconia thin films. Precursor solutions were prepared from n-propanol, zirconium (IV) n-propoxide, and either acetic acid, or 2,4-pentanedione (acac) and water additions. By controlling the ligand type and ligand-to-metal ratio, we were able to prepare films which displayed significant differences in densification behavior. We attribute the dissimilarity in densification to variations in the nature of the as-deposited films, as influenced by ligand type and concentration. While the acac- derived film was a physical gel, (i.e., a physical aggregation of the oligomeric species), the acetic acid-derived film, which exhibited less consolidation, was a chemical gel that could not be redissolved in the parent solvent. Films prepared with large acac/metal ratios and small water additions exhibited minimal crosslinking at 25{degree}C, displayed the greatest consolidation ({approximately}86% shrinkage) and the highest refractive index (n = 2.071) when heat treated. These results indicate the importance that M-O-M bonds (crosslinks) formed at low temperature can have on densification behavior. We also report on the effects of heat-treatment schedules and ramp rates on densification behavior. All of the films of the present study crystallized into the cubic phase, at temperatures ranging from {approximately}400{degree}C to greater than 700{degree}C, depending on the heating rate.

  17. Painful connections: densification versus fibrosis of fascia.

    PubMed

    Pavan, Piero G; Stecco, Antonio; Stern, Robert; Stecco, Carla

    2014-01-01

    Deep fascia has long been considered a source of pain, secondary to nerve pain receptors becoming enmeshed within the pathological changes to which fascia are subject. Densification and fibrosis are among such changes. They can modify the mechanical properties of deep fasciae and damage the function of underlying muscles or organs. Distinguishing between these two different changes in fascia, and understanding the connective tissue matrix within fascia, together with the mechanical forces involved, will make it possible to assign more specific treatment modalities to relieve chronic pain syndromes. This review provides an overall description of deep fasciae and the mechanical properties in order to identify the various alterations that can lead to pain. Diet, exercise, and overuse syndromes are able to modify the viscosity of loose connective tissue within fascia, causing densification, an alteration that is easily reversible. Trauma, surgery, diabetes, and aging alter the fibrous layers of fasciae, leading to fascial fibrosis.

  18. Densification, microstructure and strength evolution in sintering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoping

    2000-10-01

    Powder metallurgy has the ability to fabricate high quality, complex components to close tolerances in an economical manner. In many applications, a high sintered density is desirable for an improved performance. However, sintering to a high density demands a large shrinkage, often resulting in difficulties with dimensional control. Recent studies indicate the occurrence of a sufficient densification requires a low in situ strength at high sintering temperatures. On the other hand, the low in situ strength often leads to component's distortion in response to the external forces, such as gravity. Unfortunately, lack of knowledge on strength evolution in sintering has been a major challenge to achieve an optimized combination of densification and shape retention. Therefore, the present study investigates strength evolution in sintering and the effects of processing factors. Experiments are performed on prealloyed bronze and elemental mixture of Fe-2Ni powders. For the bronze, a loose casting method is used to fabricate transverse rupture bars, while bars are injection molded for the Fe-2Ni. The in situ transverse rupture strength is measured using the Penn State Flaming Tensile Tester. Experimental results indicate a dependence of densification and strength on sintering temperature. High temperatures enhance densification and interparticle bonding, resulting in strong sintered structures. However, a low in situ strength at high test temperatures indicates the dominance of thermal softening. A strength model combining sintering theories and microstructural parameters is developed to predict both the in situ strength and the post-sintering strength. The model demonstrates the strength of the sintered materials depends on the inherent material strength, the square of neck size ratio, sintered density, and thermal softening. The model is verified by comparison of model predictions with experimental data of the bronze and Fe-2Ni. Compared to prior strength models, this

  19. The densification of layered polar firn

    NASA Astrophysics Data System (ADS)

    HöRhold, M. W.; Kipfstuhl, S.; Wilhelms, F.; Freitag, J.; Frenzel, A.

    2011-03-01

    High-resolution density profiles of 16 firn cores from Greenland and Antarctica are investigated in order to improve our understanding of the densification of layered polar firn. A vertical resolution of 1-5 mm enables us to study the detailed densification processes and the evolution of the layering and the resulting variability in density with increasing depth. The densification of layered firn is important for the process of air enclosure in ice and is connected with the observed formation of a nondiffusive zone. Our findings show the following. (1) Mean density profiles, obtained from high-resolution measurements, only partly show clear transitions in densification rate at densities of 550, 730, or 820-840 kg/m3, as they are commonly used in literature. (2) The density variability, induced by the layering, shows a similar pattern at all sites: high variabilities at the surface, a rapid drop to a relative minimum in variability at mean density of 600-650 kg/m3, followed by a second relative maximum. (3) This leads to increased variability at densities of the firn-ice transition for most of the sites. (4) The variability at the surface decreases with increasing mean annual temperature and accumulation rate, whereas the variability at the firn-ice transition increases. We can exclude a change in local climate conditions as an explanation for the density variability since the firn cores in this study cover a broad range in mean annual temperature, accumulation rate, and age. Overall, high-resolution density profiles deliver a more complex picture of compaction of polar firn as a layered granular medium than has been obtained from mean density profiles in the past.

  20. Evaluation of Liquefaction Susceptibility of Clean Sands after Blast Densification

    NASA Astrophysics Data System (ADS)

    Vega Posada, Carlos Alberto

    The effect of earthquakes on infrastructure facilities is an important topic of interest in geotechnical research. A key design issue for such facilities is whether or not liquefaction will occur during an earthquake. The consequences of this type of ground failure are usually severe, resulting in severe damage to a facility and in some cases the loss of human life. One approach to minimize the effect of liquefaction is to improve the ground condition by controlled blasting. The main limitations of the blast densification technique are that the design is mostly empirical and verification studies of densification have resulted in contradictory results in some case studies. In such cases, even though the ground surface settles almost immediately after blasting, common verification tests such as the cone penetration test (CPT), standard penetration test (SPT), and shear wave velocity test (Vs) suggest that the soil mass has not been improved at all. This raises concerns regarding the future performance of the soil and casts doubts on whether or not the improved deposit is still susceptible to liquefaction. In this work, a blast densification program was implemented at the Oakridge Landfill located in Dorchester County, SC, to gain information regarding the condition of a loose sand deposit during and after each blast event. In addition, an extensive laboratory testing program was conducted on reconstituted sand specimens to evaluate the mechanical behavior of saturated and gassy, medium dense sands during monotonic and cyclic loading. The results from the field and laboratory program indicate that gas released during blasting can remain trapped in the soil mass for several years, and this gas greatly affects the mechanical behavior of the sand. Gas greatly increases the liquefaction resistance of the soil. If the gas remains in the sand over the life of a project, then it will maintain this increased resistance to liquefaction, whether or not the penetration

  1. Densification effects on structural relaxation of polyolefins

    NASA Astrophysics Data System (ADS)

    Clark, Jason; Maranas, Janna K.

    2003-10-01

    We investigate the effect of densification on intramolecular and intermolecular chain packing and structural relaxation of four saturated hydrocarbon polymers: poly(ethylene propylene) (PEP), poly(ethylene butene), atactic polypropylene, and head-to-head polypropylene. Within this series, the local chain architecture, specifically the frequency and size of pendant groups, varies. Density changes of ρ0±5%, where ρ0 is the ambient density, are considered at a temperature of 400 K, which is well above the glass transition temperatures of all four polymers. Intramolecular chain packing remains nearly unchanged over this density range, and intermolecular packing shows a tendency towards closer and more efficient packing at higher densities. The effect of density on dynamics depends on the spatial scale considered. Self-intermediate scattering functions, as measured in incoherent quasielastic neutron scattering experiments, are calculated for spatial scales between 2.5 and 20 Å. At length scales less than the closest intermolecular spacing, densification has little effect on mobility. The largest effects are observed in the vicinity of the nearest chain spacing distance, where mobility is decreased and dynamic heterogeneity, as evidenced by the stretching parameter in stretched exponential fits, is increased with densification. At length scales approaching Rg, both effects level off and are slightly less than at spatial scales of interchain packing. The most flexible of the four materials, PEP, is least affected by density changes.

  2. Densification of nano-size powders. 1994 report

    SciTech Connect

    Chen, W.; Malghan, S.G.; Dapkunas, J.S.; Piermarini, G.; Pechenik, A.; Danforth, S.C.

    1994-06-01

    Green compacts from a nano-size silicon nitride powder were fabricated having density up to 67% of theoretical at 2.8 GPa pressure using liquid nitrogen and pentane as compaction lubricant media. Pressureless sintering of these transparent samples did not promote further densification beyond that obtained for the green state. To further increase the density of these samples, a hot-pressing device was designed. In a series of experiments, hot-pressing of these samples at.0.5 to 1.0 GPa and 800 C, followed by pressureless sintering at 1400 C was studied. The resulting silicon nitride ceramic had a Vickers hardness of 9.0 GPa while transparency under visible light was maintained. Without the use of hot pressing, the hardness obtained was 5.8 GPa. In addition, the effect of compaction pressure on densification was studied for nano-size Al{sub 2}O{sub 3} to further understand factors contributing to achieving high green densities. The dense Al{sub 2}O{sub 3} green samples were pressureless sintered to near full density at temperatures several hundred degrees lower than those needed for sintering low density green material.

  3. Sol-gel synthesis and densification of aluminoborosilicate powders. Part 2: Densification

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Selvaduray, Guna; Leiser, Daniel

    1992-01-01

    Aluminoborosilicate (ABS) powders, high in alumina content, were synthesized by the sol-gel process utilizing four different methods of synthesis. The effect of these methods on the densification behavior of ABS powder compacts was studied. Five regions of shrinkage in the temperature range 25-1184 C were identified. In these regions, the greatest shrinkage occurred between the gel-to-glass transition temperature (T sub g approximately equal to 835 C) and the crystallization transformation temperature (T sub t approximately equal 900 C). The dominant mechanism of densification in this range was found to be viscous sintering. ABS powders were amorphous to x-rays up to T sub t at which a multiphasic structure crystallized. No 2Al2O3.B2O3 was found in these powders as predicted in the phase diagram. Above T sub t, densification was the result of competing mechanisms including grain growth and boria fluxed viscous sintering. Apparent activation energies for densification in each region varied according to the method of synthesis.

  4. Characterization of CVI densification of ceramic composites

    SciTech Connect

    Starr, T.L.; Stock, S.R.; Lee, S.

    1995-05-01

    Ceramic matrix composites promise higher operating temperature and better thermodynamic efficiency in many enregy conversion systems. In particular, composites fabricated by the chemical vapor infiltration (CVI) process have excellent mechanical properties and, using the forced flow-thermal gradient variation, good processing economics in small scale demonstrations. Scale-up to larger, more complex shapes requires understanding of gas flow through the fiber preform and of the relationship between fiber architecture and densification behavior. This understanding is needed for design of preforms for optimum infiltration. The objective of this research is to observe the deposition of matrix material in the pores of a ceramic fiber preform at various stages of the CVI process. These observations allow us to relate local deposition rates in various regions of the composite to the connectivity of the surrounding network of porosity and to better model the relationship between gas transport and fiber architecture in CVI preforms. Our observation of the CVI process utilizes high resolution X-ray tomographic microscopy (XTM) in collaboration with Dr. John Kinney at Lawrence Livermore National Laboratory with repeated imaging of a small preform specimens after various processing times. We use these images to determine geometry and dimensions of channels between and through layers in cloth lay-up preform during CVI densification and relate these to a transport model.

  5. Selective laser densification of lithium aluminosilicate glass ceramic tapes

    NASA Astrophysics Data System (ADS)

    Zocca, Andrea; Colombo, Paolo; Günster, Jens; Mühler, Thomas; Heinrich, Jürgen G.

    2013-01-01

    Tapes, cast by blade deposition of a lithium aluminosilicate glass slurry, were sintered using a YAG-fiber laser, with the aim of finding suitable parameters for an additive manufacturing process based on layer-wise slurry deposition and selective laser densification. The influence of the laser parameters (output power and scan velocity) on the sintering was evaluated, by scanning electron microscopy and by X-ray diffraction, on the basis of the quality of the processed layer. Well densified samples could be obtained only in a small window of values for the output power and the scan velocity. The measurement of the width of a set of single scanned lines allowed also to estimate the minimum resolution of the system along the layer plane.

  6. Experimental Studies of Liquefaction and Densification of Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Partridge, Jonathan Koert

    2010-01-01

    The propellant combination that offers optimum performance is very reactive with a low average molecular weight of the resulting combustion products. Propellant combinations such as oxygen and hydrogen meet the above criteria, however, the propellants in gaseous form require large propellant tanks due to the low density of gas. Thus, rocketry employs cryogenic refrigeration to provide a more dense propellant stored as a liquid. In addition to propellant liquefaction, cryogenic refrigeration can also conserve propellant and provide propellant subcooling and propellant densification. Previous studies analyzed vapor conditioning of a cryogenic propellant, with the vapor conditioning by either a heat exchanger position in the vapor or by using the vapor in a refrigeration cycle as the working fluid. This study analyzes the effects of refrigeration heat exchanger located in the liquid of the common propellant oxidizer, liquid oxygen. This study predicted and determined the mass condensation rate and heat transfer coefficient for liquid oxygen.

  7. LIBRA: An inexpensive geodetic network densification system

    NASA Technical Reports Server (NTRS)

    Fliegel, H. F.; Gantsweg, M.; Callahan, P. S.

    1975-01-01

    A description is given of the Libra (Locations Interposed by Ranging Aircraft) system, by which geodesy and earth strain measurements can be performed rapidly and inexpensively to several hundred auxiliary points with respect to a few fundamental control points established by any other technique, such as radio interferometry or satellite ranging. This low-cost means of extending the accuracy of space age geodesy to local surveys provides speed and spatial resolution useful, for example, for earthquake hazards estimation. Libra may be combined with an existing system, Aries (Astronomical Radio Interferometric Earth Surveying) to provide a balanced system adequate to meet the geophysical needs, and applicable to conventional surveying. The basic hardware design was outlined and specifications were defined. Then need for network densification was described. The following activities required to implement the proposed Libra system are also described: hardware development, data reduction, tropospheric calibrations, schedule of development and estimated costs.

  8. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  9. Densification and shape distortion in liquid-phase sintering

    SciTech Connect

    Liu, J.; German, R.M.

    1999-12-01

    Densification and dimensional control are important aspects of liquid-phase sintering. The capillary force and the solid bonding affect both densification and shape preservation. Capillarity, which is orientated isotropically, causes uniform shrinkage and holds grains together to preserve the component shape in the early stage of sintering. On the other hand, solid bonding resists viscous flow and inhibits densification and shape distortion. The capillary force decreases with densification and approaches zero as pores are eliminated. Thus, shape retention eventually requires solid-grain bonding. The solid-grain bonding provides compact rigidity, which is represented by compact strength. Shape distortion occurs when the compact loses its strength. For every situation, there is a critical compact strength above which no shape distortion occurs. Distortion in liquid-phase sintering indicates that the compact strength passed below a critical level.

  10. Consolidation and densification methods for fibrous monolith processing

    SciTech Connect

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2006-06-20

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  11. STS propellant densification feasibility study data book

    NASA Technical Reports Server (NTRS)

    Fazah, M. M.

    1994-01-01

    The feasibility of using densification or subcooling with respect to standard temperature propellants on the Space Transportation System (STS) in order to achieve a payload gain is discussed in this report. The objective is to determine the magnitude of the payload gain and to identify any system impacts to the space shuttle on either flight systems or ground systems. Results show that a payload benefit can be obtained by subcooling the liquid hydrogen (LH2) from a nominal temperature of 36.4 R to 28.5 R and by subcooling the liquid oxygen (LO2) from a nominal temperature of 164 R to either 132.1 R or 141.4 R. When the propellants are subcooled to 28.5 R and 132.1 R for the LH2 and LO2, respectively, a maximum payload gain of 7,324 lb can be achieved, and when the propellants are subcooled to 28.5 R and 141.5 R for the LH2 and LO2, respectively, a maximum payload gain of 6,841 lb can be achieved. If the LH2 is subcooled to 28.5 R while the LH2 and LO2 remains at the nominal conditions, a maximum payload gain of 1,303 lb can be achieved.

  12. Enhanced Densification of SDC Barrier Layers

    SciTech Connect

    Hardy, John S.; Templeton, Jared W.; Lu, Zigui; Stevenson, Jeffry W.

    2011-09-12

    This technical report explores the Enhanced Densification of SCD Barrier Layers A samaria-doped ceria (SDC) barrier layer separates the lanthanum strontium cobalt ferrite (LSCF) cathode from the yttria-stabilized zirconia (YSZ) electrolyte in a solid oxide fuel cell (SOFC) to prevent the formation of electrically resistive interfacial SrZrO{sub 3} layers that arise from the reaction of Sr from the LSCF with Zr from the YSZ. However, the sintering temperature of this SDC layer must be limited to {approx}1200 C to avoid extensive interdiffusion between SDC and YSZ to form a resistive CeO{sub 2}-ZrO{sub 2} solid solution. Therefore, the conventional SDC layer is often porous and therefore not as impervious to Sr-diffusion as would be desired. In the pursuit of improved SOFC performance, efforts have been directed toward increasing the density of the SDC barrier layer without increasing the sintering temperature. The density of the SDC barrier layer can be greatly increased through small amounts of Cu-doping of the SDC powder together with increased solids loading and use of an appropriate binder system in the screen print ink. However, the resulting performance of cells with these barrier layers did not exhibit the expected increase in accordance with that achieved with the prototypical PLD SDC layer. It was determined by XRD that increased sinterability of the SDC also results in increased interdiffusivity between the SDC and YSZ, resulting in formation of a highly resistive solid solution.

  13. The densification of bio-char: Effect of pyrolysis temperature on the qualities of pellets.

    PubMed

    Hu, Qiang; Yang, Haiping; Yao, Dingding; Zhu, Danchen; Wang, Xianhua; Shao, Jingai; Chen, Hanping

    2016-01-01

    The densification of bio-chars pyrolyzed at different temperatures were investigated to elucidate the effect of temperature on the properties of bio-char pellets and determine the bonding mechanism of pellets. Optimized process conditions were obtained with 128MPa compressive pressure and 35% water addition content. Results showed that both the volume density and compressive strength of bio-char pellets initially decreased and subsequently increased, while the energy consumption increased first and then decreased, with the increase of pyrolysis temperature. The moisture adsorption of bio-char pellets was noticeably lower than raw woody shavings but had elevated than the corresponding char particles. Hydrophilic functional groups, particle size and binder were the main factors that contributed to the cementation of bio-char particles at different temperatures. The result indicated that pyrolysis of woody shavings at 550-650°C and followed by densification was suitable to form bio-char pellets for application as renewable biofuels.

  14. SIRGAS: ITRF densification in Latin America and the Caribbean

    NASA Astrophysics Data System (ADS)

    Brunini, C.; Costa, S.; Mackern, V.; Martínez, W.; Sánchez, L.; Seemüller, W.; da Silva, A.

    2009-04-01

    solution for station coordinates (i.e., coordinates for all stations are constrained to 1 m). This solution in SINEX format is submitted to IGS for the global polyhedron. 8) Combination obtained in (7) is constrained by applying NNR+NNT conditions with respect to the IGS05 stations included the SIRGAS region to provide constrained coordinates for all SIRGAS-CON (core + densification) stations. The applied IGS05 reference coordinates correspond to the weekly IGS solution for the global network, i.e., coordinates included in the igsYYPwwww.snx files. This constrained solution provides the final weekly SIRGAS-CON coordinates for practical applications. The DGFI (i.e. IGS RNAAC SIR) weekly combinations are delivered to the IGS Data Centres for combination in the global polyhedron, and made available for users as official SIRGAS products, respectively. The IBGE weekly combinations provide control and back-up. The above described analysis strategy is applied since GPS week 1495. Before (since June 1996 to August 2008), the SIRGAS-CON network was totally processed by DGFI. Until now, results show a very good agreement with previous computations; however, the present sub-networks distribution has two main disadvantages: 1) Not all SIRGAS-CON stations are included in the same number of individual solutions, i.e., they are unequally weighted in the weekly combinations, and 2) since there are not enough Local Processing Centres, the required redundancy (each station processed by at least three processing centres) is not fulfilled. Therefore, efforts are being made to install additional Local Processing Centres in Latin American countries as Argentina, Ecuador, Mexico, Peru, Uruguay, and Venezuela.

  15. Permeability during densification of viscous droplets

    NASA Astrophysics Data System (ADS)

    Wadsworth, Fabian; Vasseur, Jérémie; Llewellin, Ed; Dobson, Katherine; Schauroth, Jenny; Heap, Michael; Farquharson, Jamie; Scheu, Bettina; Kendrick, Jackie; Lavallée, Yan; von Aulock, Felix; Dingwell, Donald B.

    2016-04-01

    Fragmentation of magma can yield a transiently granular material, which can subsequently weld back to a fluid-continuum. This process results in dramatic changes in the porosity of the material, which impacts its fluid permeability. We collate published data for the porosity and permeability of volcanic and synthetic materials which have undergone this process to different amounts. By discriminating data for which good microstructural information are provided, we use simple scaling arguments to collapse the data in both the still-granular, high porosity region, and the fluid-continuum low porosity region, such that a universal description can be provided. This allows us to describe the microstructural meaning of permeability scaling, and to infer the controls on the position of this transition between dominantly granular (dispersion) and dominantly fluid-continuum materials. Fractures in coherent magmas are thought to be a primary degassing pathway in high viscosity systems. As a specific application, we consider transiently granular magma being transported through and deposited in these fractures. We finally present a physical model for the kinetics of porosity changes in arrays of viscous droplets and compare this with our experimental data. The combination of the physical model for the evolution of porosity with the scaling between porosity and permeability permits us to describe the evolution of permeability during densification. We anticipate that this will be a useful tool for predicting the longevity of degassing pathways in granular filled cracks, both in conduits and shallow lava domes, as well as during the sedimentation of exceptionally hot ignimbrites undergoing compaction and welding.

  16. Densification Kinetics and Structural Evolution During Microwave and Pressureless Sintering of 15 nm Titanium Nitride Powder

    NASA Astrophysics Data System (ADS)

    Zgalat-Lozynskyy, Ostap; Ragulya, Andrey

    2016-02-01

    Microwave sintering (MWS) of commercially available 15-nm-size nanocrystalline TiN powder was studied. Densification kinetics and grain growth mechanisms of nano-TiN were evaluated using non-isothermal heating up to 1500 °C with variable heating rates. A true nanocrystalline ceramic with ~80-nm-size grains and 94.5 % theoretical density was obtained via MWS consolidation at 1400 °C. At higher temperatures, however, an uncontrolled grain growth and a formation of bimodal microstructure were noticed. A temperature dependence of grain growth suggested grain boundary sliding as a primary mechanism of densification below 1100-1200 °C. An activation energy of nano-TiN densification under MWS varied from 26 ± 3 kJ/mol at the initial stage of sintering (900-1200 °C) to 162 ± 22 kJ/mol at higher temperatures. In addition, a relationship coupling microstructural characteristics (grain size, grain boundary) with mechanical properties of titanium nitride ceramics obtained via both microwave and pressureless sintering techniques was discussed.

  17. Effects of torrefaction and densification on switchgrass pyrolysis products

    SciTech Connect

    Yang, Zixu; Sarkar, Madhura; Kumar, Ajay; Tumuluru, Jaya Shankar; Huhnke, Raymond L.

    2014-12-01

    Abstract The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270 °C, densification, and torrefaction at 270 ºC followed by densification) were studied at three temperatures (500, 600, 700 ºC) using a pyroprobe attached to a gas chromatogram mass spectroscopy (Py-GC/MS). The torrefaction of switchgrass improved its oxygen to carbon ratio and energy content. Contents of anhydrous sugars and phenols in pyrolysis products of torrefied switchgrass were higher than those in pyrolysis products of raw switchgrass. As the torrefaction temperature increased from 230 to 270 °C, the contents of anhydrous sugars and phenols in pyrolysis products increased whereas content of guaiacols decreased. High pyrolysis temperature (600 and 700 °C as compared to 500 °C) enhanced decomposition of lignin and anhydrous sugars, leading to increase in phenols, aromatics and furans. Densification enhanced depolymerization of cellulose and hemicellulose during pyrolysis.

  18. Effects of torrefaction and densification on switchgrass pyrolysis products.

    PubMed

    Yang, Zixu; Sarkar, Madhura; Kumar, Ajay; Tumuluru, Jaya Shankar; Huhnke, Raymond L

    2014-12-01

    The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270°C, densification, and torrefaction at 270°C followed by densification) were studied at three temperatures (500, 600, 700°C) using a pyroprobe attached to a gas chromatogram mass spectroscopy (Py-GC/MS). The torrefaction of switchgrass improved its oxygen to carbon ratio and energy content. Contents of anhydrous sugars and phenols in pyrolysis products of torrefied switchgrass were higher than those in pyrolysis products of raw switchgrass. As the torrefaction temperature increased from 230 to 270°C, the contents of anhydrous sugars and phenols in pyrolysis products increased whereas content of guaiacols decreased. High pyrolysis temperature (600 and 700°C as compared to 500°C) enhanced decomposition of lignin and anhydrous sugars, leading to increase in phenols, aromatics and furans. Densification enhanced depolymerization of cellulose and hemicellulose during pyrolysis.

  19. Consolidation and densification methods for fibrous monolith processing

    DOEpatents

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2004-05-25

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered in an inert gas or nitrogen gas at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  20. Formation and densification of SiAlON materials by reaction bonding and silicothermal reduction routes

    NASA Astrophysics Data System (ADS)

    Rouquié, Yann; Jones, Mark I.

    2011-05-01

    Samples of β and O-sialon with different levels of substitution (i.e. z = 1 and 4 for β-sialon and x = 0.05 and 0.2 for O-sialon) have been synthesized by both reaction bonding and silicothermal reduction techniques in a nitrogen atmosphere. The possibility of obtaining dense sialon materials by these lower cost production methods has been investigated using a statistical design methodology. The influence of different parameters (temperature, gas pressure and additive type) on the densification and decomposition has been studied and will be discussed in this presentation.

  1. Enhanced densification under shock compression in porous silicon

    SciTech Connect

    Lane, J. Matthew; Thompson, Aidan Patrick; Vogler, Tracy

    2014-10-27

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. The mechanism driving this behavior was not completely determined. We present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials and demonstrate the associated mechanisms responsible for the effect in porous silicon. Atomistic response indicates that local shear strain in the neighborhood of collapsing pores catalyzes a local solid-solid phase transformation even when bulk pressures are below the thermodynamic phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.

  2. Enhanced densification under shock compression in porous silicon

    DOE PAGESBeta

    Lane, J. Matthew; Thompson, Aidan Patrick; Vogler, Tracy

    2014-10-27

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. The mechanism driving this behavior was not completely determined. We present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials and demonstrate the associated mechanisms responsible for the effect in porous silicon. Atomistic response indicates that local shear strain in the neighborhood of collapsing pores catalyzes a local solid-solid phase transformation even when bulk pressures are below the thermodynamicmore » phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.« less

  3. Effects of torrefaction and densification on switchgrass pyrolysis products

    DOE PAGESBeta

    Yang, Zixu; Sarkar, Madhura; Kumar, Ajay; Tumuluru, Jaya Shankar; Huhnke, Raymond L.

    2014-12-01

    Abstract The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270 °C, densification, and torrefaction at 270 ºC followed by densification) were studied at three temperatures (500, 600, 700 ºC) using a pyroprobe attached to a gas chromatogram mass spectroscopy (Py-GC/MS). The torrefaction of switchgrass improved its oxygen to carbon ratio and energy content. Contents of anhydrous sugars and phenols in pyrolysis products of torrefied switchgrass were higher than those in pyrolysis products of raw switchgrass. As the torrefaction temperature increased from 230 to 270 °C, the contents of anhydrous sugars and phenols in pyrolysis productsmore » increased whereas content of guaiacols decreased. High pyrolysis temperature (600 and 700 °C as compared to 500 °C) enhanced decomposition of lignin and anhydrous sugars, leading to increase in phenols, aromatics and furans. Densification enhanced depolymerization of cellulose and hemicellulose during pyrolysis.« less

  4. Frost Growth and Densification in Laminar Flow Over Flat Surfaces

    NASA Technical Reports Server (NTRS)

    Kandula, Max

    2011-01-01

    One-dimensional frost growth and densification in laminar flow over flat surfaces has been theoretically investigated. Improved representations of frost density and effective thermal conductivity applicable to a wide range of frost circumstances have been incorporated. The validity of the proposed model considering heat and mass diffusion in the frost layer is tested by a comparison of the predictions with data from various investigators for frost parameters including frost thickness, frost surface temperature, frost density and heat flux. The test conditions cover a range of wall temperature, air humidity ratio, air velocity, and air temperature, and the effect of these variables on the frost parameters has been exemplified. Satisfactory agreement is achieved between the model predictions and the various test data considered. The prevailing uncertainties concerning the role air velocity and air temperature on frost development have been elucidated. It is concluded that that for flat surfaces increases in air velocity have no appreciable effect on frost thickness but contribute to significant frost densification, while increase in air temperatures results in a slight increase the frost thickness and appreciable frost densification.

  5. Dynamic elastic moduli during isotropic densification of initially granular media

    NASA Astrophysics Data System (ADS)

    Vasseur, Jérémie; Wadsworth, Fabian B.; Lavallée, Yan; Dingwell, Donald B.

    2016-03-01

    The elastic properties of homogeneous, isotropic materials are well constrained. However, in heterogeneous and evolving materials, these essential properties are less well-explored. During sintering of volcanic ash particles by viscous processes as well as during compaction and cementation of sediments, microstructure and porosity undergo changes that affect bulk dynamic elastic properties. Here using a model system of glass particles as an analogue for initially granular rock-forming materials, we have determined porosity and P-wave velocity during densification. Using these results, we test models for the kinetics of densification and the resultant evolution of the elastic properties to derive a quantitative description of the coupling between the kinetics of isotropic densification and the evolving dynamic elastic moduli. We demonstrate the power of the resultant model on a wide range of data for non-coherent sediments as well as sedimentary and volcanic rocks. We propose that such constraints be viewed as an essential ingredient of time-dependent models for the deformation of evolving materials in volcanoes and sedimentary basins.

  6. Gasification performance of switchgrass pretreated with torrefaction and densification

    SciTech Connect

    Jaya Shankar Tumuluru; Various

    2014-08-01

    The purpose of this study was to investigate gasification performance of four switchgrass pretreatments (torrefaction at 230 and 270 °C, densification, and combined torrefaction and densification) and three gasification temperatures (700, 800 and 900 °C). Gasification was performed in a fixed-bed externally heated reactor with air as an oxidizing agent. Switchgrass pretreatment and gasification temperature had significant effects on gasification performance such as gas yields, syngas lower heating value (LHV), and carbon conversion and cold gas efficiencies. With an increase in the gasification temperature, yields of H2 and CO, syngas LHV, and gasifier efficiencies increased whereas CH4, CO2 and N2 yields decreased. Among all switchgrass pretreatments, gasification performance of switchgrass with combined torrefaction and densification was the best followed by that of densified, raw and torrefied switchgrass. Gasification of combined torrefied and densified switchgrass resulted in the highest yields of H2 (0.03 kg/kg biomass) and CO (0.72 kg/kg biomass), highest syngas LHV (5.08 MJ m-3), CCE (92.53%), and CGE (68.40%) at the gasification temperature of 900 °C.

  7. Densification of nanocrystalline ITO powders in fast firing: effect of specimen mass and sintering atmosphere

    SciTech Connect

    Kim, Bong-Chull; Lee, Joon-Hyung; Kim, Jeong-Joo . E-mail: jjkim@knu.ac.kr; Lee, Hee Young; Lee, Jai-Sung

    2005-02-15

    Nano-sized indium tin oxide (ITO) powders were prepared by a coprecipitation method, and the sintering characteristics in fast firing were examined. The mass of the specimen, sintering atmosphere and sintering temperature varied. Oxygen atmosphere promoted the densification in normal rate sintering, while oxygen inhibited the densification in fast firing. Fast firing severely retarded densification as the mass of the specimen and the sintering temperature increased. This was explained by differential densification, which could easily occur in conditions with a high densification rate and a high thermal gradient in the specimen, where the outer region of the specimen densifies much faster than the center. Once the highly densified outer skeleton is formed, the inside of the specimen is difficult to densify because the outer skeleton geometrically constrains densification.

  8. Permanent densification of compressed silica glass: a Raman-density calibration curve.

    PubMed

    Deschamps, T; Kassir-Bodon, A; Sonneville, C; Margueritat, J; Martinet, C; de Ligny, D; Mermet, A; Champagnon, B

    2013-01-16

    Raman scattering experiments have been carried out to study persistent densification in SiO(2) glass following hydrostatic compression at room temperature. A new relationship linking selective Raman parameters to the degree of densification in the glass has been developed here. This approach will allow quantification of the residual densification in silica following microindentation experiments, with the goal being the development of a constitutive law for amorphous silica.

  9. Vibrational dynamics of permanently densified GeO{sub 2} glasses: Densification-induced changes in the boson peak

    SciTech Connect

    Orsingher, L.; Fontana, A.; Gilioli, E.; Carini, G. Jr.; Carini, G.; Tripodo, G.; Unruh, T.; Buchenau, U.

    2010-03-28

    Vitreous GeO{sub 2}, one of the main prototypes of strong glasses, was densified at several pressures up to 6 GPa, achieving more than 20% of densification. The density dependence of the vibrational density of states and of the low temperature properties of these glasses was investigated by means of inelastic neutron scattering and calorimetric measurements. With increasing density, both the boson peak and the bump in c{sub p}/T{sup 3} versus T plot exhibit variations which are stronger than the elastic medium expectation. If one reduces the measured spectra to a common master curve, one finds that this is only possible for the densified samples; the first densification step has an additional effect, similar to other cases in the literature. Nevertheless, the existence of a master curve for the three densified samples proves that the total number of excess modes remains constant on further densification. The experimental data are discussed in the framework of different theoretical models.

  10. Poisson's Ratio and the Densification of Glass under High Pressure

    SciTech Connect

    Rouxel, T.; Ji, H.; Hammouda, T.; Moreac, A.

    2008-06-06

    Because of a relatively low atomic packing density, (C{sub g}) glasses experience significant densification under high hydrostatic pressure. Poisson's ratio ({nu}) is correlated to C{sub g} and typically varies from 0.15 for glasses with low C{sub g} such as amorphous silica to 0.38 for close-packed atomic networks such as in bulk metallic glasses. Pressure experiments were conducted up to 25 GPa at 293 K on silica, soda-lime-silica, chalcogenide, and bulk metallic glasses. We show from these high-pressure data that there is a direct correlation between {nu} and the maximum post-decompression density change.

  11. The prospects for urban densification: a place-based study

    NASA Astrophysics Data System (ADS)

    Schmidt-Thomé, Kaisa; Haybatollahi, Mohammad; Kyttä, Marketta; Korpi, Jari

    2013-06-01

    Study of the environmental outcomes of urban densification is a highly context-dependent task. Our study shows that collecting and processing place-based survey data by means of the softGIS method is clearly helpful here. With the map-based internet questionnaire each response remains connected to both the physical environment and the everyday life of the respondent. In our study of the Kuninkaankolmio area (located in the Helsinki metropolitan region) the survey data were combined with urban density variables calculated from register-based data on the existing built environment. The regression analysis indicated that the participants in the survey preferred the same density factors for their future residence as they enjoyed in their current neighbourhood. In the second analysis we related the densities of planned infill developments with the interest respondents had shown in these projects. The results show that new and even quite dense infill developments have been found to be rather attractive, with them often being viewed as interesting supplements to the current urban texture. These findings contribute to the ongoing scientific discussion on the feasibility of densification measures and encourage the Kuninkaankolmio planners to proceed, albeit carefully, with the planned infill developments.

  12. Volcanic sintering: Timescales of viscous densification and strength recovery

    PubMed Central

    Vasseur, Jérémie; Wadsworth, Fabian B; Lavallée, Yan; Hess, Kai-Uwe; Dingwell, Donald B

    2013-01-01

    [1] Sintering and densification are ubiquitous processes influencing the emplacement of both effusive and explosive products of volcanic eruptions. Here we sinter ash-size fragments of a synthetic National Institute of Standards and Technology viscosity standard glass at temperatures at which the resultant melt has a viscosity of ∼108–109 Pa.s at 1bar to assess sintering dynamics under near-surface volcanic conditions. We track the strength recovery via uniaxial compressive tests. We observe that volcanic ash sintering is dominantly time dependent, temperature dependent, and grain size dependent and may thus be interpreted to be controlled by melt viscosity and surface tension. Sintering evolves from particle agglutination to viscous pore collapse and is accompanied by a reduction in connected porosity and an increase in isolated pores. Sintering and densification result in a nonlinear increase in strength. Micromechanical modeling shows that the pore-emanated crack model explains the strength of porous lava as a function of pore fraction and size. PMID:25821262

  13. Recent Advances and Applications in Cryogenic Propellant Densification Technology

    NASA Technical Reports Server (NTRS)

    Tomsik, Thomas M.

    2000-01-01

    This purpose of this paper is to review several historical cryogenic test programs that were conducted at the NASA Glenn Research Center (GRC), Cleveland, Ohio over the past fifty years. More recently these technology programs were intended to study new and improved denser forms of liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic rocket fuels. Of particular interest are subcooled cryogenic propellants. This is due to the fact that they have a significantly higher density (eg. triple-point hydrogen, slush etc.), a lower vapor pressure and improved cooling capacity over the normal boiling point cryogen. This paper, which is intended to be a historical technology overview, will trace the past and recent development and testing of small and large-scale propellant densification production systems. Densifier units in the current GRC fuels program, were designed and are capable of processing subcooled LH2 and L02 propellant at the X33 Reusable Launch Vehicle (RLV) scale. One final objective of this technical briefing is to discuss some of the potential benefits and application which propellant densification technology may offer the industrial cryogenics production and end-user community. Density enhancements to cryogenic propellants (LH2, LO2, CH4) in rocket propulsion and aerospace application have provided the opportunity to either increase performance of existing launch vehicles or to reduce the overall size, mass and cost of a new vehicle system.

  14. Hydrogen Confinement in Carbon Nanopores: Extreme Densification at Ambient Temperature

    SciTech Connect

    Gallego, Nidia C; He, Lilin; Saha, Dipendu; Contescu, Cristian I; Melnichenko, Yuri B

    2011-01-01

    In-situ small angle neutron scattering (SANS) studies of hydrogen confined in small pores of polyfurfuryl alcohol-derived activated carbon (PFAC) at room-temperature provided for the first time its phase behavior in equilibrium with external H2 at pressures up to 200 bar. The data was used to evaluate the density of the adsorbed fluid, which appears to be a function of both pore size and pressure, and approaches the liquid hydrogen density in narrow nanopores at 200 bar. The surface-molecule interactions responsible for densification of hydrogen within the pores create internal pressures which exceed by a factor of up to ~ 60 the external gas pressures, confirming the benefits of adsorptive over compressive storage. These results can be utilized to guide the development of new carbon adsorbents tailored for maximum hydrogen storage capacities at near ambient temperatures.

  15. On the Densification Behavior of (0.2, 0.5, and 1 Wt Pct) CNT-YSZ Ceramic Composites Processed via Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Karanam, Abhinav; Bichler, Lukas; Fong, Randy

    2015-08-01

    Yttria-Stabilized Zirconia (YSZ) is a promising thermal insulating ceramic for high temperature applications due to its stability and chemical inertness. As was demonstrated with other technical ceramics ( e.g., Alumina), addition of Single-Wall Carbon Nanotubes (CNTs) to a ceramic matrix may significantly enhance its mechanical properties. In this work, 8 mol pct YSZ with 0.2, 0.5, and 1 wt pct CNT composites were fabricated via the spark plasma sintering process. The densification, Vicker's microhardness, specific gravity, and microstructure evolution of the composites were investigated. The results suggest that the addition of CNTs to YSZ hindered densification and grain growth during SPS processing leading to inhomogeneous grain size distribution. However, the CNTs had a profound impact on the hardness of the composite ceramics, with an increase from 697 HV (YSZ) to 1195 HV (1 wt pctCNT-YSZ).

  16. Densification effects on the Boson peak in vitreous silica: A molecular-dynamics study

    NASA Astrophysics Data System (ADS)

    Jund, P.; Jullien, R.

    2000-08-01

    We perform classical molecular-dynamics simulation to study the effect of densification on the vibrational spectrum of a model silica glass. We concentrate this study on the so-called Boson peak and compare our results, obtained from a direct diagonalization of the dynamical matrix, with experimental Raman data. We show that, upon densification, the position of the Boson peak shifts towards higher frequencies while its magnitude decreases which is in agreement with a recent experimental study.

  17. Full Densification of Molybdenum Powders Using Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Mouawad, B.; Soueidan, M.; Fabrègue, D.; Buttay, C.; Bley, V.; Allard, B.; Morel, H.

    2012-09-01

    Pure molybdenum powder was sintered using spark plasma sintering (SPS) under various temperatures and holding times, under a pressure of 77 MPa and a heating rate at 700 K/min (700 °C/min). After sintering, a carbide layer was observed at the surface. The carbide layer thickness, the relative density of the sample as well as the microhardness, and the grain size of Mo were measured. The carbide thickness depends on time and temperature, and it was found that the carbide layer grows in a parabolic manner, with the activation energy of carbon diffusion in Mo being equal to 34 Kcal/mol. The densification of Mo is controlled mainly by the sintering temperature and the holding time. The molybdenum powder was successfully consolidated by SPS in short times. A relative density of 100 pct is achieved at a sintering temperature of 2123.15 K (1850 °C) and a holding time of 30 minutes. It was shown that the hardness decreases slightly with temperature and time. It should be related to the increase in grain size with the sintering temperature and time.

  18. Full Densification of Molybdenum Powders Using Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Mouawad, B.; Soueidan, M.; Fabrègue, D.; Buttay, C.; Bley, V.; Allard, B.; Morel, H.

    2012-05-01

    Pure molybdenum powder was sintered using spark plasma sintering (SPS) under various temperatures and holding times, under a pressure of 77 MPa and a heating rate at 700 K/min (700 °C/min). After sintering, a carbide layer was observed at the surface. The carbide layer thickness, the relative density of the sample as well as the microhardness, and the grain size of Mo were measured. The carbide thickness depends on time and temperature, and it was found that the carbide layer grows in a parabolic manner, with the activation energy of carbon diffusion in Mo being equal to 34 Kcal/mol. The densification of Mo is controlled mainly by the sintering temperature and the holding time. The molybdenum powder was successfully consolidated by SPS in short times. A relative density of 100 pct is achieved at a sintering temperature of 2123.15 K (1850 °C) and a holding time of 30 minutes. It was shown that the hardness decreases slightly with temperature and time. It should be related to the increase in grain size with the sintering temperature and time.

  19. On the self-damping nature of densification in photonic sintering of nanoparticles

    NASA Astrophysics Data System (ADS)

    MacNeill, William; Choi, Chang-Ho; Chang, Chih-Hung; Malhotra, Rajiv

    2015-10-01

    Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sintering of silver nanoparticle inks, as a function of nanoparticle size. It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles. Further, high densification can be achieved even without nanoparticle melting. Electromagnetic Finite Element Analysis of photonic heating is coupled to an analytical sintering model, to examine the role of interparticle neck growth in photonic sintering. It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached. By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models. Further, this model is used to uncover the reason behind the experimentally observed increase in densification with increasing weight ratio of smaller to larger nanoparticles.

  20. On the self-damping nature of densification in photonic sintering of nanoparticles

    PubMed Central

    MacNeill, William; Choi, Chang-Ho; Chang, Chih-Hung; Malhotra, Rajiv

    2015-01-01

    Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sintering of silver nanoparticle inks, as a function of nanoparticle size. It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles. Further, high densification can be achieved even without nanoparticle melting. Electromagnetic Finite Element Analysis of photonic heating is coupled to an analytical sintering model, to examine the role of interparticle neck growth in photonic sintering. It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached. By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models. Further, this model is used to uncover the reason behind the experimentally observed increase in densification with increasing weight ratio of smaller to larger nanoparticles. PMID:26443492

  1. Real-time assessment of granule densification in high shear wet granulation and application to scale-up of a placebo and a brivanib alaninate formulation.

    PubMed

    Narang, Ajit S; Sheverev, Valery A; Stepaniuk, Vadim; Badawy, Sherif; Stevens, Tim; Macias, Kevin; Wolf, Avi; Pandey, Preetanshu; Bindra, Dilbir; Varia, Sailesh

    2015-03-01

    Real-time monitoring and control of high shear wet granulation (HSWG) using process analytical technologies is crucial to process design, scale-up, and reproducible manufacture. Although significant progress has been made in real-time measurement of granule size distribution using focused beam reflectance measurement (FBRM), real-time in-line assessment of granule densification remains challenging. In this study, a drag force flow (DFF) sensor was developed and used to probe wet mass consistency in real-time. In addition, responses from FBRM and DFF sensors were compared to assess complementarity of information on granulation progress from the two probes. A placebo and a brivanib alaninate formulation were granulated with different concentrations of binder or water, respectively, while measuring granule size growth, densification, and DFF sensor response. The DFF sensor was able to quantitatively characterize with high resolution a response of wet mass consistency distinct from granule size distribution. The wet mass consistency parameter correlated well with granule densification, which was shown as a critical material attribute that correlated with tablet dissolution. In addition, application of DFF sensor to scale-up of granulation was demonstrated. These results showed the value of wet mass consistency measurement using DFF for WG monitoring and control. PMID:25470221

  2. Real-time assessment of granule densification in high shear wet granulation and application to scale-up of a placebo and a brivanib alaninate formulation.

    PubMed

    Narang, Ajit S; Sheverev, Valery A; Stepaniuk, Vadim; Badawy, Sherif; Stevens, Tim; Macias, Kevin; Wolf, Avi; Pandey, Preetanshu; Bindra, Dilbir; Varia, Sailesh

    2015-03-01

    Real-time monitoring and control of high shear wet granulation (HSWG) using process analytical technologies is crucial to process design, scale-up, and reproducible manufacture. Although significant progress has been made in real-time measurement of granule size distribution using focused beam reflectance measurement (FBRM), real-time in-line assessment of granule densification remains challenging. In this study, a drag force flow (DFF) sensor was developed and used to probe wet mass consistency in real-time. In addition, responses from FBRM and DFF sensors were compared to assess complementarity of information on granulation progress from the two probes. A placebo and a brivanib alaninate formulation were granulated with different concentrations of binder or water, respectively, while measuring granule size growth, densification, and DFF sensor response. The DFF sensor was able to quantitatively characterize with high resolution a response of wet mass consistency distinct from granule size distribution. The wet mass consistency parameter correlated well with granule densification, which was shown as a critical material attribute that correlated with tablet dissolution. In addition, application of DFF sensor to scale-up of granulation was demonstrated. These results showed the value of wet mass consistency measurement using DFF for WG monitoring and control.

  3. Effect of aspect ratio and liquid-phase content on densification of alumina-silicon carbide whisker composites

    SciTech Connect

    Tiegs, T.N.; Dillard, D.M. . Metals and Ceramics Div.)

    1990-05-01

    This paper reports that densification of alumina-SiC whisker composites by pressureless sintering is inhibited as a result of whisker interference with particle rearrangement and composite shrinkage. Reduction of the aspect ratio improves densification by improving particle/whisker packing for increased green densities and enhances the ability of the whiskers to rearrange themselves during sintering. Increasing the amount of liquid phases present during sintering also improves densification by aiding whisker rearrangement.

  4. Effect of Heating Rate on the Pressureless Sintering Densification of a Nickel-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Levasseur, David; Brochu, Mathieu

    2016-05-01

    Pressureless sintering of Inconel 718 has important technological applications for the densification of metal injection molding or additive manufacturing of parts with powder/binder systems. The effect of heating rates ranging from 15 to 200 K/minute on the sintering behavior of fine (-325 mesh) Inconel 718 powders was studied using the master sintering curve (MSC) concept. A pressureless pulsed electric current sintering setup was used to heat samples. The temperature at the onset of sintering increased as the heating rate increased. The formation of a supersolidus liquid fraction was shifted toward higher temperatures for increased heating rates. The apparent activation energy of sintering was obtained by least squares fitting of the sintering data to the MSC and was in good agreement with the lattice diffusion activation energy of the alloying elements present in Inconel 718. The MSC followed different kinetics for low heating rates (≤50 K/minute) and high heating rates (≥75 K/minute), and these differences were related to liquation kinetics.

  5. Effect of initial particle size and densification on AFEX-pretreated biomass for ethanol production.

    PubMed

    Rijal, Binod; Biersbach, Gwen; Gibbons, William R; Pryor, Scott W

    2014-09-01

    Switchgrass (SG), corn stover (CS), and prairie cordgrass (PCG) pretreated with ammonia fiber expansion (AFEX) were densified using a novel low-temperature, low-pressure densification method. Simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) were performed with loose and densified AFEX-treated biomass to determine the effect of post-AFEX densification. Biomass particle size reduction before pretreatment increased 144-h SSF ethanol yields from densified material by 8-9 % although no significant differences were seen in the first 72 h. Grinding material after densification had no impact on final ethanol yields but increased production rates in the first 24-48 h. Low-pressure, post-AFEX densification had no adverse effects on SSF ethanol yields from SG or CS but reduced yields from densified PCG by 16 %. Glucose concentrations after hydrolysis (SHF) showed similar trends. Ethanol yields after SHF, however, showed that densification had no significant impact on CS or PCG but reduced final ethanol yields from SG.

  6. A Technical Review on Biomass Processing: Densification, Preprocessing, Modeling and Optimization

    SciTech Connect

    Jaya Shankar Tumuluru; Christopher T. Wright

    2010-06-01

    It is now a well-acclaimed fact that burning fossil fuels and deforestation are major contributors to climate change. Biomass from plants can serve as an alternative renewable and carbon-neutral raw material for the production of bioenergy. Low densities of 40–60 kg/m3 for lignocellulosic and 200–400 kg/m3 for woody biomass limits their application for energy purposes. Prior to use in energy applications these materials need to be densified. The densified biomass can have bulk densities over 10 times the raw material helping to significantly reduce technical limitations associated with storage, loading and transportation. Pelleting, briquetting, or extrusion processing are commonly used methods for densification. The aim of the present research is to develop a comprehensive review of biomass processing that includes densification, preprocessing, modeling and optimization. The specific objective include carrying out a technical review on (a) mechanisms of particle bonding during densification; (b) methods of densification including extrusion, briquetting, pelleting, and agglomeration; (c) effects of process and feedstock variables and biomass biochemical composition on the densification (d) effects of preprocessing such as grinding, preheating, steam explosion, and torrefaction on biomass quality and binding characteristics; (e) models for understanding the compression characteristics; and (f) procedures for response surface modeling and optimization.

  7. Effects of enzyme loading, densification, and storage on AFEX-pretreated biomass for ethanol production.

    PubMed

    Biersbach, Gwen; Rijal, Binod; Pryor, Scott W; Gibbons, William R

    2015-12-01

    Corn stover, switchgrass, and prairie cordgrass were treated with an ammonia fiber expansion (AFEX) process and a novel densification method (ComPAKco). Separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) were used to evaluate impacts of densification. ComPAKco densification is characterized by low-temperature and low-energy requirements, resulting in compacted biomass briquettes (CBB) 1-2 cm square, with a bulk density of 380-460 kg/m(3). Feedstocks were evaluated before and following AFEX pretreatment, after densification, and after storage. Two enzyme doses were tested. The low rate used 5 filter paper units (FPU) of Spezyme CP (cellulase) and 21.3 cellobiase units (CBU) of Novozyme 188 (aka NS50010 [β-glucosidase]) per gram of glucan. The high dosage rate was three times higher and resulted in 40-56 % and 33-82 % higher ethanol yields with SHF and SSF, respectively. Trials revealed no adverse effect on ethanol yield following densification or 6-month storage of densified, AFEX-pretreated feedstocks.

  8. Application of powder densification models to the consolidation processing of composites

    NASA Technical Reports Server (NTRS)

    Wadley, H. N. G.; Elzey, D. M.

    1991-01-01

    Unidirectional fiber reinforced metal matrix composite tapes (containing a single layer of parallel fibers) can now be produced by plasma deposition. These tapes can be stacked and subjected to a thermomechanical treatment that results in a fully dense near net shape component. The mechanisms by which this consolidation step occurs are explored, and models to predict the effect of different thermomechanical conditions (during consolidation) upon the kinetics of densification are developed. The approach is based upon a methodology developed by Ashby and others for the simpler problem of HIP of spherical powders. The complex problem is devided into six, much simpler, subproblems, and then their predicted contributions are added to densification. The initial problem decomposition is to treat the two extreme geometries encountered (contact deformation occurring between foils and shrinkage of isolated, internal pores). Deformation of these two geometries is modelled for plastic, power law creep and diffusional flow. The results are reported in the form of a densification map.

  9. Garnet-forming reactions in felsic orthogneiss: Implications for densification and strengthening of the lower continental crust

    NASA Astrophysics Data System (ADS)

    Williams, M. L.; Dumond, G.; Mahan, K.; Regan, S.; Holland, M.

    2014-11-01

    Growth of garnet and pyroxene in orthogneiss from the Athabasca granulite terrane (AGT), northern Saskatchewan, provides a model for progressive densification and strengthening of the lower continental crust with implications for the recycling and long-term evolution of continental crust. Two distinct assemblages and textures are preserved in granitic and granodioritic gneiss. Low-strain orthogneiss displays igneous textures and assemblages of Opx+Kfs+Pl+Mag+Qz (± Bt, Hbl, Ilm). High-strain, dynamically recrystallized tectonites have additional garnet, clinopyroxene, and a more Na-rich plagioclase, along with relict orthopyroxene. The reaction (Opx+Ca-rich Pl=Grt+Cpx+Na-rich Pl+Qz) is informally called the “Mary reaction” after documented occurrences in the Mary granitoid batholith. The reaction represents the transition from medium-pressure to high-pressure granulite (Green and Ringwood, 1967), but reaction progress was achieved in these deep crustal rocks along an isobaric cooling path at ca. 1 GPa (35-40 km-depth). Ambient P-T conditions were well within the product (low-T-side) stability field. The abundance of the product assemblage (Grt+Cpx+Na-rich Pl) increases with deformation. Metastable igneous assemblages are widely preserved in low-strain samples. With increasing strain, garnet occurs within recrystallized mantles of plagioclase porphyroclasts, and clinopyroxene occurs in the deformed tails of orthopyroxene crystals. Deformation is interpreted to aid in the breakdown of plagioclase and/or the nucleation of garnet and clinopyroxene. Garnet and pyroxene modes have been observed to exceed 10 vol% in the AGT, but larger amounts are possible because Ca-rich plagioclase and orthopyroxene remnants are widely preserved. Densities increase from ca. 2.6 to ca. 3.0 g/cm and modeled P-wave velocities approach 7.0 km/s in felsic rocks. Densities in mafic rocks approach 3.4 cm. The reaction occurred at least twice in the AGT, 2.6 and 1.9 Ga, and may have

  10. Effects of thermo-hygro-mechanical densification on the surface characteristics of trembling aspen and hybrid poplar wood veneers

    NASA Astrophysics Data System (ADS)

    Diouf, Papa Niokhor; Stevanovic, Tatjana; Cloutier, Alain; Fang, Chang-Hua; Blanchet, Pierre; Koubaa, Ahmed; Mariotti, Nicolas

    2011-02-01

    The effect of thermo-hygro-mechanical (THM) densification temperature on the surface color, roughness, wettability, and chemical composition of trembling aspen (Populus tremuloides) and hybrid poplar (Populus maximowiczii × P. balsamifera) veneers was investigated. Veneers were subjected to four THM densification temperatures (160 °C, 180 °C, 200 °C, and 220 °C). Veneer color darkened with increasing THM densification temperature. Surface roughness decreased between 160 °C and 200 °C. Wettability decreased after THM densification, but no significant difference was found between treated specimens. ATR-FTIR and XPS results confirmed that THM densification caused major chemical changes in veneer surfaces, and more pronounced at temperatures higher than 160 °C.

  11. Performance Tests of a Liquid Hydrogen Propellant Densification Ground System for the X33/RLV

    NASA Technical Reports Server (NTRS)

    Tomsik, Thomas M.

    1997-01-01

    A concept for improving the performance of propulsion systems in expendable and single-stage-to-orbit (SSTO) launch vehicles much like the X33/RLV has been identified. The approach is to utilize densified cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants to fuel the propulsion stage. The primary benefit for using this relatively high specific impulse densified propellant mixture is the subsequent reduction of the launch vehicle gross lift-off weight. Production of densified propellants however requires specialized equipment to actively subcool both the liquid oxygen and liquid hydrogen to temperatures below their normal boiling point. A propellant densification unit based on an external thermodynamic vent principle which operates at subatmospheric pressure and supercold temperatures provides a means for the LH2 and LOX densification process to occur. To demonstrate the production concept for the densification of the liquid hydrogen propellant, a system comprised of a multistage gaseous hydrogen compressor, LH2 recirculation pumps and a cryogenic LH2 heat exchanger was designed, built and tested at the NASA Lewis Research Center (LeRC). This paper presents the design configuration of the LH2 propellant densification production hardware, analytical details and results of performance testing conducted with the hydrogen densifier Ground Support Equipment (GSE).

  12. Bond-breaking mechanism of vitreous silica densification by IR femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Shcheblanov, Nikita S.; Povarnitsyn, Mikhail E.

    2016-04-01

    The densification of the vitreous silica (v-SiO2) due to laser irradiation appears reasonable to cause the change in refractive index. In this letter, the v-SiO2 densification under IR femtosecond laser irradiation is studied within molecular-dynamics simulation. The single- and multi-pulse interactions are explored numerically with an account of the bond-breaking mechanism. By analyzing the network at nanoscale, the nature of v-SiO2 densification is assigned to the reduction of major ring fractions of six- and seven-membered rings to minor fractions of three- and four-membered rings (related to D 2 and D 1 Raman signatures, respectively). The athermal behavior of v-SiO2 densification is disclosed at different degrees of ionization for both the single- and multi-pulse cases at sub-threshold regimes. The good agreement between calculated and measured D2 defect line and Si-O-Si angle changes argues in favor of the found mechanism.

  13. The Influence of Simulated Home and Neighbourhood Densification on Perceived Liveability

    ERIC Educational Resources Information Center

    Thomas, J. A.; Walton, D.; Lamb, S.

    2011-01-01

    This study experimentally manipulated neighbourhood density and home location to reveal the effect of these changes on perceived liveability. Two hypothetical scenarios were provided to 106 households using a Computer-Aided Personal Interview (CAPI). The first scenario examined a densification of the participant's current property, and the second…

  14. The CEGRN 2011 Campaign and the densification of ETRF2000 in Central Europe

    NASA Astrophysics Data System (ADS)

    Caporali, A.; Barlik, M.; Becker, M.; Gerhatova, L.; Grenerczy, G.; Hefty, J.; Krauss, A.; Legovini, P.; Medac, D.; Milev, G.; Mojzes, M.; Mulic, M.; Odalovic, O.; Rus, T.; Simek, J.; Sledzinski, J.; Stangl, G.; Stopar, B.; Vespe, F.; Virag, G.

    2012-04-01

    The CEGRN 2011 Campaign took place from 20 to 25 June 2011. It was a coordinated effort of 14 Central European Countries: Austria, Bosnia Herzegovina, Bulgaria, Croatia, Czech Republic, Germany, Hungary, Italy, Poland, Rumania, Serbia, Slovakia, Slovenia and Ukraine, with the involvement of some 85 stations. Data processing with state of the art software, and IGS08 orbits and antenna models according to the EPN standards is being completed by independent Analysis Centers in Austria, Hungary, Italy and Slovakia, with the Center in Graz acting as a Combination Center. The paper presents the results of the analysis and of the multiyear combination, with time series spanning a timeline of up to 17 years (1994-2011). Since all data up to and including the 2009 Campaign have been re-analysed with the reprocessed orbits and IGS05 antenna models, the derived velocity field represents a particularly valid example of evolution of the ITRF reference frame in Central Europe. The addition of the 2011 data set, based on IGS08, is not obvious. In a first step the solution, inclusive of the 2011 campaign, can be aligned to the EPN (European Permanent Network of EUREF) cumulative solution in ITRF2005 and can be transformed into the ETRF2000 frame. In a second step, the CEGRN campaigns are planned to be reprocessed with the IGS08 antenna models, provided the IGS and EPN reprocessing solutions (REPRO2) are available for the orbits. Once completed, a densification of the European regional velocity field will become available for both geodynamic studies and widespread dissemination of the ETRS89 standard of coordinates, in compliance with the EU Directive INSPIRE.

  15. Magnetic properties and densification of Manganese-Zinc soft ferrites (Mn 1-xZn xFe 2O 4) doped with low melting point oxides

    NASA Astrophysics Data System (ADS)

    Shokrollahi, H.

    Mn-Zn ferrites have high electrical resistivity, low power loss and high initial permeability up to several MHz range. Oxide additives can greatly affect the magnetic properties of these ferrites. The effects of the additives on the sintering behaviour and magnetic properties of Mn-Zn ferrites are different. Some low melting point additives such as Bi 2O 3 enhance the sintering by forming a liquid phase in the ferrites. The additive V 2O 5 enhances the sintering by increasing bulk diffusion due to the increased vacancy concentration which is accompanied by the solubility of V 5+ in the ferrites. Some additives are cations that are soluble in the host lattice and enter regular positions on the tetrahedral or octahedral sites. This paper investigates the effect of several low melting point oxides on the magnetic properties, microstructure and densification of Mn-Zn soft ferrites.

  16. Densification and strain hardening of a metallic glass under tension at room temperature.

    PubMed

    Wang, Z T; Pan, J; Li, Y; Schuh, C A

    2013-09-27

    The deformation of metallic glasses involves two competing processes: a disordering process involving dilatation, free volume accumulation, and softening, and a relaxation process involving diffusional ordering and densification. For metallic glasses at room temperature and under uniaxial loading, disordering usually dominates, and the glass can fail catastrophically as the softening process runs away in a localized mode. Here we demonstrate conditions where the opposite, unexpected, situation occurs: the densifying process dominates, resulting in stable plastic deformation and work hardening at room temperature. We report densification and hardening during deformation in a Zr-based glass under multiaxial loading, in a notched tensile geometry. The effect is driven by stress-enhanced diffusional relaxation, and is attended by a reduction in exothermic heat and hardening signatures similar to those observed in the classical thermal relaxation of glasses. The result is significant, stable, plastic, extensional flow in metallic glasses, which suggest a possibility of designing tough glasses based on their flow properties.

  17. The effect of powder sintering method on the densification and microstructure of pewter alloys

    NASA Astrophysics Data System (ADS)

    Firdaus Ariff, Tasnim; Gabbitas, Brian; Zhang, Deliang

    2009-08-01

    Pewter alloys made from tin, copper and antimony powders were sintered using microwave and conventional vacuum sintering. Three different compositions of the pewter alloy were used; 91Sn6Cu3Sb, 94Sn4Cu2Sb and 97Sn2Cu1Sb. The effect of densification and microstructure of the pewter alloys from varying sintering time and sintering mode were examined and compared. Samples were compacted at 40kN and sintered at 220°C. Samples in the conventional furnace were sintered 60 minutes and 120 minutes, while samples in the microwave furnace were sintered for 15 and 30 minutes. Samples sintered at longer sintering times resulted in higher density for both sintering methods. Microwave sintering produced samples with slightly smaller grain size than the conventionally sintered samples resulting in a better densification. There were no new phases formed from the sintering of pewter alloy.

  18. Silicon nitride-aluminum oxide solid solution (SiAION) formation and densification by pressure sintering

    NASA Technical Reports Server (NTRS)

    Yeh, H. C.; Sanders, W. A.; Fiyalko, J. L.

    1975-01-01

    Stirred-ball-mill-blended Si3N4 and Al2O3 powders were pressure sintered in order to investigate the mechanism of solid solution formation and densification in the Si3N4-Al2O3 system. Powder blends with Si3N4:Al2O3 mole ratios of 4:1, 3:2, and 2:3 were pressure sintered at 27.6-MN/sq m pressure at temperatures to 17000 C (3090 F). The compaction behavior of the powder blends during pressure sintering was determined by observing the density of the powder compact as a function of temperature and time starting from room temperature. This information, combined with the results of X-ray diffraction and metallographic analyses regarding solutioning and phase transformation phenomena in the Si3N4-Al2O3 system, was used to describe the densification behavior.

  19. ELECTROKINETIC DENSIFICATION OF COAL FINES IN WASTE PONDS

    SciTech Connect

    E. James Davis

    1999-12-18

    The objective of this research was to demonstrate that electrokinetics can be used to remove colloidal coal and mineral particles from coal-washing ponds and lakes without the addition of chemical additives such as salts and polymeric flocculants. The specific objectives were: Design and develop a scaleable electrophoresis apparatus to clarify suspensions of colloidal coal and clay particles; Demonstrate the separation process using polluted waste water from the coal-washing facilities at the coal-fired power plants in Centralia, WA; Develop a mathematical model of the process to predict the rate of clarification and the suspension electrical properties needed for scale up.

  20. Enhancing the tensile properties of continuous millimeter-scale carbon nanotube fibers by densification.

    PubMed

    Hill, Frances A; Havel, Timothy F; Hart, A John; Livermore, Carol

    2013-08-14

    This work presents a study of the tensile mechanical properties of millimeter-long fibers comprising carbon nanotubes (CNTs). These CNT fibers are made of aligned, loosely packed parallel networks of CNTs that are grown in and harvested from CNT forests without drawing or spinning. Unlike typical CNT yarn, the present fibers contain a large fraction of CNTs that span the fibers' entire gauge length. The fibers are densified after growth and network formation to study how increasing the degree of interaction among CNTs in a network by various methods influences and limits the mechanical behavior of macroscopic CNT materials, particularly for the case in which the continuity of a large fraction of CNTs across the gauge length prevents failure purely by slip. Densification is carried out using various combinations of capillary-driven densification, mechanical pressure, and twisting. All methods of densification increase the fiber density and modify the nanoscale order of the CNTs. The highest strength and stiffness values (1.8 and 88.7 N tex(-1), respectively) are observed for capillary-densified fibers, whereas the highest toughness values (94 J g(-1)) and maximum reversible energy density (1.35 kJ kg(-1) or 677 kJ m(-3)) are observed for fibers densified by mechanical pressure. The results suggest that the path to higher performance CNT materials may lie not only in the use of continuous and long CNTs but also in controlling their density and nanoscale ordering through modification of the as-grown networks, such as by capillary-driven densification. PMID:23876225

  1. Influence of Chemical Composition Variations on Densification During the Sintering of MOX Materials

    NASA Astrophysics Data System (ADS)

    Vaudez, S.; Marlot, C.; Lechelle, J.

    2016-06-01

    The mixed uranium-plutonium oxide (MOX) fabrication process is based on the preparation of UO2 and PuO2 powders. The mixture is pelletized before being sintered at 1973 K (1700 °C) in a reducing atmosphere of Ar/4pctH2/H2O. This paper shows how the densification of MOX fuel is affected during sintering by the moisture content of the gas, the plutonium content of the fuel, and the carbon impurity content in the raw materials. MOX densification can be monitored through dilatometric measurements and gas releases can be continuously analyzed during sintering in terms of their quantity and quality. Variations in the oxygen content in the fuel can be continuously recorded by coupling the dilatometer furnace with an oxygen measurement at the gas outlet. Any carbon-bearing species released, such as CO, can be also linked to densification phenomena when a gas chromatograph is installed at the outlet of the dilatometer. Recommendations on the choice of sintering atmosphere that best optimizes the fuel characteristics have been given on the basis of the results reported in this paper.

  2. Densification Process of OH Controlled Hydroxyapatite Ceramics by Spark Plasma Sintering

    SciTech Connect

    Kawagoe, D.; Koga, Y.; Ishida, E. H.; Ioku, K.

    2006-05-15

    Calcium hydroxyapatite, Ca10(PO4)6(OH)2:HA, is the inorganic principle component of natural bones and teeth. It has been already suggested that the amount of OH ion in the crystal structure of HA is closely related to the biocompatibility. The amount of OH ion in current HA, however, has not been controlled. In order to prepare more functional HA ceramics, the amount of OH ion must be controlled. In this study, HA ceramics with different OH amount were prepared from fine HA crystals by spark plasma sintering (SPS). In order to reveal the ideal sintering conditions for preparation of transparent ceramics, densification process on SPS was investigated. The samples were pressed uniaxialy under 60 MPa, and then they were heated by SPS at 800 deg. C, 900 deg. C and 1000 deg. C for 10 min with the heating rate of 25 deg. C{center_dot}min-1. The quantity of OH ion in HA ceramics sintered by SPS was decreased with increasing temperature of sintering. Transparent HA ceramics were prepared by SPS at 900 deg. C and 1000 deg. C. In analysis of the densification behavior during sintering of HA by SPS, dominant sintering mechanism was plastic flow of densification. Transparent ceramics should be the most suitable materials to investigate the interface between human cells and ceramics.

  3. DEVELOPING FIRST-PRINCIPLES REACTIVE FORCE FIELDS AND DENSIFICATION PROCESS FOR Y-DOPED BaZrO3 PROTON-CONDUCTING CERAMICS

    SciTech Connect

    Boris Merinov; Adri van Duin; Sossina Haile; William A. Goddard III

    2004-04-30

    During the third semi-annual period we have mostly finished a series of QM calculations on relevant metals (Pt, Zr, Y, Ba), metal alloys (Y/Zr), metal oxides (ZrO{sub 2}, Y{sub 2}O{sub 3}, BaO) and Y-doped BaZrO{sub 3}. Based on these data we started developing ReaxFF for further MD simulations of different physico-chemical processes in the electrolyte and at the electrode/electrolyte interface. To accelerate the densification process of BaZrO{sub 3} ceramics at lower temperature an initial screening of all transition elements in the series Sc to Zn has been carried out. It turned out that NiO, CuO and ZnO are the most effective additives for enhancing barium zirconate densification. Characterization (X-ray diffraction, scanning electron microscopy, and impedance spectroscopy) of Zn-, Cu- and Ni-modified BYZ has been performed. The temperature dependence of the bulk conductivity {sigma}{sub gi}, grain boundary conductivity {sigma}{sub gb}, and specific grain boundary conductivity {sigma}{sub sp.gb} were measured. The bulk conductivity of BYZ-Zn4 is slightly lower than that of unmodified BYZ.

  4. Influence of stress, temperature and crystal morphology on isothermal densification and specific surface area decrease of new snow

    NASA Astrophysics Data System (ADS)

    Schleef, S.; Löwe, H.; Schneebeli, M.

    2014-10-01

    Laboratory-based, experimental data for the microstructural evolution of new snow are scarce, though applications would benefit from a quantitative characterization of the main influences. To this end, we have analyzed the metamorphism and concurrent densification of new snow under isothermal conditions by means of X-ray microtomography and compiled a comprehensive data set of 45 time series. In contrast to previous measurements on isothermal metamorphism on time scales of weeks to months, we analyzed the initial 24-48 h of snow evolution at a high temporal resolution of 3 hours. The data set comprised natural and laboratory-grown snow, and experimental conditions included systematic variations of overburden stress, temperature and crystal habit to address the main influences on specific surface area (SSA) decrease rate and densification rate in a snowpack. For all conditions, we found a linear relation between density and SSA, indicating that metamorphism has an immediate influence for the densification of new snow. The slope of the linear relation, however, depends on the other parameters which were analyzed individually to derive a best-fit parameterization for the SSA decrease rate and densification rate. In the investigated parameter range, we found that the initial value of the SSA constituted the main morphological influence on the SSA decrease rate. In turn, the SSA decrease rate constituted the main influence on the densification rate.

  5. Initial stage densification during spark plasma sintering of Fe-based amorphous alloy powder: Analysis of viscous flow

    NASA Astrophysics Data System (ADS)

    Paul, Tanaji; Harimkar, Sandip P.

    2016-10-01

    Understanding the mechanism of densification of amorphous alloy powders is important for determining the parameters during sintering of these materials. In this paper, we report on the analysis of densification of Fe48Cr15Mo14Y2C15B6 amorphous alloy powder during spark plasma sintering. Sintering up to 1000 °C resulted in two clearly distinguishable stages of densification: stage I from 320 °C to 740 °C and stage II from 830 °C to 1000 °C. The maximum densification rate during stage I was attained at 585 °C up to which the sample remained fully amorphous. During the entire stage II, the sample was fully crystalline, and the maximum densification rate attained at 935 °C was much lower than that observed during stage I. Viscous flow during stage I was analyzed, yielding an estimate of the activation energy to be 94.0 ± 0.2 kJ mol-1 in the temperature range from 525 °C to 580 °C.

  6. Impact of densification on microstructure and transport properties of CaFe5O7

    NASA Astrophysics Data System (ADS)

    Delacotte, C.; Hébert, S.; Hardy, V.; Bréard, Y.; Maki, R.; Mori, T.; Pelloquin, D.

    2016-04-01

    Monophasic CaFe5O7 ceramic has been synthesized by solid state route. Its microstructural features have been studied by diffraction techniques and electron microscopy images before and after Spark Plasma Sintering (SPS) annealings. This work is completed by measurements of electrical and thermal properties. Especially, attention is focused around the structural and electronic transition at 360 K for which specific heat measurements have revealed a sharp peak. Densification by SPS techniques led to a significant improvement of electrical conductivity above 360 K.

  7. Multi-material laser densification (MMLD) of dental restorations: Process optimization and properties evaluation

    NASA Astrophysics Data System (ADS)

    Li, Xiaoxuan

    This Ph.D. thesis proposes to investigate the feasibility of laser-assisted dental restoration and to develop a fundamental understanding of the interaction between laser beam and dental materials. Traditional dental restorations are produced by the porcelain-fused-to-metal (PFM) process, in which a dental restoration is cast from a metallic alloy and then coated with dental porcelains by multiple furnace-firing processes. PFM method is labor-intensive and hence very expensive. In order to fabricate dental restoration units faster and more cost-effectively, the Solid Freeform Fabrication (SFF) technique has been employed in this study. In particular, a Multi-Material Laser Densification (MMLD) process has been investigated for its potential to fabricate artificial teeth automatically from 3-D computer dental tooth files. Based on the principle of SFF, the MMLD process utilizes a micro-extruder system to deliver commercial dental alloy and porcelain slurry in a computer-controlled pattern line by line and layer by layer. Instead of firing the artificial tooth/teeth in a furnace, the extruded dental materials are laser scanned to convert the loose powder to a fully dense body. Different laser densification parameters including the densification temperature, laser output power, laser beam size, line dimension, ratio of the beam size to line width, beam scanning rate, processing atmosphere and pressure, dental powder state (powder bed or slurry), powder particle size, etc. have been used to evaluate their effects on the microstructures and properties of the laser densified dental body, and hence to optimize MMLD conditions. Furthermore, laser-scanning induced phase transformations in dental porcelains have been studied because the transformations have great impact on coefficient of thermal expansion (CTE) of dental porcelains, which should match that of dental alloy substrate. Since a single dental material line delivered by the MMLD system functions as a "construction

  8. Large scale densification of a nuclear waste ceramic by hot isostatic pressing

    SciTech Connect

    Hoenig, C.L.; Larker, H.T.

    1983-12-01

    Experimental results show that loaded bellows steel canisters, evacuated and sealed, can be cold-isostatically pressed before HIP from an initial density of 26 to 46% theoretical. Calcined powders are hygroscopic and may require degassing at 600 degrees C under vaccum, and residual gas, unless removed, is an impediment to HIP densification. Results also show that degassed synroc D powder in 50 kg quantities can be HIP densified to greater than 97% theoretical density at 1100 degrees C, 150 MPa, for 5h in a bellows canister without radial buckling. The authors believe that on the basis of this preliminary study, full-scale nuclear waste monoliths can be produced by HIP.

  9. Effect of Densification on the Density of Vibrational States of Glasses

    SciTech Connect

    Monaco, A.; Chumakov, A. I.; Monaco, G.; Crichton, W. A.; Rueffer, R.; Meyer, A.; Comez, L.; Fioretto, D.; Korecki, J.

    2006-09-29

    We studied the effect of densification on the vibrational dynamics of a Na{sub 2}FeSi{sub 3}O{sub 8} glass. The density of vibrational states (DOS) has been measured using nuclear inelastic scattering. The corresponding changes in the microscopic, intermediate-range, and macroscopic properties have also been investigated. The results reveal that, in the absence of local structure transformations, the Debye level and the glass-specific excess of vibrational states above it have the same dependence on density, and the evolution of the DOS is fully described by the transformation of the elastic medium.

  10. Femtosecond laser-induced stress-free ultra-densification inside porous glass

    NASA Astrophysics Data System (ADS)

    Veiko, Vadim P.; Kudryashov, Sergey I.; Sergeev, Maksim M.; Zakoldaev, Roman A.; Danilov, Pavel A.; Ionin, Andrey A.; Antropova, Tatiana V.; Anfimova, Irina N.

    2016-05-01

    Unusually high densification  ⩽26% was obtained without lateral residual stresses within the laser beam waist inside porous glass during its multi-shot femtosecond laser irradiation, which may induce in the glass the related high refractive index change ~0.1. Corresponding laser irradiation regimes, resulting in such ultra-densification, decompaction and voids inside the glass, were revealed as a function of laser pulse energy and scanning rate, and were discussed in terms of thermal and hydrodynamic processes in the silica network.

  11. THE EFFECT OF TEMPERATURE AND UNIAXIAL PRESSURE ON THE DENSIFICATION BEHAVIOR OF SILICA AEROGEL GRANULES

    SciTech Connect

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

    2012-10-01

    Materials are being developed in U.S. for the removal and immobilization of iodine from gaseous products of nuclear fuel reprocessing in support of the Fuel Cycle Technology Separations and Waste Forms Campaign. The silver-functionalized silica aerogel proved to be an excellent candidate for this treatment because of its high selectivity and sorption capacity for radioiodine and its possible conversion to a durable silica-based waste form. The present study investigated with nitrogen sorption and helium pycnometry the effect of pressureless isothermal sintering at temperatures of 900-1400°C for 2.5-90 min or isothermal hot-pressing at 1200°C for 2.5 min on densification of raw and silver-functionalized silica aerogel granules. Rapid sintering was observed at 1050 and 1200°C. Only 15 min of pressureless sintering at 1200°C resulted in almost complete densification. The macropores disappeared, surface area decreased from 1114 m2/g to 25 m2/g, pore volume from 7.41 cm3/g to 0.09 cm3/g, and adsorption pore size from 18.7 to 7 nm. The skeletal density of sintered granules was similar to the bulk density of amorphous silica (2.2 g/cm3). The hot-pressing accelerated the sintering process, decreasing significantly the pore size and volume.

  12. Densification route and mechanical properties of Si3N4-bioglass biocomposites.

    PubMed

    Amaral, M; Lopes, M A; Silva, R F; Santos, J D

    2002-02-01

    The processing route and the final microstructural and mechanical characteristics of a novel biomaterial composite are described. This new material is composed of 70 wt% Si3N4 ceramic phase and 30 wt% bioglass, the later performing as a liquid sintering aid system and simultaneously providing bioactivity characteristics to the composite. The conditions for fabrication of an almost fully dense material (approximately 98% of relative density) were pursued. Optimised parameters were 1350 degrees C-40 min-30 MPa by hot-pressing technique. The very fast densification rate of the process avoided the crystallisation of the bioglass intergranular phase and therefore its intrinsic properties were maintained. Also, the large amount of glassy phase assured the densification by liquid phase assisted grain rearrangement without Si3N4 phase transformation. The final mechanical properties of the Si3N4 bioglass were as follows: fracture toughness, K(IC) = 4.4 MPa m(1/2); Vickers hardness, Hv = 10.3 GPa; Young's modulus, E = 197 GPa; bending strength, sigma(g) = 383 MPa; Weibull modulus, m = 8.3. These values provide an attractive set of properties among other bioactive materials, namely by upgrading the main drawback of bioceramcs and bioglasses for high-load medical applications, which is the lack of satisfactory fracture toughness.

  13. GNSS-based densification of the ITRF velocity field through a collaborative approach

    NASA Astrophysics Data System (ADS)

    Legrand, Juliette; Bruyninx, Carine; Craymer, Michael; Dawson, John; Griffiths, Jake; Kenyeres, Ambrus; Rebischung, Paul; Sánchez, Laura; Santamaría-Gómez, Alvaro; Saria, Elifuraha; Altamimi, Zuheir

    2015-04-01

    The objective of the IAG Working Group "Integration of Dense Velocity Fields in the ITRF" is to provide a GNSS-based dense, unified and reliable velocity field globally referenced in the ITRF (International Terrestrial Reference Frame) and useful for geodynamical and geophysical interpretations. The WG is embedded in IAG Sub-Commission 1.3 "Regional Reference Frames" where it coexists with the Regional Reference Frame Sub-Commissions AFREF (Africa), APREF (Asia & Pacific), EUREF (Europe), NAREF (North America), SCAR (Antarctica), SIRGAS (Latin America & Caribbean). These IAG Regional Reference Frame sub-commissions are responsible for providing GNSS-based densified weekly solutions for their region. To obtain such a densified velocity field, the WG combined the individual weekly solutions from 7 individual contributors (AFREF, APREF, EUREF, NAREF (NGS, GSB), SIRGAS, IGS) and then stacked these weekly combined solutions in order to derive a ITRF2008 densification as well as the associated residual position time series for more than 2800 sites. Here we present the latest densification results.

  14. Simulation of the densification of real open-celled foam microstructures

    NASA Astrophysics Data System (ADS)

    Brydon, A. D.; Bardenhagen, S. G.; Miller, E. A.; Seidler, G. T.

    2005-12-01

    Ubiquitous in nature and finding applications in engineering systems, cellular solids are an increasingly important class of materials. Foams are an important subclass of cellular solids with applications as packing materials and energy absorbers due to their unique properties. A better understanding of foam mechanical properties and their dependence on microstructural details would facilitate manufacture of tailored materials and development of constitutive models for their bulk response. Numerical simulation of these materials, while offering great promise toward furthering understanding, has also served to convincingly demonstrate the inherent complexity and associated modeling challenges. The large range of deformations which foams are subjected to in routine engineering applications is a fundamental source of complication in modeling the details of foam deformation on the scale of foam struts. It requires accurate handling of large material deformations and complex contact mechanics, both well established numerical challenges. A further complication is the replication of complex foam microstructure geometry in numerical simulations. Here various advantages of certain particle methods, in particular their compatibility with the determination of three-dimensional geometry via X-ray microtomography, are exploited to simulate the compression of "real" foam microstructures into densification. With attention paid to representative volume element size, predictions are made regarding bulk response, dynamic effects, and deformed microstructural character, for real polymeric, open-cell foams. These predictions include a negative Poisson's ratio in the stress plateau, and increased difficulty in removing residual porosity during densification.

  15. Densification of silica glass induced by 0.8 and 1.5 {mu}m intense femtosecond laser pulses

    SciTech Connect

    Saliminia, A.; Nguyen, N.T.; Chin, S.L.; Vallee, R.

    2006-05-01

    We investigate the physical mechanisms responsible for waveguide formation in silica glass induced by 1 kHz intense femtosecond laser pulses from a Ti-sapphire laser at 0.8 {mu}m as well as from a femtosecond optical parametric amplifier at 1.5 {mu}m. It is demonstrated that the densification taking place at the irradiated region is the principal cause for refractive index change in the waveguides written with both 0.8 and 1.5 {mu}m pulses. The birefringence induced by the stress arising from such densification and its behavior against thermal annealing are also studied.

  16. Fabrication and characterization of Si3N4 ceramics without additives by high pressure hot pressing

    NASA Technical Reports Server (NTRS)

    Shimada, M.; Tanaka, A.; Yamada, T.; Koizumi, M.

    1984-01-01

    High pressure hot-pressing of Si3N4 without additives was performed using various kinds of Si3N4 powder as starting materials, and the relation between densification and alpha-beta phase transformation was studied. The temperature dependences of Vickers microhardness and fracture toughness were also examined. Densification of Si3N4 was divided into three stages, and it was found that densification and phase transformation of Si3N4 under pressure were closely associated. The results of the temperature dependence of Vickers microhardness indicated that the high-temperature hardness was strongly influenced not only by the density and microstructure of sintered body but also by the purity of starting powder. The fracture toughness values of Si3N4 bodies without additives were 3.29-4.39 MN/m to the 3/2 power and independent of temperature up to 1400 C.

  17. Influence of stress, temperature and crystal habit on isothermal densification and specific surface area decrease of new snow

    NASA Astrophysics Data System (ADS)

    Schleef, S.; Löwe, H.; Schneebeli, M.

    2014-03-01

    Laboratory-based, experimental data for the microstructural evolution of new snow is scarce, though applications would benefit from a quantitative characterization of the main mechanism underlying the initial microstructural changes. To this end we have analyzed the metamorphism and concurrent densification of new snow under isothermal conditions by means of X-ray microtomography and compiled a comprehensive data set of 45 time series covering the practically relevant short time behavior within the first 24-48 h in high temporal resolution. The data set comprises natural and laboratory grown snow and experimental conditions include systematic variations of overburden stress, temperature and crystal habit to address the main influences on specific surface area (SSA) decrease rate and densification rate in a natural snowpack. For all conditions we find a linear increase of the density with the SSA, indicating that metamorphism has a key influence for the densification of new snow. Corroborated by the analysis of the individual influences of external conditions we derive a best-fit parametrization for the SSA decrease rate and the densification rate as required for applications.

  18. Effect of sintering temperature on densification and mechanical properties of pressureless sintered CNT-alumina nanocomposites

    NASA Astrophysics Data System (ADS)

    Bakhsh, N.; Khalid, F. A.; Hakeem, Abbas S.

    2014-06-01

    Carbon nanotubes (CNTs) exhibit excellent mechanical, electrical and thermal properties thus have been considered for applications in the production of nanocomposite materials. This work presents results of sintered CNTs-reinforced alumina nanocomposites that can be used for many structural and engineering applications. Gas purging sonication (GPS) was used to achieve homogeneous dispersion of CNTs in alumina powder. Nanocomposites were synthesized by conventional pressureless sintering technique using varying amounts of CNTs in alumina matrix. Densification, hardness and fracture toughness of the resulted nanocomposites were examined. It is found that considerable improvement in fracture toughness at 1 wt% CNT-alumina nanocomposite has occurred. Role of CNTs in improving the fracture toughness of nanocomposites is explained which is attributed to well known bridging and pullout mechanism of CNTs in the matrix.

  19. Pupil densification of obstructed monolithic apertures for high-contrast coronagraphy

    NASA Astrophysics Data System (ADS)

    Aime, C.; Soummer, R.; Gori, P. M.

    We give in this short communication the principle of the densification of a large classical on-axis aperture, with aperture central obscuration and spider arms into a full circular unobstructed aperture, for application to high-contrast coronagraphy. An example is shown using a VLT like aperture. In space, such a technique would allow to produce a perfect null of the star image using coronagraphic techniques such as the 4QC or the PKC, at the expense of a small reduction of the transmitted light. The drawback of the technique is that a surprisingly very small ZOF is obtained, if the telescope full resolution is considered. However, if a loss of resolution of a factor 2 is accepted, then the system might behave as a perfect imaging system. The technique is found useless for ground based observations with the Strehl ratios reached at the present time.

  20. Densification effects of the carbon nanotube pillar array on field-emission properties

    NASA Astrophysics Data System (ADS)

    Wang, Kuang-Yu; Chou, Chia-Hsin; Liao, Chan-Yu; Li, Yu-Ren; Cheng, Huang-Chung

    2016-06-01

    In this study, a simple densification method for carbon nanotube (CNT) pillars is proposed to achieve high-performance field emission characteristics and stable emission. Through capillary force during solution evaporation, the CNT density in each pillar can be increased by about six times without causing damage to the crystallinity of CNTs. The densified CNT pillars exhibit lower series resistance, sharper pillars, better contacts, higher thermal conductivity, and better mechanical stiffness than as-grown ones. Therefore, the threshold field of the field emitter with such CNT pillars of 50 µm height can be reduced to 1.98 V/µm, as compared with 2.2 V/µm for the undensified ones. Moreover, the fluctuation of field-emission current decreases from 15.5 to 9.4% after the stress tests at a field of 2 V/µm for 1800 s. These findings imply that the densified CNT pillars are promising for the field-emission applications.

  1. Regional Densification of the ITRF through the Integration of National Active GNSS Network Products

    NASA Astrophysics Data System (ADS)

    Kenyeres, Ambrus; Horvath, Tivadar; Stangl, Gunter; Garayt, Bruno; Hansen, Dionne; Valdes, Marcellino; Caporali, Alessandro; Figurski, Mariusz; Georgiev, Ivan; Droscak, Branislav; Franke, Peter; Jumare, Izolde; Nagl, Jaroslav; Pihlak, Priit; Huisman, Lennard

    2015-04-01

    The actual realization of the ITRS represents the most precise station positions and velocities at selected set of sites. The scientific and practical applications may require the access to the global 3D reference frame in a dense network without loss of consistency and reliability. Relying on the long term homogeneously analyzed data the dense national permanent GNSS networks shall be the ideal tool for such reference frame densification. In the frame of the ongoing EPN densification the national active networks are integrated and a homogeneous, dense position and velocity product is being derived based on the actual ITRS realization and using the EPN as backbone infrastructure. In order to minimize inconsistencies (e.g. site naming, discontinuities, constraint handling) the only way to get a uniform, homogeneous cumulative solution from national to global scales is the integration done relying on the weekly SINEX product level. The integration is being performed using the CATREF software (Altamimi et al, IGN) and based on the Minimum Constraint approach. The derived position and velocity product will be an essential material for various geokinematic studies (PGR, intraplate and plate boundary zone investigations), and also for the better definition and realization of ETRS89. This work is very well inline with the goals of relevant European initiatives in the frame of EPOS, EUREF (WG on Deformation Models), CEGRN, EUPOS, IAG (WG on Unified Dense Velocity Fields). The work is well in progress, up to 15 years of weekly SINEX files are already available and analyzed from 17 countries, and considering the countries in negotiation phase the full continental coverage will be reached within few years. The actual database contains more close to 3000 sites. In this presentation a status report is shown and the first version of the position/velocity product with related interpretation options are introduced as well.

  2. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    NASA Astrophysics Data System (ADS)

    Ge, Lin; Li, Jiang; Qu, Haiyun; Wang, Juntao; Liu, Jiao; Dai, Jiawei; Zhou, Zhiwei; Liu, Binglong; Kou, Huamin; Shi, Yun; Wang, Zheng; Pan, Yubai; Gao, Qingsong; Guo, Jingkun

    2016-10-01

    The sintering behavior and doping concentration profile of the planar waveguide YAG/Nd:YAG/YAG ceramics by the tape casting and solid-state reaction method were investigated on the basis of densification trajectory, microstructure evolution, and Nd3+ ions diffusion. The porosity of the green body by tape casting and cold isostatic pressing is about 38.6%. And the green bodies were consolidated from 1100 °C to 1800 °C for 0.5-20 h to study the densification and the doping diffusion behaviors. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. With the increase of temperature, two sintering stages occur, corresponding to remarkable densification and significant grain growth, respectively. The mechanism controlling densification at 1550 °C is grain boundary diffusion. The diffusion of Nd3+ ions is more sensitive to temperature than the sintering time, and the minimum temperature required for the obvious diffusion of Nd3+ ions is higher than 1700 °C. Finally, planar waveguide YAG/1.5 at.%Nd:YAG/YAG transparent ceramics with in-line transmittance of 84.8% at 1064 nm were obtained by vacuum-sintering at 1780 °C for 30 h. The fluorescence lifetime of 4F3/2 state of Nd3+ in the specimen is about 259 μs. The prepared ceramic waveguide was tested in a laser amplifier and the laser pulse was amplificated from 87 mJ to 238 mJ, with the pump energy of 680 mJ.

  3. Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

    PubMed Central

    Copic, Davor; Park, Sei Jin; Tawfick, Sameh; De Volder, Michael; Hart, A. John

    2012-01-01

    The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT

  4. Mathematical Model and Experimental Results for Cryogenic Densification and Sub-Cooling Using a Submerged Cooling Source

    NASA Technical Reports Server (NTRS)

    Partridge, J. K.; Notardonato, W. U.; Johnson, W. L.; Tuttle, J. W.

    2011-01-01

    Among the many factors that determine overall rocket performance, propellant density is important because it affects the size of the rocket. Thus, in order to decrease the size of a rocket, it may be desirable to increase the density of propellants. This study analyzes the concept of increasing the propellant density by employing a cooling source submerged in the liquid propellant. A simple, mathematical model was developed to predict the rate of densification and the propellant temperature profile. The mathematical model is generic and applicable to multiple propellants. The densification rate was determined experimentally by submerging a cooling source in liquid oxygen at constant, positive pressure, and measuring the time rate of change in temperature with respect to vertical position. The results from the mathematical model provided a reasonable fit when compared to experimental results.

  5. Densification and residual stress induced by CO2 laser-based mitigation of SiO2 surfaces

    SciTech Connect

    Feit, M D; Matthews, M J; Soules, T F; Stolken, J S

    2010-10-21

    Knowing the ultimate surface morphology resulting from CO{sub 2} laser mitigation of induced laser damage is important both for determining adequate treatment protocols, and for preventing deleterious intensification upon subsequent illumination of downstream optics. Physical effects such as evaporation, viscous flow and densification can strongly affect the final morphology of the treated site. Evaporation is a strong function of temperature and will play a leading role in determining pit shapes when the evaporation rate is large, both because of material loss and redeposition. Viscous motion of the hot molten material during heating and cooling can redistribute material due to surface tension gradients (Marangoni effect) and vapor recoil pressure effects. Less well known, perhaps, is that silica can densify as a result of structural relaxation, to a degree depending on the local thermal history. The specific volume shrinkage due to structural relaxation can be mistaken for material loss due to evaporation. Unlike evaporation, however, local density change can be reversed by post annealing. All of these effects must be taken into account to adequately describe the final morphology and optical properties of single and multiple-pass mitigation protocols. We have investigated, experimentally and theoretically, the significance of such densification on residual stress and under what circumstances it can compete with evaporation in determining the ultimate post treatment surface shape. In general, understanding final surface configurations requires taking all these factors including local structural relaxation densification, and therefore the thermal history, into account. We find that surface depressions due to densification can dominate surface morphology in the non-evaporative regime when peak temperatures are below 2100K.

  6. Laser induced densification of cerium gadolinium oxide: Application to single-chamber solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Mariño, Mariana; Rieu, Mathilde; Viricelle, Jean-Paul; Garrelie, Florence

    2016-06-01

    In single-chamber solid oxide fuel cells (SC-SOFC), anode and cathode are placed in a gas chamber where they are exposed to a fuel/air mixture. Similarly to conventional dual-chamber SOFC, the anode and the cathode are separated by an electrolyte. However, as in the SC-SOFC configuration the electrolyte does not play tightness role between compartments, this one can be a porous layer. Nevertheless, it is necessary to have a diffusion barrier to prevent the transportation of hydrogen produced locally at the anode to the cathode that reduces fuel cell performances. This study aims to obtain directly a diffusion barrier through the surface densification of the electrolyte Ce0.9Gd0.1O1.95 (CGO) by a laser treatment. KrF excimer laser and Yb fiber laser irradiations were used at different fluences and number of pulses to modify the density of the electrolyte coating. Microstructural characterizations confirmed the modifications on the surface of the electrolyte for appropriate experimental conditions showing either grain growth or densified but cracked surfaces. Gas permeation and electrical conductivities of the modified electrolyte were evaluated. Finally SC-SOFC performances were improved for the cells presenting grain growth at the electrolyte surface.

  7. Enhanced densification, strength and molecular mechanisms in shock compressed porous silicon

    NASA Astrophysics Data System (ADS)

    Lane, J. Matthew D.; Vogler, Tracy J.

    2015-06-01

    In most porous materials, void collapse during shock compression couples mechanical energy to thermal energy. Increased temperature drives up pressures and lowers densities in the final Hugoniot states as compared to full-density samples. Some materials, however, exhibit an anomalous enhanced densification in their Hugoniot states when porosity is introduced. We have recently shown that silicon is such a material, and demonstrated a molecular mechanism for the effect using molecular simulation. We will review results from large-scale non-equilibrium molecular dynamics (NEMD) and Hugoniotstat simulations of shock compressed porous silicon, highlighting the mechanism by which porosity produces local shear which nucleate partial phase transition and localized melting at shock pressures below typical thresholds in these materials. Further, we will characterize the stress states and strength of the material as a function of porosity from 5 to 50 percent and with various porosity microstructures. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  8. Effect of relative humidity during tabletting on matrix formation of hydrocolloids: densification behavior of cellulose ethers.

    PubMed

    Picker, K M; Mielck, J B

    1998-02-01

    The aim of this research was to investigate the elastic-plastic deformation behavior of the cellulose ethers hydroxypropylmethylcellulose (HPMC), hydroxyethylmethylcellulose (HEMC), and sodium carboxymethylcellulose (NaCMC) at relative humidities (RH) of 38, 57, and 75% and assess how the release of drugs embedded in such matrices is affected by the inner structure of the tablets formed during tabletting. Sorption and desorption isotherms and glass transition temperature were determined between 32 and 75% RH. The materials were equilibrated at 38, 57, and 75% RH and tabletted to a range of graded maximum relative densities. Pressure-time and displacement-time curves were analyzed by use of the Heckel function and a modified Weibull function (pressure-time only). After equilibration at the different RHs, all materials were in the glassy state. The respective degrees of polymerization had negligible effect on the absolute content of water, the sorption isotherms, and finally the densification behavior. At 38% RH, NaCMC contains the same amount of water as HPMC and HEMC, but deforms less plastically than the latter. This is attributed to tight binding of the water of hydration in the former. With increasing RH, NaCMC becomes only a little more plastic than both HPMC and HEMC, although it contains more than twice the amount of water. The binding strength of water and its molecular mobility, not the amount, seems to determine the readiness for volume reduction under load.

  9. Crystallization kinetics and densification of YAG nanoparticles from various chelating agents

    SciTech Connect

    Hou, J.G.; Kumar, R.V.; Qu, Y.F.; Krsmanovic, Dalibor

    2009-08-05

    Yttrium aluminium garnet (YAG, Y{sub 3}Al{sub 5}O{sub 12}) nanoparticles were prepared using sonochemical sol-gel method with three different chelating agents and the effect of crystallization kinetics was investigated with differential scanning calorimetry-thermogravimetry (DSC-TG). The activation energy values of crystallization for the as-synthesized YAG nanoparticles using citric acid (CA), glycine (G) or a mixture of citric acid-glycine (CA-G), as chelating agents were found to be 160.5, 142.2 and 140.4 kJ mol{sup -1} and the corresponding Avarami constants were 2.2, 2.1 and 1.9, respectively. Samples produced with the mixed chelating agent under sonification, could be crystallized to single phase YAG nanoparticles (10-65 nm) after annealing at 1100 deg. C. Pellets made from the annealed YAG particles could be sintered to a relative density greater than 99% at 1500 deg. C with a grain size of 4.5 {mu}m, made up of secondary particles formed from primary nano-crystals within the grains. Grain size and relative density increased with different chelating agents from CA to G and CA-G in the increasing order when YAG samples were sintered. Grain growth and densification occurred at a relatively low temperature of 1500 deg. C as compared to over 1800 deg. C in solid-state reactions.

  10. Improved progressive TIN densification filtering algorithm for airborne LiDAR data in forested areas

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoqian; Guo, Qinghua; Su, Yanjun; Xue, Baolin

    2016-07-01

    Filtering of light detection and ranging (LiDAR) data into the ground and non-ground points is a fundamental step in processing raw airborne LiDAR data. This paper proposes an improved progressive triangulated irregular network (TIN) densification (IPTD) filtering algorithm that can cope with a variety of forested landscapes, particularly both topographically and environmentally complex regions. The IPTD filtering algorithm consists of three steps: (1) acquiring potential ground seed points using the morphological method; (2) obtaining accurate ground seed points; and (3) building a TIN-based model and iteratively densifying TIN. The IPTD filtering algorithm was tested in 15 forested sites with various terrains (i.e., elevation and slope) and vegetation conditions (i.e., canopy cover and tree height), and was compared with seven other commonly used filtering algorithms (including morphology-based, slope-based, and interpolation-based filtering algorithms). Results show that the IPTD achieves the highest filtering accuracy for nine of the 15 sites. In general, it outperforms the other filtering algorithms, yielding the lowest average total error of 3.15% and the highest average kappa coefficient of 89.53%.

  11. Frost Growth and Densification on a Flat Surface in Laminar Flow with Variable Humidity

    NASA Technical Reports Server (NTRS)

    Kandula, M.

    2012-01-01

    Experiments are performed concerning frost growth and densification in laminar flow over a flat surface under conditions of constant and variable humidity. The flat plate test specimen is made of aluminum-6031, and has dimensions of 0.3 mx0.3 mx6.35 mm. Results for the first variable humidity case are obtained for a plate temperature of 255.4 K, air velocity of 1.77 m/s, air temperature of 295.1 K, and a relative humidity continuously ranging from 81 to 54%. The second variable humidity test case corresponds to plate temperature of 255.4 K, air velocity of 2.44 m/s, air temperature of 291.8 K, and a relative humidity ranging from 66 to 59%. Results for the constant humidity case are obtained for a plate temperature of 263.7 K, air velocity of 1.7 m/s, air temperature of 295 K, and a relative humidity of 71.6 %. Comparisons of the data with the author's frost model extended to accommodate variable humidity suggest satisfactory agreement between the theory and the data for both constant and variable humidity.

  12. Locally enhanced dissolution rate as a probe for nanocontact-induced densification in oxide glasses.

    PubMed

    Niu, Yi-Fan; Han, Kun; Guin, Jean-Pierre

    2012-07-24

    Atomic force microscopy (AFM) was used to characterize the surface damage (nanoindentations) effect on the chemical durability of glass surfaces (silica and soda-lime silicate glasses, WG). In basic solutions, an enhanced dissolution rate is reported and quantified at indentation sites (+10.5 nm/h and +52 nm/h for silica and WG, respectively) whereas none was observed once the indented surfaces were thermally annealed at 0.9 × T(g) for 2 h, a thermal treatment known for curing high pressure-induced permanent densification in oxides glasses. A direct link between high pressure-induced structural modifications encountered during nanoindentation and the measured dissolution rates is established. It is shown that this property conjointly used with the high resolution of the atomic force microscope may be used for probing, at the nanometer scale, the size and the nature of the structurally modified area underneath residual nanoindentation impressions. As an example, for 10 mN Vickers nanoindentations on WG, the zone affected by the permanently and structurally modified zone under the residual impression is found to be equal to (741 ± 30) nm with a transition zone thickness from the fully densified material to the elastically deformed one ranging between 115 and 165 nm.

  13. Numerical investigation of FAST powder consolidation of Al2O3 and additive free β-SiC

    NASA Astrophysics Data System (ADS)

    Allen, J. B.; Cornwell, C. F.; Carlson, T.; Marsh, C. P.

    2015-02-01

    In this work we examine ceramic synthesis through powder consolidation and the field assisted sintering technique. In particular, we investigate the sintering of Al2O3 and additive free β -SiC from both an experimental and numerical perspective. For the numerical model, the continuum theory of sintering model is employed, and the densification mechanisms corresponding to power law creep and grain boundary diffusion are considered. Experiments are used for comparison and validation purposes. The results indicate that in general, the densification kinetics simulated by the numerical model compare favorably with the experimental results. Parametric studies involving initial grain size, heating rate, and applied stress are also examined using the numerical model, and confirm many of the expected results from previous research, including increased densification due to higher heating rates, smaller grain sizes, and increased applied loading conditions.

  14. The Effect of High-Pressure Devitrification and Densification on Ballistic-Penetration Resistance of Fused Silica

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; Avuthu, V.; Snipes, J. S.; Ramaswami, S.; Galgalikar, R.

    2015-12-01

    Recent experimental and molecular-level computational analyses have indicated that fused silica, when subjected to pressures of several tens of GPa, can experience irreversible devitrification and densification. Such changes in the fused-silica molecular-level structure are associated with absorption and/or dissipation of the strain energy acquired by fused silica during high-pressure compression. This finding may have important practical consequences in applications for fused silica such as windshields and windows of military vehicles, portholes in ships, ground vehicles, spacecraft, etc. In the present work, our prior molecular-level computational results pertaining to the response of fused silica to high pressures (and shear stresses) are used to enrich a continuum-type constitutive model (that is, the so-called Johnson-Holmquist-2, JH2, model) for this material. Since the aforementioned devitrification and permanent densification processes modify the response of fused silica to the pressure as well as to the deviatoric part of the stress, changes had to be made in both the JH2 equation of state and the strength model. To assess the potential improvements in respect to the ballistic-penetration resistance of this material brought about by the fused-silica devitrification and permanent densification processes, a series of transient non-linear dynamics finite-element analyses of the transverse impact of a fused-silica test plate with a solid right-circular cylindrical steel projectile were conducted. The results obtained revealed that, provided the projectile incident velocity and, hence, the attendant pressure, is sufficiently high, fused silica can undergo impact-induced devitrification, which improves its ballistic-penetration resistance.

  15. Remote sensing of impervious surface growth: A framework for quantifying urban expansion and re-densification mechanisms

    NASA Astrophysics Data System (ADS)

    Shahtahmassebi, Amir Reza; Song, Jie; Zheng, Qing; Blackburn, George Alan; Wang, Ke; Huang, Ling Yan; Pan, Yi; Moore, Nathan; Shahtahmassebi, Golnaz; Sadrabadi Haghighi, Reza; Deng, Jing Song

    2016-04-01

    A substantial body of literature has accumulated on the topic of using remotely sensed data to map impervious surfaces which are widely recognized as an important indicator of urbanization. However, the remote sensing of impervious surface growth has not been successfully addressed. This study proposes a new framework for deriving and summarizing urban expansion and re-densification using time series of impervious surface fractions (ISFs) derived from remotely sensed imagery. This approach integrates multiple endmember spectral mixture analysis (MESMA), analysis of regression residuals, spatial statistics (Getis_Ord) and urban growth theories; hence, the framework is abbreviated as MRGU. The performance of MRGU was compared with commonly used change detection techniques in order to evaluate the effectiveness of the approach. The results suggested that the ISF regression residuals were optimal for detecting impervious surface changes while Getis_Ord was effective for mapping hotspot regions in the regression residuals image. Moreover, the MRGU outputs agreed with the mechanisms proposed in several existing urban growth theories, but importantly the outputs enable the refinement of such models by explicitly accounting for the spatial distribution of both expansion and re-densification mechanisms. Based on Landsat data, the MRGU is somewhat restricted in its ability to measure re-densification in the urban core but this may be improved through the use of higher spatial resolution satellite imagery. The paper ends with an assessment of the present gaps in remote sensing of impervious surface growth and suggests some solutions. The application of impervious surface fractions in urban change detection is a stimulating new research idea which is driving future research with new models and algorithms.

  16. Effect of Heating Rate on Densification and Grain Growth During Spark Plasma Sintering of 93W-5.6Ni-1.4Fe Heavy Alloys

    NASA Astrophysics Data System (ADS)

    Hu, Ke; Li, Xiaoqiang; Qu, Shengguan; Li, Yuanyuan

    2013-09-01

    Blended 93W-5.6Ni-1.4Fe powders were sintered via the spark plasma sintering (SPS) technique using heating rates from 10 K min-1 to 380 K min-1 (10 °C min-1 to 380 °C min-1). The kinetics of densification and grain growth were analyzed to identify heating rate effects during the SPS of 93W-5.6Ni-1.4Fe powders. The activation energies for densification were calculated and compared with the experimental values for diffusion and other mass transport phenomena. The results show that for the slowly heated specimens [heating rate <100 K min-1 (100 °C min-1)], densification occurs mainly through dissolution-precipitation of W through the matrix phase and W grain boundary diffusion. The concurrent grain growth is dominated by surface diffusion at a low sintering temperature and by solution-reprecipitation and Ni-enhanced W grain boundary diffusion at a higher temperature. For the specimens sintered with heating rates higher than 100 K min-1 (100 °C min-1), the apparent activation energy value for the mechanism controlling densification is a strong function of the relative density, and fast densification controlled by multiple diffusion mechanisms and intensive viscous flow dominates over the grain growth. High SPS heating rate is favorable to obtain high density and fine-grained tungsten heavy alloys.

  17. Effects of Crustal Densification in Warm Slabs on In-slab Earthquakes and Episodic Tremors and Slips

    NASA Astrophysics Data System (ADS)

    Wang, K.

    2003-12-01

    During subduction, dehydration may facilitate earthquake rupture in both the slab crust and slab mantle. The up to 15% rock densification that accompanies the metabasalt-eclogite transformation is expected to have several mechanical consequences. In warm slabs such as Cascadia and Nankai, this transformation and mantle serpentine breakdown begin at rather shallow depths (30 - 50 km). The pervasively hydrated upper crust transforms to eclogite under equilibrium conditions, but the transformation of the anhydrous parts of the lower crust is kinetically delayed to greater depths. Therefore, densification begins in a thin layer along the top of the slab. Volume reduction gives rise to an equivalent stretching force in the thin layer in all slab-parallel directions, activating existing faults and developing new fractures. Analogous to a weak layer sandwiched between, and bonded to, two strong layers under stretching, fracture spacing in the weak layer scales with the layer thickness. The theory predicts that the densified thin layer must be ~{!0~}shattered~{!1~}. The shattered upper crust may have numerous small earthquakes but does not favor large ruptures. In contrast, the much more uniform lower crust and mantle can host larger ruptures, although seismic ruptures occur only in the limited hydrated parts. This explains the observation that relatively few earthquakes deeper inside the slab tend to have larger magnitudes than those just below the slab surface. For example, three recent damaging events (1999 Oaxaca, Mexico; 2001 Geiyo, Nankai; 2001 Nisqually, Cascadia) in warm slabs all occurred in the lower crust or mantle. The densification is generally a steady state process: An increasingly thinner slab moves into an increasingly thinner subduction "slot" continuously, with the downdip width of transition from normal to thinned crust scaling linearly with the subduction rate. However, at the fracture scale, the process is highly nonlinear, and there must be small

  18. Finite element modeling of dental restoration through multi-material laser densification

    NASA Astrophysics Data System (ADS)

    Dai, Kun

    To provide guidance for intelligent selection of various parameters in the Multi-Material Laser Densification (MMLD) process for dental restorations, finite element modeling (FEM) has been carried out to investigate the MMLD process. These modeling investigations include the thermal analysis of the nominal surface temperature that should be adopted during experiments in order to achieve the desired microstructure; the effects of the volume shrinkage due to transformation from a powder compact to dense liquid on the temperature distribution and the size of the transformation zone; the evolution of transient temperature, transient stresses, residual stresses and distortions; and the effects of laser processing conditions, such as fabrication sequences, laser scanning patterns, component sizes, preheating temperatures, laser scanning rates, initial porosities, and thicknesses of each powder layer, on the final quality of the component fabricated via the MMLD process. The simulation results are compared with the experiments. It is found that the predicted temperature distribution matches the experiments very well. The nominal surface temperature applied on the dental porcelain body should be below 1273 K to prevent the forming of the un-desired microstructure (i.e., a leucite-free glassy phase). The simplified models that do not include the volume shrinkage effect provide good estimations of the temperature field and the size of the laser-densified body, although the shape of the laser-densified body predicted is different from that obtained in the experiment. It is also fount that warping and residual thermal stresses of the laser-densified component are more sensitive to the chamber preheating temperature and the thickness of each powder layer than to the laser scanning rate and the initial porosity of the powder layer. The major mechanism responsible for these phenomena is identified to be related to the change of the temperature gradient induced by these laser

  19. Sub-micron fracture mechanism in silica-based glass activated by permanent densification from high-strain loading

    DOE PAGESBeta

    Wereszczak, Andrew A.; Waters, Shirley B.; Parten, Randy J.; Pye, L. David

    2016-04-26

    Several silica-based glasses were fractured at high strain energy via drop-weight testing on small specimens. A cylindrical specimen geometry was chosen to promote initially simple, axisymmetric, and uniform compressive loading. The imposed uniaxial compressive strain at impact was sufficiently high to qualitatively cause permanent densification. Produced fragments were collected for postmortem and a fraction of them, for all the silica-based glasses, consistently had distinct sub-micron-sized fractures (~ 300–1000 nm), designated here as “microkernels”, on their surfaces. They would most often appear as a sub-micron pore on the fragment - apparently if the microkernel had popped out as a consequence ofmore » the local crack plane running through it, tensile-strain release, and the associated formation of the fragment it was on. No fractographic evidence was found to show the microkernels were associated with local failure initiation. However, their positioning and habit sometimes suggested they were associated with localized crack branching and that they could have influenced secondary fracturing that occurred during overall crushing and comminution and associated fragment size and shape creation. Furthermore, the size range of these microkernels is much too small to affect structural flexure strength of these glasses for most applications but are of a size and concentration that may affect their ballistic, shock, crush, and comminution responses when permanent densification is concomitantly occurring.« less

  20. Effect of heating rate on the densification of NdFeB alloys sintered by an electric field

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Yang, Yi; Lu, Dong; Huang, Kun-lan; Wang, Jun

    2012-11-01

    This study introduces a novel method of electric field sintering for preparing NdFeB magnets. NdFeB alloy compacts were all sintered by electric fields for 8 min at 1000°C with different preset heating rates. The characteristics of electric field sintering and the effects of heating rate on the sintering densification of NdFeB alloys were also studied. It is found that electric field sintering is a new non-pressure rapid sintering method for preparing NdFeB magnets with fine grains at a relatively lower sintering temperature and in a shorter sintering time. Using this method, the sintering temperature and process of the compacts can be controlled accurately. When the preset heating rate increasing from 5 to 2000°C/s the densification of NdFeB sintered compacts gradually improves. As the preset heating rate is 2000°C/s, Nd-rich phases are small, dispersed and uniformly distributed in the sintered compact, and the magnet has a better microstructure than that made by conventional vacuum sintering. Also, the maximum energy product of the sintered magnet reaches 95% of conventionally vacuum sintered magnets.

  1. Controlling the oxygen potential to improve the densification and the solid solution formation of uranium-plutonium mixed oxides

    NASA Astrophysics Data System (ADS)

    Berzati, Ségolène; Vaudez, Stéphane; Belin, Renaud C.; Léchelle, Jacques; Marc, Yves; Richaud, Jean-Christophe; Heintz, Jean-Marc

    2014-04-01

    Diffusion mechanisms occurring during the sintering of oxide ceramics are affected by the oxygen content of the atmosphere, as it imposes the nature and the concentration of structural defects in the material. Thus, the oxygen partial pressure, p(O2), of the sintering gas has to be precisely controlled, otherwise a large dispersion in various parameters, critical for the manufacturing of ceramics such as nuclear oxides fuels, is likely to occur. In the present work, the densification behaviour and the solid solution formation of a mixed uranium-plutonium oxide (MOX) were investigated. The initial mixture, composed of 70% UO2 + 30% PuO2, was studied at p(O2) ranging from 10-15 to 10-4 atm up to 1873 K both with dilatometry and in situ high temperature X-ray diffraction. This study has shown that the initial oxides UO2+x and PuO2-x first densify during heating and then the solid solution formation starts at about 200 K higher. The densification and the formation of the solid solution both occur at a lower temperature when p(O2) increases. Based on this result, it is possible to better define the sintering atmosphere, eventually leading to optimized parameters such as density, oxygen stoichiometry and cations homogenization of nuclear ceramics and of a wide range of industrial ceramic materials.

  2. Mechanism of densification in silica glass under pressure as revealed by a bottom-up pairwise effective interaction model

    NASA Astrophysics Data System (ADS)

    Izvekov, Sergei; Rice, Betsy M.

    2012-04-01

    A new short-range pairwise numerical potential for silica is presented. The potential is derived from a single ab initio molecular dynamics (AIMD) simulation of molten silica using the force-matching method with the forces being represented numerically by piecewise functions (splines). The AIMD simulation is performed using the Born-Oppenheimer method with the generalized gradient approximation (BLYP) for the XC energy functional. The new effective potential includes a soft-repulsive shoulder to describe the interactions of oxygen ions at short separations. The new potential, despite being short-ranged and derived from single-phase data, exhibits a good transferability to silica crystalline polymorphs and amorphous silica. The importance of the O-O soft-repulsive shoulder interaction on glass densification under cold and shock compressions is assessed from MD simulations of silica glass under room and shock Hugoniot conditions, respectively. Results from these simulations indicate that the appearance of oxygen complexes (primarily pairs) interacting through soft-repulsive shoulder potential occurs at 8-10 GPa, and under cold compression conditions becomes notable at 40 GPa, essentially coinciding with the transition to a Si sixfold coordination state. An analysis of changes in system structure in compressed and shocked states reveals that the O ions interacting through the soft-repulsive shoulder potential in denser states of silica glass may create a mechanical multi-stability under elevated pressures and thus to contribute to the observed anomalous densification.

  3. Liquid Oxygen Propellant Densification Unit Ground Tested With a Large-Scale Flight-Weight Tank for the X-33 Reusable Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Tomsik, Thomas M.

    2002-01-01

    Propellant densification has been identified as a critical technology in the development of single-stage-to-orbit reusable launch vehicles. Technology to create supercooled high-density liquid oxygen (LO2) and liquid hydrogen (LH2) is a key means to lowering launch vehicle costs. The densification of cryogenic propellants through subcooling allows 8 to 10 percent more propellant mass to be stored in a given unit volume, thereby improving the launch vehicle's overall performance. This allows for higher propellant mass fractions than would be possible with conventional normal boiling point cryogenic propellants, considering the normal boiling point of LO2 and LH2.

  4. Volcanic sintering and densification of glassy and crystalline ash: Kinetics, strength recovery and seismogenicity

    NASA Astrophysics Data System (ADS)

    Vasseur, J.; Wadsworth, F. B.; Lavallee, Y.; Hess, K.; Dingwell, D. B.

    2013-12-01

    consideration permitted us to explore the effect of sintering on the stress required for dynamic macroscopic failure of synthesized samples at conditions relevant to volcanic conduits. Sintering and densification results in a non linear increase in strength and micromechanical modelling shows that the pore-emanated crack model explains this trend as a function of pore fraction and size. We also assessed the ability of precursory microseismic signals to be used as a failure forecast proxy according to drastic changes in porosity (˜40 to 0%) and material strength (>100 MPa). Homogeneous single-phase liquids to heterogeneous multi-phase (pores in glasses, pores and crystals in other volcanic rocks) liquids display different microseismic patterns preceding bulk sample failure, somewhat mimicking the range of seismic precursory signals observed at volcanoes with magma of similar viscosity and mechanical characteristics. Defect-free glass for example will rapidly accumulate a huge amount of strain energy as it requires to exceed an elevated strength for failure (˜500-700 MPa) and suddenly release it via pervasing microfracturing. Associated microseismic acceleration will display almost no or very late forewarning and seismic-based failure prediction will be hard to make.

  5. Densification kinetics of glassy and crystalline volcanic ash and subsequent predictability associated with its fragmentation

    NASA Astrophysics Data System (ADS)

    Vasseur, Jeremie; Wadsworth, Fabian; Lavallée, Yan; Hess, Kai-Uwe; Dingwell, Donald

    2014-05-01

    consideration permitted us to explore the effect of sintering on the stress required for dynamic macroscopic failure of synthesized samples at conditions relevant to volcanic conduits. Sintering and densification results in a non linear increase in strength and micromechanical modelling shows that the pore-emanated crack model explains this trend as a function of pore fraction and size. We also assessed the ability of precursory microseismic signals to be used as a failure forecast proxy according to drastic changes in porosity (˜40 to 0%) and material strength (>102 MPa). Homogeneous single-phase liquids to heterogeneous multi-phase (pores in glasses, pores and crystals in other volcanic rocks) liquids display different microseismic patterns preceding bulk sample failure, somewhat mimicking the range of seismic precursory signals observed at volcanoes with magma of similar viscosity and mechanical characteristics. Defect-free glass for example will rapidly accumulate a huge amount of strain energy as it requires to exceed an elevated strength for failure (˜500-700 MPa) and suddenly release it via localised microfracturing. Microseismic acceleration associated with defect-poor rocks/magmas display trial or occasionally little forewarning with the implication that seismic-based failure prediction may be difficult to make in real-time monitoring.

  6. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  7. Simulation of the Densification of Semicrystalline Polymer Powders during the Selective Laser Sintering Process: Application to Nylon-12,

    SciTech Connect

    Dong, L.; Makradi, A.; Ahzi, Said; Remond, Y.; Sun, Xin

    2008-06-01

    The heating and densification processes of semi-crystalline polymer powders, during the selective laser sintering process, are simulated using the finite element method. Based on previously developed three-dimensional approach for the sintering of amorphous polymer powders, the modeling methodology is extended to semi-crystalline polymers by taking into account the effects of latent heat during melting. In these simulations, the temperature dependent thermal conductivity, specific heat, density and the effect of latent heat are computed then used as material constants for the integration of the heat equation. Results for temperature and density distribution using Nylon-12 powder are presented and discussed. The effects of processing parameters on the density distribution are also presented.

  8. Pressure-induced densification in GeO{sub 2} glass: A transmission x-ray microscopy study

    SciTech Connect

    Lin, Yu Zeng, Qiaoshi; Yang, Wenge; Mao, Wendy L.

    2013-12-23

    Nanoscale transmission x-ray microscopy measurements have been performed to determine the effect of pressure (P) on the volume (V) change in GeO{sub 2} glass up to 38.5 GPa. The P-V data show a continuous increase upon compression, indicating that the density-driven structural transformation is a gradual process. Over the pressure range studied, a transition is observed at approximately 10–13 GPa, where the material displays distinct compression behaviors. The pressure-induced densification that involves the coordination number change has been discussed. Using this newly developed high-pressure imaging technique with tens of nanometer resolution, we have provided a direct and unequivocal way for measuring density of amorphous materials to much higher pressures with accuracy rivaling x-ray diffraction of crystalline solids.

  9. Controllable film densification and interface flatness for high-performance amorphous indium oxide based thin film transistors

    SciTech Connect

    Ou-Yang, Wei E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Mitoma, Nobuhiko; Kizu, Takio; Gao, Xu; Lin, Meng-Fang; Tsukagoshi, Kazuhito E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Nabatame, Toshihide

    2014-10-20

    To avoid the problem of air sensitive and wet-etched Zn and/or Ga contained amorphous oxide transistors, we propose an alternative amorphous semiconductor of indium silicon tungsten oxide as the channel material for thin film transistors. In this study, we employ the material to reveal the relation between the active thin film and the transistor performance with aid of x-ray reflectivity study. By adjusting the pre-annealing temperature, we find that the film densification and interface flatness between the film and gate insulator are crucial for achieving controllable high-performance transistors. The material and findings in the study are believed helpful for realizing controllable high-performance stable transistors.

  10. The effect of volume phase changes, mass transport, sunlight penetration, and densification on the thermal regime of icy regoliths

    NASA Technical Reports Server (NTRS)

    Fanale, Fraser P.; Salvail, James R.; Matson, Dennis L.; Brown, Robert H.

    1990-01-01

    The present quantitative modeling of convective, condensational, and sublimational effects on porous ice crust volumes subjected to solar radiation encompasses the effect of such insolation's penetration of visible bandpass-translucent light, but opaque to the IR bandpass. Quasi-steady-state temperatures, H2O mass fluxes, and ice mass-density change rates are computed as functions of time of day and ice depth. When the effects of latent heat and mass transport are included in the model, the enhancement of near-surface temperature due to the 'solid-state greenhouse effect' is substantially diminished. When latent heat, mass transport, and densification effects are considered, however, a significant solid-state greenhouse effect is shown to be compatible with both morphological evidence for high crust strengths and icy shell decoupling from the lithosphere.

  11. Gravity induced densification of floating crude oil by granular materials: Effect of particle size and surface morphology.

    PubMed

    Boglaienko, Daria; Tansel, Berrin

    2016-06-15

    Densification and sedimentation of floating crude oil to the bottom of water column reduces the radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. Performances of different natural granular materials were evaluated for capturing efficiency of floating fresh South Louisiana crude oil. The granular materials studied were quartz sand with medium (20-30mesh) and fine (40-100mesh) particle size, limestone with coarse (4-10mesh) and medium (16-40mesh) particle size, beach sand (20-80mesh), and clay (kaolin with ferric oxide; passing 200mesh). Beach sand (mixture of quartz and limestone 20-80mesh) and limestone (16-40mesh) demonstrated better performance for capture, densification and submergence of the crude oil among the materials evaluated. The behavior of granular particles with the hydrophobic phase can be classified as (1) immersion entrapment inside the hydrophobic phase (slurry), and (2) partial encapsulation of the hydrophobic phase by a single layer of particles (raft). With crude oil, the particles were primarily entrapped within the hydrophobic phase. Study of the effect of particle size and morphology (i.e., porosity) of the granular materials on capture performance showed that average surface pore size did not have a significant effect on aggregation with oil, however, higher capture efficiency was observed with materials of higher surface porosity (beach sand and limestone). The experiments revealed that there is a critical particle size range (passing 10mesh) which resulted in more effective aggregation of the granular materials with crude oil.

  12. Solid-State Densification of Spun-Cast Self-Assembled Monolayers for Use in Ultra-Thin Hybrid Dielectrics

    PubMed Central

    Hutchins, Daniel O.; Acton, Orb; Weidner, Tobias; Cernetic, Nathan; Baio, Joe E.; Castner, David G.; Ma, Hong; Jen, Alex K.-Y.

    2013-01-01

    Ultra-thin self-assembled monolayer (SAM)-oxide hybrid dielectrics have gained significant interest for their application in low-voltage organic thin film transistors (OTFTs). A [8-(11-phenoxy-undecyloxy)-octyl]phosphonic acid (PhO-19-PA) SAM on ultrathin AlOx (2.5 nm) has been developed to significantly enhance the dielectric performance of inorganic oxides through reduction of leakage current while maintaining similar capacitance to the underlying oxide structure. Rapid processing of this SAM in ambient conditions is achieved by spin coating, however, as-cast monolayer density is not sufficient for dielectric applications. Thermal annealing of a bulk spun-cast PhO-19-PA molecular film is explored as a mechanism for SAM densification. SAM density, or surface coverage, and order are examined as a function of annealing temperature. These SAM characteristics are probed through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS). It is found that at temperatures sufficient to melt the as-cast bulk molecular film, SAM densification is achieved; leading to a rapid processing technique for high performance SAM-oxide hybrid dielectric systems utilizing a single wet processing step. To demonstrate low-voltage devices based on this hybrid dielectric (with leakage current density of 7.7×10−8 A cm−2 and capacitance density of 0.62 µF cm−2 at 3 V), pentacene thin-film transistors (OTFTs) are fabricated and yield sub 2 V operation and charge carrier mobilites of up to 1.1 cm2 V−1 s−1. PMID:24288423

  13. Firn density profile at Megadunes, East Antarctica, calls for an improved densification model for low accumulation sites.

    NASA Astrophysics Data System (ADS)

    Suwa, M.; Severinghaus, J. P.

    2004-12-01

    We report a density profile of the firn at Megadunes, East Antarctica (80o78'S; 124o50'E). The Megadunes site is characterized by a low mass accumulation rate (2.9 g/cm2/yr) and cold temperature (mean annual = -49.5oC). Validating existing firn densification models using a density profile of such a site is important because such models, either purely empirical or mechanistic, have been calibrated with few sites that are analogous to a glacial condition (ultralow accumulation and temperature). We make use of CO2 concentrations in the lock-in (or non-diffusive) zone to obtain the accumulation rate, assuming that the gas in the lock-in zone ages at the same rate as the surrounding ice [Battle et al., 1996], and assuming that the gas enclosure rate must equal the long-term mean accumulation rate. This estimate is preliminary and may change when results from beta analysis of cores become available. Our density profile shows that the widely used pure empirical model by Herron and Langway [1980] overestimates the close-off depth by 16 %, and the semi-mechanistic model by Pimienta and Barnola [Barnola et al., 1991] also overestimates the close-off depth by 26 %. Our study at the Megadunes site indicates that the δ 15N of N2 paradox for glacial ice from East Antarctica would have partly resulted from a poorly calibrated densification model for a `glacial-like' condition and a thick convective zone as we observed at the Megadunes site [Severinghaus et al., in prep].

  14. Formulation, Pretreatment, and Densification Options to Improve Biomass Specifications for Co-Firing High Percentages with Coal

    SciTech Connect

    Jaya Shankar Tumuluru; J Richard Hess; Richard D. Boardman; Shahab Sokhansanj; Christopher T. Wright; Tyler L. Westover

    2012-06-01

    There is a growing interest internationally to use more biomass for power generation, given the potential for significant environmental benefits and long-term fuel sustainability. However, the use of biomass alone for power generation is subject to serious challenges, such as feedstock supply reliability, quality, and stability, as well as comparative cost, except in situations in which biomass is locally sourced. In most countries, only a limited biomass supply infrastructure exists. Alternatively, co-firing biomass alongwith coal offers several advantages; these include reducing challenges related to biomass quality, buffering the system against insufficient feedstock quantity, and mitigating the costs of adapting existing coal power plants to feed biomass exclusively. There are some technical constraints, such as low heating values, low bulk density, and grindability or size-reduction challenges, as well as higher moisture, volatiles, and ash content, which limit the co-firing ratios in direct and indirect co-firing. To achieve successful co-firing of biomass with coal, biomass feedstock specifications must be established to direct pretreatment options in order to modify biomass materials into a format that is more compatible with coal co-firing. The impacts on particle transport systems, flame stability, pollutant formation, and boiler-tube fouling/corrosion must also be minimized by setting feedstock specifications, which may include developing new feedstock composition by formulation or blending. Some of the issues, like feeding, co-milling, and fouling, can be overcome by pretreatment methods including washing/leaching, steam explosion, hydrothermal carbonization, and torrefaction, and densification methods such as pelletizing and briquetting. Integrating formulation, pretreatment, and densification will help to overcome issues related to physical and chemical composition, storage, and logistics to successfully co-fire higher percentages of biomass ( > 40

  15. Firn densification in a Late Noachian “icy highlands” Mars: Implications for ice sheet evolution and thermal response

    NASA Astrophysics Data System (ADS)

    Cassanelli, James P.; Head, James W.

    2015-06-01

    Recent modeling of a thicker early CO2 martian atmosphere and Late Noachian climate predicts that for pressures beyond a fraction of a bar, atmosphere-surface thermal coupling occurs, resulting in adiabatic cooling of high areas across Mars. This promotes the transport of water ice from relatively warmer low-lying areas to the highlands, where deposition and accumulation of water ice result in an "icy highlands" Late Noachian Mars. Deposits will remain stable in the highlands under nominal Late Noachian conditions, but the potential exists for punctuated heating by both top-down (e.g. impacts, volcanism) and bottom-up (e.g. elevated geothermal heat flux) processes. Important in understanding melt generation from these processes is the state of the accumulated snow and ice. Through modeling of the firn densification process in the "icy highlands" framework we assess: (1) the nature of snow accumulation and the physical growth and evolution of the predicted ice deposits, and (2) the implications for the thermal properties of the ice sheets and the response to heating events. Analysis of the firn densification process in the "icy highlands" context indicates that: (1) the upper layers of the ice sheet will be more vulnerable to melting from top-down heating processes because they are comprised of the least dense and least thermally conductive ice, and (2) even with a low thermal conductivity firn layer, basal melting is only likely to occur through a combination of top-down and bottom-up heating. This is because at the nominal mean annual surface temperatures and estimated effective thermal conductivities, the predicted ice sheet thicknesses do not produce enough basal warming to initiate melting for plausible geothermal heat fluxes. Variations in spin-axis/orbital parameters alone are not predicted to cause widespread ablation (melting and sublimation) of the icy highlands ice sheets.

  16. Gravity induced densification of floating crude oil by granular materials: Effect of particle size and surface morphology.

    PubMed

    Boglaienko, Daria; Tansel, Berrin

    2016-06-15

    Densification and sedimentation of floating crude oil to the bottom of water column reduces the radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. Performances of different natural granular materials were evaluated for capturing efficiency of floating fresh South Louisiana crude oil. The granular materials studied were quartz sand with medium (20-30mesh) and fine (40-100mesh) particle size, limestone with coarse (4-10mesh) and medium (16-40mesh) particle size, beach sand (20-80mesh), and clay (kaolin with ferric oxide; passing 200mesh). Beach sand (mixture of quartz and limestone 20-80mesh) and limestone (16-40mesh) demonstrated better performance for capture, densification and submergence of the crude oil among the materials evaluated. The behavior of granular particles with the hydrophobic phase can be classified as (1) immersion entrapment inside the hydrophobic phase (slurry), and (2) partial encapsulation of the hydrophobic phase by a single layer of particles (raft). With crude oil, the particles were primarily entrapped within the hydrophobic phase. Study of the effect of particle size and morphology (i.e., porosity) of the granular materials on capture performance showed that average surface pore size did not have a significant effect on aggregation with oil, however, higher capture efficiency was observed with materials of higher surface porosity (beach sand and limestone). The experiments revealed that there is a critical particle size range (passing 10mesh) which resulted in more effective aggregation of the granular materials with crude oil. PMID:26971215

  17. Synthesis of MgO-CaO-Al2O3-SiO2 nanocomposite powder by polymeric complex method as a novel sintering additive of AlN ceramics

    NASA Astrophysics Data System (ADS)

    Lee, Hwa-Jun; Cho, Woo-Seok; Kim, Hyeong Jun; Pan, Wei; Shahid, Mohammad; Ryu, Sung-Soo

    2016-09-01

    A MgO-CaO-Al2O3-SiO2 (MCAS) nanocomposite powder with a particle size of 50 nm and a specific surface area of 40.6 m2/g was successfully synthesized via heat-treatment of polymeric precursors containing Mg, Ca, Al and Si in air at 700 °C for 5 h. It was characterized as a novel sintering additive for the densification AlN ceramics at a low temperature below 1600 °C. It was found that the nanosized MCAS powder was suitable for the densification of AlN ceramics. In particular, full densification could be achieved when only 1.0 wt% MCAS additive-doped AlN powder compact was sintered for 1 h at 1600 °C, and a thermal conductivity of 84 W/m·K was attained.

  18. Consolidation of Si3N4 without additives (by hot isostatic pressing)

    NASA Technical Reports Server (NTRS)

    Yeh, H. C.

    1983-01-01

    The potential of using hot isostatic pressing (HIP'ing) technique to produce dense silicon nitride materials without or with a reduced amount of additives (much less than 5 w/o) was investigated. Hot isostatic pressing technique can provide higher pressure and temperature than hot pressing can, thus has the potential of requiring less densification aids to consolidate Si3N4 materials. It was anticipated that if such dense materials could be fabricated, the high temperature strength of the material should be improved significantly. Observations on the phase transformation, densification behavior, and microstructures of the samples are also documented. Density, microhardness, four point bend strength (room temperature and 1370 C) were measured on selected densified materials.

  19. Phosphazene additives

    DOEpatents

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  20. Potlining Additives

    SciTech Connect

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  1. Network cation coordination in aluminoborosilicate and Mg- aluminosilicate glasses: pressure effects in recovered structural changes and densification

    NASA Astrophysics Data System (ADS)

    Bista, S.; Stebbins, J. F.; Sisson, T. W.; Hankins, W. B.

    2015-12-01

    In this study, we compare the aluminum and boron coordination of glass samples recovered from piston-cylinder experiments carried out at 1 to 3 GPa and near to their ambient glass transition temperature (Tg), which we have found gives a more accurate picture of high pressure structural changes than experiments involving quenching from above the liquidus, as large pressure drops can occur in the latter. Aluminoborosilicate glasses with excess modifier (Ca, La and Y- aluminoborosilicate) quenched from melts at 1-3 GPa were studied with B-11 and Al-27 MAS NMR to assess relative effects on two different network cations. Structural changes in the Y-aluminoborosilicate are dramatic, going from mostly AlO4 at low pressure to mostly AlO5 and AlO6 at 3 GPa. Large increases in BO4 (vs. BO3) are also seen. Mg-aluminosilicate glasses, both tectosilicate (Mg2Al4Si6O20) and with excess modifier composition (Mg3Al2Si6O18) quenched from melts at 1-3 GPa pressure were studied with Al-27 MAS NMR. In contrast to our previous study (Bista et al., Am. Min., in press) of jadeite glass, where only 0.5% of fivefold aluminum was seen in glass recovered from 3 GPa, five and six fold aluminum species increase significantly with increasing pressure in both Mg aluminosilicate glass compositions studied here. We observe that the tectosilicate Mg aluminosilicate glass has more higher coordinated aluminum than the excess modifier containing composition in the pressure range in our study. In the previous study (Bista et al., in press) of jadeite and calcium aluminosilicate (Ca3Al2Si6O18) glasses, 6-8% densification was observed in glasses recovered from 3 GPa. In this study of Mg aluminosilicate glasses, we observe 12% densification in glasses recovered from 3 GPa. Both types of observation confirm that structural and density changes with pressure are enhanced by higher field strength modifier cations, and will be especially important in Mg- and Fe-rich mantle melts.

  2. Effects of selenization conditions on densification of Cu(In,Ga)Se2 (CIGS) thin films prepared by spray deposition of CIGS nanoparticles

    NASA Astrophysics Data System (ADS)

    Ahn, SeJin; Kim, Ki Hyun; Yun, Jae Ho; Yoon, Kyung Hoon

    2009-06-01

    Spray deposited porous CIGS nanoparticle-derived thin films were selenized in a two zone rapid thermal annealing furnace and effects of various selenization parameters including Se evaporation temperature, flow rate of carrier gas, and substrate temperature on densification of the CIGS layers were investigated. It was found that higher Se supply to CIGS nanoparticles either by increasing Se evaporation temperature or by increasing the flow rate of carrier gas resulted in larger CIGS grains with higher degree of crystallinity, while it also induced formation of a thicker MoSe2 layer in-between CIGS and Mo which resulted in partial detachment of CIGS/MoSe2/Mo layers from the glass substrate. Densification of CIGS layer by growth of nanoparticles and formation of thick MoSe2 were explained by a liquid Se assisted reaction rather than by a vapor phase Se assisted reaction.

  3. Understanding the densification process of Bi2Sr2CaCu2O x round wires with overpressure processing and its effect on critical current density

    NASA Astrophysics Data System (ADS)

    Matras, M. R.; Jiang, J.; Larbalestier, D. C.; Hellstrom, E. E.

    2016-10-01

    Overpressure (OP) processing increases the critical current density ({{\\boldsymbol{J}}}{{C}}) of Bi2Sr2CaCu2O x (2212) round wires by shrinking the surrounding Ag matrix around the 2212 filaments, driving them close to full density and greatly increasing the 2212 grain connectivity. Indeed densification is vital for attaining the highest {{\\boldsymbol{J}}}{{C}}. Here, we investigate the time and temperature dependence of the wire densification. We find that the wire diameter decreases by 3.8 ± 0.3% after full heat treatment at 50 atm and 100 atm OP. At 50 atm OP pressure, the filaments start densifying above 700 °C and reach a 3.30 ± 0.07% smaller diameter after 2 h at 820 °C, which is below the melting point of 2212 powder. The densification is homogeneous and does not change the filament shape before melting. The growth of non-superconducting phases is observed at 820 °C, suggesting that time should be minimized at high temperature prior to melting the 2212 powder. Study of an open-ended 2.2 m long wire sample shows that full densification and the high OP {{\\boldsymbol{J}}}{{C}} ({{\\boldsymbol{J}}}{{C}} varies by about 3.1 times over the 2.2 m long wire) is reached about 1 m from the open ends, thus showing that coil-length wires can be protected from leaky seals by adding at least 1 m of sacrificial wire at each end.

  4. Influence of processing parameters on laser penetration depth and melting/re-melting densification during selective laser melting of aluminum alloy

    NASA Astrophysics Data System (ADS)

    Yu, Guanqun; Gu, Dongdong; Dai, Donghua; Xia, Mujian; Ma, Chenglong; Chang, Kun

    2016-10-01

    A three-dimensional mesoscopic model, considering the powder-to-solid transition, motion of gas bubbles within molten pool and the effect of surface tension, has been established in order to investigate the evolution rule of pores and re-melting densification mechanism during selective laser melting of AlSi10Mg. The results indicated that re-melting phenomenon of previous fabricated layer induced by laser melting of current powder layer played a crucial role on the increase in densification rate. During the re-melting process, the trapped gas pores in previous layer rose up swiftly and came to the surface consequently, resulting in remarkably elevated densification in previous layer. The influences of laser scan speed on the single-track morphology, types of pores and laser penetration depth have also been studied. It showed that the maximum re-melting depth (31 µm) was attained, and meanwhile, pores left in preceding layer got eliminated completely due to the mass transfer within molten pool, when an appropriate laser scan speed (150 mm/s) was applied. In this case, reasonable laser energy per unit length and irradiation time tended to enhance the laser penetration depth for powder bed and decrease the porosity in as-fabricated layer. A series of experimental study were performed to verify the reliability of the above mesoscopic simulation, including the surface topography of single track and the types of pores. The redistribution of bubbles between the adjacent layers as well as the localized re-melting densification, which were observed from the longitudinal section of samples, was in good agreement with simulation results.

  5. YAG laser surface densification of a zircon refractory by adding AlN nanoparticles

    SciTech Connect

    Wang, W.Y.; Wang, A.H. . E-mail: pmahwang@public.wh.hb.cn; Zeng, D.W.; Bai, Z.K.; Xie, C.S.; Song, W.L.; Zhu, X.C.

    2006-04-15

    A zircon refractory zirconium silicate was surface melted with a pulsed YAG laser to introduce AlN nanoparticles, with the aim of improving its surface density and modifying the corresponding microstructure. The microstructure and phase structure features of the refractory induced by the laser beam were studied by scanning transmission microscopy, incorporating energy dispersive X-ray and X-ray diffraction analysis. Results show that the addition of AlN nanoparticles into the refractory surface significantly reduced the laser beam energy required to melt the surface of the refractory. The laser-melted depth was increased with an increase of laser power from 133 to 200 W. The microstructure of the laser-treated zone with the addition of AlN nanoparticles has a much finer dendritic structure with undeveloped primary dendrite arms while without the addition of AlN nanoparticles, a coarser dendrite with much long primary dendrite arms was observed. The phase structure of the laser-treated layer with the addition of AlN nanoparticles was found to be composed of m-ZrO{sub 2}, c-ZrO{sub 2}, ZrSiO{sub 4} and H-AlN.

  6. Enhanced Densification of Carbonyl Iron Powder Compacts by the Retardation of Exaggerated Grain Growth through the Use of High Heating Rates

    NASA Astrophysics Data System (ADS)

    Hwang, Kuen-Shyang; Lu, Yung-Chung; Shu, Guo-Jiun; Chen, Bor-Yuan

    2009-12-01

    An investigation of the effect of heating rates on the densification behavior of carbonyl iron powder compacts, particularly on the exaggerated grain growth during the α- γ phase transformation, was carried out in this study. Compacts heated at 1200 °C/min and then sintered for 90 minutes at 1200 °C attained 7.14 g/cm3, while those heated at 10 °C/min reached only 6.61 g/cm3. Dilatometer curves using heating rates of 2 °C/min, 5 °C/min, 10 °C/min, 30 °C/min, and 90 °C/min demonstrate that 90 °C/min yields the highest sintered density. The microstructure analysis shows that high heating rates inhibit exaggerated grain growth during the phase transformation by keeping the interparticle neck size small and pinning the grain boundaries. This explanation is supported by the calculation that shows that the energy barrier preventing the grain boundary from breaking away from the neck is reduced hyperbolically as the neck size and the amount of shrinkage increase. The high heating rate, however, shows little beneficial effect for materials that have no allotropic phase transformation or have less drastic grain growth during heating, such as nickel and copper. Thus, bypassing the low temperatures to suppress the surface diffusion mechanism, which does not contribute to densification, is ruled out as the main reason for the enhanced densification of carbonyl iron powders.

  7. Liquid Oxygen Propellant Densification Production and Performance Test Results With a Large-Scale Flight-Weight Propellant Tank for the X33 RLV

    NASA Technical Reports Server (NTRS)

    Tomsik, Thomas M.; Meyer, Michael L.

    2010-01-01

    This paper describes in-detail a test program that was initiated at the Glenn Research Center (GRC) involving the cryogenic densification of liquid oxygen (LO2). A large scale LO2 propellant densification system rated for 200 gpm and sized for the X-33 LO2 propellant tank, was designed, fabricated and tested at the GRC. Multiple objectives of the test program included validation of LO2 production unit hardware and characterization of densifier performance at design and transient conditions. First, performance data is presented for an initial series of LO2 densifier screening and check-out tests using densified liquid nitrogen. The second series of tests show performance data collected during LO2 densifier test operations with liquid oxygen as the densified product fluid. An overview of LO2 X-33 tanking operations and load tests with the 20,000 gallon Structural Test Article (STA) are described. Tank loading testing and the thermal stratification that occurs inside of a flight-weight launch vehicle propellant tank were investigated. These operations involved a closed-loop recirculation process of LO2 flow through the densifier and then back into the STA. Finally, in excess of 200,000 gallons of densified LO2 at 120 oR was produced with the propellant densification unit during the demonstration program, an achievement that s never been done before in the realm of large-scale cryogenic tests.

  8. Zirconium Carbide Produced by Spark Plasma Sintering and Hot Pressing: Densification Kinetics, Grain Growth, and Thermal Properties

    DOE PAGESBeta

    Wei, Xialu; Back, Christina; Izhvanov, Oleg; Haines, Christopher; Olevsky, Eugene

    2016-07-14

    Spark plasma sintering (SPS) has been employed to consolidate a micron-sized zirconium carbide (ZrC) powder. ZrC pellets with a variety of relative densities are obtained under different processing parameters. The densification kinetics of ZrC powders subjected to conventional hot pressing and SPS are comparatively studied by applying similar heating and loading profiles. Due to the lack of electric current assistance, the conventional hot pressing appears to impose lower strain rate sensitivity and higher activation energy values than those which correspond to the SPS processing. A finite element simulation is used to analyze the temperature evolution within the volume of ZrCmore » specimens subjected to SPS. The control mechanism for grain growth during the final SPS stage is studied via a recently modified model, in which the grain growth rate dependence on porosity is incorporated. Finally, the constant pressure specific heat and thermal conductivity of the SPS-processed ZrC are determined to be higher than those reported for the hot-pressed ZrC and the benefits of applying SPS are indicated accordingly.« less

  9. Mass densification and defect restoration in chemical vapor deposition silicon dioxide film using Ar plasma excited by microwave

    SciTech Connect

    Kawase, Kazumasa Motoya, Tsukasa; Uehara, Yasushi; Teramoto, Akinobu; Suwa, Tomoyuki; Ohmi, Tadahiro

    2014-09-01

    Silicon dioxide (SiO{sub 2}) films formed by chemical vapor deposition (CVD) have been treated with Ar plasma excited by microwave. The changes of the mass densities, carrier trap densities, and thicknesses of the CVD-SiO{sub 2} films with the Ar plasma treatments were investigated. The mass density depth profiles were estimated with X-Ray Reflectivity (XRR) analysis using synchrotron radiation. The densities of carrier trap centers due to defects of Si-O bond network were estimated with X-ray Photoelectron Spectroscopy (XPS) time-dependent measurement. The changes of the thicknesses due to the oxidation of Si substrates were estimated with the XRR and XPS. The mass densities of the CVD-SiO{sub 2} films are increased by the Ar plasma treatments. The carrier trap densities of the films are decreased by the treatments. The thicknesses of the films are not changed by the treatments. It has been clarified that the mass densification and defect restoration in the CVD-SiO{sub 2} films are caused by the Ar plasma treatments without the oxidation of the Si substrates.

  10. Revisiting Dosing Regimen Using Pharmacokinetic/Pharmacodynamic Mathematical Modeling: Densification and Intensification of Combination Cancer Therapy.

    PubMed

    Meille, Christophe; Barbolosi, Dominique; Ciccolini, Joseph; Freyer, Gilles; Iliadis, Athanassios

    2016-08-01

    Controlling effects of drugs administered in combination is particularly challenging with a densified regimen because of life-threatening hematological toxicities. We have developed a mathematical model to optimize drug dosing regimens and to redesign the dose intensification-dose escalation process, using densified cycles of combined anticancer drugs. A generic mathematical model was developed to describe the main components of the real process, including pharmacokinetics, safety and efficacy pharmacodynamics, and non-hematological toxicity risk. This model allowed for computing the distribution of the total drug amount of each drug in combination, for each escalation dose level, in order to minimize the average tumor mass for each cycle. This was achieved while complying with absolute neutrophil count clinical constraints and without exceeding a fixed risk of non-hematological dose-limiting toxicity. The innovative part of this work was the development of densifying and intensifying designs in a unified procedure. This model enabled us to determine the appropriate regimen in a pilot phase I/II study in metastatic breast patients for a 2-week-cycle treatment of docetaxel plus epirubicin doublet, and to propose a new dose-ranging process. In addition to the present application, this method can be further used to achieve optimization of any combination therapy, thus improving the efficacy versus toxicity balance of such a regimen.

  11. A GPS Network Densification in Saudi Arabia in Support of Geophysical Investigations in the Region

    NASA Astrophysics Data System (ADS)

    Almuslmani, B.; Al-Motari, E.; Bingley, R. M.; Teferle, F. N.; Moore, T.

    2006-12-01

    Current investigations of the motions of the Arabian and its neighboring plates are primarily based on GPS measurements obtained in the surrounding areas of the Arabian plate, with few stations actually located on the Arabian plate itself in the Kingdom of Saudi Arabia. In order to advance the knowledge of the dynamics of the Arabian plate and its intra-plate deformations, the General Directorate of Military Survey (GDMS), through a collaboration with the Institute of Engineering Surveying and Space Geodesy (IESSG), densified the GPS network in Saudi Arabia, covering nearly two thirds of the tectonic plate. Since July 2002, a network of 32 GPS stations has been established at locations of the Saudi Arabia geodetic network. At all of these GPS stations a concrete pillar has been used as the monument and the locations have been selected in order to give the broadest distribution of observing sites. During 2005, 27 additional GPS stations in the Hejaz and Asser Mountains in the south-western part of Saudi Arabia, have been established, with the GDMS GPS network now comprising a total of 59 stations. In this presentation we will introduce the new GPS network in Saudi Arabia established by GDMS and will present the initial results from campaigns in March 2003 and March 2005. We show preliminary estimates of absolute and relative Arabian plate motions inferred from the GPS network and a detailed comparison of the results based on the Bernese GPS software versions 4.2 and 5.0.

  12. Effects of acetylacetone additions on PZT thin film processing

    SciTech Connect

    Schwartz, R.W.; Assink, R.A.; Dimos, D.; Sinclair, M.B.; Boyle, T.J.; Buchheit, C.D.

    1995-02-01

    Sol-gel processing methods are frequently used for the fabrication of lead zirconate titanate (PZT) thin films for many electronic applications. Our standard approach for film fabrication utilizes lead acetate and acetic acid modified metal alkoxides of zirconium and titanium in the preparation of our precursor solutions. This report highlights some of our recent results on the effects of the addition of a second chelating ligand, acetylacetone, to this process. The authors discuss the changes in film drying behavior, densification and ceramic microstructure which accompany acetylacetone additions to the precursor solution and relate the observed variations in processing behavior to differences in chemical precursor structure induced by the acetylacetone ligand. Improvements in thin film microstructure, ferroelectric and optical properties are observed when acetylacetone is added to the precursor solution.

  13. Study of Material Densification of In718 in the Higher Throughput Parameter Regime

    NASA Technical Reports Server (NTRS)

    Cordner, Samuel

    2016-01-01

    Selective Laser Melting (SLM) is a powder bed fusion additive manufacturing process used increasingly in the aerospace industry to reduce the cost, weight, and fabrication time for complex propulsion components. Previous optimization studies for SLM using the Concept Laser M1 and M2 machines at NASA Marshall Space Flight Center have centered on machine default parameters. The objective of this project is to characterize how heat treatment affects density and porosity from a microscopic point of view. This is performs using higher throughput parameters (a previously unexplored region of the manufacturing operating envelope for this application) on material consolidation. Density blocks were analyzed to explore the relationship between build parameters (laser power, scan speed, and hatch spacing) and material consolidation (assessed in terms of density and porosity). The study also considers the impact of post-processing, specifically hot isostatic pressing and heat treatment, as well as deposition pattern on material consolidation in the higher energy parameter regime. Metallurgical evaluation of specimens will also be presented. This work will contribute to creating a knowledge base (understanding material behavior in all ranges of the AM equipment operating envelope) that is critical to transitioning AM from the custom low rate production sphere it currently occupies to the world of mass high rate production, where parts are fabricated at a rapid rate with confidence that they will meet or exceed all stringent functional requirements for spaceflight hardware. These studies will also provide important data on the sensitivity of material consolidation to process parameters that will inform the design and development of future flight articles using SLM.

  14. Cryogenic Propellant Densification Study

    NASA Technical Reports Server (NTRS)

    Ewart, R. O.; Dergance, R. H.

    1978-01-01

    Ground and vehicle system requirements are evaluated for the use of densified cryogenic propellants in advanced space transportation systems. Propellants studied were slush and triple point liquid hydrogen, triple point liquid oxygen, and slush and triple point liquid methane. Areas of study included propellant production, storage, transfer, vehicle loading and system requirements definition. A savings of approximately 8.2 x 100,000 Kg can be achieved in single stage to orbit gross liftoff weight for a payload of 29,484 Kg by utilizing densified cryogens in place of normal boiling point propellants.

  15. Effects of Powder Attributes and Laser Powder Bed Fusion (L-PBF) Process Conditions on the Densification and Mechanical Properties of 17-4 PH Stainless Steel

    NASA Astrophysics Data System (ADS)

    Irrinki, Harish; Dexter, Michael; Barmore, Brenton; Enneti, Ravi; Pasebani, Somayeh; Badwe, Sunil; Stitzel, Jason; Malhotra, Rajiv; Atre, Sundar V.

    2016-03-01

    The effects of powders attributes (shape and size distribution) and critical processing conditions (energy density) on the densification and mechanical properties of laser powder bed fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength and hardness of both water- and gas-atomized powders increased with increased energy density. Gas-atomized powders showed superior densification and mechanical properties when processed at low energy densities. However, the % theoretical density and mechanical properties of water-atomized powders were comparable to gas-atomized powders when sintered at a high energy density of 104 J/mm3. An important result of this study was that, even at high % theoretical density (97% ± 1%), the properties of as-printed parts could vary over a relatively large range (UTS: 500-1100 MPa; hardness: 25-39 HRC; elongation: 10-25%) depending on powder characteristics and process conditions. The results also demonstrate the feasibility of using relatively inexpensive water-atomized powders as starting raw material instead of the typically used gas-atomized powders to fabricate parts using L-PBF techniques by sintering at high energy densities.

  16. The Impact of Densification by Means of Informal Shacks in the Backyards of Low-Cost Houses on the Environment and Service Delivery in Cape Town, South Africa

    PubMed Central

    Govender, Thashlin; Barnes, Jo M.; Pieper, Clarissa H.

    2011-01-01

    This paper investigates the state-sponsored low cost housing provided to previously disadvantaged communities in the City of Cape Town. The strain imposed on municipal services by informal densification of unofficial backyard shacks was found to create unintended public health risks. Four subsidized low-cost housing communities were selected within the City of Cape Town in this cross-sectional survey. Data was obtained from 1080 persons with a response rate of 100%. Illegal electrical connections to backyard shacks that are made of flimsy materials posed increased fire risks. A high proportion of main house owners did not pay for water but sold water to backyard dwellers. The design of state-subsidised houses and the unplanned housing in the backyard added enormous pressure on the existing municipal infrastructure and the environment. Municipal water and sewerage systems and solid waste disposal cannot cope with the increased population density and poor sanitation behaviour of the inhabitants of these settlements. The low-cost housing program in South Africa requires improved management and prudent policies to cope with the densification of state-funded low-cost housing settlements. PMID:21695092

  17. Fabrication of Silica Glass from Rice Husk Ash with Spodumene Additions

    NASA Astrophysics Data System (ADS)

    Wasanapiarnpong, T.; Vorajesdarom, B.; Rujirakamort, E.; Nilpairach, S.; Mongkolkachit, C.

    2011-10-01

    Silica glass is an interesting material due to its low thermal expansion coefficient, high chemical inertness, and transparency. In this study, low cost rice husk ash waste containing mainly amorphous silica phase was used as a starting raw material. Formation of cristrobalite caused product damage during cooling down was suppressed by an addition of some sintering aids. Spodumene was selected to use as the sintering aid due to its ability to promote the sinterability of the rice husk ash by liquid phase forming. Lithium carbonate and aluminum nitrate were mixed with the rice husk ash as starting chemicals for spodumene forming. To investigate the effects of spodumene addition on densification, physical properties and thermal expansion coefficient, 25 and 50 mass% of spdumene were added to the mixture. Mixed powders were dry pressed into pellet shapes and sintered at 1000-1250 °C for 30 min in an electric furnace. It was found that 50 mass% addition of spodumene enhanced the densification of the specimens sintered at the temperature higher than 1250 °C. Water absorption was reduced to 1.11 % with bulk density of 2.12 g/cm3. Low thermal expansion coefficient of 2.70×10-6 /°C was achieved with only the petalite phase detection.

  18. Effect of powder characteristics on gas-pressure sintering of Si{sub 3}N{sub 4} with rare earth additives

    SciTech Connect

    Tiegs, T.N.; Nunn, S.D.; Walls, C.A.; Barker, D.; Davisson, C.; Jones, P.J.

    1993-09-01

    Several Si{sub 3}N{sub 4} powders, synthesized by various methods and having different surface areas, oxygen contents and impurity levels, were examined. During early stage densification, all powders showed similar shrinkage with the diimide ederived powder exhibiting delayed {alpha}/{beta} transformation compared to the other powders. The diimide and gas-phase derived powders achieved the highest final densities. Improved densification was observed by increasing the oxygen content and this also resulted in high toughness for some materials with rare earth apatite additives. However, the increased oxygen resulted in reduced high temperature strength. Fracture toughnesses (K{sub Ic}) up to 10 MPa{radical}m were obtained for some compositions.

  19. A {sup 11}B and {sup 7}Li MAS-NMR study of sol-gel lithium triborate glass subjected to thermal densification

    SciTech Connect

    Mustarelli, P.; Quartarone, E.; Benevelli, F.

    1997-06-01

    The effects of thermal densification on a sol-gel lithium triborate glass have been studied by {sup 11}B and {sup 7}Li NMR both static and at the magic angle (MAS). {sup 11}B spectra show that the boron average coordination is similar in sol-gel and melt-quenched samples and it does not change upon annealing. {sup 7}Li T{sub 1} is shorter ({approximately}8.5 s) in sol-gel glass as prepared than in its melt-quenched counterpart ({approximately}13 s) due to dipolar-dipolar Li-H interaction. {sup 7}Li longitudinal relaxation behavior captures a part of a complex devitrification process which is driven by the loss of both residual solvent and moisture.

  20. A comparison study on the densification behavior and mechanical properties of gelcast vs conventionally formed B{sub 4}C sintered conventionally and by microwaves

    SciTech Connect

    Menchhofer, P.A.; Kiggans, J.O.; Morrow, M.S.; Schechter, D.E.

    1996-06-01

    The utilization of microwave energy for reaching high temperatures necessary to densify B{sub 4}C powder is compared with conventional means of sintering by evaluating the mechanical properties after densification. Microwave energy has been shown to be an effective means for achieving high sintered densities, even though temperatures of {approximately} 2,250 C are required. In this study, green preforms of B{sub 4}C specimens were sintered by both conventional and microwave heating. This study also utilized an advanced forming method called ``Gelcasting`` developed at ORNL. Gelcasting is a fluid forming process whereby high solids suspensions of powders containing dissolved monomers are cast into a mold, then polymerized or ``gelled`` in situ. This investigation compares microstructures and mechanical properties of both Gelcast B{sub 4}C and ``conventionally`` die-pressed B{sub 4}C. The microstructures and final mechanical properties of B{sub 4}C specimens are discussed.

  1. Effect of hot pressing additives on the leachability of hot pressed sodium hydrous titanium oxide

    SciTech Connect

    Valentine, T.M.; Sambell, R.A.J.

    1980-01-01

    Sodium hydrous titanium oxide is an ion exchange resin which can be used for immobilizing medium level waste (MLW) liquors. When hot pressed, it undergoes conversion to a ceramic. Three low melting point materials (borax, bismuth trioxide, and a mixture of PbO/CuO) were added to the (Na)HTiO and the effect that each of these had on aiding densification was assessed. Hot pressing temperature, applied pressure, and percentage addition of hot pressing aid were varied. Percentage open porosity, flexural strength, and leachability were measured. There was a linear relationship between the percentage open porosity and the logarithm of the leach rate for a constant percentage addition of each additive.

  2. The effect of dielectric properties of sintering additives on microwave sintered silicon nitride ceramics.

    PubMed

    Chockalingam, Sreekumar; George, Jacob; Earl, David; Amarakoon, Vasantha R W

    2008-01-01

    Silicon nitride requires the use of susceptive additives for microwave liquid phase sintering due to the material's low dielectric loss. In this article, we report the effect of complex dielectric properties of two compositions of sintering aids on 2.45 GHz microwave sintered Si3N4 with respect to power absorption, temperature distribution and densification behavior. The temperature dependent dielectric properties were measured from 25 degrees C to 1400 degrees C using a conventional cavity perturbation technique. Finite Difference Time Domain (FDTD) electromagnetic simulations coupled with a thermal solver was used to predict the microwave power absorption and the corresponding temperature evolution inside the samples. The additive with higher dielectric loss (4 wt% MgO, 6 wt% Y2O3 and 2.5 wt% ZrO2) produces a greater sintered density than the lower loss additive (4 wt% MgO and 6 wt% Y2O3) or pure Si3N4. Although microwave loss at temperatures below 600 degrees C is insignificant with or without the additives, the loss begins to increase at higher temperatures when the additives are present and has a strong upward trend above 1000 degrees C. Above 1200 degrees C the sample containing ZrO2 exhibited the greatest loss. Numerical simulations at the peak sintering temperature show greater microwave power absorption and higher temperature in the sample with the highest loss additive. The simulation results correlate to the difference in densification behavior observed. The simulation was also useful because the material temperature was not accurately provided by optical pyrometer measurements of the crucible sample holder.

  3. The effect of dielectric properties of sintering additives on microwave sintered silicon nitride ceramics.

    PubMed

    Chockalingam, Sreekumar; George, Jacob; Earl, David; Amarakoon, Vasantha R W

    2008-01-01

    Silicon nitride requires the use of susceptive additives for microwave liquid phase sintering due to the material's low dielectric loss. In this article, we report the effect of complex dielectric properties of two compositions of sintering aids on 2.45 GHz microwave sintered Si3N4 with respect to power absorption, temperature distribution and densification behavior. The temperature dependent dielectric properties were measured from 25 degrees C to 1400 degrees C using a conventional cavity perturbation technique. Finite Difference Time Domain (FDTD) electromagnetic simulations coupled with a thermal solver was used to predict the microwave power absorption and the corresponding temperature evolution inside the samples. The additive with higher dielectric loss (4 wt% MgO, 6 wt% Y2O3 and 2.5 wt% ZrO2) produces a greater sintered density than the lower loss additive (4 wt% MgO and 6 wt% Y2O3) or pure Si3N4. Although microwave loss at temperatures below 600 degrees C is insignificant with or without the additives, the loss begins to increase at higher temperatures when the additives are present and has a strong upward trend above 1000 degrees C. Above 1200 degrees C the sample containing ZrO2 exhibited the greatest loss. Numerical simulations at the peak sintering temperature show greater microwave power absorption and higher temperature in the sample with the highest loss additive. The simulation results correlate to the difference in densification behavior observed. The simulation was also useful because the material temperature was not accurately provided by optical pyrometer measurements of the crucible sample holder. PMID:19227072

  4. Preparation and characterization of ceramic products by thermal treatment of sewage sludge ashes mixed with different additives.

    PubMed

    Merino, Ignacio; Arévalo, Luis F; Romero, Fernando

    2007-01-01

    The study of the ceramic characteristics of sludge ashes, alone or mixed with additives (kaolin, montmorillonite, illitic clay, powdered flat glass) includes characterization of additives, preparation of probes (dry or wet mixed), thermal treatment (up to 1200 degrees C, except melting or deformation) and control (densities, compressive strengths and water absorption). Thermal treatment increases the density and compressive strength of probes (both parameters go through maxima, with later decreases) and decreases the absorption of water. The densification is also revealed by the evolution of the ratio of decrease of volume/loss of mass. The maximum values of compressive strengths were obtained for 25% of illitic clay, montmorillonite and glass powder. Densification concerning probes with sludge ashes alone does not occur with kaolin. Experimental data were adjusted to exponential relationships between compressive strengths and densities for every composition, and also to a general equation for all probes. The apparent density obtained was adjusted to a non-linear dependence with temperature, leading to a maximum in density and permitting calculating the temperature of occurrence of this maximum. The adjustment was not possible for probes containing kaolin, requiring presumably higher temperatures to densify. Water absorption has low values for ashes or kaolin probes, intermediate values for illite and powdered flat glass probes and high values for montmorillonite probes. Excepting with kaolin, ceramic materials with better characteristics than sludge ashes without additives were obtained at lower treatment temperatures. PMID:17150348

  5. Effects of Al/sub 2/O/sub 3/ additions on resistivity and microstructure of yttria-stabilized zirconia

    SciTech Connect

    Miyayama, M.; Yanagida, A.; Asada, A.

    1986-04-01

    Stabilized zirconia is a well-known oxygen ionic conductor which acts over a wide range of oxygen partial pressure. Hence the material has been developed for use in a variety of electrical applications such as oxygen sensors, oxygen pumps, and fuel cells. Since zirconia has a high melting point (approx. =2680/sup 0/C), temperatures in excess of 1600/sup 0/C are generally required for traditional fabrication techniques. Sintering agents and/or fine zirconia powders are required for producing dense, impermeable and mechanically strong stabilized zirconia ceramics. However, in most cases, sintering agents have a negative effect on the conduction behavior of stabilized zirconia. Small additions of SiO/sub 2/ are particularly effective for the densification of CaO-stabilized ZrO/sub 2/ (CSZ), but they cause a large increase in resistivity of Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/ (YSZ) at low temperatures. Additions of TiO/sub 2/ to CSZ, and of Fe/sub 2/O/sub 3/ and Bi/sub 2/O/sub 3/ to YSZ, are also reported to aid densification and cause moderate increases in resistivity. The effect of Al/sub 2/O/sub 3/ additions on the resistivity of stabilized zirconia is rather complicated.

  6. Characterization of pore evolution in ceramics during creep failure and densification. Final report, April 15, 1984--April 14, 1995

    SciTech Connect

    Page, R.A.; Chan, K.S.

    1995-04-01

    This research program was divided into two phases, one involving creep cavitation, the other cavity evolution during sintering. In the former, work was aimed at determining the effect of microstructure and stress state upon creep cavitation, while in the latter, the principal objective was the characterization of pore evolution during sintering. In order to meet these objectives, the creep cavitation portion of the program was centered around small-angle neutron scattering, supplemented by electron microscopy and precision density measurements. The neutron scattering measurements yielded cavity nucleation and growth rates, and average pore, size, distribution, and morphology. These data were used to evaluate current cavitation models, and to implement improved modelling efforts. Additionally, stereoimaging analysis was used to determine grain boundary sliding displacements, which appear to be the critical driving force responsible for cavity nucleation and early growth. Effort in the pore sintering phase focussed on characterization of pore evolution during intermediate and final stage sintering of alumina using both single and multiple scattering techniques. Electron microscopy, density measurements, and mercury intrusion porosimetry measurements complemented the scattering results. The effects of sintering trajectory, green state, powder morphology, and additives were evaluated. These results were compared to current sintering models.

  7. Granular encapsulation of light hydrophobic liquids (LHL) in LHL-salt water systems: Particle induced densification with quartz sand.

    PubMed

    Boglaienko, Daria; Tansel, Berrin; Sukop, Michael C

    2016-02-01

    Addition of granular materials to floating crude oil slicks can be effective in capturing and densifying the floating hydrophobic phase, which settles by gravity. Interaction of light hydrophobic liquids (LHL) with quartz sand was investigated in LHL-salt water systems. The LHLs studied were decane, tetradecane, hexadecane, benzene, toluene, ethylbenzene, m-xylene, and 2-cholorotoluene. Experiments were conducted with fine quartz sand (passing sieve No. 40 with openings 0.425 mm). Each LHL was dyed with few crystals of Sudan IV dye for ease of visual observation. A volume of 0.5 mL of each LHL was added to 100 mL salt water (34 g/L). Addition of one gram of quartz sand to the floating hydrophobic liquid layer resulted in formation of sand-encapsulated globules, which settled due to increased density. All LHLs (except for a few globules of decane) formed globules covered with fine sand particles that were heavy enough to settle by gravity. The encapsulated globules were stable and retained their shape upon settling. Polarity of hydrophobic liquids as the main factor of aggregation with minerals was found to be insufficient to explain LHL aggregation with sand. Contact angle measurements were made by submerging a large quartz crystal with the LHL drop on its surface into salt water. A positive correlation was observed between the wetting angle of LHL and the LHL volume captured (r = 0.75). The dependence of the globule density on globule radius was analyzed in relation to the coverage (%) of globule surface (LHL-salt water interface) by fine quartz particles. PMID:26490430

  8. Granular encapsulation of light hydrophobic liquids (LHL) in LHL-salt water systems: Particle induced densification with quartz sand.

    PubMed

    Boglaienko, Daria; Tansel, Berrin; Sukop, Michael C

    2016-02-01

    Addition of granular materials to floating crude oil slicks can be effective in capturing and densifying the floating hydrophobic phase, which settles by gravity. Interaction of light hydrophobic liquids (LHL) with quartz sand was investigated in LHL-salt water systems. The LHLs studied were decane, tetradecane, hexadecane, benzene, toluene, ethylbenzene, m-xylene, and 2-cholorotoluene. Experiments were conducted with fine quartz sand (passing sieve No. 40 with openings 0.425 mm). Each LHL was dyed with few crystals of Sudan IV dye for ease of visual observation. A volume of 0.5 mL of each LHL was added to 100 mL salt water (34 g/L). Addition of one gram of quartz sand to the floating hydrophobic liquid layer resulted in formation of sand-encapsulated globules, which settled due to increased density. All LHLs (except for a few globules of decane) formed globules covered with fine sand particles that were heavy enough to settle by gravity. The encapsulated globules were stable and retained their shape upon settling. Polarity of hydrophobic liquids as the main factor of aggregation with minerals was found to be insufficient to explain LHL aggregation with sand. Contact angle measurements were made by submerging a large quartz crystal with the LHL drop on its surface into salt water. A positive correlation was observed between the wetting angle of LHL and the LHL volume captured (r = 0.75). The dependence of the globule density on globule radius was analyzed in relation to the coverage (%) of globule surface (LHL-salt water interface) by fine quartz particles.

  9. Effects of Rare Earth (RE) Intergranular Adsorption on the Phase Transformation and Microstructure Evolution in Silicon Nitride with RE2O3 + MgO Additives: Fracture Behavior

    SciTech Connect

    Becher, Paul F; Painter, Gayle S; Shibata, Naoya; Waters, Shirley B; Lin, Hua-Tay

    2008-07-01

    Silicon nitride powders consist primarily of the alpha phase, which transforms to the beta phase during the densification and microstructural evolution of Si3N4 ceramics. The temperature at which the transformation initiates in the presence of a combination of MgO and RE2O3 densification additives is found to decrease with increasing atomic number of the rare earth (RE). This trend coincides with the predicted and observed decrease in the affinity of the rare earth to segregate to and absorb on the prism planes of hexagonal prism shaped beta grains with increase in the atomic number of the RE. When RE adsorption is diminished, Si (and N) attachment on the smooth prism planes is enhanced, which increases diametrical growth rates, normally reaction-rate limited by an attachment mechanism. Combined with the typically fast [0001] growth, it is this augmented grain growth that contributes towards the initiation of the alpha-beta transformation at lower temperatures. With the enhanced transformation, observations reveal an increase in the number of beta grains growing in the early stages of densification. On the other hand, increased RE adsorption leads to greater growth anisotropy resulting in the formation of higher aspect ratio grains. Thus, Lu2O3 generates larger diameter, yet elongated, reinforcing grains, while La2O3 results in reinforcing grains of higher aspect ratio. The Gd2O3 additive transformation and microstructual characteristics lie intermediate to those of the lanthanide end member elements. Despite these differences, a substantial fraction of large reinforcing grains were found for each additive composition. As a result, the mechanical properties of the resultant ceramics are similar with flexure strengths in excess of 1 GPa, fracture toughness values greater than 10 MPa m1/2 at room temperature and excellent strength retention (>800 MPa) at 1200 C.

  10. Layered growth of crayfish gastrolith: about the stability of amorphous calcium carbonate and role of additives.

    PubMed

    Habraken, Wouter J E M; Masic, Admir; Bertinetti, Luca; Al-Sawalmih, Ali; Glazer, Lilah; Bentov, Shmuel; Fratzl, Peter; Sagi, Amir; Aichmayer, Barbara; Berman, Amir

    2015-01-01

    Previous studies on pre-molt gastroliths have shown a typical onion-like morphology of layers of amorphous mineral (mostly calcium carbonate) and chitin, resulting from the continuous deposition and densification of amorphous mineral spheres on a chitin-matrix during time. To investigate the consequences of this layered growth on the local structure and composition of the gastrolith, we performed spatially-resolved Raman, X-ray and SEM-EDS analysis on complete pre-molt gastrolith cross-sections. Results show that especially the abundance of inorganic phosphate, phosphoenolpyruvate (PEP)/citrate and proteins is not uniform throughout the organ but changes from layer to layer. Based on these results we can conclude that ACC stabilization in the gastrolith takes place by more than one compound and not by only one of these additives.

  11. [Food additives and healthiness].

    PubMed

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  12. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Fletcher, James C. (Inventor); Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1992-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  13. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1993-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of the additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  14. Additional Types of Neuropathy

    MedlinePlus

    ... A A Listen En Español Additional Types of Neuropathy Charcot's Joint Charcot's Joint, also called neuropathic arthropathy, ... can stop bone destruction and aid healing. Cranial Neuropathy Cranial neuropathy affects the 12 pairs of nerves ...

  15. Food Additives and Hyperkinesis

    ERIC Educational Resources Information Center

    Wender, Ester H.

    1977-01-01

    The hypothesis that food additives are causally associated with hyperkinesis and learning disabilities in children is reviewed, and available data are summarized. Available from: American Medical Association 535 North Dearborn Street Chicago, Illinois 60610. (JG)

  16. Smog control fuel additives

    SciTech Connect

    Lundby, W.

    1993-06-29

    A method is described of controlling, reducing or eliminating, ozone and related smog resulting from photochemical reactions between ozone and automotive or industrial gases comprising the addition of iodine or compounds of iodine to hydrocarbon-base fuels prior to or during combustion in an amount of about 1 part iodine per 240 to 10,000,000 parts fuel, by weight, to be accomplished by: (a) the addition of these inhibitors during or after the refining or manufacturing process of liquid fuels; (b) the production of these inhibitors for addition into fuel tanks, such as automotive or industrial tanks; or (c) the addition of these inhibitors into combustion chambers of equipment utilizing solid fuels for the purpose of reducing ozone.

  17. LTCC processed CoTi substituted M-type barium ferrite composite with BBSZ glass powder additives for microwave device applications

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Liu, Yingli; Li, Jie; Liu, Qian; Zhang, Huaiwu; Harris, Vincent. G.

    2016-05-01

    Hexagonal magnetoplumbite ferrites typically have sintering temperatures above 1100∘C in order to stabilize a single phase compound, which is much higher than the melting point of silver leading to device fabrication challenges. Application of low temperature co-fired ceramics (LTCC) technologies may prove effective in decreasing the sintering temperature of hexagonal ferrites. Ferrite powders combined with glass frit powder is an effective pathway to lowering the sintering temperature. Here, hexagonal M-type barium ferrite (i.e., Ba(CoTi)1.5Fe9O19) ceramics, combined with BBSZ glass powder as a sintering aid were synthesized. Co and Ti ions where used to substitute for Fe cations in order to modify the magnetic anisotropy field. The density, microstructure, magnetic properties and complex permeability are reported. The BBSZ glass addition was shown to improve the densification and magnetic properties of the barium ferrite. The densification of the BaM ferrite Ba(CoTi)1.5Fe9O19 was further enhanced by the glass additive at low firing temperatures of below 900∘C because of the formation of a liquid phase. Complex permeability of ferrites sintered at 900∘C was also influenced by the BBSZ addition and the resonance frequency was shown to decrease with increased amounts of the glass modifier.

  18. Additive Manufacturing Infrared Inspection

    NASA Technical Reports Server (NTRS)

    Gaddy, Darrell

    2014-01-01

    Additive manufacturing is a rapid prototyping technology that allows parts to be built in a series of thin layers from plastic, ceramics, and metallics. Metallic additive manufacturing is an emerging form of rapid prototyping that allows complex structures to be built using various metallic powders. Significant time and cost savings have also been observed using the metallic additive manufacturing compared with traditional techniques. Development of the metallic additive manufacturing technology has advanced significantly over the last decade, although many of the techniques to inspect parts made from these processes have not advanced significantly or have limitations. Several external geometry inspection techniques exist such as Coordinate Measurement Machines (CMM), Laser Scanners, Structured Light Scanning Systems, or even traditional calipers and gages. All of the aforementioned techniques are limited to external geometry and contours or must use a contact probe to inspect limited internal dimensions. This presentation will document the development of a process for real-time dimensional inspection technique and digital quality record of the additive manufacturing process using Infrared camera imaging and processing techniques.

  19. Gas-Solid Interactions During Nonisothermal Heat Treatment of a High-Strength CrMnCN Austenitic Steel Powder: Influence of Atmospheric Conditions and Heating Rate on the Densification Behavior

    NASA Astrophysics Data System (ADS)

    Krasokha, Nikolaj; Weber, Sebastian; Huth, Stephan; Zumsande, Kathrin; Theisen, Werner

    2012-11-01

    This work deals with gas-solid interactions between a high-alloyed steel powder and the surrounding atmosphere during continuous heating. It is motivated by the recently developed corrosion-resistant CrMnCN austenitic cast steels. Here, powder metallurgical processing would be desirable to manufacture highly homogeneous parts and/or novel corrosion-resistant metal-matrix composites. However, the successful use of this new production route calls for a comprehensive investigation of interactions between the sintering atmosphere and the metallic powder to prevent undesirable changes to the chemical composition, e.g., degassing of nitrogen or evaporation of manganese. In this study, dilatometric measurements combined with residual gas analysis, high-temperature X-ray diffraction (XRD) measurements, and thermodynamic equilibrium calculations provided detailed information about the influence of different atmospheric conditions on the microstructure, constitution, and densification behavior of a gas-atomized CrMnCN steel powder during continuous heating. Intensive desorption of nitrogen led to the conclusion that a vacuum atmosphere is not suitable for powder metallurgical (PM) processing. Exposure to an N2-containing atmosphere resulted in the formation of nitrides and lattice expansion. Experimental findings have shown that the N content can be controlled by the nitrogen partial pressure. Furthermore, the reduction of surface oxides because of a carbothermal reaction at elevated temperatures and the resulting enhancement of the powder's densification behavior are discussed in this work.

  20. Influences of Gd2Ti2O7 sintering aid on the densification, ionic conductivity and thermal expansion of Gd0.1Ce0.9O1.95 electrolyte for solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Guo, Ting; Zhang, Lei; Song, Xiao; Dong, Xiaolei; Shirolkar, Mandar M.; Wang, Meng; Li, Ming; Wang, Haiqian

    2014-09-01

    The effects of Gd2Ti2O7 (GT) as sintering aid on the densification, electrical properties and thermal expansion of Gd0.1Ce0.9O1.95 (GDC) are examined. Samples added with TiO2 sintering aid are also tested for comparison. It is found that by sintering at a moderate temperature of 1400 °C for 5 h, the relative density of the GT-added GDC can reach over 97% as the molar ratio of GT/GDC reaches 0.02 or higher. XRD analysis indicates that GT does not react with GDC, while TiO2 reacts with Gd in GDC to form GT. The ionic conductivities of the GT-added and the TiO2-added GDC are analyzed by AC impedance spectroscopy at 500-700 °C. The result shows that although the ionic conductivity of the GT-added GDC decreases as the GT/GDC molar ratio increases up to 0.05, it is still higher than that of 8YSZ and much higher than that of the GDC added with an equivalent amount of TiO2. It is also found that the thermal expansion coefficient of GDC decreases as the amount of GT increases. These results show that GT is an excellent sintering aid for GDC, and the optimal molar ratio of GT/GDC is 0.02 in terms of densification and ionic conductivity.

  1. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  2. Multifunctional fuel additives

    SciTech Connect

    Baillargeon, D.J.; Cardis, A.B.; Heck, D.B.

    1991-03-26

    This paper discusses a composition comprising a major amount of a liquid hydrocarbyl fuel and a minor low-temperature flow properties improving amount of an additive product of the reaction of a suitable diol and product of a benzophenone tetracarboxylic dianhydride and a long-chain hydrocarbyl aminoalcohol.

  3. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  4. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1991-01-01

    Polyimide resins (PMR) are generally useful where high strength and temperature capabilities are required (at temperatures up to about 700 F). Polyimide resins are particularly useful in applications such as jet engine compressor components, for example, blades, vanes, air seals, air splitters, and engine casing parts. Aromatic vinyl capped addition polyimides are obtained by reacting a diamine, an ester of tetracarboxylic acid, and an aromatic vinyl compound. Low void materials with improved oxidative stability when exposed to 700 F air may be fabricated as fiber reinforced high molecular weight capped polyimide composites. The aromatic vinyl capped polyimides are provided with a more aromatic nature and are more thermally stable than highly aliphatic, norbornenyl-type end-capped polyimides employed in PMR resins. The substitution of aromatic vinyl end-caps for norbornenyl end-caps in addition polyimides results in polymers with improved oxidative stability.

  5. Tackifier for addition polyimides

    NASA Technical Reports Server (NTRS)

    Butler, J. M.; St.clair, T. L.

    1980-01-01

    A modification to the addition polyimide, LaRC-160, was prepared to improve tack and drape and increase prepeg out-time. The essentially solventless, high viscosity laminating resin is synthesized from low cost liquid monomers. The modified version takes advantage of a reactive, liquid plasticizer which is used in place of solvent and helps solve a major problem of maintaining good prepeg tack and drape, or the ability of the prepeg to adhere to adjacent plies and conform to a desired shape during the lay up process. This alternate solventless approach allows both longer life of the polymer prepeg and the processing of low void laminates. This approach appears to be applicable to all addition polyimide systems.

  6. Electrophilic addition of astatine

    SciTech Connect

    Norseev, Yu.V.; Vasaros, L.; Nhan, D.D.; Huan, N.K.

    1988-03-01

    It has been shown for the first time that astatine is capable of undergoing addition reactions to unsaturated hydrocarbons. A new compound of astatine, viz., ethylene astatohydrin, has been obtained, and its retention numbers of squalane, Apiezon, and tricresyl phosphate have been found. The influence of various factors on the formation of ethylene astatohydrin has been studied. It has been concluded on the basis of the results obtained that the univalent cations of astatine in an acidic medium is protonated hypoastatous acid.

  7. Functional Generalized Additive Models.

    PubMed

    McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

    2014-01-01

    We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online.

  8. Influence of nanogold additives on phase formation, microstructure and dielectric properties of perovskite BaTiO3 ceramics

    NASA Astrophysics Data System (ADS)

    Nonkumwong, Jeeranan; Ananta, Supon; Srisombat, Laongnuan

    2015-06-01

    The formation of perovskite phase, microstructure and dielectric properties of nanogold-modified barium titanate (BaTiO3) ceramics was examined as a function of gold nanoparticle contents by employing a combination of X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, Archimedes principle and dielectric measurement techniques. These ceramics were fabricated from a simple mixed-oxide method. The amount of gold nanoparticles was found to be one of the key factors controlling densification, grain growth and dielectric response in BaTiO3 ceramics. It was found that under suitable amount of nanogold addition (4 mol%), highly dense perovskite BaTiO3 ceramics with homogeneous microstructures of refined grains (~0.5-3.1 μm) and excellence dielectric properties can be produced.

  9. Performance Boosting Additive

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mainstream Engineering Corporation was awarded Phase I and Phase II contracts from Goddard Space Flight Center's Small Business Innovation Research (SBIR) program in early 1990. With support from the SBIR program, Mainstream Engineering Corporation has developed a unique low cost additive, QwikBoost (TM), that increases the performance of air conditioners, heat pumps, refrigerators, and freezers. Because of the energy and environmental benefits of QwikBoost, Mainstream received the Tibbetts Award at a White House Ceremony on October 16, 1997. QwikBoost was introduced at the 1998 International Air Conditioning, Heating, and Refrigeration Exposition. QwikBoost is packaged in a handy 3-ounce can (pressurized with R-134a) and will be available for automotive air conditioning systems in summer 1998.

  10. Sewage sludge additive

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

    1980-01-01

    The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

  11. Perspectives on Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Bourell, David L.

    2016-07-01

    Additive manufacturing (AM) has skyrocketed in visibility commercially and in the public sector. This article describes the development of this field from early layered manufacturing approaches of photosculpture, topography, and material deposition. Certain precursors to modern AM processes are also briefly described. The growth of the field over the last 30 years is presented. Included is the standard delineation of AM technologies into seven broad categories. The economics of AM part generation is considered, and the impacts of the economics on application sectors are described. On the basis of current trends, the future outlook will include a convergence of AM fabricators, mass-produced AM fabricators, enabling of topology optimization designs, and specialization in the AM legal arena. Long-term developments with huge impact are organ printing and volume-based printing.

  12. Sarks as additional fermions

    NASA Astrophysics Data System (ADS)

    Agrawal, Jyoti; Frampton, Paul H.; Jack Ng, Y.; Nishino, Hitoshi; Yasuda, Osamu

    1991-03-01

    An extension of the standard model is proposed. The gauge group is SU(2) X ⊗ SU(3) C ⊗ SU(2) S ⊗ U(1) Q, where all gauge symmetries are unbroken. The colour and electric charge are combined with SU(2) S which becomes strongly coupled at approximately 500 GeV and binds preons to form fermionic and vector bound states. The usual quarks and leptons are singlets under SU(2) X but additional fermions, called sarks. transform under it and the electroweak group. The present model explains why no more than three light quark-lepton families can exist. Neutral sark baryons, called narks, are candidates for the cosmological dark matter having the characteristics designed for WIMPS. Further phenomenological implications of sarks are analyzed i including electron-positron annihilation. Z 0 decay, flavor-changing neutral currents. baryon-number non-conservation, sarkonium and the neutron electric dipole moment.

  13. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes. PMID:27679822

  14. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  15. Matlab based automatization of an inverse surface temperature modelling procedure for Greenland ice cores using an existing firn densification and heat diffusion model

    NASA Astrophysics Data System (ADS)

    Döring, Michael; Kobashi, Takuro; Kindler, Philippe; Guillevic, Myriam; Leuenberger, Markus

    2016-04-01

    In order to study Northern Hemisphere (NH) climate interactions and variability, getting access to high resolution surface temperature records of the Greenland ice sheet is an integral condition. For example, understanding the causes for changes in the strength of the Atlantic meridional overturning circulation (AMOC) and related effects for the NH [Broecker et al. (1985); Rahmstorf (2002)] or the origin and processes leading the so called Dansgaard-Oeschger events in glacial conditions [Johnsen et al. (1992); Dansgaard et al., 1982] demand accurate and reproducible temperature data. To reveal the surface temperature history, it is suitable to use the isotopic composition of nitrogen (δ15N) from ancient air extracted from ice cores drilled at the Greenland ice sheet. The measured δ15N record of an ice core can be used as a paleothermometer due to the nearly constant isotopic composition of nitrogen in the atmosphere at orbital timescales changes only through firn processes [Severinghaus et. al. (1998); Mariotti (1983)]. To reconstruct the surface temperature for a special drilling site the use of firn models describing gas and temperature diffusion throughout the ice sheet is necessary. For this an existing firn densification and heat diffusion model [Schwander et. al. (1997)] is used. Thereby, a theoretical δ15N record is generated for different temperature and accumulation rate scenarios and compared with measurement data in terms of mean square error (MSE), which leads finally to an optimization problem, namely the finding of a minimal MSE. The goal of the presented study is a Matlab based automatization of this inverse modelling procedure. The crucial point hereby is to find the temperature and accumulation rate input time series which minimizes the MSE. For that, we follow two approaches. The first one is a Monte Carlo type input generator which varies each point in the input time series and calculates the MSE. Then the solutions that fulfil a given limit

  16. Matlab based automatization of an inverse surface temperature modelling procedure for Greenland ice cores using an existing firn densification and heat diffusion model

    NASA Astrophysics Data System (ADS)

    Döring, Michael; Kobashi, Takuro; Kindler, Philippe; Guillevic, Myriam; Leuenberger, Markus

    2016-04-01

    In order to study Northern Hemisphere (NH) climate interactions and variability, getting access to high resolution surface temperature records of the Greenland ice sheet is an integral condition. For example, understanding the causes for changes in the strength of the Atlantic meridional overturning circulation (AMOC) and related effects for the NH [Broecker et al. (1985); Rahmstorf (2002)] or the origin and processes leading the so called Dansgaard-Oeschger events in glacial conditions [Johnsen et al. (1992); Dansgaard et al., 1982] demand accurate and reproducible temperature data. To reveal the surface temperature history, it is suitable to use the isotopic composition of nitrogen (δ15N) from ancient air extracted from ice cores drilled at the Greenland ice sheet. The measured δ15N record of an ice core can be used as a paleothermometer due to the nearly constant isotopic composition of nitrogen in the atmosphere at orbital timescales changes only through firn processes [Severinghaus et. al. (1998); Mariotti (1983)]. To reconstruct the surface temperature for a special drilling site the use of firn models describing gas and temperature diffusion throughout the ice sheet is necessary. For this an existing firn densification and heat diffusion model [Schwander et. al. (1997)] is used. Thereby, a theoretical δ15N record is generated for different temperature and accumulation rate scenarios and compared with measurement data in terms of mean square error (MSE), which leads finally to an optimization problem, namely the finding of a minimal MSE. The goal of the presented study is a Matlab based automatization of this inverse modelling procedure. The crucial point hereby is to find the temperature and accumulation rate input time series which minimizes the MSE. For that, we follow two approaches. The first one is a Monte Carlo type input generator which varies each point in the input time series and calculates the MSE. Then the solutions that fulfil a given limit

  17. Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

    NASA Technical Reports Server (NTRS)

    Ueno, K.; Toibana, Y.

    1984-01-01

    The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

  18. A role of BNLT compound addition on structure and properties of PZT ceramics

    NASA Astrophysics Data System (ADS)

    Jaita, P.; Watcharapasorn, A.; Jiansirisomboon, S.

    2010-09-01

    In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1-3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050-1200 °C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and KIC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.

  19. Influence of CuO addition to BaSm{sub 2}Ti{sub 4}O{sub 12} microwave ceramics on sintering behavior and dielectric properties

    SciTech Connect

    Zuo Mingwen; Li Wei . E-mail: liwei@mail.sic.ac.cn; Shi Jianlin; Zeng Qun

    2006-06-15

    Microwave dielectric ceramics of tungsten-bronze-type BaSm{sub 2}Ti{sub 4}O{sub 12} were prepared by doping CuO (up to 2 wt.%) as the liquid-phase sintering aid. The effects of CuO additive on the densification, micro structure and dielectric properties were investigated. Due to the liquid-phase effect, the sintering temperature of BaSm{sub 2}Ti{sub 4}O{sub 12} ceramics with 1 wt.% CuO addition can be effectively reduced to 1160 deg. C, about 200 deg. C lower than that of pure BaSm{sub 2}Ti{sub 4}O{sub 12} ceramics, while good microwave dielectric properties of {epsilon} {sub r} = 75.8, Q*f = 4914.6 GHz and {tau} {sub f} = -7.65 ppm/deg. C were still achieved.

  20. Effects of gallia addition on sintering behavior and electrical conductivity of yttria-doped ceria

    NASA Astrophysics Data System (ADS)

    Seo, Seung-Woo; Park, Ji-Hoon; Park, Min-Woo; Koo, Ji-Hoon; Lee, Ki-Tae; Lee, Joo-Sin

    2014-07-01

    The densification behavior and electrical conductivity of Ce0.8Y0.2O1.9 ceramics with gallia concentrations ranging from 0 to 5 mol. % were investigated. The sintered density was found to increase with increasing Ga2O3 content up to 1 mol. % and then to decrease upon further Ga2O3 addition. Dense Ce0.8Y0.2O1.9 ceramics with 94% of the theoretical density could be obtained by sintering the milled mixture with 1 mol. % Ga2O3 addition at 1400°C for 5 h. The conductivity of the 1 mol. % Ga2O3-added specimen showed a maximum value of 1.37 × 10-2 Ω-1· cm-1 at 700°C. Pure Ce0.8Y0.2O1.9 ceramics needed to be sintered at 1550°C in order to obtain an equivalent theoretical density and conductivity. The introduction of Ga2O3 doping had a good effect on the sintering properties and electrical conductivities of Y2O3-doped CeO2.

  1. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  2. [Patch-testing methods: additional specialised or additional series].

    PubMed

    Cleenewerck, M-B

    2009-01-01

    The tests in the European standard battery must occasionally be supplemented by specialised or additional batteries, particularly where the contact allergy is thought to be of occupational origin. These additional batteries cover all allergens associated with various professional activities (hairdressing, baking, dentistry, printing, etc.) and with different classes of materials and chemical products (glue, plastic, rubber...). These additional tests may also include personal items used by patients on a daily basis such as cosmetics, shoes, plants, textiles and so on.

  3. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  4. Enantioselective Michael Addition of Water

    PubMed Central

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry. PMID:25529526

  5. Enantioselective Michael addition of water.

    PubMed

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-02-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry.

  6. Gasoline additives, emissions, and performance

    SciTech Connect

    1995-12-31

    The papers included in this publication deal with the influence of fuel, additive, and hardware changes on a variety of vehicle performance characteristics. Advanced techniques for measuring these performance parameters are also described. Contents include: Fleet test evaluation of gasoline additives for intake valve and combustion chamber deposit clean up; A technique for evaluating octane requirement additives in modern engines on dynamometer test stands; A fleet test of two additive technologies comparing their effects on tailpipe emissions; Investigation into the vehicle exhaust emissions of high percentage ethanol blends; Variability in hydrocarbon speciation measurements at low emission (ULEV) levels; and more.

  7. Color Addition and Subtraction Apps

    ERIC Educational Resources Information Center

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  8. Color Addition and Subtraction Apps

    NASA Astrophysics Data System (ADS)

    Ruiz, Frances; Ruiz, Michael J.

    2015-10-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.

  9. Teebi hypertelorism syndrome: additional cases.

    PubMed

    Machado-Paula, Ligiane Alves; Guion-Almeida, Maria Leine

    2003-03-01

    We report on two unrelated Brazilian boys who have craniofacial and digital anomalies resembling those reported with Teebi hypertelorism syndrome. Additional features such as cleft lip and palate, large uvula, atypical chin and abnormal scapulae were observed.

  10. Polyolefins as additives in plastics

    SciTech Connect

    Deanin, R.D.

    1993-12-31

    Polyolefins are not only major commodity plastics - they are also very useful as additives, both in other polyolefins and also in other types of plastics. This review covers ethylene, propylene, butylene and isobutylene polymers, in blends with each other, and as additives to natural rubber, styrene/butadiene rubber, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyphenylene oxide, polycarbonate, thermoplastic polyesters, polyurethanes, polyamides, and mixed automotive plastics recycling.

  11. Food additives and preschool children.

    PubMed

    Martyn, Danika M; McNulty, Breige A; Nugent, Anne P; Gibney, Michael J

    2013-02-01

    Food additives have been used throughout history to perform specific functions in foods. A comprehensive framework of legislation is in place within Europe to control the use of additives in the food supply and ensure they pose no risk to human health. Further to this, exposure assessments are regularly carried out to monitor population intakes and verify that intakes are not above acceptable levels (acceptable daily intakes). Young children may have a higher dietary exposure to chemicals than adults due to a combination of rapid growth rates and distinct food intake patterns. For this reason, exposure assessments are particularly important in this age group. The paper will review the use of additives and exposure assessment methods and examine factors that affect dietary exposure by young children. One of the most widely investigated unfavourable health effects associated with food additive intake in preschool-aged children are suggested adverse behavioural effects. Research that has examined this relationship has reported a variety of responses, with many noting an increase in hyperactivity as reported by parents but not when assessed using objective examiners. This review has examined the experimental approaches used in such studies and suggests that efforts are needed to standardise objective methods of measuring behaviour in preschool children. Further to this, a more holistic approach to examining food additive intakes by preschool children is advisable, where overall exposure is considered rather than focusing solely on behavioural effects and possibly examining intakes of food additives other than food colours.

  12. Extension of the standard addition method by blank addition.

    PubMed

    Steliopoulos, Panagiotis

    2015-01-01

    Standard addition involves adding varying amounts of the analyte to sample portions of fixed mass or fixed volume and submitting those portions to the sample preparation procedure. After measuring the final extract solutions, the observed signals are linearly regressed on the spiked amounts. The original unknown amount is estimated by the opposite of the abscissa intercept of the fitted straight line [1]. A limitation of this method is that only data points with abscissa values equal to and greater than zero are available so that there is no information on whether linearity holds below the spiking level zero. An approach to overcome this limitation is introduced.•Standard addition is combined with blank addition.•Blank addition means that defined mixtures of blank matrix and sample material are subjected to sample preparation to give final extract solutions.•Equations are presented to estimate the original unknown amount and to calculate the 1-2α confidence interval about this estimate using the combined data set.

  13. ADDITIVITY ASSESSMENT OF TRIHALOMETHANE MIXTURES BY PROPORTIONAL RESPONSE ADDITION

    EPA Science Inventory

    If additivity is known or assumed, the toxicity of a chemical mixture may be predicted from the dose response curves of the individual chemicals comprising the mixture. As single chemical data are abundant and mixture data sparse, mixture risk methods that utilize single chemical...

  14. Extension of the standard addition method by blank addition

    PubMed Central

    Steliopoulos, Panagiotis

    2015-01-01

    Standard addition involves adding varying amounts of the analyte to sample portions of fixed mass or fixed volume and submitting those portions to the sample preparation procedure. After measuring the final extract solutions, the observed signals are linearly regressed on the spiked amounts. The original unknown amount is estimated by the opposite of the abscissa intercept of the fitted straight line [1]. A limitation of this method is that only data points with abscissa values equal to and greater than zero are available so that there is no information on whether linearity holds below the spiking level zero. An approach to overcome this limitation is introduced.•Standard addition is combined with blank addition.•Blank addition means that defined mixtures of blank matrix and sample material are subjected to sample preparation to give final extract solutions.•Equations are presented to estimate the original unknown amount and to calculate the 1-2α confidence interval about this estimate using the combined data set. PMID:26844210

  15. CaO--P2O5--Na2O-based sintering additives for hydroxyapatite (HAp) ceramics.

    PubMed

    Kalita, S J; Bose, S; Hosick, H L; Bandyopadhyay, A

    2004-05-01

    We have assessed the effect of CaO--P2O5--Na2O-based sintering additives on mechanical and biological properties of hydroxyapatite (HAp) ceramics. Five different compositions of sintering additives were selected and prepared by mixing of CaO, P2O5, and Na2CO3 powders. 2.5 wt% of each additive was combined with commercial HAp powder, separately, followed by ball milling, and sintering at 1250 degrees C and 1300 degrees C in a muffle furnace. Green and sintered densities of the compacts were analyzed for the influence of additives on densification of HAp. Phase analyses were carried out using an X-ray diffractometer. Vickers microhardness testing was used to evaluate hardness of sintered compacts of different compositions. A maximum microhardness of 4.6 (+/- 0.28) GPa was attained for a composition with 2.5 wt% addition of CaO:P2O5:Na2O in the ratio of 3:3:4. Results from mechanical property evaluation showed that some of these sintering additives improved failure strength of HAp under compressive loading. Maximum compressive strength was observed for samples with 2.5 wt% addition of CaO. Average failure strength for this set of samples was calculated to be 220 (+/- 50) MPa. Cytotoxicity, and cell attachment studies were carried out using a modified human osteoblast cell line called OPC-1. In vitro results showed that these compositions were non-toxic. Some sintering aids enhanced cell attachment and proliferation, which was revealed from SEM examination of the scaffolds seeded with OPC-1 cells. PMID:14741598

  16. [INVITED] Lasers in additive manufacturing

    NASA Astrophysics Data System (ADS)

    Pinkerton, Andrew J.

    2016-04-01

    Additive manufacturing is a topic of considerable ongoing interest, with forecasts predicting it to have major impact on industry in the future. This paper focusses on the current status and potential future development of the technology, with particular reference to the role of lasers within it. It begins by making clear the types and roles of lasers in the different categories of additive manufacturing. This is followed by concise reviews of the economic benefits and disadvantages of the technology, current state of the market and use of additive manufacturing in different industries. Details of these fields are referenced rather than expanded in detail. The paper continues, focusing on current indicators to the future of additive manufacturing. Barriers to its development, trends and opportunities in major industrial sectors, and wider opportunities for its development are covered. Evidence indicates that additive manufacturing may not become the dominant manufacturing technology in all industries, but represents an excellent opportunity for lasers to increase their influence in manufacturing as a whole.

  17. Evaluation of certain food additives.

    PubMed

    2015-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, and to prepare specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for eight food additives (Benzoe tonkinensis; carrageenan; citric and fatty acid esters of glycerol; gardenia yellow; lutein esters from Tagetes erecta; octenyl succinic acid-modified gum arabic; octenyl succinic acid-modified starch; paprika extract; and pectin) and eight groups of flavouring agents (aliphatic and alicyclic hydrocarbons; aliphatic and aromatic ethers; ionones and structurally related substances; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; phenol and phenol derivatives; phenyl-substituted aliphatic alcohols and related aldehydes and esters; and sulfur-containing heterocyclic compounds). Specifications for the following food additives were revised: citric acid; gellan gum; polyoxyethylene (20) sorbitan monostearate; potassium aluminium silicate; and Quillaia extract (Type 2). Annexed to the report are tables summarizing the Committee's recommendations for dietary exposures to and toxicological evaluations of all of the food additives and flavouring agents considered at this meeting.

  18. Clinical effects of sulphite additives.

    PubMed

    Vally, H; Misso, N L A; Madan, V

    2009-11-01

    Sulphites are widely used as preservative and antioxidant additives in the food and pharmaceutical industries. Topical, oral or parenteral exposure to sulphites has been reported to induce a range of adverse clinical effects in sensitive individuals, ranging from dermatitis, urticaria, flushing, hypotension, abdominal pain and diarrhoea to life-threatening anaphylactic and asthmatic reactions. Exposure to the sulphites arises mainly from the consumption of foods and drinks that contain these additives; however, exposure may also occur through the use of pharmaceutical products, as well as in occupational settings. While contact sensitivity to sulphite additives in topical medications is increasingly being recognized, skin reactions also occur after ingestion of or parenteral exposure to sulphites. Most studies report a 3-10% prevalence of sulphite sensitivity among asthmatic subjects following ingestion of these additives. However, the severity of these reactions varies, and steroid-dependent asthmatics, those with marked airway hyperresponsiveness, and children with chronic asthma, appear to be at greater risk. In addition to episodic and acute symptoms, sulphites may also contribute to chronic skin and respiratory symptoms. To date, the mechanisms underlying sulphite sensitivity remain unclear, although a number of potential mechanisms have been proposed. Physicians should be aware of the range of clinical manifestations of sulphite sensitivity, as well as the potential sources of exposure. Minor modifications to diet or behaviour lead to excellent clinical outcomes for sulphite-sensitive individuals.

  19. Additive Manufacturing of Hybrid Circuits

    NASA Astrophysics Data System (ADS)

    Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David; Hirschfeld, Deidre; Hall, Aaron C.; Bell, Nelson S.

    2016-07-01

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects. Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. Finally, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.

  20. Postmarketing surveillance of food additives.

    PubMed

    Butchko, H H; Tschanz, C; Kotsonis, F N

    1994-08-01

    Postmarketing surveillance of consumption and of anecdotal reports of adverse health effects has been recognized by a number of regulatory authorities as a potentially useful method to provide further assurance of the safety of new food additives. Surveillance of consumption is used to estimate more reliably actual consumption levels relative to the acceptable daily intake of a food additive. Surveillance of anecdotal reports of adverse health effects is used to determine the presence of infrequent idiosyncratic responses that may not be predictable from premarket evaluations. The high-intensity sweetner, aspartame, is a food additive that has been the subject of extensive evaluation during the postmarketing period and is thus used as an example to discuss postmarketing surveillance.

  1. Tougher Addition Polyimides Containing Siloxane

    NASA Technical Reports Server (NTRS)

    St. Clair, T. L.; Maudgal, S.

    1986-01-01

    Laminates show increased impact resistances and other desirable mechanical properties. Bismaleamic acid extended by reaction of diaminosiloxane with maleic anhydride in 1:1 molar ratio, followed by reaction with half this molar ratio of aromatic dianhydride. Bismaleamic acid also extended by reaction of diaminosiloxane with maleic anhydride in 1:2 molar ratio, followed by reaction with half this molar ratio of aromatic diamine (Michael-addition reaction). Impact resistances improved over those of unmodified bismaleimide, showing significant increase in toughness. Aromatic addition polyimides developed as both matrix and adhesive resins for applications on future aircraft and spacecraft.

  2. Lubricating additive for drilling muds

    SciTech Connect

    Gutierrez, A.; Brois, S. J.; Brownawell, D. W.; Walker, T. O.

    1985-01-01

    Aqueous drilling fluids containing a minor amount of an additive composition featuring oxazolines of C/sub 1/-C/sub 30/ alkylthioglycolic acid. Such fluids are especially useful where reduced torque drilling fluids are needed. Another embodiment of this invention relates to a method of drilling utilizing the above-described fluids.

  3. Tetrasulfide extreme pressure lubricant additives

    SciTech Connect

    Gast, L.E.; Kenney, H.E.; Schwab, A.W.

    1980-08-19

    A novel class of compounds has been prepared comprising the tetrasulfides of /sup 18/C hydrocarbons, /sup 18/C fatty acids, and /sup 18/C fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

  4. Promoting Additive Acculturation in Schools.

    ERIC Educational Resources Information Center

    Gibson, Margaret A.

    1995-01-01

    A study focusing on 113 ninth graders of Mexican descent indicates that most students and their parents adhere to a strategy of additive acculturation (incorporating skills of the new culture and language), but that the school curriculum and general school climate devalue Mexican culture. (SLD)

  5. Individualized Additional Instruction for Calculus

    ERIC Educational Resources Information Center

    Takata, Ken

    2010-01-01

    College students enrolling in the calculus sequence have a wide variance in their preparation and abilities, yet they are usually taught from the same lecture. We describe another pedagogical model of Individualized Additional Instruction (IAI) that assesses each student frequently and prescribes further instruction and homework based on the…

  6. Out of bounds additive manufacturing

    DOE PAGESBeta

    Holshouser, Chris; Newell, Clint; Palas, Sid; Love, Lonnie J.; Kunc, Vlastimil; Lind, Randall F.; Lloyd, Peter D.; Rowe, John C.; Blue, Craig A.; Duty, Chad E.; et al

    2013-03-01

    Lockheed Martin and Oak Ridge National Laboratory are working on an additive manufacturing system capable of manufacturing components measured not in terms of inches or feet, but multiple yards in all dimensions with the potential to manufacture parts that are completely unbounded in size.

  7. Tinkertoy Color-Addition Device.

    ERIC Educational Resources Information Center

    Ferguson, Joe L.

    1995-01-01

    Describes construction and use of a simple home-built device, using an overhead projector, for use in demonstrations of the addition of various combinations of red, green, and blue light. Useful in connection with discussions of color, color vision, or color television. (JRH)

  8. Additional Financial Resources for Education.

    ERIC Educational Resources Information Center

    Hubbard, Ben C.

    This paper discusses the continuing need for additional educational funds and suggests that the only way to gain these funds is through concerted and persistent political efforts by supporters of education at both the federal and state levels. The author first points out that for many reasons declining enrollment may not decrease operating costs…

  9. Evaluation of certain food additives.

    PubMed

    2012-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium

  10. Evaluation of certain food additives.

    PubMed

    2012-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium

  11. Decontamination formulation with sorbent additive

    DOEpatents

    Tucker; Mark D. , Comstock; Robert H.

    2007-10-16

    A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

  12. Additive-free digital microfluidics.

    PubMed

    Freire, Sergio L S; Tanner, Brendan

    2013-07-16

    Digital microfluidics, a technique for manipulation of droplets, is becoming increasingly important for the development of miniaturized platforms for laboratory processes. Despite the enthusiasm, droplet motion is frequently hindered by the desorption of proteins or other analytes to surfaces. Current approaches to minimize this unwanted surface fouling involve the addition of extra species to the droplet or its surroundings, which might be problematic depending on the droplet content. Here, a new strategy is introduced to move droplets containing cells and other analytes on solid substrates, without extra moieties; in particular, droplets with bovine serum albumin could be moved at a concentration 2000 times higher than previously reported (without additives). This capability is achieved by using a soot-based superamphiphobic surface combined with a new device geometry, which favors droplet rolling. Contrasting with electrowetting, wetting forces are not required for droplet motion.

  13. Additive concentrates for distillate fuels

    SciTech Connect

    Rossi, A.; Lewtas, K.

    1985-08-27

    An additive concentrate for incorporation into wax containing petroleum fuel oil compositions to improve low temperature flow properties comprising an oil solution containing: 3% to 90 wt. % of a C30-C300 oil-soluble nitrogen compound wax crystal growth inhibitor having at least one straight C8-C40 alkyl chain and partial esters, and at least one mole per mole of an organic acid capable of hydrogen bonding to improve the solubility in the oil.

  14. Additive manufacturing of hybrid circuits

    DOE PAGESBeta

    Bell, Nelson S.; Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David M.; Hirschfeld, Deidre; Hall, Aaron Christopher

    2016-03-26

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects.more » Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. As a result, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.« less

  15. Evaluation of certain food additives.

    PubMed

    2009-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular, flavouring agents). A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (asparaginase from Aspergillus niger expressed in A. niger, calcium lignosulfonate (40-65), ethyl lauroyl arginate, paprika extract, phospholipase C expressed in Pichia pastoris, phytosterols, phytostanols and their esters, polydimethylsiloxane, steviol glycosides and sulfites [assessment of dietary exposure]) and 10 groups of related flavouring agents (aliphatic branched-chain saturated and unsaturated alcohols, aldehydes, acids and related esters; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; aliphatic secondary alcohols, ketones and related esters; alkoxy-substituted allylbenzenes present in foods and essential oils and used as flavouring agents; esters of aliphatic acyclic primary alcohols with aliphatic linear saturated carboxylic acids; furan-substituted aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; hydroxy- and alkoxy-substituted benzyl derivatives; and substances structurally related to menthol). Specifications for the following food additives were revised: canthaxanthin; carob bean gum and carob bean gum (clarified); chlorophyllin copper complexes, sodium and potassium salts; Fast Green FCF; guar gum and guar gum (clarified

  16. Fire-Retardant Polymeric Additives

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.

    2011-01-01

    Polyhydroxyamide (PHA) and polymethoxyamide (PMeOA) are fire-retardant (FR) thermoplastic polymers and have been found to be useful as an additive for imparting fire retardant properties to other compatible, thermoplastic polymers (including some elastomers). Examples of compatible flammable polymers include nylons, polyesters, and acrylics. Unlike most prior additives, PHA and PMeOA do not appreciably degrade the mechanical properties of the matrix polymer; indeed, in some cases, mechanical properties are enhanced. Also, unlike some prior additives, PHA and PMeOA do not decompose into large amounts of corrosive or toxic compounds during combustion and can be processed at elevated temperatures. PMeOA derivative formulations were synthesized and used as an FR additive in the fabrication of polyamide (PA) and polystyrene (PS) composites with notable reduction (>30 percent for PS) in peak heat release rates compared to the neat polymer as measured by a Cone Calorimeter (ASTM E1354). Synergistic effects were noted with nanosilica composites. These nanosilica composites had more than 50-percent reduction in peak heat release rates. In a typical application, a flammable thermoplastic, thermoplastic blend, or elastomer that one seeks to render flame-retardant is first dry-mixed with PHA or PMeOA or derivative thereof. The proportion of PHA or PMeOA or derivative in the mixture is typically chosen to lie between 1 and 20 weight percent. The dry blend can then be melt-extruded. The extruded polymer blend can further be extruded and/or molded into fibers, pipes, or any other of a variety of objects that may be required to be fire-retardant. The physical and chemical mechanisms which impart flame retardancy of the additive include inhibiting free-radical oxidation in the vapor phase, preventing vaporization of fuel (the polymer), and cooling through the formation of chemical bonds in either the vapor or the condensed phase. Under thermal stress, the cyclic hydroxyl/ methoxy

  17. HIP densification project. Final CRADA report

    SciTech Connect

    Franco-Ferreira, E.A.; Finkelstein, W.

    1997-08-29

    An investigation was conducted to evaluate the use of HIPed aluminum castings as near-net-shape blanks for large electrostatic focusing electrodes in ion lithography machines. The electrodes must have very smooth finishes which are free of pores and other defects. This has heretofore been achieved by rough-machining the blanks out of large forged aluminum billets and final diamond-turning. The use of a near-net-shape casting for the blank was expected to save a significant amount of money and time. The test was conducted on a single cast blank which was supplied by the Partner in the HIPed and stress relieved condition. Rough machining and diamond turning operations conducted by LMES/ER revealed that the casting contained unacceptably large defects. The conclusion was reached that HIPed aluminum castings in the large sizes and of the quality levels required would probably be unobtainable in a cost-effective manner. An alternative approach, using ring forgings assembled by electron beam welding was proposed and investigated by LMES/ER. Although an electrode blank was not obtained, the study indicated that this approach would be successful and cost-effective.

  18. Metal Additive Manufacturing: A Review

    NASA Astrophysics Data System (ADS)

    Frazier, William E.

    2014-06-01

    This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

  19. Individualized additional instruction for calculus

    NASA Astrophysics Data System (ADS)

    Takata, Ken

    2010-10-01

    College students enrolling in the calculus sequence have a wide variance in their preparation and abilities, yet they are usually taught from the same lecture. We describe another pedagogical model of Individualized Additional Instruction (IAI) that assesses each student frequently and prescribes further instruction and homework based on the student's performance. Our study compares two calculus classes, one taught with mandatory remedial IAI and the other without. The class with mandatory remedial IAI did significantly better on comprehensive multiple-choice exams, participated more frequently in classroom discussion and showed greater interest in theorem-proving and other advanced topics.

  20. The Mozart Effect: Additional Data.

    PubMed

    Hughes, John R.

    2002-04-01

    After the review of the Mozart effect was published in this journal (Hughes JR. Epilepsy Behav 2001;2:369-417), additional data from the music of Haydn and Liszt have been analyzed that may account for the decrease in seizure activity originally reported during Mozart music. Even with these added data Mozart music continued to score significantly higher than the selections from the other six composers in one of the important characteristics of this music, namely, the repetition of the melody. However Haydn's values were second highest among Mozart, J. S. Bach, Wagner, Beethoven, Chopin, and Liszt.

  1. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  2. Fuel Additives: Canada bans MMT

    SciTech Connect

    Sissell, K.

    1997-04-16

    The Canadian Senate voted late last week to ban use of the manganese-based fuel additive MMT, produced only in the US by Ethyl. MMT, which has been sold in Canada for the past 20 years and accounts for about half of Ethyl`s Canadian sales, has been criticized by environmentalists, who have raised public health concerns, and automakers, who say it harms emission control systems. {open_quotes}Canada`s vote is a great victory for public health and the environment,{close_quotes} says Environmental Defense Fund executive director Fred Krupp. {open_quotes}The US should move swiftly to follow suit and suspend sales of MMT until adequate toxicity testing on the additive is completed.{close_quotes} EPA had refused to approve MMT for sale because of health concerns but was compelled to do so by a December 1995 court ruling. Ethyl asserts the ban violates Canada`s obligations under Nafta and says it will file a damage claim with the Nafta arbitration panel.

  3. Neutron Characterization for Additive Manufacturing

    NASA Technical Reports Server (NTRS)

    Watkins, Thomas; Bilheux, Hassina; An, Ke; Payzant, Andrew; DeHoff, Ryan; Duty, Chad; Peter, William; Blue, Craig; Brice, Craig A.

    2013-01-01

    Oak Ridge National Laboratory (ORNL) is leveraging decades of experience in neutron characterization of advanced materials together with resources such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) shown in Fig. 1 to solve challenging problems in additive manufacturing (AM). Additive manufacturing, or three-dimensional (3-D) printing, is a rapidly maturing technology wherein components are built by selectively adding feedstock material at locations specified by a computer model. The majority of these technologies use thermally driven phase change mechanisms to convert the feedstock into functioning material. As the molten material cools and solidifies, the component is subjected to significant thermal gradients, generating significant internal stresses throughout the part (Fig. 2). As layers are added, inherent residual stresses cause warping and distortions that lead to geometrical differences between the final part and the original computer generated design. This effect also limits geometries that can be fabricated using AM, such as thin-walled, high-aspect- ratio, and overhanging structures. Distortion may be minimized by intelligent toolpath planning or strategic placement of support structures, but these approaches are not well understood and often "Edisonian" in nature. Residual stresses can also impact component performance during operation. For example, in a thermally cycled environment such as a high-pressure turbine engine, residual stresses can cause components to distort unpredictably. Different thermal treatments on as-fabricated AM components have been used to minimize residual stress, but components still retain a nonhomogeneous stress state and/or demonstrate a relaxation-derived geometric distortion. Industry, federal laboratory, and university collaboration is needed to address these challenges and enable the U.S. to compete in the global market. Work is currently being conducted on AM technologies at the ORNL

  4. Additives in fibers and fabrics.

    PubMed

    Barker, R H

    1975-06-01

    The additives and contaminants which occur in textile fibers vary widely, depending on the type of fiber and the pretreatment which it has received. Synthetic fibers such as nylon and polyester contain trace amounts of contaminants such as catalysts and catalyst deactivators which remain after the synthesis of the basic polymers. In addition, there are frequently a number of materials which are added to perform specific functions in almost all man-made fibers. Examples of these would include traces of metals or metal salts used as tracers for identification of specific lots of fiber, TiO2 or similar materials added as delustrants, and a host of organic species added for such special purposes as antistatic agents or flame retardants. There may also be considerable quantities of residual monomer or small oligomers dissolved in the polymer matrix. The situation becomes even more complex after the fibers are converted into fabric form. Numerous materials are applied at various stages of fabric preparation to act as lubricants, sizing agents, antistats, bleaches, and wetting agents to facilitate the processing, but these are normally removed before the fabric reaches the cutters of the ultimate consumers and therefore usually do not constitute potential hazards. However, there are many other chemical agents which are frequently added during the later stages of fabric preparation and which are not designed to be removed. Aside from dyes and printing pigments, the most common additive for apparel fabrics is a durable press treatment. This generally involves the use of materials capable of crosslinking cellulosics by reacting through such functions as N-methylolated amides or related compounds such as ureas and carbamates. These materials pose some potential hazards due to both the nitrogenous bases and the formaldehyde which they usually release. There is usually also some residual catalyst in fabrics which have received such treatments. Other types of chemical treatments

  5. Additives in fibers and fabrics.

    PubMed Central

    Barker, R H

    1975-01-01

    The additives and contaminants which occur in textile fibers vary widely, depending on the type of fiber and the pretreatment which it has received. Synthetic fibers such as nylon and polyester contain trace amounts of contaminants such as catalysts and catalyst deactivators which remain after the synthesis of the basic polymers. In addition, there are frequently a number of materials which are added to perform specific functions in almost all man-made fibers. Examples of these would include traces of metals or metal salts used as tracers for identification of specific lots of fiber, TiO2 or similar materials added as delustrants, and a host of organic species added for such special purposes as antistatic agents or flame retardants. There may also be considerable quantities of residual monomer or small oligomers dissolved in the polymer matrix. The situation becomes even more complex after the fibers are converted into fabric form. Numerous materials are applied at various stages of fabric preparation to act as lubricants, sizing agents, antistats, bleaches, and wetting agents to facilitate the processing, but these are normally removed before the fabric reaches the cutters of the ultimate consumers and therefore usually do not constitute potential hazards. However, there are many other chemical agents which are frequently added during the later stages of fabric preparation and which are not designed to be removed. Aside from dyes and printing pigments, the most common additive for apparel fabrics is a durable press treatment. This generally involves the use of materials capable of crosslinking cellulosics by reacting through such functions as N-methylolated amides or related compounds such as ureas and carbamates. These materials pose some potential hazards due to both the nitrogenous bases and the formaldehyde which they usually release. There is usually also some residual catalyst in fabrics which have received such treatments. Other types of chemical treatments

  6. An Additive Manufacturing Test Artifact.

    PubMed

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system. PMID:26601039

  7. An Additive Manufacturing Test Artifact

    PubMed Central

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system. PMID:26601039

  8. SIPSEY WILDERNESS AND ADDITIONS, ALABAMA.

    USGS Publications Warehouse

    Schweinfurth, Stanley P.; Mory, Peter C.

    1984-01-01

    On the basis of geologic, geochemical, and mineral surveys the Sipsey Wilderness and additions are deemed to have little promise for the occurrence of metallic mineral resources. Although limestone, shale, and sandstone resources that occur in the area are physically suitable for a variety of uses, similar materials are available outside the area closer to transportation routes and potential markets. A small amount of coal has been identified in the area, occurring as nonpersistent beds less than 28 in. thick. Oil and (or) natural gas resources may be present if suitable structural traps exist in the subsurface. Therefore, the area has a probable oil and gas potential. Small amounts of asphaltic sandstone and limestone, commonly referred to as tar sands, may also occur in the subsurface. 5 refs.

  9. An Additive Manufacturing Test Artifact.

    PubMed

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system.

  10. A novel addition polyimide adhesive

    NASA Technical Reports Server (NTRS)

    St.clair, T. L.; Progar, D. J.

    1981-01-01

    An addition polyimide adhesive, LARC 13, was developed which shows promise for bonding both titanium and composites for applications which require service temperatures in excess of 533 K. The LARC 13 is based on an oligomeric bis nadimide containing a meta linked aromatic diamine. The adhesive melts prior to polymerization due to its oligomeric nature, thereby allowing it to be processed at 344 kPa or less. Therefore, LARC 13 is ideal for the bonding of honeycomb sandwich structures. After melting, the resin thermosets during the cure of the nadic endcaps to a highly crosslinked system. Few volatiles are evolved, thus allowing large enclosed structures to be bonded. Preparation of the adhesive as well as bonding, aging, and testing of lap shear and honeycomb samples are discussed.

  11. Adverse reactions to food additives.

    PubMed

    Simon, R A

    1986-01-01

    There are thousands of agents that are intentionally added to the food that we consume. These include preservatives, stabilizers, conditioners, thickeners, colorings, flavorings, sweeteners, antioxidants, etc. etc. Yet only a surprisingly small number have been associated with hypersensitivity reactions. Amongst all the additives, FD&C dyes have been most frequently associated with adverse reactions. Tartrazine is the most notorious of them all; however, critical review of the medical literature and current Scripps Clinic studies would indicate that tartrazine has been confirmed to be at best only occasionally associated with flares of urticaria or asthma. There is no convincing evidence in the literature of reactivity to the other azo or nonazo dyes. This can also be said of BHA/BHT, nitrites/nitrates and sorbates. Parabens have been shown to elicit IgE mediated hypersensitivity reactions when used as pharmaceutical preservatives; however, as with the other additives noted above, ingested parabens have only occasionally been associated with adverse reactions. MSG, the cause of the 'Chinese restaurant syndrome' has only been linked to asthma in one report. Sulfiting agents used primarily as food fresheners and to control microbial growth in fermented beverages have been established as the cause of any where from mild to severe and even fatal reactions in at least 5% of the asthmatic population. Other reactions reported to follow sulfite ingestion include anaphylaxis, gastro intestinal complaints and dermatological eruptions. The prevalence of these non asthmatic reactions is unknown. The mechanism of sulfite sensitive asthma is also unknown but most likely involves hyperreactivity to inhale SO2 in the great majority of cases; however, there are reports of IgE mediated reactions and other sulfite sensitive asthmatics have been found with low levels of sulfite oxidase; necessary to oxidize endogenous sulfite to sulfate.

  12. Additive attacks on speaker recognition

    NASA Astrophysics Data System (ADS)

    Farrokh Baroughi, Alireza; Craver, Scott

    2014-02-01

    Speaker recognition is used to identify a speaker's voice from among a group of known speakers. A common method of speaker recognition is a classification based on cepstral coefficients of the speaker's voice, using a Gaussian mixture model (GMM) to model each speaker. In this paper we try to fool a speaker recognition system using additive noise such that an intruder is recognized as a target user. Our attack uses a mixture selected from a target user's GMM model, inverting the cepstral transformation to produce noise samples. In our 5 speaker data base, we achieve an attack success rate of 50% with a noise signal at 10dB SNR, and 95% by increasing noise power to 0dB SNR. The importance of this attack is its simplicity and flexibility: it can be employed in real time with no processing of an attacker's voice, and little computation is needed at the moment of detection, allowing the attack to be performed by a small portable device. For any target user, knowing that user's model or voice sample is sufficient to compute the attack signal, and it is enough that the intruder plays it while he/she is uttering to be classiffed as the victim.

  13. Additive Transforms Paint into Insulation

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tech Traders Inc. sought assistance developing low-cost, highly effective coatings and paints that created useful thermal reflectance and were safe and non-toxic. In cooperation with a group of engineers at Kennedy Space Center., Tech Traders created Insuladd, a powder additive made up of microscopic, inert gas-filled, ceramic microspheres that can be mixed into ordinary interior or exterior paint, allowing the paint to act like a layer of insulation. When the paint dries, this forms a radiant heat barrier, turning the ordinary house paint into heat-reflecting thermal paint. According to Tech Traders, the product works with all types of paints and coatings and will not change the coverage rate, application, or adhesion of the paint. Other useful applications include feed storage silos to help prevent feed spoilage, poultry hatcheries to reduce the summer heat and winter cold effects, and on military vehicles and ships. Tech Traders has continued its connection to the aerospace community by recently providing Lockheed Martin Corporation with one of its thermal products for use on the F-22 Raptor.

  14. Sustainability Characterization for Additive Manufacturing

    PubMed Central

    Mani, Mahesh; Lyons, Kevin W; Gupta, SK

    2014-01-01

    Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use for parts production since industries primarily depend on established standards in processes and material selection to ensure the consistency and quality. Inability to compare AM performance against traditional manufacturing methods can be a barrier for implementing AM processes. AM process sustainability has become a driver due to growing environmental concerns for manufacturing. This has reinforced the importance to understand and characterize AM processes for sustainability. Process characterization for sustainability will help close the gaps for comparing AM performance to traditional manufacturing methods. Based on a literature review, this paper first examines the potential environmental impacts of AM. A methodology for sustainability characterization of AM is then proposed to serve as a resource for the community to benchmark AM processes for sustainability. Next, research perspectives are discussed along with relevant standardization efforts. PMID:26601038

  15. Additively manufactured porous tantalum implants.

    PubMed

    Wauthle, Ruben; van der Stok, Johan; Amin Yavari, Saber; Van Humbeeck, Jan; Kruth, Jean-Pierre; Zadpoor, Amir Abbas; Weinans, Harrie; Mulier, Michiel; Schrooten, Jan

    2015-03-01

    The medical device industry's interest in open porous, metallic biomaterials has increased in response to additive manufacturing techniques enabling the production of complex shapes that cannot be produced with conventional techniques. Tantalum is an important metal for medical devices because of its good biocompatibility. In this study selective laser melting technology was used for the first time to manufacture highly porous pure tantalum implants with fully interconnected open pores. The architecture of the porous structure in combination with the material properties of tantalum result in mechanical properties close to those of human bone and allow for bone ingrowth. The bone regeneration performance of the porous tantalum was evaluated in vivo using an orthotopic load-bearing bone defect model in the rat femur. After 12 weeks, substantial bone ingrowth, good quality of the regenerated bone and a strong, functional implant-bone interface connection were observed. Compared to identical porous Ti-6Al-4V structures, laser-melted tantalum shows excellent osteoconductive properties, has a higher normalized fatigue strength and allows for more plastic deformation due to its high ductility. It is therefore concluded that this is a first step towards a new generation of open porous tantalum implants manufactured using selective laser melting.

  16. Additively manufactured porous tantalum implants.

    PubMed

    Wauthle, Ruben; van der Stok, Johan; Amin Yavari, Saber; Van Humbeeck, Jan; Kruth, Jean-Pierre; Zadpoor, Amir Abbas; Weinans, Harrie; Mulier, Michiel; Schrooten, Jan

    2015-03-01

    The medical device industry's interest in open porous, metallic biomaterials has increased in response to additive manufacturing techniques enabling the production of complex shapes that cannot be produced with conventional techniques. Tantalum is an important metal for medical devices because of its good biocompatibility. In this study selective laser melting technology was used for the first time to manufacture highly porous pure tantalum implants with fully interconnected open pores. The architecture of the porous structure in combination with the material properties of tantalum result in mechanical properties close to those of human bone and allow for bone ingrowth. The bone regeneration performance of the porous tantalum was evaluated in vivo using an orthotopic load-bearing bone defect model in the rat femur. After 12 weeks, substantial bone ingrowth, good quality of the regenerated bone and a strong, functional implant-bone interface connection were observed. Compared to identical porous Ti-6Al-4V structures, laser-melted tantalum shows excellent osteoconductive properties, has a higher normalized fatigue strength and allows for more plastic deformation due to its high ductility. It is therefore concluded that this is a first step towards a new generation of open porous tantalum implants manufactured using selective laser melting. PMID:25500631

  17. Sustainability Characterization for Additive Manufacturing.

    PubMed

    Mani, Mahesh; Lyons, Kevin W; Gupta, S K

    2014-01-01

    Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use for parts production since industries primarily depend on established standards in processes and material selection to ensure the consistency and quality. Inability to compare AM performance against traditional manufacturing methods can be a barrier for implementing AM processes. AM process sustainability has become a driver due to growing environmental concerns for manufacturing. This has reinforced the importance to understand and characterize AM processes for sustainability. Process characterization for sustainability will help close the gaps for comparing AM performance to traditional manufacturing methods. Based on a literature review, this paper first examines the potential environmental impacts of AM. A methodology for sustainability characterization of AM is then proposed to serve as a resource for the community to benchmark AM processes for sustainability. Next, research perspectives are discussed along with relevant standardization efforts.

  18. The effect of glass additives on the microwave dielectric properties of Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} ceramics

    SciTech Connect

    Surendran, K.P.; Mohanan, P.; Sebastian, M.T. . E-mail: mailadils@yahoo.com

    2004-11-01

    The effect of glass additives on the densification, phase evolution, microstructure and microwave dielectric properties of Ba(Mg{sub 1/3}Ta{sub 2/3})O{sub 3} (BMT) was investigated. Different weight percentages of quenched glass such as B{sub 2}O{sub 3}, SiO{sub 2}, B{sub 2}O{sub 3}-SiO{sub 2}, ZnO-B{sub 2}O{sub 3}, 5ZnO-2B{sub 2}O{sub 3}, Al{sub 2}O{sub 3}-SiO{sub 2}, Na{sub 2}O-2B{sub 2}O{sub 3}.10H{sub 2}O, BaO-B{sub 2}O{sub 3}-SiO{sub 2}, MgO-B{sub 2}O{sub 3}-SiO{sub 2}, PbO-B{sub 2}O{sub 3}-SiO{sub 2}, ZnO-B{sub 2}O{sub 3}-SiO{sub 2} and 2MgO-Al{sub 2}O{sub 3}-5SiO{sub 2} were added to calcined BMT precursor. The sintering temperature of the glass-added BMT samples were lowered down to 1300 deg. C compared to solid-state sintering where the temperature was 1650{sup o}C. The formation of high temperature satellite phases such as Ba{sub 5}Ta{sub 4}O{sub 15} and Ba{sub 7}Ta{sub 6}O{sub 22} were found to be suppressed by the glass addition. Addition of glass systems such as B{sub 2}O{sub 3}, ZnO-B{sub 2}O{sub 3}, 5ZnO-2B{sub 2}O{sub 3} and ZnO-B{sub 2}O{sub 3}-SiO{sub 2} improved the densification and microwave dielectric properties. Other glasses were found to react with BMT to form low-Q phases which prevented densification. The microwave dielectric properties of undoped BMT with a densification of 93.1% of the theoretical density were {epsilon}r=24.8, {tau}f=8ppm/{sup o}C and Q{sub u}xf=80,000GHz. The BMT doped with 1.0wt% of B{sub 2}O{sub 3} has Q{sub u}xf=124,700GHz, {epsilon}r=24.2, and {tau}f=-1.3ppm/ deg/ C. The unloaded Q factor of 0.2wt% ZnO-B{sub 2}O{sub 3}-doped BMT was 136,500GHz while that of 1.0wt% of 5ZnO-2B{sub 2}O{sub 3} added ceramic was Q{sub u}xf=141,800GHz. The best microwave quality factor was observed for ZnO-B{sub 2}O{sub 3}-SiO{sub 2} (ZBS) glass-added ceramics which can act as a perfect liquid-phase medium for the sintering of BMT. The microwave dielectric properties of 0.2wt% ZBS-added BMT dielectric was Q{sub u}xf=152,800GHz, {epsilon

  19. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  20. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  1. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  2. Septic tank additive impacts on microbial populations.

    PubMed

    Pradhan, S; Hoover, M T; Clark, G H; Gumpertz, M; Wollum, A G; Cobb, C; Strock, J

    2008-01-01

    Environmental health specialists, other onsite wastewater professionals, scientists, and homeowners have questioned the effectiveness of septic tank additives. This paper describes an independent, third-party, field scale, research study of the effects of three liquid bacterial septic tank additives and a control (no additive) on septic tank microbial populations. Microbial populations were measured quarterly in a field study for 12 months in 48 full-size, functioning septic tanks. Bacterial populations in the 48 septic tanks were statistically analyzed with a mixed linear model. Additive effects were assessed for three septic tank maintenance levels (low, intermediate, and high). Dunnett's t-test for tank bacteria (alpha = .05) indicated that none of the treatments were significantly different, overall, from the control at the statistical level tested. In addition, the additives had no significant effects on septic tank bacterial populations at any of the septic tank maintenance levels. Additional controlled, field-based research iswarranted, however, to address additional additives and experimental conditions.

  3. Investigating the addition of SiO₂-CaO-ZnO-Na₂O-TiO₂ bioactive glass to hydroxyapatite: Characterization, mechanical properties and bioactivity.

    PubMed

    Yatongchai, Chokchai; Placek, Lana M; Curran, Declan J; Towler, Mark R; Wren, Anthony W

    2015-11-01

    Hydroxyapatite (Ca10(PO4)6(OH)2) is widely investigated as an implantable material for hard tissue restoration due to its osteoconductive properties. However, hydroxyapatite in bulk form is limited as its mechanical properties are insufficient for load-bearing orthopedic applications. Attempts have been made to improve the mechanical properties of hydroxyapatite, by incorporating ceramic fillers, but the resultant composite materials require high sintering temperatures to facilitate densification, leading to the decomposition of hydroxyapatite into tricalcium phosphate, tetra-calcium phosphate and CaO phases. One method of improving the properties of hydroxyapatite is to incorporate bioactive glass particles as a second phase. These typically have lower softening points which could possibly facilitate sintering at lower temperatures. In this work, a bioactive glass (SiO2-CaO-ZnO-Na2O-TiO2) is incorporated (10, 20 and 30 wt%) into hydroxyapatite as a reinforcing phase. X-ray diffraction confirmed that no additional phases (other than hydroxyapatite) were formed at a sintering temperature of 560 ℃ with up to 30 wt% glass addition. The addition of the glass phase increased the % crystallinity and the relative density of the composites. The biaxial flexural strength increased to 36 MPa with glass addition, and there was no significant change in hardness as a function of maturation. The pH of the incubation media increased to pH 10 or 11 through glass addition, and ion release profiles determined that Si, Na and P were released from the composites. Calcium phosphate precipitation was encouraged in simulated body fluid with the incorporation of the bioactive glass phase, and cell culture testing in MC-3T3 osteoblasts determined that the composite materials did not significantly reduce cell viability.

  4. Investigating the addition of SiO₂-CaO-ZnO-Na₂O-TiO₂ bioactive glass to hydroxyapatite: Characterization, mechanical properties and bioactivity.

    PubMed

    Yatongchai, Chokchai; Placek, Lana M; Curran, Declan J; Towler, Mark R; Wren, Anthony W

    2015-11-01

    Hydroxyapatite (Ca10(PO4)6(OH)2) is widely investigated as an implantable material for hard tissue restoration due to its osteoconductive properties. However, hydroxyapatite in bulk form is limited as its mechanical properties are insufficient for load-bearing orthopedic applications. Attempts have been made to improve the mechanical properties of hydroxyapatite, by incorporating ceramic fillers, but the resultant composite materials require high sintering temperatures to facilitate densification, leading to the decomposition of hydroxyapatite into tricalcium phosphate, tetra-calcium phosphate and CaO phases. One method of improving the properties of hydroxyapatite is to incorporate bioactive glass particles as a second phase. These typically have lower softening points which could possibly facilitate sintering at lower temperatures. In this work, a bioactive glass (SiO2-CaO-ZnO-Na2O-TiO2) is incorporated (10, 20 and 30 wt%) into hydroxyapatite as a reinforcing phase. X-ray diffraction confirmed that no additional phases (other than hydroxyapatite) were formed at a sintering temperature of 560 ℃ with up to 30 wt% glass addition. The addition of the glass phase increased the % crystallinity and the relative density of the composites. The biaxial flexural strength increased to 36 MPa with glass addition, and there was no significant change in hardness as a function of maturation. The pH of the incubation media increased to pH 10 or 11 through glass addition, and ion release profiles determined that Si, Na and P were released from the composites. Calcium phosphate precipitation was encouraged in simulated body fluid with the incorporation of the bioactive glass phase, and cell culture testing in MC-3T3 osteoblasts determined that the composite materials did not significantly reduce cell viability. PMID:26116020

  5. Influence of Ni nanoparticle addition and spark plasma sintering on the TiNiSn–Ni system: Structure, microstructure, and thermoelectric properties

    SciTech Connect

    Birkel, Christina S.; Douglas, Jason E.; Lettiere, Bethany R.; Seward, Gareth; Zhang, Yichi; Pollock, Tresa M.; Seshadri, Ram; Stucky, Galen D.

    2013-12-01

    The electronic and thermal properties of thermoelectric materials are highly dependent on their microstructure and therefore on the preparation conditions, including the initial synthesis and, if applicable, densification of the obtained powders. Introduction of secondary phases on the nano- and/or microscale is widely used to improve the thermoelectric figure of merit by reduction of the thermal conductivity. In order to understand the effect of the preparation technique on structure and properties, we have studied the thermoelectric properties of the well-known half-Heusler TiNiSn with addition of a small amount of nickel nanoparticles. The different parameters are the initial synthesis (levitation melting and microwave heating), the amount of nickel nanoparticles added and the exact pressing profile using spark plasma sintering. The resulting materials have been characterized by synchrotron X-ray diffraction and microprobe measurements and their thermoelectric properties are investigated. We found the lowest (lattice) thermal conductivity in samples with full-Heusler TiNi2Sn and Ni3Sn4 as secondary phases.

  6. Additive Manufacturing of Aerospace Propulsion Components

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.; Grady, Joseph E.; Carter, Robert

    2015-01-01

    The presentation will provide an overview of ongoing activities on additive manufacturing of aerospace propulsion components, which included rocket propulsion and gas turbine engines. Future opportunities on additive manufacturing of hybrid electric propulsion components will be discussed.

  7. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  8. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  9. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  10. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  11. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  12. [Safety of food additives in Japan].

    PubMed

    Ito, Sumio

    2011-01-01

    Recently, many accidents relating to food happened in Japan. The consumer's distrust for food, food companies, and the administration is increasing. The consumer especially has an extreme refusal feeling for chemicals such as food additives and agricultural chemicals, and begins to request agricultural chemical-free vegetables and food additive-free food. Food companies also state no agricultural chemicals and no food additives to correspond with consumers' request and aim at differentiating. The food additive is that the Ministry of Health, Labour and Welfare specifies the one that person's health might not be ruined by providing for Food Sanitation Law Article 10 in our country. The standard for food additives and standard for use of food additives are provided according to regulations of Food Sanitation Law Article 11. Therefore, it is thought that the food additive used is safe now. Then, it reports on the procedure and the safety examination, etc. in our country for designation for food additive this time.

  13. 42 CFR 412.115 - Additional payments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Payment Systems § 412.115 Additional payments. (a) Bad debts. An additional payment is made to each hospital in accordance with § 413.89 of this chapter for bad debts attributable to deductible...

  14. 42 CFR 412.115 - Additional payments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Payment Systems § 412.115 Additional payments. (a) Bad debts. An additional payment is made to each hospital in accordance with § 413.89 of this chapter for bad debts attributable to deductible...

  15. 42 CFR 412.115 - Additional payments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Payment Systems § 412.115 Additional payments. (a) Bad debts. An additional payment is made to each hospital in accordance with § 413.89 of this chapter for bad debts attributable to deductible...

  16. 17 CFR 230.408 - Additional information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Additional information. 230... RULES AND REGULATIONS, SECURITIES ACT OF 1933 General Requirements § 230.408 Additional information. (a) In addition to the information expressly required to be included in a registration statement,...

  17. 17 CFR 230.408 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 2 2013-04-01 2013-04-01 false Additional information. 230... RULES AND REGULATIONS, SECURITIES ACT OF 1933 General Requirements § 230.408 Additional information. (a) In addition to the information expressly required to be included in a registration statement,...

  18. 47 CFR 25.111 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Additional information. 25.111 Section 25.111... Applications and Licenses General Application Filing Requirements § 25.111 Additional information. (a) The Commission may request from any party at any time additional information concerning any application, or...

  19. 10 CFR 810.14 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Additional information. 810.14 Section 810.14 Energy DEPARTMENT OF ENERGY ASSISTANCE TO FOREIGN ATOMIC ENERGY ACTIVITIES § 810.14 Additional information. The... activity to submit additional information....

  20. 47 CFR 25.111 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Additional information. 25.111 Section 25.111... Applications and Licenses General Application Filing Requirements § 25.111 Additional information. (a) The Commission may request from any party at any time additional information concerning any application, or...

  1. 10 CFR 725.13 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Additional information. 725.13 Section 725.13 Energy DEPARTMENT OF ENERGY PERMITS FOR ACCESS TO RESTRICTED DATA Applications § 725.13 Additional information. The... and before the termination of the permit, require additional information in order to enable the...

  2. 47 CFR 25.111 - Additional information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Additional information. 25.111 Section 25.111... Applications and Licenses General Application Filing Requirements § 25.111 Additional information. (a) The Commission may request from any party at any time additional information concerning any application, or...

  3. 20 CFR 802.215 - Additional briefs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Additional briefs. 802.215 Section 802.215 Employees' Benefits BENEFITS REVIEW BOARD, DEPARTMENT OF LABOR RULES OF PRACTICE AND PROCEDURE Prereview Procedures Initial Processing § 802.215 Additional briefs. Additional briefs may be filed or ordered in...

  4. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The Commission may, by rule, regulation, or order, impose upon any licensee such requirements, in addition...

  5. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The Commission may, by rule, regulation, or order, impose upon any licensee such requirements, in addition...

  6. 77 FR 53180 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... INFORMATION: Additions On 6/15/2012 (77 FR 35942-35944) and 6/29/2012 (77 FR 38775-38776), the Committee for... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase from People who are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  7. 76 FR 35415 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ... INFORMATION: Additions On 4/29/2011 (76 FR 23998), the Committee for Purchase From People Who Are Blind or... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  8. 78 FR 9386 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-08

    ... INFORMATION: Addition On 11/30/2012 (77 FR 71400-71401), the Committee for Purchase From People Who Are Blind... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  9. 77 FR 31335 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... . SUPPLEMENTARY INFORMATION: Additions On March 16, 2012 (77 FR 15736) and March 23, 2012 (77 FR 17035), the... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  10. 76 FR 19751 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-08

    ... INFORMATION: Addition On 1/28/2011 (76 FR 5142-5143), the Committee for Purchase From People Who Are Blind or... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  11. 75 FR 4784 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-29

    ... INFORMATION: Addition On 11/16/2009 (74 FR 58949-58950), the Committee for Purchase From People Who Are Blind... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  12. 76 FR 23997 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ... INFORMATION: Addition On 2/25/2011 (76 FR 10571), the Committee for Purchase From People Who Are Blind or... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  13. 75 FR 22745 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-30

    ... INFORMATION: Additions On 10/23/2009 (74 FR 54783-54784) and 3/5/2010 (75 FR 10223-10224), the Committee for... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  14. 77 FR 71400 - Procurement List, Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-30

    ... . SUPPLEMENTARY INFORMATION: Additions On 8/24/2012 (77 FR 51522-51523) and 10/5/2012 (77 FR 60969), the Committee... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List, Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  15. 75 FR 72815 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-26

    ... INFORMATION: Additions On 6/4/2010 (75 FR 31768-31769) and 10/1/2010 (75 FR 60739-60740), the Committee for... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  16. 77 FR 59595 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ... . SUPPLEMENTARY INFORMATION: Additions On 7/9/2012 (77 FR 40344-40345) and 7/20/2012 (77 FR 42701-42702), the... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  17. 77 FR 34025 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ... INFORMATION: ] Addition On 4/132012 (77 FR 22289-22290), the Committee for Purchase From People Who Are Blind... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  18. 78 FR 2378 - Procurement List, Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-11

    ... INFORMATION: Addition On 11/9/2012 (77 FR 67343-67344), the Committee for Purchase From People Who Are Blind... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List, Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  19. 76 FR 54741 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... INFORMATION: Additions On 7/8/2011 (76 FR 40342-40343), the Committee for Purchase From People Who Are Blind... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  20. Polymeric Additives For Graphite/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.

    1990-01-01

    Report describes experimental studies of properties of several graphite/epoxy composites containing polymeric additives as flexibilizing or toughening agents. Emphasizes effects of brominated polymeric additives (BPA's) with or without carboxy-terminated butadiene acrylonitrile rubber. Reviews effects of individual and combined additives on fracture toughnesses, environmental stabilities, hot/wet strengths, thermomechanical behaviors, and other mechanical properties of composites.

  1. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  2. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  3. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  4. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  5. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  6. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  7. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 13 2011-01-01 2009-01-01 true Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  8. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 13 2013-01-01 2013-01-01 false Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  9. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 13 2011-01-01 2009-01-01 true Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  10. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 13 2013-01-01 2013-01-01 false Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  11. 24 CFR 964.410 - Additional definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Additional definitions. 964.410... Additional definitions. The following additional definitions apply to this subpart only: Directly assisted... assisted by a public housing agency; (2) Whose name appears on the lease; and (3) Is eighteen years of...

  12. 24 CFR 964.410 - Additional definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Additional definitions. 964.410... Additional definitions. The following additional definitions apply to this subpart only: Directly assisted... assisted by a public housing agency; (2) Whose name appears on the lease; and (3) Is eighteen years of...

  13. 24 CFR 964.410 - Additional definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Additional definitions. 964.410... Additional definitions. The following additional definitions apply to this subpart only: Directly assisted... assisted by a public housing agency; (2) Whose name appears on the lease; and (3) Is eighteen years of...

  14. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The Commission may, by rule, regulation, or order, impose upon any licensee such requirements, in addition to those established in...

  15. 44 CFR 6.81 - Additional copies.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Additional copies. 6.81... HOMELAND SECURITY GENERAL IMPLEMENTATION OF THE PRIVACY ACT OF 1974 Fees § 6.81 Additional copies. A reasonable number of additional copies shall be provided for the applicable fee to a requestor who...

  16. Cincinnati Big Area Additive Manufacturing (BAAM)

    SciTech Connect

    Duty, Chad E.; Love, Lonnie J.

    2015-03-04

    Oak Ridge National Laboratory (ORNL) worked with Cincinnati Incorporated (CI) to demonstrate Big Area Additive Manufacturing which increases the speed of the additive manufacturing (AM) process by over 1000X, increases the size of parts by over 10X and shows a cost reduction of over 100X. ORNL worked with CI to transition the Big Area Additive Manufacturing (BAAM) technology from a proof-of-principle (TRL 2-3) demonstration to a prototype product stage (TRL 7-8).

  17. 42 CFR 57.217 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.217 Additional conditions. The Secretary may with respect to any agreement entered into...

  18. 42 CFR 57.217 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.217 Additional conditions. The Secretary may with respect to any agreement entered into...

  19. 42 CFR 57.217 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.217 Additional conditions. The Secretary may with respect to any agreement entered into...

  20. 42 CFR 57.217 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.217 Additional conditions. The Secretary may with respect to any agreement entered into...

  1. 42 CFR 57.217 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... TEACHING FACILITIES, EDUCATIONAL IMPROVEMENTS, SCHOLARSHIPS AND STUDENT LOANS Health Professions Student Loans § 57.217 Additional conditions. The Secretary may with respect to any agreement entered into...

  2. Allergic and immunologic reactions to food additives.

    PubMed

    Gultekin, Fatih; Doguc, Duygu Kumbul

    2013-08-01

    For centuries, food additives have been used for flavouring, colouring and extension of the useful shelf life of food, as well as the promotion of food safety. During the last 20 years, the studies implicating the additives contained in foods and medicine as a causative factor of allergic reactions have been proliferated considerably. In this review, we aimed to overview all of the food additives which were approved to consume in EU and find out how common and serious allergic reactions come into existence following the consuming of food additives.

  3. Classification of additives for organic photovoltaic devices.

    PubMed

    Machui, Florian; Maisch, Philipp; Burgués-Ceballos, Ignasi; Langner, Stefan; Krantz, Johannes; Ameri, Tayebeh; Brabec, Christoph J

    2015-04-27

    The use of additives to improve the performance of organic photovoltaic cells has been intensely researched in recent years. However, so far, no system has been reported for the classification of additives and their functions. In this report, a system for classifying additives according to the fundamental mechanism by which they influence microstructure formation for P3HT:PCBM is suggested. The major parameters used for their classification are solubility and drying kinetics. Both are discussed in detail and their consequences on processing are analyzed. Furthermore, a general mechanism to classify the impact of additives on structure formation is suggested and discussed for different materials relevant to organic photovoltaic devices.

  4. 15 CFR 292.6 - Additional requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... OF STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE NIST EXTRAMURAL PROGRAMS MANUFACTURING EXTENSION PARTNERSHIP; INFRASTRUCTURE DEVELOPMENT PROJECTS § 292.6 Additional requirements. Federal policies...

  5. Effects of SnO2, WO3, and ZrO2 addition on the magnetic and mechanical properties of NiCuZn ferrites

    NASA Astrophysics Data System (ADS)

    Wang, Sea-Fue; Yang, Hsiao-Ching; Hsu, Yung-Fu; Hsieh, Chung-Kai

    2015-01-01

    In this study, the effects of SnO2, WO3 and ZrO2 addition at levels up to 5 wt% on the magnetic and mechanical properties of Ni0.5Cu0.3Zn0.2Fe2O4 ceramics were investigated. Only Ni0.5Cu0.3Zn0.2Fe2O4 ceramic with a SnO2 addition of ≥3.5 wt% required a densification temperature of 1150 °C, while the others reached maximum densification at 1075 °C. All samples revealed a pure spinel phase and a uniform microstructure, except for the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic with the WO3 addition, which showed an exaggerated grain growth accompanied with a small amount of needle-shaped Cu0.85Zn0.15WO4 second phase. The fracture mode in the pure Ni0.5Cu0.3Zn0.2Fe2O4 ceramic revealed a transgranular phase, as the CuO second phase increased the grain boundary strength; the Ni0.5Cu0.3Zn0.2Fe2O4 ceramics sintered with 5 wt% additives showed an intergranular phase. The Vickers hardness and the bending strength of the Ni0.5Cu0.3Zn0.2Fe2O4 ceramic were 733.6 and 62.0 MPa, respectively. The Vickers hardness of the ferrite with added SnO2 or ZrO2 showed only a slight improvement, while an apparent change (832.7) was observed with the addition of 5.0 wt% WO3. The bending strength of the ferrite was optimized at 75.7 MPa with 2.0 wt% SnO2 and at 90.5 MPa with 3.5 wt% ZrO2, while that of the ferrite sintered with WO3 added dropped gradually from 62.0 to 47.7 MPa as the amount of WO3 was increased from 0 to 5.0 wt% due to the non-uniform microstructure. The pure Ni0.5Cu0.3Zn0.2Fe2O4 ceramic sintered at 1075 °C had an initial permeability of 356.9 and a quality factor of 71.2. The addition of ZrO2 led to a significant increase in the initial permeability (588.4 at 5.0 wt% ZrO2), but a slight decline in the quality factor (56.6 at 5.0 wt% ZrO2).

  6. Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

    NASA Astrophysics Data System (ADS)

    Ros, Rosa M.

    2009-12-01

    The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

  7. Effect of phosphorus additions on the sintering and transport properties of proton conducting BaZr{sub 0.85}Y{sub 0.15}O{sub 3-{delta}}

    SciTech Connect

    Soares, H.S.; Zhang, X.; Antunes, I.; Frade, J.R.; Mather, G.C.; Fagg, D.P.

    2012-07-15

    The influence of phosphorous additions on the sintering and electrical transport properties of the proton-conducting perovskite BaZr{sub 0.85}Y{sub 0.15}O{sub 3-{delta}} (BZY) has been studied with a view to the use of phosphates as typical dispersants for the formation of stabilised solid suspensions or as possible sintering aids. P{sub 2}O{sub 5} additions, (1-x)BZY{center_dot}xP{sub 2}O{sub 5}, monotonously promote densification in the intermediate compositional range 0.04{<=}x{<=}0.08. Nonetheless, BZY reacts with phosphorous forming the phase Ba{sub 3}(PO{sub 4}){sub 2} at temperatures as low as 600 Degree-Sign C. The associated loss of Ba from the perovskite, leads to a decrease in the perovskite lattice parameter, the formation of yttria-based impurity phases and impaired grain growth. Such reaction has an extremely detrimental effect on bulk and grain boundary conductivities. It is, therefore, vital that the current results are taken into account by the protonics community when attempting to prepare the stabilised solid suspensions of BZY nanopowders required for thin ceramic applications. Alternative dispersants to phosphate esters must be found. - Graphical Abstract: Sintering experiments performed at 1500 Degree-Sign C for 5 h and at 1400 Degree-Sign C for 24 h of (1-x)BaZr{sub 0.85}Y{sub 0.15}O{sub 3-{delta}}{center_dot}xP{sub 2}O{sub 5} in the range x=0-0.10. Highlights: Black-Right-Pointing-Pointer P{sub 2}O{sub 5} additions, (1-x)BZY{center_dot}xP{sub 2}O{sub 5}, promote densification in the intermediate compositional range 0.04{<=}x{<=}0.08. Black-Right-Pointing-Pointer BZY reacts with phosphorous forming the phase Ba{sub 3}(PO{sub 4}){sub 2} at temperatures as low as 600 Degree-Sign C. Black-Right-Pointing-Pointer Detrimental effects on bulk and grain boundary conductivities are shown. Black-Right-Pointing-Pointer Alternative dispersants to phosphate esters must be found.

  8. Observations on the Influence of Secondary Me Oxides Additives (Me=Si,Al, Mg) on the Microstructural Evolution and Mechanical Behavior of Silicon Nitride Ceramics Containing RE2O3 (RE=La, Gd, Lu)

    SciTech Connect

    Becher, Paul F; Averill, Frank; Lin, Hua-Tay; Waters, Shirley B; Shibata, Naoya; Painter, Gayle S; van Benthem, Klaus

    2010-01-01

    The evolution of β Si3N4 microstructures is influenced by the adsorption of rare earth elements at grain surfaces and by the viscosity of the intergranular phases. Theoretical and STEM studies show that the RE atoms exhibit different tendencies to segregate from the liquid phase to grain surfaces and different binding strengths at these surfaces. When combined with MgO (or Al2O3) secondary additions, the rare earth additives are combined in low viscosity intergranular phases during densification and the α to β phase transformation and microstructural evolution are dominated by the RE adsorption behavior. On the other hand, a much higher viscosity intergranular phase forms when the RE2O3 are combined with SiO2. While the rare earth adsorption behavior remains the same, the phase transformation and microstructure are now dominated by Si3N4 solubility and transport in the high liquid phase. By understanding these additive effects, one can develop reinforced microstructures leading silicon nitride ceramics with greatly improved mechanical behavior.

  9. Effects of Lithium Oxide Addition on Sintering Behavior and Electrical Conductivity of Ce0.8Gd0.2O1.9 Ceramics Prepared by Commercial Powders.

    PubMed

    Seo, Seung-Woo; Park, Min-Woo; Lee, Joo-Sin

    2016-05-01

    The densification behavior and electrical conductivity of Ce0.8Gd0.2O1.9 ceramics with lithium oxide concentrations ranging from 0 to 7 mol% were investigated. The sintered density was found to increase with increasing Li2O content up to 2 mol% and then to decrease somewhat upon further Li20 addition. Dense Ce0.8Gd0.2O1.9 ceramics with 97% of the theoretical density could be obtained by sintering the milled mixture with 2 mol% Li2O addition at 1250 degrees C for 5 h. The conductivity of the 2 mol% Li2O-added specimen showed a maximum value of 4.99 x 10(-3) Ω(-1) x cm(-1) at 700 degrees C. Pure Ce0.8Gd0.2O1.9 ceramics needed to be sintered at 1550 degrees C in order to obtain an equivalent theoretical density and conductivity. The addition of Li2O was found to promote the sintering properties and electrical conductivities of Gd2O3-doped CeO2.

  10. Effects of Lithium Oxide Addition on Sintering Behavior and Electrical Conductivity of Ce0.8Gd0.2O1.9 Ceramics Prepared by Commercial Powders.

    PubMed

    Seo, Seung-Woo; Park, Min-Woo; Lee, Joo-Sin

    2016-05-01

    The densification behavior and electrical conductivity of Ce0.8Gd0.2O1.9 ceramics with lithium oxide concentrations ranging from 0 to 7 mol% were investigated. The sintered density was found to increase with increasing Li2O content up to 2 mol% and then to decrease somewhat upon further Li20 addition. Dense Ce0.8Gd0.2O1.9 ceramics with 97% of the theoretical density could be obtained by sintering the milled mixture with 2 mol% Li2O addition at 1250 degrees C for 5 h. The conductivity of the 2 mol% Li2O-added specimen showed a maximum value of 4.99 x 10(-3) Ω(-1) x cm(-1) at 700 degrees C. Pure Ce0.8Gd0.2O1.9 ceramics needed to be sintered at 1550 degrees C in order to obtain an equivalent theoretical density and conductivity. The addition of Li2O was found to promote the sintering properties and electrical conductivities of Gd2O3-doped CeO2. PMID:27483925

  11. 10 CFR 810.14 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Additional information. 810.14 Section 810.14 Energy DEPARTMENT OF ENERGY ASSISTANCE TO FOREIGN ATOMIC ENERGY ACTIVITIES § 810.14 Additional information. The Department of Energy may at any time require a person engaging in any generally or specifically...

  12. 10 CFR 810.14 - Additional information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Additional information. 810.14 Section 810.14 Energy DEPARTMENT OF ENERGY ASSISTANCE TO FOREIGN ATOMIC ENERGY ACTIVITIES § 810.14 Additional information. The Department of Energy may at any time require a person engaging in any generally or specifically...

  13. 10 CFR 810.14 - Additional information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Additional information. 810.14 Section 810.14 Energy DEPARTMENT OF ENERGY ASSISTANCE TO FOREIGN ATOMIC ENERGY ACTIVITIES § 810.14 Additional information. The Department of Energy may at any time require a person engaging in any generally or specifically...

  14. 10 CFR 810.14 - Additional information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Additional information. 810.14 Section 810.14 Energy DEPARTMENT OF ENERGY ASSISTANCE TO FOREIGN ATOMIC ENERGY ACTIVITIES § 810.14 Additional information. The Department of Energy may at any time require a person engaging in any generally or specifically...

  15. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 67.22 Section 67.22 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING... Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  16. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 67.22 Section 67.22 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING... Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  17. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 67.22 Section 67.22 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING... Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  18. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 67.22 Section 67.22 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING... Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  19. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 67.22 Section 67.22 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING... Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  20. 77 FR 56813 - Procurement List, Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-14

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List, Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add a product and services to the Procurement List that will...

  1. 77 FR 49784 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-17

    ... FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee... Procurement List. SUMMARY: The Committee is proposing to add services to the Procurement List that will be... connection with the services proposed for addition to the Procurement List. Comments on this...

  2. 77 FR 62220 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY: This action adds products and services to the Procurement List that will be furnished by nonprofit...

  3. 28 CFR 80.7 - Additional information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Additional information. 80.7 Section 80.7... § 80.7 Additional information. If an issuer's or domestic concern's submission does not contain all of the information required by § 80.6, the Department of Justice may request whatever...

  4. 25 CFR 214.5 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Additional information. 214.5 Section 214.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.5 Additional information. The officer in...

  5. 25 CFR 214.5 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Additional information. 214.5 Section 214.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.5 Additional information. The officer in charge may, at...

  6. 25 CFR 214.5 - Additional information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Additional information. 214.5 Section 214.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.5 Additional information. The officer in...

  7. 25 CFR 214.5 - Additional information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Additional information. 214.5 Section 214.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.5 Additional information. The officer in...

  8. 25 CFR 214.5 - Additional information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Additional information. 214.5 Section 214.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.5 Additional information. The officer in...

  9. 7 CFR 958.90 - Additional parties.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Additional parties. 958.90 Section 958.90 Agriculture... Additional parties. After the effective date hereof, any handler may become a party to this agreement if a... contracting party at the time such counterpart is delivered to the Secretary, and the benefits,...

  10. 7 CFR 958.90 - Additional parties.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Additional parties. 958.90 Section 958.90 Agriculture... Additional parties. After the effective date hereof, any handler may become a party to this agreement if a... contracting party at the time such counterpart is delivered to the Secretary, and the benefits,...

  11. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND... Calves § 412.47 Additional measures. (a) Each CAFO subject to this subpart must implement...

  12. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND... Calves § 412.47 Additional measures. (a) Each CAFO subject to this subpart must implement...

  13. 75 FR 51444 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-20

    ... . SUPPLEMENTARY INFORMATION: Additions On 6/4/2010 (75 FR 31768-31769); 6/11/2010 (75 FR 33270-33271); 6/ 18/2010 (75 FR 34701-34702); and 6/25/2010 (75 FR 36363-36371), the Committee for Purchase From People Who Are... factors considered for this certification were: 1. The action will not result in any additional...

  14. 34 CFR 75.231 - Additional information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS How Grants Are Made Procedures to Make A Grant § 75.231 Additional information. After selecting an application for funding, the Secretary may require the applicant to submit additional information. (Authority: 20 U.S.C. 1221e-3 and 3474)...

  15. 34 CFR 75.231 - Additional information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS How Grants Are Made Procedures to Make A Grant § 75.231 Additional information. After selecting an application for funding, the Secretary may require the applicant to submit additional information. (Authority: 20 U.S.C. 1221e-3 and 3474)...

  16. 34 CFR 75.231 - Additional information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS How Grants Are Made Procedures to Make A Grant § 75.231 Additional information. After selecting an application for funding, the Secretary may require the applicant to submit additional information. (Authority: 20 U.S.C. 1221e-3 and 3474)...

  17. 34 CFR 75.231 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS How Grants Are Made Procedures to Make A Grant § 75.231 Additional information. After selecting an application for funding, the Secretary may require the applicant to submit additional information. (Authority: 20 U.S.C. 1221e-3 and 3474)...

  18. 34 CFR 75.231 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS How Grants Are Made Procedures to Make A Grant § 75.231 Additional information. After selecting an application for funding, the Secretary may require the applicant to submit additional information. (Authority: 20 U.S.C. 1221e-3 and 3474)...

  19. 7 CFR 1735.18 - Additional equity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 11 2011-01-01 2011-01-01 false Additional equity. 1735.18 Section 1735.18 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF... Basic Policies § 1735.18 Additional equity. If determined by the Administrator to be necessary for...

  20. 7 CFR 1735.18 - Additional equity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Additional equity. 1735.18 Section 1735.18 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF... Basic Policies § 1735.18 Additional equity. If determined by the Administrator to be necessary for...

  1. 28 CFR 80.7 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Additional information. 80.7 Section 80.7... § 80.7 Additional information. If an issuer's or domestic concern's submission does not contain all of the information required by § 80.6, the Department of Justice may request whatever...

  2. 76 FR 82279 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    .../2011(76 FR 66913-66914), the Committee for Purchase From People Who Are Blind or Severely Disabled... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  3. 76 FR 29210 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-20

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List... furnished by nonprofit agencies employing persons who are blind or have other severe disabilities....

  4. 78 FR 14999 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... 2378); and 1/18/2013 (78 FR 4133-4134), the Committee for Purchase From People Who Are Blind or... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  5. 77 FR 77038 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and a service to the Procurement List that will...

  6. 76 FR 34064 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-10

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List... nonprofit agencies employing persons who are blind or have other severe disabilities. Comments Must...

  7. 77 FR 29596 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the... that will be furnished by nonprofit agencies employing persons who are blind or have other...

  8. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  9. Working Memory and Children's Mental Addition.

    ERIC Educational Resources Information Center

    Adams, John W.; Hitch, Graham J.

    1997-01-01

    Two experiments investigated extent to which English- and German-speaking childrens' mental arithmetic was constrained by working memory. Found higher mental addition spans when numbers were visible throughout calculation than when not. Variation in addition span with age and arithmetical operation difficulty approximated to a linear function of…

  10. 15 CFR 292.6 - Additional requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Additional requirements. 292.6 Section 292.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE... PARTNERSHIP; INFRASTRUCTURE DEVELOPMENT PROJECTS § 292.6 Additional requirements. Federal policies...

  11. 15 CFR 292.6 - Additional requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Additional requirements. 292.6 Section 292.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE... PARTNERSHIP; INFRASTRUCTURE DEVELOPMENT PROJECTS § 292.6 Additional requirements. Federal policies...

  12. 15 CFR 292.6 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Additional requirements. 292.6 Section 292.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE... PARTNERSHIP; INFRASTRUCTURE DEVELOPMENT PROJECTS § 292.6 Additional requirements. Federal policies...

  13. 15 CFR 292.6 - Additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Additional requirements. 292.6 Section 292.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade NATIONAL INSTITUTE... PARTNERSHIP; INFRASTRUCTURE DEVELOPMENT PROJECTS § 292.6 Additional requirements. Federal policies...

  14. 75 FR 36362 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-25

    ... . SUPPLEMENTARY INFORMATION: Additions On 1/22/2010 (75 FR 3714); 3/19/2010 (75 FR 13263-13264); 4/9/2010 (75 FR 18164-18165); and 4/30/2010 (75 FR 22744-22745), the Committee for Purchase From People Who Are Blind or Severely Disabled published notices of proposed additions to the Procurement List. Glove, Mechanic's...

  15. 77 FR 27737 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-11

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add services to the Procurement List that will be provided...

  16. 78 FR 67129 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-08

    ... 8/23/2013 (78 FR 52512-52513), 8/30/2013 (78 FR 53734), and 9/6/ 2013 (78 FR 54871), the Committee... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  17. 75 FR 4783 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-29

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add to the Procurement List products and services to be...

  18. 77 FR 70737 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products to the Procurement List that will be furnished...

  19. 75 FR 3714 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-22

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the procurement list. SUMMARY: The Committee is proposing to add to the Procurement List a product and a service to be...

  20. 76 FR 38641 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-01

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and services to the Procurement List that will...

  1. 76 FR 41767 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add a product and services to the Procurement List that will...

  2. 76 FR 59117 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-23

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and services to the Procurement List that will...

  3. 78 FR 40727 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-08

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and a service to the Procurement List that will...

  4. 75 FR 69639 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Addition to the Procurement List. SUMMARY: The Committee is proposing to add a service to the Procurement List that will be provided by...

  5. 78 FR 52512 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-23

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add products and a service to the Procurement List that will...

  6. 76 FR 75536 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-02

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Addition to the Procurement List. SUMMARY: The Committee is proposing to add a service to the Procurement List that will be provided by...

  7. 75 FR 34701 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and services to the Procurement List that will...

  8. 77 FR 37658 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-22

    ... . SUPPLEMENTARY INFORMATION: Revision On 5/25/2012 (77 FR 31335-31336), the Committee for Purchase From People Who... addition must be received on or before June 25, 2012. Additions On 4/13/2012 (77 FR 22289-22290) and 4/20/2012 (77 FR 23665-23666), the Committee for Purchase From People Who Are Blind or Severely...

  9. 78 FR 53734 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products to the Procurement List that will be furnished by...

  10. 76 FR 26279 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-06

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add services to the Procurement List that will be provided...

  11. 77 FR 69598 - Procurement List Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-20

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed addition to the procurement list. SUMMARY: The Committee is proposing to add a service to the Procurement List that will be provided by...

  12. 76 FR 72908 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add products and a service to the Procurement List that will...

  13. 78 FR 34351 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... (78 FR 21916), the Committee for Purchase from People Who are Blind or Severely Disabled published... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase from People Who are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  14. 75 FR 2510 - Procurement List: Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-15

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List: Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to Procurement List. SUMMARY: The Committee is proposing to add to the Procurement List services to be provided by...

  15. 77 FR 27736 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-11

    ... . SUPPLEMENTARY INFORMATION: Additions On 9/23/2011 (76 FR 59117-59118); 3/9/2012 (77 FR 14352-14353); and 3/16/2012 (77 FR 15736), the Committee for Purchase From People Who Are Blind or Severely Disabled published... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Additions AGENCY: Committee for Purchase...

  16. 78 FR 40727 - Procurement List Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-08

    ... (78 FR 25970-25971), the Committee for Purchase From People Who Are Blind or Severely Disabled... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  17. 75 FR 60739 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-01

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the procurement list. SUMMARY: The Committee is proposing to add services to the Procurement List that will be provided...

  18. 76 FR 14943 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products to the Procurement List that will be furnished by...

  19. 75 FR 62370 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-08

    ... PEOPLE WHO AREBLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products and services to the Procurement List that will...

  20. 78 FR 50040 - Procurement List, Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List, Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add services to the Procurement List that will be provided...

  1. 77 FR 41377 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Addition to the Procurement List. SUMMARY: The Committee is proposing to add a service to the Procurement List that will be furnished by...

  2. 77 FR 37659 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-22

    ... interested persons an opportunity to submit comments on the proposed actions. Revision On 5/25/2012 (77 FR... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who are Blind or Severely Disabled. ACTION: Proposed additions to the procurement...

  3. 77 FR 67343 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add a product and services to the Procurement List that will...

  4. 78 FR 7412 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add products to the Procurement List that will be furnished by...

  5. 78 FR 32632 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... 4/5/2013 (78 FR 20622-20623), the Committee for Purchase From People Who Are Blind or Severely... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Addition AGENCY: Committee for Purchase from People Who are Blind or Severely Disabled. ACTION: Addition to the Procurement List. SUMMARY: This...

  6. 76 FR 47565 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the Procurement List. SUMMARY: The Committee is proposing to add services to the Procurement List that will be provided...

  7. 76 FR 32146 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-03

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add products and a service to the Procurement List that will...

  8. The Additive Coloration of Alkali Halides

    ERIC Educational Resources Information Center

    Jirgal, G. H.; and others

    1969-01-01

    Describes the construction and use of an inexpensive, vacuum furnace designed to produce F-centers in alkali halide crystals by additive coloration. The method described avoids corrosion or contamination during the coloration process. Examination of the resultant crystals is discussed and several experiments using additively colored crystals are…

  9. 42 CFR 66.115 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 66.115 Section 66.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.115 Additional conditions. The Secretary may...

  10. 42 CFR 66.115 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 66.115 Section 66.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.115 Additional conditions. The Secretary may...

  11. 42 CFR 66.115 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 66.115 Section 66.115 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.115 Additional conditions. The Secretary may...

  12. Contexts for Column Addition and Subtraction

    ERIC Educational Resources Information Center

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by designing…

  13. 12 CFR 619.9010 - Additional security.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Additional security. 619.9010 Section 619.9010 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9010 Additional security. Supplementary collateral to the primary security taken in connection with the loan....

  14. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  15. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  16. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  17. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  18. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  19. DECISION-MAKING, SCIENCE AND GASOLINE ADDITIVES

    EPA Science Inventory


    Methyl-tert butyl ether (MTBE) has been used as a gasoline additive to serve two major purposes. The first use was as an octane-enhancer to replace organic lead, beginning in 1979. The second use, which began about 1992, was as an oxygenated additive to meet requirements ...

  20. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  1. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  2. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  3. 31 CFR 354.10 - Additional provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING BOOK-ENTRY SECURITIES OF THE STUDENT LOAN MARKETING ASSOCIATION (SALLIE MAE) § 354.10 Additional provisions. (a) Additional... Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by...

  4. 76 FR 40341 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-08

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY: This action adds products and services to the Procurement List that will be furnished by nonprofit...

  5. 78 FR 23542 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-19

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY: This action adds products and services to the Procurement List that will be furnished by nonprofit...

  6. 77 FR 77037 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY: This action adds products and services to the Procurement List that will be furnished by nonprofit...

  7. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  8. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  9. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  10. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  11. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  12. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  13. 75 FR 14575 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-26

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List. SUMMARY: The Committee is proposing to add to the Procurement List products and a service to be...

  14. 78 FR 22209 - Additional Synthetic Drug Testing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... COMMISSION 10 CFR Part 26 Additional Synthetic Drug Testing AGENCY: Nuclear Regulatory Commission. ACTION... NRC amend its Fitness for Duty program regulations to amend drug testing requirements to test for additional synthetic drugs currently not included in the regulations. The NRC determined that the...

  15. Developing Multiplicative Thinking from Additive Reasoning

    ERIC Educational Resources Information Center

    Tobias, Jennifer M.; Andreasen, Janet B.

    2013-01-01

    As students progress through elementary school, they encounter mathematics concepts that shift from additive to multiplicative situations (NCTM 2000). When they encounter fraction problems that require multiplicative thinking, they tend to incorrectly extend additive properties from whole numbers (Post et al. 1985). As a result, topics such as …

  16. French and English Together: An "Additive" Experience

    ERIC Educational Resources Information Center

    Wiltshire, Jessica; Harbon, Lesley

    2010-01-01

    This paper examines the nature of the "additive" experience of a bilingual French-English curriculum at Killarney Heights Public School in New South Wales. Predictably, the well-supported "additive" nature of the languages program model elicited positive reactions regarding educational success. The paper also explores issues for administration,…

  17. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  18. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  19. 75 FR 52724 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-27

    ... . SUPPLEMENTARY INFORMATION: Additions On 10/23/2009 (74 FR 54783-54784); 6/18/2010 (75 FR 34701-34702); 6/25/2010 (75 FR 36363-36371); and 7/9/2010 (75 FR 39497-39499), the Committee for Purchase From People Who Are... additional reporting, recordkeeping or other compliance requirements for small entities other than the...

  20. 30 CFR 256.53 - Additional bonds.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Additional bonds. 256.53 Section 256.53 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE LEASING OF SULPHUR OR OIL AND GAS IN THE OUTER CONTINENTAL SHELF Bonding § 256.53 Additional bonds. (a) This paragraph explains...

  1. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The... health and to minimize danger to life or property....

  2. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  3. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  4. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Introduction § 308.502 Additional insurance. The assured may place increased value...

  5. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  6. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  7. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  8. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  9. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  10. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  11. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  12. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  13. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  14. 75 FR 81235 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... INFORMATION: Addition On 10/1/2010 (75 FR 60739-60740), the Committee for Purchase From People Who Are Blind... Attendant, Pease Air National Guard Base, Newington, NH. Comments on the proposed addition were received... added to the Procurement List: Service Service Type/Location: Food Service Attendant, Pease Air...

  15. 10 CFR 81.50 - Additional licenses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Additional licenses. 81.50 Section 81.50 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) STANDARD SPECIFICATIONS FOR THE GRANTING OF PATENT LICENSES Nrc-Owned Inventions-Patents and Applications § 81.50 Additional licenses. Subject to any outstanding licenses,...

  16. Asthma and anaphylactoid reactions to food additives.

    PubMed Central

    Tarlo, S. M.; Sussman, G. L.

    1993-01-01

    Presumed allergic reactions to hidden food additives are both controversial and important. Clinical manifestations include asthma, urticaria, angioedema, and anaphylactic-anaphylactoid events. Most adverse reactions are caused by just a few additives, such as sulfites and monosodium glutamate. Diagnosis is suspected from the history and confirmed by specific challenge. The treatment is specific avoidance. PMID:8499792

  17. 12 CFR 619.9010 - Additional security.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Additional security. 619.9010 Section 619.9010 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9010 Additional security. Supplementary collateral to the primary security taken in connection with the loan....

  18. Straightness error evaluation of additional constraints

    NASA Astrophysics Data System (ADS)

    Pei, Ling; Wang, Shenghuai; Liu, Yong

    2011-05-01

    A new generation of Dimensional and Geometrical Product Specifications (GPS) and Verification standard system is based on both the Mathematical structure and the Metrology. To determine the eligibility of the product should be adapt to modern digital measuring instruments. But in mathematizating measurement when the geometric tolerance specifications has additional constraints requirement, such as straightness with an additional constraint, required to qualify the additional form requirements of the feature within the tolerance zone. Knowing how to close the geometrical specification to the functional specification will result in the correctness of measurement results. Adopting the methodology to evaluate by analyzing various forms including the ideal features and the extracted features and their combinations in an additional form constraint of the straightness in tolerance zone had been found correctly acceptance decision for products. The results show that different combinations of the various forms had affected acceptance on the product qualification and the appropriate forms matching can meet the additional form requirements for product features.

  19. Straightness error evaluation of additional constraints

    NASA Astrophysics Data System (ADS)

    Pei, Ling; Wang, Shenghuai; Liu, Yong

    2010-12-01

    A new generation of Dimensional and Geometrical Product Specifications (GPS) and Verification standard system is based on both the Mathematical structure and the Metrology. To determine the eligibility of the product should be adapt to modern digital measuring instruments. But in mathematizating measurement when the geometric tolerance specifications has additional constraints requirement, such as straightness with an additional constraint, required to qualify the additional form requirements of the feature within the tolerance zone. Knowing how to close the geometrical specification to the functional specification will result in the correctness of measurement results. Adopting the methodology to evaluate by analyzing various forms including the ideal features and the extracted features and their combinations in an additional form constraint of the straightness in tolerance zone had been found correctly acceptance decision for products. The results show that different combinations of the various forms had affected acceptance on the product qualification and the appropriate forms matching can meet the additional form requirements for product features.

  20. Additional waves in the graphene layered medium.

    PubMed

    Chern, Ruey-Lin; Han, Dezhuan; Zhang, Z Q; Chan, C T

    2014-12-29

    We investigate the features of additional waves that arise in the graphene layered medium, within the framework of nonlocal effective medium model. The additional wave is manifest on the biquadratic dispersion relation of the medium and represents as a distinctive nonlocal character at long wavelength. In particular, the reflection and transmission coefficients for the nonlocal medium are underdetermined by Maxwell's boundary conditions. An additional boundary condition based on modal expansions is proposed to derive the generalized Fresnel equations, based on which the additional wave in the graphene layered medium is determined. The additional wave tends to be significant near the effective plasma frequency, near which the graphene plasmons are excited inside the medium. PMID:25607138

  1. Photoactive devices including porphyrinoids with coordinating additives

    DOEpatents

    Forrest, Stephen R; Zimmerman, Jeramy; Yu, Eric K; Thompson, Mark E; Trinh, Cong; Whited, Matthew; Diev, Vlacheslav

    2015-05-12

    Coordinating additives are included in porphyrinoid-based materials to promote intermolecular organization and improve one or more photoelectric characteristics of the materials. The coordinating additives are selected from fullerene compounds and organic compounds having free electron pairs. Combinations of different coordinating additives can be used to tailor the characteristic properties of such porphyrinoid-based materials, including porphyrin oligomers. Bidentate ligands are one type of coordinating additive that can form coordination bonds with a central metal ion of two different porphyrinoid compounds to promote porphyrinoid alignment and/or pi-stacking. The coordinating additives can shift the absorption spectrum of a photoactive material toward higher wavelengths, increase the external quantum efficiency of the material, or both.

  2. Evaluation of certain food additives and contaminants.

    PubMed

    2002-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) and tolerable intakes, respectively, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives (including flavouring agents) and contaminants, assessments of intake, and the establishment and revision of specifications for food additives. A summary follows of the Committee's evaluations of toxicological and intake data on various specific food additives (diacetyltartaric and fatty acid esters of glycerol, quillaia extracts, invertase from Saccharomyces cerevisiae, beta-carotene from Blakeslea trispora, curcumin, phosphates, diphosphates and polyphosphates, hydrogenated poly-1-decene, natamycin, D-tagatose, carrageenan, processed Eucheuma seaweed, curdlan, acetylated oxidized starch, alpha-cyclodextrin and sodium sulfate), flavouring agents and contaminants (3-chloro-1,2-propanediol, 1,3-dichloro-2-propanol, and a large number of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and tolerable intakes of the contaminants considered, changes in the status of specifications of these food additives and specific flavouring agents, and further information required or desired. PMID:12564044

  3. Anaerobic sludge digestion with a biocatalytic additive

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

  4. Active mineral additives of sapropel ashes

    NASA Astrophysics Data System (ADS)

    Khomich, V. A.; Danilina, E. V.; Krivonos, O. I.; Plaksin, G. V.

    2015-01-01

    The goal of the presented research is to establish a scientific rational for the possibility of sapropel ashes usage as an active mineral additive. The research included the study of producing active mineral additives from sapropels by their thermal treatment at 850900 °C and afterpowdering, the investigation of the properties of paste matrix with an ash additive, and the study of the ash influence on the cement bonding agent. Thermogravimetric analysis and X-ray investigations allowed us to establish that while burning, organic substances are removed, clay minerals are dehydrated and their structure is broken. Sapropel ashes chemical composition was determined. An amorphous ash constituent is mainly formed from silica of the mineral sapropel part and alumosilicagels resulted from clay minerals decomposition. Properties of PC 400 and PC 500A0 sparopel ash additives were studied. Adding ashes containing Glenium plasticizer to the cement increases paste matrix strength and considerably reduces its water absorption. X-ray phase analysis data shows changes in the phase composition of the paste matrix with an ash additive. Ash additives produce a pozzolanic effect on the cement bonding agent. Besides, an ash additive due to the alumosilicagels content causes transformation from unstable calcium aluminate forms to the stable ones.

  5. Evaluation of certain food additives and contaminants.

    PubMed

    2001-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) and tolerable intakes, respectively, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives and contaminants (including flavouring agents), and the establishment and revision of specifications. A summary follows of the Committee's evaluations of toxicological data on various specific food additives (furfural, paprika oleoresin, caramel colour II, cochineal extract, carmines, aspartame-acesulfame salt, D-tagatose, benzoyl peroxide, nitrous oxide, stearyl tartrate and trehalose), flavouring agents and contaminants (cadmium and tin), and of intake data on calcium from calcium salts of food additives. Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and tolerable intakes of the contaminants considered, changes in the status of specifications of these food additives and specific flavouring agents, and further information required or desired.

  6. Evaluating additives and impurities in zinc electrowinning

    NASA Astrophysics Data System (ADS)

    Gonzalez-Dominguez, J. A.; Lew, R. W.

    1995-01-01

    The zinc electrowinning (EW) process is very sensitive to the presence of impurities. There is only one EW plant in the world that we know of that operates at moderate current efficiency and deposition times without using any additives. All the others must use them continuously. Additives allow zinc EW to occur at high current efficiencies while suppressing excessive acid mist formation. The study of the electrochemical effects of additives in zinc EW is not straightforward. This article presents a review of the experimental techniques currently used at Cominco Research: Cyclic voltammetry, Hull cells, laboratory and mini-cell electrowinning techniques are all described and their relationship to the industrial operation is discussed.

  7. The grays of medical device color additives.

    PubMed

    Seidman, Brenda

    2014-01-01

    The United States' medical device color additive regulations are unknown to some, and confusing to many. This article reviews statutory language on color additives in the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended, including the Delaney Clause on carcinogenicity; color additive regulatory language as it relates to medical devices in Title 21 of the Code of Federal Regulations (C.F.R.), Parts 70-82; reports on the Food and Drug Administration's (FDA's) likely current and historical practices in dealing with color additives in medical devices; and speculates on what may have given rise to decades of seemingly ad hoc color additives practices, which may now be difficult to reconstruct and satisfactorily modify. Also addressed is the Center for Devices and Radiological Health's (CDRH's) recent publicly-vetted approach to color additives in Section 7 of its April 2013 draft guidance, Use of International Standard ISO-10993, "Biological Evaluation of Medical Devices Part 1: Evaluation and Testing," which the author concludes is a change in the right direction, but which, at least in its current draft form, is not a fix to the CDRH's color additives dilemma. Lastly, the article suggests what the CDRH might consider in further developing a new approach to color additives. Such an approach would treat color additives as if they were any other potentially toxic group of chemicals, and could be fashioned in such a way that the CDRH could still satisfy the broad aspects of Congressional color additives mandates, and.yet be consistent with ISO 10993. In doing this, the CDRH would need to recommend a more directed use of its Quality System Regulation, 21 C.F.R. Part 820, for material and vendor qualification and validation in general; approach Congress for needed statutory changes; or make administrative changes. In order for any approach to be successful, whether it is a new twist on past practices, or an entirely new path forward, the FDA must, to the best of its

  8. Food additives--an unending controversy.

    PubMed

    Fennema, O R

    1987-07-01

    The use of food additives originated in ancient times but did not engender controversy until the early 1800s, when intentional food adulteration became appallingly common in some countries. Problems with intentional food adulteration continued until about 1920, when regulatory pressures and effective methods of food analysis reduced the frequency and seriousness of food adulteration to acceptable levels in the United States. Since 1920 the use of legally sanctioned food additives has become common. However, for the last several decades the regulation of food additives has been a matter of controversy. Explanations for this controversy, which is likely to continue, are not difficult to identify and are discussed in the text.

  9. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE (Eff. Jan. 10, 2011) Content Requirements... notices, the CPSC shall include in the Database any additional information it determines to be in...

  10. 27 CFR 5.33 - Additional requirements.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... English, and for products bottled for consumption within Puerto Rico the required information may be... cannot be removed without thorough application of water or other solvents. (f) Additional information...

  11. 27 CFR 5.33 - Additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... English, and for products bottled for consumption within Puerto Rico the required information may be... cannot be removed without thorough application of water or other solvents. (f) Additional information...

  12. 27 CFR 5.33 - Additional requirements.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... English, and for products bottled for consumption within Puerto Rico the required information may be... cannot be removed without thorough application of water or other solvents. (f) Additional information...

  13. 27 CFR 5.33 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... English, and for products bottled for consumption within Puerto Rico the required information may be... cannot be removed without thorough application of water or other solvents. (f) Additional information...

  14. 77 FR 23665 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-20

    ... . SUPPLEMENTARY INFORMATION: Additions On 2/24/2012 (77 FR 11072-11073), the Committee for Purchase From People...: Lighthouse of Central Florida, Orlando, FL. Contracting Activity: Defense Logistics Agency Troop...

  15. 78 FR 5423 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ... INFORMATION: Additions On 11/27/2012 (77 FR 70737-70738), the Committee for Purchase From People Who Are Blind.... Containers. NSN: 8950-01-E62-0111--Spice, Cumin, Ground, 6/16 oz. Containers. NSN:...

  16. Revisiting Additivity Violation of Quantum Channels

    NASA Astrophysics Data System (ADS)

    Fukuda, Motohisa

    2014-12-01

    We prove additivity violation of minimum output entropy of quantum channels by straightforward application of -net argument and Lévy's lemma. The additivity conjecture was disproved initially by Hastings. Later, a proof via asymptotic geometric analysis was presented by Aubrun, Szarek and Werner, which uses Dudley's bound on Gaussian process (or Dvoretzky's theorem with Schechtman's improvement). In this paper, we develop another proof along Dvoretzky's theorem in Milman's view, showing additivity violation in broader regimes than the existing proofs. Importantly,Dvoretzky's theorem works well with norms to give strong statements, but these techniques can be extended to functions which have norm-like structures-positive homogeneity and triangle inequality. Then, a connection between Hastings' method and ours is also discussed. In addition, we make some comments on relations between regularized minimum output entropy and classical capacity of quantum channels.

  17. 77 FR 53179 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... addition to the Procurement List for production by the nonprofit agencies listed: Products NSN: 1095-01-446-4348--Knife, Combat, Drop Point, Automatic, with Sheath. NSN: 1095-01-456-4457--Knife, Combat,...

  18. 75 FR 21246 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... INFORMATION: Addition On 2/26/2010 (75 FR 8927), the Committee for Purchase From People Who Are Blind or..., Lemonade. NSN: 8955-01-E10-1650--Beverage Base, Non-nutritive Sweetened, Raspberry Ice. NPA:...

  19. 77 FR 44218 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... . SUPPLEMENTARY INFORMATION: Additions On 5/11/2012 (77 FR 27737-27738) and 6/1/2012 (77 FR 32591-32592), the...: 3895-00-NIB-0002--Asphalt Lute, Aluminum Head, Industrial Grade, 67'' Fiberglass Handle,...

  20. Effect of additives on protein aggregation.

    PubMed

    Hamada, Hiroyuki; Arakawa, Tsutomu; Shiraki, Kentaro

    2009-06-01

    This paper overviews solution additives that affect protein stability and aggregation during refolding, heating, and freezing processes. Solution additives are mainly grouped into two classes, i.e., protein denaturants and stabilizers. The former includes guanidine, urea, strong ionic detergents, and certain chaotropic salts; the latter includes certain amino acids, sugars, polyhydric alcohols, osmolytes, and kosmotropic salts. However, there are solution additives that are not unambiguously placed into these two classes, including arginine, certain divalent cation salts (e.g., MgCl(2)) and certain polyhydric alcohols (e.g., ethylene glycol). Certain non-ionic or non-detergent surfactants, ionic liquids, amino acid derivatives, polyamines, and certain amphiphilic polymers may belong to this class. They have marginal effects on protein structure and stability, but are able to disrupt protein interactions. Information on additives that do not catalyze chemical reactions nor affect protein functions helps us to design protein solutions for increased stability or reduced aggregation. PMID:19519415

  1. 75 FR 28590 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... INFORMATION: Additions On 3/26/2010 (75 FR 14575-14576), the Committee for Purchase From People Who Are Blind... NATICK, Natick, MA. Tape, Insulation, Electrical NSN: 5970-00-240-0617. NSN: 5970-00-685-9059. NSN:...

  2. 75 FR 52723 - Procurement List Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-27

    ... INFORMATION: Addition On 7/9/2010 (75 FR 39497-39499), the Committee for Purchase From People Who Are Blind or..., Federal Aviation Administration, William J. Hughes Technical Center (Center- wide), Atlantic...

  3. 76 FR 65501 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-21

    ... INFORMATION: Additions On 8/19/2011 (76 FR 51955-51956) and 8/26/2011 (76 FR 53419-53420), the Committee for..., FA8751 AFRL RIKO, Rome, NY. Patricia Briscoe, Deputy Director, Business Operations, Pricing...

  4. Overview of Food Ingredients, Additives and Colors

    MedlinePlus

    ... additives? Q. How are ingredients listed on a product label? A . Food manufacturers are required to list all ... in the food on the label. On a product label, the ingredients are listed in order of predominance, ...

  5. 77 FR 7137 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ... . SUPPLEMENTARY INFORMATION: Additions On 11/28/2011 (76 FR 72908-72909) and 12/9/2011 (76 FR 76952- 76953), the... following products and service are added to the Procurement List: Products Blade, Surgical Knife,...

  6. 75 FR 18163 - Procurement List Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ...: Addition On 2/12/2010 (75 FR 6869-6870), the Committee for Purchase From People Who Are Blind or Severely...-01-503-2033--CD/DVD Sleeves, Clear. NPA: North Central Sight Services, Inc., Williamsport,...

  7. Moon Phase & Libration 2013: Additional Graphics

    NASA Video Gallery

    This visualization shows the phase and libration of the Moon throughout the year 2013, at hourly intervals. Each frame represents one hour. In addition, this version of the visualization shows addi...

  8. 78 FR 17641 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-22

    ...: Additions On 12/21/2012 (77 FR 75616) and 1/25/2013 (78 FR 5423), the Committee for Purchase From People Who...: MR 1057--Butterfly Mop, Hybrid Sponge NSN: MR 1058--Refill, Hybrid Sponge Head, Blue NPA:...

  9. 76 FR 55882 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-09

    ... INFORMATION: Additions On 6/17/2011 (76 FR 35415-35417), the Committee for Purchase From People Who Are Blind...--Detergent, Laundry, Biobased with Bleach, Powdered/7930-01-490-7301 NPA: Association for the Blind...

  10. 75 FR 31769 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... . SUPPLEMENTARY INFORMATION: Additions On 4/9/2010 (75 FR 18164-18165), the Committee for Purchase From People Who... Force, FA3020 82 CONS LGC, Sheppard AFB, TX. Barry S. Lineback, Director, Business Operations....

  11. 78 FR 4133 - Procurement List; Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-18

    ... . SUPPLEMENTARY INFORMATION: Addition On 11/9/2012 (77 FR 67343-67344), the Committee for Purchase From People Who...: Lakeview Center, Inc., Pensacola, FL. Contracting Activity: Dept of the Air Force, FA5004 354 CONS...

  12. 75 FR 75461 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-03

    ... . SUPPLEMENTARY INFORMATION: Additions On 10/8/2010 (75 FR 62370), the Committee for Purchase From People Who Are... Center, Inc., Pensacola, FL. Contracting Activity: Dept of the Air Force, FA2823 96 CONS MSC, Eglin...

  13. Caustic addition system operability test procedure

    SciTech Connect

    Parazin, R.E.

    1994-11-01

    This test procedure provides instructions for performing operational testing of the major components of the 241-AN-107 Caustic Addition System by WHC and Kaiser personnel at the Rotating Equipment Shop run-in pit (Bldg. 272E).

  14. 77 FR 41377 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... . SUPPLEMENTARY INFORMATION: Additions On 5/11/2012 (77 FR 27737-27738) and 5/18/2012 (77 FR 29596), the Committee..., Blue, 4 Piece. MR 1168--Carrier, Cake and Cupcake, Collapsible. NPA: Industries for the Blind,...

  15. 76 FR 80345 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... INFORMATION: Additions On 10/14/2011 (76 FR 63905-63906) and 10/28/2011 (76 FR 66913- 66914), the Committee... Printing, (Offsite: 880 Mustang Dr., Grapevine, TX), 9000 Blue Mound Road, Fort Worth, TX. NPA:...

  16. 40 CFR 79.31 - Additives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... produced or sold for use in motor vehicle gasoline and/or motor vehicle diesel fuel are hereby designated... additive on all emissions; (5) Toxicity and any other public health or welfare effects of the...

  17. 40 CFR 79.31 - Additives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... produced or sold for use in motor vehicle gasoline and/or motor vehicle diesel fuel are hereby designated... additive on all emissions; (5) Toxicity and any other public health or welfare effects of the...

  18. 40 CFR 79.31 - Additives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... produced or sold for use in motor vehicle gasoline and/or motor vehicle diesel fuel are hereby designated... additive on all emissions; (5) Toxicity and any other public health or welfare effects of the...

  19. 40 CFR 79.31 - Additives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... produced or sold for use in motor vehicle gasoline and/or motor vehicle diesel fuel are hereby designated... additive on all emissions; (5) Toxicity and any other public health or welfare effects of the...

  20. 40 CFR 79.31 - Additives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... produced or sold for use in motor vehicle gasoline and/or motor vehicle diesel fuel are hereby designated... additive on all emissions; (5) Toxicity and any other public health or welfare effects of the...