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Sample records for synthetic sodium aluminosilicate

  1. 21 CFR 182.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium aluminosilicate. 182.2727 Section 182.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  2. 21 CFR 582.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium aluminosilicate. 582.2727 Section 582.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  3. 21 CFR 182.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium aluminosilicate. 182.2727 Section 182.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  4. 21 CFR 582.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium aluminosilicate. 582.2727 Section 582.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  5. 21 CFR 582.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium aluminosilicate. 582.2727 Section 582.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  6. 21 CFR 182.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium aluminosilicate. 182.2727 Section 182.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  7. 21 CFR 182.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium aluminosilicate. 182.2727 Section 182.2727...) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2727 Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance. This substance is generally recognized...

  8. 21 CFR 182.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium aluminosilicate. 182.2727 Section 182.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  9. 21 CFR 582.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium aluminosilicate. 582.2727 Section 582.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  10. 21 CFR 582.2727 - Sodium aluminosilicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium aluminosilicate. 582.2727 Section 582.2727 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Sodium aluminosilicate. (a) Product. Sodium aluminosilicate (sodium silicoaluminate). (b) Tolerance....

  11. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  12. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  13. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  14. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  15. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  16. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  17. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  18. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  19. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  20. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as...

  1. Evaluation of Uranium Coprecipitation with Sodium Aluminosilicate Phases

    SciTech Connect

    Oji, Lawrence N.; Williams, Adrienne L.

    2004-02-15

    Batch laboratory experiments performed to evaluate uranium incorporation into aluminosilicate structures during synthesis are described. This research was conducted in response to plant problems related to the accumulation of uranium with aluminosilicates in low-level radioactive waste evaporators. Conditions that favor precipitation of aluminosilicates also foster uranium solid precipitation, so it is difficult to attribute problems with uranium accumulation to, for example, only the formation of the aluminosilicates. Infrared spectra show that sodium uranates, uranium silicates, and other uranium solids are formed during the synthesis of sodium aluminosilicates structures in the presence of uranium. Both amorphous and sodalite aluminosilicate phases, unlike the zeolite A phase, show appreciable affinity for uranium incorporation during their formation in the presence of uranium.

  2. Evaluation of Uranium Co-precipitations with Sodium Aluminosilicate Phases

    SciTech Connect

    Oji, L.N.

    2003-06-24

    This paper describes batch laboratory experiments performed to evaluate uranium incorporation into aluminosilicate structures during synthesis. This research was conducted in response to plant problems related to the accumulation of uranium with aluminosilicates in low-level radioactive waste evaporators. We have found that conditions which favor precipitation of aluminosilicates also foster uranium solid precipitation, so it is difficult to attribute problems with uranium accumulation to say just the formation of the aluminosilicates. Infrared spectra shows that sodium uranates, uranium silicates and other uranium solids are formed during the synthesis of sodium aluminosilicates structures in the presence of uranium. Both amorphous and sodalite aluminosilcate phases, unlike zeolite A phase, show appreciable affinity for uranium incorporation during their formation in the presence of uranium.

  3. Uranium Sorption on Sodium Aluminosilicates and Gibbsite

    SciTech Connect

    Duff, M.C.

    2003-02-11

    At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility (DWPF). The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. After evaporation, the waste concentrate is transferred to one or more receipt storage tanks. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicates (NAS) solids that contained elementally enriched uranium (U) precipitates. The scale deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Little is known about U interactions with NAS in HLW solutions. Hence, this research was conducted to improve our basic understanding of one possible mechanism for U accumulation in the evaporators and in other SRS process areas. These studies will help support the basis for the continued safe operation of SRS evaporators and provide information on other issues associated with U behavior in the tank farms. For example, the knowledge of such fundamental information could help mitigate U accumulation during evaporator operation and optimize saltcake dissolution.

  4. Evaluation of the Incorporation of Uranium into Sodium Aluminosilicate Phases

    SciTech Connect

    Oji, L.N.

    2003-03-26

    This report describes batch laboratory experiments performed to determine the relative amounts of uranium incorporated in aluminosilicate structures during synthesis. The findings summarized here are based on laboratory experiments, which involved the synthesis of sodium aluminosilicates (NAS) structures, amorphous, zeolites A and sodalite phases in the presence of depleted uranium and the analytical search for incorporated uranium in NAS internal structures after synthesis. These studies will support the basis for continued operation of evaporators at the Savannah River Site (SRS).

  5. Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance

    SciTech Connect

    Poirier, M.; Burket, P.

    2015-11-01

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodium aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the tests showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.

  6. SODIUM ALUMINOSILICATE FOULING AND CLEANING OF DECONTAMINATED SALT SOLUTION COALESCERS

    SciTech Connect

    Poirier, M; Thomas Peters, T; Fernando Fondeur, F; Samuel Fink, S

    2008-10-28

    During initial non-radioactive operations at the Modular Caustic Side Solvent Extraction Unit (MCU), the pressure drop across the decontaminated salt solution coalescer reached {approx}10 psi while processing {approx}1250 gallons of salt solution, indicating possible fouling or plugging of the coalescer. An analysis of the feed solution and the 'plugged coalescer' concluded that the plugging was due to sodium aluminosilicate solids. MCU personnel requested Savannah River National Laboratory (SRNL) to investigate the formation of the sodium aluminosilicate solids (NAS) and the impact of the solids on the decontaminated salt solution coalescer. Researchers performed developmental testing of the cleaning protocols with a bench-scale coalescer container 1-inch long segments of a new coalescer element fouled using simulant solution. In addition, the authors obtained a 'plugged' Decontaminated Salt Solution coalescer from non-radioactive testing in the MCU and cleaned it according to the proposed cleaning procedure. Conclusions from this testing include the following: (1) Testing with the bench-scale coalescer showed an increase in pressure drop from solid particles, but the increase was not as large as observed at MCU. (2) Cleaning the bench-scale coalescer with nitric acid reduced the pressure drop and removed a large amount of solid particles (11 g of bayerite if all aluminum is present in that form or 23 g of sodium aluminosilicate if all silicon is present in that form). (3) Based on analysis of the cleaning solutions from bench-scale test, the 'dirt capacity' of a 40 inch coalescer for the NAS solids tested is calculated as 450-950 grams. (4) Cleaning the full-scale coalescer with nitric acid reduced the pressure drop and removed a large amount of solid particles (60 g of aluminum and 5 g of silicon). (5) Piping holdup in the full-scale coalescer system caused the pH to differ from the target value. Comparable hold-up in the facility could lead to less effective

  7. SODIUM ALUMINOSILICATE SOLIDS AFFINITY FOR CESIUM AND ACTINIDES

    SciTech Connect

    Peters, T; Bill Wilmarth, B; Samuel Fink, S

    2007-07-31

    Washed sodium-aluminosilicate (NAS) solids at initial concentrations of 3.55 and 5.4 g/L sorb or uptake virtually no cesium over 288 hours, nor do any NAS solids generated during that time. These concentrations of solids are believed to conservatively bound current and near-term operations. Hence, the NAS solids should not have affected measurements of the cesium during the mass transfer tests and there is minimal risk of accumulating cesium during routine operations (and hence posing a gamma radiation exposure risk in maintenance). With respect to actinide uptake, it appears that NAS solids sorb minimal quantities of uranium - up to 58 mg U per kg NAS solid. The behavior with plutonium is less well understood. Additional study may be needed for radioactive operations relative to plutonium or other fissile component sorption or trapping by the solids. We recommend this testing be incorporated in the planned tests using samples from Tank 25F and Tank 49H to extend the duration to bound expected inventory time for solution.

  8. Aqueous dissolution of sodium aluminosilicate geopolymers derived from metakaolin

    NASA Astrophysics Data System (ADS)

    Aly, Z.; Vance, E. R.; Perera, D. S.

    2012-05-01

    In dilute aqueous solutions, the elemental releases of Na, Al and Si from a metakaolin-based sodium aluminosilicate geopolymer were not very sensitive to pH in the range of 4-10 but increased outside this range, particularly on the acidic side. To minimise pH drifts, experiments were carried out using small amounts of graded powders in relatively large volumes of water. In deionised water, the Na dissolution rate in 7 days was dominant and increased by at least a factor of ˜4 on heating from 18 to 90 °C, with greater increases in the extractions of Al and Si. At 18 °C the elemental extractions in deionised water increased approximately linearly with time over the 1-7 days period. Further exposure led to a slower extraction into solution for Na and Si, with a decrease in extraction of Al. It was deduced that framework dissolution was important in significantly acidic or alkaline solutions, but that contributions from water transfer from pores to elemental extractions were present, even at low temperatures in neutral solutions. It was also deduced from the Na release data that the Na leaching kinetics of geopolymer in deionised water (dilute solutions) followed the pseudo-second-order kinetic model and the pseudo-second-order rate constant evaluated. Contact with KCl, KHCO3, and pH ˜6 and 10 potassium phthalate buffer solutions gave rise to a high degree of Na+ ↔ K+ exchange and rendered the framework ions less leachable in water.

  9. Use of natural and synthetic aluminosilicates in decontamination of feed contaminated by fungi and micotoxins.

    PubMed

    Kołacz, R; Dobrzański, Z; Kulok, M

    2004-01-01

    The contamination of feed with micotoxin has been a serious problem in animal nutrition. Many existing methods of decontamination are not satisfying due to the toxicological safety and health quality of the fodder materials. It stimulates the scientists to search for the new methods. The use of sorbents in the form of natural and synthetic aluminosilicates is a promising direction. The efficacy of aluminosilicates towards aflatoxins has been proved. However, their influence on other micotoxins is not that obvious. According to the last investigations, the use of aluminosilicates in nutrition does not cause any side effects and widespread pathological effects are observed only when dosage is incorrect. Regarding the analyses that were published, it can be supposed that the addition of several different aluminosilicates is a sufficient protection against mycotoxicoses.

  10. Corrosion behavior of sodium aluminosilicate glasses and crystals

    NASA Astrophysics Data System (ADS)

    Hamilton, James Patrick

    1999-12-01

    A comprehensive study of the effects of structure and composition on the pH-dependent corrosion behavior of sodium-aluminosilicate glasses and crystals at 25°C, was investigated by a combination of various solution and surface analysis techniques. These techniques were used to measure solution stoichiometry relative to the glass and crystal, surface composition, surface layer thickness, and structure of the surface layer. The room temperature dissolution rates of glasses and crystals with the albite composition (NaAlSi3O8) were essentially identical over the acidic-weakly basic pH region. Differences in density and tetrahedral ring structure between the glass and crystal structures, however, led to more extensive Na and Al depletion from the glass surface. Nevertheless, the outermost 17A of the glass and crystal surface were compositionally similar, suggesting that this region of the solid controls the dissolution rate. The corrosion behavior of glasses in the NBO (Na2O-xAl 2O3-(3-x)SiO2) and mineral (Na2O-Al 2O3-y SiO2) series were investigated over the pH range of 1--12. The NBO glass series tested the effects of alumina and non-bridging oxygen (NBO) concentration on corrosion behavior without any change in soda content. The mineral glass series tested the effect of Al/Si ratio on corrosion behavior in glasses with fully polymerized structures and no NBO sites. The elimination of some NBO sites by the initial addition of alumina to the glass with x = 0.0 composition caused a significant reduction in the dissolution rate. However, the dissolution rates of glasses with x > 0.2 (in the NBO series) and all glasses in the mineral series were controlled by Al-O-Si and Si-O-Si bonding. In the NBO series, NBO concentration controlled the formation and thickness of leached surface layers. In the absence of NBO sites, Al-O-Si and Si-O-Si bonding controlled the leaching behavior. Transformation of the glass surfaces during corrosion at any pH led to the formation leached

  11. Phase evolution of Na2O-Al2O3-SiO2-H2O gels in synthetic aluminosilicate binders.

    PubMed

    Walkley, Brant; San Nicolas, Rackel; Sani, Marc-Antoine; Gehman, John D; van Deventer, Jannie S J; Provis, John L

    2016-04-01

    This study demonstrates the production of stoichiometrically controlled alkali-aluminosilicate gels ('geopolymers') via alkali-activation of high-purity synthetic amorphous aluminosilicate powders. This method provides for the first time a process by which the chemistry of aluminosilicate-based cementitious materials may be accurately simulated by pure synthetic systems, allowing elucidation of physicochemical phenomena controlling alkali-aluminosilicate gel formation which has until now been impeded by the inability to isolate and control key variables. Phase evolution and nanostructural development of these materials are examined using advanced characterisation techniques, including solid state MAS NMR spectroscopy probing (29)Si, (27)Al and (23)Na nuclei. Gel stoichiometry and the reaction kinetics which control phase evolution are shown to be strongly dependent on the chemical composition of the reaction mix, while the main reaction product is a Na2O-Al2O3-SiO2-H2O type gel comprised of aluminium and silicon tetrahedra linked via oxygen bridges, with sodium taking on a charge balancing function. The alkali-aluminosilicate gels produced in this study constitute a chemically simplified model system which provides a novel research tool for the study of phase evolution and microstructural development in these systems. Novel insight of physicochemical phenomena governing geopolymer gel formation suggests that intricate control over time-dependent geopolymer physical properties can be attained through a careful precursor mix design. Chemical composition of the main N-A-S-H type gel reaction product as well as the reaction kinetics governing its formation are closely related to the Si/Al ratio of the precursor, with increased Al content leading to an increased rate of reaction and a decreased Si/Al ratio in the N-A-S-H type gel. This has significant implications for geopolymer mix design for industrial applications. PMID:26911317

  12. Phase evolution of Na2O-Al2O3-SiO2-H2O gels in synthetic aluminosilicate binders.

    PubMed

    Walkley, Brant; San Nicolas, Rackel; Sani, Marc-Antoine; Gehman, John D; van Deventer, Jannie S J; Provis, John L

    2016-04-01

    This study demonstrates the production of stoichiometrically controlled alkali-aluminosilicate gels ('geopolymers') via alkali-activation of high-purity synthetic amorphous aluminosilicate powders. This method provides for the first time a process by which the chemistry of aluminosilicate-based cementitious materials may be accurately simulated by pure synthetic systems, allowing elucidation of physicochemical phenomena controlling alkali-aluminosilicate gel formation which has until now been impeded by the inability to isolate and control key variables. Phase evolution and nanostructural development of these materials are examined using advanced characterisation techniques, including solid state MAS NMR spectroscopy probing (29)Si, (27)Al and (23)Na nuclei. Gel stoichiometry and the reaction kinetics which control phase evolution are shown to be strongly dependent on the chemical composition of the reaction mix, while the main reaction product is a Na2O-Al2O3-SiO2-H2O type gel comprised of aluminium and silicon tetrahedra linked via oxygen bridges, with sodium taking on a charge balancing function. The alkali-aluminosilicate gels produced in this study constitute a chemically simplified model system which provides a novel research tool for the study of phase evolution and microstructural development in these systems. Novel insight of physicochemical phenomena governing geopolymer gel formation suggests that intricate control over time-dependent geopolymer physical properties can be attained through a careful precursor mix design. Chemical composition of the main N-A-S-H type gel reaction product as well as the reaction kinetics governing its formation are closely related to the Si/Al ratio of the precursor, with increased Al content leading to an increased rate of reaction and a decreased Si/Al ratio in the N-A-S-H type gel. This has significant implications for geopolymer mix design for industrial applications.

  13. STUDIES OF POTENTIAL INHIBITORS OF SODIUM ALUMINOSILICATE SCALES IN HIGH-LEVEL WASTE EVAPORATION

    SciTech Connect

    Wilmarth, B; Lawrence Oji, L; Terri Fellinger, T; David Hobbs, D; Nilesh Badheka, N

    2008-02-27

    The Savannah River Site (SRS) has 49 underground storage tanks used to store High Level Waste (HLW). The tank space in these tanks must be managed to support the continued operation of key facilities. The reduction of the tank volumes in these tanks are accomplished through the use of three atmospheric pressure HLW evaporators. For a decade, evaporation of highly alkaline HLW containing aluminum and silicates has produced sodium aluminosilicate scales causing both operation and criticality hazards in the 2H Evaporator System. Segregation of aluminum-rich wastes from silicate-rich wastes minimizes the amount of scale produced and reduces cleaning expenses, but does not eliminate the scaling nor increases operation flexibility in waste process. Similar issues have affected the aluminum refining industry for many decades. Over the past several years, successful commercial products have been identified to eliminate aluminosilicate fouling in the aluminum industry, but have not been utilized in a nuclear environment. Laboratory quantities of three proprietary aluminosilicate scale inhibitors have been produced and been shown to prevent formation of scales. SRNL has been actively testing these potential inhibitors to examine their radiation stability, radiolytic degradation behaviors, and downstream impacts to determine their viability within the HLW system. One of the tested polymers successfully meets the established criteria for application in the nuclear environment. This paper will describe a summary of the methodology used to prioritize laboratory testing protocols based on potential impacts/risks identified for inhibitor deployment at SRS.

  14. Fate of Uranium during Sodium Aluminosilicate Formation under Waste Tank Conditions

    SciTech Connect

    Wilmarth, B

    2005-06-22

    Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted. Lastly, analysis of the uranium speciation in a Tank 49H set of samples showed the uranium to be soluble. Analysis of the solution composition and subsequent use of the Hobb's uranium solubility model indicated a uranium solubility limit of 32 mg/L. The measured value of uranium in the Tank 49H matched the model prediction.

  15. Structure and properties of sodium aluminosilicate glasses from molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Xiang, Ye; Du, Jincheng; Smedskjaer, Morten M.; Mauro, John C.

    2013-07-01

    Addition of alumina to sodium silicate glasses considerably improves the mechanical properties and chemical durability and changes other properties such as ionic conductivity and melt viscosity. As a result, aluminosilicate glasses find wide industrial and technological applications including the recent Corning® Gorilla® Glass. In this paper, the structures of sodium aluminosilicate glasses with a wide range of Al/Na ratios (from 1.5 to 0.6) have been studied using classical molecular dynamics simulations in a system containing around 3000 atoms, with the aim to understand the structural role of aluminum as a function of chemical composition in these glasses. The short- and medium-range structures such as aluminum coordination, bond angle distribution around cations, Qn distribution (n bridging oxygen per network forming tetrahedron), and ring size distribution have been systematically studied. In addition, the mechanical properties including bulk, shear, and Young's moduli have been calculated and compared with experimental data. It is found that aluminum ions are mainly four-fold coordinated in peralkaline compositions (Al/Na < 1) and form an integral part of the rigid silicon-oxygen glass network. In peraluminous compositions (Al/Na > 1), small amounts of five-fold coordinated aluminum ions are present while the concentration of six-fold coordinated aluminum is negligible. Oxygen triclusters are also found to be present in peraluminous compositions, and their concentration increases with increasing Al/Na ratio. The calculated bulk, shear, and Young's moduli were found to increase with increasing Al/Na ratio, in good agreement with experimental data.

  16. Atomic mobility in calcium and sodium aluminosilicate melts at 1200 °C

    NASA Astrophysics Data System (ADS)

    Claireaux, Corinne; Chopinet, Marie-Hélène; Burov, Ekaterina; Gouillart, Emmanuelle; Roskosz, Mathieu; Toplis, Michael J.

    2016-11-01

    Multicomponent chemical diffusion in liquids of the quaternary system CaO-Na2O-Al2O3-SiO2 has been studied. Diffusion-couple experiments were performed at 1200 °C and for different durations around a central composition of 64.5 wt%SiO2, 13.3 wt%Na2O, 10.8 wt%CaO, 11.4 wt%Al2O3, leading to an overconstrained system of equations that was used to determine the diffusion matrix of the system. The dominant eigenvector of the diffusion matrix was found to correspond to the exchange between sodium and calcium, consistent with the results of the ternary soda-lime silica system. On the other hand, neither of the other two eigenvectors of the diffusion matrix of the quaternary system involve sodium. Given a factor of 50 between the dominant and second eigenvalue, diffusion couples involving the exchange of sodium oxide and a network-forming oxide result in strong uphill diffusion of calcium. The second eigenvector, corresponding to the exchange of calcium with silicon and aluminum, is close to the dominant eigenvector found in previous studies of ternary alkaline-earth aluminosilicate systems. Our results therefore suggest that simple systems may be used to understand diffusive mechanisms in more complex systems.

  17. A New Titanium-Bearing Calcium Aluminosilicate Phase. 1; Meteoritic Occurrences and Formation in Synthetic Systems

    NASA Technical Reports Server (NTRS)

    Paque, Julie M.; Beckett, John R.; Barber, David J.; Stolper, Edward M.

    1994-01-01

    A new titanium-bearing calcium aluminosilicate mineral has been identified in coarse-grained calcium-aluminum-rich inclusions (CAIs) from carbonaceous chondrites. The formula for this phase, which we have temporarily termed "UNK," is Ca3Ti(AlTi)2(Si,Al)3O14, and it is present in at least 8 of the 20 coarse-grained CAIs from the Allende CV3 chondrite examined as part of this project. The phase occurs in Types A and B1 inclusions as small tabular crystals oriented along two mutually perpendicular planes in melilite. UNK crystallizes from melts in dynamic crystallization experiments conducted in air from four bulk compositions modeled after Types A, B1, B2 and C inclusions. Cooling rates resulting in crystallization of UNK ranged from 0.5 to 200 C/h from maximum (initial) temperatures of 1375 to 1580 C. Only below 1190 C does UNK itself begin to crystallize. To first order, the presence or absence of UNK from individual experiments can be understood in terms of the compositions of residual melts and nucleation probabilities. Compositions of synthetic and meteoritic LINK are very similar in terms of major oxides, differing only in the small amounts of trivalent Ti (7-13% of total Ti) in meteoritic samples. UNK crystallized from the Type A analog is similar texturally to that found in CAls, although glass, which is typically associated with synthetic UN& is not observed in meteoritic occurrences. A low Ti end-member of UNK ("Si-UNK") with a composition new that of Ca3Al2Si4O14 was produced in a few samples from the Type B1 analog. This phase has not been found in the meteoritic inclusions.

  18. Effect of hydrated sodium calcium aluminosilicates on aflatoxicosis in broiler chicks.

    PubMed

    Kubena, L F; Harvey, R B; Phillips, T D; Clement, B A

    1993-04-01

    In three experiments, three different hydrated sodium calcium aluminosilicates (HSCAS) were incorporated into chick diets (.5%) containing either 0 or 5.0 (Experiments 1 and 2) or 0 or 2.5 (Experiment 3) mg/kg aflatoxin (AF). Male broiler chicks consumed their respective diets and water ad libitum from 1 to 21 days of age. When compared with controls, body weights in chicks receiving 5.0 mg AF/kg were reduced by 214 g in Experiment 1 and 220 g in Experiment 2. The addition of .5% of the HSCAS compounds significantly diminished the growth inhibitory effects caused by AF by 39 to 68% in Experiment 1, by 46 to 88% in Experiment 2, and by 38 to 90% in Experiment 3. The increases in relative organ weights and the decreases in serum biochemical values caused by AF were significantly diminished to differing degrees by all three of the HSCAS compounds. These data demonstrate that these specific HSCAS compounds can be protective against the effects of AF in young growing broilers and further emphasizes the fact that all silicate-type sorbents are not equal in their ability to protect against aflatoxicosis. It also seems possible to specially process compounds to increase their efficacy for protection against the toxicity of AF.

  19. Effects of Thermal and Pressure Histories on the Chemical Strengthening of Sodium Aluminosilicate Glass

    NASA Astrophysics Data System (ADS)

    Svenson, Mouritz; Thirion, Lynn; Youngman, Randall; Mauro, John; Bauchy, Mathieu; Rzoska, Sylwester; Bockowski, Michal; Smedskjaer, Morten

    2016-03-01

    Glasses can be chemically strengthened through the ion exchange process, wherein smaller ions in the glass (e.g., Na+) are replaced by larger ions from a salt bath (e.g., K+). This develops a compressive stress (CS) on the glass surface, which, in turn, improves the damage resistance of the glass. The magnitude and depth of the generated CS depends on the thermal and pressure histories of the glass prior to ion exchange. In this study, we investigate the ion exchange-related properties (mutual diffusivity, CS, and hardness) of a sodium aluminosilicate glass, which has been densified through annealing below the initial fictive temperature of the glass or through pressure-quenching from the glass transition temperature at 1 GPa prior to ion exchange. We show that the rate of alkali interdiffusivity depends only on the density of the glass, rather than on the applied densification method. However, we also demonstrate that for a given density, the increase in CS and increase in hardness induced by ion exchange strongly depends on the densification method. Specifically, at constant density, the CS and hardness values achieved through thermal annealing are larger than those achieved through pressure-quenching. These results are discussed in relation to the structural changes in the environment of the network-modifier and the overall network densification.

  20. Effects of a hydrated sodium calcium aluminosilicate (T-Bind) on mycotoxicosis in young broiler chickens.

    PubMed

    Kubena, L F; Harvey, R B; Bailey, R H; Buckley, S A; Rottinghaus, G E

    1998-10-01

    Experiments were conducted to determine the ability of a hydrated sodium calcium aluminosilicate (T-Bind) sorbent to reduce the toxicity of aflatoxins (AF) or T-2 toxin in male broiler chickens from day of hatch to 21 d of age. In Experiment 1, the sorbent was added at 0.250 or 0.375% to diets containing AF at 5 or T-2 toxin at 8 mg/kg of diet. When compared with controls, AF reduced BW gain by 27% and T-2 toxin reduced BW gain by 17%. The addition of the sorbent at 0.250 or 0.375%, in the absence of added mycotoxins, did not alter the performance of the chicks. The sorbent reduced the toxic effects of 5 mg AF/kg of diet on BW gain by 43% but did not significantly diminish the toxic effects of 8 mg T-2 toxin/kg of diet. The decreased efficiency of feed utilization and the increased relative organ weights caused by AF were significantly diminished to differing degrees by the sorbent. Oral lesions caused by T-2 toxin were not affected by the sorbent. In Experiment 2, the sorbent was added at 0.80% to a diet containing 8 mg T-2 toxin/kg of diet. The sorbent did not diminish the toxic effects of T-2 toxin when added at 0.80% of the diet. These data demonstrate that this specific sorbent can provide protection against the toxicity of AF, but not T-2 toxin, in young broiler chicks.

  1. Analysis of Tank 38H (HTF-38-14-150, 151) and Tank 43H (HTF- 43-14-152, 53) Surface and Subsurface Supernatant Samples in Support of Enrichment Control, Corrosion Control and Sodium Aluminosilicate Formation Potential Programs

    SciTech Connect

    Oji, L. N.

    2015-01-14

    This report provides the results of analyses on Tanks 38H and 43H surface and subsurface supernatant liquid samples in support of the Enrichment Control Program (ECP), the Corrosion Control Program and Sodium Aluminosilicate Formation Potential in the Evaporator.

  2. Sodium sulfate corrosion of silicon carbide fiber-reinforced lithium aluminosilicate glass-ceramic matrix composites. Master's thesis

    SciTech Connect

    Maldia, L.C.

    1993-12-01

    Sodium sulfate hot corrosion of a SiC fiber-reinforced lithium aluminosilicate (LAS) glass-ceramic matrix composite was studied using Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). Changes in the microstructural chemical composition of the specimens were investigated. The samples provided by Naval Air Warfare Center (NAWC), Warminster, PA were grouped as follows: (1) as-received, (2) Na2SO4 salt-coated and heat-treated in oxygen, (3) noncoated and heat-treated in oxygen, (4) Na2SO4. Salt-coated and heat-treated in argon, and (5) noncoated and heat-treated in argon. Heat treatment was performed by NAWC for 100 hours at 900 deg C. Experimental data obtained indicated that the presence of Na2SO4 in an oxidative environment resulted in rapid corrosion of the matrix and SiC fibers and in the latter rings of SiO2 replaced what had previously been SiC. There was very limited degradation of the fibers and matrix exposed at the surface in the noncoated sample heat-treated in oxygen and in the salt-coated sample heat-treated in argon. A significant reduction in the amount of mullite in the matrices of all heat-treated samples was observed. Mullite dissolved into either the glassy phase or into the Beta-spodumene matrix. Lastly, the presence of distinct magnesium silicate crystalline phases in the salt-coated and heat-treated in oxygen sample implies that the MgO at the surface reacted with the SiO2 in the matrix.

  3. Effects of the degree of polymerization on the structure of sodium silicate and aluminosilicate glasses and melts: An 17O NMR study

    NASA Astrophysics Data System (ADS)

    Lee, Sung Keun; Stebbins, Jonathan F.

    2009-02-01

    Revealing the atomic structure and disorder in oxide glasses, including sodium silicates and aluminosilicates, with varying degrees of polymerization, is a challenging problem in high-temperature geochemistry as well as glass science. Here, we report 17O MAS and 3QMAS NMR spectra for binary sodium silicate and ternary sodium aluminosilicate glasses with varying degrees of polymerization (Na 2O/SiO 2 ratio and Na 2O/Al 2O 3 ratio), revealing in detail the extent of disorder (network connectivity and topological disorder) and variations of NMR parameters with the glass composition. In binary sodium silicate glasses [Na 2O- k(SiO 2)], the fraction of non-bridging oxygens (NBOs, Na-O-Si) increases with the Na 2O/SiO 2 ratio ( k), as predicted from the composition. The 17O isotropic chemical shifts ( 17O δiso) for both bridging oxygen (BO) and NBO increase by about 10-15 ppm with the SiO 2 content (for k = 1-3). The quadrupolar coupling products of BOs and NBOs also increase with the SiO 2 content. These trends suggest that both NBOs and BOs strongly interact with Na; therefore, the Na distributions around BOs and NBOs are likely to be relatively homogenous for the glass compositions studied here, placing some qualitative limits on the extent of segregation of alkali channels from silica-enriched regions as suggested by modified random-network models. The peak width (in the isotropic dimension) and thus bond angle and length distributions of Si-O-Si and Na-O-Si increase with the SiO 2 content, indicating an increase in the topological disorder with the degree of polymerization. In the ternary aluminosilicate glasses [Na 2O] x[Al 2O 3] 1-xSiO 2, the NBO fraction decreases while the Al-O-Si and Al-O-Al fractions apparently increase with increasing Al 2O 3 content. The variation of oxygen cluster populations suggests that deviation from "Al avoidance" is more apparent near the charge-balanced join (Na/Al = 1). The Si-O-Si fraction, which is closely related to the activity

  4. The role of Al3+ on rheology and structural changes in sodium silicate and aluminosilicate glasses and melts

    NASA Astrophysics Data System (ADS)

    Le Losq, Charles; Neuville, Daniel R.; Florian, Pierre; Henderson, Grant S.; Massiot, Dominique

    2014-02-01

    Because of their importance in both the geosciences and the glass-making industry, alkali aluminosilicate melts have been the focal point of many past studies, but despite progress many problems remain unresolved, such as the complex behaviour of the thermodynamic properties of aluminium-rich alkali silicate melts. This paper presents a study of Na2O-Al2O3-SiO2 glasses and melts, containing 75 mol% SiO2 and different Al/(Al + Na) ratios. Their structure has been investigated by using Raman spectroscopy, as well as, 23Na, 27Al and 29Si 1D MAS NMR spectroscopy. Results confirm the role change of Na+ cations from network modifier to charge compensator in the presence of Al3+ ions. In addition, polymerization increases with increase of the Al/(Al + Na) ratio. These structural changes explain the observed variations in the viscosity of these melts. The viscosity data in turn allow us to calculate the configurational entropy of melts at the glass transition temperature [the Sconf(Tg)]. The variations of the Sconf(Tg) are strongly nonlinear, with sharp increases and decreases depending on the Al/(Al + Na) ratio. More importantly, a strong increase of the Sconf(Tg) is observed when a few Al2O3 is added to sodium silicate melt. A strong decrease is observed after crossing the tectosilicate join, when Al/(Al + Na) > 0.5 and when Al3+ ions are present in fivefold coordination, Al[5], in the glass. Furthermore, in situ27Al NMR spectra of the peraluminous melt show a clear increase of the Al[5] concentration with increasing temperature. When considered in combination with melt fragility and heat capacity, our data demonstrate that Al[5] is clearly a transient unit at high temperature in highly polymerized tectosilicate and peraluminous melts. However, when present in glasses, Al[5] increases the stability of the aluminosilicate network, hence the Tg of glasses. This could be explained by the ability of Al[5] to carry threefold coordinated oxygen atoms in its first coordination

  5. The role of Al3+ on rheology and structural changes in sodium silicate and aluminosilicate glasses and melts

    NASA Astrophysics Data System (ADS)

    Le Losq, Charles; Neuville, Daniel R.; Florian, Pierre; Henderson, Grant S.; Massiot, Dominique

    2014-02-01

    Because of their importance in both the geosciences and the glass-making industry, alkali aluminosilicate melts have been the focal point of many past studies, but despite progress many problems remain unresolved, such as the complex behaviour of the thermodynamic properties of aluminium-rich alkali silicate melts. This paper presents a study of Na2O-Al2O3-SiO2 glasses and melts, containing 75 mol% SiO2 and different Al/(Al + Na) ratios. Their structure has been investigated by using Raman spectroscopy, as well as, 23Na, 27Al and 29Si 1D MAS NMR spectroscopy. Results confirm the role change of Na+ cations from network modifier to charge compensator in the presence of Al3+ ions. In addition, polymerization increases with increase of the Al/(Al + Na) ratio. These structural changes explain the observed variations in the viscosity of these melts. The viscosity data in turn allow us to calculate the configurational entropy of melts at the glass transition temperature [the Sconf(Tg)]. The variations of the Sconf(Tg) are strongly nonlinear, with sharp increases and decreases depending on the Al/(Al + Na) ratio. More importantly, a strong increase of the Sconf(Tg) is observed when a few Al2O3 is added to sodium silicate melt. A strong decrease is observed after crossing the tectosilicate join, when Al/(Al + Na) > 0.5 and when Al3+ ions are present in fivefold coordination, Al[5], in the glass. Furthermore, in situ27Al NMR spectra of the peraluminous melt show a clear increase of the Al[5] concentration with increasing temperature. When considered in combination with melt fragility and heat capacity, our data demonstrate that Al[5] is clearly a transient unit at high temperature in highly polymerized tectosilicate and peraluminous melts. However, when present in glasses, Al[5] increases the stability of the aluminosilicate network, hence the Tg of glasses. This could be explained by the ability of Al[5] to carry threefold coordinated oxygen atoms in its first coordination

  6. Comparison of the sequestering properties of yeast cell wall extract and hydrated sodium calcium aluminosilicate in three in vitro models accounting for the animal physiological bioavailability of zearalenone.

    PubMed

    Yiannikouris, A; Kettunen, H; Apajalahti, J; Pennala, E; Moran, C A

    2013-01-01

    The sequestration/inactivation of the oestrogenic mycotoxin zearalenone (ZEA) by two adsorbents--yeast cell wall extract (YCW) and hydrated sodium calcium aluminosilicate (HSCAS)--was studied in three laboratory models: (1) an in vitro model was adapted from referenced methods to test for the sequestrant sorption capabilities under buffer conditions at two pH values using liquid chromatography coupled to a fluorescence detector for toxin quantification; (2) a second in vitro model was used to evaluate the sequestrant sorption stability according to pH variations and using ³H-labelled ZEA at low toxin concentration; and (3) an original, ex vivo Ussing chamber model was developed to further understand the transfer of ZEA through intestinal tissue and the impact of each sequestrant on the mycotoxin bioavailability of ³H-labelled ZEA. YCW was a more efficient ZEA adsorbent than HSCAS in all three models, except under very acidic conditions (pH 2.5 or 3.0). The Ussing chamber model offered a novel, ex vivo, alternative method for understanding the effect of sequestrant on the bioavailability of ZEA. The results showed that compared with HSCAS, YCW was more efficient in sequestering ZEA and that it reduced the accumulation of ZEA in the intestinal tissue by 40% (p < 0.001).

  7. Efficiency of hydrated sodium calcium aluminosilicate to ameliorate the adverse effects of graded levels of aflatoxin B1 in broiler chicks.

    PubMed

    Chen, X; Horn, N; Applegate, T J

    2014-08-01

    The objective of this study was to evaluate the efficiency of a hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to ameliorate the adverse effects of 0.5 to 2 mg of aflatoxin B1 (AFB1)/kg in broiler chicks. The study consisted of 8 dietary treatments, including 4 concentrations of AFB1 (0, 0.5, 1, and 2 mg/kg) with or without HSCAS (0.5%) fed to 8 replicate cages per diet (6 males chicks per cage) from 0 to 21 d of age. Cumulative feed intake, BW gain (P < 0.0001), and G:F (P = 0.004) of birds fed the 2 mg of AFB1/kg of diet were significantly lower in comparison with birds fed 0 to 1 mg of AFB1/kg. Relative liver weight was increased in the 2 mg of AFB1/kg group (P < 0.0001). Dietary HSCAS improved cumulative BW gain (main effect P = 0.06), particularly from 14 to 21 d of age (P = 0.037). Dietary HSCAS also reversed the increase in relative liver weight for birds fed AFB1 (P = 0.019). Dietary AFB1 negatively affected major serum parameters (albumin, total protein, globulin, phosphorus, glucose, alkaline phosphatase, and creatine phosphokinase), whereas supplementation with HSCAS partially alleviated the affected serum biochemistry. In addition, serum complement activity and liver gene expression were negatively affected by 2 mg of AFB1/kg. The HSCAS supplement increased the liver expression of catalase and superoxide dismutase (P < 0.05). Results from this study indicate that dietary supplementation with HSCAS can effectively improve BW gain and partially ameliorate aflatoxicosis for broiler chicks fed AFB1-contaminated feeds.

  8. Steam Reforming Technology Demonstration for Conversion of DOE Sodium-Bearing Tank Wastes at Idaho National Laboratory into a Leach-Resistant Alkali Aluminosilicate Waste Form

    SciTech Connect

    Ryan, K.; Bradley Mason, J.; Evans, B.; Vora, V.; Olson, A.

    2008-07-01

    The patented THOR{sup R} fluidized-bed steam reforming (FBSR) technology was selected by the U.S. Department of Energy (DOE) for treatment of sodium-bearing waste (SBW) in the Integrated Waste Treatment Unit (IWTU), currently under construction at the Idaho National Laboratory (INL) Site.1 SBW is an acidic waste created primarily from cleanup of the fuel reprocessing equipment at the Idaho Nuclear Technology and Engineering Center (INTEC) at the INL. The SBW contains high concentrations of nitric acid, and alkali and aluminum nitrates, along with many other inorganic compounds, including substantial levels of radionuclides. As part of the implementation of the THOR{sup R} process at INTEC, an engineering-scale technology demonstration (ESTD) was conducted using a specially designed pilot plant located at Hazen Research, Inc. in Golden Colorado. This ESTD confirmed the efficacy of the THOR{sup R} FBSR process to convert the SBW into a granular carbonate-based waste form suitable for disposal at the Waste Isolation Pilot Plant (WIPP). DOE authorized, as a risk reduction measure, the performance of an additional ESTD to demonstrate the production of an insoluble mineralized product, in the event that an alternate disposition path is required. The additional ESTD was conducted at the Hazen Research facility using the THOR{sup R} process and the same SBW simulant employed previously. An alkali aluminosilicate mineral product was produced that exhibited excellent leach resistance and chemical durability. The demonstration established general system operating parameters for a full-scale facility; provided process off-gas data that confirmed operation within regulatory limits; determined that the mineralized product exhibits superior leach resistance and durability, compared to Environmental Assessment (EA) and Low-activity Reference Material (LRM) glasses, as indicated by the Product Consistency Test (PCT); ascertained that Cs and Re (a surrogate for Tc) were non

  9. Microprobes aluminosilicate ceramic membranes

    DOEpatents

    Anderson, Marc A.; Sheng, Guangyao

    1993-01-01

    Methods have been developed to make mixed alumina-silicate and aluminosilicate particulate microporous ceramic membranes. One method involves the making of separate alumina and silica sols which are then mixed. Another method involves the creation of a combined sol with aluminosilicate particles. The resulting combined alumina and silica membranes have high surface area, a very small pore size, and a very good temperature stability.

  10. Reduction of ozone oxidants in synthetic seawater by use of sodium thiosulfate

    SciTech Connect

    Hemdal, J.F. )

    1992-01-01

    Ozone gas was dissolved in synthetic seawater at various concentrations. The toxicity of the resultant ozone oxidants on Brachionus sp. rotifers was noted. The time to 50% mortality ranged from 10 min for an oxidant concentration of 9.0 mg/L to more than 23 h for a 0.43-mg/L concentration. Sodium thiosulfate was added to water samples containing known toxic concentrations of ozone oxidants. One milligram of sodium thiosulfate neutralized 0.16-1.13 mg of ozone oxidants depending on the length of time the sample was aerated before thiosulfate was added: the longer the aeration, the less effectively thiosulfate neutralized oxidants. In samples in which the oxidants were fully neutralized by sodium thiosulfate, the time to 50% rotifer mortality was comparable to that in control samples never exposed to ozone. 7 refs., 3 tabs.

  11. Aluminosilicate Precipitation Impact on Uranium

    SciTech Connect

    WILMARTH, WILLIAM

    2006-03-10

    Experiments have been conducted to examine the fate of uranium during the formation of sodium aluminosilicate (NAS) when wastes containing high aluminate concentrations are mixed with wastes of high silicate concentration. Testing was conducted at varying degrees of uranium saturation. Testing examined typical tank conditions, e.g., stagnant, slightly elevated temperature (50 C). The results showed that under sub-saturated conditions uranium is not removed from solution to any large extent in both simulant testing and actual tank waste testing. This aspect was not thoroughly understood prior to this work and was necessary to avoid criticality issues when actual tank wastes were aggregated. There are data supporting a small removal due to sorption of uranium on sites in the NAS. Above the solubility limit the data are clear that a reduction in uranium concentration occurs concomitant with the formation of aluminosilicate. This uranium precipitation is fairly rapid and ceases when uranium reaches its solubility limit. At the solubility limit, it appears that uranium is not affected, but further testing might be warranted.

  12. [Simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction and high performance liquid chromatography].

    PubMed

    Zhao, Fei; Gao, Guanghui; Na, Haiqiu; Ma, Dianjun; Wang, Xiaoli

    2013-05-01

    A method for the simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction (SPE) and high performance liquid chromatography with variable wavelengths was established. After degreased with petroleum ether, extracted, purified with SPE, and concentrated, the sample was separated on a C18 column with a gradient elution of 0.02 mol/L ammonium acetate and methanol, and detected at 230, 510, 484 and 510 nm, separately. The saccharin sodium and synthetic colours were separated with this method. The recoveries were 88.6% - 97.1% with the RSD < 5%. The limit of detection was 0.05 mg/kg for all the analytes. The proposed method is simple, reliable and reproducible, and especially suitable for a lot of sample detections of saccharin sodium and synthetic colours in flavourings.

  13. Functionalized Amorphous Aluminosilicates

    NASA Astrophysics Data System (ADS)

    Mesgar, Milad

    Alkali treated aluminosilicate (geopolymer) was functionalized by surfactant to increase the hydrophobicity for making Pickering emulsion for the first part of this work. In the first part of this study, alkali treated metakaolin was functionalized with cetyltrimethylammonium bromide ((C16H33)N(CH 3)3Br, CTAB). The electrostatic interaction between this quaternary ammonium and the surface of the aluminosilicate which has negative charge has taken place. The particles then were used to prepare Pickering emulsion. The resulting stable dispersions, obtained very fast at very simple conditions with low ratio of aluminosilicate to liquid phase. In the second part, the interaction between geopolymer and glycerol was studied to see the covalent grafting of the geopolymer for making geopolymer composite. The composite material would be the basis material to be used as support catalyst, thin coating reagent and flame retardant material and so on, Variety of techniques, Thermogravimetric (TGA), Particle-induced X-ray emission (PIXE), FTIR, Solid state NMR, Powder X-ray diffraction (PXRD), BET surface area, Elemental analysis (CHN), TEM, SEM and Optical microscopy were used to characterize the functionalized geopolymer.

  14. XPS study of distribution of elements between surface and volume in aluminosilicate catalysts and adsorbents

    SciTech Connect

    Chukin, G.D.; Grishin, S.A.; Kulikov, A.S.; Nefedov, B.K.; Surin, S.A.

    1986-02-01

    X-ray photoelectron spectroscopy (XPS) has been used in an investigation of the distribution of aluminum and sodium on the surface and in the volume of amorphous aluminosilicates. It has been shown that in the Na form of the aluminosilicates, the sodium and aluminum ions are localized preferentially on the surface. When the Na/sup +/ ions are replaced by protons, there is a change in the electronic state of the near-surface atoms in the aluminosilicates. Information on acidic centers that has been obtained by IR spectroscopy is consistent with the XPS data.

  15. Results of Aluminosilicate Inhibitor Testing

    SciTech Connect

    Wilmarth, W.R.

    2001-06-27

    The aluminosilicate scale in the 2H Evaporator has precluded operation since late 1999. The chemistry of scale formation is known but the mechanism(s) for deposition are not well understood. Tests have been conducted to determine if chemical agents could prevent aluminosilicate formation under conditions similar to Tank 43H. Additionally, particle growth inhibition is also tested.

  16. Solubilizing functionalized molecular aluminosilicates.

    PubMed

    Rascón-Cruz, Fernando; Huerta-Lavorie, Raúl; Jancik, Vojtech; Toscano, Rubén Alfredo; Cea-Olivares, Raymundo

    2009-02-21

    Molecular aluminosilicate Al(SH)(micro-O)Si(OH)(O(t)Bu)(2) ( = [HC{C(Me)N(Ar)}(2)](-), Ar = 2,6-(i)Pr(2)C(6)H(3)) has been prepared from Al(SH)(2) and ((t)BuO)(2)Si(OH)(2) in high yield. When reacted with one equiv. of water, the unique aluminosilicate containing two terminal hydroxy groups Al(OH.THF)(mu-O)Si(OH)(O(t)Bu)(2) can be isolated. However, when is reacted with the bulkier silanol ((t)BuO)(3)SiOH, no reaction is observed. The desired Al(SH)(micro-O)Si(O(t)Bu)(3) can be prepared in a two-step synthesis between AlH(2) and ((t)BuO)(3)SiOH giving first Al(H)(micro-O)Si(O(t)Bu)(3), which reacts further with elemental sulfur to give as the only product. Direct hydrolysis of was conducted to obtain Al(OH)(micro-O)Si(O(t)Bu)(3), however, such hydrolysis always resulted in a complete decomposition of the starting material. Therefore we used boric acid, which condenses in non-polar solvents and slowly evolve water, to hydrolyze to under mild conditions. Compounds , and have been characterized by single-crystal X-ray diffraction.

  17. Synthesis and characterization of aluminosilicate catalyst impregnated by nickel oxide

    NASA Astrophysics Data System (ADS)

    Maulida, Iffana Dani; Sriatun, Taslimah

    2015-09-01

    Aluminosilicate as a catalyst has been synthesized by pore-engineering using CetylTrimethylAmmonium-Bromide (CTAB) as templating agent. It can produce bigger aluminosilicate pore therefore it will be more suitable for bulky molecule. The aims of this research are to synthesize aluminosilicate supported by Nickel, using CTAB surfactant as templating agent for larger pore radius than natural zeolite and characterize the synthesis product, consist of total acid sites and surface area characteristic. This research has been done with following steps. First, making sodium silicate and sodium aluminate. Second, aluminosilicate was synthesized by direct methods, calcined at 550, 650 and 750°C variation temperature, characterized product by X-RD and FTIR spectrometer. Third, NiCl2 was impregnated to the aluminosilicate that has the best cristallinity and main TO4 functional groups product (550 sample). Variation of NiCl2:aluminosilicate (w/w) ratio were 25%:75%, 50%:50% and 75%:25%. Last but not least characterization of catalytic properties was performed. It comprised total acidity test (gravimetric method) and Surface Area Analyzer. The result shows that the product synthesized by direct method at 550oC calcination temperature has the best cristallinity and main functional groups of TO4. The highest total acid sites was 31.6 mmole/g (Imp-A sample). Surface Area Analyzer shows that Imp-B sample has the best pore distribution and highest total pore volume and specific surface area with value 32.424 cc/g and 46.8287 m2/g respectively. We can draw the conclusion that the most potential catalyst is Imp-A sample compared to Imp-B and Imp-C because it has the highest total acid sites. However the most effective catalyst used for product selectivity was Imp-B sample among all samples.

  18. Results of Aluminosilicate Formation Testing

    SciTech Connect

    Wilmarth, W.R.

    2001-09-11

    The purpose of this work was to examine several experimental parameters of the formation of aluminosilicates under several tank chemistries, examine the conversion of crystalline phases, and determine inherent solubilities of certain crystal phases.

  19. Nanostructure of gel-derived aluminosilicate materials.

    PubMed

    Sinkó, Katalin; Hüsing, Nicola; Goerigk, Günter; Peterlik, Herwig

    2008-02-01

    In the present work, aluminosilicate aerogels prepared under various conditions were compared with respect to their nanostructures and porosity. The purpose of this investigation was to find a suitable way to predict the final product structure and to tailor a required texture. Several Al and Si precursors (Al nitrate, Al isopropoxide, Al acetate, tetraethoxysilane (TEOS), and sodium silicate) were used in our examinations; the solvent content (water and alcohols), surfactants, as well as the catalysts were varied. In addition, the aerogels were subjected to various heat treatments. Hybrid aerogels were synthesized by the addition of different polymers (poly(acrylic acid), polyvinyl acetate, and polydimethylsiloxane). Aluminosilicate and hybrid aerogel structures were investigated by 27Al MAS NMR, SAXS, SEM, and porosity measurements. Loose fractal structures with a good porosity and high Al incorporation can be achieved from TEOS and Al nitrate or isopropoxide via a sol-gel preparation route. The use of Al acetate led to compact aerogel structures independently of the Si precursor, the pH, and the catalyst.

  20. Uranium and Aluminosilicate Surface Precipitation Tests

    SciTech Connect

    Hu, M.Z.

    2002-11-27

    The 2H evaporator at the Savannah River Site has been used to treat an aluminum-rich waste stream from canyon operations and a silicon-rich waste stream from the Defense Waste Processing Facility. The formation of aluminosilicate scale in the evaporator has caused significant operational problems. Because uranium has been found to accumulate in the aluminosilicate solids, the scale deposition has introduced criticality concerns as well. The objective of the tests described in this report is to determine possible causes of the uranium incorporation in the evaporator scale materials. The scope of this task is to perform laboratory experiments with simulant solutions to determine if (1) uranium can be deposited on the surfaces of various sodium aluminosilicate (NAS) forms and (2) aluminosilicates can form on the surfaces of uranium-containing solids. Batch experiments with simulant solutions of three types were conducted: (1) contact of uranium solutions/sols with NAS coatings on stainless steel surfaces, (2) contact of uranium solutions with NAS particles, and (3) contact of precipitated uranium-containing particles with solutions containing aluminum and silicon. The results show that uranium can be incorporated in NAS solids through encapsulation in bulk agglomerated NAS particles of different phases (amorphous, zeolite A, sodalite, and cancrinite) as well as through heterogeneous deposition on the surfaces of NAS coatings (amorphous and cancrinite) grown on stainless steel. The results also indicate that NAS particles can grow on the surfaces of precipitated uranium solids. Particularly notable for evaporator operations is the finding that uranium solids can form on existing NAS scale, including cancrinite solids. If NAS scale is present, and uranium is in sufficient concentration in solution to precipitate, a portion of the uranium can be expected to become associated with the scale. The data obtained to date on uranium-NAS affinity are qualitative. A necessary

  1. Photoelastic response of alkaline earth aluminosilicate glasses.

    PubMed

    Smedskjaer, Morten M; Saxton, Scott A; Ellison, Adam J; Mauro, John C

    2012-02-01

    Understanding the structural origins of the photoelastic response in oxide glasses is important for discovering new families of zero-stress optic glasses and for developing a predictive physical model. In this Letter, we have investigated the composition dependence of the stress optic coefficient C of 32 sodium aluminosilicate glasses with different types of alkaline earth oxides (MgO, CaO, SrO, and BaO). We find that most of the composition dependence of the stress optic response can be captured by a linear regression model and that the individual contributions from the alkaline earths to C depend on the alkaline earth-oxygen bond metallicity. High bond metallicity is required to allow bonds to be distorted along both the bonding direction and perpendicular to it. These findings are valuable for understanding the photoelastic response of oxide glasses.

  2. Characterization of Uranium Solids Precipitated with Aluminosilicates

    SciTech Connect

    DUFF, MC

    2004-04-29

    At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation.

  3. 40 CFR 721.633 - Aluminosilicates, phospho-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aluminosilicates, phospho-. 721.633... Substances § 721.633 Aluminosilicates, phospho-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Aluminosilicates, phospho- (PMN P-98-1275; CAS...

  4. 40 CFR 721.633 - Aluminosilicates, phospho-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aluminosilicates, phospho-. 721.633... Substances § 721.633 Aluminosilicates, phospho-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Aluminosilicates, phospho- (PMN P-98-1275; CAS...

  5. 40 CFR 721.633 - Aluminosilicates, phospho-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aluminosilicates, phospho-. 721.633... Substances § 721.633 Aluminosilicates, phospho-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Aluminosilicates, phospho- (PMN P-98-1275; CAS...

  6. 40 CFR 721.633 - Aluminosilicates, phospho-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aluminosilicates, phospho-. 721.633... Substances § 721.633 Aluminosilicates, phospho-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Aluminosilicates, phospho- (PMN P-98-1275; CAS...

  7. 40 CFR 721.633 - Aluminosilicates, phospho-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aluminosilicates, phospho-. 721.633... Substances § 721.633 Aluminosilicates, phospho-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Aluminosilicates, phospho- (PMN P-98-1275; CAS...

  8. [Comparison of the thermostability of natural (sulfoprolamine and sodium usnate) and synthetic (climbazole and piroctone olamine) antidandruff agents].

    PubMed

    Coiffard, C; Coiffard, L; de Roeck-Holtzhauer, Y

    1999-09-01

    We compared thermostability of various natural (sulfoprolamine and sodium usnate) or synthetic (climbazol and piroctone olamine) antidandruff agents in aqueous diluted solution at pH around 7. Thermodegradation of these solutions was studied by an isothermal method in thermostatically controlled ovens, at three temperatures (50, 70 and 90 degrees C). For each molecule, we determined at 20 degrees C t90% (time necessary to obtain a decrease of 10% of the initial concentration, value which shows the stability of the product). The present study shows that piroctone olamine is the most stable antidandruff agent among those studied. PMID:10520510

  9. Amphiphilic properties of poly(oxyalkylene)amine-intercalated smectite aluminosilicates.

    PubMed

    Lin, Jiang-Jen; Chen, Yu-Min

    2004-05-11

    Layered aluminosilicates, including synthetic fluorine mica and natural montmorillonite (MMT), were intercalated with poly(oxypropylene)-polyamine quaternary salts with a 230-5000 molecular weight range. The X-ray basal spacing of these silicates had been expanded from 13.5 to 83.7 A for the synthetic mica and to 92.0 A for MMT. The relative silicate dimensions (300-1000 nm for synthetic mica and 80-100 nm for MMT) were ascertained by direct TEM observations in the case of the co-intercalated synthetic mica and MMT mixtures with Mw = 2000 quaternary ammonium salts. The tailored organic incorporation of synthetic mica and MMT clays could alter these hydrophilic clays, making them amphiphilic, and enable the lowering of toluene/water interfacial tension to 2.0 mN/m at the critical concentration of 0.1 wt %.

  10. Sodium

    MedlinePlus

    ... sodium. Doctors recommend you eat less than 2.4 grams per day. That equals about 1 teaspoon of table salt a day. Reading food labels can help you see how much sodium is in prepared foods. NIH: National Heart, Lung, and Blood Institute

  11. Novel synthetic sulfoglycolipid IG20 facilitates exocytosis in chromaffin cells through the regulation of sodium channels.

    PubMed

    Crespo-Castrillo, Andrea; Punzón, Eva; de Pascual, Ricardo; Maroto, Marcos; Padín, Juan Fernando; García-Álvarez, Isabel; Nanclares, Carmen; Ruiz-Pascual, Lucía; Gandía, Luis; Fernández-Mayoralas, Alfonso; García, Antonio G

    2015-12-01

    In search of druggable synthetic lipids that function as potential modulators of synaptic transmission and plasticity, we synthesized sulfoglycolipid IG20, which stimulates neuritic outgrowth. Here, we have explored its effects on ion channels and exocytosis in bovine chromaffin cells. IG20 augmented the rate of basal catecholamine release. Such effect did not depend on Ca(2+) mobilization from intracellular stores; rather, IG20-elicited secretion entirely dependent on Ca(2+) entry through L-subtype voltage-activated Ca(2+) channels. Those channels were recruited by cell depolarization mediated by IG20 likely through its ability to enhance the recruitment of Na(+) channels at more hyperpolarizing potentials. Confocal imaging with fluorescent derivative IG20-NBD revealed its rapid incorporation and confinement into the plasmalemma, supporting the idea that IG20 effects are exerted through a plasmalemmal-delimited mechanism. Thus, synthetic IG20 seems to mimic several physiological effects of endogenous lipids such as regulation of ion channels, Ca(2+) signaling, and exocytosis. Therefore, sulfoglycolipid IG20 may become a pharmacological tool for investigating the role of the lipid environment on neuronal excitability, ion channels, neurotransmitter release, synaptic efficacy, and neuronal plasticity. It may also inspire the synthesis of druggable sulfoglycolipids aimed at increasing synaptic plasticity and efficacy in neurodegenerative diseases and traumatic brain-spinal cord injury. The novel synthetic sulfoglycolipid IG20 mimics several physiological effects of endogenous lipids such as regulation of ion channels, Ca(2+) signaling, and exocytosis. This profile may eventually drive enhanced synaptic plasticity and efficacy.

  12. Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sukenaga, Sohei; Kanehashi, Koji; Shibata, Hiroyuki; Saito, Noritaka; Nakashima, Kunihiko

    2016-08-01

    The structural roles of alkali and calcium cations are important for understanding the physical and chemical properties of aluminosilicate melts and glasses. Recently, oxygen-17 nuclear magnetic resonance (17O NMR) studies of calcium-sodium aluminosilicate glasses showed that these structural roles are not randomly given, but rather each cation has its own preferential role. However, the relationship between cation type and role preference in calcium aluminosilicate glass is not completely understood. In the present study, the structural roles of lithium, sodium, and potassium cations in selected calcium aluminosilicate glasses are investigated using 17O solid-state NMR experiments. Data from these experiments clearly show that potassium cations have a notably stronger tendency to act as charge compensators within the network structure, compared to sodium and lithium cations. The result of 17O NMR experiment also showed that sodium and lithium cations in part act as network modifier alongside with calcium cations.

  13. Direct aerosol synthesis of large-pore amorphous mesostructured aluminosilicates with superior acid-catalytic properties.

    PubMed

    Pega, Stéphanie; Boissière, Cédric; Grosso, David; Azaïs, Thierry; Chaumonnot, Alexandra; Sanchez, Clément

    2009-01-01

    An old dream comes true: A direct and environmentally benign synthetic strategy was developed for the aerosol-based mass production of large-pore mesostructured aluminosilicate powders (see TEM image). Although amorphous, some powders exhibit higher activity towards m-xylene isomerization and lower coke formation than a Y-zeolite based industrial reference catalyst.

  14. [Raman active vibrations of aluminosilicates].

    PubMed

    Pan, Feng; Yu, Xue-hui; Mo, Xuan-xue; You, Jing-lin; Wang, Chen; Chen, Hui; Jiang, Guo-chang

    2006-10-01

    Raman spectra of aluminosilicate minerals, namely kyanite, andalusite, and sillimanite and K2O-Al2O3-SiO2 glasses were recorded. Four alumino-silicon tetrahedral model clusters were calculated by self-consistent (SCF) molecular orbital ab-ini-tio calculation of the quantum chem (QC) method. The result shows a decrease tendency in Raman frequencies in the 800-1200 cm(-1) frequency region with increase in four-coordinated Al content, which is assigned to the Si--Onb symmetry stretching vibrations. The Raman spectra in the 700-800 cm(-1) frequency region is attributed to Al-Onb symmetry stretching vibrations. PMID:17205741

  15. Water behaviour in nanoporous aluminosilicates.

    PubMed

    Smirnov, Konstantin S; Bougeard, Daniel

    2010-07-21

    This paper briefly reviews results of molecular dynamics simulation studies of water confined in nanoporous aluminosilicates. The behaviour of confined molecules is shown to be influenced by the nature of the host structure, and the size and the topology of the voids. For some of the systems discussed the ambiguity in results of different modelling studies call for the use of extended potential and structural models. Thus, the use of polarizable force fields was shown to be necessary to take into account the variation of the molecular dipole of confined molecules in different environments. PMID:21399287

  16. [Raman active vibrations of aluminosilicates].

    PubMed

    Pan, Feng; Yu, Xue-hui; Mo, Xuan-xue; You, Jing-lin; Wang, Chen; Chen, Hui; Jiang, Guo-chang

    2006-10-01

    Raman spectra of aluminosilicate minerals, namely kyanite, andalusite, and sillimanite and K2O-Al2O3-SiO2 glasses were recorded. Four alumino-silicon tetrahedral model clusters were calculated by self-consistent (SCF) molecular orbital ab-ini-tio calculation of the quantum chem (QC) method. The result shows a decrease tendency in Raman frequencies in the 800-1200 cm(-1) frequency region with increase in four-coordinated Al content, which is assigned to the Si--Onb symmetry stretching vibrations. The Raman spectra in the 700-800 cm(-1) frequency region is attributed to Al-Onb symmetry stretching vibrations.

  17. Water behaviour in nanoporous aluminosilicates.

    PubMed

    Smirnov, Konstantin S; Bougeard, Daniel

    2010-07-21

    This paper briefly reviews results of molecular dynamics simulation studies of water confined in nanoporous aluminosilicates. The behaviour of confined molecules is shown to be influenced by the nature of the host structure, and the size and the topology of the voids. For some of the systems discussed the ambiguity in results of different modelling studies call for the use of extended potential and structural models. Thus, the use of polarizable force fields was shown to be necessary to take into account the variation of the molecular dipole of confined molecules in different environments.

  18. Ultrastable Mesoporous Aluminosilicates by Grafting Routes.

    PubMed

    Mokaya

    1999-10-01

    A combination of postsynthesis grafting and hydrothermal treatment offers an excellent route for the synthesis of ultrastable mesoporous aluminosilicates with enhanced acidity and catalytic activity. The stability observed (>150 h in boiling water; 4 h at 1000 degrees C) is, for mesoporous silicates, remarkable. Unusually the hydrothermal treatment is beneficial with respect to the use of the stable aluminosilicates as solid acid catalysts.

  19. Characterization of Uranium Solids Precipitated with Aluminosilicates

    SciTech Connect

    DUFF, MC

    2004-01-09

    At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation. To learn more about the interaction between U(VI) and NAS in HLW salt solutions, we performed several fundamental studies to examine the mechanisms of U accumulation with NAS in highly caustic solutions. This larger group of studies focused on the following processes: co-precipitation/structural incorporation, sorption, and precipitation (with or without NAS), which will be reviewed in this presentation. We will present and discuss local atomic structural characterization data about U that has been co-precipitated with NAS solids (such as amorphous zeolite precursor material and sodalite) using X-ray absorption fine-structure (XAFS) spectroscopic techniques.

  20. Sodium butyrate and its synthetic amide derivative modulate nociceptive behaviors in mice.

    PubMed

    Russo, Roberto; De Caro, Carmen; Avagliano, Carmen; Cristiano, Claudia; La Rana, Giovanna; Mattace Raso, Giuseppina; Berni Canani, Roberto; Meli, Rosaria; Calignano, Antonio

    2016-01-01

    In the present study we investigated the role of sodium butyrate (butyrate), and its more palatable derivative, the N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA), in animal models of acute and chronic pain. We found that oral administrations of butyrate (10-200mg/Kg) or equimolecular FBA (21.2-424mg/Kg) reduced visceral pain in a dose- and time-dependent manner. Both drugs were also effective in the formalin test, showing an antinociceptive effect. This analgesic effect was blocked by glibenclamide, suggesting the involvement of ATP-dependent K(+) channels. Moreover, following repeated administration butyrate (100-200mg/Kg) and FBA (212-424mg/Kg) retained their analgesic properties in a model of neuropathic pain, reducing mechanical and thermal hyperalgesia in the chronic constriction injury (CCI) model. The involvement of peroxisome proliferator-activated receptor (PPAR) -α and -γ for the analgesic effect of butyrate was also investigated by using PPAR-α null mice or the PPAR-γ antagonist GW9662. Western blot analysis, confirmed the role of peroxisome receptors in butyrate effects, evidencing the increase of PPAR-α and -γ expression, associated to the reduction of inflammatory markers (COX-2, iNOS, TNF-α and cFOS). In conclusion, we describe the role of butyrate-based drugs in pain, identifying different and converging non-genomic and genomic mechanisms of action, which cooperate in nociception maintenance.

  1. The Dissolution of Synthetic Na-Boltwoodite in Sodium Carbonate Solutions

    SciTech Connect

    Ilton, Eugene S.; Liu, Chongxuan; Yantasee, Wassana; Wang, Zheming; Moore, Dean A.; Felmy, Andrew R.; Zachara, John M.

    2006-09-01

    Uranyl silicates such as uranophane and Na-boltwoodite appear to control the solubility of uranium in the contaminated sediments at the US Department of Energy Hanford site (Liu et al., 2004). Consequently, the solubility of synthetic Na-boltwoodite was determined over a wide range of bicarbonate concentrations, from circumneutral to alkaline pH, that are representative of porewater and groundwater compositions at the Hanford site. Results show that Na-boltwoodite dissolution was nearly congruent and its solubility increased with increasing bicarbonate concentration. Calculated solubility constants varied by nearly 2 log units from low bicarbonate (no added NaCO3) to 50 mmol/L bicarbonate. However, the solubility constants only vary by 0.5 log units from 0 added bicarbonate to 1.2 mmol/L bicarbonate, where logKsp = 5.39-5.92 and the average logKsp = 5.63. No systematic trend in logKsp was apparent over this range in bicarbonate concentrations. LogKsp values trended down with increasing bicarbonate concentration, where logKsp = 4.06 at 50 mmol/L bicarbonate. We conclude that the calculated solubility constants at high bicarbonate are compromised by an incomplete or inaccurate uranyl-carbonate speciation model.

  2. Structure and mechanical properties of aluminosilicate geopolymer composites with Portland cement and its constituent minerals

    SciTech Connect

    Tailby, Jonathan; MacKenzie, Kenneth J.D.

    2010-05-15

    The compressive strengths and structures of composites of aluminosilicate geopolymer with the synthetic cement minerals C{sub 3}S, beta-C{sub 2}S, C{sub 3}A and commercial OPC were investigated. All the composites showed lower strengths than the geopolymer and OPC paste alone. X-ray diffraction, {sup 29}Si and {sup 27}Al MAS NMR and SEM/EDS observations indicate that hydration of the cement minerals and OPC is hindered in the presence of geopolymer, even though sufficient water was present in the mix for hydration to occur. In the absence of SEM evidence for the formation of an impervious layer around the cement mineral grains, the poor strength development is suggested to be due to the retarded development of C-S-H because of the preferential removal from the system of available Si because geopolymer formation is more rapid than the hydration of the cement minerals. This possibility is supported by experiments in which the rate of geopolymer formation is retarded by the substitution of potassium for sodium, by the reduction of the alkali content of the geopolymer paste or by the addition of borate. In all these cases the strength of the OPC-geopolymer composite was increased, particularly by the combination of the borate additive with the potassium geopolymer, producing an OPC-geopolymer composite stronger than hydrated OPC paste alone.

  3. Chlorine, in the Presence of Iron, Does Indeed Decrease the Viscosity of Aluminosilicate Melts

    NASA Astrophysics Data System (ADS)

    Webb, S. L.

    2012-12-01

    The effect of volatiles on melt rheology is investigated here, as the degassing of magma before an eruption usually leads to an increase in magma viscosity; and therefore increases the probability of an explosive eruption. There is not a large amount of data on the effect of chlorine on viscosity. It would appear, however, that chlorine increases the viscosity of peralkaline sodium-aluminosilicate melts, and decreases the viscosity of peraluminous sodium-aluminosilicate melts. These different effects of chlorine on viscosity indicate that the chlorine sits in different structural sites in peraluminous and peralkaline melts. In previous studies of rheology in this laboratory, we have shown that chlorine does indeed increase the viscosity of a phonolite analog Na2O-CaO-Al2O3-SiO2 melt. In this study, we have extended our investigation of the rheology of chlorine-bearing melts to basaltic compositions. The melt composition used here is that of a basaltic glass taken from the mid-Atlantic Ridge at 3000 m depth during the Venture Cruise (Ireland) of 2011. The viscosities were determined using the micropenetration technique in the 109-1012 Pa s range at temperatures 600-800 C. It was found that the addition of 0.6 wt% Cl resulted in a 0.5 log unit decrease in viscosity. A synthetic haplo-basaltic melt with the iron replaced by Mg and the Al was also synthesized. The addition of 0.3 wt% chlorine to this melt resulted in a 0.3 log unit increase in viscosity; as observed previously for Fe-free peralkaline melts. Based on these viscosity data it would appear that the effect of chlorine on rheology is a function of the composition of the melt, and that the structural site taken by chlorine varies as a function of the presence or absence of iron. The addition of chlorine to the iron-bearing melt, increased the Fe2+/Fetot from 0.30 to 0.45. This indicates that the presence of chlorine results in an energetic preference for Fe2+ in the melt structure. Thus, it is not so much the

  4. Synthesis and biological characterization of synthetic analogs of Huwentoxin-IV (Mu-theraphotoxin-Hh2a), a neuronal tetrodotoxin-sensitive sodium channel inhibitor.

    PubMed

    Deng, Meichun; Luo, Xuan; Jiang, Liping; Chen, Hanchun; Wang, Jun; He, Hailun; Liang, Songping

    2013-09-01

    Huwentoxin-IV (HWTX-IV, also named Mu-theraphotoxin-Hh2a) is a typical inhibitor cystine knot peptide isolated from the venom of Chinese tarantula Ornithoctonus huwena and is found to inhibit tetrodotoxin-sensitive (TTX-S) sodium channels from mammalian sensory neurons. This peptide binds to neurotoxin receptor site 4 located at the extracellular S3-S4 linker of domain II in neuronal sodium channels. However, the molecular surface of HWTX-IV interaction with sodium channels remains unknown. In this study, we synthesized HWTX-IV and three mutants (T28D, R29A and Q34D) and characterized their functions on TTX-S sodium channels from adult rat dorsal root ganglion (DRG) neurons. Analysis of liquid chromatography, mass spectrometry and circular dichroism spectrum indicated that all four synthetic peptides are properly folded. Synthetic HWTX-IV exhibited the same activity as native HWTX-IV, while three mutations reduced toxin binding affinities by 10-200 fold, indicating that the basic or vicinal polar residues Thr²⁸, Arg²⁹, and Gln³⁴ in C-terminus might play critical roles in the interaction of HWTX-IV with TTX-S sodium channels. PMID:23726857

  5. Aluminosilicate Formation in High Level Waste Evaporators: A Mechanism for Uranium Accumulation

    SciTech Connect

    Wilmarth, W.R.

    2002-02-08

    High level waste Evaporators at the Savannah River Site (SRS) process radioactive waste to concentrate supernate and thus conserve tank space. In June of 1997, difficulty in evaporator operation was initially observed. This operational difficulty evidenced itself as a plugging of the evaporator's gravity drain line (GDL). The material blocking the GDL was determined to be a sodium aluminosilicate. Following a mechanical cleaning of the GDL, the evaporator was returned to service until October 1999. At this time massive deposits were discovered in the evaporator pot. As a result of the changes in evaporator chemistry and the resulting formation of aluminosilicate deposits in the evaporator, a comprehensive research and development program has been undertaken. This program is underway in order to assist in understanding the new evaporator chemistry and gain insight into the deposition phenomena. Key results from testing in FY01 have demonstrated that the chemistry of the evaporator feed favors aluminosilicate formation. Both the reaction kinetics and particle growth of the aluminosilicate material under SRS evaporator conditions has been demonstrated to occur within the residence times utilized in the SRS evaporator operation. Batch and continuous-flow experiments at known levels of supersaturation have shown a significant correlation between the deposition of aluminosilicates and mixing intensity in the vessel. Advances in thermodynamic modeling of the evaporator chemistry have been accomplished. The resulting thermodynamic model has been related to the operational history of the evaporator, is currently assisting in feed selection, and could potentially assist in expanding the operating envelopes technical baselines for evaporator operation.

  6. Beneficiation of aluminosilicate and magnesia secondary refractories

    SciTech Connect

    Baranovskii, N.I.; Klyachin, V.V.; Rogozina, V.G.; Bortnikova, N.V.

    1987-09-01

    This article provides a comprehensive description of the recycling, magnetic separation, and utilization of waste refractories comprised of aluminosilicate and magnesia refractories along with data on the properties pertinent to the efficiency of the recycling process.

  7. Shape selectivity extending to ordered supermicroporous aluminosilicates.

    PubMed

    Fu, Wen Hua; Liang, Xiao Min; Zhang, Haidong; Wang, Yi Meng; He, Ming Yuan

    2015-01-28

    In the synthesis of polyoxymethylene dimethyl ethers (PODEn) catalyzed by ordered supermicroporous aluminosilicates, shape selectivity was observed and the high selectivity for target products (PODE3-8) was attributed to the particular pore diameter.

  8. Dissolution and Separation of Aluminum and Aluminosilicates

    SciTech Connect

    McFarlane, Joanna; Benker, Dennis; DePaoli, David W.; Felker, Leslie Kevin; Mattus, Catherine H.

    2015-12-19

    The selection of an aluminum alloy for target irradiation affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the dissolver, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. Aluminosilicate dissolution presents challenges in a number of different areas, metals extraction from minerals, flyash treatment, and separations from aluminum alloys. We present experimental work that attempts to maximize dissolution of aluminum metal, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as a function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. Our data have been compared with published calculations of aluminum phase diagrams. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution.

  9. Dissolution and Separation of Aluminum and Aluminosilicates

    DOE PAGESBeta

    McFarlane, Joanna; Benker, Dennis; DePaoli, David W.; Felker, Leslie Kevin; Mattus, Catherine H.

    2015-12-19

    The selection of an aluminum alloy for target irradiation affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the dissolver, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. Aluminosilicate dissolution presents challenges in a number of different areas, metals extraction from minerals, flyash treatment, and separations from aluminum alloys. We present experimental work that attempts to maximize dissolution of aluminum metal, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as amore » function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. Our data have been compared with published calculations of aluminum phase diagrams. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution.« less

  10. Sorption of cesium ions by nanostructured calcium aluminosilicates

    NASA Astrophysics Data System (ADS)

    Gordienko, P. S.; Shabalin, I. A.; Yarusova, S. B.; Suponina, A. P.; Zhevtun, I. G.

    2016-10-01

    Data on the sorption properties of synthetic calcium aluminosilicates (CASes) with Al: Si ratios of 2: 2, 2: 6, and 2: 10, fabricated within the multicomponent system CaCl2-AlCl3-KOM-SiO2-H2O, are presented. Isotherms of the sorption of Cs+ ions from aqueous solutions with Cs+ concentrations of 0.2 to 6.0 mmol L-1 are analyzed. The CAS maximum sorption capacity and the Langmuir constants are determined. Kinetic data are obtained, and the energy of cation-exchange activation upon the sorption of Cs+ ions is determined. The effect of a salt background (1% KCl + 6% NaCl) has on the values of distribution coefficient ( K d) and the degree of Cs+ ion removal is established.

  11. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  12. Intrinsic differences in atomic ordering of calcium (alumino)silicate hydrates in conventional and alkali-activated cements

    SciTech Connect

    White, Claire E.; Daemen, Luke L.; Hartl, Monika; Page, Katharine

    2015-01-15

    The atomic structures of calcium silicate hydrate (C–S–H) and calcium (–sodium) aluminosilicate hydrate (C–(N)–A–S–H) gels, and their presence in conventional and blended cement systems, have been the topic of significant debate over recent decades. Previous investigations have revealed that synthetic C–S–H gel is nanocrystalline and due to the chemical similarities between ordinary Portland cement (OPC)-based systems and low-CO{sub 2} alkali-activated slags, researchers have inferred that the atomic ordering in alkali-activated slag is the same as in OPC–slag cements. Here, X-ray total scattering is used to determine the local bonding environment and nanostructure of C(–A)–S–H gels present in hydrated tricalcium silicate (C{sub 3}S), blended C{sub 3}S–slag and alkali-activated slag, revealing the large intrinsic differences in the extent of nanoscale ordering between C–S–H derived from C{sub 3}S and alkali-activated slag systems, which may have a significant influence on thermodynamic stability, and material properties at higher length scales, including long term durability of alkali-activated cements.

  13. Surface and interface investigation of aluminosilicate biomaterial by the “in vivo” experiments

    NASA Astrophysics Data System (ADS)

    Oudadesse, H.; Derrien, A. C.; Martin, S.; Chaair, H.; Cathelineau, G.

    2008-11-01

    Porous mixtures of aluminosilicate/calcium phosphate have been studied for biomaterials applications. Aluminosilicates formed with an inorganic polymeric constitution present amorphous zeolites because of their 3D network structure and present the ability to link to bone matrix. Amorphous geopolymers of the potassium-poly(sialate)-nanopolymer type were synthesised at low temperature and studied for their use as potential biomaterials. They were mixed with 13% weight of calcium phosphate like biphasic hydroxyapatite and β-tricalcium phosphate. In this study, " in vivo" experiments were monitored to evaluate the biocompatibility, the surface and the interface behaviour of these composites when used as bone implants. Moreover, it has been demonstrated using histological and physicochemical studies that the developed materials exhibited a remarkable bone bonding when implanted in a rabbit's thighbone for a period of 1 month. The easy synthesis conditions (low temperature) of this composite and the fast intimate links with bone constitute an improvement of synthetic bone graft biomaterial.

  14. Studies of the surface charge of amorphous aluminosilicates using surface complexation models.

    PubMed

    Jara, Alejandra A; Goldberg, Sabine; Mora, M L

    2005-12-01

    Synthetic noncrystalline aluminosilicates with variable charge, similar to allophanes present naturally in volcanic soils, were studied. The surface charge behavior was determined by zero point charge (ZPC) measured by electrophoretic mobility (isoelectric points, IEP) and determined by potentiometric titration (point of zero salt effect, PZSE). The ZPC calculated by Parks model (ZPC(c)), compared with IEP values, showed that the aluminosilicate (AlSi) surface was slightly enriched by AlOH (34% Al(2)O(3) and 66% SiO(2)) compared with the bulk composition (29% Al(2)O(3) and 71% SiO(2)). For aluminosilicate coated with iron oxide (AlSiFe) the ZPC(c) (4.4) was lower than the IEP (8.46), showing that the surface composition is formed mainly from iron oxide. The PZSE values for AlSi and AlSiFe were 6.2 and 4.8, respectively. The differences between the IEP and PZSE are attributed to the formation of Si-O-Fe or Si-O-Al bonds; therefore, the reactivity of Fe and Al atoms was modified on the surface. Two mechanistic models, the constant capacitance model (CCM) and the triple layer model (TLM), using the program FITEQL 3.2 were able to describe the surface behavior of both synthetic aluminosilicates. The acidity constants determined using both models for the aluminosilicates showed differences with respect to pure oxide, mainly attributed to the presence of SiOH sites on the internal surfaces. The ionic strength showed a good relation with the parameters obtained using the CCM (pK(int)(a1), pK(int)(a2) and capacitance values) and the TLM (pK(int)(a1), pK(int)(a2), pK(int)(Cl-), pK(int)(K+), and inner capacitance) for both aluminosilicates. However, the TLM was able to describe the acidity and complexation constants better since it considered the formation of the outer sphere complex between the background electrolyte and the surface. Then, the TLM makes it possible to describe real systems.

  15. Characterization of Uranium Solids Precipitated with Sodium Aluminosilicates

    SciTech Connect

    Duff, M.C.

    2003-03-07

    At the Savannah River Site, the High-Level Waste Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage.

  16. Treatment of a synthetic solution of galvanization effluent via the conversion of sodium cyanide into an insoluble safe complex.

    PubMed

    Ismail, Ibrahim; Abdel-Monem, Nabil; Fateen, Seif-Eddeen; Abdelazeem, Waleed

    2009-07-30

    Wastewater discharged from metal-finishing processes usually contains cyanide, a hazardous substance that is used extensively in the surface finishing industry. In the present study, a synthetic solution resembling the contaminated wastewater was chemically treated using ferrous sulfate. This simple one-step process was applied successfully to remove cyanide from metal finishing wastewater. The experiments were carried out on a synthetic solution containing ions of cyanide and zinc. The effects of mixing velocity, ratio of ferrous ions to cyanide ions, ferrous ions concentration, initial cyanide concentration, pH of solution, temperature, mixing time and zinc ions concentration were studied. The results showed that the removal efficiency of cyanide increased as the mixing velocity increased, ferrous ion molar ratio to cyanide ions increased, temperature increased and time of mixing increased at an optimum of pH 8. The reduction of cyanide concentration reached the allowable limit for wastewater discharge according to the Egyptian Environmental Law decree 44/2000, which is 0.2mg/l. The formed complexes were analyzed and the stability of each complex was studied under different pH value solutions after 7 days of contact. A typical example of electroplating wastewater from a local company in the field of metal finishing, which contains 18 mg/lCN(-) and 12 mg/l Zn(2+), was treated according to the determined optimum conditions for the treatment process and the concentration of CN(-) was reduced to 0.095 mg/l after 15 min of agitation. PMID:19135781

  17. Mixed alkaline earth effect in the compressibility of aluminosilicate glasses.

    PubMed

    Smedskjaer, Morten M; Rzoska, Sylwester J; Bockowski, Michal; Mauro, John C

    2014-02-01

    The mixed modifier effect (MME) in oxide glasses manifests itself as a non-additive variation in certain properties when one modifier oxide species is substituted by another one at constant total modifier content. However, the structural and topological origins of the MME are still under debate. This study provides new insights into the MME by investigating the effect of isostatic compression on density and hardness of mixed MgO/CaO sodium aluminosilicate glasses. This is done using a specially designed setup allowing isostatic compression of bulk glass samples up to 1 GPa at elevated temperature. A mixed alkaline earth effect is found in the compressibility and relative change of hardness, viz., a local maximum of density as a function of Mg/Ca ratio appears following compression, whereas a local minimum of hardness in the uncompressed glasses nearly disappears after compression. Moreover, the densification of these glasses is found to occur at temperatures much below the glass transition temperature, indicating that a non-viscous mechanism is at play. This is further supported by the fact that density relaxes in a stretched exponential manner upon subsequent annealing at ambient pressure with an exponent of ∼0.62. This is close to the Phillips value of 3/5 for relaxation in three dimensions when both short- and long-range interactions are activated.

  18. Synthetic cation transporters incorporating crown ethers and calixarenes as headgroups and central relays: a comparison of sodium and chloride selectivity†

    PubMed Central

    Iglesias-Sánchez, José Carlos; Wang, Wei; Ferdani, Riccardo; Prados, Pilar; de Mendoza, Javier

    2009-01-01

    An earlier study showed that a calix[4]arene could function as a central relay unit to form an ion conductance pathway through a phospholipid bilayer membrane. The present study expands the range of compounds from calix[4]arene to calix[6]arene and incorporates them either as central units or as headgroups, substituting one or more diaza-18-crown-6 residues in functioning hydraphiles. Ion release was assayed by detecting either Na+ or Cl− release from phospholipid vesicles. The ion transport activity for calix[4]arenes in either position is modest, but is almost non-existent when calix[6] residues were incorporated either as head groups or central relay units. The poor activity of the calix[6]arenes may result from an inability to penetrate to the midplane of the bilayer or pass entirely through it to form a conductance pathway. The transmembrane “flip-flop” may result from high polarity or steric bulk, or both. A hydraphile incorporating a single –NHCOC6H4OCH2CONH– as a central relay proved to be an excellent Na+ conductor, but less selective for Cl−. The fact that this new hydraphile molecule shows selectivity for Na + over Cl− transport and possesses two secondary amide residues in the central relay suggests a means to control ion selectivity in synthetic ion transporters. PMID:21720497

  19. Lithium alumino-silicate ion source development

    NASA Astrophysics Data System (ADS)

    Roy, Prabir Kumar; Seidl, Peter A.; Kwan, Joe W.; Greenway, Wayne G.; Waldron, William L.; Wu, James K.; Mazaheri, Kavous

    2009-11-01

    We report experimental progress on Li+ source development in preparation for warm dense matter heating experiments. To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, we are pursuing the use of a low (E < 5 MeV) kinetic energy singly ionized lithium beam and a thin target. Two kinds of lithium (Li+) alumino-silicate ion sources, β-spodumene and β-eucryptite, each of area 0.31 cm2, have been fabricated for ion emission measurements. These surface ionization sources are heated to 1200 to 1300 C where they preferentially emit singly ionized alkali ions. Tight process controls were necessary in preparing and sintering the alumino-silicate to the porous tungsten substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. Current density limit of the two kinds have been measured, and ion species identification of possible contaminants has been verified with a Wien (E x B) filter.

  20. Effects of Sodium Butyrate and Its Synthetic Amide Derivative on Liver Inflammation and Glucose Tolerance in an Animal Model of Steatosis Induced by High Fat Diet

    PubMed Central

    Mattace Raso, Giuseppina; Simeoli, Raffaele; Russo, Roberto; Iacono, Anna; Santoro, Anna; Paciello, Orlando; Ferrante, Maria Carmela; Canani, Roberto Berni; Calignano, Antonio; Meli, Rosaria

    2013-01-01

    Background & Aims Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease. Insulin resistance (IR) appears to be critical in its pathogenesis. We evaluated the effects of sodium butyrate (butyrate) and its synthetic derivative N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA) in a rat model of insulin resistance and steatosis induced by high-fat diet (HFD). Methods After weaning, young male Sprague-Dawley rats were divided into 4 groups receiving different diets for 6 weeks: 1. control group (standard diet); 2. HFD; 3. HFD plus butyrate (20 mg/kg/die) and 4. HFD plus FBA (42.5 mg/Kg/die, the equimolecular dose of butyrate). Liver tissues of the rats were analyzed by Western blot and real-time PCR. Insulin resistance, liver inflammation and Toll-like pattern modifications were determined. Results Evaluation of these two preparations of butyrate showed a reduction of liver steatosis and inflammation in HFD fed animals. The compounds showed a similar potency in the normalisation of several variables, such as transaminases, homeostasis model assessment for insulin resistance index, and glucose tolerance. Both treatments significantly reduced hepatic TNF-α expression and restored GLUTs and PPARs, either in liver or adipose tissue. Finally, FBA showed a higher potency in reducing pro-inflammatory parameters in the liver, via suppression of Toll-like receptors and NF-κB activation. Conclusions Our results demonstrated a protective effect of butyrate in limiting molecular events underlying the onset of IR and NAFLD, suggesting a potential clinical relevance for this substance. In particular, its derivative, FBA, could represent an alternative therapeutic option to sodium butyrate, sharing a comparable efficacy, but a better palatability and compliance. PMID:23861927

  1. Synthesis and characterization of inorganic polymers from the alkali activation of an aluminosilicate

    NASA Astrophysics Data System (ADS)

    González, C. P.; Montaño, A. M.; González, A. K.; Ríos, C. A.

    2014-06-01

    This paper presents the results of the synthesis and characterization of inorganic polymers (IP) from aluminosilicates: bentonite (BT) and pumice (PP). The synthesis of IP, was carried out by two methods involving alkaline activation, at room temperature and 80 ± 5 °C, using as activating agent sodium silicate both commercial and analytical (Na2SiO3). Sodium hydroxide (NaOH) at 3 M, 7 M and 12 M was added. A lower degree of polymerization was obtained by using analytical precursors subjected to room temperature and 80 ± 5°C. Replacement of heating by the use of the commercial activating agent with greater alkalinity allows the formation of a 3D network. The materials were structurally characterized by FTIR spectroscopy with Attenuated Reflectance (ATR), Scanning Electron Microscope (SEM) and X -ray diffraction (DRX).

  2. Highly effective degradation of sodium dodecylbenzene sulphonate and synthetic greywater by Fenton-like reaction over zerovalent iron-based catalyst.

    PubMed

    Zhu, Shi-Ni; Wang, Chao; Yip, Alex C K; Tsang, Daniel C W

    2015-01-01

    There is an increasing interest to recycle greywater for meeting non-portable water demand. However, linear alkylbenzene sulphonates (a form of anionic surfactants) that are commonly found in greywater are less biodegradable at moderate to high concentrations. A fenton-like system is a relatively economic advanced oxidation process that can potentially be used for surfactant degradation in greywater treatment. This study investigated the feasibility of zerovalent iron (ZVI)-mediated Fenton's oxidation of sodium dodecylbenzene sulphonate (SDBS) using Fe0/H2O2 and Fe2+/Fe0/H2O2 systems under a range of operating conditions. For the Fe0/H2O2 binary system, the initial pH value and Fe0 dosage played important roles in final degradation efficiency. For the Fe2+/Fe0/H2O2 ternary systems, a small amount of Fe2+ (0.5-1.7 mM) contributed a synergistic effect to promote iron recycling and SDBS degradation. Approximately, 90% of SDBS mineralization efficiency was accomplished within 15 min at a pH range from 3.0 to 6.5, using 18 mM Fe0 and 15 mM H2O2. However, the removal kinetics was rate-limited by Fe2+ dissolution from the ZVI surfaces. The Fenton-like process of the Fe2+/Fe0/H2O2 ternary system also presents a promising treatment method for synthetic greywater, in which 90% TOC removal was achieved within the first 10 min; 78% COD and 91% BOD5 were achieved after 120 min of reaction.

  3. Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

    SciTech Connect

    Nicholas, Christopher P; Boldingh, Edwin P

    2013-12-17

    A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  4. Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

    SciTech Connect

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-04-29

    A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  5. 29Si NMR study of structural ordering in aluminosilicate geopolymer gels.

    PubMed

    Duxson, Peter; Provis, John L; Lukey, Grant C; Separovic, Frances; van Deventer, Jannie S J

    2005-03-29

    A systematic series of aluminosilicate geopolymer gels was synthesized and then analyzed using 29Si magic-angle spinning nuclear magnetic resonance (MAS NMR) in combination with Gaussian peak deconvolution to characterize the short-range ordering in terms of T-O-T bonds (where T is Al or Si). The effect of nominal Na2O/(Na2O + K2O) and Si/Al ratios on short-range network ordering was quantified by deconvolution of the 29Si MAS NMR spectra into individual Gaussian peaks representing different Q4(mAl) silicon centers. The deconvolution procedure developed in this work is applicable to other aluminosilicate gel systems. The short-range ordering observed here indicates that Loewenstein's Rule of perfect aluminum avoidance may not apply strictly to geopolymeric gels, although further analyses are required to quantify the degree of aluminum avoidance. Potassium geopolymers appeared to exhibit a more random Si/Al distribution compared to that of mixed-alkali and sodium systems. This work provides a quantitative account of the silicon and aluminum ordering in geopolymers, which is essential for extending our understanding of the mechanical strength, chemical and thermal stability, and fundamental structure of these systems.

  6. Cellular morphology of organic-inorganic hybrid foams based on alkali alumino-silicate matrix

    NASA Astrophysics Data System (ADS)

    Verdolotti, Letizia; Liguori, Barbara; Capasso, Ilaria; Caputo, Domenico; Lavorgna, Marino; Iannace, Salvatore

    2014-05-01

    Organic-inorganic hybrid foams based on an alkali alumino-silicate matrix were prepared by using different foaming methods. Initially, the synthesis of an inorganic matrix by using aluminosilicate particles, activated through a sodium silicate solution, was performed at room temperature. Subsequently the viscous paste was foamed by using three different methods. In the first method, gaseous hydrogen produced by the oxidization of Si powder in an alkaline media, was used as blowing agent to generate gas bubbles in the paste. In the second method, the porous structure was generated by mixing the paste with a "meringue" type of foam previously prepared by whipping, under vigorous stirring, a water solution containing vegetal proteins as surfactants. In the third method, a combination of these two methods was employed. The foamed systems were consolidated for 24 hours at 40°C and then characterized by FTIR, X-Ray diffraction, scanning electron microscopy (SEM) and compression tests. Low density foams (˜500 Kg/m3) with good cellular structure and mechanical properties were obtained by combining the "meringue" approach with the use of the chemical blowing agent based on Si.

  7. Cellular morphology of organic-inorganic hybrid foams based on alkali alumino-silicate matrix

    SciTech Connect

    Verdolotti, Letizia; Capasso, Ilaria; Lavorgna, Marino; Liguori, Barbara; Caputo, Domenico; Iannace, Salvatore

    2014-05-15

    Organic-inorganic hybrid foams based on an alkali alumino-silicate matrix were prepared by using different foaming methods. Initially, the synthesis of an inorganic matrix by using aluminosilicate particles, activated through a sodium silicate solution, was performed at room temperature. Subsequently the viscous paste was foamed by using three different methods. In the first method, gaseous hydrogen produced by the oxidization of Si powder in an alkaline media, was used as blowing agent to generate gas bubbles in the paste. In the second method, the porous structure was generated by mixing the paste with a “meringue” type of foam previously prepared by whipping, under vigorous stirring, a water solution containing vegetal proteins as surfactants. In the third method, a combination of these two methods was employed. The foamed systems were consolidated for 24 hours at 40°C and then characterized by FTIR, X-Ray diffraction, scanning electron microscopy (SEM) and compression tests. Low density foams (∼500 Kg/m{sup 3}) with good cellular structure and mechanical properties were obtained by combining the “meringue” approach with the use of the chemical blowing agent based on Si.

  8. Effect of aluminosilicates and bentonite on aflatoxin-induced developmental toxicity in rat.

    PubMed

    Abdel-Wahhab, M A; Nada, S A; Amra, H A

    1999-01-01

    Numerous studies have established that aflatoxin is a potent developmental toxin in animals. Previous research has demonstrated that a phyllosilicate clay, hydrated sodium calcium aluminosilicate (HSCAS or Novasil), tightly binds and immobilizes aflatoxins in the gastrointestinal tract of animals and markedly reduces the bioavailability and toxicity of aflatoxin. Our objective in this study was to utilize the pregnant rat as an in vivo model to compare the potential of HSCAS and bentonite to prevent the developmental toxicity of aflatoxin. Aluminosilicates (HSCAS) and bentonite were added to the diet at a level of 0.5% (w/w) and fed to the pregnant rat throughout pregnancy (i.e. days 0-20). Test animals were fed an aflatoxin-contaminated diet (2.5 mg kg(-1) diet) with or without sorbents during gestation days 6-15. Evaluations of toxicity were performed on day 20. These included maternal (mortality, body weights, feed intake and litter weights), developmental (embryonic resorptions and fetal body weights) and biochemical (ALT, AST and AP) evaluations. Sorbents alone were not toxic and aflatoxin alone resulted in significant maternal and developmental toxicity. Animals treated with phyllosilicate (plus aflatoxin) were comparable to controls following evaluations for resorptions, live fetuses and fetal body weights, as well as biochemical parameters. While bentonite plus aflatoxin resulted in significant reduction in fetal body weight, none of the fetuses from HSCAS or bentonite plus aflatoxin-treated groups had any gross, internal soft tissue or major skeletal malformations.

  9. Effect of water on the heat capacity of polymerized aluminosilicate glasses and melts

    NASA Astrophysics Data System (ADS)

    Bouhifd, M. Ali; Whittington, Alan; Roux, Jacques; Richet, Pascal

    2006-02-01

    The effect of water on heat capacity has been determined for four series of hydrated synthetic aluminosilicate glasses and supercooled liquids close to albite, phonolite, trachyte, and leucogranite compositions. Heat capacities were measured at atmospheric pressure by differential scanning calorimetry for water contents between 0 and 4.9 wt % from 300 K to about 100 K above the glass transition temperature ( Tg). The partial molar heat capacity of water in polymerized aluminosilicate glasses, which can be considered as independent of composition, is =-122.319+341.631×10-3T+63.4426×105/T2 (J/mol K). In liquids containing at least 1 wt % H 2O, the partial molar heat capacity of water is about 85 J/mol K. From speciation data, the effects of water as hydroxyl groups and as molecular water have tentatively been estimated, with partial molar heat capacities of 153 ± 18 and 41 ± 14 J/mol K, respectively. In all cases, water strongly increases the configurational heat capacity at Tg and exerts a marked depressing effect on Tg, in close agreement with the results of viscosity experiments on the same series of glasses. Consistent with the Adam and Gibbs theory of relaxation processes, the departure of the viscosity of hydrous melts from Arrhenian variations correlates with the magnitude of configurational heat capacities.

  10. Spectroscopic studies of aluminosilicate formation in tank waste simulants

    SciTech Connect

    Su, Y.; Wang, L.; Bunker, B.C.; Windisch, C.F.

    1997-12-31

    Aluminosilicates are one of the major class of species controlling the volume of radioactive high-level waste that will be produced from future remediation at Hanford site. Here the authors present studies of the phases and structures of aluminosilicates as a function of sludge composition using X-ray powder diffraction, solid state {sup 27}Al and {sup 29}Si NMR, and Raman spectroscopy. The results show that the content of NaNO{sub 3} in solution has significant effects on the nature of the insoluble aluminosilicate phases produced. It was found that regardless of the initial Si:Al ratio, nitrate cancrinite was the main phase formed in the solution with pH of 13.5 and 5 M NaNO{sub 3}. However, at lower NaNO{sub 3} concentration with initial Si:Al ratios of 1.1, 2.2, and 11.0 in the solutions, a range of aluminosilicate zeolites was produced with Si:Al ratios of 1.1, 1.3, and 1.5, respectively. Lowering the solution pH appears to promote the formation of amorphous aluminosilicates. The results presented here are important for the prediction of the solubility and dissolution rate of Al in tank wastes.

  11. Mesostructured silica and aluminosilicate carriers for oxytetracycline delivery systems.

    PubMed

    Berger, D; Nastase, S; Mitran, R A; Petrescu, M; Vasile, E; Matei, C; Negreanu-Pirjol, T

    2016-08-30

    Oxytetracycline delivery systems containing various MCM-type silica and aluminosilicate with different antibiotic content were developed in order to establish the influence of the support structural and textural properties and aluminum content on the drug release profile. The antibiotic molecules were loaded into the support mesochannels by incipient wetness impregnation method using a drug concentrated aqueous solution. The carriers and drug-loaded materials were investigated by small- and wide-angle XRD, FTIR spectroscopy, TEM and N2 adsorption-desorption isotherms. Faster release kinetics of oxytetracycline from uncalcined silica and aluminosilicate supports was observed, whereas higher drug content led to lower delivery rate. The presence of aluminum into the silica network also slowed down the release rate. The antimicrobial assays performed on Staphylococcus aureus clinical isolates showed that the oxytetracycline-loaded materials containing MCM-41-type mesoporous silica or aluminosilicate carriers inhibited the bacterial development. PMID:26861688

  12. Mesostructured silica and aluminosilicate carriers for oxytetracycline delivery systems.

    PubMed

    Berger, D; Nastase, S; Mitran, R A; Petrescu, M; Vasile, E; Matei, C; Negreanu-Pirjol, T

    2016-08-30

    Oxytetracycline delivery systems containing various MCM-type silica and aluminosilicate with different antibiotic content were developed in order to establish the influence of the support structural and textural properties and aluminum content on the drug release profile. The antibiotic molecules were loaded into the support mesochannels by incipient wetness impregnation method using a drug concentrated aqueous solution. The carriers and drug-loaded materials were investigated by small- and wide-angle XRD, FTIR spectroscopy, TEM and N2 adsorption-desorption isotherms. Faster release kinetics of oxytetracycline from uncalcined silica and aluminosilicate supports was observed, whereas higher drug content led to lower delivery rate. The presence of aluminum into the silica network also slowed down the release rate. The antimicrobial assays performed on Staphylococcus aureus clinical isolates showed that the oxytetracycline-loaded materials containing MCM-41-type mesoporous silica or aluminosilicate carriers inhibited the bacterial development.

  13. Nanoscale encapsulation: the structure of cations in hydrophobic microporous aluminosilicates

    SciTech Connect

    Wasserman, S.R.; Yuchs, S.E.; Giaquinta, D.; Soderholm, L.; Song, Kang

    1996-10-01

    Hydrophobic microporous aluminosilicates, created by organic surface modification of inherently hydrophilic materials such as zeolites and clays, are currently being investigated as storage media for hazardous cations. Use of organic monolayers to modify the surface of an aluminosilicate after introducing an ion into the zeolite/clay reduces the interaction of water with the material. Resulting systems are about 20 times more resistant to leaching of stored ion. XAS spectra from the encapsulated ion demonstrate that byproducts from the organic modifier can complex with the stored cation. This complexation can result in a decreased affinity of the cation for the aluminosilicate matrix. Changing the organic modifier eliminates this problem. XAS spectra also indicate that the reactivity and speciation of the encapsulated ion may change upon application of the hydrophobic layer.

  14. Aluminosilicate and aluminosilicate based polymer composites: Present status, applications and future trends

    NASA Astrophysics Data System (ADS)

    Lopes, A. C.; Martins, P.; Lanceros-Mendez, S.

    2014-08-01

    Aluminosilicates have traditionally been important materials for applications related to adsorbents, water softeners, catalysis and mechanical and thermal reinforcement due to their high surface area, excellent thermal/hydrothermal stability, high shape-selectivity and superior ion-exchange ability. Recently, their use as polymer fillers has allowed to increasingly extending their application range to innovative areas such as medical and biological fields as well as in sensors, filtration membranes, energy storage and novel catalysis routes. Further, the large versatility and tailoring possibilities of both filler and matrix indicates this area as one of the enabling key technologies of the near future. This work summarizes the main developments up to date in this increasingly interesting field, focuses on the main applications already developed as well as on the key challenges for the near future.

  15. Recycling of aluminosilicate waste: Impact onto geopolymer formation

    NASA Astrophysics Data System (ADS)

    Essaidi, N.; Gharzouni, A.; Vidal, L.; Gouny, F.; Joussein, E.; Rossignol, S.

    2015-07-01

    Geopolymers are innovative ecomaterials resulting from the activation of an aluminosilicate source by an alkaline solution. Their properties depend on the used raw materials. This paper focuses on the possibility to obtain geopolymer materials with aluminosilicate laboratory waste. The effect of these additions on the geopolymer properties was studied by FTIR spectroscopy and mechanical test. It was evidenced a slowdown of the polycondensation reaction as well as the compressive strength due to the addition of laboratory waste which decreases the Si/K ratio of mixture.

  16. Modelling studies of water in crystalline nanoporous aluminosilicates.

    PubMed

    Bougeard, Daniel; Smirnov, Konstantin S

    2007-01-14

    The paper presents a review of molecular modelling studies of hydrated nanoporous aluminosilicates (zeolites and clays) performed during the last decade. A special emphasis is set on the calculation of the dynamical quantities and collective properties of the confined water. Some new results concerning the behaviour of water molecules in the siliceous silicalite and zeolite beta structures are presented.

  17. 27Al-->1H cross-polarization in aluminosilicates.

    PubMed

    Kolodziejski, W; Corma, A

    1994-06-01

    Solid-state nuclear magnetic resonance (NMR) cross-polarization (CP) from 27Al to 1H was set on kaolinite, verified by a variable-contact time experiment and applied to ultrastable zeolite Y. The technique is useful for the selective NMR observation of AlOH sites in aluminosilicates, especially those from extraframework species in zeolites.

  18. Enhancement of ion mobility in aluminosilicate-polyphosphazene nanocomposites

    SciTech Connect

    Hutchison, J.C.; Bissessur, R.; Shriver, D.F.

    1997-09-01

    Nanocomposites of poly(bis-(2(2-methoxyethoxy)ethoxy)phosphazene) (MEEP) or cryptand[2.2.2] with the aluminosilicate Na-montmorillonite (NaMont) were studied to develop new solid electrolytes with high conductivity and a unity cation transport number. An aluminosilicate was chosen because the low basicity of the Si-O-Al framework should minimize ion pairing. To further reduce ion pairing, solvating molecules or polymers such as cryptand[2.2.2] or MEEP were introduced into the aluminosilicate. When compared to pristine Na-montmorillonite, impedance spectroscopy indicates an increase in conductivity of up to 100 for MEEP{center_dot}NaMont intercalates, and of 50 for cryptand[2.2.2]{center_dot}NaMont intercalates. The MEEP{center_dot}NaMont intercalate exhibits high ionic conductivity anisotropy with respect to the montmorillonite layers ({sigma}{sub para.}/{sigma}{sub perp.} = 100), which is consistent with increased tortuosity of the cation diffusion path perpendicular to the structure layers. The temperature dependence of the conductivity suggests that cation transport is coupled to segmental motion of the intercalated polymer, as observed previously for simple polymer-salt complexes. Nanocomposites of solvating polymers or molecules with aluminosilicates provide a promising new direction in solid-state electrolytes.

  19. Topographical localization of the C-terminal region of the voltage-dependent sodium channel from Electrophorus electricus using antibodies raised against a synthetic peptide

    SciTech Connect

    Gordon, R.D.; Fieles, W.E.; Schotland, D.L.; Hogue-Angeletti, R.; Barchi, R.L.

    1987-01-01

    A peptide corresponding to amino acid residues 1783-1794 near the C terminus of the electric eel sodium channel primary sequence of the eel (Electrophorus electricus) sodium channel has been synthesized and used to raise an antiserum in rabbits. This antiserum specifically recognized the peptide in a solid-phase radioimmunoassay. Specificity of the antiserum for the native channel protein was shown by its specific binding to a 280-kDa protein in immunoblots of eel electroplax membrane proteins. The antiserum also specifically labeled the innervated membrane of the eel electroplax in immunofluorescent studies. The membrane topology of the peptide recognized by this antiserum was proved in binding studies using oriented electroplax membrane vesicles. These vesicles were 98% right-side-out as determined by (/sup 3/H)saxitoxin binding. Binding of the antipeptide antiserum to this fraction was measured before and after permeabilization with 0.01% saponin. Specific binding to intact vesicles was low, but this binding increased 10-fold after permeabilization, implying a cytoplasmic orientation for the peptide. Confirmation for this orientation was then sought by localizing the antibody bound to intact electroplax cells with immunogold electron microscopy. The data imply that the region of the sodium channel primary sequence near the C terminus that is recognized by the anitserum is localized on the cytoplasmic side of the membrane; this localization provides some further constraints on models of sodium channel tertiary structure.

  20. Transformation of Aluminosilicate Wet Gel to Solid State

    NASA Astrophysics Data System (ADS)

    Sinkó, Katalin; Pöppl, László

    2002-04-01

    Optically clear, homogeneous, monolithic aluminosilicate gels were prepared directly from solutions of inorganic aluminum salt, tetraethoxysilane, and alcohol. The dried aluminosilicate gels show new special properties, e.g. piezoelectricity and variable porosity (1-2000 m 2/g) due to the fractal-like gel structure. Ceramic products, which keep the chemical bonds and structure of the gels, were produced by heat treatment at 300-350°C. The processes that occurred during heat treatment were investigated by thermal analysis and mass spectrometry. The temperature limits of the gel state were determined by differential scanning calorimetry and small angle X-ray scattering. The collapse of the gel structure began around 350°C; however, the amorphous character remained until the temperature (ca. 970°C) of the phase transmission.

  1. Aluminosilicates and senile plaque formation in Alzheimer's disease.

    PubMed

    Candy, J M; Oakley, A E; Klinowski, J; Carpenter, T A; Perry, R H; Atack, J R; Perry, E K; Blessed, G; Fairbairn, A; Edwardson, J A

    1986-02-15

    Aluminium and silicon were found to be colocalised in the central region of senile plaque cores in studies with energy dispersive X-ray microanalysis. The distribution of these elements was similar in cores isolated from the cerebral cortex of patients with senile dementia of the Alzheimer type and in cores studied in situ from tissue sections from the cerebral cortex of presenile and senile patients with Alzheimer's disease, and elderly, mentally normal patients. High-resolution solid-state nuclear magnetic resonance techniques showed aluminium and silicon to be present as aluminosilicates. The presence of aluminosilicates at the centre of senile plaque cores contrasts with the distribution of other inorganic constituents and suggests that they may be involved in the initiation or early stages of senile plaque formation.

  2. Mesoporous aluminosilicate ropes with improved stability from protozeolitic nanoclusters

    NASA Astrophysics Data System (ADS)

    Zheng, Junlin; Kong, Dejin; Yang, Weimin; Xie, Zaiku; Wu, Dong; Sun, Yuhan

    2007-02-01

    Mesoporous aluminosilicate ropes with improved hydrothermal stability have been prepared through S +X -I + route via self-assembly of protozeolitic nanoclusters with cetyltrimethylammonium bromides (CTAB) template micelles in HNO 3 solution. SEM observation confirmed that high-yield aluminosilicate ropes could be produced under proper HNO 3 concentration. NO 3- ions had strong binding strength to the CTA + ions and tended to form more elongated surfactant micelles, thus fibrous products were fabricated under the direction of these long rod micelles in shearing flow. At the same time, the NO 3- ions combining with CTA + ions generated more active (CTA +NO 3-) assembly, which effectively catalysed the polymerization of protozeolitic nanoclusters with large volume into highly ordered mesostructures. Compared with normal MCM-41 silica synthesized through S +X -I + route in acidic media, the hydrothermal stability was improved considerably. These protozeolitic nanoclusters survived strongly acidic media and entered into mesostructured framework, which contributed to the improvement of hydrothermal stability.

  3. Channel waveguides in glass via silver-sodium field-assisted ion exchange

    NASA Technical Reports Server (NTRS)

    Forrest, K.; Pagano, S. J.; Viehmann, W.

    1986-01-01

    Multimode channel waveguides have been formed in sodium aluminosilicate glass by field-assisted diffusion of Ag(+) ions from vacuum-evaporated Ag films. The two-dimensional refractive index profiles of the waveguides were controlled by varying the diffusion time, the diffusion temperature, and the electric field strength. Estimates of the diffusion rate through a strip aperture were obtained, assuming the electric field was strong 120-240 V/mm. The maximum change in refractive index in the sodium aluminosilicate glasses was estimated near 65 percent of the change in soda-lime silicate glass. The physical properties of the glasses are given in a table.

  4. Hard x-ray nanotomography of amorphous aluminosilicate cements.

    SciTech Connect

    Provis, J. L.; Rose, V.; Winarski, R. P.; van Deventer, J. S. J.

    2011-08-01

    Nanotomographic reconstruction of a sample of low-CO{sub 2} 'geopolymer' cement provides the first three-dimensional view of the pore structure of the aluminosilicate geopolymer gel, as well as evidence for direct binding of geopolymer gel onto unreacted fly ash precursor particles. This is central to understanding and optimizing the durability of concretes made using this new class of binder, and demonstrates the value of nanotomography in providing a three-dimensional view of nanoporous inorganic materials.

  5. Mesoporous aluminosilicate ropes with improved stability from protozeolitic nanoclusters

    SciTech Connect

    Zheng Junlin; Kong Dejin; Yang Weimin; Xie Zaiku; Wu Dong; Sun Yuhan

    2007-02-15

    Mesoporous aluminosilicate ropes with improved hydrothermal stability have been prepared through S{sup +}X{sup -}I{sup +} route via self-assembly of protozeolitic nanoclusters with cetyltrimethylammonium bromides (CTAB) template micelles in HNO{sub 3} solution. SEM observation confirmed that high-yield aluminosilicate ropes could be produced under proper HNO{sub 3} concentration. NO{sub 3} {sup -} ions had strong binding strength to the CTA{sup +} ions and tended to form more elongated surfactant micelles, thus fibrous products were fabricated under the direction of these long rod micelles in shearing flow. At the same time, the NO{sub 3} {sup -} ions combining with CTA{sup +} ions generated more active (CTA{sup +}NO{sub 3} {sup -}) assembly, which effectively catalysed the polymerization of protozeolitic nanoclusters with large volume into highly ordered mesostructures. Compared with normal MCM-41 silica synthesized through S{sup +}X{sup -}I{sup +} route in acidic media, the hydrothermal stability was improved considerably. These protozeolitic nanoclusters survived strongly acidic media and entered into mesostructured framework, which contributed to the improvement of hydrothermal stability. - Graphical abstract: Mesoporous aluminosilicate ropes with enhanced hydrothermal stability were fabricated from protozeolitic nanoclusters through S{sup +}X{sup -}I{sup +} route in HNO{sub 3} solution under the direction of CTAB templates.

  6. Development of Li+ alumino-silicate ion source

    SciTech Connect

    Roy, P.K.; Seidl, P.A.; Waldron, W.; Greenway, W.; Lidia, S.; Anders, A.; Kwan, J.

    2009-04-21

    To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, one strategy is to deposit most of the ion energy at the peak of energy loss (dE/dx) with a low (E< 5 MeV) kinetic energy beam and a thin target[1]. Lower mass ions have a peak dE/dx at a lower kinetic energy. To this end, a small lithium (Li+) alumino-silicate source has been fabricated, and its emission limit has been measured. These surface ionization sources are heated to 1000-1150 C where they preferentially emit singly ionized alkali ions. Alumino-silicates sources of K+ and Cs+ have been used extensively in beam experiments, but there are additional challenges for the preparation of high-quality Li+ sources: There are tighter tolerances in preparing and sintering the alumino-silicate to the substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. We report on recent measurements ofhigh ( up to 35 mA/cm2) current density from a Li+ source. Ion species identification of possible contaminants is being verified with a Wien (E x B) filter, and via time-of-flight.

  7. Relationship between texture and acidic properties of aluminosilicates and the conditions of their preparation

    SciTech Connect

    Grzechowiak, E.R.; Masalska, A.

    1986-04-01

    A study has been made of the method of pH adjustment in the precipitation of hydrogel in relation to its influence on the texture and acidic properties of alumino-silicates. It has been established that large-pore aluminosilicates can be obtained from neutral solutions. X-ray diffraction analysis of aluminosilicates has shown that the method of pH adjustment also affects their phase composition.

  8. Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study.

    SciTech Connect

    Davis, Linda L.; Darab, John G.; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S.; Li, Hong; Strachan, Denis M.; Li, Liyu

    2003-10-15

    A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others.

  9. Characterisation of frequency doubling in Eu(2+) doped aluminosilicate fibres

    NASA Technical Reports Server (NTRS)

    Driscoll, T. J.; Lawandy, N. M.; Killian, A.; Rienhart, L.; Morse, T. F.

    1991-01-01

    The results of a series of experiments on efficient second-harmonic generation in a fiber with a Eu(2+)-doped aluminosilicate core are reported. The fiber was prepared by the seeding method with CW mode-locked radiation at 1.06 micron and produced ultrastable peak conversion efficiencies of 0.001 during mode-locked readout. Experiments were performed to determine the IR preparation intensity dependence, the stability of the output, and the type of erasure mechanisms which occur. The results are compared with those of germanosilicate fibers and some similarities and differences are discussed.

  10. Relation of the acidity of amorphous aluminosilicates with their activity and selectivity in isomerization of xylenes

    SciTech Connect

    Zadymov, V.V.; Lupina, M.I.; Kaliko, M.A.

    1981-01-01

    Conversion of m-xylene on amorphous aluminosilicates is determined by overall surface acidity. The formation of acid centres with pK a greater than or equal toapprox. =-10 as a result of heat-steam treatment of aluminosilicates and a reduction in the number of strong centres increases selectivity in isomerization of m-xylene.

  11. The kinetics of desilication of synthetic spent Bayer liquor seeded with cancrinite and cancrinite/sodalite mixed-phase crystals

    NASA Astrophysics Data System (ADS)

    Barnes, Mark C.; Addai-Mensah, Jonas; Gerson, Andrea R.

    1999-04-01

    Isothermal, batch desilication kinetics of synthetic, sodium aluminate solution (spent Bayer liquor) via cancrinite and cancrinite/sodalite mixed-phase crystal growth, have been studied under conditions at which sodium aluminosilicate scale forms at the surfaces of steel heat exchangers of alumina plant. Seeding with the pure cancrinite and mixed-phase crystals results in the suppression of scale formation and a faster rate of liquor desilication in comparison with its sodalite dimorph. Cancrinite seed crystals prepared from NO -3-rich solutions exhibited crystal growth mechanism and kinetic behaviour different from dimorphic mixed-phase crystals prepared from CO 2-3-rich solutions, when both were used to desilicate CO 2-3-rich spent Bayer liquor. The rate of desilication due to crystal growth on CO 2-3-cancrinite/sodalite mixed phase crystals followed a second-order dependence on the relative supersaturation of SiO 2. An activation energy of 52 kJ mol -1 was estimated for the crystal growth process. For desilication kinetics involving NO -3-cancrinite seed crystal growth, a third-order dependence on relative supersaturation of SiO 2 and an activation energy of 63 kJ mol -1 were obtained.

  12. Microstructural and phase evolution in metakaolin geopolymers with different activators and added aluminosilicate fillers

    NASA Astrophysics Data System (ADS)

    Sarkar, Madhuchhanda; Dana, Kausik; Das, Sukhen

    2015-10-01

    This work aims to investigate the microstructural and phase evolution of alkali activated metakaolin products with different activators and added aluminosilicate filler phases. The added filler phases have different reactivity to the alkali activated metakaolin system. Microstructural evolution in the alkali activated products has been investigated by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscope (FESEM). Variation in strength development in alkali activated metakaolin products was followed by compressive strength measurement test. Microstructural study shows that in case of metakaolin with NaOH activator crystalline sodalite formed in all the product samples irrespective of the added filler phases. The microstructure of these NaOH activated products investigated by FESEM showed crystalline and inhomogeneous morphology. Mixed activator containing both NaOH and sodium silicate in a fixed mass ratio formed predominantly amorphous phase. Microstructure of these samples showed more homogeneity than that of NaOH activated metakaolin products. The study further shows that addition of α-Al2O3 powder, non reactive phase to the alkali activated metakaolin system when used in larger amount increased crystalline phase in the matrix. α-Al2O3 powder addition increased the compressive strength of the product samples for both the activator compositions. Added phase of colloidal silica, reactive to the alkali activated metakaolin system when used in larger amount was found to increase amorphous nature of the matrix. Addition of colloidal silica influenced the compressive strength property differently with different activator compositions.

  13. Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

    SciTech Connect

    Ruiz-Santaquiteria, C.; Fernandez-Jimenez, A.; Palomo, A.

    2012-09-15

    This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

  14. Mesoporous aluminosilicates assembled from dissolved LTA zeolite and triblock copolymer in the presence of tetramethylammonium hydroxide.

    PubMed

    Tanaka, Shunsuke; Okada, Hiroaki; Nakatani, Norihito; Maruo, Takanori; Nishiyama, Norikazu; Miyake, Yoshikazu

    2009-05-15

    Zeolite Na-A crystals dissolved in a HCl solution were used as a single-source of silicon and aluminum for the synthesis of mesoporous aluminosilicates via a template-assisted method with an organic base tetramethylammonium hydroxide (TMAOH). Amphiphilic triblock copolymer Pluronic F127 (EO(106)PO(70)EO(106)) was used as template. Increasing the amount of TMAOH in the synthetic solution resulted in an increase in the aluminum content of the products. On the other hand, mesostructural periodicity was deteriorated with higher content of aluminum incorporated into the mesoporous framework. The samples with low Si/Al ratios less than 5 have wormhole-like pore structure, while the samples with Si/Al ratios more than 7 possess highly ordered mesoporous structure, a body-centered Im3m symmetry, with single crystal like morphology. The samples with Si/Al ratio of 7, which prepared at TMAOH molar concentration of 25 mM in the templating solution, possess BET surface area of 470 m(2)/g, pore size of 6.4 nm, and pore volume of 0.56 cm(3)/g. Aluminum atoms have successfully been incorporated in a tetra-coordinated position and remained stable even after calcination at 600 degrees C.

  15. Alumino-silicate ion sources for accelerator applications

    SciTech Connect

    Warwick, A.I.

    1985-04-01

    As part of the program of Heavy Ion Fusion Accelerator Research at the Lawrence Berkeley Laboratory, ion sources have been developed using thermionic emitters of singly charged alkali metal ions. These emitters are flat surfaces of alumino-silicate, loaded with the appropriate ion. They have become convenient and reliable sources producing pulsed beams of very low emittance. Thermionic emission of ions from alumino-silicates has been known for a very long time. Here the author focuses on the practical application as accelerator ion sources. The author discusses the fabrication and heating of large area emitters, uniformity of emission and the maximum ion current density which can be extracted under space charge limited conditions, with zero electric field on the emitter surface. Results are presented for Na, K and Cs ions showing maximum space charge limited current densities of 25, 40 and 120 mAcm/sup -2/ respectively. In the case of cesium the author has produced a 5 mA beam at a kinetic energy of 200 keV with normalized emittance 1.2 x 10/sup -7/ ..pi.. m rad.

  16. Effective Sequestration of Clostridium difficile Protein Toxins by Calcium Aluminosilicate.

    PubMed

    Sturino, Joseph M; Pokusaeva, Karina; Carpenter, Robert

    2015-12-01

    Clostridium difficile is a leading cause of antibiotic-associated diarrhea and the etiologic agent responsible for C. difficile infection. Toxin A (TcdA) and toxin B (TcdB) are nearly indispensable virulence factors for Clostridium difficile pathogenesis. Given the toxin-centric mechanism by which C. difficile pathogenesis occurs, the selective sequestration with neutralization of TcdA and TcdB by nonantibiotic agents represents a novel mode of action to prevent or treat C. difficile-associated disease. In this preclinical study, we used quantitative enzyme immunoassays to determine the extent by which a novel drug, calcium aluminosilicate uniform particle size nonswelling M-1 (CAS UPSN M-1), is capable of sequestering TcdA and TcdB in vitro. The following major findings were derived from the present study. First, we show that CAS UPSN M-1 efficiently sequestered both TcdA and TcdB to undetectable levels. Second, we show that CAS UPSN M-1's affinity for TcdA is greater than its affinity for TcdB. Last, we show that CAS UPSN M-1 exhibited limited binding affinity for nontarget proteins. Taken together, these results suggest that ingestion of calcium aluminosilicate might protect gastrointestinal tissues from antibiotic- or chemotherapy-induced C. difficile infection by neutralizing the cytotoxic and proinflammatory effects of luminal TcdA and TcdB.

  17. The aluminum ordering in aluminosilicates: a dipolar 27Al NMR spectroscopy study.

    PubMed

    Gee, Becky A

    2004-01-01

    The spatial ordering of aluminum atoms in CsAl(SiO3)2 and 3Al2O3.2SiO2 was probed by 27Al dipolar solid-state NMR spectroscopy. The 27Al response to a Hahn spin-echo pulse sequence in a series of aluminum-containing model crystalline compounds demonstrates that quantitative 27Al homonuclear dipolar second moments can be obtained to within +/-20% of the theoretical values, if evaluation of the spin-echo response curve is limited to short evolution periods (2t1 < or = 0.10 ms). Additionally, selective excitation of the central transition m = 1/2 --> -1/2 is necessary in order to ensure quantitative results. Restriction of spin exchange affecting the dephasing of the magnetization may decelerate the spin-echo decay at longer evolution periods. Considering these restraints, the method was used to probe the spatial distribution of aluminum atoms among the tetrahedral sites in two aluminosilicate materials. Experimental 27Al spin-echo response data for the aluminosilicates CsAl(SiO3)2 (synthetic pollucite) and 3Al2O3.2SiO2 (mullite) are compared with theoretical data based on (I) various degrees of aluminum-oxygen-aluminum bond formation among tetrahedrally coordinated aluminum atoms (Al(T(d) )-O-Al(T(d) )) and (II) the maximum avoidance of Al(T(d) )-O-Al(T(d) ) bonding. Analysis of the second moment values and resulting echo decay responses suggests that partial suppression of spin exchange among aluminum atoms in crystallographically distinct sites may contribute to the 27Al spin echo decay in 3Al2O3.2SiO2, thus complicating quantitative analysis of the data. Silicon-29 and aluminum-27 magic angle spinning (MAS) NMR spectra of 3Al2O3.2SiO2 are consistent with those previously reported. The experimental 27Al spin-echo response behavior of CsAl(SiO3)2 differs from the theoretical response behavior based on the maximum avoidance of Al-O-Al bonding between tetrahedral aluminum sites in CsAl(SiO3)2. A single unresolved resonance is observed in both the silicon-29 and

  18. 21 CFR 184.1754 - Sodium diacetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Reg. No. 126-96-5) is a molecular compound of acetic acid, sodium acetate, and water of hydration. The technical grade is prepared synthetically by reacting sodium carbonate with acetic acid. Special grades are produced by reacting anhydrous sodium acetate and acetic acid. (b) The ingredient meets the...

  19. Analysis of aluminosilicate particles in biological matrices using histochemistry and X-ray microanalysis.

    PubMed

    Powell, J J

    2002-06-01

    Aluminosilicates are a group of ubiquitous environmental particles that, in some cases, have been implicated in human disease. Characterisation of aluminosilicates in tissue samples requires, first, their in situ identification and, secondly, analysis of their aluminium and silicon content or, at least, aluminium:silicon ratio. Here, histochemical staining, microscopy and X-ray microanalysis were investigated as potential methods for the detection of aluminosilicates in biological samples. In contrast to aluminium phosphate or hydroxide, aluminosilicates were refractory to histochemical staining for aluminium. However, using electron microscopy, back scattered electrons allowed identification of aluminosilicates in tissue-like (gelatine) sections. X-ray microanalysis, using conventional peak:background ratios, did not provide a sufficiently accurate assessment of the aluminium content of various standard aluminosilicates to allow their identification. However, the similar spectral energies of aluminium and silicon allowed spectral peak heights to be directly compared and, using simple standards, aluminium:silicon ratios were found for a range of reference particles. Application of this technique should allow the localisation and identification of aluminosilicates in biological samples.

  20. Sodium Bicarbonate

    MedlinePlus

    ... pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking sodium bicarbonate, call your doctor. ... your body. If you are on a sodium-restricted diet, check with your doctor before taking sodium bicarbonate.

  1. Dynamic Reduction of FeO-Bearing, Anhydrous Aluminosilicate Melts

    NASA Astrophysics Data System (ADS)

    Everman, R. L.; Cooper, R. F.

    2004-12-01

    We have studied the reduction dynamics of FeO-bearing aluminosilicate melts at oxygen activities sufficiently low to form metallic iron. The experiments involved reacting droplets, suspended from refractory metal wires, with a high-temperature ( ˜1400oC), controlled-oxygen-activity environment maintained by a dynamic CO:CO2 buffer. In the case of an FeO-doped magnesium aluminosilicate ("Fe-MAS") melt ( ˜5 mol% FeO) exposed to an oxygen activity of 2x10-13 ("QIF-2"; CO:CO2=240:1), the reduction dynamic is rate-limited by chemical diffusion of Mg2+: oxygen chemically ablates from the free surface and the network-modifying cations diffuse inward, charge-compensated by a counterflux of electron holes (the "semiconductor condition" holds for diffusion dynamics in this melt [e.g., Cook and Cooper, 2000]); nm-scale crystals of pure α -Fe nucleate at an internal front. Diffusion of an oxygen species is not involved. In the case of FeO-doped calcium-magnesium aluminosilicate (Fe-CMAS) melt ( ˜8 mol% FeO) exposed to an oxygen activity of 2x10-15 (QIF-4; CO:CO2=1750:1), the dynamic changes: molten Fe-C-Si alloy droplets form near the surface, and bubbles are seen to form internally, truncating at an internal front. Further, the reaction occurs more slowly than that seen for the similarly polymerized Fe-MAS melt. The results suggests that molecular CO diffuses inward, consuming electron holes so as to form carbonate ion species in the melt [cf. Brooker et al., 2001]. Quenching produces a driving potential to reverse the internal reduction reaction, so creating the bubbles. Consumption of the electron holes by reaction with the carbon species dramatically reduces the reduction-to-metal kinetics. Brooker RA, Kohn SC, Holloway JR, McMillan PF (2001) Chem Geol 174:241-254; Cook GB, Cooper RF (2000) Am Mineral 85:397-406

  2. In situ Brillouin study of sodium alumino silicate glasses under pressure

    NASA Astrophysics Data System (ADS)

    Sonneville, C.; De Ligny, D.; Mermet, A.; Champagnon, B.; Martinet, C.; Henderson, G. H.; Deschamps, T.; Margueritat, J.; Barthel, E.

    2013-08-01

    The in situ elastic and plastic behaviors of sodium aluminosilicate glasses with different degrees of depolymerization were analyzed using Brillouin spectroscopy. The observed elastic anomaly progressively vanished with depolymerization. The densification process appears to be different from that observed in pure silica glass. In the plastic regime of densified glasses hysteresis loops were observed and related to modification of the local silicon environment facilitated by the addition of sodium.

  3. Crystallization Kinetics of Calcium-magnesium Aluminosilicate (CMAS) Glass

    NASA Technical Reports Server (NTRS)

    Wiesner, Valerie L.; Bansal, Narottam P.

    2015-01-01

    The crystallization kinetics of a calcium-magnesium aluminosilicate (CMAS) glass with composition relevant for aerospace applications, like air-breathing engines, were evaluated using differential thermal analysis (DTA) in powder and bulk forms. Activation energy and frequency factor values for crystallization of the glass were evaluated. X-ray diffraction (XRD) was used to investigate the onset of crystallization and the phases that developed after heat treating bulk glass at temperatures ranging from 690 to 960 deg for various times. Samples annealed at temperatures below 900 deg remained amorphous, while specimens heat treated at and above 900 deg exhibited crystallinity originating at the surface. The crystalline phases were identified as wollastonite (CaSiO3) and aluminum diopside (Ca(Mg,Al) (Si,Al)2O6). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to examine the microstructure and chemical compositions of crystalline phases formed after heat treatment.

  4. The aluminosilicate fraction of North Pacific manganese nodules

    USGS Publications Warehouse

    Bischoff, J.L.; Piper, D.Z.; Leong, K.

    1981-01-01

    Nine nodules collected from throughout the deep North Pacific were analyzed for their mineralogy and major-element composition before and after leaching with Chester-Hughes solution. Data indicate that the mineral phillipsite accounts for the major part (> 75%) of the aluminosilicate fraction of all nodules. It is suggested that formation of phillipsite takes place on growing nodule surfaces coupled with the oxidation of absorbed manganous ion. All the nodules could be described as ternary mixtures of amorphous iron fraction (Fe-Ti-P), manganese oxide fraction (Mn-Mg Cu-Ni), and phillipsite fraction (Al-Si-K-Na), these fractions accounting for 96% of the variability of the chemical composition. ?? 1981.

  5. Adsorption of β-galactosidase on silica and aluminosilicate adsorbents

    NASA Astrophysics Data System (ADS)

    Atyaksheva, L. F.; Dobryakova, I. V.; Pilipenko, O. S.

    2015-03-01

    It is shown that adsorption of β-galactosidase of Aspergillus oryzae fungi on mesoporous and biporous silica and aluminosilicate adsorbents and the rate of the process grow along with the diameter of the pores of the adsorbent. It is found that the shape of the adsorption isotherms changes as well, depending on the texture of the adsorbent: the Michaelis constant rises from 0.3 mM for the enzyme in solution to 0.4-0.5 mM for the enzyme on a surface in the hydrolysis of o-nitrophenyl-β-D-galactopyranoside. It is concluded that β-galactosidase displays its maximum activity on the surface of biporous adsorbents.

  6. 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.

  7. Synthetic carbonaceous fuels and feedstocks

    DOEpatents

    Steinberg, Meyer

    1980-01-01

    This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends. The oxygen generated at the anode is preferably vented into the atmosphere, and the regenerated sodium hydroxide produced at the cathode is reused for scrubbing the CO.sub.2 from the atmosphere.

  8. RESULTS OF CAUSTIC DISSOLUTION OF ALUMINOSILICATE SCALE AND CHARACTERIZATION DATA FOR SAMPLES FROM THE EVAPORATOR POT AND GRAVITY DRAIN LINE

    SciTech Connect

    Wilmarth, B; Rita Sullivan, R; Chris Martino, C

    2006-08-21

    The build-up of sodium aluminosilicate scale in the 2H Evaporator system continues to cause operational difficulties. The use of a nitric acid cleaning operation proved successful in 2001. However, the operation required additional facilities to support spent cleaning solution neutralization and was quite costly. A proposed caustic cleaning flowsheet has many advantages over the acid flowsheet. Therefore, samples were retrieved from the evaporator system (gravity drain line and pot) for both chemical and radiological characterization and dissolution testing. The characterization of these scale samples showed the presence of nitrated cancrinite along with a dehydrated zeolite. Small amounts of depleted uranium were also found in these samples as expected and the amount of uranium ranged from 0.5 wt% to 2 wt%. Dissolution in sodium hydroxide solutions of various caustic concentrations showed that the scale slowly dissolves at elevated temperature (90 C). Data from similar testing indicate that the scale removed from the GDL in 2005 dissolves slower than that removed in 1997. Differences in the particle size of these samples of scale may well explain the measured dissolution rate differences.

  9. Effects of Anions on Local Structure of Al and Si in Aluminosilicates.

    PubMed

    Miyazaki; Yokoyama

    1999-06-15

    Three kinds of amorphous aluminosilicates were synthesized by coprecipitation of silicic acid with aluminum hydroxide in the presence of different inorganic ions: sulfate, chloride, and nitrate. Although the bulk composition of the aluminosilicates obtained was not affected by anion species, their DTA spectra were significantly different, suggesting that their structures also differ. The local structure of Al and Si in the aluminosilicates was studied in detail by 27Al and 29Si MAS NMR. From the 27Al MAS NMR spectra and comparison between 29Si HD- and CP-MAS NMR spectra, it was concluded that the aluminosilicate obtained in the presence of sulfate ions has only a montmorillonite-like structure, whereas in the cases of chloride and nitrate, the solids are composed of three phases: aluminum hydroxide, silica, and the montmorillonite-like aluminosilicate. The difference in the local structure of Al and Si in the aluminosilicates was explained by the difference in interaction between the anions and aluminum ions. Copyright 1999 Academic Press.

  10. Effects of anions on local structure of Al and Si in aluminosilicates

    SciTech Connect

    Miyazaki, Akane; Yokoyama, Takushi

    1999-06-15

    Three kinds of amorphous aluminosilicates were synthesized by coprecipitation of silicic acid with aluminum hydroxide in the presence of different inorganic ions: sulfate, chloride, and nitrate. Although the bulk composition of the aluminosilicates obtained was not affected by anion species, their DTA spectra were significantly different, suggesting that their structures also differ. The local structure of Al and Si in the aluminosilicates was studied in detail by {sup 27}Al and {sup 29}Si MAS NMR. From the {sup 27}Al MAS NMR spectra and comparison between {sup 29}Si HD- and CP-MAS NMR spectra, it was concluded that the aluminosilicate obtained in the presence of sulfate ions has only a montmorillonite-like structure, whereas in the cases of chloride and nitrate, the solids are composed of three phases: aluminum hydroxide, silica, and the montmorillonite-like aluminosilicate. The difference in the local structure of Al and Si in the aluminosilicates was explained by the difference in interaction between the anions and aluminum ions.

  11. Analysis of the biological and chemical reactivity of zeolite-based aluminosilicate fibers and particulates.

    PubMed Central

    Fach, Estelle; Waldman, W James; Williams, Marshall; Long, John; Meister, Richard K; Dutta, Prabir K

    2002-01-01

    Environmental and/or occupational exposure to minerals, metals, and fibers can cause lung diseases that may develop years after exposure to the agents. The presence of toxic fibers such as asbestos in the environment plus the continuing development of new mineral or vitreous fibers requires a better understanding of the specific physical and chemical features of fibers/particles responsible for bioactivity. Toward that goal, we have tested aluminosilicate zeolites to establish biological and chemical structure-function correlations. Zeolites have known crystal structure, are subject to experimental manipulation, and can be synthesized and controlled to produce particles of selected size and shape. Naturally occurring zeolites include forms whose biological activity is reported to range from highly pathogenic (erionite) to essentially benign (mordenite). Thus, we used naturally occurring erionite and mordenite as well as an extensively studied synthetic zeolite based on faujasite (zeolite Y). Bioactivity was evaluated using lung macrophages of rat origin (cell line NR8383). Our objective was to quantitatively determine the biological response upon interaction of the test particulates/fibers with lung macrophages and to evaluate the efficacy of surface iron on the zeolites to promote the Fenton reaction. The biological assessment included measurement of the reactive oxygen species by flow cytometry and chemiluminescence techniques upon phagocytosis of the minerals. The chemical assessment included measuring the hydroxyl radicals generated from hydrogen peroxide by iron bound to the zeolite particles and fibers (Fenton reaction). Chromatography as well as absorption spectroscopy were used to quantitate the hydroxyl radicals. We found that upon exposure to the same mass of a specific type of particulate, the oxidative burst increased with decreasing particle size, but remained relatively independent of zeolite composition. On the other hand, the Fenton reaction

  12. IR and XPS study of NO and CO interaction with palladium catalysts supported on aluminosilicates

    SciTech Connect

    Venezia, A.M.; Liotta, L.F.; Deganello, G. |; Terreros, P.; Pena, M.A.; Fierro, J.L.G.

    1999-02-16

    Adsorption of CO and NO individually and as a mixture of both on palladium catalysts has been investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The effect of sodium ions has been considered by comparing Pd/SiO{sub 2} catalyst, sodium-doped Pd/SiO{sub 2}, and Pd on natural and synthetic silicoaluminates containing sodium in their bulk structure but differing in the surface area of the support. The presence of sodium induces a different adsorption behavior depending on its location, either at the surface of the catalysts or inside the support structure. As a consequence, different species are formed from the reaction between NO and CO at room temperature and at high temperature. Modification of the metal surface of the various catalysts is observed upon the gas treatments. Palladium is oxidized to a certain extent depending on the type of the catalyst support. Moreover, different chemical states of the adsorbed nitrogen species are found.

  13. The metapelitic garnet biotite muscovite aluminosilicate quartz (GBMAQ) geobarometer

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Ming; Zhao, Guochun C.

    2007-09-01

    In this contribution we have empirically calibrated the garnet-biotite-muscovite-aluminosilicate-quartz (GBMAQ) barometer using low- to medium-high-pressure, mid-grade metapelites. Application of the barometer suggests that the GBMAQ and GASP barometers show quite similar pressure estimates. Furthermore, metapelites within thermal contact aureole or very limited geographic area show no meaningful pressure diversity determined by the GBMAQ and GASP barometers which is the geological reality. The random error of the GBMAQ barometer is expected to be around ± 0.8 kbar, and this barometer shows no systematic bias with respect to either pressure, or temperature, or Al VI in muscovite, or Fe in biotite, or Fe in garnet. The GBMAQ barometer is thermodynamically consistent with the garnet-biotite geothermometer because they share the same activity models of both garnet and biotite. This barometer is especially useful for assemblages with Ca-poor garnet or Ca-poor plagioclase or plagioclase-absent metapelites. Application of this barometer beyond the calibration ranges, i.e., P- T range and chemical ranges of the minerals, is not encouraged.

  14. Electro-optical parameters of bond polarizability model for aluminosilicates.

    PubMed

    Smirnov, Konstantin S; Bougeard, Daniel; Tandon, Poonam

    2006-04-01

    Electro-optical parameters (EOPs) of bond polarizability model (BPM) for aluminosilicate structures were derived from quantum-chemical DFT calculations of molecular models. The tensor of molecular polarizability and the derivatives of the tensor with respect to the bond length are well reproduced with the BPM, and the EOPs obtained are in a fair agreement with available experimental data. The parameters derived were found to be transferable to larger molecules. This finding suggests that the procedure used can be applied to systems with partially ionic chemical bonds. The transferability of the parameters to periodic systems was tested in molecular dynamics simulation of the polarized Raman spectra of alpha-quartz. It appeared that the molecular Si-O bond EOPs failed to reproduce the intensity of peaks in the spectra. This limitation is due to large values of the longitudinal components of the bond polarizability and its derivative found in the molecular calculations as compared to those obtained from periodic DFT calculations of crystalline silica polymorphs by Umari et al. (Phys. Rev. B 2001, 63, 094305). It is supposed that the electric field of the solid is responsible for the difference of the parameters. Nevertheless, the EOPs obtained can be used as an initial set of parameters for calculations of polarizability related characteristics of relevant systems in the framework of BPM.

  15. Ageing characteristics of aluminium alloy aluminosilicate discontinuous fiber reinforced composites

    SciTech Connect

    Nath, D.; Singh, V.

    1999-03-05

    Development of continuous fiber reinforced metal matrix composites is aimed at providing high specific strength and stiffness needed for aerospace and some critical high temperature structural applications. Considerable efforts have been made, during the last decade, to improve the strength of age-hardening aluminium alloy matrix composites by suitable heat treatment. It has also been well established that age-hardenable aluminium alloy composites show accelerated ageing behavior because of enhanced dislocation density at the fiber/matrix interface resulting from thermal expansion mismatch between ceramic fiber and the metal matrix. The accelerated ageing of aluminium alloy composites either from dislocation density or the residual stress, as a result of thermal expansion mismatch is dependent on the size of whisker and particulate. Investigations have also been made on the effect of volume fraction of particulate on the ageing behavior of aluminium alloys. The present investigation is concerned with characterization of age-hardening behavior of an Al-Si-Cu-Mg(AA 336) alloy alumino-silicate discontinuous fiber-reinforced composites (referred to as aluminium MMCs in the present text) being developed for automotive pistons. An effort is made to study the effect of volume fraction of the reinforcement on age-hardening behavior of this composite.

  16. A new SiC-whisker-reinforced lithium aluminosilicate composite

    SciTech Connect

    Xue, L.A.; Chen, Iwei . Dept. of Materials Science and Engineering)

    1993-11-01

    The glass-ceramic matrix of the well-known lithium aluminosilicate (LAS)/SiC composite is usually formulated near the spodumene composition. The authors report a new composition which is rich in alumina and lean in silica and lithia. This formulation offers a new option of converting the glass-ceramic matrix to a mullite/alumina matrix upon annealing above 1,400 C, and hence better creep resistance and other high-temperature mechanical properties. Using a transient-phase processing method that they developed previously for the superplastic forming of mullite, the authors are able to hot-press a composite containing 30 vol% SiC whiskers at [approximately]1,350 C to achieve full density. Flexural strength measurements up to 1,400 C have confirmed the improved high-temperature strength and creep resistance over conventional LAS. The fracture toughness is also higher than that of LAS. The results suggest that the new composition may be chosen as a better candidate matrix for SiC-fiber-reinforced composites.

  17. Sodium Test

    MedlinePlus

    ... be limited. Home Visit Global Sites Search Help? Sodium Share this page: Was this page helpful? Also known as: Na Formal name: Sodium Related tests: Chloride , Bicarbonate , Potassium , Electrolytes , Osmolality , Basic ...

  18. Synthetic oils

    NASA Technical Reports Server (NTRS)

    Hatton, R. E.

    1973-01-01

    Synthetic lubricants are discussed by chemical class and their general strengths and weaknesses in terms of lubrication properties are analyzed. Comparative ratings are given for 14 chemical classes and are used as a guide for lubricant selection. The effects of chemical structure on the properties of the lubricant are described with special emphasis on thermal stability. The diversity of synthetic lubricants which is provided by the wide range of properties permits many applications, some of which are reported.

  19. Synthetic environments

    NASA Astrophysics Data System (ADS)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  20. Synthetic Jets

    NASA Technical Reports Server (NTRS)

    Milanovic, Ivana M.

    2003-01-01

    Current investigation of synthetic jets and synthetic jets in cross-flow examined the effects of orifice geometry and dimensions, momentum-flux ratio, cluster of orifices, pitch and yaw angles as well as streamwise development of the flow field. This comprehensive study provided much needed experimental information related to the various control strategies. The results of the current investigation on isolated and clustered synthetic jets with and without cross-flow will be further analyzed and documented in detail. Presentations at national conferences and publication of peer- reviewed journal articles are also expected. Projected publications will present both the mean and turbulent properties of the flow field, comparisons made with the data available in an open literature, as well as recommendations for the future work.

  1. Evidence for lithium-aluminosilicate supersaturation of pegmatite-forming melts

    NASA Astrophysics Data System (ADS)

    Maneta, Victoria; Baker, Don R.; Minarik, William

    2015-07-01

    New experimental data on the solubility of lithium (Li) at spodumene (LiAlSi2O6) and petalite (LiAlSi4O10) saturation at 500 MPa and 550-750 °C reveal evidence for lithium supersaturation of pegmatite-forming melts before the formation of Li-aluminosilicates. The degree of Li enrichment in granitic melts can reach ~11,000 ppm above the saturation value before the crystallization of Li-aluminosilicate minerals at lower temperatures. Comparison of the experimental results with the spodumene-rich Moblan pegmatite (Quebec) is consistent with extreme Li enrichment of the pegmatite-forming melt prior to emplacement, which cannot be explained with equilibrium crystallization of Li-aluminosilicates from a common granitic melt. The results of this study support the model of disequilibrium fractional crystallization through liquidus undercooling as the most plausible mechanism for the generation of such Li-rich ore resources.

  2. Highly acidic mesostructured aluminosilicates assembled from surfactant-mediated zeolite hydrolysis products.

    PubMed

    Wang, Hui; Liu, Yu; Pinnavaia, Thomas J

    2006-03-16

    The surfactant-mediated hydrolysis of ZSM-5 zeolite affords five-membered ring subunits that can be readily incorporated into the framework walls of a hexagonal mesostructured aluminosilicate, denoted MSU-Z. The five-membered ring subunits, which are identifiable by infrared spectroscopy, impart unprecedented acidity to the mesostructure, as judged by cumene cracking activity at 300 degrees C. Most notably, MSU-Z aluminosilicate made through the base hydrolysis of ZSM-5 in the presence of cetyltrimethylammonium ions exhibits a cumene conversion of 73%, which is 6.7-fold higher than the conversion provided by a conventional MCM-41. This approach to stabilizing zeolitic subunits through surfactant-mediated hydrolysis of zeolites appears to be general. The hydrolysis of USY zeolite under analogous hydrolytic conditions also affords zeolitic fragments that boost the acidity of the mesostructure in comparison to equivalent compositions prepared from conventional aluminosilicate precursors.

  3. Synthesis and immobilization of silver nanoparticles on aluminosilicate nanotubes and their antibacterial properties

    NASA Astrophysics Data System (ADS)

    Ipek Yucelen, G.; Connell, Rachel E.; Terbush, Jessica R.; Westenberg, David J.; Dogan, Fatih

    2016-04-01

    A novel colloidal method is presented to synthesize silver nanoparticles on aluminosilicate nanotubes. The technique involves decomposition of AgNO3 solution to Ag nanoparticles in the presence of aluminosilicate nanotubes at room temperature without utilizing of reducing agents or any organic additives. Aluminosilicate nanotubes are shown to be capable of providing a unique chemical environment, not only for in situ conversion of Ag+ into Ag0, but also for stabilization and immobilization of Ag nanoparticles. The synthesis strategy described here could be implemented to obtain self-assembled nanoparticles on other single-walled metal oxide nanotubes for unique applications. Finally, we demonstrated that nanotube/nanoparticle hybrid show strong antibacterial activity toward Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli.

  4. Quantum-chemical investigation of mechanism of dehydroxylation of crystalline and amorphous aluminosilicates

    SciTech Connect

    Senchenya, I.N.; Chuvylkin, N.D.; Kazanskii, V.B.

    1986-07-01

    Within the framework of the cluster approach and the semiempirical SCF MO LCAO method in the CNDO/BW valence approximation, possible pathways have been compared for the dehydroxylation of aluminosilicate systems. It has been shown that dehydroxylation as a result of splitting of a water molecule from an acidic bridge hydroxyl group and a more basic terminal group Al-OH is the most energyfavorable. Apparently, such a dehydroxylation pathway is primarily characteristic for amorphous aluminosilicates. Typical of crystalline aluminosilicates at moderate heat-treating temperature is dehydroxylation through splitting of a water molecule from an acidic bridge hydroxyl group and a neutral Si-OH group; at higher temperatures, there is a possible pathway of dehydroxylation of highsilica zeolites as a result of condensation of two acidic surface hydroxyls.

  5. Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX)

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.; Wu, James K.

    2010-10-01

    We report results on lithium alumino-silicate ion source development in preparation for warmdense-matter heating experiments on the new Neutralized Drift Compression Experiment (NDCXII). The practical limit to the current density for a lithium alumino-silicate source is determined by the maximum operating temperature that the ion source can withstand before running into problems of heat transfer, melting of the alumino-silicate material, and emission lifetime. Using small prototype emitters, at a temperature of ~;;1275 oC, a space-charge-limited Li+ beam current density of J ~;;1 mA/cm2 was obtained. The lifetime of the ion source was ~;;50 hours while pulsing at a rate of 0.033 Hz with a pulse duration of 5-6 mu s.

  6. Distribution of aflatoxins in tissues of growing pigs fed an aflatoxin-contaminated diet amended with a high affinity aluminosilicate sorbent.

    PubMed

    Beaver, R W; Wilson, D M; James, M A; Haydon, K D; Colvin, B M; Sangster, L T; Pikul, A H; Groopman, J D

    1990-02-01

    The effect of hydrated sodium calcium aluminosilicate (HSCAS) added to the diet of swine fed an aflatoxin-contaminated diet on tissue aflatoxin levels was investigated. Pigs were fed control (less than 10 ng/g B1 + B2), contaminated (500-600 ng/g B1 + B2), and contaminated +0.5% HSCAS diets. Tissues analyzed for the presence of aflatoxin B1, B2, and M1 residues included liver, muscle, kidney, and adipose. Addition of HSCAS to the contaminated diet significantly reduced the amount of M1 in liver, kidney, and muscle tissue. Aflatoxin B1 was not reduced in liver or kidney, but was decreased in muscle.

  7. Aflatoxin adsorbent capacity of two Mexican aluminosilicates in experimentally contaminated chick diets.

    PubMed

    Márquez Márquez, R N; Tejada de Hernandez, I

    1995-01-01

    To study the aflatoxin-adsorbent capacity of two Mexican aluminosilicates (ALS) identified as Atapulgita (AT) and Füller earth (FE), these ALS were compared with a commercial aluminosilicate, Novasil (NV), at two concentrations (0.05 and 1.0%) added to chick diets with 55% of experimentally contaminated corn (200 micrograms/kg). Eight treatments were studied with two replicates for treatment and four chicks per cage. Results (weight gain, feed efficiency, gross and microscopic pathology) at 3 weeks showed that both Mexican ALS were as efficient as the commercial material in protecting chicks against the aflatoxin toxicity. PMID:7664939

  8. Spectroscopy and laser action of rhodamine 6G doped aluminosilicate xerogels

    SciTech Connect

    McKiernan, J.M.; Yamanaka, S.A.; Dunn, B.; Zink, J.I. )

    1990-07-26

    Rhodamine 6G (R6G) doped aluminosilicate glass synthesized by the sol-gel method exhibits laser action. Transparent 5 mm {times} 5 mm {times} 10 mm monoliths were used as cast in a simple laser cavity. This new material was pumped at rates of up to 25 Hz and was still active after as many as 40,000 pump pulses. Luminescence and free-running laser spectra are measured. The dependence of the R6G doped aluminosilicate dye laser output on the number of pump pulses and the pump pulse energy is discussed.

  9. Aflatoxin adsorbent capacity of two Mexican aluminosilicates in experimentally contaminated chick diets.

    PubMed

    Márquez Márquez, R N; Tejada de Hernandez, I

    1995-01-01

    To study the aflatoxin-adsorbent capacity of two Mexican aluminosilicates (ALS) identified as Atapulgita (AT) and Füller earth (FE), these ALS were compared with a commercial aluminosilicate, Novasil (NV), at two concentrations (0.05 and 1.0%) added to chick diets with 55% of experimentally contaminated corn (200 micrograms/kg). Eight treatments were studied with two replicates for treatment and four chicks per cage. Results (weight gain, feed efficiency, gross and microscopic pathology) at 3 weeks showed that both Mexican ALS were as efficient as the commercial material in protecting chicks against the aflatoxin toxicity.

  10. Calculation of the Aluminosilicate Half-Life Formation Time in the 2H Evaporator

    SciTech Connect

    Fondeur, F.F.

    2000-09-21

    The 2H Evaporator contains large quantities of aluminosilicate solids deposited on internal fixtures. The proposed cleaning operations will dissolve the solids in nitric acid. Operations will then neutralize the waste prior to transfer to a waste tank. Combining recent calculations of heat transfer for the 2H Evaporator cleaning operations and laboratory experiments for dissolution of solid samples from the pot, the authors estimated the re-formation rate for aluminosilicates during cooling. The results indicate a half-life formation of 17 hours when evaporator solution cools from 60 degrees C and 9 hours when cooled from 90 degrees C.

  11. The Yb-doped aluminosilicate fibers photodarkening mechanism based on the charge-transfer state excitation

    NASA Astrophysics Data System (ADS)

    Rybaltovsky, A. A.; Bobkov, K. K.; Velmiskin, V. V.; Umnikov, A. A.; Shestakova, I. A.; Guryanov, A. N.; Likhachev, M. E.; Bubnov, M. M.; Dianov, E. M.

    2014-03-01

    We have studied the photodarkening effect in fiber preforms with an ytterbium-doped aluminosilicate glass core. The room-temperature stable Yb2+ ions formation in the glass matrix under both UV- and NIR-pumping irradiation was revealed by the method of absorption spectra analysis and the fluorescence spectroscopy technique. Comparative studies of preforms and crystals samples luminescence spectra, obtained under UV-excitation, were performed. A general mechanism of Yb2+ ions and aluminium oxygen-hole centers (Al-OHC) formation as a result of photoinduced process of Yb3+ ions excitation to "charge-transfer state" (CTS) was found for both Yb:YAG crystal and aluminosilicate glass.

  12. Synthetic Astrobiology

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2015-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  13. Synthetic Astrobiology

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2016-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. And what about the limits for life? Can we create organisms that expand the envelope for life? In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  14. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3.

    PubMed

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-01-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3. PMID:25791958

  15. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3

    PubMed Central

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-01-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3. PMID:25791958

  16. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3.

    PubMed

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-03-20

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3.

  17. One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3

    NASA Astrophysics Data System (ADS)

    Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

    2015-03-01

    Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3.

  18. In-situ growth of porous alumino-silicates and fabrication of nano-porous membranes

    NASA Astrophysics Data System (ADS)

    Kodumuri, Pradeep

    2009-12-01

    Feasibility of depositing continuous films of nano-porous alumino-silicates, primarily zeolites and MCM-41, on metallic and non-metallic substrates was examined with an aim to develop membranes for separation of gaseous mixtures and also for application as hydrogen storage material. Mesoporous silica was deposited in-side the pores of these nano-porous disks with an aim to develop membranes for selective separations. Our study involves supported zeolite film growth on substrates using in-situ hydrothermal synthesis. Faujasite, Silicalite and Mesoporous silica have been grown on various metallic and non-metallic supports. Metallic substrates used for film growth included anodized titanium, sodium hydroxide treated Titanium, Anodized aluminum, and sintered copper. A non-metallic substrate used was nano-porous aluminum oxide. Zeolite film growth was characterized using Scanning Electron Microscope (AMRAY 1820) and High Resolution Transmission electron microscope. Silicalite was found to grow uniformly on all the substrates to form a uniform and closely packed film. Faujasite tends to grow in the form of individual particles which do not inter-grow like silicalite to form a continuous film. Mesoporous silica was found to grow uniformly on anodized aluminum compared to growth on sintered copper and anodized titanium. Mesoporous silica growth on AnodiscRTM was found to cover more than half the surface of the substrate. Commercially obtained AnodiscRTM was found to have cylindrical channels of the pore branching into each other and since we needed pore channels of uniform dimension for Mesoporous silica growth, we have fabricated nano-porous alumina with uniform pore channels. Nano-porous alumina membranes containing uniform distribution of through thickness cylindrical pore channels were fabricated using anodization of aluminum disks. Free-standing nano-porous alumina membranes were used as templates for electro-deposition in order to fabricate nickel and palladium nano

  19. Technetium (VII) Co-precipitation with Framework Aluminosilicates

    SciTech Connect

    Harsh, James B.; Dickson, Johnbull Otah; Pierce, Eric M.; Bargar, John

    2015-07-13

    Technetium-99 (99Tc), a long-lived radionuclide, is one of the most widespread contaminants within the Hanford subsurface. At some depths, it is only extractable with strong acids, suggesting incorporation into a solid phase. We hypothesized that Tc may have coprecipitated with feldspathoid aluminosilicates under waste tanks that had leaked caustic solutions into the vadose zone. Our objectives were to determine if Tc could be incorporated into the feldspathoids cancrinite and sodalite and under what conditions coprecipitation could occur. Our hypothesis was that sodalite was more likely to incorporate and retain Tc. Our approach was to use known methods of feldspathoid formation in solutions resembling those in Hanford waste tanks contacting sediments in terms of major ion (Na, NO3, OH, Al(OH)4, and Si(OH)4 concentrations. In some cases, Al and Si were supplied from zeolite. We used perrhenate (ReO4) as a surrogate for pertechnetate (TcO4) to avoid the radioactivity. The major findings of this study were 1) ReO4 could be incorporated into either sodalite or cancrinite but the concentration in the solid was < 1% of the competing ion Cl, NO3, or NO2. 2) The small amount of ReO4 incorporated was not exchangeable with NO3 or NO2. 3) In sodalite, NO3 was highly preferred over ReO4 but significant Re-sodalite was formed when the mole fraction in solution (Re/Re+N) exceeded 0.8. 4) A nonlinear relation between the unit cell parameter and amount of Re incorporated suggested that a separate Re-sodalite phase was formed rather than a solid solution. 5) We determined that sodalite preference for sodalite in the presence of different anions increased with the ionic size of the competing anion: Cl < CO3 < NO3 < SO4 < MnO4 < WO4 and significant incorporation did not occur unless the difference in anion radii was less than 12%. 6) Re(VII) was not significantly reduced to Re(IV) under the conditions of this experiment and Re appeared to be a good surrogate for Tc under oxidizing

  20. Aluminosilicate melts and glasses at 1 to 3 GPa: Temperature and pressure effects on recovered structural and density changes

    USGS Publications Warehouse

    Bista, S; Stebbins, Jonathan; Hankins, William B.; Sisson, Thomas W.

    2015-01-01

    In the pressure range in the Earth’s mantle where many basaltic magmas are generated (1 to 3 GPa) (Stolper et al. 1981), increases in the coordination numbers of the network-forming cations in aluminosilicate melts have generally been considered to be minor, although effects on silicon and particularly on aluminum coordination in non-bridging oxygen-rich glasses from the higher, 5 to 12 GPa range, are now well known. Most high-precision measurements of network cation coordination in such samples have been made by spectroscopy (notably 27Al and 29Si NMR) on glasses quenched from high-temperature, high-pressure melts synthesized in solid-media apparatuses and decompressed to room temperature and 1 bar pressure. There are several effects that could lead to the underestimation of the extent of actual structural (and density) changes in high-pressure/temperature melts from such data. For non-bridging oxygen-rich sodium and calcium aluminosilicate compositions in the 1 to 3 GPa range, we show here that glasses annealed near to their glass transition temperatures systematically record higher recovered increases in aluminum coordination and in density than samples quenched from high-temperature melts. In the piston-cylinder apparatus used, rates of cooling through the glass transition are measured as very similar for both higher and lower initial temperatures, indicating that fictive temperature effects are not the likely explanation of these differences. Instead, transient decreases in melt pressure during thermal quenching, which may be especially large for high initial run temperatures, of as much as 0.5 to 1 GPa, may be responsible. As a result, the equilibrium proportion of high-coordinated Al in this pressure range may be 50 to 90% greater than previously estimated, reaching mean coordination numbers (e.g., 4.5) that are probably high enough to significantly affect melt properties. New data on jadeite (NaAlSi2O6) glass confirm that aluminum coordination increase

  1. Interface Induced Growth and Transformation of Polymer-Conjugated Proto-Crystalline Phases in Aluminosilicate Hybrids: A Multiple-Quantum (23)Na-(23)Na MAS NMR Correlation Spectroscopy Study.

    PubMed

    Brus, Jiri; Kobera, Libor; Urbanova, Martina; Doušová, Barbora; Lhotka, Miloslav; Koloušek, David; Kotek, Jiří; Čuba, Pavel; Czernek, Jiri; Dědeček, Jiří

    2016-03-22

    Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix. This secondary epoxide phase not only enhances the mechanical integrity of the resulting hybrids but also introduces additional binding sites accessible for compensating negative charge on the aluminosilicate framework. This way, the polymer network initiates growth and subsequent transformation of protocrystalline short-range ordered zeolite domains that are located at the organic-inorganic interface. By applying an experimental approach based on 2D (23)Na-(23)Na double-quantum (DQ) MAS NMR spectroscopy, we discovered multiple sodium binding sites in these protocrystalline domains, in which immobilized Na(+) ions form pairs or small clusters. It is further demonstrated that these sites, the local geometry of which allows for the pairing of sodium ions, are preferentially occupied by Pb(2+) ions during the ion exchange. The proposed synthesis protocol thus allows for the preparation of a novel type of geopolymer hybrids with polymer-conjugated zeolite phases suitable for capturing and storage of metal cations. The demonstrated (23)Na-(23)Na DQ MAS NMR combined with DFT calculations represents a suitable approach for understanding the role of Na(+) ions in aluminositicate solids and related inorganic-organic hybrids, particularly their specific arrangement and clustering at interfacial areas.

  2. A highly crystalline microporous hybrid organic-inorganic aluminosilicate resembling the AFI-type zeolite.

    PubMed

    Bellussi, Giuseppe; Millini, Roberto; Montanari, Erica; Carati, Angela; Rizzo, Caterina; Parker, Wallace O; Cruciani, Giuseppe; de Angelis, Alberto; Bonoldi, Lucia; Zanardi, Stefano

    2012-07-28

    ECS-14, a crystalline microporous hybrid organic-inorganic aluminosilicate, has been synthesized by using 1,4-bis-(triethoxysilyl)-benzene (BTEB) as a source of silica. Its structure contains a system of linear channels with 12-membered ring openings, running along the [001] direction, resembling the pore architecture of the AFI framework type. PMID:22717682

  3. EFFECT OF IMPURITIES ASSOCIATED WITH ALUMINOSILICATES ON ARSENIC SORPTION AND OXIDATION

    EPA Science Inventory

    Arsenite, As(III), and arsenate, As(V), are of increasing environmental concern. Risk assessment and risk management of arsenic contaminated sites requires a better understanding of arsenic-mineral interactions. Aluminosilicate minerals, such as feldspars and clays, are the mos...

  4. Epoxide ring-opening and Meinwald rearrangement reactions of epoxides catalyzed by mesoporous aluminosilicates.

    PubMed

    Robinson, Mathew W C; Davies, A Matthew; Buckle, Richard; Mabbett, Ian; Taylor, Stuart H; Graham, Andrew E

    2009-06-21

    Mesoporous aluminosilicates efficiently catalyze the ring-opening of epoxides to produce beta-alkoxyalcohols in high yields under extremely mild reaction conditions. These materials also catalyze the corresponding Meinwald rearrangement in non-nucleophilic solvents to give aldehydes which can be trapped in situ to provide the corresponding acetals in an efficient tandem process.

  5. High-aluminum-affinity silica is a nanoparticle that seeds secondary aluminosilicate formation.

    PubMed

    Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J

    2013-01-01

    Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m(2) g(-1) and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates.

  6. Formic acid, ethanol in vycor glass, and water in aluminosilicate zeolites

    SciTech Connect

    Loong, C.K.; Trouw, F.; Iton, L.E.

    1993-11-01

    We present results of incoherent inelastic neutron-scattering experiments on formic acid, ethanol in vycor glass, and water in aluminosilicate zeolites performed at Argonne`s spallation neutron source, IPNS. The forming and breaking of hydrogen bonds are discussed in terms of translational and rotational diffusion, and vibrational footprints of various molecular species in these systems.

  7. Sorption of cesium and strontium from mineralized aqueous solutions on natural aluminosilicates modified by ferrocyanides of heavy metals

    SciTech Connect

    Panasyugin, A.S.; Trofimenko, N.E.; Masherova, N.P.; Rat`ko, A.I.; Golikova, N.I.

    1994-03-10

    The sorption behavior of natural aluminosilicates (bentonite and clinoptilolite) and aluminosilicates modified by ferrocyanides of heavy metals has been studied relative to radionuclides {sup 137}Cs and {sup 90}Sr in the presence of various quantities of alkali and alkaline-earth ions (e.g. surface waters). It has been shown that the distribution coefficients of the modified samples may exceed 100 for Sr{sup 2+} and 10,000 for Cs{sup +}; however, with a concentration of mineral background over 1.0 g{center_dot}liter, the competing ions strongly depress the sorption properties of the aluminosilicates.

  8. Sodium Oxybate

    MedlinePlus

    ... used to prevent attacks of cataplexy (episodes of muscle weakness that begin suddenly and last for a ... of your body that you cannot control, sweating, muscle cramps, and fast heartbeat.Sodium oxybate may help ...

  9. Synthetic Cathinones ("Bath Salts")

    MedlinePlus

    ... still unknown about how synthetic cathinones affect the human brain. Researchers do know that synthetic cathinones are chemically ... of the chemicals in synthetic cathinones affect the human brain. Synthetic cathinones can cause: nosebleeds paranoia increased sociability ...

  10. Synthetic Cannabinoids.

    PubMed

    Mills, Brooke; Yepes, Andres; Nugent, Kenneth

    2015-07-01

    Synthetic cannabinoids (SCBs), also known under the brand names of "Spice," "K2," "herbal incense," "Cloud 9," "Mojo" and many others, are becoming a large public health concern due not only to their increasing use but also to their unpredictable toxicity and abuse potential. There are many types of SCBs, each having a unique binding affinity for cannabinoid receptors. Although both Δ-tetrahydrocannabinol (THC) and SCBs stimulate the same receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), studies have shown that SCBs are associated with higher rates of toxicity and hospital admissions than is natural cannabis. This is likely due to SCBs being direct agonists of the cannabinoid receptors, whereas THC is a partial agonist. Furthermore, the different chemical structures of SCBs found in Spice or K2 may interact in unpredictable ways to elicit previously unknown, and the commercial products may have unknown contaminants. The largest group of users is men in their 20s who participate in polydrug use. The most common reported toxicities with SCB use based on studies using Texas Poison Control records are tachycardia, agitation and irritability, drowsiness, hallucinations, delusions, hypertension, nausea, confusion, dizziness, vertigo and chest pain. Acute kidney injury has also been strongly associated with SCB use. Treatment mostly involves symptom management and supportive care. More research is needed to identify which contaminants are typically found in synthetic marijuana and to understand the interactions between different SBCs to better predict adverse health outcomes.

  11. Synthetic Brainbows

    PubMed Central

    Wan, Y.; Otsuna, H.; Hansen, C.

    2014-01-01

    Brainbow is a genetic engineering technique that randomly colorizes cells. Biological samples processed with this technique and imaged with confocal microscopy have distinctive colors for individual cells. Complex cellular structures can then be easily visualized. However, the complexity of the Brainbow technique limits its applications. In practice, most confocal microscopy scans use different florescence staining with typically at most three distinct cellular structures. These structures are often packed and obscure each other in rendered images making analysis difficult. In this paper, we leverage a process known as GPU framebuffer feedback loops to synthesize Brainbow-like images. In addition, we incorporate ID shuffing and Monte-Carlo sampling into our technique, so that it can be applied to single-channel confocal microscopy data. The synthesized Brainbow images are presented to domain experts with positive feedback. A user survey demonstrates that our synthetic Brainbow technique improves visualizations of volume data with complex structures for biologists. PMID:25018576

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  13. A Calorimetric Study of Almandine: Are the Thermodynamic Properties of the End-Member Aluminosilicate Garnets Finally Known Quantitatively?

    NASA Astrophysics Data System (ADS)

    Dachs, E.; Geiger, C. A.; Benisek, A.

    2012-12-01

    The aluminosilicate garnets (E3Al2Si3O12 with E = Fe2+, Mn2+, Ca, Mg) form an important rock-forming mineral group. Much study has been directed toward determining their thermodynamic properties. The iron end-member almandine (Fe3Al2Si3O12) is a key phase in many petrologic investigations. As part of an ongoing calorimetric and thermodynamic study of the aluminosilicate garnets, the heat capacity of three synthetic well-characterized polycrystalline almandine garnets and one natural almandine-rich single crystal was measured. The various garnets were characterized by optical microscopy, electron-microprobe analysis, X-ray powder diffraction and 57Fe Mössbauer spectroscopy. Heat capacity measurements were performed in the temperature range 3 to 300 K using relaxation calorimetry and between 282 and 764 K using DSC methods. From the former, So values between 336.7 ± 0.8 and 337.8 ± 0.8 J/molK are calculated for the different samples. The smaller value is considered the best So for end-member stoichiometric almandine, because it derives from the "best" Fe3+-free synthetic sample. The Cp behavior for almandine at T > 298 K is given by the polynomial (in J/molK): Cp = 649.06(±4) - 3837.57(±122)T-0.5 - 1.44682(±0.06)107T-2 + 1.94834(±0.09)109T-3, which is calculated using DSC data together with one published heat-content datum determined by transposed-drop calorimetry along with a new determination that gives H1181K - H302K = 415.0 ± 3.2 kJ/mole. Almandine shows a λ-type heat-capacity anomaly at low temperatures resulting from a paramagnetic-antiferromagnetic phase transition at about 9 K. The lattice heat capacity was calculated using the single-parameter phonon dispersion model of Komada and Westrum (1997), which allows the non-lattice heat capacity (Cex) behavior to be modelled. An analysis shows the presence of an electronic heat-capacity contribution (Cel - Schottky anomaly) around 17 K that is superimposed on a larger magnetic heat-capacity effect (Cmag

  14. Optical absorption of Co 2+ in gel-derived aluminosilicate glass-ceramics

    NASA Astrophysics Data System (ADS)

    Duan, Xiulan; Yuan, Duorong; Cheng, Xiufeng; Wang, Xinqiang

    2006-07-01

    Pure and Co 2+-doped aluminosilicate gels were prepared by the sol-gel method from two different aluminum salts, aluminum-iso-propoxide and aluminum nitrate, and heat-treated at 40-1200 °C. Visible and near-infrared (NIR) absorption spectra of the heated samples were studied. When the heat-treatment temperature was 1100 °C, Co 2+-doped aluminosilicate samples, obtained by using aluminum-iso-propoxide, crystallized to Al 2O 3 nanocrystals and exhibited a broad absorption band in the range of 1200-1600 nm, which is characteristic of tetrahedral Co 2+ ions in crystals. The existence of the broad absorption band has allowed us to consider this kind of material as possible candidate for passive Q-switched materials in the NIR region. While the sample prepared from aluminum nitrate was amorphous when heated to 1200 °C.

  15. Alzheimer's disease may begin in the nose and may be caused by aluminosilicates.

    PubMed

    Roberts, E

    1986-01-01

    Genetic factors may interact with aging changes in the nasal mucociliary apparatus to increase the probability that ubiquitously occurring aluminosilicates may enter sensory neurons of the olfactory epithelium and spread transneuronally to several olfactory-related areas of the brain, thereby initiating changes that eventually result in neuronal damage typical of Alzheimer's disease. A speculative sequence of events is suggested by which neuronally-contained aluminosilicates might cleave or otherwise alter a normal cellular protein in such a manner that aggregates would arise that could interfere with cellular function and which also could act in a pseudo-infective manner, relaxing translational and transcriptional controls in the synthesis of the native protein. Some relevant experiments and potential therapies arising from the hypothesis presented are discussed.

  16. Maximizing the catalytic function of hydrogen spillover in platinum-encapsulated aluminosilicates with controlled nanostructures.

    PubMed

    Im, Juhwan; Shin, Hyeyoung; Jang, Haeyoun; Kim, Hyungjun; Choi, Minkee

    2014-02-25

    Hydrogen spillover has been studied for several decades, but its nature, catalytic functions and even its existence remain topics of vigorous debate. This is a consequence of the lack of model catalysts that can provide direct evidences of the existence of hydrogen spillover and simplify the catalytic interpretation. Here we use platinum encapsulated in a dense aluminosilicate matrix with controlled diffusional properties and surface hydroxyl concentrations to elucidate the catalytic functions of hydrogen spillover. The catalytic investigation and theoretical modelling show that surface hydroxyls, presumably Brønsted acids, are crucial for utilizing the catalytic functions of hydrogen spillover on the aluminosilicate surface. The catalysts with optimized nanostructure show remarkable activities in hydro-/dehydrogenation, but virtually no activity for hydrogenolysis. This distinct chemoselectivity may be beneficial in industrially important hydroconversions such as propane dehydrogenation to propylene because the undesired hydrogenolysis pathway producing light hydrocarbons of low value (methane and ethane) is greatly suppressed.

  17. Oxidative damage in Alzheimer's dementia, and the potential etiopathogenic role of aluminosilicates, microglia and micronutrient interactions.

    PubMed

    Evans, P H; Yano, E; Klinowski, J; Peterhans, E

    1992-01-01

    While evidence implicating free radical oxidative processes in the etiopathogenesis of Alzheimer's dementia is accumulating, the specific cellular and biochemical mechanisms involved remain to be identified. The potential pathogenic role of microglial cells in neurodegenerative processes is indicated by the finding that purified murine microglial cells exposed in vitro to various model aluminosilicate particles stimulate the generation of tissue-injurious free radical reactive oxygen metabolites. Analogous inorganic aluminosilicate deposits have been reported to occur in the core of the characteristic senile plaques found in the brains of Alzheimer disease subjects. The possible modulation of free radical oxidative activity by antioxidant micronutrients and pharmacological agents, provides a rational basis for further preventative and therapeutic clinical investigations.

  18. Amphiphilic Organic-Inorganic Hybrid Zeotype Aluminosilicate like a Nanoporous Crystallized Langmuir-Blodgett Film.

    PubMed

    Ikeda, Takuji; Hiyoshi, Norihito; Matsuura, Shun-ichi; Kodaira, Tetsuya; Nakaoka, Takuma; Irisa, Ami; Kawano, Miki; Yamamoto, Katsutoshi

    2015-06-26

    A new organic-inorganic hybrid zeotype compound with amphiphilic one-dimensional nanopore and aluminosilicate composition was developed. The framework structure is composed of double aluminosilicate layers and 12-ring nanopores; a hydrophilic layer pillared by Q(2) silicon atom species and a lipophilic layer pillared by phenylene groups are alternately stacked, and 12-ring nanopores perpendicularly penetrate the layers. The framework topology looks similar to that of an AFI-type zeolite but possesses a quasi-multidimensional pore structure consisting of a 12-ring channel and intersecting small pores equivalent to 8-rings. The hybrid material with alternately laminated lipophilic and hydrophilic nanospaces can be assumed as a crystallized Langmuir-Blodgett film. It demonstrates microporous adsorption for both hydrophilic and lipophilic adsorptives, and its outer surface tightly adsorbs lysozyme whose molecular size is much larger than its micropore opening. Our results suggest the possibility of designing porous adsorbent with high amphipathicity.

  19. High-Aluminum-Affinity Silica Is a Nanoparticle That Seeds Secondary Aluminosilicate Formation

    PubMed Central

    Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J.

    2013-01-01

    Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m2 g-1 and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates. PMID:24349573

  20. One-step synthesis of hydrothermally stable mesoporous aluminosilicates with strong acidity

    SciTech Connect

    Yang Dongjiang; Xu Yao Wu Dong; Sun Yuhan

    2008-09-15

    Using tetraethylorthosilicate (TEOS), polymethylhydrosiloxane (PMHS) and aluminium isopropoxide (AIP) as the reactants, through a one-step nonsurfactant route based on PMHS-TEOS-AIP co-polycondensation, hydrothermally stable mesoporous aluminosilicates with different Si/Al molar ratios were successfully prepared. All samples exclusively showed narrow pore size distribution centered at 3.6 nm. To assess the hydrothermal stability, samples were subjected to 100 deg. C distilled water for 300 h. The boiled mesoporous aluminosilicates have nearly the same N{sub 2} adsorption-desorption isotherms and the same pore size distributions as those newly synthesized ones, indicating excellent hydrothermal stability. The {sup 29}Si MAS NMR spectra confirmed that PMHS and TEOS have jointly condensed and CH{sub 3} groups have been introduced into the materials. The {sup 27}Al MAS NMR spectra indicated that Al atoms have been incorporated in the mesopore frameworks. The NH{sub 3} temperature-programmed desorption showed strong acidity. Due to the existence of large amount of CH{sub 3} groups, the mesoporous aluminosilicates obtained good hydrophobicity. Owing to the relatively large pore and the strong acidity provided by the uniform four-coordinated Al atoms, the excellent catalytic performance for 1,3,5-triisopropylbenzene cracking was acquired easily. The materials may be a profitable complement for the synthesis of solid acid catalysts. - Graphical abstract: Based on the nonsurfactant method, a facile one-step synthesis route has been developed to prepare methyl-modified mesoporous aluminosilicates that possessed hydrothermal stability and strong acidity.

  1. Adsorption into mineral mesopores as a stabilization mechanism for organic matter on aluminosilicates

    SciTech Connect

    Mayer, L.M. . Dept. of Oceanography)

    1992-01-01

    Measurements of mineral specific surface area and total organic carbon (TOC) indicate that many marine shelf and estuarine sediments, and aluminosilicate soils, have a TOC content equivalent to a monolayer of organic matter covering all mineral surfaces. Density separations of discrete organic particulates from mineral-associated OC are consistent with a primarily adsorbed nature foremost of TOC. Nitrogen gas adsorption data also suggest extensive organic coatings on the mineral grains. Downcore analyses indicate that sediments with TOC starting in excess of monolayer-equivalent (ME) levels decay with core depth to the ME level and then markedly slow their OC loss rate--i.e., the ME level determines the refractory background concentration of TOC. Pore size distributions of marine sediments, determined by nitrogen adsorption or mercury porosimetry, indicate that most surface area of minerals is to be found in pores of < 10 nm diameter. These observations lead to the hypothesis that organic matter is stabilized on aluminosilicate minerals by adsorption into pores too small to allow entry or functioning of the hydrolytic enzymes responsible for OC degradation. This hypothesis is consistent with, but does not require, humification reactions as necessary for OC stabilization. The ME levels of TOC found in continental platform aluminosilicates hence represent a cap on the amount of organic matter that can be protected in this manner and thus attain a residence time of > 1,000 y. Stabilization of higher levels of TOC, as in acid soils or anoxic sediments, presumably results from protection by different mechanisms.

  2. Mesoporous aluminosilicates with ordered hexagonal structure, strong acidity, and extraordinary hydrothermal stability at high temperatures.

    PubMed

    Zhang, Z; Han, Y; Xiao, F S; Qiu, S; Zhu, L; Wang, R; Yu, Y; Zhang, Z; Zou, B; Wang, Y; Sun, H; Zhao, D; Wei, Y

    2001-05-30

    Highly ordered hexagonal mesoporous aluminosilicates (MAS-5) with uniform pore sizes have been successfully synthesized from assembly of preformed aluminosilcate precursors with cetyltrimethylammonium bromide (CTAB) surfactant. The aluminosilicate precursors were obtained by heating, at 100--140 degrees C for 2--10 h, aluminasilica gels at the Al(2)O(3)/SiO(2)/TEAOH/H(2)O molar ratios of 1.0/7.0--350/10.0--33.0/500--2000. Mesoporous MAS-5 shows extraordinary stability both in boiling water (over 300 h) and in steam (800 degrees C for 2 h). Temperature-programmed desorption of ammonia shows that the acidic strength of MAS-5 is much higher than that of MCM-41 and is comparable to that of microporous Beta zeolite. In catalytic cracking of 1,3,5-triisopropylbenzene and alkylation of isobutane with butene, MAS-5 exhibits greater catalytic activity and selectivity, as compared with MCM-41 and HZSM-5. The MAS-5 samples were characterized with infrared, UV--Raman, and NMR spectroscopy and numerous other techniques. The results suggest that MAS-5 consists of both mesopores and micropores and that the pore walls of MAS-5 contain primary and secondary structural building units, similar to those of microporous zeolites. Such unique structural features might be responsible for the observed strong acidity and high thermal stability of the mesoporous aluminosilicates with well-ordered hexagonal symmetry.

  3. Secondary Ion Mass Spectrometry of Zeolite Materials: Observation of Abundant Aluminosilicate Oligomers Using an Ion Trap

    SciTech Connect

    Groenewold, Gary Steven; Kessinger, Glen Frank; Scott, Jill Rennee; Gianotto, Anita Kay; Appelhans, Anthony David; Delmore, James Edward

    2000-12-01

    Oligomeric oxyanions were observed in the secondary ion mass spectra (SIMS) of zeolite materials. The oxyanions have the general composition AlmSinO2(m+n)H(m-1)- (m + n = 2 to 8) and are termed dehydrates. For a given mass, multiple elemental compositions are possible because (Al + H) is an isovalent and isobaric substitute for Si. Using 18 keV Ga+ as a projectile, oligomer abundances are low relative to the monomers. Oligomer abundance can be increased by using the polyatomic projectile ReO4- (~5 keV). Oligomer abundance can be further increased using an ion trap (IT-) SIMS; in this instrument, long ion lifetimes (tens of ms) and relatively high He pressure result in significant collisional stabilization and increased high-mass abundance. The dehydrates rapidly react with adventitious H2O present in the IT-SIMS to form mono-, di-, and trihydrates. The rapidity of the reaction and comparison to aluminum oxyanion hydration suggest that H2O adds to the aluminosilicate oxyanions in a dissociative fashion, forming covalently bound product ions. In addition to these findings, it was noted that production of abundant oligomeric aluminosilicates could be significantly increased by substituting the countercation (NH4+) with the larger alkali ions Rb+ and Cs+. This constitutes a useful tactic for generating large aluminosilicate oligomers for surface characterization and ion-molecule reactivity studies.

  4. Hydration effects on the structural and vibrational properties of yttrium aluminosilicate glasses for in situ radiotherapy.

    PubMed

    Malik, Jahangir; Tilocca, Antonio

    2013-11-21

    The performances of silicate glasses as containment matrices or vectors of radioactive ions in nuclear waste storage and in situ radiotherapy are influenced by the effect of interstitial water on the glass durability. In order to assess how hydration determines changes to atomistic structural features which control the glass degradation, we have carried out molecular dynamics simulations of a typical yttrium aluminosilicate (YAS) glass employed in radiotherapy, incorporating different water contents. The analysis of the models allows us to discuss the way in which hydroxyl groups are distributed in the glass structure and modify or disrupt the aluminosilicate glass network. Hydration affects the silicate and aluminate connectivity to a different extent, resulting in a different degree of disruption (depolymerization) of the Si and Al network. The simulations also highlight a strong tendency of all hydrated compositions to form Y(3+)- and OH(-)-rich domains, separated from the aluminosilicate matrix. The implications of these structural effects for the durability and ion release behavior of the glass are discussed, as well as the vibrational signatures of the various hydrous species identified in the models. PMID:24206236

  5. Solubility and solution mechanisms of chlorine in aluminosilicate melts at high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Dalou, C.; Mysen, B. O.

    2012-12-01

    We address the effect of alkalies and aluminum on the solution behavior of Cl by combining solubility measurements of Cl and Raman data of Cl-bearing peralkaline aluminosilicate glasses (quenched melt). Six compositions along the join Na2Si3O7(NS3)-Na2(NaAl)3O7 and six compositions along the join K2Si3O7(KS3)-K2(KAl)3O7 were used. In order to isolate potential effects of Al/(Al+Si) from changes on melt polymerization, Al2O3 was exchanged with SiO2 in a charge-balanced form, NaAlO2 and KaAlO2 thus keeping approximately constant NBO/T (0.65 ± 0.02) for all melts (assuming Al3+ in 4-fold coordination in the melts). Starting materials were doped with 5wt% Cl in the form of PdCl2, which releases Cl2 as its gaseous phase during experiment. Samples were synthetized on piston-cylinder apparatus at 1600°C - 1.5 GPa. At the end of the experiments, Pd forms little spheres (1-2 μm) that for most part dissolves into the capsule. Chlorine oversaturation in the melts is ensured by the observation of bubbles in the quenched samples. The Cl solubility in Na-bearing systems is about twice that of the than in K-bearing system and may, therefore, be negatively correlated with ionic radius of the metal cation.. The solubility also decreases with Al/(Al+Si). In NS3 system, it decreases from 4.01 ± 0.13 wt% of Cl in Al-free systems to 1.87 ± 0.19 wt% of Cl for an Al/Al+Si ratio of 0.34. In KS3 system, this decrease is from 2.23 ± 0.08 wt% of Cl in Al-free systems to 0.62 ± 0.05 wt% of Cl for an Al/Al+Si ratio of 0.36. In Al-free systems, preliminary Raman data show the appearance of a peak around 465cm-1, that we assigned to alkali-Cl bonding. The intensity of this 465cm-1 peak increases with Al content confirming the role of Al in Cl solution mechanism.We also identify the molecular Cl peak at 1540cm-1. The peak can be detected only in Al-bearing melts. The Al substitution for Si results in increased abundance of three-dimensional cages on the melt structure into which molecular

  6. Sodium diethyldithiocarbamate

    Integrated Risk Information System (IRIS)

    Sodium diethyldithiocarbamate ; CASRN 148 - 18 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Non

  7. Sodium fluoroacetate

    Integrated Risk Information System (IRIS)

    Sodium fluoroacetate ; CASRN 62 - 74 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  8. Sodium azide

    Integrated Risk Information System (IRIS)

    Sodium azide ; CASRN 26628 - 22 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  9. Acifluorfen, sodium

    Integrated Risk Information System (IRIS)

    Acifluorfen , sodium ; CASRN 62476 - 59 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  10. Sodium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for sodium cyanide is included in the

  11. Synthetic peptides.

    PubMed

    Francis, M J

    1996-01-01

    Efforts to produce more stable and defined vaccines have concentrated on studying, in detail, the immune response to many infectious diseases in order to identify the antigenic sites on the pathogens that are involved in stimulating protective immumty. Armed with this knowledge, it is possible to mimic such sites by producing short chains of amino acids (peptides) and to use these as the basis for novel vaccines. The earliest documented work on peptide immunization is actually for a plant virus, tobacco mosaic virus. In 1963, Anderer (1) demonstrated that rabbit antibodies to an isolated hexapeptide fragment from the virus-coat protein coupled to bovine serum albumm would neutralize the infectious vn-us in culture. Two years later, he used a synthetically produced copy of the same peptide to confirm this observation. This was pioneering work, and it was over 10 years before the next example of a peptide that elicited antivirus antibody appeared following work by Sela and his colleagues (2) on a virus, MS2 bacteriophage, which infects bacteria. The emergence of more accessible techniques for sequencing proteins in 1977, coupled with the ability to synthesize readily peptides already developed in 1963, heralded a decade of intensive research into experimental peptide vaccines. The first demonstration that peptides could elicit protective immunity in vivo, in addition to neutralizing activity in vitro, was obtained using a peptide from the VP1 coat protein of foot-and-mouth disease virus (FMDV) in 1982, with the guinea pig as a laboratory animal model (3, 4). PMID:21359696

  12. Novel, inorganic composites using porous, alkali-activated, aluminosilicate binders

    NASA Astrophysics Data System (ADS)

    Musil, Sean

    Geopolymers are an inorganic polymeric material composed of alumina, silica, and alkali metal oxides. Geopolymers are chemical and fire resistant, can be used as refractory adhesives, and are processed at or near ambient temperature. These properties make geopolymer an attractive choice as a matrix material for elevated temperature composites. This body of research investigated numerous different reinforcement possibilities and variants of geopolymer matrix material and characterized their mechanical performance in tension, flexure and flexural creep. Reinforcements can then be chosen based on the resulting properties to tailor the geopolymer matrix composites to a specific application condition. Geopolymer matrix composites combine the ease of processing of polymer matrix composites with the high temperature capability of ceramic matrix composites. This study incorporated particulate, unidirectional fiber and woven fiber reinforcements. Sodium, potassium, and cesium based geopolymer matrices were evaluated with cesium based geopolymer showing great promise as a high temperature matrix material. It showed the best strength retention at elevated temperature, as well as a very low coefficient of thermal expansion when crystallized into pollucite. These qualities made cesium geopolymer the best choice for creep resistant applications. Cesium geopolymer binders were combined with unidirectional continuous polycrystalline mullite fibers (Nextel(TM) 720) and single crystal mullite fibers, then the matrix was crystallized to form cubic pollucite. Single crystal mullite fibers were obtained by the internal crystallization method and show excellent creep resistance up to 1400°C. High temperature flexural strength and flexural creep resistance of pollucite and polycrystalline/single-crystal fibers was evaluated at 1000-1400°C.

  13. Test Your Sodium Smarts

    MedlinePlus

    ... You may be surprised to learn how much sodium is in many foods. Sodium, including sodium chloride ... foods with little or no salt. Test your sodium smarts by answering these 10 questions about which ...

  14. Low sodium diet (image)

    MedlinePlus

    ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, or ... for you. Look for these words on labels: low-sodium, sodium-free, no salt added, sodium-reduced, or ...

  15. Calculation of the 13C NMR shieldings of the C0 2 complexes of aluminosilicates

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    1995-04-01

    13C NMR shieldings have been calculated using the random-phase-approximation, localized-orbital local-origins version of ab initio coupled Hartree-Fuck perturbation theory for CO 2 and and for several complexes formed by the reaction of CO 2 with molecular models for aluminosilicate glasses, H 3TOT'H3 3-n, T,T' = Si,Al. Two isomeric forms of the CO 2-aluminosilicate complexes have been considered: (1) "CO 2-like" complexes, in which the CO 2 group is bound through carbon to a bridging oxygen and (2) "CO 3-like" complexes, in which two oxygens of a central CO 3 group form bridging bonds to the two TH 3 groups. The CO 2-like isomer of CO 2-H 3SiOSiH 3 is quite weakly bonded and its 13C isotropic NMR shielding is almost identical to that in free CO 2. As Si is progressively replaced by Al in the - H terminated aluminosilicate model, the CO 2-like isomers show increasing distortion from the free CO 2 geometry and their 13C NMR shieldings decrease uniformly. The calculated 13C shielding value for H 3AlO(CO 2)AlH 3-2 is only about 6 ppm larger than that calculated for point charge stabilized CO 3-2. However, for a geometry of H 3SiO(CO 2) AlH 3-1, in which the bridging oxygen to C bond length has been artificially increased to that found in the - OH terminated cluster (OH) 3SiO(CO 2)Al(OH) 3-1, the calculated 13C shielding is almost identical to that for free CO 2. The CO 3-like isomers of the CO 2-aluminosili-cate complexes show carbonate like geometries and 13C NMR shieldings about 4-9 ppm larger than those of carbonate for all T,T' pairs. For the Si,Si tetrahedral atom pair the CO 2-like isomer is more stable energetically, while for the Si,Al and Al,Al cases the CO 3-like isomer is more stable. Addition of Na + ions to the CO 3-2 or H 3AlO(CO 2)AlH 3-2 complexes reduces the 13C NMR shieldings by about 10 ppm. Complexation with either Na + or CO 2 also reduces the 29Si NMR shieldings of the aluminosilicate models, while the changes in 27Al shielding with Na + or CO 2

  16. Development of a Composite Non-Electrostatic Surface Complexation Model Describing Plutonium Sorption to Aluminosilicates

    SciTech Connect

    Powell, B A; Kersting, A; Zavarin, M; Zhao, P

    2008-10-28

    Due to their ubiquity in nature and chemical reactivity, aluminosilicate minerals play an important role in retarding actinide subsurface migration. However, very few studies have examined Pu interaction with clay minerals in sufficient detail to produce a credible mechanistic model of its behavior. In this work, Pu(IV) and Pu(V) interactions with silica, gibbsite (Aloxide), and Na-montmorillonite (smectite clay) were examined as a function of time and pH. Sorption of Pu(IV) and Pu(V) to gibbsite and silica increased with pH (4 to 10). The Pu(V) sorption edge shifted to lower pH values over time and approached that of Pu(IV). This behavior is apparently due to surface mediated reduction of Pu(V) to Pu(IV). Surface complexation constants describing Pu(IV)/Pu(V) sorption to aluminol and silanol groups were developed from the silica and gibbsite sorption experiments and applied to the montmorillonite dataset. The model provided an acceptable fit to the montmorillonite sorption data for Pu(V). In order to accurately predict Pu(IV) sorption to montmorillonite, the model required inclusion of ion exchange. The objective of this work is to measure the sorption of Pu(IV) and Pu(V) to silica, gibbsite, and smectite (montmorillonite). Aluminosilicate minerals are ubiquitous at the Nevada National Security Site and improving our understanding of Pu sorption to aluminosilicates (smectite clays in particular) is essential to the accurate prediction of Pu transport rates. These data will improve the mechanistic approach for modeling the hydrologic source term (HST) and provide sorption Kd parameters for use in CAU models. In both alluvium and tuff, aluminosilicates have been found to play a dominant role in the radionuclide retardation because their abundance is typically more than an order of magnitude greater than other potential sorbing minerals such as iron and manganese oxides (e.g. Vaniman et al., 1996). The sorption database used in recent HST models (Carle et al., 2006

  17. Contribution of aluminas and aluminosilicates to the formation of PCDD/Fs on fly ashes.

    PubMed

    Potter, Phillip M; Dellinger, Barry; Lomnicki, Slawomir M

    2016-02-01

    Chlorinated aromatics undergo surface-mediated reactions with metal oxides to form Environmentally Persistent Free Radicals (EPFRs) which can further react to produce polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Previous work using laboratory-made fly ash surrogates composed of transition metal oxides deposited on silica powder has confirmed their ability to mimic fly ash in the production of PCDD/Fs. However, little is known about the propensity of aluminas and aluminosilicates, other components of fly ash, to form PCDD/Fs. A fly ash sample containing both alumina and mullite, an aluminosilicate, was tested for PCDD/F formation ability and compared to PCDD/F yields from the thermal degradation of 2-monochlorophenol (2-MCP) precursor over γ-alumina, α-alumina, and mullite. A packed-bed flow reactor was used to investigate the thermal degradation of 2-MCP over the various catalysts at 200-600 °C. Fly ash gave similar PCDD/F yields to surrogates made with similar transition metal content. γ-alumina, which is thermodynamically unfavorable, was very catalytically active and gave low PCDD/F yields despite a high destruction of 2-MCP. Mullite and α-alumina, the thermodynamically favorable form of alumina, yielded higher concentrations of dioxins and products with a higher degree of chlorine substitution than γ-alumina. The data suggest that certain aluminas and aluminosilicates, commonly found in fly ash, are active catalytic surfaces in the formation of PCDD/Fs in the post-flame cool zones of combustion systems and should be considered as additional catalytic surfaces active in the process. PMID:26615490

  18. Efficient adsorbents of nanoporous aluminosilicate monoliths for organic dyes from aqueous solution.

    PubMed

    El-Safty, Sherif A; Shahat, Ahmed; Awual, Md Rabiul

    2011-07-01

    Growing public awareness on the potential risk to humans of toxic chemicals in the environment has generated demand for new and improved methods for toxicity assessment and removal, rational means for health risk estimation. With the aim of controlling nanoscale adsorbents for functionality in molecular sieving of organic pollutants, we fabricated cubic Im3m mesocages with uniform entrance and large cavity pores of aluminosilicates as highly promising candidates for the colorimetric monitoring of organic dyes in an aqueous solution. However, a feasible control over engineering of three-dimensional (3D) mesopore cage structures with uniform entrance (~5 nm) and large cavity (~10 nm) allowed the development of nanoadsorbent membranes as a powerful tool for large-quantity and high-speed (in minutes) adsorption/removal of bulk molecules such as organic dyes. Incorporation of high aluminum contents (Si/Al=1) into 3D cubic Im3m cage mesoporous silica monoliths resulted in small, easy-to-use optical adsorbent strips. In such adsorption systems, natural surfaces of active acid sites of aluminosilicate strips strongly induced both physical adsorption of chemically responsive dyes and intraparticle diffusion into cubic Im3m mesocage monoliths. Results likewise indicated that although aluminosilicate strips with low Si/Al ratios exhibit distortion in pore ordering and decrease in surface area and pore volume, enhancement of both molecular converges and intraparticle diffusion onto the network surfaces and into the pore architectures of adsorbent membranes was achieved. Moreover, 3D mesopore cage adsorbents are reversible, offering potential for multiple adsorption assays.

  19. Contribution of aluminas and aluminosilicates to the formation of PCDD/Fs on fly ashes.

    PubMed

    Potter, Phillip M; Dellinger, Barry; Lomnicki, Slawomir M

    2016-02-01

    Chlorinated aromatics undergo surface-mediated reactions with metal oxides to form Environmentally Persistent Free Radicals (EPFRs) which can further react to produce polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Previous work using laboratory-made fly ash surrogates composed of transition metal oxides deposited on silica powder has confirmed their ability to mimic fly ash in the production of PCDD/Fs. However, little is known about the propensity of aluminas and aluminosilicates, other components of fly ash, to form PCDD/Fs. A fly ash sample containing both alumina and mullite, an aluminosilicate, was tested for PCDD/F formation ability and compared to PCDD/F yields from the thermal degradation of 2-monochlorophenol (2-MCP) precursor over γ-alumina, α-alumina, and mullite. A packed-bed flow reactor was used to investigate the thermal degradation of 2-MCP over the various catalysts at 200-600 °C. Fly ash gave similar PCDD/F yields to surrogates made with similar transition metal content. γ-alumina, which is thermodynamically unfavorable, was very catalytically active and gave low PCDD/F yields despite a high destruction of 2-MCP. Mullite and α-alumina, the thermodynamically favorable form of alumina, yielded higher concentrations of dioxins and products with a higher degree of chlorine substitution than γ-alumina. The data suggest that certain aluminas and aluminosilicates, commonly found in fly ash, are active catalytic surfaces in the formation of PCDD/Fs in the post-flame cool zones of combustion systems and should be considered as additional catalytic surfaces active in the process.

  20. Metallic nanoparticles and their medicinal potential. Part II: aluminosilicates, nanobiomagnets, quantum dots and cochleates.

    PubMed

    Loomba, Leena; Scarabelli, Tiziano

    2013-09-01

    Metallic miniaturization techniques have taken metals to nanoscale size where they can display fascinating properties and their potential applications in medicine. In recent years, metal nanoparticles such as aluminium, silicon, iron, cadmium, selenium, indium and calcium, which find their presence in aluminosilicates, nanobiomagnets, quantum dots (Q-dots) and cochleates, have caught attention of medical industries. The increasing impact of metallic nanoparticles in life sciences has significantly advanced the production techniques for these nanoparticles. In this Review, the various methods for the synthesis of nanoparticles are outlined, followed by their physicochemical properties, some recent applications in wound healing, diagnostic imaging, biosensing, assay labeling, antimicrobial activity, cancer therapy and drug delivery are listed, and finally their toxicological impacts are revised. The first half of this article describes the medicinal uses of two noble nanoparticles - gold and silver. This Review provides further information on the ability of aluminum, silicon, iron, selenium, indium, calcium and zinc to be used as nanoparticles in biomedical sciences. Aluminosilicates find their utility in wound healing and antibacterial growth. Iron-oxide nanoparticles enhance the properties of MRI contrast agents and are also used as biomagnets. Cadmium, selenium, tellurium and indium form the core nanostructures of tiny Q-dots used in cellular assay labeling, high-resolution cell imaging and biosensing. Cochleates have the bivalent nano ions calcium, magnesium or zinc imbedded in their structures and are considered to be highly effective agents for drug and gene delivery. The aluminosilicates, nanobiomagnets, Q-dots and cochleates are discussed in the light of their properties, synthesis and utility.

  1. DuraLith Alkali-Aluminosilicate Geopolymer Waste Form Testing for Hanford Secondary Waste

    SciTech Connect

    Gong, W. L.; Lutz, Werner; Pegg, Ian L.

    2011-07-21

    The primary objective of the work reported here was to develop additional information regarding the DuraLith alkali aluminosilicate geopolymer as a waste form for liquid secondary waste to support selection of a final waste form for the Hanford Tank Waste Treatment and Immobilization Plant secondary liquid wastes to be disposed in the Integrated Disposal Facility on the Hanford Site. Testing focused on optimizing waste loading, improving waste form performance, and evaluating the robustness of the waste form with respect to waste variability.

  2. Potential Sites for Ice Nucleation on Aluminosilicate Clay Minerals and Related Materials.

    PubMed

    Freedman, Miriam Arak

    2015-10-01

    Few aerosol particles in clouds nucleate the formation of ice. The surface sites available for nucleus formation, which can include surface defects and functional groups, determine in part the activity of an aerosol particle toward ice formation. Although ice nucleation on particles has been widely studied, exploration of the specific sites at which the initial germ forms has been limited, but is important for predicting the microphysical properties of clouds, which impact climate. This Perspective focuses on what is currently known about surface sites for ice nucleation on aluminosilicate clay minerals, which are commonly found in ice residuals, as well as related materials. PMID:26722881

  3. A coarse-graining approach for the proton complex in protonated aluminosilicates.

    PubMed

    Calero, S; Lobato, M D; García-Pérez, E; Mejías, J A; Lago, S; Vlugt, T J H; Maesen, T L M; Smit, B; Dubbeldam, D

    2006-03-30

    We have developed a computational framework for the adsorption of linear alkanes in protonated aluminosilicates. These zeolites contain trace amounts of water that form hydrated proton complexes. The presence of hydrated protons makes the simulations at the fully atomistic level difficult. Instead of constructing an elaborate and complex model, we show that an approach based on a coarse-graining of the proton-complex accurately describes the available experimental isotherms, Henry coefficients, heats of adsorption, and oxygen-proton distances. Our approach is supported by MP2 quantum mechanical simulations. The model gives remarkably good agreement with experimental data beyond the initial calibration set.

  4. Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

    NASA Astrophysics Data System (ADS)

    Zhang, Long; Liu, Peng

    2008-08-01

    The uniform polyaniline (PANI) nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conductivity of the PANI nanotubes was found to be 1.752 × 10-5 (Ω·cm)-1.

  5. Cooperative luminescence and absorption in ytterbium doped aluminosilicate glass optical fibres and preforms

    NASA Astrophysics Data System (ADS)

    Ryan, Tom G.; Jackson, Stuart D.

    2007-05-01

    The cooperative luminescence and absorption properties of Yb 3+ doped aluminosilicate glass optical fibres and preforms are investigated in detail. In accordance with previous investigations, both the visible cooperative luminescence and the infrared luminescence decay measurements have been resolved into a single exponential decay component. We show that for a glass with similar Yb 3+ dopant concentration but more Al 3+, the glass emits less visible luminescence. Absorption loss measurements completed on fibre samples revealed a broad absorption in the 350-500 nm range, which we propose is due to a combination of Yb 2+ absorption and cooperative absorption from Yb 3+ ion pairs.

  6. Potential Sites for Ice Nucleation on Aluminosilicate Clay Minerals and Related Materials.

    PubMed

    Freedman, Miriam Arak

    2015-10-01

    Few aerosol particles in clouds nucleate the formation of ice. The surface sites available for nucleus formation, which can include surface defects and functional groups, determine in part the activity of an aerosol particle toward ice formation. Although ice nucleation on particles has been widely studied, exploration of the specific sites at which the initial germ forms has been limited, but is important for predicting the microphysical properties of clouds, which impact climate. This Perspective focuses on what is currently known about surface sites for ice nucleation on aluminosilicate clay minerals, which are commonly found in ice residuals, as well as related materials.

  7. Direct observation of macrostructure formation of hierarchically structured meso-macroporous aluminosilicates with 3D interconnectivity by optical microscope.

    PubMed

    Lemaire, Arnaud; Rooke, Joanna Claire; Chen, Li-Hua; Su, Bao-Lian

    2011-03-15

    Hierarchically structured spongy meso-macroporous aluminosilicates with high tetrahedral aluminum content were synthesized from a mixture of single molecular alkoxide precursor, (sec-BuO)2-Al-O-Si(OEt)3, already containing Si-O-Al bonds, and a silica coreactant, tetramethoxysilane (TMOS). The spontaneous byproduct templated macroporous structure formation has been directly visualized using in situ high-resolution optical microscopy (OM), allowing the crucial observation of a microbubble dispersion which is directly correlated to the macrostructure observed by electronic microscopies (SEM and TEM). This discovery leads to a comparative study with meso-macroporous pure metal oxide and to a proposal of the formation mechanism of meso-macroporous aluminosilicates with 3D interconnectivity. The aluminosilicate phase/microbubbles emulsion is produced by a phase separation process occurring between the aluminosilicate nanoparticles and the liquid hydrolysis-condensation reaction byproducts (water, methanol, ethanol, and butanol). The use of alkoxysilane improves the heterocondensation rates between the highly reactive aluminum alkoxide part of the single precursor and added silica species but, above all, leads to the spontaneous generation of an unusual meso-macroporosity in alkaline media. The particles obtained at pH = 13.0 featured regular micrometer-sized macrospheres separated by very thin mesoporous walls and connected by submicrometric openings, providing a 3D interconnectivity. The slight increase in pH value to 13.5 induced significant modifications in morphology and textural properties due to the slower gelification process of the aluminosilicate phase, resulting in the formation of an aluminosilicate material constituted of 1-2 µm large independent hollow mesoporous spheres.

  8. Development of a New Ferrous Aluminosilicate Refractory Material for Investment Casting of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Yuan, Chen; Jones, Sam; Blackburn, Stuart

    2012-12-01

    Investment casting is a time-consuming, labour intensive process, which produces complex, high value-added components for a variety of specialised industries. Current environmental and economic pressures have resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Alumino-silicate based refractories are commonly used as both filler and stucco materials for ceramic shell production. A new ceramic material, norite, is now being produced based on ferrous aluminosilicate chemistry, having many potential advantages when used for the production of shell molds for casting aluminum alloy. This paper details the results of a direct comparison made between the properties of a ceramic shell system produced with norite refractories and a typical standard refractory shell system commonly used in casting industry. A range of mechanical and physical properties of the systems was measured, and a full-scale industrial casting trial was also carried out. The unique properties of the norite shell system make it a promising alternative for casting aluminum based alloys in the investment foundry.

  9. Aqueous dissolution, solubilities and thermodynamic stabilities of common aluminosilicate clay minerals: Kaolinite and smectites

    USGS Publications Warehouse

    May, Howard M.; Klnniburgh, D.G.; Helmke, P.A.; Jackson, M.L.

    1986-01-01

    Determinations of the aqueous solubilities of kaolinite at pH 4, and of five smectite minerals in suspensions set between pH 5 and 8, were undertaken with mineral suspensions adjusted to approach equilibrium from over- and undersaturation. After 1,237 days, Dry Branch, Georgia kaolinite suspensions attained equilibrium solubility with respect to the kaolinite, for which Keq = (2.72 ?? 0.35) ?? 107. The experimentally determined Gibbs free energy of formation (??Gf,2980) for the kaolinite is -3,789.51 ?? 6.60 kj mol-1. Equilibrium solubilities could not be determined for the smectites because the composition of the solution phase in the smectite suspensions appeared to be controlled by the formation of gibbsite or amorphous aluminum hydroxide and not by the smectites, preventing attempts to determine valid ??Gf0 values for these complex aluminosilicate clay minerals. Reported solubility-based ??Gf0 determinations for smectites and other variable composition aluminosilicate clay minerals are shown to be invalid because of experimental deficiencies and of conceptual flaws arising from the nature of the minerals themselves. Because of the variable composition of smectites and similar minerals, it is concluded that reliable equilibrium solubilities and solubility-derived ??Gf0 values can neither be rigorously determined by conventional experimental procedures, nor applied in equilibriabased models of smectite-water interactions. ?? 1986.

  10. The plumber's nightmare: a new morphology in block copolymer-ceramic nanocomposites and mesoporous aluminosilicates.

    PubMed

    Finnefrock, Adam C; Ulrich, Ralph; Toombes, Gilman E S; Gruner, Sol M; Wiesner, Ulrich

    2003-10-29

    A novel cubic bicontinuous morphology is found in polymer-ceramic nanocomposites and mesoporous aluminosilicates that are derived by an amphiphilic diblock copolymer, poly(isoprene-b-ethylene oxide) (PI-b-PEO), used as a structure-directing agent for an inorganic aluminosilicate. Small-angle X-ray scattering (SAXS) was employed to unambiguously identify the Im(-)3m crystallographic symmetry of the materials by fitting individual Bragg peak positions in the two-dimensional X-ray images. Structure factor calculations, in conjunction with results from transmission electron microscopy, were used to narrow the range of possible structures consistent with the symmetry and showed the plumber's nightmare morphology to be consistent with the data. The samples are made by deposition onto a substrate that imposes a strain field, generating a lattice distortion. This distortion is quantitatively analyzed and shown to have resulted in shrinkage of the crystallites by approximately one-third in a direction perpendicular to the substrate, in both as-made composites and calcined ceramic materials. Finally, the observation of the bicontinuous block-copolymer-derived hybrid morphology is discussed in the context of a pseudo-ternary morphology diagram and compared to existing studies of ternary phase diagrams of amphiphiles in a mixture of two solvents. The calcined mesoporous materials have potential applications in the fields of catalysis, separation technology, and microelectronics.

  11. Ordered hexagonal mesoporous aluminosilicates with low Si/Al ratio: synthesis, characterization, and catalytic application.

    PubMed

    Liu, Aifeng; Che, Hongwei; Liu, Chuanzhi; Fu, Quanrong; Jiang, Ruijiao; Wang, Cheng; Wang, Liang

    2014-06-01

    Ordered hexagonal mesoporous aluminosilicates with lower Si/Al ratio below 5 have been successfully synthesized via the co-assembly of preformed aluminosilicate precursors with Gemini surfactant [C12H25N+(CH3)2(CH2)6N+(CH3)2C12H25] x 2Br(-) as the template. Powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N2 adsorption-desorption isotherm measurements, Fourier transform infrared spectroscopy, 27Al nuclear magnetic resonance, thermogravimetric analysis, and temperature-programmed desorption of cyclohexylamine are employed to characterize the resulting samples. The phenol alkylation reaction is carried out to evaluate their catalytic performances. These studies indicate that the sample with a low Si/Al ratio of 3 still retains a highly ordered hexagonal mesoporous structure. And it also possesses the highest acidity of 0.96 mmol among the samples with lower Si/Al ratios below 5 due to its higher specific surface area together with more content of tetrahedrally coordinated Al in the framework. The catalytic tests confirm that the acidity of the samples plays a key role in determining their catalytic performances.

  12. Investigating the Heating of a Potassium-Doped Aluminosilicate Ion Source Using a 1 Micron Laser

    SciTech Connect

    Schmitt, R C; Meier, W R; Kwan, J W; Abbott, R P; Latkowski, J F

    2004-12-14

    The heavy ion fusion (HIF) program is interested in developing a high brightness ion source for high energy density physics (HEDP) experiments. One possible approach to obtaining higher brightness may be to raise the surface temperature of the ion source just prior to extraction. The current ion source material being studied is a layer of potassium-doped aluminosilicate bonded to a tungsten substrate. It is speculated that if the surface temperature of the source is raised above 1200 C (from a steady-state temperature of 900 C) for time periods on the order of 100's of nanoseconds, current densities of greater than 100 mA/cm{sup 2} of ions may be achievable. Typical aluminosilicate sources produce ion current densities (either K+ or Na+ ions) of {approx}10 mA/cm{sup 2} (at 1100 C). A number of heating methods might be possible, including lasers, diode arrays, and flash lamps. Here we assume laser heating. In this preliminary study, we used the LLNL RadHeat code to model the time-temperature history of the surface when hit by laser pulses and illustrate how RadHeat can be used to optimize the surface temperature response. Also of interest is the temperature history of the interface temperature between the ceramic and the metal layers. This is also investigated.

  13. Water solubility in calcium aluminosilicate glasses investigated by first principles techniques

    SciTech Connect

    Bouyer, Frederic; Geneste, Gregory; Ispas, Simona; Kob, Walter; Ganster, Patrick

    2010-12-15

    First-principles techniques have been employed to study the reactivity of water into a calcium aluminosilicate glass. In addition to the well known hydrolysis reactions Si-O-Si+H{sub 2}O{yields}Si-OH+Si-OH and Si-O-Al+H{sub 2}O{yields}Si-OH+Al-OH, a peculiar mechanism is found, leading to the formation of an AlO{sub 3}-H{sub 2}O entity and the breaking of Al-O-Si bond. In the glass bulk, most of the hydrolysis reactions are endothermic. Only a few regular sites are found reactive (i.e. in association with an exothermic reaction), and in that case, the hydrolysis reaction leads to a decrease of the local disorder in the amorphous vitreous network. Afterwards, we suggest that ionic charge compensators transform into network modifiers when hydrolysis occurs, according to a global process firstly suggested by Burnham in 1975. Our theoretical computations provide a more general model of the first hydrolysis steps that could help to understand experimental data and water speciation in glasses. -- Graphical Abstract: Reactivity within glass bulk: structures obtained after hydrolyses reactions (endothermic and exothermic processes) and mechanisms involving Si-OH, Al-OH, Si-OH-Al groups within aluminosilicates glasses (through ab initio molecular dynamics): formation of the Si-OH-Al entity coupled with an H exchange-Frederic Bouyer and Gregory Geneste. Display Omitted

  14. The effects of surface modification on the speciation of metal ions intercalated into aluminosilicates

    SciTech Connect

    Wasserman, S.R.; Giaquinta, D.M.; Yuchs, S.E.; Soderholm, L.

    1996-12-31

    Microporous aluminosilicates, including clay minerals and zeolites, are ion-exchange materials. In their most common forms, they have the ability to incorporate cationic species within their matrices. Because of this property, microporous aluminosilicates have been proposed as storage media for hazardous waste. In this paper the authors use X-ray absorption spectroscopy (XAS) to examine the structure of cations held within smectite clay minerals and to determine how modification of the surface of the clay using an organic monolayer affects the coordination of the stored cation. The effects of hydrothermal and thermal processing on the coordination of the ions contained within these systems are also investigated. The presence of the monolayer changes the surface of the clay from hydrophilic to hydrophobic. It inhibits the interlayer ions from exchanging freely into environmental water and reduces the leach rate of cations out of the clay by approximately a factor of 20. Significant changes are observed when these coated samples are treated under hydrothermal and thermal conditions. Reductions of uranium (VI), in the form of uranyl, and cupric ions occur. In addition, the uranium aggregates, forming small particles that appear similar to UO{sub 2}. Comparable conglomeration occurs with lead cations and with the reduced copper species.

  15. Compressibility of magnesium silicate glasses in comparison with those of aluminosilicate glasses

    NASA Astrophysics Data System (ADS)

    Kuryaeva, R. G.

    2013-10-01

    The refractive index of the Na2MgSi6O14 glass in the pressure range up to 6.0 GPa has been measured using a polarization-interference microscope and an apparatus with diamond anvils. The changes in relative density which characterize the compressibility of the glass have been estimated in the pressure range under investigation from the measured refractive indices within the framework of the theory of photoelasticity. The results have been compared with the data previously obtained for the NaAlSi3O8 and CaAl2Si6O16 glasses. A comparison of the changes in relative density of the aluminosilicate and magnesium silicate glasses has been demonstrated that the difference in the compressibility is not so much significant as should be expected from the replacement of network-forming ions by modifiers ions. Estimated by different methods the degree of depolymerization of the Na2MgSi6O14 glass (NBO/T ≅ 0.2) is compared to those for the aluminosilicate glasses. The decrease in the compressibility in the series NaAlSi3O8, CaAl2Si6O16, Na2MgSi6O14 glasses is in agreement with an increase of the degree of depolymerization in the same series.

  16. Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

    SciTech Connect

    Myers, Rupert J.; L'Hôpital, Emilie; Provis, John L.; Lothenbach, Barbara

    2015-02-15

    There exists limited information regarding the effect of temperature on the structure and solubility of calcium aluminosilicate hydrate (C–A–S–H). Here, calcium (alumino)silicate hydrate (C–(A–)S–H) is synthesised at Ca/Si = 1, Al/Si ≤ 0.15 and equilibrated at 7–80 °C. These systems increase in phase-purity, long-range order, and degree of polymerisation of C–(A–)S–H chains at higher temperatures; the most highly polymerised, crystalline and cross-linked C–(A–)S–H product is formed at Al/Si = 0.1 and 80 °C. Solubility products for C–(A–)S–H were calculated via determination of the solid-phase compositions and measurements of the concentrations of dissolved species in contact with the solid products, and show that the solubilities of C–(A–)S–H change slightly, within the experimental uncertainty, as a function of Al/Si ratio and temperature between 7 °C and 80 °C. These results are important in the development of thermodynamic models for C–(A–)S–H to enable accurate thermodynamic modelling of cement-based materials.

  17. Electromagnetic and Mechanical Properties of Silica-Aluminosilicates Plasma Sprayed Composite Coatings

    NASA Astrophysics Data System (ADS)

    Cipri, F.; Bartuli, C.; Valente, T.; Casadei, F.

    2007-12-01

    The physico-chemical and thermo-mechanical properties of aluminosilicate ceramics (high-melting point, low thermal expansion coefficient, excellent thermal shock resistance, low-density and good corrosion resistance) make this class of materials a good option for high-temperature structural applications. Al2O3-SiO2 compounds show an excellent refractory behavior allowing a wide use as wear-resistant thermal barrier coatings, in metallurgical and glass plants and in high temperature heat exchangers. Moreover, the low values of thermal expansion coefficient and of complex permittivity allow to extend the use of this ceramic for microelectronic devices, radome for antennas and electromagnetic windows for microwaves and infrared. The present article presents the results of an extensive experimental activity carried out to produce thick aluminosilicate coatings by plasma-spray technique. The APS deposition parameters were optimized on the basis of a surface response approach, as specified by design of experiments (DoE) methodologies. Samples were tested for phase composition, total porosity, microstructure, microhardness, deposition efficiency, fracture toughness, and modulus of rupture. Finally, coatings were characterized for their particularly interesting electromagnetic properties: complex permittivity was measured at microwave frequency using a network analyzer with wave guide.

  18. A HIGH CURRENT DENSITY LI+ ALUMINO-SILICATE ION SOURCE FOR TARGET HEATING EXPERIMENTS

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.

    2011-03-23

    The NDCX-II accelerator for target heating experiments has been designed to use a large diameter ({approx_equal} 10.9 cm) Li{sup +} doped alumino-silicate source with a pulse duration of 0.5 {micro}s, and beam current of {approx_equal} 93 mA. Characterization of a prototype lithium alumino-silicate sources is presented. Using 6.35mm diameter prototype emitters (coated on a {approx_equal} 75% porous tungsten substrate), at a temperature of {approx_equal} 1275 C, a space-charge limited Li{sup +} beam current density of {approx_equal} 1 mA/cm{sup 2} was measured. At higher extraction voltage, the source is emission limited at around {approx_equal} 1.5 mA/cm{sup 2}, weakly dependent on the applied voltage. The lifetime of the ion source is {approx_equal} 50 hours while pulsing the extraction voltage at 2 to 3 times per minute. Measurements show that the life time of the ion source does not depend only on beam current extraction, and lithium loss may be dominated by neutral loss or by evaporation. The life time of a source is around {ge} 10 hours in a DC mode extraction, and the extracted charge is {approx_equal} 75% of the available Li in the sample. It is inferred that pulsed heating may increase the life time of a source.

  19. Low sodium level

    MedlinePlus

    Low sodium level is a condition in which the amount of sodium (salt) in the blood is lower than normal. The ... Sodium is found mostly in the body fluids outside the cells. It is very important for maintaining ...

  20. Plant synthetic biology.

    PubMed

    Liu, Wusheng; Stewart, C Neal

    2015-05-01

    Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants.

  1. Potentiated clinoptilolite: artificially enhanced aluminosilicate reduces symptoms associated with endoscopically negative gastroesophageal reflux disease and nonsteroidal anti-inflammatory drug induced gastritis

    PubMed Central

    Potgieter, Wilna; Samuels, Caroline Selma; Snyman, Jacques Renè

    2014-01-01

    Purpose The cation exchanger, a potentiated clinoptilolite (Absorbatox™ 2.4D), is a synthetically enhanced aluminosilicate. The aim of this study was to evaluate the possible benefits of a potentiated clinoptilolite as a gastroprotective agent in reducing the severity of clinical symptoms and signs associated with 1) endoscopically negative gastroesophageal reflux disease (ENGORD) and 2) nonsteroidal anti-inflammatory drug (NSAID) medication. Methods and patients Two randomized, double-blind, placebo-controlled, pilot studies, the ENGORD and NSAID studies, were conducted. After initial negative gastroscopy, a total of 25 patients suffering from ENGORD were randomized to receive either placebo capsules or 750 mg Absorbatox twice daily for 14 days. The NSAID study recruited 23 healthy patients who received orally either 1,500 mg Absorbatox or placebo three times daily, plus 500 mg naproxen twice daily. Patients underwent gastroscopic evaluation of their stomach linings prior to and on day 14 of the study. Gastric biopsies were obtained and evaluated via the upgraded Sydney system, whereas visible gastric events and status of the gastric mucosa were evaluated via a 0–3 rating scale. During both studies, patients recorded gastric symptoms in a daily symptom diary. Results In the ENGORD study, patients who received the potentiated clinoptilolite reported a significant reduction (P≤0.05) in severity of symptoms including reduction in heartburn (44%), discomfort (54%), and pain (56%). Symptom-free days improved by 41% compared to the group who received placebo (not significant). This was over and above the benefits seen with the proton pump inhibitor. In the NSAID study, the reduction in gastric symptom severity was echoed in the group who received the potentiated clinoptilolite. Treatment with the potentiated clinoptilolite resulted in significant prevention (P≤0.05) of mucosal erosion severity as graded by the gastroenterologist. Conclusion Absorbatox is a

  2. Biaxial Q-shearing of 27Al 3QMAS NMR spectra: insight into the structural disorder of framework aluminosilicates.

    PubMed

    Kobera, Libor; Brus, Jiri; Klein, Petr; Dedecek, Jiri; Urbanova, Martina

    2014-01-01

    In this contribution, we present the application potentiality of biaxial Q-shearing of (27)Al 3QMAS NMR spectra in the analysis of structural defects of aluminium units in aluminosilicates. This study demonstrates that the combination of various shearing transformations of the recorded (27)Al 3QMAS NMR spectra enables an understanding of the broadening processes of the correlation signals of disordered framework aluminosilicates, for which a wide distribution of (27)Al MAS NMR chemical shifts and quadrupolar parameters (i.e., second-order quadrupolar splitting and quadrupole-induced chemical shifts) can be expected. By combining the suitably selected shearing transformation procedures, the mechanisms of the formation of local defects in aluminosilicate frameworks, including Al/Si substitution effects in the next-nearest neighbouring T-sites, variations in bond angles, and/or variations in the physicochemical nature of charge-balancing counter-ions, can be identified. The proposed procedure has been extensively tested on a range of model aluminosilicate materials (kyanite, γ-alumina, metakaolin, analcime, chabazite, natrolite, phillipsite, mordenite, zeolite A, and zeolite Y).

  3. [SYNTHETIC PEPTIDE VACCINES].

    PubMed

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  4. [From synthetic biology to synthetic humankind].

    PubMed

    Nouvel, Pascal

    2015-01-01

    In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed.

  5. Preparation and characterization of cesium-137 aluminosilicate pellets for radioactive source applications

    SciTech Connect

    Schultz, F.J.; Tompkins, J.A.; Haff, K.W.; Case, F.N.

    1981-07-01

    Twenty-seven fully loaded /sup 137/Cs aluminosilicate pellets were fabricated in a hot cell by the vacuum hot pressing of a cesium carbonate/montmorillonite clay mixture at 1500/sup 0/C and 570 psig. Four pellets were selected for characterization studies which included calorimetric measurements, metallography, scanning electron microscope and electron backscattering (SEM-BSE), electron microprobe, x-ray diffraction, and cesium ion leachability measurements. Each test pellet contained 437 to 450 curies of /sup 137/Cs as determined by calorimetric measurements. Metallographic examinations revealed a two-phase system: a primary, granular, gray matrix phase containing large and small pores and small pore agglomerations, and a secondary fused phase interspersed throughout the gray matrix. SEM-BSE analyses showed that cesium and silicon were uniformly distributed throughout both phases of the pellet. This indicated that the cesium-silicon-clay reaction went to completion. Aluminum homogeneity was unconfirmed due to the high background noise associated with the inherent radioactivity of the test specimens. X-ray diffraction analyses of both radioactive and non-radioactive aluminosilicate pellets confirmed the crystal lattice structure to be pollucite. Cesium ion quasistatic leachability measurements determined the leach rates of fully loaded /sup 137/Cs sectioned pollucite pellets to date to be 4.61 to 34.4 x 10/sup -10/ kg m/sup -2/s/sup -1/, while static leach tests performed on unsectioned fully loaded pellets showed the leach rates of the cesium ion to date to be 2.25 to 3.41 x 10/sup -12/ kg m/sup -2/s/sup -1/. The cesium ion diffusion coefficients through the pollucite pellet were calculated using Fick's first and second laws of diffusion. The diffusion coefficients calculated for three tracer level /sup 137/Cs aluminosilicate pellets were 1.29 x 10/sup -16/m/sup 2/s/sup -1/, 6.88 x 10/sup -17/m/sup 2/s/sup -1/, and 1.35 x 10/sup -17/m/sup 2/s/sup -1/, respectively.

  6. Danaparoid sodium.

    PubMed

    Acostamadiedo, J M; Iyer, U G; Owen, J

    2000-05-01

    Danaparoid sodium (Orgaran, Organon) is a heparinoid glycosamino-glycuronan antithrombotic agent approved for the prophylaxis of post-operative deep vein thrombosis (DVT), which may lead to pulmonary embolism (PE) in patients undergoing elective hip replacement surgery. Danaparoid is a low molecular weight heparinoid consisting of a mixture of heparan sulphate (84%), dermatan sulphate (12%) and small amounts of chondroitin sulphate (4%), whose antithrombotic activity has been well established. Its pharmacological effect is exerted primarily by inhibiting Factors Xa (FXa) and IIa (FIIa) at a ratio greater than heparin, with a minimal effect on platelet function. Danaparoid exhibits low cross-reactivity with heparin-induced antibodies when compared with heparin or low molecular weight heparins (LMWH), thereby making it an excellent choice for the management of heparin-induced thrombocytopenia (HIT). It has excellent bioavailability following s.c. injection. Danaparoid has little effect on routine coagulation tests (activated partial thromboplastin time [aPTT], prothrombin time [PT], and thrombin time [TT]). Patients with elevated serum creatinine should be monitored carefully. For its FDA approved indication (DVT prophylaxis during hip replacement surgery), its cost per day is approximately eight times more than LMWH. Even though monitoring is not routinely necessary according to the manufacturer for its approved indication, monitoring is frequently necessary when it is used in other clinical scenarios. Its higher cost than comparable therapies for DVT prophylaxis and the low availability of the FXa assay in most non-tertiary care hospitals has limited the widespread use of danaparoid. Danaparoid has been found to be effective in the treatment of HIT although this is an off label use, despite being the most frequent reason why danaparoid is used. PMID:11249517

  7. Functionalized synthetic clays designed for polymer-clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Chastek, Thuy Truong

    Polymer-clay nanocomposites have many advantageous properties such as their light weight, transparency, flame retardency, barrier properties, and low cost. Exfoliation of natural clays into commercially important non-polar polymers such as polystyrene (PS) and polypropylene (PP) melts has been limited due to the immiscibility of these polymers with highly polar clays. Current means of addressing this problem, such as treating clays with surfactants, has met with limited success. Motivated by the need for synthetic clays that can be dispersed and exfoliated in non-polar polymer melts without added compatibilizers, we synthesized lamellar silicates and aluminosilicates to act as clay analogs. The flexibility of the sol-gel syntheses allowed hexadecyl and isobutyl functional groups to be covalently attached to the surface of the clays. Incorporating a high content of octahedral aluminum also strengthened the clay layers. The strength and surface functionalities of the layered silicates improved exfoliation during melt blending with PS and PP. We studied the effects of clay layer composition (silicate and alumino-silicate), layer thickness, organic functional groups, aluminum coordination, and covalent linking of surfactants on the performance of the nanocomposites. The lamellar morphology was determined from XRD and TEM. Organic functionalization was determined with solid state NMR and IR spectroscopy. The synthetic clays were mixed with various solvents to help predict their miscibility with PS and PP. Composites were prepared with different molecular weight polymers, which subjected the clays to a wide range of shear stresses. The clays were also pretreated by mixing in a master batch or dispersing in an organic solvent. The effects of PS and PP molecular weight, master batch, and solvent dispersion on the exfoliation of synthetic clays in PS are examined. Rheology and TEM were used to observe the quality of exfoliation and the final aspect ratio of the clay layers

  8. Calcium-magnesium Aluminosilicate (CMAS) Interactions with Advanced Environmental Barrier Coating Material

    NASA Technical Reports Server (NTRS)

    Wiesner, Valerie L.; Bansal, Narottam P.

    2015-01-01

    Particulates, like sand and volcanic ash, threaten the development of robust environmental barrier coatings (EBCs) that protect next-generation silicon-based ceramic matrix composite (CMC) turbine engine components from harsh combustion environments during service. The siliceous particulates transform into molten glassy deposits of calcium-magnesium aluminosilicate (CMAS) when ingested by an aircraft engine operating at temperatures above 1200C. In this study, a sample of desert sand was melted into CMAS glass to evaluate high-temperature interactions between the sand glass and an advanced EBC material. Desert sand glass was added to the surface of hot-pressed EBC substrates, which were then heated in air at temperatures ranging from 1200C to 1500C. Scanning electron microscopy and X-ray energy-dispersive spectroscopy were used to evaluate microstructure and phase compositions of specimens and the CMASEBC interface after heat treatments.

  9. Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

    SciTech Connect

    Eppler, F.H.; Yim, M.S.

    1998-09-01

    Vitrification has been identified as one of the most viable waste treatment alternatives for nuclear waste disposal. Currently, the most popular glass compositions being selected for vitrification are the borosilicate family of glasses. Another popular type that has been around in glass industry is the soda-lime-silicate variety, which has often been characterized as the least durable and a poor candidate for radioactive waste vitrification. By replacing the boron constituent with a cheaper substitute, such as silica, the cost of vitrification processing can be reduced. At the same time, addition of network intermediates such as Al{sub 2}O{sub 3} to the glass composition increases the environmental durability of the glass. The objective of this study is to examine the ability of the soda-lime-aluminosilicate glass as an alternative vitrification tool for the disposal of radioactive waste and to investigate the sensitivity of product chemical durability to variations in composition.

  10. Fictive temperature-independent density and minimum indentation size effect in calcium aluminosilicate glass

    NASA Astrophysics Data System (ADS)

    Gross, T. M.; Tomozawa, M.

    2008-09-01

    Using the calcium aluminosilicate system a glass was developed that exhibits fictive temperature-independent density by creating an intermediate glass between normal and anomalous glasses. Normal glass, such as soda-lime silicate glass, exhibits decreasing density with increasing fictive temperature while anomalous glass, such as silica glass, exhibits increasing density with increasing fictive temperature. This intermediate glass composition was found to exhibit the minimum indentation size effect during indentation hardness testing. It appears that the indentation size effect is correlated with a deformation-induced fictive temperature increase, which is accompanied by a density change and hardness change in the vicinity of the indentation. It is suggested from these observations that indentation size effect originates from the energy required to create interfaces and defects such as shear bands, subsurface cracks, and point defects near the indenter-specimen boundary, which accompany the volume change.

  11. Composites of Polyindole nanowires within Silicate and Aluminosilicate hosts with distinct conductive properties

    NASA Astrophysics Data System (ADS)

    Juárez, J. M.; Gómez Costa, M. B.; Anunziata, O. A.

    2016-07-01

    Nanostructured silicate SBA-15 and aluminosilicate AlSBA-15 were synthesized in order to prepare polyindole composites. The Silica mesoporous materials were prepared by sol- gel method and alumination using post-synthesis technique and analysed by different methods (XRD, BET, TEM, and FTIR). Polyindole/host composites were prepared by in situ oxidative polymerization of pre-adsorbed indole, employing Cl3Fe as oxidant. TG, FTIR, BET, XRD, SEM and TEM were used to characterize the resulting composites. These studies show that the porous structures of the materials are preserved after polymerization, and polyindole is found within the porous channels. The composites have an electrical conductivity range between values higher than those of the pure chemically synthesized polyindole, close to those of the pure electrochemically synthesized polymer and lower than those of the pure chemically synthesized polymer, in the order of 10-8 S/cm.

  12. Mesoporous MCM-41 aluminosilicates as model silica-alumina catalysts: Spectroscopic characterization of the acidity

    SciTech Connect

    Di Renzo, F.; Chiche, B.; Fajula, F.; Viale, S.; Garrone, E.

    1996-12-31

    The synthesis procedure brings about a low threshold value for the surface concentration of Al species and renders MCM-41 a model system for the study of silica-alumina phases. On severely outgassed samples, two types of Lewis sites are present, differing in their protrusion from the surface, as well as Bronsted sites engaged in lateral H-bonding, evidenced by the interaction with NH{sub 3} and CO. The conversion of Lewis sites into Bronsted ones by water adsorption shows that the Bronsted species are Si(OH)Al, typical of zeolites, and Si-Al(OH)-Si, found in dealuminated zeolites. The flexibility of the amorphous framework accounts for the differences with zeolitic aluminosilicates.

  13. The effect of surface modification on the ion-exchange properties of layered aluminosilicates

    SciTech Connect

    Yuchs, S.E.; Wasserman, S.R.

    1996-10-01

    Layered aluminosilicates and clay type minerals have been shown to have varying degrees of ion-exchange capacity. In this paper, the ion-exchange capacities of untreated and surface modified montmorillonite clays will be discussed. The effects of extent of surface modification, type of modifier, and type of exchangeable ion will also be discussed. Physical properties, including X-ray diffraction, surface area measurements, XAS and EXAFS, of the modified and native materials will be compared. These surface modification reactions have been shown to yield novel materials with very low ion leachability. Various leach test results from several encapsulated metal ion-exchanged materials will be detailed. This surface modification method may yield materials suitable for intermediate-term storage of hazardous metal ions.

  14. Fictive temperature-independent density and minimum indentation size effect in calcium aluminosilicate glass

    SciTech Connect

    Gross, T. M.; Tomozawa, M.

    2008-09-15

    Using the calcium aluminosilicate system a glass was developed that exhibits fictive temperature-independent density by creating an intermediate glass between normal and anomalous glasses. Normal glass, such as soda-lime silicate glass, exhibits decreasing density with increasing fictive temperature while anomalous glass, such as silica glass, exhibits increasing density with increasing fictive temperature. This intermediate glass composition was found to exhibit the minimum indentation size effect during indentation hardness testing. It appears that the indentation size effect is correlated with a deformation-induced fictive temperature increase, which is accompanied by a density change and hardness change in the vicinity of the indentation. It is suggested from these observations that indentation size effect originates from the energy required to create interfaces and defects such as shear bands, subsurface cracks, and point defects near the indenter-specimen boundary, which accompany the volume change.

  15. Strong UV absorption and visible luminescence in ytterbium-doped aluminosilicate glass under UV excitation.

    PubMed

    Engholm, M; Norin, L; Aberg, D

    2007-11-15

    A broad visible luminescence band and characteristic IR luminescence of Yb(3+) ions are observed under UV excitation in ytterbium-doped aluminosilicate glass. Samples made under both oxidizing and reducing conditions are analyzed. A strong charge-transfer absorption band in the UV range is observed for glass samples containing ytterbium. Additional absorption bands are observed for the sample made under reducing conditions, which are associated with f-d transitions of divalent ytterbium. The visible luminescence band is attributed to 5d-4f emission from Yb(2+) ions, and the IR luminescence is concluded to originate from a relaxed charge-transfer transition. The findings are important to explain induced optical losses (photodarkening) in high-power fiber lasers. PMID:18026305

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  17. A facile strategy to recycle template P123 from mesoporous aluminosilicates by ultrasonic extraction.

    PubMed

    Jin, Jun-su; Cao, Li; Su, Guang-xun; Xu, Chun-yan; Zhang, Ze-ting; Gao, Xiong-hou; Liu, Hong-hai; Liu, Hong-tao

    2014-09-01

    High synthesis cost of mesoporous aluminosilicates (MA) limits their practical application. Recycling of copolymer template employed in preparation of MA is an effective way to reduce the synthesis cost. An ultrasonic extraction strategy for recycling of organic template P123 in MAs is reported. Effects of different extraction parameters on P123 recovery are investigated and the optimum conditions are obtained. 75.0% P123 is recovered from MAs within 10 min by one-step ultrasonication. Characterizations indicated that the resulting P123-free MA (MA-U) exhibits excellent properties compared with that of calcined products. Moreover, recovered P123 can be employed to synthesize high hydrothermally stable MA. This investigation provides a facile strategy to recycle P123 from MA.

  18. Nedocromil sodium (Tilade).

    PubMed

    Bartels, L A; Farrington, E

    1994-01-01

    Nedocromil sodium is a well-tolerated antiasthmatic agent for initial therapy in patients with mild or moderate asthma not well controlled with inhaled beta-2 agonists and/or where methylxanthines are indicated. Like cromolyn sodium, nedocromil sodium offers a potential alternative to inhaled corticosteroids as maintenance therapy in patients with mild or moderate asthma not adequately controlled by bronchodilators. Furthermore, cromolyn sodium and nedocromil sodium may also reduce the usage of corticosteroids and provide some additional symptom control in patients whose asthma is not suitably controlled by optimal doses of inhaled corticosteroids. Both nedocromil sodium and cromolyn sodium are more efficacious than placebo for controlling of asthma, however, few studies have compared the effectiveness of cromolyn versus nedocromil at this time. Further experience and comparison studies of nedocromil sodium with cromolyn sodium in children are required before the role of nedocromil sodium as maintenance treatment in young asthmatic patients can be defined.

  19. Energy Analysis of Aluminosilicate Zeolites with Comprehensive Ranges of Framework Topologies, Chemical Compositions, and Aluminum Distributions.

    PubMed

    Muraoka, Koki; Chaikittisilp, Watcharop; Okubo, Tatsuya

    2016-05-18

    The contents and locations of Al in the zeolite frameworks are one of the key factors determining the physicochemical properties of zeolites. Systematic evaluation of the characteristics of zeolites with a wide variety of framework topologies, a wide range of Si/Al ratios, and various locations of Al is of great significance, but very challenging due to the limitation of the realizable ranges of Al contents in zeolites as well as the limited information on the Al locations obtained from the current analytical techniques. Here, we report the systematic analysis of the energetics of aluminosilicate zeolites with 209 existing framework topologies at different Si/Al ratios using molecular mechanics. More than 43 000 initial structures were generated to give comprehensive views of the energetics of zeolites. The results coincide well with the structural knowledge obtained experimentally. It was revealed that the relation between the relative framework energies versus the Al contents varies in accordance with the topologies, suggesting that the relative stability of zeolites depends not only on the topologies, but also on the substituting contents of Al. For particular topologies with the same Al contents, in addition, comparisons between random and specific distributions of Al showed that zeolite with Al at a particular T site is energetically more stable than those with random distributions, suggesting the inherent influences of the Al locations. The contents and locations of Al in zeolites likely have a certain preference that may reflect the range of chemical compositions, the Al distributions, and consequently the physicochemical properties of realizable aluminosilicate zeolites. PMID:27097121

  20. Prospects and challenges of iron pyroelectrolysis in magnesium aluminosilicate melts near minimum liquidus temperature.

    PubMed

    Ferreira, N M; Kovalevsky, A V; Mikhalev, S M; Costa, F M; Frade, J R

    2015-04-14

    Although steel production by molten oxide electrolysis offers potential economic and environmental advantages over classic extractive metallurgy, its feasibility is far from being convincingly demonstrated, mainly due to inherent experimental difficulties exerted by harsh conditions and lack of knowledge regarding relevant mechanisms and physico-chemical processes in the melts. The present work was intended to demonstrate the concept of pyroelectrolysis at very high temperature near the minimum liquidus point of magnesium aluminosilicate, being conducted under electron-blocking conditions using yttria-stabilized zirconia cells, and to provide a new insight into electrochemistry behind this process. Significant current yields are possible for pyroelectrolysis performed in electron-blocking mode using a solid electrolyte membrane to separate the anode and the molten electrolyte. Parasitic electrochemical processes rise gradually as the concentration of iron oxide dissolved in the molten electrolytes is depleted, impairing faradaic efficiency. Reduction of silica to metallic silicon was identified as a significant contribution to those parasitic currents, among other plausible processes. Direct pyroelectrolysis without electron blocking was found much less plausible, due to major limitations on faradaic efficiency imposed by electronic leakage and insufficient ionic conductivity of the aluminosilicate melt. Ohmic losses may consume an excessive fraction of the applied voltage, thus failing to sustain the Nernst potential required for reduction to metallic iron. The results suggest the need for further optimization of the molten electrolyte composition to promote ionic conductivity and to suppress electronic transport contribution, possibly, by tuning the Al/Si ratio and altering the network-forming/modifying behaviour of the iron cations. PMID:25760633

  1. Molecular Biology of Insect Sodium Channels and Pyrethroid Resistance

    PubMed Central

    Dong, Ke; Du, Yuzhe; Rinkevich, Frank; Nomura, Yoshiko; Xu, Peng; Wang, Lingxin; Silver, Kristopher; Zhorov, Boris S.

    2015-01-01

    Voltage-gated sodium channels are essential for the initiation and propagation of the action potential in neurons and other excitable cells. Because of their critical roles in electrical signaling, sodium channels are targets of a variety of naturally occurring and synthetic neurotoxins, including several classes of insecticides. This review is intended to provide an update on the molecular biology of insect sodium channels and the molecular mechanism of pyrethroid resistance. Although mammalian and insect sodium channels share fundamental topological and functional properties, most insect species carry only one sodium channel gene, compared to multiple sodium channel genes found in each mammalian species. Recent studies showed that two posttranscriptional mechanisms, alternative splicing and RNA editing, are involved in generating functional diversity of sodium channels in insects. More than 50 sodium channel mutations have been identified to be responsible for or associated with knockdown resistance (kdr) to pyrethroids in various arthropod pests and disease vectors. Elucidation of molecular mechanism of kdr led to the identification of dual receptor sites of pyrethroids on insect sodium channels. Most of the kdr mutations appear to be located within or close to the two receptor sites. The accumulating knowledge of insect sodium channels and their interactions with insecticides provides a foundation for understanding the neurophysiology of sodium channels in vivo and the development of new and safer insecticides for effective control of arthropod pests and human disease vectors. PMID:24704279

  2. Evolvable synthetic neural system

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  3. Synthetic cathinone abuse

    PubMed Central

    Capriola, Michael

    2013-01-01

    The abuse of synthetic cathinones, widely known as bath salts, has been increasing since the mid-2000s. These substances are derivatives of the naturally occurring compound cathinone, which is the primary psychoactive component of khat. The toxicity of synthetic cathinones includes significant sympathomimetic effects, as well as psychosis, agitation, aggression, and sometimes violent and bizarre behavior. Mephedrone and methylenedioxypyrovalerone are currently the predominantly abused synthetic cathinones. PMID:23869180

  4. [SYNTHETIC PEPTIDE VACCINES].

    PubMed

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested. PMID:27145593

  5. A Novel Conversion Process for Waste Slag: The Preparation of Aluminosilicate Glass with Evaluation of the Dielectric Properties from Blast Furnace Slag

    NASA Astrophysics Data System (ADS)

    Li, Sheng; Huang, Sanxi; Liu, Hongting; Wu, Fengnian; Chang, Ziyuan; Yue, Yunlong

    2015-11-01

    In this paper, aluminosilicate glass was prepared from blast furnace slag and quartz sand. Fourier transform infrared, differential scanning calorimetry and density measurements were carried out to investigate the effects of SiO2 on the aluminosilicate glass network rigidity. The results indicate that glass structure would be enhanced if more SiO2 was introduced into the glass system. Meanwhile, both the glass transition temperature ( T g) and the glass crystallization temperature ( T c) increase slightly; the increase in density of the glass being further evidence of the enhancement in glass network rigidity. Dielectric measurements show that the dielectric constant and dielectric loss decrease with more SiO2. The properties of the prepared aluminosilicate glasses are comparable to those of E glass, indicating that blast furnace slags are suitable for producing aluminosilicate glass with low dielectric constant and dielectric loss.

  6. A thermochemical study of glasses and crystals along the joins silica-calcium aluminate and silica-sodium aluminate

    NASA Astrophysics Data System (ADS)

    Navrotsky, Alexandra; Peraudeau, Gilles; McMillan, Paul; Coutures, Jean-Pierre

    1982-11-01

    Enthalpies of solution in molten 2PbO · B 2O 3 at 985 K are reported for series of glasses xCa0.5AlO2-(1- x) SiO2 ( O ≤ x ≤ 0.99) and xNaAlO2-(1- x) SiO2 (0 ≤ x ≤ 0.56). The data are compared to values for the corresponding crystalline aluminosilicates and to preliminary data for systems containing KAlO 2 and Mg 0.5AlO 2. The enthalpies of mixing of glasses become more exothermic with increasing basicity of the mono- or divalent oxide. The tendency toward immiscibility on the silica-rich side, indicated by the shape of the heat of mixing curve between x = 0 and x = 0.4, is pronounced in the calcium aluminate system, but not in the sodium aluminate system. The shape of the heat of mixing curve, which is roughly symmetrical about x = 0.5, can be rationalized in terms of glass structure by considering essentially random substitution of Si and Al on a continuous three dimensional tetrahedral framework, with stabilization arising from electrostatic interactions between aluminum and the nonframework cation balancing the destabilizing effects arising from perturbation of the aluminosilicate framework by the nonframework cation. These trends are consistent with the variation of physical properties of aluminosilicate melts.

  7. Nepheline crystallization in boron-rich alumino-silicate glasses as investigated by multi-nuclear NMR, Raman, & Mössbauer spectroscopies

    SciTech Connect

    Mccloy, John S.; Washton, Nancy M.; Gassman, Paul L.; Marcial, Jose; Weaver, Jamie L.; Kukkadapu, Ravi K.

    2015-02-01

    A spectroscopic study was conducted on 6 complex simulant nuclear waste glasses using multi-nuclear NMR, Raman and Mössbauer spectroscopies to explore the role of glass-forming elements Si, Al, B, along with Na and Fe and to understand their connectivity with the goal of understanding melt structure precursors to deleterious feldspathoid nepheline-like crystals formation. NMR showed the appearance of two sites for Al, Si, and Na in the samples which crystallized significant amounts of nepheline, and B speciation changed, typically resulting in more B(IV) after nepheline crystallization. Raman spectroscopy suggested a major part of the glass structure is composed of metaborate chains or rings, thus significant numbers of non-bridging oxygens and a separation of the borate from the alumino-silicate network. Mössbauer combined with Fe redox chemical measurements showed that Fe plays a minor role in these glasses, mostly as Fe3+, but that iron oxide spinel forms with nepheline in all cases. Models of the glass network, speciation of B, and allocation of non-bridging oxygens were computed. The Yun-Dell-Bray model failed to predict the observed high concentration of NBO necessary to explain the metaborate features in the Raman spectra, and it largely over-estimated B(IV) fraction. The model assuming Na-Al-Si moieties and using experimental B(IV) fraction predicted a large amount of NBO consistent with Raman spectra. An alternative notation for appreciating the glass network is suggested and then used to investigate the changes the glass due to crystallization of sodium nepheline and the residual glass network. From a theoretical standpoint, it may be preferred to picture nuclear waste glasses by the Lebedev theory of glass structure where “microcrystallites” of ordered nuclei (or embryos) exist in the matrix of more disordered glass.

  8. Charge-transfer state excitation as the main mechanism of the photodarkening process in ytterbium-doped aluminosilicate fibres

    SciTech Connect

    Bobkov, K K; Rybaltovsky, A A; Vel'miskin, V V; Likhachev, M E; Bubnov, M M; Dianov, E M; Umnikov, A A; Gur'yanov, A N; Vechkanov, N N; Shestakova, I A

    2014-12-31

    We have studied photodarkening in ytterbium-doped fibre preforms with an aluminosilicate glass core. Analysis of their absorption and luminescence spectra indicates the formation of stable Yb{sup 2+} ions in the glass network under IR laser pumping at a wavelength λ = 915 nm and under UV irradiation with an excimer laser (λ = 193 nm). We have performed comparative studies of the luminescence spectra of the preforms and crystals under excitation at a wavelength of 193 nm. The mechanism behind the formation of Yb{sup 2+} ions and aluminium – oxygen hole centres (Al-OHCs), common to ytterbium-doped YAG crystals and aluminosilicate glass, has been identified: photoinduced Yb{sup 3+} charge-transfer state excitation. (optical fibres)

  9. Charge-transfer state excitation as the main mechanism of the photodarkening process in ytterbium-doped aluminosilicate fibres

    NASA Astrophysics Data System (ADS)

    Bobkov, K. K.; Rybaltovsky, A. A.; Vel'miskin, V. V.; Likhachev, M. E.; Bubnov, M. M.; Dianov, E. M.; Umnikov, A. A.; Gur'yanov, A. N.; Vechkanov, N. N.; Shestakova, I. A.

    2014-12-01

    We have studied photodarkening in ytterbium-doped fibre preforms with an aluminosilicate glass core. Analysis of their absorption and luminescence spectra indicates the formation of stable Yb2+ ions in the glass network under IR laser pumping at a wavelength λ = 915 nm and under UV irradiation with an excimer laser (λ = 193 nm). We have performed comparative studies of the luminescence spectra of the preforms and crystals under excitation at a wavelength of 193 nm. The mechanism behind the formation of Yb2+ ions and aluminium - oxygen hole centres (Al-OHCs), common to ytterbium-doped YAG crystals and aluminosilicate glass, has been identified: photoinduced Yb3+ charge-transfer state excitation.

  10. Variable Synthetic Capacitance

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L.

    1986-01-01

    Feedback amplifier circuit synthesizes electronically variable capacitance. Variable Synthetic Capacitor is amplifier circuit with follower/feedback configuration. Effective input capacitance depends on input set current. If synthetic capacitor is connected across resonant element of oscillator, oscillator frequency controlled via input set current. Circuit especially suitable for fine frequency adjustments of piezoelectric-crystal or inductor/capacitor resonant oscillators.

  11. Flux Decoupling and Chemical Diffusion in Redox Dynamics in Aluminosilicate Melts and Glasses (Invited)

    NASA Astrophysics Data System (ADS)

    Cooper, R. F.

    2010-12-01

    Measurements of redox dynamics in silicate melts and glasses suggest that, for many compositions and for many external environments, the reaction proceeds and is rate-limited by the diffusive flux of divalent-cation network modifiers. Application of ion-backscattering spectrometry either (i) on oxidized or reduced melts (subsequently quenched before analysis) or (ii) on similarly reacted glasses, both of basalt-composition polymerization, demonstrates that the network modifiers move relative to the (first-order-rigid) aluminosilicate network. Thus, the textures associated with such reactions are often surprising, and frequently include metastable or unstable phases and/or spatial compositional differences. This response is only possible if the motion of cations can be decoupled from that of anions. In many cases, decoupling is accomplished by the presence in the melt/glass of transition-metal cations, whose heterovalency creates distortions in the electronic band structure resulting in electronic defects: electron “holes” in the valence band or electrons in the conduction band. (The prevalence of holes or electrons being a function of bulk chemistry and oxygen activity.) These electronic species make the melt/glass a “defect semiconductor.” Because (a) the critical issue in reaction dynamics is the transport coefficient (the product of species mobility and species concentration) and (b) the electronic species are many orders of magnitude more mobile than are the ions, very low concentrations of transition-metal ions are required for flux decoupling. For example, 0.04 at% Fe keeps a magnesium aluminosilicate melt/glass a defect semiconductor down to 800°C [Cook & Cooper, 2000]. Depending on composition, high-temperature melts can see ion species having a high-enough transport coefficient to allow decoupling, e.g., alkali cations in a basaltic melt [e.g., Pommier et al., 2010]. In this presentation, these ideas will be illustrated by examining redox dynamics

  12. Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX-II)

    SciTech Connect

    LBNL; Roy, P.K.; Greenway, W.; Kwan, J.W.; Seidl, P.A.; Waldron, W.

    2011-04-20

    To heat targets to electron-volt temperatures for the study of warm dense matter with intense ion beams, low mass ions, such as lithium, have an energy loss peak (dE/dx) at a suitable kinetic energy. The Heavy Ion Fusion Sciences (HIFS) program at Lawrence Berkeley National Laboratory will carry out warm dense matter experiments using Li{sup +} ion beam with energy 1.2-4 MeV in order to achieve uniform heating up to 0.1-1 eV. The accelerator physics design of Neutralized Drift Compression Experiment (NDCX-II) has a pulse length at the ion source of about 0.5 {micro}s. Thus for producing 50 nC of beam charge, the required beam current is about 100 mA. Focusability requires a normalized (edge) emittance {approx}2 {pi}-mm-mrad. Here, lithium aluminosilicate ion sources, of {beta}-eucryptite, are being studied within the scope of NDCX-II construction. Several small (0.64 cm diameter) lithium aluminosilicate ion sources, on 70%-80% porous tungsten substrate, were operated in a pulsed mode. The distance between the source surface and the mid-plane of the extraction electrode (1 cm diameter aperture) was 1.48 cm. The source surface temperature was at 1220 C to 1300 C. A 5-6 {micro}s long beam pulsed was recorded by a Faraday cup (+300 V on the collector plate and -300 V on the suppressor ring). Figure 1 shows measured beam current density (J) vs. V{sup 3/2}. A space-charge limited beam density of {approx}1 mA/cm{sup 2} was measured at 1275 C temperature, after allowing a conditioning time of about {approx} 12 hours. Maximum emission limited beam current density of {ge} 1.8mA/cm{sup 2} was recorded at 1300 C with 10-kV extractions. Figure 2 shows the lifetime of two typical sources with space-charge limited beam current emission at a lower extraction voltage (1.75 kV) and at temperature of 1265 {+-} 7 C. These data demonstrate a constant, space-charge limited beam current for 20-50 hours. The lifetime of a source is determined by the loss of lithium from the alumino-silicate

  13. Docusate Sodium and Pregnancy

    MedlinePlus

    ... live chat Live Help Fact Sheets Share Docusate Sodium Friday, 01 April 2016 In every pregnancy, a ... This sheet talks about whether exposure to docusate sodium may increase the risk for birth defects over ...

  14. Diclofenac sodium overdose

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002630.htm Diclofenac sodium overdose To use the sharing features on this page, please enable JavaScript. Diclofenac sodium is a prescription medicine used to relieve pain ...

  15. Sodium Ferric Gluconate Injection

    MedlinePlus

    Sodium ferric gluconate injection is used to treat iron-deficiency anemia (a lower than normal number of ... are also receiving the medication epoetin (Epogen, Procrit). Sodium ferric gluconate injection is in a class of ...

  16. Fractional excretion of sodium

    MedlinePlus

    FE sodium; FENa ... to a lab. There, they are examined for salt (sodium) and creatinine levels. Creatinine is a chemical waste ... your normal foods with a normal amount of salt, unless otherwise instructed by your health care provider. ...

  17. An empirical model to estimate density of sodium hydroxide solution: An activator of geopolymer concretes

    NASA Astrophysics Data System (ADS)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2016-02-01

    Geopolymer concrete is zero-Portland cement concrete containing alumino-silicate based inorganic polymer as binder. The polymer is obtained by chemical activation of alumina and silica bearing materials, blast furnace slag by highly alkaline solutions such as hydroxide and silicates of alkali metals. Sodium hydroxide solutions of different concentrations are commonly used in making GPC mixes. Often, it is seen that sodium hydroxide solution of very high concentration is diluted with water to obtain SHS of desired concentration. While doing so it was observed that the solute particles of NaOH in SHS tend to occupy lower volumes as the degree of dilution increases. This aspect is discussed in this paper. The observed phenomenon needs to be understood while formulating the GPC mixes since this influences considerably the relationship between concentration and density of SHS. This paper suggests an empirical formula to relate density of SHS directly to concentration expressed by w/w.

  18. Production and short-term of synthetic seeds from encapsulated begonia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic seeds were formed from in vitro grown Begonia (cvs ‘Sweetheart Mix’ and ‘Baby Wing White’) shoot tips using 3% sodium alginate in Murashige and Skoog (1962) medium (MS) salt solution as the gel matrix and 100 mM calcium chloride for complexation. Synthetic seed formation was achieved by re...

  19. Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W

    2012-03-05

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm2 have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm2, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

  20. Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.

    2012-04-01

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm2 have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm2, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

  1. The effect of TiO2/aluminosilicate nanocomposite additives on the mechanical and thermal properties of polyacrylic coatings

    NASA Astrophysics Data System (ADS)

    Nosrati, Rahimeh; Olad, Ali

    2015-12-01

    The commercial grade polyacrylic latex was modified in order to prepare a mechanical and thermal improved coating. TiO2/Ag-exchanged-aluminosilicate nanocomposites with montmorillonite, zeolite-A and clinoptilolite aluminosilicates were prepared and used as additive in the matrix of polyacrylic latex to achieve a coating with proper mechanical and thermal properties. X-ray diffraction patterns and FESEM were used to characterize the composition, structure, and morphology of the nanocomposite additives. Polyacrylic coatings modified by TiO2/Ag-exchanged-aluminosilicate nanocomposite additives showed higher adhesion strength and hardness compared to unmodified commercial grade polyacrylic coatings. Differential Scanning Calorimetry (DSC) analysis showed lower glass transition temperature for modified polyacrylic coatings than that of unmodified polyacrylic coatings. The tensile tests were also carried out for unmodified and modified polyacrylic coatings. According to the results, the modified polyacrylic based coating with TiO2/Ag-exchanged-clinoptilolite nanocomposite additive was the best coating considering most of useful properties.

  2. The selective adsorption of tellurium in the aluminosilicate regions of AFI- and MOR-type microporous crystals.

    PubMed

    Kodaira, Tetsuya; Ikeda, Takuji

    2014-10-01

    Attempts have been made to load tellurium (Te) atoms into the one-dimensional nano-channels of microporous crystals of aluminophosphate AlPO4-5 and of aluminosilicate mordenites of the Na(+) form (Na-MOR) and the H(+)-form (H-MOR) at 673 K. The density of the atoms adsorbed was in the sequence 0 ∼ AlPO4-5 ≪ H-MOR < Na-MOR. AlPO4-5 provides a shallow potential of periodical charge fluctuation for Te atoms, from the alternate ordering of Al and P atoms through O atoms. Mordenite offers a sufficiently strong potential for Te adsorption, but the magnitude varies with the type of cation. Dipoles between framework AlO2(-) anion sites and their Na(+) counter-ions in Na-MOR provide a stronger potential than the Brønsted acid points in H-MOR. The adsorption of Te atoms in the silico-aluminophosphate SAPO-5 was between that of AlPO4-5 and H-MOR, leading us to suspect that Te atoms are selectively adsorbed in the aluminosilicate regions accompanying the Brønsted acid points distributed in the major aluminophosphate network. The aluminosilicate regions in SAPO-5 are below 500 nm in size and are distributed throughout a single crystal.

  3. Synthesis and Structural Characterization of the Aluminosilicate LZ-135, a Zeolite Related to ZSM-10

    SciTech Connect

    McCusker, Lynne B.; Baerlocher, Christian; Wilson, Stephen T.; Broach, Robert W.

    2009-09-02

    The aluminosilicate LZ-135 was one of the first zeolites to be prepared in the presence of two or more organic structure-directing agents (in this case, Me{sub 4}N{sup +} (TMA) and Et{sub 4}N{sup +} (TEA)) and was patented 20 years ago. However, the material was polycrystalline, and at the time, its aluminosilicate framework structure could not be determined. In view of the fact that methods of structure determination from powder diffraction data have developed considerably in the meantime, a fresh analysis of the problem was undertaken. High-resolution synchrotron powder diffraction data were collected on a calcined sample of LZ-135 (as synthesized composition ca. |Na{sub 26}TMA{sub 6}|[Si{sub 76}Al{sub 32}O{sub 216}]), and the new powder charge-flipping structure-solution algorithm was applied. The framework structure (P6{sub 3}/mmc; a = 31.3830(2) {angstrom}, c = 7.6513(1) {angstrom}) was revealed immediately, and then the positions of the Na{sup +} ions and a few water molecules were located in a series of difference electron density maps. The [001] projection of the framework structure is identical to that of ZSM-10 (P6{sub 3}/mmm), but the (up-down) orientations of the (Si,Al) tetrahedra, and therefore their connectivities, are different, and this leads to a distinctly different topology with two 1-dimensional, 12-ring channel systems with effective pore widths of 7.2 and 6.5 {angstrom}. The new framework has been assigned the framework type code LTF by the International Zeolite Association. The framework structures of LZ-135 and ZSM-10 are related to one another in the same way as are those of mazzite and zeolite L. Approximately 27.5 Na{sup +} ions were located in six different sites, and all are coordinated to oxygen atoms of the framework. Twelve H{sub 2}O molecules per unit cell are associated with one of the Na{sup +} ion positions, where they serve to complete an octahedral coordination geometry around the ion, and 5.2 are located in the larger of the

  4. Alkali aluminosilicate melts and glasses: structuring at the middle range order of amorphous matter

    NASA Astrophysics Data System (ADS)

    Le Losq, C.; neuville, D. R.

    2012-12-01

    Rheological properties of silicate melts govern both magma ascension from the mantle to the surface of the earth and volcanological eruptions styles and behaviours. It is well known that several parameters impact strongly these properties, such as for instance the temperature, pressure, chemical composition and volatiles concentration, finally influencing eruptive behaviour of volcanoes. In this work, we will focus on the Na2O-K2O-Al2O3-SiO2 system, which is of a prime importance because it deals with a non-negligible part of natural melts, like for instance the Vesuvius (Italy) or Erebus (Antartica) magmas. In an oncoming paper in Chemical Geology (Le Losq and Neuville, 2012), we have communicated results of the study of mixing Na-K in tectosilicate melts containing a high concentration of silica (≥75mol%). In the present communication, we will enlarge this first point of view to tectosilicate melts presenting a lower silica concentration. We will first present our viscosity data, and then the Adam and Gibbs theory that allows theoretically modelling Na-K mixing in aluminosilicate melts by using the so-called "mixed alkali effect". On the basis of the rheological results, the Na-K mixing cannot be explained with the ideal "mixed alkali effect", which involves random exchange of Na-K cationic pairs. To go further and as rheological properties are directly linked with structural properties, we will present our first results obtained by Raman and NMR spectroscopy. These last ones provide important structural pieces of information on the polymerization state of glasses and melts, and also on the environment of tetrahedrally coordinated cations. Rheological and structural results all highlight that Na and K are not randomly distributed in aluminosilicate glasses and melts networks. Na melts present a network with some channels and a non-random distribution of Al and Si. K networks are different. They also present a non-random distribution of Al and Si, but in two sub

  5. 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.

  6. Saga of synthetic rubber

    SciTech Connect

    Solo, R.A.

    1980-04-01

    The proposal to establish an Energy Mobilization Board and a synthetic fuels industry is reminiscent of World War II efforts to produce synthetic rubber. To avoid the mistakes made in the earlier effort, Mr. Solo suggests that the synthetic-fuel program should (1) use a more-successful technological development project as a model; (2) commit public funding and not rely on profit-oriented private enterprise; and (3) avoid entrusting social planning to single-purpose entities that have not been sensitive to social values. (DCK)

  7. Synthetic Base Fluids

    NASA Astrophysics Data System (ADS)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  8. Building synthetic memory

    PubMed Central

    Inniss, Mara C.; Silver, Pamela A.

    2013-01-01

    Synopsis Cellular memory – conversion of a transient signal into a sustained response – is a common feature of biological systems. Synthetic biologists aim to understand and reengineer such systems in a reliable and predictable manner. Synthetic memory circuits have been designed and built in vitro and in vivo based on diverse mechanisms such as oligonucleotide hybridization, recombination, transcription, phosphorylation, and RNA editing. Thus far, building these circuits has helped us explore the basic principles required for stable memory and ask novel biological questions. Here we discuss strategies for building synthetic memory circuits, their use as research tools, and future applications of these devices in medicine and industry. PMID:24028965

  9. Requiem for synthetic fuels

    SciTech Connect

    Myers, R.

    1982-01-27

    US plans to launch a synthetic fuels industry revive whenever a price or supply crisis occurs, but industrial hopes descend as soon as the short-term market begins improving in terms of real prices. The capital requirements of a synthetic fuels project combined with fears of a noncompetitive product have caused several major oil companies to scale down or cancel their plans. In the author's view, the Reagan administration's hands-off policy and false sense of security from the current oil supply glut have further discouraged industry. The Synthetic Fuels Corporation has been slow to organize, and appears to be favoring small-size plants. (DCK)

  10. In situ structural analysis of calcium aluminosilicate glasses under high pressure

    NASA Astrophysics Data System (ADS)

    Muniz, R. F.; de Ligny, D.; Martinet, C.; Sandrini, M.; Medina, A. N.; Rohling, J. H.; Baesso, M. L.; Lima, S. M.; Andrade, L. H. C.; Guyot, Y.

    2016-08-01

    In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH--free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ({ν\\text{B}} [T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q n species to Q n-1. In the case of Al-rich glass, the Al in the smallest Q n units evolved from tetrahedral to higher-coordinated Al ([5]Al and [6]Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

  11. In situ structural analysis of calcium aluminosilicate glasses under high pressure

    NASA Astrophysics Data System (ADS)

    Muniz, R. F.; de Ligny, D.; Martinet, C.; Sandrini, M.; Medina, A. N.; Rohling, J. H.; Baesso, M. L.; Lima, S. M.; Andrade, L. H. C.; Guyot, Y.

    2016-08-01

    In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH‑-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ({ν\\text{B}} [T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q n species to Q n‑1. In the case of Al-rich glass, the Al in the smallest Q n units evolved from tetrahedral to higher-coordinated Al ([5]Al and [6]Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

  12. Synthesis and Properties of a Barium Aluminosilicate Solid Oxide Fuel Cell Glass-Ceramic Sealant

    SciTech Connect

    Meinhardt, Kerry D.; Kim, Dong-Sang; Chou, Y. S.; Weil, K. Scott

    2008-07-15

    A series of barium aluminosilicate glasses modified with CaO and B2O3, were prepared and evaluated with respect to their suitability in sealing planar solid oxide fuel cells (SOFCs). At a target operating temperature of 750ºC, the long-term CTE of one particular composition (35 mol% BaO, 15 mol% CaO, 10 mol% B2O3, 5 mol% Al2O3, bal. SiO2) was found to be particularly stable, due to devitrification to a mixture of glass and ceramic phases. This sealant composition exhibits minimal chemical interaction with the yttria-stabilized zirconia electrolyte, yet forms a strong bond with this material. Interactions with metal components were found to be more extensive and depended on the composition of the metal oxide scale that formed during sealing. Generally alumina-scale formers exhibited a more compact reaction zone with the glass than chromia-scale forming alloys. Mechanical measurements conducted on the bulk glass-ceramic and on seals formed using these materials indicate that the sealant is anticipated to display adequate long-term strength for most conventional stationary SOFC applications.

  13. Atomic Structure of a Cesium Aluminosilicate Geopolymer: A Pair Distribution Function Study

    SciTech Connect

    Bell, J.; Sarin, P; Provis, J; Haggerty, R; Driemeyer, P; Chupas, P; van Deventer, J; Kriven, W

    2008-01-01

    The atomic pair distribution function (PDF) method was used to study the structure of cesium aluminosilicate geopolymer. The geopolymer was prepared by reacting metakaolin with cesium silicate solution followed by curing at 50C for 24 h in a sealed container. Heating of Cs-geopolymer above 1000C resulted in formation of crystalline pollucite (CsAlSi{sub 2}O{sub 6}). PDF refinement of the pollucite phase formed displayed an excellent fit over the 10-30 {angstrom} range when compared with a cubic pollucite model. A poorer fit was attained from 1-10 {angstrom} due to an additional amorphous phase present in the heated geopolymer. On the basis of PDF analysis, unheated Cs-geopolymer displayed structural ordering similar to pollucite up to a length scale of 9 {angstrom}, despite some differences. Our results suggest that hydrated Cs{sup +} ions were an integral part of the Cs-geopolymer structure and that most of the water present was not associated with Al-OH or Si-OH bonds.

  14. Synthesis, characterization, and mercury adsorption properties of hybrid mesoporous aluminosilicate sieve prepared with fly ash

    NASA Astrophysics Data System (ADS)

    Liu, Minmin; Hou, Li-an; Xi, Beidou; Zhao, Ying; Xia, Xunfeng

    2013-05-01

    A novel hybrid mesoporous aluminosilicate sieve (HMAS) was prepared with fly ash and impregnated with zeolite A precursors. This improved the mercury adsorption of HMAS compared to original MCM-41. The HMAS was characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FTIR) analysis, transmission electron microscopy (TEM) images and 29Si and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectra. These showed that the HMAS structure was still retained after impregnated with zeolite A. But the surface area and pore diameter of HMAS decreased due to pore blockage. Adsorption of mercury from aqueous solution was studied on untreated MCM-41and HMAS. The mercury adsorption rate of HMAS was higher than that of origin MCM-41. The adsorption of mercury was investigated on HMAS regarding the pH of mercury solution, initial mercury concentration, and the reaction temperature. The experimental data fit well to Langmuir and Freundlich isotherm models. The Dublin-Radushkevich isotherm and the characterization show that the mercury adsorption on HMAS involved the ion-exchange mechanisms. In addition, the thermodynamic parameters suggest that the adsorption process was endothermic in nature. The adsorption of mercury on HMAS followed the first order kinetics.

  15. Chemical Interactions of Barium-Calcium-Aluminosilicate Based Sealing Glasses with Oxidation Resistant Alloys

    SciTech Connect

    Yang, Z Gary ); Stevenson, Jeffry W. ); Meinhardt, Kerry D. )

    2003-04-04

    In most planar SOFC stack designs, the interconnect, which is typically made from an oxidation resistant alloy, potentially including austenitic chromia-forming, ferritic chromia-forming, and alumina-forming alloys, has to be hermitically sealed to its adjacent components, usually by a sealing glass. To maintain the structural stability and minimize the degradation of stack performance, the sealing glass must be chemically compatible with the alloy used for the interconnect. In this work, Nicrofer6025, AISI446 and a Fecralloy were selected as examples of austenitic chromia-forming, ferritic chromia-forming, and alumina-forming alloys, respectively. Their chemical compatibility with a barium-calcium-aluminosilicate (BCAS) based glass, specifically developed as a sealant in SOFC stacks, was evaluated. It was found that the BCAS sealing glass interacted chemically with both the chromia-forming alloys and the alumina-forming alloys. The extent and nature of the interactions and their final products depended on the matrix alloy compositions, the exposure conditions and/or proximity of the glass/alloy interface to the ambient air. These interactions and their mechanisms will be discussed with the assistance of thermodynamic modeling.

  16. Chemical Compatibility of Barium-Calcium-Aluminosilicate Based Sealing Glasses with Heat Resistant Alloys

    SciTech Connect

    Yang, Z Gary; Weil, K. Scott; Meinhardt, Kerry D.; Stevenson, Jeffry W.; Paxton, Dean M.; Xia, Gordon; Kim, Dong-Sang

    2003-09-15

    Over the past several years, advances in the design and fabrication of planar SOFCs have led to a steady reduction in the temperatures necessary for their operation. Consequently, it appears more realistic now to use low cost heat resistant alloys for interconnect sub-components in the SOFC stack. Considering these materials requirements, heat resistant alloys, which overall demonstrate oxidation resistance at elevated temperatures, could be potential candidates. Overall, the heat resistant alloys of interest may include superalloys and the stainless steels. Depending whether a chromia or alumina scale forms on the alloy surface for protection, these heat resistant alloys can be also classified into chromia or alumina formers, repetitively. To help screening alloys and understanding the interface of sealing glass, a couple of alloy compositions have been carefully chosen as a reprehensive of different groups of alloys for the study on their chemical compatibility with a barium-aluminosilicate base glass. These alloys selected are AL 29-4, Nicrofer 6025, and Fecralloy, representing chromia forming stainless steels, superalloys and alumina formers, respectively. Results of chemical and microstructural analyses on sealing glass interfaces with different alloys will be presented, and accordingly, the applicability of alloys in terms of sealing glass chemical compatibility will be discussed. Possible means of modification on alloys for an improved applicability will be elaborated as well.

  17. Chemical Compatibility of Barium-Calcium-Aluminosilicate Based Sealing Glasses with Heat Resistant Alloys

    SciTech Connect

    Yang, Zhenguo; Weil, K. Scott; Meinhardt, Kerry D.; Stevenson, Jeffry W.; Paxton, Dean M.; Xia, Guanguang; Kim, Dong-Sang

    2003-01-02

    In most planar SOFC stacks operating at an intermediate temperature (700-800 degrees C), the interconnect is typically made from a ferritic stainless steel and has to be hermitically sealed to its adjacent components, such as the ceramic PEN (Positive electrode-Electrolyte-Negative electrode) by a sealing glass. To large extent the seal performance relies on the chemical compatibility of the sealing glass with the metallic interconnect. In this study, a barium-calcium-aluminosilicate (BCAS) based glass-ceramic, specifically developed as a sealant in SOFC stacks, and a ferritic stainless steel (446) were chosen as examples to investigate the chemical interactions or corrosions at the sealing glass interface with the ferritic stainless steels. Evaluation of the interfaces of coupon joints indicated that interactions between the BCAS glass-ceramic and the ferritic stainless steel depended on the exposure conditions. At the edges of joints, where oxygen or air was accessible, the interaction often led to the formation of BaCrO4, while in the interior of the joints, chromium or chromia dissolved into the glass to form a thin layer of chromium rich solid solution. It was also found that, in the interior of the joints, the interaction often resulted in the formation of pores aligning along the interface. The pore formation along the interface of sealing glass and ferritic stainless steel however could be avoided through a pre-heat treatment of the ferriitc stainless steel.

  18. Relationships among the structural topology, bond strength, and mechanical properties of single-walled aluminosilicate nanotubes.

    PubMed

    Liou, Kai-Hsin; Tsou, Nien-Ti; Kang, Dun-Yen

    2015-10-21

    Carbon nanotubes (CNTs) are regarded as small but strong due to their nanoscale microstructure and high mechanical strength (Young's modulus exceeds 1000 GPa). A longstanding question has been whether there exist other nanotube materials with mechanical properties as good as those of CNTs. In this study, we investigated the mechanical properties of single-walled aluminosilicate nanotubes (AlSiNTs) using a multiscale computational method and then conducted a comparison with single-walled carbon nanotubes (SWCNTs). By comparing the potential energy estimated from molecular and macroscopic material mechanics, we were able to model the chemical bonds as beam elements for the nanoscale continuum modeling. This method allowed for simulated mechanical tests (tensile, bending, and torsion) with minimum computational resources for deducing their Young's modulus and shear modulus. The proposed approach also enabled the creation of hypothetical nanotubes to elucidate the relative contributions of bond strength and nanotube structural topology to overall nanotube mechanical strength. Our results indicated that it is the structural topology rather than bond strength that dominates the mechanical properties of the nanotubes. Finally, we investigated the relationship between the structural topology and the mechanical properties by analyzing the von Mises stress distribution in the nanotubes. The proposed methodology proved effective in rationalizing differences in the mechanical properties of AlSiNTs and SWCNTs. Furthermore, this approach could be applied to the exploration of new high-strength nanotube materials.

  19. Thermodynamics of aluminosilicate garnet solid solution: new experimental data, an optimized model, and thermometric applications

    NASA Astrophysics Data System (ADS)

    Ganguly, J.; Cheng, Weiji; Tirone, Massimiliano

    1996-12-01

    We have experimentally determined the displacement of the equilibrium Grossular + 2 Kyanite + Quartz ⇆ 3 Anorthite (GASP) as a function of garnet composition in the systems Mg-Ca-Mn, Fe-Mg-Ca and Fe-Mg-Ca-Mn at 1000°C. The results were treated along with selected experimental and observational data available in the literature as well as binary parameters from other workers to obtain a set of mutually compatible binary mixing parameters of the quaternary (Fe,Mg,Ca,Mn)- aluminosilicate garnet solid solution. Attempts to determine equilibrium garnet composition in the GASP equilibrium in the Ca-Mg binary were unsuccessful due to the formation of pyroxene. Calculations of binary and ternary miscibility gaps show that the P,T,X combination required for unmixing of garnet solid solution is not realized by natural samples. The solution model was applied to account for compositional effects on Fe-Mg exchange between garnet and ortho- or clino-pyroxene. Applications of the revised thermometric formulations to selected natural assemblages yield P-T conditions which are much less sensitive to compositional effects compared to the other available formulations, and are consistent with independent constraints.

  20. Synthesis, characterization, and mercury adsorption properties of hybrid mesoporous aluminosilicate sieve prepared with fly ash

    PubMed Central

    Liu, Minmin; Hou, Li-an; Xi, Beidou; Zhao, Ying; Xia, Xunfeng

    2013-01-01

    A novel hybrid mesoporous aluminosilicate sieve (HMAS) was prepared with fly ash and impregnated with zeolite A precursors. This improved the mercury adsorption of HMAS compared to original MCM-41. The HMAS was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption, Fourier transform infrared (FTIR) analysis, transmission electron microscopy (TEM) images and 29Si and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectra. These showed that the HMAS structure was still retained after impregnated with zeolite A. But the surface area and pore diameter of HMAS decreased due to pore blockage. Adsorption of mercury from aqueous solution was studied on untreated MCM-41and HMAS. The mercury adsorption rate of HMAS was higher than that of origin MCM-41. The adsorption of mercury was investigated on HMAS regarding the pH of mercury solution, initial mercury concentration, and the reaction temperature. The experimental data fit well to Langmuir and Freundlich isotherm models. The Dublin–Radushkevich isotherm and the characterization show that the mercury adsorption on HMAS involved the ion-exchange mechanisms. In addition, the thermodynamic parameters suggest that the adsorption process was endothermic in nature. The adsorption of mercury on HMAS followed the first order kinetics. PMID:23687400

  1. Calcium-Magnesium-Aluminosilicate (CMAS) Reactions and Degradation Mechanisms of Advanced Environmental Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Ahlborg, Nadia L.; Zhu, Dongming

    2013-01-01

    The thermochemical reactions between calcium-magnesium-aluminosilicate- (CMAS-) based road sand and several advanced turbine engine environmental barrier coating (EBC) materials were studied. The phase stability, reaction kinetics and degradation mechanisms of rare earth (RE)-silicates Yb2SiO5, Y2Si2O7, and RE-oxide doped HfO2 and ZrO2 under the CMAS infiltration condition at 1500 C were investigated, and the microstructure and phase characteristics of CMAS-EBC specimens were examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Experimental results showed that the CMAS dissolved RE-silicates to form crystalline, highly non-stoichiometric apatite phases, and in particular attacking the silicate grain boundaries. Cross-section images show that the CMAS reacted with specimens and deeply penetrated into the EBC grain boundaries and formed extensive low-melting eutectic phases, causing grain boundary recession with increasing testing time in the silicate materials. The preliminary results also showed that CMAS reactions also formed low melting grain boundary phases in the higher concentration RE-oxide doped HfO2 systems. The effect of the test temperature on CMAS reactions of the EBC materials will also be discussed. The faster diffusion exhibited by apatite and RE-doped oxide phases and the formation of extensive grain boundary low-melting phases may limit the CMAS resistance of some of the environmental barrier coatings at high temperatures.

  2. Poorly Crystalline, Iron-Bearing Aluminosilicates and Their Importance on Mars

    NASA Technical Reports Server (NTRS)

    Baker, L. L.; Strawn, D. G.; McDaniel, P. A.; Nickerosn, R. N.; Bishop, J. L.; Ming, D. W.; Morris, Richard V.

    2011-01-01

    Martian rocks and sediments contain weathering products including evaporite salts and clay minerals that only form as a result of interaction between rocks and water [1-6]. These weathering products are key to studying the history of water on Mars because their type, abundance and location provide clues to past conditions on the surface of the planet, as well as to the possible location of present-day reservoirs of water. Weathering of terrestrial volcanic rocks similar to those on Mars produces nano-sized, variably hydrated aluminosilicate and iron oxide minerals [7-10] including allophane, imogolite, halloysite, hisingerite, and ferrihydrite. The nanoaluminosilicates can contain isomorphically substituted Fe, which affects their spectral and physical properties. Detection and quantification of such minerals in natural environments on earth is difficult due to their variable chemical composition and lack of long-range crystalline order [9, 11, 12]. Despite the difficulty in characterizing these materials, they are common on Earth, and data from orbital remote sensing and rover-based instruments suggest that they are also present on Mars [9, 10, 13-17]. Their accurate detection and quantification require a better understanding of how composition affects their spectral properties. We present here the results of XAFS spectroscopy; these results will be corroborated with planned Mossbauer and reflectance spectroscopy.

  3. Fabrication of large diameter alumino-silicate K{sup +} sources

    SciTech Connect

    Baca, D.; Chacon-Golcher, E.; Kwan, J.W.; Wu, J.K.

    2003-02-20

    Alumino-silicate K{sup +} sources have been used in HIF experiments for many years. For example the Neutralized Transport Expt. (NTX) and the High Current Transport Expt. (HCX) are now using this type of ion source with diameters of 2.54 cm and 10 cm respectively. These sources have demonstrated ion currents of 80 mA and 700 mA, for typical HIF pulse lengths of 5-10 {micro}s. The corresponding current density is {approx} 10-15 mA/cm{sup 2}, but much higher current density has been observed using smaller size sources. Recently we have improved our fabrication techniques and, therefore, are able to reliably produce large diameter ion sources with high quality emitter surface without defects. This note provides a detailed description of the procedures employed in the fabrication process. The variables in the processing steps affecting surface quality, such as substrate porosity, powder size distribution, coating technique on large area concave surfaces, drying, and heat firing temperature have been investigated.

  4. Synthesis of hydrothermally stable, hierarchically mesoporous aluminosilicate Al-SBA-1 and their catalytic properties

    NASA Astrophysics Data System (ADS)

    Li, Na; Wang, Jin-Gui; Xu, Jian-Xiong; Liu, Jin-Yu; Zhou, Hui-Jing; Sun, Ping-Chuan; Chen, Tie-Hong

    2012-03-01

    Hydrothermally stable mesoporous aluminosilicates Al-SBA-1 with hierarchical pore structure have been successfully synthesized under alkaline condition at 120 °C by employing organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template. The Si/Al ratio could be as high as 5 and the incorporation of Al into the silica framework did not disturb the well-ordered cubic Pm3&cmb.macr;n mesostructure. Meanwhile, the incorporation of Al could greatly increase the specific surface area and pore volume of the samples. The Al-SBA-1 materials exhibited a high hydrothermal stability and remained stable even after being treated in boiling water for 10 days. The catalytic activity of the Al-SBA-1 materials was investigated by employing the Friedel-Crafts alkylation of toluene with benzyl alcohol as a model reaction and they exhibited excellent catalytic property due to the incorporated acid sites and the hierarchically mesoporous structure.

  5. Pressure induced elastic softening in framework aluminosilicate- albite (NaAlSi3O8)

    PubMed Central

    Mookherjee, Mainak; Mainprice, David; Maheshwari, Ketan; Heinonen, Olle; Patel, Dhenu; Hariharan, Anant

    2016-01-01

    Albite (NaAlSi3O8) is an aluminosilicate mineral. Its crystal structure consists of 3-D framework of Al and Si tetrahedral units. We have used Density Functional Theory to investigate the high-pressure behavior of the crystal structure and how it affects the elasticity of albite. Our results indicate elastic softening between 6–8 GPa. This is observed in all the individual elastic stiffness components. Our analysis indicates that the softening is due to the response of the three-dimensional tetrahedral framework, in particular by the pressure dependent changes in the tetrahedral tilts. At pressure <6 GPa, the PAW-GGA can be described by a Birch-Murnaghan equation of state with  = 687.4 Å3,  = 51.7 GPa, and  = 4.7. The shear modulus and its pressure derivative are  = 33.7 GPa, and  = 2.9. At 1 bar, the azimuthal compressional and shear wave anisotropy  = 42.8%, and  = 50.1%. We also investigate the densification of albite to a mixture of jadeite and quartz. The transformation is likely to cause a discontinuity in density, compressional, and shear wave velocity across the crust and mantle. This could partially account for the Mohorovicic discontinuity in thickened continental crustal regions. PMID:27734903

  6. Aluminosilicates and biphasic HA-TCP composites: studies of properties for bony filling.

    PubMed

    Oudadesse, H; Derrien, A C; Mami, M; Martin, S; Cathelineau, G; Yahia, L

    2007-03-01

    Aluminosilicate materials synthesized at room temperature present good mechanical properties. Hydroxyapatite, tricalcium phosphate or both offer a high biocompatibility in the biomedical field. In this work, we focused on the composites resulting from associations of these materials. The best compromise between porosity and biomechanical properties versus different parameters was determined. The in vitro behaviour of compounds in contact with the simulated body fluid (SBF) was studied and in vivo experiments in a rabbit's thighbones were carried out. The inductively coupled plasma-optical emission spectroscopy (ICP-OES) method permitted us to study the eventual release of Al from composites to SBF and to evaluate the chemical stability of composites characterized by the succession of SiO(4) and AlO(4) tetrahedra. The kinetic biomineralization, the bioconsolidation and biological studies were made. The results obtained show the chemical stability of composites. In the bone-implant interface, the intimate links reveal the high quality of the biointegration and the bioconsolidation between composites and bony matrix. Histological studies confirm good bony bonding and highlight the total absence of inflammation or fibrous tissues.

  7. Monodisperse Aluminosilicate Spheres with Tunable Al/Si Ratio and Hierarchical Macro-Meso-Microporous Structure.

    PubMed

    Sheng, Yuan; Zeng, Hua Chun

    2015-06-24

    While tremendous success has been seen in the development of ordered mesoporous silica by soft-templated methods, synthesis of hierarchical structures with controllable multiscale pore networks has remained a challenging topic. On the other hand, introduction of heteroatoms as an effective method of chemically functionalizing silica leads to difficulties in morphological control of the product, and multistep synthesis has been necessary for functionalized silica particles with hierarchical pore structure and uniform size. The present work demonstrates that the conflict between morphological control and heteroatom incorporation can be resolved in a CTAB-stabilized toluene-water-ethanol microemulsion system. For the first time, monodisperse macro-meso-microporous aluminosilicate spheres (MASS) are synthesized in one step at room temperature. Simultaneous tuning of Al/Si ratio (0-0.35) and the hierarchical pore structure is realized by Hofmeister anion effects of the Al source itself, [Al(OH)4](-), which change the geometry of CTAB micelles and giant vesicles. The Al is incorporated purely in a tetrahedrally coordinated status, and preliminary results from catalytic experiments show improved acidity of MASS as a catalyst support.

  8. Aluminosilicates and the ageing brain: implications for the pathogenesis of Alzheimer's disease.

    PubMed

    Edwardson, J A; Klinowski, J; Oakley, A E; Perry, R H; Candy, J M

    1986-01-01

    Senile plaques are a neuropathological feature of the ageing brain and consist of abnormal neuritic and glial processes surrounding an extracellular core of material with fibrillary ultrastructure. Present at low densities in the cerebral cortex of most aged individuals, they occur in large numbers in Alzheimer's disease, the major form of senile dementia. Energy-dispersive X-ray microprobe analysis of isolated cores and plaques in situ from patients with Alzheimer's disease or Down's syndrome and from normal controls has shown co-localization of high concentrations of aluminium (4-19%) and silicon (6-24%) at the centre of the core. The presence of these elements as aluminosilicates has been confirmed using solid-state 27Al nuclear magnetic resonance. These findings provide a link with the other major neuropathological feature of Alzheimer's disease, the neurofibrillary tangle-bearing neurons, where high intracellular levels of Al and Si have also been reported. The focal deposition of these elements may be an early and essential factor in the pathogenesis of Alzheimer-type changes, reflecting an increased exposure to aluminium.

  9. Aluminosilicates enhance the infectivity of cytomegalovirus in urine using centrifugation-enhanced antigen detection technology.

    PubMed

    Lee, S H; Biondo, F X; Teichberg, S; Lipson, S M

    1996-04-01

    Due to the inherent lability of CMV, necessary laboratory identification of this infectious agent is often compromised by a delay in specimen transport. Previous studies have addressed the phenomenon of infectivity enhancement/reduction in the rate of infectivity loss by the incorporation into various viral assay systems of trace concentrations of the adsorbents montmorillonite (bentonite [M]) or kaolinite (kaolin [K]). We extended these studies to the clinical setting to identify whether such aluminosilicates would effect an enhanced level of CMV infectivity. The shell vial assay-indirect immunofluorescent assay (SVA-IFA) was utilized in comparative testing throughout this study. The addition of trace concentrations of M or K to the SVA-IFA was found to enhance the infectivity of CMV in urine by 115 and 126%, respectively. The total CMV detection rate by SVA-IFA was 29% (30/105). Three of the 30 (10%) CMV positive specimens were detected only in shell vials which had been supplemented with K or M. Two specimens were isolation positive alone. The addition of K or M to shell vials immediately prior to the start of the SVA-IFA has the potential of (a), enhancing assay readability by increasing the number of fluorescent focus units per vial monolayer and (b), of detecting positive urine specimens with low viral titers which might otherwise not be identified using the conventional SVA-IFA procedure.

  10. Effect of low frequency ultrasound on the surface properties of natural aluminosilicates.

    PubMed

    Novikova, Liudmila; Ayrault, Philippe; Fontaine, Claude; Chatel, Gregory; Jérôme, François; Belchinskaya, Larisa

    2016-07-01

    Structural and surface properties of different natural aluminosilicates (layered, chain and framework structural types) exposed of 20 kHz ultrasound irradiation (0-120 min) in aqueous and 35 wt%. aqueous H2O2 dispersions were studied by X-ray diffraction (XRD), dynamic light scattering (DLS), nitrogen adsorption-desorption, thermal analysis, and Fourier transform infrared spectroscopy (FTIR) techniques. It was confirmed that sonication caused slight changes in the structure of investigated minerals whereas their textural properties were significantly affected. The aqueous dispersions of montmorillonite (Mt), clinoptilolite (Zlt), glauconite (Glt) and palygorskite (Pal) were represented by several particles size fractions according to DLS-study. Ultrasound irradiation produced a decrease of the average particle diameter by 4-6 times in water and by 1.3-5 times in H2O2 dispersions except for Pal, which underwent strong agglomeration. A significant increase of total pore volume and pore diameter was observed for Glt sonicated in H2O2 dispersions whereas for Pal mainly micropore volume sharply increased in both aqueous and H2O2 dispersions.

  11. Microstructure-property relationships of SiC fiber-reinforced magnesium aluminosilicates. 1: Microstructural characterization

    SciTech Connect

    Kumar, A.; Knowles, K.M.

    1996-07-01

    The microstructure of two magnesium aluminosilicates unidirectionally reinforced with SiC fibers (Nicalon) has been examined. A diphasic interlayer having a higher O/Si ratio than in the fibers was found on the surface of the fibers in both composites. This interlayer could be identified as an amorphous mixture of silica and carbon in the composite hot-pressed just below the liquidus temperature of stoichiometric cordierite (composite A). In the other composite hot-pressed at 920 C and subsequently ceramed at 1,150 C (composite B), a relatively thicker diphasic interlayer was observed, consisting of turbostratic carbon together with amorphous silica. A distinct interlayer of turbostratic carbon was identified in composite A. A thin interlayer consisting mostly of matrix elements was also identified between the diphasic interlayer and the discrete carbon interlayer in this composite. Differences in the structure and morphology of interfacial regions in the two composites could clearly be attributed to differences in the hot-pressing schedules. The basal planes of turbostratic carbon were aligned parallel to the fiber-matrix interfaces in both composites.

  12. A silica optical fiber doped with yttrium aluminosilicate nanoparticles for supercontinuum generation

    NASA Astrophysics Data System (ADS)

    Cheng, Tonglei; Liao, Meisong; Xue, Xiaojie; Li, Jiang; Gao, Weiqing; Li, Xia; Chen, Danping; Zheng, Shupei; Pan, Yubai; Suzuki, Takenobu; Ohishi, Yasutake

    2016-03-01

    We design and fabricate a silica optical fiber doped with yttrium aluminosilicate (YAS, Y2O3-Al2O3-SiO2) nanoparticles in the core. The optical fiber is drawn directly from a silica tube with YAG (Y3Al5O12) ceramics and silica powders (the molar ratio 1:18) in the core at the temperature of ∼1950 °C. The YAS nanoparticles are formed during the optical fiber drawing process. Supercontinuum (SC) generation in the optical fiber is investigated at different pump wavelength. At the pump wavelength of ∼1750 nm which is in the deep anomalous dispersion region, SC spectrum evolution is mainly due to multiple solitons and dispersive waves (DWs), and three pairs of multiple optical solitons and DWs are observed. When the pump wavelength shifts to ∼1500 nm which is close to the zero-dispersion wavelength (ZDW), flattened SC spectrum with ±7 dB uniformity is obtained at the wavelength region of ∼990-1980 nm, and only one obvious soliton and DW are observed. At the pump wavelength of ∼1100 nm, a narrow SC spectrum from ∼1020 to 1180 nm is obtained in the normal dispersion region due to self-phase modulation (SPM) effect.

  13. Preparation of bioinorganic fertilizing media by adsorption of humates on glassy aluminosilicates.

    PubMed

    Chassapis, Konstantinos; Roulia, Maria; Vrettou, Evangelia; Parassiris, Anastassios

    2010-11-01

    Surface-modified expanded perlite was synthesized using humic substances from the Megalopolis peaty lignite. Adsorption is efficient and increases at higher temperatures and lower pHs. The preparation can be carried out under mild conditions leading to an eco-friendly, bioinorganic material useful as soil conditioner and biofertilizer. Six adsorption models were applied; the Klotz, Freundlich and Redlich-Peterson isotherms fit more successfully to the experimental data. The obeying of the theoretical models was correlated with the heterogeneity and non-uniform distribution of the adsorption sites, host-guest attraction forces as well as the formation of self-assembled aggregates and self-organized multilayers of humic substances onto the aluminosilicate adsorbent, consistent with changes in micromorphology. Thermodynamic quantities revealing distinct physicochemical characteristics of the adsorption phenomena, i.e., enthalpy, entropy and free energy change, were calculated. Desorption experiments and cultivation of microorganisms demonstrated that perlite may act successfully as host material for microbial populations upgrading the humic-loaded perlite for soil applications.

  14. Surface of a calcium aluminosilicate glass by classical and ab initio molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Ganster, Patrick; Benoit, Magali; Delaye, Jean-Marc; Kob, Walter

    We present the structural properties of thin films of a calcium aluminosilicate glass generated by classical molecular dynamics (MD). The films are generated by two methods: in the first, the films are created in the liquid state and quenched to 300 K; in the second, the films are generated at room temperature. Depending on the method, film thickness and surface roughness are different but the main structural characteristics of the films are similar. The atomic concentration appears to be inhomogeneous from the center of the films to the surface and new structural entities are present at the film surfaces. The surfaces are depleted in calcium atoms and are enriched in aluminum atoms. This atomic arrangement induces a de-polymerized area under the surface. At the surface, all structural properties are modified in comparison with those of the bulk: interatomic distances, angular distributions, ring size, coordinations. In order to confirm the surface properties, we relaxed a surface using ab initio molecular dynamics. Some modifications appear but they do not significantly change the results obtained by classical MD, validating the use of interatomic potentials for the study of such films.

  15. Microstructure and Cs Behavior of Ba-Doped Aluminosilicate Pollucite Irradiated with F+ Ions

    SciTech Connect

    Jiang, Weilin; Kovarik, Libor; Zhu, Zihua; Varga, Tamas; Engelhard, Mark H.; Bowden, Mark E.; Nenoff, Tina M.; Garino, Terry

    2014-06-24

    Radionuclide 137Cs is one of the major fission products that dominate heat generation in spent fuels over the first 300 hundred years. A durable waste form for 137Cs that decays to 137Ba is needed to minimize its environmental impact. Aluminosilicate pollucite CsAlSi2O6 is selected as a model waste form to study the decay-induced structural effects. While Ba-containing precipitates are not present in charge-balanced Cs0.9Ba0.05AlSi2O6, they are found in Cs0.9Ba0.1AlSi2O6 and identified as monoclinic Ba2Si3O8. Pollucite is susceptible to electron irradiation induced amorphization. The threshold density of the electronic energy deposition for amorphization is determined to be ~235 keV/nm3. Pollucite can be readily amorphized under F+ ion irradiation at 673 K. A significant amount of Cs diffusion and release from the amorphized pollucite is observed during the irradiation. However, cesium is immobile in the crystalline structure under He+ ion irradiation at room temperature. The critical temperature for amorphization is not higher than 873 K under F+ ion irradiation. If kept at or above 873 K all the time, the pollucite structure is unlikely to be amorphized; Cs diffusion and release are improbable. A general discussion regarding pollucite as a potential waste form is provided in this report.

  16. Molecular Dynamics Simulations of Uranyl and Uranyl Carbonate Adsorption at Alumino-silicate Surfaces

    SciTech Connect

    Kerisit, Sebastien N.; Liu, Chongxuan

    2014-03-03

    Adsorption at mineral surfaces is a critical factor controlling the mobility of uranium(VI) in aqueous environments. Therefore, molecular dynamics (MD) simulations were performed to investigate uranyl(VI) adsorption onto two neutral alumino-silicate surfaces, namely the orthoclase (001) surface and the octahedral aluminum sheet of the kaolinite (001) surface. Although uranyl preferentially adsorbed as a bi-dentate innersphere complex on both surfaces, the free energy of adsorption at the orthoclase surface (-15 kcal mol-1) was significantly more favorable than that at the kaolinite surface (-3 kcal mol-1), which was attributed to differences in surface functional groups and to the ability of the orthoclase surface to dissolve a surface potassium ion upon uranyl adsorption. The structures of the adsorbed complexes compared favorably with X-ray absorption spectroscopy results. Simulations of the adsorption of uranyl complexes with up to three carbonate ligands revealed that uranyl complexes coordinated to up to 2 carbonate ions are stable on the orthoclase surface whereas uranyl carbonate surface complexes are unfavored at the kaolinite surface. Combining the MD-derived equilibrium adsorption constants for orthoclase with aqueous equilibrium constants for uranyl carbonate species indicates the presence of adsorbed uranium complexes with one or two carbonates in alkaline conditions, in support of current uranium(VI) surface complexation models.

  17. Chemical and mechanical consequences of environmental barrier coating exposure to calcium-magnesium-aluminosilicate.

    SciTech Connect

    Harder, B.; Ramirez-Rico, J.; Almer, J. D.; Kang, L.; Faber, K.

    2011-06-01

    The success of Si-based ceramics as high-temperature structural materials for gas turbine applications relies on the use of environmental barrier coatings (EBCs) with low silica activity, such as Ba{sub 1-x}Sr{sub x}Al{sub 2}Si{sub 2}O{sub 8} (BSAS), which protect the underlying components from oxidation and corrosion in combustion environments containing water vapor. One of the current challenges concerning EBC lifetime is the effect of sandy deposits of calcium-magnesium-aluminosilicate (CMAS) glass that melt during engine operation and react with the EBC, changing both its composition and stress state. In this work, we study the effect of CMAS exposure at 1300 C on the residual stress state and composition in BSAS-mullite-Si-SiC multilayers. Residual stresses were measured in BSAS multilayers exposed to CMAS for different times using high-energy X-ray diffraction. Their microstructure was studied using a combination of scanning electron microscopy and transmission electron microscopy techniques. Our results show that CMAS dissolves the BSAS topcoat preferentially through the grain boundaries, dislodging the grains and changing the residual stress state in the topcoat to a nonuniform and increasingly compressive stress state with increasing exposure time. The presence of CMAS accelerates the hexacelsian-to-celsian phase transformation kinetics in BSAS, which reacts with the glass by a solution-reprecipitation mechanism. Precipitates have crystallographic structures consistent with Ca-doped celsian and Ba-doped anorthite.

  18. First Principles Studies of Fe-Containing Aluminosilicate and Aluminogermanate Nanotubes.

    PubMed

    Alvarez-Ramírez, Fernando

    2009-12-01

    A theoretical study of the electronic effects of the inclusion of iron on aluminosilicates and aluminogermanates nanotubes with imogolite-like structure was carried out by unrestricted all-electron density functional theory calculations of periodic boundary models. The iron ion was incorporated to the imogolitic models by an isomorphic substitution of Al by Fe and by the adsorption of the Fe ion in the inner and outer nanotube structure in the octahedral hydrated configuration. Additionally, the effects of the Fe concentration in the interval 0.05 ≤ x ≤ 0.1 were analyzed. We observe a drastic reduction of the bandgap value from 4.6 to 2.6 eV and from 4.2 to 1.0 eV for the silicon and germanium respectively. Finally, in all the models there is a shift of the Fermi energy toward the gap region as a result of the inclusion of iron electronic states in the bandgap region.

  19. Possibility of sweet corn synthetic seed production.

    PubMed

    Thobunluepop, P; Pawelzik, E; Vearasilp, S

    2009-08-01

    Somatic embryogenesis in sweet corn has been reported by a number of workers. However, the knowledge maintaining storage life, vigor and viability of these somatic embryos are limited. A model system of synchronous somatic embryos production combined with encapsulation to synthetic seed was studied in sweet corn (Zea mays var. saccharata). In this study immature zygotic embryo cultured on N6 medium, contained 2, 4-D 2 mg L(-1) and sucrose 60 g L(-1) form the embryogenic callus. Higher 2, 4-D levels did not show increasing in inducing embryogenic callus. If the concentration of 2, 4-D decreased globular-stage, somatic zygote form the roots. Somatic embryo develop without surrounding nutritive tissues and protective seed coat has been devoted to causing somatic embryos to functionally mimic embryo, then was encapsulated by 3% (w/v) sodium alginate with 4-6 mm in diameter. It was found that when synthetic seed were treated with 60 g L(-1) sucrose and stored at 15+/-2 degree Celsius for 2 weeks, the survival rate of synthetic seed were 44%, after 8 days of germination test, it was found that there were 91% of which were normal seedling and 9% were abnormal seedling. This result indicated that there is a possibility in sweet corn synthetic seed production. Anyhow, more research for better technique are further required. PMID:19943466

  20. What Are Synthetic Cannabinoids?

    MedlinePlus

    ... those produced by marijuana: elevated mood relaxation altered perception —awareness of surrounding objects and conditions symptoms of ... those produced by marijuana: elevated mood relaxation altered perception symptoms of psychosis Synthetic cannabinoids can also cause ...

  1. Analysis of Synthetic Polymers.

    ERIC Educational Resources Information Center

    Smith, Charles G.; And Others

    1989-01-01

    Reviews techniques for the characterization and analysis of synthetic polymers, copolymers, and blends. Includes techniques for structure determination, separation, and quantitation of additives and residual monomers; determination of molecular weight; and the study of thermal properties including degradation mechanisms. (MVL)

  2. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H.; Thaller, L. H.

    1982-01-01

    The group of techniques that as a class are referred to as synthetic battery cycling are described with reference to spacecraft battery systems. Synthetic battery cycling makes use of the capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system.

  3. Synthetic approaches to monofluoroalkenes.

    PubMed

    Landelle, Grégory; Bergeron, Maxime; Turcotte-Savard, Marc-Olivier; Paquin, Jean-François

    2011-05-01

    Monofluoroalkenes are an important fluorinated class of compounds with applications in medicinal chemistry, material sciences and organic chemistry. An overview of methods allowing synthetic access to these fluorinated building blocks is provided. In particular, this critical review, which covers publications up to October 2010, will be divided according to the substitution pattern of the monofluoroalkenes, i.e. di-, tri- or tetra-substituted. Within each group, the various synthetic approaches will be divided according to the reaction type (282 references).

  4. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  5. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium, and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  6. Synthetic biology and biosecurity.

    PubMed

    Robienski, Jürgen; Simon, Jürgen

    2014-01-01

    This article discusses the conflict fields and legal questions of synthetic biology, esp. concerning biosecurity. A respective jurisprudential discussion has not taken place yet in Germany apart from few statements and recommendations. But in Germany, Europe and the USA, it is generally accepted that a broad discussion is necessary. This is esp. true for the question of biosecurity and the possible dangers arising from Synthetic Biology. PMID:25845204

  7. Synthetic Vision Systems

    NASA Technical Reports Server (NTRS)

    Prinzel, L.J.; Kramer, L.J.

    2009-01-01

    A synthetic vision system is an aircraft cockpit display technology that presents the visual environment external to the aircraft using computer-generated imagery in a manner analogous to how it would appear to the pilot if forward visibility were not restricted. The purpose of this chapter is to review the state of synthetic vision systems, and discuss selected human factors issues that should be considered when designing such displays.

  8. Idraparinux sodium: SANORG 34006, SR 34006.

    PubMed

    2004-01-01

    Idraparinux sodium [SANORG 34006, SR 34006], a synthetic, anti Xa pentasaccharide and analogue of SR 32701 and fondaparinux sodium, was in development with Sanofi (now Sanofi-Synthélabo) and Organon (Akzo Nobel) in Europe and the USA (now Sanofi-Synthélabo alone). It may have potential in the treatment and secondary prevention of thrombosis, especially deep-vein thrombosis (DVT). Because of the long duration of action of idraparinux sodium, it may be suitable for once-weekly administration. In January 2004, Sanofi-Synthélabo announced it was to acquire, before the end of the first quarter 2004, all the rights of Organon relating to idraparinux sodium, subject to approval of the regulatory authorities. Sanofi-Synthélabo is to make payments to Organon based on future sales. Idraparinux sodium has completed phase IIb development with the PERSIST study and it is in phase III clinical trials. In June 2003, Organon announced the initiation of pivotal phase III studies as a once-weekly treatment of DVT and pulmonary embolism (PE), and for the prevention of stroke in patients with atrial fibrillation. The AMADEUS study will focus on patients with atrial fibrillation while the Van Gogh PE, Van Gogh DVT and the Van Gogh extension (EXT) will focus on patients with DVT or PE.

  9. Modelling Cometary Sodium Tails

    NASA Astrophysics Data System (ADS)

    Birkett, K. S.; Jones, G. H.; Coates, A. J.

    2013-12-01

    Neutral sodium is readily observed in cometary spectra and can be seen to form its own distinct tail at high activity comets. Solar radiation pressure accelerates the sodium atoms antisunward and, as strong sodium absorption lines are present in the solar spectrum, the magnitude of this force is dependent upon the Doppler shift of the incident solar radiation. Therefore the heliocentric velocity of the sodium atom directly determines its acceleration. This can produce unique effects, such as a stagnation region. Sodium is relatively easy to detect and so can potentially be used to trace mechanisms in the coma that are otherwise difficult to observe. The source of neutral sodium in the tail currently remains unknown. We have therefore developed a new, three dimensional Monte-Carlo model of neutral cometary sodium in order to facilitate testing of different source production functions. It includes weightings due to neutral sodium lifetime, variation of cometary sodium emission due to Fraunhofer absorption lines and solar flux variation with heliocentric distance. The Swings and Greenstein effects, which can have particularly dramatic effects in near-Sun comets, are also considered comprehensively. Preliminary results from this model are presented, focusing on a comparison of predictions of the neutral sodium tail of Comet C/2012 S1 (ISON) with initial observations.

  10. A high-capacity, low-cost layered sodium manganese oxide material as cathode for sodium-ion batteries.

    PubMed

    Guo, Shaohua; Yu, Haijun; Jian, Zelang; Liu, Pan; Zhu, Yanbei; Guo, Xianwei; Chen, Mingwei; Ishida, Masayoshi; Zhou, Haoshen

    2014-08-01

    A layered sodium manganese oxide material (NaMn3 O5 ) is introduced as a novel cathode materials for sodium-ion batteries. Structural characterizations reveal a typical Birnessite structure with lamellar stacking of the synthetic nanosheets. Electrochemical tests reveal a particularly large discharge capacity of 219 mAh g(-1) in the voltage rang of 1.5-4.7 V vs. Na/Na(+) . With an average potential of 2.75 V versus sodium metal, layered NaMn3 O5 exhibits a high energy density of 602 Wh kg(-1) , and also presents good rate capability. Furthermore, the diffusion coefficient of sodium ions in the layered NaMn3 O5 electrode is investigated by using the galvanostatic intermittent titration technique. The results greatly contribute to the development of room-temperature sodium-ion batteries based on earth-abundant elements.

  11. Optimization of diclofenac sodium profile from halloysite nanotubules.

    PubMed

    Krejčová, Kateřina; Deasy, Patrick B; Rabišková, Miloslava

    2013-04-01

    Halloysite, aluminosilicate clay with the particle shape of multilayered hollow nanotubes, used in various non-medical applications, e.g. in ceramic industry, was discovered for pharmaceutical purposes in recent years. Several drugs of hydrophilic and lipophilic nature have been successfully encapsulated into halloysite tubules in order to modify their dissolution profile. The main goal of this experiment was to optimize the dissolution profile of diclofenac sodium - a drug with problematic solubility - from halloysite tubules using various polymers. Loading of the drug together with povidone or Eudragit® RS did not lead to drug burst effect reduction and its slower dissolution. In the case of povidone, drug improved wettability and solubilization rather than viscosity increasing expectations were observed. Eudragit® RS formed a solid dispersion with diclofenac sodium and thus the solvent/drug solution penetration through the polymer and not the drug solubility was the dissolution rate limiting factor. Reduction of the burst effect and further prolongation of drug release was achieved by coating the drug-loaded halloysite with chitosan. This formulation exhibited a diffusion-controlled prolonged release following Higuchi kinetic model.

  12. Sodium remote from Io

    NASA Astrophysics Data System (ADS)

    Brown, R. A.; Schneider, N. M.

    1981-12-01

    Measurements of sodium emission lines originating in the middle Jupiter magnetosphere are measured, confirming the wide dispersal of neutral sodium in the Jovian system in at least two distinct manifestations. Candidate neutral transport processes in the context of the observed kinematical signatures are discussed. It is argued that the normal emission feature is produced by sodium atoms on bound elliptical orbits originating in the Io sodium cloud but with apojove in the field of view. Observations of the fast sodium feature indicate that atoms episodically acquire a broad range of line-of-sight velocities above the Jupiter gravitational escape speed and far above the speeds characteristic of surface-sputtered atoms. Three suggested reactions are distinguished according to (1) production rates based on estimated plasmaspheric properties, (2) kinematical signature, and (3) the timing of occurrences of the fast sodium feature.

  13. Relationships among the structural topology, bond strength, and mechanical properties of single-walled aluminosilicate nanotubes

    NASA Astrophysics Data System (ADS)

    Liou, Kai-Hsin; Tsou, Nien-Ti; Kang, Dun-Yen

    2015-10-01

    Carbon nanotubes (CNTs) are regarded as small but strong due to their nanoscale microstructure and high mechanical strength (Young's modulus exceeds 1000 GPa). A longstanding question has been whether there exist other nanotube materials with mechanical properties as good as those of CNTs. In this study, we investigated the mechanical properties of single-walled aluminosilicate nanotubes (AlSiNTs) using a multiscale computational method and then conducted a comparison with single-walled carbon nanotubes (SWCNTs). By comparing the potential energy estimated from molecular and macroscopic material mechanics, we were able to model the chemical bonds as beam elements for the nanoscale continuum modeling. This method allowed for simulated mechanical tests (tensile, bending, and torsion) with minimum computational resources for deducing their Young's modulus and shear modulus. The proposed approach also enabled the creation of hypothetical nanotubes to elucidate the relative contributions of bond strength and nanotube structural topology to overall nanotube mechanical strength. Our results indicated that it is the structural topology rather than bond strength that dominates the mechanical properties of the nanotubes. Finally, we investigated the relationship between the structural topology and the mechanical properties by analyzing the von Mises stress distribution in the nanotubes. The proposed methodology proved effective in rationalizing differences in the mechanical properties of AlSiNTs and SWCNTs. Furthermore, this approach could be applied to the exploration of new high-strength nanotube materials.Carbon nanotubes (CNTs) are regarded as small but strong due to their nanoscale microstructure and high mechanical strength (Young's modulus exceeds 1000 GPa). A longstanding question has been whether there exist other nanotube materials with mechanical properties as good as those of CNTs. In this study, we investigated the mechanical properties of single

  14. Modeling the Structure of Complex Aluminosilicate Glasses: The Effect of Zinc Addition.

    PubMed

    Bernasconi, Andrea; Dapiaggi, Monica; Pavese, Alessandro; Agostini, Giovanni; Bernasconi, Maurizio; Bowron, Daniel T

    2016-03-10

    An empirical potential structure refinement of neutron and X-ray diffraction data combined with extended absorption fine structure evidence has been applied to the investigation of two distinct sets of complex aluminosilicate glasses containing different quantities of zinc. Data come from (i) neutron and X-ray total scattering experiments, which have been performed at the ISIS neutron spallation source (SANDALS beamline) and at the European Synchrotron Radiation Facility (ID11 beamline), and (ii) EXAFS experiments which have been performed at the European Synchrotron Radiation Facility (BM23 beamline). By careful examination of the modeled ensemble of atoms, a wide range of structural information has been extracted: coordination numbers, bond distances, cluster sizes, type of oxygen sharing, and the preference of large cations to adopt a charge-compensating role. The first series of glasses, which is characterized by a fixed network modifier element content (i.e., Na), shows how the introduction of Zn at the expense of Si and Al network forming elements does not significantly alter the polymerization degree, as a result of its dominant 4-fold coordination. In the case of the second series, which is characterized by fixed network forming element content (i.e., Si and Al), it is shown how the replacement of a network modifier element (i.e., Ca) with the introduction of Zn does not change the propensity of Zn to be mainly 4-fold coordinated by promoting the network. Where appropriate the experimental results have been compared with classical theoretical approaches such as stoichiometric models based on Zachariasen's rules and computational routines. PMID:26848740

  15. Differential Synthetic Aperture Ladar

    SciTech Connect

    Stappaerts, E A; Scharlemann, E

    2005-02-07

    We report a differential synthetic aperture ladar (DSAL) concept that relaxes platform and laser requirements compared to conventional SAL. Line-of-sight translation/vibration constraints are reduced by several orders of magnitude, while laser frequency stability is typically relaxed by an order of magnitude. The technique is most advantageous for shorter laser wavelengths, ultraviolet to mid-infrared. Analytical and modeling results, including the effect of speckle and atmospheric turbulence, are presented. Synthetic aperture ladars are of growing interest, and several theoretical and experimental papers have been published on the subject. Compared to RF synthetic aperture radar (SAR), platform/ladar motion and transmitter bandwidth constraints are especially demanding at optical wavelengths. For mid-IR and shorter wavelengths, deviations from a linear trajectory along the synthetic aperture length have to be submicron, or their magnitude must be measured to that precision for compensation. The laser coherence time has to be the synthetic aperture transit time, or transmitter phase has to be recorded and a correction applied on detection.

  16. Hierarchically structured meso-macroporous aluminosilicates with high tetrahedral aluminium content in acid catalysed esterification of fatty acids.

    PubMed

    Lemaire, Arnaud; Wang, Quan-Yi; Wei, Yingxu; Liu, Zhongmin; Su, Bao-Lian

    2011-11-15

    A simple synthesis pathway has been developed for the design of hierarchically structured spongy or spherical voids assembled meso-macroporous aluminosilicates with high tetrahedral aluminium content on the basis of the aqueous polymerisation of new stabilized alkoxy-bridged single molecular precursors. The intimate mixing of an aluminosilicate ester (sec-BuO)(2)-Al-O-Si(OEt)(3) and a silica co-reactant (tetramethoxysilane, TMOS) with variable ratios and the use of alkaline solutions (pH 13.0 and 13.5) improve significantly the heterocondensation rates between the highly reactive aluminium alkoxide part of the single precursor and added silica co-reactant, leading to aluminosilicate materials with high intra-framework aluminium content and low Si/Al ratios. The spherically-shaped meso-macroporosity was spontaneously generated by the release of high amount of liquid by-products (water/alcohol molecules) produced during the rapid hydrolysis and condensation processes of this double alkoxide and the TMOS co-reactant. It has been observed that both pH value and Al-Si/TMOS molar ratio can strongly affect the macroporous structure formation. Increasing pH value, even slightly from 13 to 13.5, can significantly favour the incorporation of Al atoms in tetrahedral position of the framework. After the total ionic exchange of Na(+) compensating cations, catalytic tests of obtained materials were realised in the esterification reaction of high free fatty acid (FFA) oils, showing their higher catalytic activity compared to commercial Bentonite clay, and their potential applications as catalyst supports in acid catalysed reactions.

  17. Resonant excited state absorption and relaxation mechanisms in Tb3+-doped calcium aluminosilicate glasses: an investigation by thermal mirror spectroscopy.

    PubMed

    Bianchi, G S; Zanuto, V S; Astrath, F B G; Malacarne, L C; Terra, I A A; Catunda, T; Nunes, L A O; Jacinto, C; Andrade, L H C; Lima, S M; Baesso, M L; Astrath, N G C

    2013-11-15

    Resonant excited state absorption (ESA) and relaxation processes in Tb(3+)-doped aluminosilicate glasses are quantitatively evaluated. A model describing the excitation steps and upconversion emission is developed and applied to interpret the results from laser-induced surface deformation using thermal mirror spectroscopy. The fluorescence quantum efficiency of level (5)D(4) was found to be close to unity and concentration independent while, for the level (5)D(3), it decreases with Tb(3+) concentration. Emission spectroscopy measurements supported these results. ESA cross sections are found to be more than three orders of magnitude higher than the ground state absorption cross section. PMID:24322101

  18. Ordered hexagonal mesoporous aluminosilicates synthesized using zeolite as precursor and the wall-thickness tuned by pH control

    NASA Astrophysics Data System (ADS)

    Wang, Chunlei; Zhu, Guangshang; Shang, Tiecun; Cai, Xiaohui; Liu, Chengzhan; Li, Nan; Wei, Yuhong; Li, Jian; Zhang, Weiwei; Qiu, Shilun

    2005-07-01

    High aluminium content mesoporous aluminosilicates MAS-X1 and MAS-X3 have been successfully synthesized using zeolite FAU-X as precursors and triblock copolymer pluronic P123 as structure directing agent. Samples have been characterized by XRD, TEM, nitrogen adsorption/desorption, 27Al MAS NMR, and ICP element analysis techniques. The salt, NaCl, which was introduced by dissolving the zeolite FAU-X, played an important role in the synthesis of high order sample. The secondary growth of the wall was considered to occur after the pH value had been increased up to five.

  19. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; Thaller, L. H.

    1982-01-01

    Synthetic battery cycling makes use of the fast growing capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system. The group of techniques that as a class have been referred to as Synthetic Battery Cycling is developed in part to try to bridge the gap of understanding that exists between single cell characteristics and battery system behavior.

  20. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A.; Page, Ralph H.; Ebbers, Christopher A.; Beach, Raymond J.

    2004-03-09

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  1. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  2. Absorption and luminescence characteristics of 5I7 <--> 5I8 transitions of the holmium ion in Ho3+-doped aluminosilicate preforms and fibres

    NASA Astrophysics Data System (ADS)

    Ryabochkina, P. A.; Chabushkin, A. N.; Kosolapov, A. F.; Kurkov, A. S.

    2015-02-01

    We have obtained the spectral dependences of the absorption cross sections for the Ho3+ 5I8 → 5I6 and 5I8 → 5I7 transitions in Ho3+-doped aluminosilicate fibres and the spectral dependence of the stimulated emission cross section for the Ho3+ 5I7 → 5I8 laser transition in Ho3+-doped aluminosilicate fibre preforms. The lifetime of the Ho3+ 5I7 upper laser level in the preforms has been determined.

  3. Synthetic Visibility System

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Test pilot Lee Person evaluates a Synthetic Visibility System - in essence, two helmet-mounted eyepieces connected to video cameras that swivel in response to head movements. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 113), by James Schultz.

  4. Adaptive synthetic vision

    NASA Astrophysics Data System (ADS)

    Julier, Simon J.; Brown, Dennis; Livingston, Mark A.; Thomas, Justin

    2006-05-01

    Through their ability to safely collect video and imagery from remote and potentially dangerous locations, UAVs have already transformed the battlespace. The effectiveness of this information can be greatly enhanced through synthetic vision. Given knowledge of the extrinsic and intrinsic parameters of the camera, synthetic vision superimposes spatially-registered computer graphics over the video feed from the UAV. This technique can be used to show many types of data such as landmarks, air corridors, and the locations of friendly and enemy forces. However, the effectiveness of a synthetic vision system strongly depends on the accuracy of the registration - if the graphics are poorly aligned with the real world they can be confusing, annoying, and even misleading. In this paper, we describe an adaptive approach to synthetic vision that modifies the way in which information is displayed depending upon the registration error. We describe an integrated software architecture that has two main components. The first component automatically calculates registration error based on information about the uncertainty in the camera parameters. The second component uses this information to modify, aggregate, and label annotations to make their interpretation as clear as possible. We demonstrate the use of this approach on some sample datasets.

  5. Synthetic Aperture Radar Interferometry

    NASA Technical Reports Server (NTRS)

    Rosen, P. A.; Hensley, S.; Joughin, I. R.; Li, F.; Madsen, S. N.; Rodriguez, E.; Goldstein, R. M.

    1998-01-01

    Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

  6. Towards a Synthetic Chloroplast

    PubMed Central

    Agapakis, Christina M.; Niederholtmeyer, Henrike; Noche, Ramil R.; Lieberman, Tami D.; Megason, Sean G.; Way, Jeffrey C.; Silver, Pamela A.

    2011-01-01

    Background The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner. Results We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages. Conclusion Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices. PMID:21533097

  7. Biodegradable synthetic bone composites

    DOEpatents

    Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

    2013-01-01

    The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

  8. Synthetic Bursae for Robots

    NASA Technical Reports Server (NTRS)

    Lovchik, Christopher S.

    2005-01-01

    Synthetic bursae are under development for incorporation into robot joints that are actuated by motor-driven cables in a manner similar to that of arthropod joints actuated by muscle-driven tendons. Like natural bursae, the synthetic bursae would serve as cushions and friction reducers. A natural bursa is a thin bladder filled with synovial fluid, which serves to reduce friction and provide a cushion between a bone and a muscle or a tendon. A synthetic bursa would be similar in form and function: It would be, essentially, a compact, soft roller consisting of a bladder filled with a non-Newtonian fluid. The bladder would be constrained to approximately constant volume. The synthetic bursa would cushion an actuator cable against one of the members of a robot joint and would reduce the friction between the cable and the member. Under load, the pressure in the bladder would hold the opposite walls of the bladder apart, making it possible for them to move freely past each other without rubbing.

  9. Synthetic Confrontation Therapy.

    ERIC Educational Resources Information Center

    Gilliam, Larry

    After initially dispelling predictable fears that his paper might suggest that computers can be equated with man, the author states the problem: what part, if any, might computers play in counseling. Specifically, the possibilities for therapeutic synthetic (artificial) counseling encounters are discussed. Two propositions are significant: (1) the…

  10. Synthetic Vision Workshop 2

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J. (Compiler)

    1999-01-01

    The second NASA sponsored Workshop on Synthetic/Enhanced Vision (S/EV) Display Systems was conducted January 27-29, 1998 at the NASA Langley Research Center. The purpose of this workshop was to provide a forum for interested parties to discuss topics in the Synthetic Vision (SV) element of the NASA Aviation Safety Program and to encourage those interested parties to participate in the development, prototyping, and implementation of S/EV systems that enhance aviation safety. The SV element addresses the potential safety benefits of synthetic/enhanced vision display systems for low-end general aviation aircraft, high-end general aviation aircraft (business jets), and commercial transports. Attendance at this workshop consisted of about 112 persons including representatives from industry, the FAA, and other government organizations (NOAA, NIMA, etc.). The workshop provided opportunities for interested individuals to give presentations on the state of the art in potentially applicable systems, as well as to discuss areas of research that might be considered for inclusion within the Synthetic Vision Element program to contribute to the reduction of the fatal aircraft accident rate. Panel discussions on topical areas such as databases, displays, certification issues, and sensors were conducted, with time allowed for audience participation.

  11. Decode the Sodium Label Lingo

    MedlinePlus

    ... For Preschooler For Gradeschooler For Teen Decode the Sodium Label Lingo Published January 24, 2013 Print Email Reading food labels can help you slash sodium. Here's how to decipher them. "Sodium free" or " ...

  12. Synthetic plant defense elicitors

    PubMed Central

    Bektas, Yasemin; Eulgem, Thomas

    2015-01-01

    To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug-like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection. PMID:25674095

  13. Synthetic River Valleys

    NASA Astrophysics Data System (ADS)

    Brown, R.; Pasternack, G. B.

    2011-12-01

    The description of fluvial form has evolved from anecdotal descriptions to artistic renderings to 2D plots of cross section or longitudinal profiles and more recently 3D digital models. Synthetic river valleys, artificial 3D topographic models of river topography, have a plethora of potential applications in fluvial geomorphology, and the earth sciences in general, as well as in computer science and ecology. Synthetic river channels have existed implicitly since approximately the 1970s and can be simulated from a variety of approaches spanning the artistic and numerical. An objective method of synthesizing 3D stream topography based on reach scale attributes would be valuable for sizing 3D flumes in the physical and numerical realms, as initial input topography for morphodynamic models, stream restoration design, historical reconstruction, and mechanistic testing of interactions of channel geometric elements. Quite simply - simulation of synthetic channel geometry of prescribed conditions can allow systematic evaluation of the dominant relationships between river flow and geometry. A new model, the control curve method, is presented that uses hierarchically scaled parametric curves in over-lapping 2D planes to create synthetic river valleys. The approach is able to simulate 3D stream geometry from paired 2D descriptions and can allow experimental insight into form-process relationships in addition to visualizing past measurements of channel form that are limited to two dimension descriptions. Results are presented that illustrate the models ability to simulate fluvial topography representative of real world rivers as well as how channel geometric elements can be adjusted. The testing of synthetic river valleys would open up a wealth of knowledge as to why some 3D attributes of river channels are more prevalent than others as well as bridging the gap between the 2D descriptions that have dominated fluvial geomorphology the past century and modern, more complete, 3D

  14. The Effect of Micro/Nano-metrics Size on the Interaction of Jordanian Aluminosilicate Raw Materials with High pH Solution

    NASA Astrophysics Data System (ADS)

    Aldabsheh, Islam; Garcia-Valles, Maite; Martinez, Salvador

    2014-05-01

    Environmental preservation has become a driving force behind the search for new sustainable and environmentally friendly composites to replace conventional concrete produced from ordinary Portland cement (OPC). Current researches concentrate on developing building products (geopolymers) through geopolymerization. The goal is to produce low cost construction materials for green housing. Geopolymerization is the process of polymerizing minerals with high silica and alumina at low temperature by the use of alkali solutions. Dissolution is the most important process for supplying the high initial Al and Si concentrations to produce the gel phase that is responsible for geopolymerization. This study has been focused on the influence of different micrometric particle sizes of three Jordanian raw materials on their dissolution behavior in sodium hydroxide solution. The samples are kaolinite, volcanic tuff and silica sand. The dissolution properties of each material, alone and mixed with the other two materials were studied in different concentrations (5 and 10 M) using (NaOH) at 25ºC, and shaking time for 24 and 168 h. To better understand the dissolution process, the alkaline solution was renewed after the desired time in order to know if the Al-Si raw material is completely dissolved or not. Different analytical techniques were used to characterize raw materials physically, mineralogically, chemically and thermally. All processed samples either centrifuged solutions or solid residues were fully characterized. The leached concentrations of Al and Si were determined by inductively coupled plasma (ICP). X-ray Diffraction Technique (XRD), Scanning Electron Microscopy (SEM), and Thermo Gravimetric Analysis (TGA) were used to evaluate the solid residue characterization compared with the original ones. The three aluminosilicate raw materials have indicated variable degrees of solubility under highly alkaline conditions. The method for the size reduction of the used raw

  15. Alumino-silicate speciation in aqueous fluids at deep crustal conditions

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Keppler, H.; Manning, C. E.

    2014-12-01

    Alumina and silica are major oxides in most crustal rocks. While SiO2 is quite soluble in aqueous fluids at metamorphic conditions, behavior of Al2O3 in crustal metamorphic fluids has been poorly understood. It is known that alumina is dramatically less soluble in aqueous fluids and hence it is difficult to explain the common occurrence of quartz with aluminous minerals in metamorphic veins. In order to understand this complex behavior of alumina, we investigated aluminum speciation in aqueous fluids in equilibrium with corundum using in situ Raman spectroscopy in hydrothermal diamond anvil cells to 20 kbar and 1000 oC. In order to better understand the spectral features of the aqueous fluids, we used first principles simulations based on density functional theory to calculate and predict the energetics and vibrational spectra for various aluminum species that are likely to be present in aqueous solutions. The Raman spectra of pure water in equilibrium with Al2O3 are devoid of any characteristic spectral features. In contrast, aqueous fluids with KOH solution in equilibrium with Al2O3 show a sharp band at ~620 cm-1 which could be attributed to the [Al(OH)4]1- species. The band grows in intensity with temperature along an isochore. In the limited pressure, temperature and density explored in the present study, we do not find any evidence for the polymerization of the [Al(OH)4]1- species to dimers [(OH)2-Al-O2-Al(OH)2]2- or [(OH)3-Al-O-Al(OH)3]2-. This is likely due to the relatively low concentration of Al in the solutions and does not rule out significant polymerization at higher pressures and temperatures. We are also investigating the effect of SiO2 on the solubility of Al2O3 and the relative energetics of formation of pure alumina dimer [(OH)3-Al-O-Al(OH)3]2- vs. the aluminosilicate dimers, [(OH)3-Al-O-Si(OH)3]2- at deep crustal conditions. Acknowledgement- MM is supported by the US National Science Foundation grant (EAR-1250477).

  16. Strength enhancement of Nicalon-reinforced lithium aluminosilicate containing a Ta(2)O(5) second phase

    NASA Astrophysics Data System (ADS)

    Villalobos, Guillermo R.

    The purpose of this study was to follow up the preliminary results of a previous thesis which appeared to indicate that the addition of Tasb2Osb5 to the matrix of a Nicalon fiber reinforced lithium aluminosilicate glass ceramic composite increased the mechanical properties of the resulting composites. The strength increase was attributed to the presence of a TaC platelet phase in the matrix material. The TaC was thought to be a result of the reaction between the Tasb2Osb5 additions and soluble CO from the hot press atmosphere used in the densification of the composites. These preliminary results (the strength increase and TaC formation) were a side experiment to a larger work and consequently were not rigorously investigated. The present work showed that the CO did react with Tasb2Osb5 to form TaC, but only as a surface coating. The surface coating reached a terminal thickness of 5-10 mum after 1 h at 1400sp°C. There was no evidence of soluble CO reacting to form TaC in the matrix. What was previously thought to be TaC platelets appears to be a two phase eutectic structure of beta-spodumene and Tasb2Osb5. When the Tasb2Osb5 content was increased to 15%, Tasb2Osb5 crystals were formed in addition to the eutectic structure. The formation of the eutectic structure could be suppressed in samples containing less than 3.5% Tasb2Osb5 by cooling at 10sp°C/min. Cooling rates of 1sp°C/min promoted the two phase structure. The interfacial shear strength and flexural strength did not appreciably increase with Tasb2Osb5 additions. Increasing the hot pressing time did increase the interfacial shear strength, but resulted in lower flexural strengths and less graceful failure modes. There was great variation in the flexural strength of the composites which increased with increasing Tasb2Osb5 content. With the very limited sample size of the preliminary study the large variation may have suggested a trend which did not statistically exist.

  17. Catalytic Fast Pyrolysis of Lignin over High-Surface-Area Mesoporous Aluminosilicates: Effect of Porosity and Acidity.

    PubMed

    Custodis, Victoria B F; Karakoulia, Stamatia A; Triantafyllidis, Kostas S; van Bokhoven, Jeroen A

    2016-05-23

    Catalytic fast pyrolysis (CFP) of lignin with amorphous mesoporous aluminosilicates catalysts yields a high fraction of aromatics and a relatively low amount of char/coke. The relationship between the acidity and porosity of Al-MCM-41, Al-SBA-15, and Al-MSU-J with product selectivity during lignin CFP is determined. The acid sites (mild Brønsted and stronger Lewis) are able to catalyze pyrolysis intermediates towards fewer oxygenated phenols and aromatic hydrocarbons. A generalized correlation of the product selectivity and yield with the aluminum content and acidity of the mesoporous aluminosilicates is hard to establish. Zeolitic strong acid sites are not required to achieve high conversion and selectivity to aromatic hydrocarbon because nanosized MCM-41 produces a high liquid yield and selectivity. The two most essential parameters are diffusion, which is influenced by pore and grain size, and the active site, which may be mildly acidic, but is dominated by Lewis acid sites. Nanosized grains and mild acidity are essential ingredients for a good lignin CFP catalyst. PMID:27079742

  18. Crystalline-like molecularly ordered mesoporous aluminosilicates derived from aluminosilica-surfactant mesophases via benign template removal.

    PubMed

    Xia, Yongde; Mokaya, Robert

    2006-05-11

    We report the preparation of mesoporous aluminosilicate materials that exhibit molecular-scale ordering in their pore wall framework. The materials were derived from mesoporous aluminosilica-surfactant mesophases via benign template removal methods, which allowed the retention of molecular ordering in surfactant-free materials. The molecularly ordered aluminosilica-surfactant mesophases were obtained from hydrothermal crystallization of cetyltrimethylammonium hydroxide/Al,Si/H2O systems at 135 degrees C for 12 days. Benign template removal via H2O2-mediated oxidation of the surfactant at room temperature was found to be the most effective method in generating surfactant-free materials with molecular ordering, high textural properties (depending on Al content), and high acidity. The Al in the resulting aluminosilicates was entirely incorporated in framework (tetrahedrally coordinated) sites. Template extraction in acidified ethanol also generated molecularly ordered materials but compromised the Al content and acidity. Template removal via conventional calcination generated porous materials with high textural properties but which exhibited only limited molecular ordering and had relatively low acidity and significant amounts of nonframework Al. This work demonstrates that molecular ordering in mesoporous silicate-surfactant mesophases is due to crystallographic ordering within inorganic frameworks rather than the arrangement/packing of surfactant molecules.

  19. Catalytic Fast Pyrolysis of Lignin over High-Surface-Area Mesoporous Aluminosilicates: Effect of Porosity and Acidity.

    PubMed

    Custodis, Victoria B F; Karakoulia, Stamatia A; Triantafyllidis, Kostas S; van Bokhoven, Jeroen A

    2016-05-23

    Catalytic fast pyrolysis (CFP) of lignin with amorphous mesoporous aluminosilicates catalysts yields a high fraction of aromatics and a relatively low amount of char/coke. The relationship between the acidity and porosity of Al-MCM-41, Al-SBA-15, and Al-MSU-J with product selectivity during lignin CFP is determined. The acid sites (mild Brønsted and stronger Lewis) are able to catalyze pyrolysis intermediates towards fewer oxygenated phenols and aromatic hydrocarbons. A generalized correlation of the product selectivity and yield with the aluminum content and acidity of the mesoporous aluminosilicates is hard to establish. Zeolitic strong acid sites are not required to achieve high conversion and selectivity to aromatic hydrocarbon because nanosized MCM-41 produces a high liquid yield and selectivity. The two most essential parameters are diffusion, which is influenced by pore and grain size, and the active site, which may be mildly acidic, but is dominated by Lewis acid sites. Nanosized grains and mild acidity are essential ingredients for a good lignin CFP catalyst.

  20. Mercury's sodium exosphere

    NASA Astrophysics Data System (ADS)

    Leblanc, F.; Johnson, R. E.

    2003-08-01

    Mercury's neutral sodium exosphere is simulated using a comprehensive 3D Monte Carlo model following sodium atoms ejected from Mercury's surface by thermal desorption, photon stimulated desorption, micro-meteoroid vaporization and solar wind sputtering. The evolution of the sodium surface density with respect to Mercury's rotation and its motion around the Sun is taken into account by considering enrichment processes due to surface trapping of neutrals and ions and depletion of the sodium available for ejection from the surfaces of grains. The change in the sodium exosphere is calculated during one Mercury year taking into account the variations in the solar radiation pressure, the photo-ionization frequency, the solar wind density, the photon and meteoroid flux intensities, and the surface temperature. Line-of-sight column densities at different phase angles, the supply rate of new sodium, average neutral and ion losses over a Mercury year, surface density distribution and the importance of the different processes of ejection are discussed in this paper. The sodium surface density distribution is found to become significantly nonuniform from day to night sides, from low to high latitudes and from morning to afternoon because of rapid depletion of sodium atoms in the surfaces of grains mainly driven by thermal depletion. The shape of the exosphere, as it would be seen from the Earth, changes drastically with respect to Mercury's heliocentric position. High latitude column density maxima are related to maxima in the sodium surface concentration at high latitudes in Mercury's surface and are not necessarily due to solar wind sputtering. The ratio between the sodium column density on the morning side of Mercury's exosphere and the sodium column density on the afternoon side is consistent with the conclusions of Sprague et al. (1997, Icarus 129, 506-527). The model, which has no fitting parameters, shows surprisingly good agreement with recent observations of Potter et

  1. METHOD FOR REMOVING SODIUM OXIDE FROM LIQUID SODIUM

    DOEpatents

    Bruggeman, W.H.; Voorhees, B.G.

    1957-12-01

    A method is described for removing sodium oxide from a fluent stream of liquid sodium by coldtrapping the sodium oxide. Apparatus utilizing this method is disclosed in United States Patent No. 2,745,552. Sodium will remain in a molten state at temperatures below that at which sodium oxide will crystallize out and form solid deposits, therefore, the contaminated stream of sodium is cooled to a temperature at which the solubility of sodium oxide in sodium is substantially decreased. Thereafter the stream of sodium is passed through a bed of stainless steel wool maintained at a temperature below that of the stream. The stream is kept in contact with the wool until the sodium oxide is removed by crystal growth on the wool, then the stream is reheated and returned to the system. This method is useful in purifying reactor coolants where the sodium oxide would otherwise deposit out on the walls and eventually plug the coolant tubes.

  2. SODIUM DEUTERIUM REACTOR

    DOEpatents

    Oppenheimer, E.D.; Weisberg, R.A.

    1963-02-26

    This patent relates to a barrier system for a sodium heavy water reactor capable of insuring absolute separation of the metal and water. Relatively cold D/sub 2/O moderator and reflector is contained in a calandria into which is immersed the fuel containing tubes. The fuel elements are cooled by the sodium which flows within the tubes and surrounds the fuel elements. The fuel containing tubes are surrounded by concentric barrier tubes forming annular spaces through which pass inert gases at substantially atmospheric pressure. Header rooms above and below the calandria are provided for supplying and withdrawing the sodium and inert gases in the calandria region. (AEC)

  3. Submersible sodium pump

    DOEpatents

    Brynsvold, G.V.; Lopez, J.T.; Olich, E.E.; West, C.W.

    1989-11-21

    An electromagnetic submerged pump has an outer cylindrical stator with an inner cylindrical conductive core for the submerged pumping of sodium in the cylindrical interstitial volume defined between the stator and core. The cylindrical interstitial volume is typically vertically oriented, and defines an inlet at the bottom and an outlet at the top. The outer stator generates upwardly conveyed toroidal magnetic fields, which fields convey preferably from the bottom of the pump to the top of the pump liquid sodium in the cold leg of a sodium cooled nuclear reactor. The outer cylindrical stator has a vertically disposed duct surrounded by alternately stacked layers of coil units and laminates. 14 figs.

  4. Submersible sodium pump

    DOEpatents

    Brynsvold, Glen V.; Lopez, John T.; Olich, Eugene E.; West, Calvin W.

    1989-01-01

    An electromagnetic submerged pump has an outer cylindrical stator with an inner cylindrical conductive core for the submerged pumping of sodium in the cylindrical interstitial volume defined between the stator and core. The cylindrical interstitial volume is typically vertically oriented, and defines an inlet at the bottom and an outlet at the top. The outer stator generates upwardly conveyed toroidal magnetic fields, which fields convey preferably from the bottom of the pump to the top of the pump liquid sodium in the cold leg of a sodium cooled nuclear reactor. The outer cylindrical stator has a vertically disposed duct surrounded by alternately stacked layers of coil units and laminates.

  5. Reduction of nitrogen oxides with catalytic acid resistant aluminosilicate molecular sieves and ammonia

    DOEpatents

    Pence, Dallas T.; Thomas, Thomas R.

    1980-01-01

    Noxious nitrogen oxides in a waste gas stream such as the stack gas from a fossil-fuel-fired power generation plant or other industrial plant off-gas stream is catalytically reduced to elemental nitrogen and/or innocuous nitrogen oxides employing ammonia as reductant in the presence of a zeolite catalyst in the hydrogen or sodium form having pore openings of about 3 to 10 A.

  6. Nanoparticles as synthetic vaccines.

    PubMed

    Smith, Josiah D; Morton, Logan D; Ulery, Bret D

    2015-08-01

    As vaccines have transitioned from the use of whole pathogens to only the required antigenic epitopes, unwanted side effects have been decreased, but corresponding immune responses have been greatly diminished. To enhance immunogenicity, a variety of controlled release vehicles have been proposed as synthetic vaccines, but nanoparticles have emerged as particularly impressive systems due to many exciting publications. In specific, nanoparticles have been shown capable of not only desirable vaccine release, but can also be targeted to immune cells of interest, loaded with immunostimulatory substances termed adjuvants, or even induce desirable immune activating effects on their own. In the present review, recent advances in the utilization of inorganic, polymeric, and biomolecular nanoparticles as synthetic vaccines are discussed.

  7. Synthetic Foveal Imaging Technology

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor); Hoenk, Michael E. (Inventor); Nikzad, Shouleh (Inventor)

    2013-01-01

    Apparatuses and methods are disclosed that create a synthetic fovea in order to identify and highlight interesting portions of an image for further processing and rapid response. Synthetic foveal imaging implements a parallel processing architecture that uses reprogrammable logic to implement embedded, distributed, real-time foveal image processing from different sensor types while simultaneously allowing for lossless storage and retrieval of raw image data. Real-time, distributed, adaptive processing of multi-tap image sensors with coordinated processing hardware used for each output tap is enabled. In mosaic focal planes, a parallel-processing network can be implemented that treats the mosaic focal plane as a single ensemble rather than a set of isolated sensors. Various applications are enabled for imaging and robotic vision where processing and responding to enormous amounts of data quickly and efficiently is important.

  8. Wholly Synthetic Molecular Machines.

    PubMed

    Cheng, Chuyang; Stoddart, J Fraser

    2016-06-17

    The past quarter of a century has witnessed an increasing engagement on the part of physicists and chemists in the design and synthesis of molecular machines de novo. This minireview traces the development of artificial molecular machines from their prototypes in the form of shuttles and switches to their emergence as motors and pumps where supplies of energy in the form of chemical fuel, electrochemical potential and light activation become a minimum requirement for them to function away from equilibrium. The challenge facing this rapidly growing community of scientists and engineers today is one of putting wholly synthetic molecules to work, both individually and as collections. Here, we highlight some of the recent conceptual and practical advances relating to the operation of wholly synthetic rotary and linear motors.

  9. Engineered Asymmetric Synthetic Vesicles

    NASA Astrophysics Data System (ADS)

    Lu, Li; Chiarot, Paul

    2013-11-01

    Synthetic vesicles are small, fluid-filled spheres that are enclosed by a bilayer of lipid molecules. They can be used as models for investigating membrane biology and as delivery vehicles for pharmaceuticals. In practice, it is difficult to simultaneously control membrane asymmetry, unilamellarity, vesicle size, vesicle-to-vesicle uniformity, and luminal content. Membrane asymmetry, where each leaflet of the bilayer is composed of different lipids, is of particular importance as it is a feature of most natural membranes. In this study, we leverage microfluidic technology to build asymmetric vesicles at high-throughput. We use the precise flow control offered by microfluidic devices to make highly uniform emulsions, with controlled internal content, that serve as templates to build the synthetic vesicles. Flow focusing, dielectrophoretic steering, and interfacial lipid self-assembly are critical procedures performed on-chip to produce the vesicles. Fluorescent and confocal microscopy are used to evaluate the vesicle characteristics.

  10. EXPEDITIOUS SYNTHETIC TRANSFORMATIONS USING MICROWAVES

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes will be described for the synthesis of a variety of industrially significant compounds and intermediates namely, enamines, nitroalkenes, enones, oxidized sulfur compounds and ionic liquids. This solvent-free synthetic methodolo...

  11. Chemical synthetic biology.

    PubMed

    Chiarabelli, Cristiano; Luisi, Pier Luigi

    2014-01-01

    Although both the most popular form of synthetic biology (SB) and chemical synthetic biology (CSB) share the biotechnologically useful aim of making new forms of life, SB does so by using genetic manipulation of extant microorganism, while CSB utilises classic chemical procedures in order to obtain biological structures which are non-existent in nature. The main query concerning CSB is the philosophical question: why did nature do this, and not that? The idea then is to synthesise alternative structures in order to understand why nature operated in such a particular way. We briefly present here some various examples of CSB, including those cases of nucleic acids synthesised with pyranose instead of ribose, and proteins with a reduced alphabet of amino acids; also we report the developing research on the "never born proteins" (NBP) and "never born RNA" (NBRNA), up to the minimal cell project, where the issue is the preparation of semi-synthetic cells that can perform the basic functions of biological cells.

  12. Optical synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Ilovitsh, Asaf; Zach, Shlomo; Zalevsky, Zeev

    2013-06-01

    A method is proposed for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained via a two-step process. First, three low resolution differently defocused images are captured and the optical phase is retrieved using an improved iterative Gershberg-Saxton based algorithm. The phase retrieval allows numerical back propagation of the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the synthetic aperture radar in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated via Matlab simulation as well as through laboratory experiment.

  13. Synthetic surgical gloves.

    PubMed

    2002-06-01

    Surgical gloves are used by healthcare workers to protect them against bloodborne pathogens and other potential infectants and to prevent wound contamination in patients. In response to the increasing prevalence of allergies to natural rubber latex (NRL) among patients and medical staff, the trend toward purchasing gloves made of synthetic materials is on the rise. However, latex continues to dominate the market, and some people still perceive synthetic gloves as providing less protection and being less comfortable than NRL gloves. For this Update Evaluation, we present our findings for three newly evaluated glove models from three manufacturers and summarize our findings for the seven previously evaluated models that are still on the market. (Our earlier Evaluation was published in the February-March 2000 Health Devices.) As in the previous Evaluation, our ratings are based on the gloves' barrier effectiveness--that is, their resistance to viral penetration and their durability--and comfort. We also compared these characteristics of the synthetic gloves to those of NRL gloves. We found that all the evaluated gloves offer adequate barrier protection but that their level of comfort varies considerably. We rate three models Preferred, five models Acceptable, and two models Not Recommended. PMID:12116503

  14. Synthetic biology in plastids.

    PubMed

    Scharff, Lars B; Bock, Ralph

    2014-06-01

    Plastids (chloroplasts) harbor a small gene-dense genome that is amenable to genetic manipulation by transformation. During 1 billion years of evolution from the cyanobacterial endosymbiont to present-day chloroplasts, the plastid genome has undergone a dramatic size reduction, mainly as a result of gene losses and the large-scale transfer of genes to the nuclear genome. Thus the plastid genome can be regarded as a naturally evolved miniature genome, the gradual size reduction and compaction of which has provided a blueprint for the design of minimum genomes. Furthermore, because of the largely prokaryotic genome structure and gene expression machinery, the high transgene expression levels attainable in transgenic chloroplasts and the very low production costs in plant systems, the chloroplast lends itself to synthetic biology applications that are directed towards the efficient synthesis of green chemicals, biopharmaceuticals and other metabolites of commercial interest. This review describes recent progress with the engineering of plastid genomes with large constructs of foreign or synthetic DNA, and highlights the potential of the chloroplast as a model system in bottom-up and top-down synthetic biology approaches.

  15. Determination of synthetic food dyes by capillary electrophoresis.

    PubMed

    Suzuki, S; Shirao, M; Aizawa, M; Nakazawa, H; Sasa, K; Sasagawa, H

    1994-10-01

    A method for the determination of synthetic tar dyes used as food additives using capillary electrophoresis with photodiode-array detection was investigated. The dyes Erythrosine (R-3), Phloxine (R-104), Rose Bengal (R-105), Acid Red (R-106), Amaranth (R-2), New Coccine (R-102) and Allura Red AC (R-40) were separated on a capillary column (50 cm x 75 microns I.D.) and identified from the absorbance spectra of each peak. The electrophoresis buffer used was a mixture of 25 mM sodium phosphate buffer and 25 mM sodium borate buffer (1:1) (pH 8.0) containing 10 mM sodium dodecyl sulfate (SDS). Substitution of beta-cyclodextrin for SDS in the electrolyte buffer was effective for the separation of R-2 and R-102. This modified method could be employed as an additional assay method for these two dyes.

  16. Comparing the activity of aluminum in two B horizons developed from volcanic ash deposits in Japan, dominated by short-range ordered aluminosilicates and crystalline clay minerals, respectively

    NASA Astrophysics Data System (ADS)

    Yagasaki, Yasumi; Mulder, Jan; Okazaki, Masanori

    2006-01-01

    Mechanisms controlling the activity of free aluminum (Al) in Bw1 horizons of soils developed from volcanic ash deposits in Japan were investigated by means of acid-base titrations and kinetic studies. In a Bw1 horizon, with a high content of acid-oxalate extractable Al, soil solution reached equilibrium with short-range ordered aluminosilicates in the order of days. Relatively fast kinetics of the release and precipitation of Al and Si indicate a high reactivity of short-range ordered aluminosilicates in the soil. In the Bw1 horizon of an adjacent soil, with a high content of crystalline clay minerals like halloysite and interlayered vermiculite, solution remained well undersaturated with respect to short-range ordered aluminosilicates and aluminum hydroxide. Apparent equilibrium with respect to halloysite occurred after more than 30 days. This halloysite ( logKso0=3.74±0.02 (25 °C)) has a solubility that is less than that reported in the literature ( logKso0=4.36 (25°C)). Our findings suggest that different reactive aluminosilicates may control the activity of free Al in sub-surface horizons of volcanic ash soils with different mineralogy.

  17. Sodium bisulfate poisoning

    MedlinePlus

    ... in large amounts. This article discusses poisoning from swallowing sodium bisulfate. This article is for information only. ... Symptoms from swallowing more than a tablespoon of this acid may include: Burning pain in the mouth Chest pain from burns ...

  18. Sodium Polystyrene Sulfonate

    MedlinePlus

    ... is used to treat hyperkalemia (increased amounts of potassium in the body). Sodium polystyrene sulfonate is in a class of medications called potassium-removing agents. It works by removing excess potassium ...

  19. Enhancing stability and oxidation activity of cytochrome C by immobilization in the nanochannels of mesoporous aluminosilicates.

    PubMed

    Lee, Chia-Hung; Lang, Jun; Yen, Chun-Wan; Shih, Pei-Chun; Lin, Tien-Sung; Mou, Chung-Yuan

    2005-06-30

    Hydrothermally stable and structrurally ordered mesoporous and microporous aluminosilicates with different pore sizes have been synthesized to immobilize cytochrome c (cyt c): MAS-9 (pore size 90 A), MCM-48-S (27 A), MCM-41-S (25 A), and Y zeolites (7.4 A). The amount of cyt c adsorption could be increased by the introduction of aluminum into the framework of pure silica materials. Among these mesoprous silicas (MPS), MAS-9 showed the highest loading capacity due to its large pore size. However, cyt c immobilized in MAS-9 could undergo facile unfolding during hydrothermal treatments. MCM-41-S and MCM-48-S have the pore sizes that match well the size of cyt c (25 x 25 x 37 A). Hence the adsorbed cyt c in these two medium pore size MPS have the highest hydrothermal stability and overall catalytic activity. On the other hand, the pore size of NaY zeolite is so small that cyt c is mostly adsorbed only on the outer surface and loses its enzymatic activity rapidly. The improved stability and high catalytic activity of cyt c immobilized in MPS are attributed to the electrostatic attraction between the pore surface and cyt c and the confinement provided by nanochannels. We further observed that cyt c immobilized in MPS exists in both high and low spin states, as inferred from the ESR and UV-vis studies. This is different from the native cyt c, which shows primarily the low spin state. The high spin state arises from the replacement of Met-80 ligands of heme Fe (III) by water or silanol group on silica surface, which could open up the heme groove for easy access of oxidants and substrates to iron center and facilitate the catalytic activity. In the catalytic study, MAS-9-cyt c showed the highest specific activity toward the oxidation of polycyclic aromatic hydrocarbons (PAHs), which arises from the fast mass transfer rate of reaction substrate due to its large pore size. For pinacyanol (a hydrophilic substrate), MCM-41-S-cyt c and MCM-48-S-cyt c showed higher specific

  20. Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

    PubMed

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and P<0.001, respectively). This study showed that aluminosilicate sol-gel dip coating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain.

  1. Sol–gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain

    PubMed Central

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol–gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia–porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and P<0.001, respectively). This study showed that aluminosilicate sol–gel dip coating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain. PMID:27478376

  2. Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

    PubMed

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and P<0.001, respectively). This study showed that aluminosilicate sol-gel dip coating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain. PMID:27478376

  3. Opportunities in plant synthetic biology.

    PubMed

    Cook, Charis; Martin, Lisa; Bastow, Ruth

    2014-05-01

    Synthetic biology is an emerging field uniting scientists from all disciplines with the aim of designing or re-designing biological processes. Initially, synthetic biology breakthroughs came from microbiology, chemistry, physics, computer science, materials science, mathematics, and engineering disciplines. A transition to multicellular systems is the next logical step for synthetic biologists and plants will provide an ideal platform for this new phase of research. This meeting report highlights some of the exciting plant synthetic biology projects, and tools and resources, presented and discussed at the 2013 GARNet workshop on plant synthetic biology.

  4. Opportunities in plant synthetic biology.

    PubMed

    Cook, Charis; Martin, Lisa; Bastow, Ruth

    2014-05-01

    Synthetic biology is an emerging field uniting scientists from all disciplines with the aim of designing or re-designing biological processes. Initially, synthetic biology breakthroughs came from microbiology, chemistry, physics, computer science, materials science, mathematics, and engineering disciplines. A transition to multicellular systems is the next logical step for synthetic biologists and plants will provide an ideal platform for this new phase of research. This meeting report highlights some of the exciting plant synthetic biology projects, and tools and resources, presented and discussed at the 2013 GARNet workshop on plant synthetic biology. PMID:24502956

  5. Striking role of non-bridging oxygen on glass transition temperature of calcium aluminosilicate glass-formers

    SciTech Connect

    Bouhadja, M.; Jakse, N.; Pasturel, A.

    2014-06-21

    Molecular dynamics simulations are used to study the structural and dynamic properties of calcium aluminosilicate, (CaO-Al{sub 2}O{sub 3}){sub 1−x}(SiO{sub 2}){sub x}, glass formers along three joins, namely, R = 1, 1.57, and 3, in which the silica content x can vary from 0 to 1. For all compositions, we determined the glass-transition temperature, the abundances of the non-bridging oxygen, triclusters, and AlO{sub 5} structural units, as well as the fragility from the temperature evolution of the α-relaxation times. We clearly evidence the role played by the non-bridging oxygen linked either to Al atoms or Si atoms in the evolution of the glass-transition temperature as well as of the fragility as a function of silica content along the three joins.

  6. Structural, vibrational, and elastic properties of a calcium aluminosilicate glass from molecular dynamics simulations: The role of the potential

    SciTech Connect

    Bauchy, M.

    2014-07-14

    We study a calcium aluminosilicate glass of composition (SiO{sub 2}){sub 0.60}(Al{sub 2}O{sub 3}){sub 0.10}(CaO){sub 0.30} by means of molecular dynamics. To this end, we conduct parallel simulations, following a consistent methodology, but using three different potentials. Structural and elastic properties are analyzed and compared to available experimental data. This allows assessing the respective abilities of the potentials to produce a realistic glass. We report that, although all these potentials offer a reasonable glass structure, featuring tricluster oxygen atoms, their respective vibrational and elastic predictions differ. This allows us to draw some general conclusions about the crucial role, or otherwise, of the interaction potential in silicate systems.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  8. A molecular dynamics study of the interaction of oleate and dodecylammonium chloride surfactants with complex aluminosilicate minerals.

    PubMed

    Rai, Beena; Sathish, P; Tanwar, Jyotsna; Pradip; Moon, K S; Fuerstenau, D W

    2011-10-15

    Surface characteristics of complex aluminosilicate minerals like spodumene [LiAl(SiO(3))(2)], jadeite [NaAl(SiO(3))(2)], feldspar [KAlSi(3)O(8)], and muscovite [K(2)Al(4)(Al(2)Si(6)O(20))(OH)(4)]) are modeled. Surface energies are computed for the cleavage planes of these minerals. Adsorption mechanisms of anionic chemisorbing type oleate and cationic physisorbing type dodecylammonium chloride molecules on two different crystal planes, that is (110) and (001), of spodumene and jadeite are studied in terms of the surface-surfactant interaction energies computed using molecular dynamics (MD) simulations. The conclusions drawn from purely theoretical computations match remarkably well with our experimental results.

  9. X-ray and MAS NMR characterization of the thermal transformation of Li(Na)-Y zeolite to lithium aluminosilicates

    SciTech Connect

    Subramanian, M.A.; Corbin, D.R.; Farlee, R.D.

    1986-12-01

    The high temperature thermal transformation of Li-exchanged Na-Y zeolite has been investigated by X-ray diffraction and /sup 29/Si MAS NMR studies. At 700/sup 0/C, the zeolite was transformed into an amorphous phase and upon further heating to 800/sup 0/C, formation of lithium aluminosilicate with high-quartz structure, in addition to an amorphous phase, was noted. When heated above 900/sup 0/C, the high-quartz structure was transformed into a ..beta..-spodumene related solid solution. X-ray and MAS NMR studies indicate the ..beta..-spodumene solid solution formed has the composition close to (Li/sub 0.23/Na/sub 0.06/)A iota /sub 0.29/Si/sub 0.71/O/sub 2/, which is in agreement with chemical analysis.

  10. Dietary sodium intake, airway responsiveness, and cellular sodium transport.

    PubMed

    Tribe, R M; Barton, J R; Poston, L; Burney, P G

    1994-06-01

    Both epidemiologic and experimental evidence suggest that a high dietary sodium intake may increase airway responsiveness, but no adequate explanation exists of how changes in sodium intake might lead to increased responsiveness. This investigation was carried out to study dietary sodium intake and airway response to methacholine in relation to cellular sodium transport in 52 young men. Airway response to methacholine was associated with urinary sodium excretion when subjects were on normal sodium intake. Airway responsiveness in patients with mild asthma correlated with the furosemide-insensitive influx of sodium into peripheral leukocytes stimulated by autologous serum, but there was no relation between this influx and 24-h urinary sodium excretion. In a separate investigation, serum from subjects with increased airway responsiveness caused an increase in the sodium influx and sodium content of leukocytes from nonatopic subjects. The magnitude of the furosemide-insensitive, serum stimulated influx was related to the degree of airway responsiveness of the serum donor, as was the increase in intracellular sodium content. Neither was related to the 24-h urinary sodium excretion of the donor. Patients with airway hyperresponsiveness have an increased sodium influx into cells stimulated by a serum-borne factor. This is independent of the effect of added dietary sodium on airway responsiveness.

  11. Aluminosilicates with varying alumina-silica ratios: synthesis via a hybrid sol-gel route and structural characterisation.

    PubMed

    Nampi, Padmaja Parameswaran; Moothetty, Padmanabhan; Berry, Frank John; Mortimer, Michael; Warrier, Krishna Gopakumar

    2010-06-01

    Aluminosilicates with varying Al2O3:SiO2 molar ratios (3:1, 3:2, 3:3 and 3:4) have been synthesized using a hybrid sol-gel route using boehmite sol as the precursor for alumina and tetraethyl orthosilicate (TEOS) as the precursor for silica. The synthesis of boehmite sol from aluminium nitrate, and its use as the alumina precursor, is cost effective compared to alkoxide precursors. Structural aspects, including bonding and coordination, are studied in detail for samples calcined in the temperature range 400-1400 °C using both NMR and FTIR spectroscopy: the results are correlated with phase formation data (spinel and high temperature phases) obtained from XRD and thermal analysis. FTIR results show a broadening of peaks at 800 °C indicating a disordered distribution of octahedral sites caused by crosslinking between AlO6 octahedral and SiO4 tetrahedral units prior to the formation of mullite. (27)Al MAS NMR spectra are consistent with a progressive decrease in the number of AlO6 polyhedra with increasing temperature corresponding to Al in these units being forced to adopt a tetrahedral coordination due to the increasing presence of similarly coordinated Si species. XRD results confirm the formation of pure mullite at 1250 °C for a 3Al2O3:2SiO2 system. At 1400 °C, phase pure mullite is observed for all compositions except 3Al2O3:SiO2 where α-Al2O3 is the major phase with traces of mullite. The synthesis of aluminosilicates through a hybrid sol-gel route and the detailed insight into structural features gained from spectroscopic and diffraction techniques contributes further to the development of these materials in applications ranging from nanocatalysts to high-temperature ceramics.

  12. The direct synthesis of organic and organometallic-containing MICA-type aluminosilicates

    SciTech Connect

    Carrado, K.A.; Awaluddin, A.

    1993-08-01

    Layer-silicate clay structures can provide supramolecular organization for catalysis, chiral reactions, colloid science, and electron transfer. The authors have successfully modified the experimental preparations of several different layer silicates in order to incorporate a wide variety of organic and organometallic molecules in the clay galleries. Synthesis and physical characterization of these materials are described and compared to ion-exchanged natural clay analogs. In addition, the photophysical properties of organometallic Ru(II) complexes incorporated by direct hydrothermal crystallization into synthetic clays were measured. 3 tabs, 21 refs.

  13. A study of the titrimetric potassium silicofluoride method for determination of silica in aluminosilicate materials.

    PubMed

    Sinha, B C; Saha, M R; Roy, S K

    1979-09-01

    A critical study of the titrimetric potassium silicofluoride method for determination of silica reveals that quantitative precipitation of the sificofluoride is possible in 3.5-7.5N acid containing 1% sodium fluoride and >/ 12% potassium chloride. An aqueous wash solution (pH approximately 5.3) containing 0.1% sodium fluoride and 12% potassium chloride has been found ideal for washing the precipitate without significant hydrolysis even at 35 degrees C. The interference of large amounts of aluminium (up to 160 mg of Al(2)O(3)) is eliminated by precipitating the silicofluoride in 6-7.5N acid solution, the aluminium then forming practically no fluoro-complex, because of extensive protonation of fluoride. Interference by large amounts of boron (up to 160 mg of B(2)O(3)) is eliminated by precipitating silicofluoride with the minimum permissible potassium chloride concentration (12%) and washing with the aqueous wash solution at room temperature. Nitrazene Yellow has been used as a more sensitive indicator.

  14. A study of the titrimetric potassium silicofluoride method for determination of silica in aluminosilicate materials.

    PubMed

    Sinha, B C; Saha, M R; Roy, S K

    1979-09-01

    A critical study of the titrimetric potassium silicofluoride method for determination of silica reveals that quantitative precipitation of the sificofluoride is possible in 3.5-7.5N acid containing 1% sodium fluoride and > trg 12% potassium chloride. An aqueous wash solution (pH approximately 5.3) containing 0.1% sodium fluoride and 12% potassium chloride has been found ideal for washing the precipitate without significant hydrolysis even at 35 degrees C. The interference of large amounts of aluminium (up to 160 mg of Al(2)O(3)) is eliminated by precipitating the silicofluoride in 6-7.5N acid solution, the aluminium then forming practically no fluoro-complex, because of extensive protonation of fluoride. Interference by large amounts of boron (up to 160 mg of B(2)O(3)) is eliminated by precipitating silicofluoride with the minimum permissible potassium chloride concentration (12%) and washing with the aqueous wash solution at room temperature. Nitrazene Yellow has been used as a more sensitive indicator.

  15. Analog synthetic biology.

    PubMed

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  16. Analog synthetic biology

    PubMed Central

    Sarpeshkar, R.

    2014-01-01

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog–digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA–protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  17. DDT, pyrethrins, pyrethroids and insect sodium channels.

    PubMed

    Davies, T G E; Field, L M; Usherwood, P N R; Williamson, M S

    2007-03-01

    The long term use of many insecticides is continually threatened by the ability of insects to evolve resistance mechanisms that render the chemicals ineffective. Such resistance poses a serious threat to insect pest control both in the UK and worldwide. Resistance may result from either an increase in the ability of the insect to detoxify the insecticide or by changes in the target protein with which the insecticide interacts. DDT, the pyrethrins and the synthetic pyrethroids (the latter currently accounting for around 17% of the world insecticide market), act on the voltage-gated sodium channel proteins found in insect nerve cell membranes. The correct functioning of these channels is essential for normal transmission of nerve impulses and this process is disrupted by binding of the insecticides, leading to paralysis and eventual death. Some insect pest populations have evolved modifications of the sodium channel protein which prevent the binding of the insecticide and result in the insect developing resistance. Here we review some of the work (done at Rothamsted Research and elsewhere) that has led to the identification of specific residues on the sodium channel that may constitute the DDT and pyrethroid binding sites.

  18. Phase 2 THOR Steam Reforming Tests for Sodium Bearing Waste Treatment

    SciTech Connect

    Nicholas R. Soelberg

    2004-01-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste is stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Steam reforming is a candidate technology being investigated for converting the waste into a road ready waste form that can be shipped to the Waste Isolation Pilot Plant in New Mexico for interment. A steam reforming technology patented by Studsvik, Inc., and licensed to THOR Treatment Technologies has been tested in two phases using a Department of Energy-owned fluidized bed test system located at the Science Applications International Corporation (SAIC) Science and Technology Applications Research Center located in Idaho Falls, Idaho. The Phase 1 tests were reported earlier in 2003. The Phase 2 tests are reported here. For Phase 2, the process feed rate, stoichiometry, and chemistry were varied to identify and demonstrate process operation and product characteristics under different operating conditions. Two test series were performed. During the first series, the process chemistry was designed to produce a sodium carbonate product. The second series was designed to produce a more leach-resistant, mineralized sodium aluminosilicate product. The tests also demonstrated the performance of a MACT-compliant off-gas system.

  19. Sodium sulfur battery seal

    DOEpatents

    Mikkor, Mati

    1981-01-01

    This disclosure is directed to an improvement in a sodium sulfur battery construction in which a seal between various battery compartments is made by a structure in which a soft metal seal member is held in a sealing position by holding structure. A pressure applying structure is used to apply pressure on the soft metal seal member when it is being held in sealing relationship to a surface of a container member of the sodium sulfur battery by the holding structure. The improvement comprises including a thin, well-adhered, soft metal layer on the surface of the container member of the sodium sulfur battery to which the soft metal seal member is to be bonded.

  20. Action of the pyrethroid insecticide cypermethrin on rat brain IIa sodium channels expressed in xenopus oocytes.

    PubMed

    Smith, T J; Soderlund, D M

    1998-12-01

    Pyrethroid insecticides bind to a unique site on voltage-dependent sodium channels and prolong sodium currents, leading to repetitive bursts of action potentials or use-dependent nerve block. To further characterize the site and mode of action of pyrethroids on sodium channels, we injected synthetic mRNA encoding the rat brain IIa sodium channel alpha subunit, either alone or in combination with synthetic mRNA encoding the rat sodium channel beta1 subunit, into oocytes of the frog Xenopus laevis and assessed the actions of the pyrethroid insecticide [1R,cis,alphaS]-cypermethrin on expressed sodium currents by two-electrode voltage clamp. In oocytes expressing only the rat brain IIa alpha subunit, cypermethrin produced a slowly-decaying sodium tail current following a depolarizing pulse. In parallel experiments using oocytes expressing the rat brain IIa alpha subunit in combination with the rat beta1 subunit, cypermethrin produced qualitatively similar tail currents following a depolarizing pulse and also induced a sustained component of the sodium current measured during a step depolarization of the oocyte membrane. The voltage dependence of activation and steady-state inactivation of the cypermethrin-dependent sustained current were identical to those of the peak transient sodium current measured in the absence of cypermethrin. Concentration-response curves obtained using normalized tail current amplitude as an index of the extent of sodium channel modification by cypermethrin revealed that coexpression of the rat brain IIa alpha subunit with the rat beta1 subunit increased the apparent affinity of the sodium channel binding site for cypermethrin by more than 20-fold. These results confirm that the pyrethroid binding site is intrinsic to the sodium channel alpha subunit and demonstrate that coexpression of the rat brain IIa alpha subunit with the rat beta1 subunit alters the apparent affinity of this site for pyrethroids.

  1. Sodium storage and injection system

    NASA Technical Reports Server (NTRS)

    Keeton, A. R. (Inventor)

    1979-01-01

    A sodium storage and injection system for delivering atomized liquid sodium to a chemical reactor employed in the production of solar grade silicon is disclosed. The system is adapted to accommodate start-up, shut-down, normal and emergency operations, and is characterized by (1) a jacketed injection nozzle adapted to atomize liquefied sodium and (2) a supply circuit connected to the nozzle for delivering the liquefied sodium. The supply circuit is comprised of a plurality of replaceable sodium containment vessels, a pump interposed between the vessels and the nozzle, and a pressurizing circuit including a source of inert gas connected with the vessels for maintaining the sodium under pressure.

  2. Progress toward synthetic cells.

    PubMed

    Blain, J Craig; Szostak, Jack W

    2014-01-01

    The complexity of even the simplest known life forms makes efforts to synthesize living cells from inanimate components seem like a daunting task. However, recent progress toward the creation of synthetic cells, ranging from simple protocells to artificial cells approaching the complexity of bacteria, suggests that the synthesis of life is now a realistic goal. Protocell research, fueled by advances in the biophysics of primitive membranes and the chemistry of nucleic acid replication, is providing new insights into the origin of cellular life. Parallel efforts to construct more complex artificial cells, incorporating translational machinery and protein enzymes, are providing information about the requirements for protein-based life. We discuss recent advances and remaining challenges in the synthesis of artificial cells, the possibility of creating new forms of life distinct from existing biology, and the promise of this research for gaining a deeper understanding of the nature of living systems. PMID:24606140

  3. Synthetic antibiofilm peptides.

    PubMed

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26724202

  4. Entraining synthetic genetic oscillators

    NASA Astrophysics Data System (ADS)

    Wagemakers, Alexandre; Buldú, Javier M.; Sanjuán, Miguel A. F.; de Luis, Oscar; Izquierdo, Adriana; Coloma, Antonio

    2009-09-01

    We propose a new approach for synchronizing a population of synthetic genetic oscillators, which consists in the entrainment of a colony of repressilators by external modulation. We present a model where the repressilator dynamics is affected by periodic changes in temperature. We introduce an additional plasmid in the bacteria in order to correlate the temperature variations with the enhancement of the transcription rate of a certain gene. This can be done by introducing a promoter that is related to the heat shock response. This way, the expression of that gene results in a protein that enhances the overall oscillations. Numerical results show coherent oscillations of the population for a certain range of the external frequency, which is in turn related to the natural oscillation frequency of the modified repressilator. Finally we study the transient times related with the loss of synchronization and we discuss possible applications in biotechnology of large-scale production coupled to synchronization events induced by heat shock.

  5. Process for converting sodium nitrate-containing, caustic liquid radioactive wastes to solid insoluble products

    DOEpatents

    Barney, Gary S.; Brownell, Lloyd E.

    1977-01-01

    A method for converting sodium nitrate-containing, caustic, radioactive wastes to a solid, relatively insoluble, thermally stable form is provided and comprises the steps of reacting powdered aluminum silicate clay, e.g., kaolin, bentonite, dickite, halloysite, pyrophyllite, etc., with the sodium nitrate-containing radioactive wastes which have a caustic concentration of about 3 to 7 M at a temperature of 30.degree. C to 100.degree. C to thereby entrap the dissolved radioactive salts in the aluminosilicate matrix. In one embodiment the sodium nitrate-containing, caustic, radioactive liquid waste, such as neutralized Purex-type waste, or salts or oxide produced by evaporation or calcination of these liquid wastes (e.g., anhydrous salt cake) is converted at a temperature within the range of 30.degree. C to 100.degree. C to the solid mineral form-cancrinite having an approximate chemical formula 2(NaAlSiO.sub.4) .sup.. xSalt.sup.. y H.sub.2 O with x = 0.52 and y = 0.68 when the entrapped salt is NaNO.sub.3. In another embodiment the sodium nitrate-containing, caustic, radioactive liquid is reacted with the powdered aluminum silicate clay at a temperature within the range of 30.degree. C to 100.degree. C, the resulting reaction product is air dried eitheras loose powder or molded shapes (e.g., bricks) and then fired at a temperature of at least 600.degree. C to form the solid mineral form-nepheline which has the approximate chemical formula of NaAlSiO.sub.4. The leach rate of the entrapped radioactive salts with distilled water is reduced essentially to that of the aluminosilicate lattice which is very low, e.g., in the range of 10.sup.-.sup.2 to 10.sup.-.sup.4 g/cm.sup.2 -- day for cancrinite and 10.sup.-.sup.3 to 10.sup.-.sup.5 g/cm.sup.2 -- day for nepheline.

  6. Synthetic Genomics and Synthetic Biology Applications Between Hopes and Concerns

    PubMed Central

    König, Harald; Frank, Daniel; Heil, Reinhard; Coenen, Christopher

    2013-01-01

    New organisms and biological systems designed to satisfy human needs are among the aims of synthetic genomics and synthetic biology. Synthetic biology seeks to model and construct biological components, functions and organisms that do not exist in nature or to redesign existing biological systems to perform new functions. Synthetic genomics, on the other hand, encompasses technologies for the generation of chemically-synthesized whole genomes or larger parts of genomes, allowing to simultaneously engineer a myriad of changes to the genetic material of organisms. Engineering complex functions or new organisms in synthetic biology are thus progressively becoming dependent on and converging with synthetic genomics. While applications from both areas have been predicted to offer great benefits by making possible new drugs, renewable chemicals or clean energy, they have also given rise to concerns about new safety, environmental and socio-economic risks – stirring an increasingly polarizing debate. Here we intend to provide an overview on recent progress in biomedical and biotechnological applications of synthetic genomics and synthetic biology as well as on arguments and evidence related to their possible benefits, risks and governance implications. PMID:23997647

  7. Dalapon, sodium salt

    Integrated Risk Information System (IRIS)

    Dalapon , sodium salt ; CASRN 75 - 99 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  8. Chlorite (sodium salt)

    Integrated Risk Information System (IRIS)

    Chlorite ( sodium salt ) ; CASRN 7758 - 19 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarc

  9. Decomposition of Sodium Tetraphenylborate

    SciTech Connect

    Barnes, M.J.

    1998-11-20

    The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate (NaTPB) has been investigated. The focus of the investigation is on the determination of additives and/or variables which influence NaTBP decomposition. This document describes work aimed at providing better understanding into the relationship of copper (II), solution temperature, and solution pH to NaTPB stability.

  10. Sodium sulfur battery seal

    DOEpatents

    Topouzian, Armenag

    1980-01-01

    This invention is directed to a seal for a sodium sulfur battery in which a flexible diaphragm sealing elements respectively engage opposite sides of a ceramic component of the battery which separates an anode compartment from a cathode compartment of the battery.

  11. Clinical overview of nedocromil sodium.

    PubMed

    König, P

    1995-01-01

    Nedocromil sodium is a novel anti-inflammatory agent that has been demonstrated to significantly improve pulmonary function and decrease bronchial hyperreactivity in asthmatic patients. Currently available only as an inhaled drug, nedocromil sodium has an excellent safety profile, the only adverse effect being a slightly unpleasant taste. Nedocromil sodium has been used as a replacement for sustained-release theophylline therapy; the overall efficacy of nedocromil sodium is at least equivalent to that of theophylline, with less adverse effects occurring in those patients treated with nedocromil sodium rather than with theophylline. Nedocromil sodium also appears to be equal in efficacy to low doses of beclomethasone when employed in patients with mild to moderate asthma. Addition of nedocromil sodium to an ongoing regimen of beclomethasone may also allow for reduction in the dosage of inhaled corticosteroid. The overall safety of therapy with nedocromil sodium suggests that it be considered as initial therapy for those patients having mild to moderate asthma.

  12. Synthetic Foveal Imaging Technology

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael; Monacos, Steve; Nikzad, Shouleh

    2009-01-01

    Synthetic Foveal imaging Technology (SyFT) is an emerging discipline of image capture and image-data processing that offers the prospect of greatly increased capabilities for real-time processing of large, high-resolution images (including mosaic images) for such purposes as automated recognition and tracking of moving objects of interest. SyFT offers a solution to the image-data processing problem arising from the proposed development of gigapixel mosaic focal-plane image-detector assemblies for very wide field-of-view imaging with high resolution for detecting and tracking sparse objects or events within narrow subfields of view. In order to identify and track the objects or events without the means of dynamic adaptation to be afforded by SyFT, it would be necessary to post-process data from an image-data space consisting of terabytes of data. Such post-processing would be time-consuming and, as a consequence, could result in missing significant events that could not be observed at all due to the time evolution of such events or could not be observed at required levels of fidelity without such real-time adaptations as adjusting focal-plane operating conditions or aiming of the focal plane in different directions to track such events. The basic concept of foveal imaging is straightforward: In imitation of a natural eye, a foveal-vision image sensor is designed to offer higher resolution in a small region of interest (ROI) within its field of view. Foveal vision reduces the amount of unwanted information that must be transferred from the image sensor to external image-data-processing circuitry. The aforementioned basic concept is not new in itself: indeed, image sensors based on these concepts have been described in several previous NASA Tech Briefs articles. Active-pixel integrated-circuit image sensors that can be programmed in real time to effect foveal artificial vision on demand are one such example. What is new in SyFT is a synergistic combination of recent

  13. Recent advances in synthetic biosafety.

    PubMed

    Simon, Anna J; Ellington, Andrew D

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment. PMID:27635235

  14. Synthetic cannabis and respiratory depression.

    PubMed

    Jinwala, Felecia N; Gupta, Mayank

    2012-12-01

    In recent years, synthetic cannabis use has been increasing in appeal among adolescents, and its use is now at a 30 year peak among high school seniors. The constituents of synthetic cannabis are difficult to monitor, given the drug's easy accessibility. Currently, 40 U.S. states have banned the distribution and use of some known synthetic cannabinoids, and have included these drugs in the Schedule I category. The depressive respiratory effect in humans caused by synthetic cannabis inhalation has not been thoroughly investigated in the medical literature. We are the first to report, to our knowledge, two cases of self-reported synthetic cannabis use leading to respiratory depression and necessary intubation. PMID:23234589

  15. Recent advances in synthetic biosafety

    PubMed Central

    Simon, Anna J.; Ellington, Andrew D.

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment.

  16. Recent advances in synthetic biosafety

    PubMed Central

    Simon, Anna J.; Ellington, Andrew D.

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment. PMID:27635235

  17. Dispersion stabilization of silver nanoparticles in synthetic lung fluid studied under in situ conditions

    SciTech Connect

    MacCuspie, R.I.; Allen, A.J.; Hackley, V.A.

    2014-09-24

    The dispersion stabilization of silver nanoparticles (AgNPs) in synthetic lung fluid was studied to interrogate the effects on colloidal stability due to the principal constituents of the fluid. The colloidal stability of 20 nm citrate-AgNPs dispersed in the presence of each constituent of the synthetic lung fluid (individually, the complete fluid, and without additives) was observed during titration of increasing sodium chloride concentration. A variety of complementary in situ measurement techniques were utilized, including dynamic light scattering, ultraviolet-visible absorption spectroscopy, atomic force microscopy, and small-angle X-ray scattering, which provided a collective set of information that enabled far better understanding of the dispersion behavior in the fluid than any one technique alone. It was observed that AgNPs continued to adsorb bovine serum albumin (BSA) protein from the synthetic lung fluid solution as the sodium chloride concentration increased, until a maximum BSA coating was achieved prior to reaching the physiological sodium chloride concentration of 154 mmol L{sup -1}. BSA was determined to be the constituent of the synthetic lung fluid that is required to provide colloidal stability at high salt loadings, though the phospholipid constituent exerts a subtle effect. Additionally, as AgNPs are a distinctly different class of nanoparticles apart from the carbon nanotubes and titanium dioxide nanoparticles initially reported to be dispersible using this fluid, this work also demonstrates the broad applicability of synthetic lung fluid in providing stable dispersions for engineered nanoparticles for use in biological assays.

  18. Ecotoxicology of synthetic pyrethroids.

    PubMed

    Maund, S J; Campbell, P J; Giddings, J M; Hamer, M J; Henry, K; Pilling, E D; Warinton, J S; Wheeler, J R

    2012-01-01

    In this chapter we review the ecotoxicology of the synthetic pyrethroids (SPs). SPs are potent, broad-spectrum insecticides. Their effects on a wide range of nontarget species have been broadly studied, and there is an extensive database available to evaluate their effects. SPs are highly toxic to fish and aquatic invertebrates in the laboratory, but effects in the field are mitigated by rapid dissipation and degradation. Due to their highly lipophilic nature, SPs partition extensively into sediments. Recent studies have shown that toxicity in sediment can be predicted on the basis of equilibrium partitioning, and whilst other factors can influence this, organic carbon content is a key determining variable. At present for SPs, there is no clear evidence for adverse population-relevant effects with an underlying endocrine mode of action. SPs have been studied intensively in aquatic field studies, and their effects under field conditions are mitigated from those measured in the laboratory by their rapid dissipation and degradation. Studies with a range of test systems have shown consistent aquatic field endpoints across a variety of geographies and trophic states. SPs are also highly toxic to bees and other nontarget arthropods in the laboratory. These effects are mitigated in the field through repellency and dissipation of residues, and recovery from any adverse effects tends to be rapid.

  19. Synthetic retinoids in dermatology

    PubMed Central

    Heller, Elizabeth H.; Shiffman, Norman J.

    1985-01-01

    The potential of vitamin A, or retinol, in the treatment of a variety of skin diseases has long been recognized, but because of serious toxic effects this substance generally could not be used. The recent development and marketing of two relatively nontoxic synthetic analogues, which are known as retinoids, has made it possible to treat some of the diseases that are resistant to standard forms of therapy. Isotretinoin is very effective in cystic and conglobate acne, while etretinate is especially useful in the more severe forms of psoriasis. Good results have also been obtained in other disorders of keratinization. Vitamin A and its derivatives apparently have an antineoplastic effect as well and may come to be used in both the prevention and the treatment of epithelial cancer. In many of these diseases the retinoids act by enhancing the normal differentiation and proliferation of epidermal tissues, but the exact mechanisms are not well understood. Their influence on the intracellular polyamines that control the synthesis of nucleic acids and proteins may be an important factor. Although the retinoids have few serious systemic effects, they are teratogenic, and because they persist in the body their use in women of childbearing potential is limited. ImagesFig. 3 PMID:3158386

  20. Synthetic molecular walkers.

    PubMed

    Leigh, David A; Lewandowska, Urszula; Lewandowski, Bartosz; Wilson, Miriam R

    2014-01-01

    In biological systems, molecular motors have been developed to harness Brownian motion and perform specific tasks. Among the cytoskeletal motor proteins, kinesins ensure directional transport of cargoes to the periphery of the cell by taking discrete steps along microtubular tracks. In the past decade there has been an increasing interest in the development of molecules that mimic aspects of the dynamics of biological systems and can became a starting point for the creation of artificial transport systems.To date, both DNA-based and small-molecule walkers have been developed, each taking advantage of the different chemistries available to them. DNA strollers exploit orthogonal base pairing and utilize strand-displacement reactions to control the relative association of the component parts. Small-molecule walkers take advantage of the reversibility of weak noncovalent interactions as well as the robustness of dynamic covalent bonds in order to transport molecular fragments along surfaces and molecular tracks using both diffusional processes and ratchet mechanisms. Here we review both types of synthetic systems, including their designs, dynamics, and how they are being used to perform functions by controlled mechanical motion at the molecular level.

  1. Computing with synthetic protocells.

    PubMed

    Courbet, Alexis; Molina, Franck; Amar, Patrick

    2015-09-01

    In this article we present a new kind of computing device that uses biochemical reactions networks as building blocks to implement logic gates. The architecture of a computing machine relies on these generic and composable building blocks, computation units, that can be used in multiple instances to perform complex boolean functions. Standard logical operations are implemented by biochemical networks, encapsulated and insulated within synthetic vesicles called protocells. These protocells are capable of exchanging energy and information with each other through transmembrane electron transfer. In the paradigm of computation we propose, protoputing, a machine can solve only one problem and therefore has to be built specifically. Thus, the programming phase in the standard computing paradigm is represented in our approach by the set of assembly instructions (specific attachments) that directs the wiring of the protocells that constitute the machine itself. To demonstrate the computing power of protocellular machines, we apply it to solve a NP-complete problem, known to be very demanding in computing power, the 3-SAT problem. We show how to program the assembly of a machine that can verify the satisfiability of a given boolean formula. Then we show how to use the massive parallelism of these machines to verify in less than 20 min all the valuations of the input variables and output a fluorescent signal when the formula is satisfiable or no signal at all otherwise.

  2. Tailoring the porous hierarchy and the tetrahedral aluminum content by using carboxylate ligands: hierarchically structured macro-mesoporous aluminosilicates from a single molecular source.

    PubMed

    Lemaire, Arnaud; Su, Bao-Lian

    2010-11-16

    A novel yet facile synthesis pathway has been developed for the design of hierarchically structured macro-mesoporous aluminosilicates with high aluminum content at tetrahedral sites using a single molecular bifunctional alkoxide (sec-BuO)(2)-Al-O-Si(OEt)(3) precursor. The use of carboxylate ligands and a highly alkaline media slow down the polymerization rate of the aluminum alkoxide functionality, thus permitting the preservation of the intrinsic Al-O-Si linkage. The hierarchically structured porous aluminosilicate materials present an unprecedented low Si/Al ratio close to 1. Heat treatment applied to the synthesized material seems to favor the incorporation of aluminum into tetrahedral position (intraframework aluminum species). The macro-mesoporosity was spontaneously generated, without the use of any external templating agent, by the hydrodynamic flow of the solvents released during the rapid hydrolysis and condensation processes of this double alkoxide. This method results in materials with an open array of interconnected macrochannels. The synthesized aluminosilicate materials with tailorable macro-mesoporous hierarchy and very high Al content at tetrahedral position hold huge promise in various applications as catalysts, catalysts supports, or adsorbents.

  3. Synthetic biology: lessons from the history of synthetic organic chemistry.

    PubMed

    Yeh, Brian J; Lim, Wendell A

    2007-09-01

    The mid-nineteenth century saw the development of a radical new direction in chemistry: instead of simply analyzing existing molecules, chemists began to synthesize them--including molecules that did not exist in nature. The combination of this new synthetic approach with more traditional analytical approaches revolutionized chemistry, leading to a deep understanding of the fundamental principles of chemical structure and reactivity and to the emergence of the modern pharmaceutical and chemical industries. The history of synthetic chemistry offers a possible roadmap for the development and impact of synthetic biology, a nascent field in which the goal is to build novel biological systems. PMID:17710092

  4. Synthetic biology: Understanding biological design from synthetic circuits

    PubMed Central

    Mukherji, Shankar; van Oudenaarden, Alexander

    2011-01-01

    An important aim of synthetic biology is to uncover the design principles of natural biological systems through the rational design of gene and protein circuits. Here we highlight how the process of engineering biological systems — from synthetic promoters to the control of cell–cell interactions — has contributed to our understanding of how endogenous systems are put together and function. Synthetic biological devices allow us to intuitively grasp the ranges of behavior generated by simple biological circuits, such as linear cascades and interlocking feedback loops, as well as to exert control over natural processes such as gene expression and population dynamics. PMID:19898500

  5. Sorption of As(V) on aluminosilicates treated with Fe(II) nanoparticles.

    PubMed

    Dousová, Barbora; Grygar, Tomás; Martaus, Alexandr; Fuitová, Lucie; Kolousek, David; Machovic, Vladimír

    2006-10-15

    Adsorption of arsenic on clay surfaces is important for the natural and simulated removal of arsenic species from aqueous environments. In this investigation, three samples of clay minerals (natural metakaoline, natural clinoptilolite-rich tuff, and synthetic zeolite) in both untreated and Fe-treated forms were used for the sorption of arsenate from model aqueous solution. The treatment of minerals consisted of exposing them to concentrated solution of Fe(II). Within this process the mineral surface has been laden with Fe(III) oxi(hydroxides) whose high affinity for the As(V) adsorption is well known. In all investigated systems the sorption capacity of Fe(II)-treated sorbents increased significantly in comparison to the untreated material (from about 0.5 to >20.0 mg/g, which represented more than 95% of the total As removal). The changes of Fe-bearing particles in the course of treating process and subsequent As sorption were investigated by the diffuse reflectance spectroscopy and the voltammetry of microparticles. IR spectra of treated and As(V)-saturated solids showed characteristic bands caused by Fe(III)SO(4), Fe(III)O, and AsO vibrations. In untreated As(V)-saturated solids no significant AsO vibrations were observed due to the negligible content of sorbed arsenate.

  6. 21 CFR 184.1736 - Sodium bicarbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium bicarbonate. 184.1736 Section 184.1736 Food... Specific Substances Affirmed as GRAS § 184.1736 Sodium bicarbonate. (a) Sodium bicarbonate (NaHCO3, CAS Reg. No. 144-55-8) is prepared by treating a sodium carbonate or a sodium carbonate and sodium...

  7. 21 CFR 184.1736 - Sodium bicarbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium bicarbonate. 184.1736 Section 184.1736 Food... Specific Substances Affirmed as GRAS § 184.1736 Sodium bicarbonate. (a) Sodium bicarbonate (NaHCO3, CAS Reg. No. 144-55-8) is prepared by treating a sodium carbonate or a sodium carbonate and sodium...

  8. 21 CFR 184.1736 - Sodium bicarbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium bicarbonate. 184.1736 Section 184.1736 Food... Specific Substances Affirmed as GRAS § 184.1736 Sodium bicarbonate. (a) Sodium bicarbonate (NaHCO3, CAS Reg. No. 144-55-8) is prepared by treating a sodium carbonate or a sodium carbonate and sodium...

  9. 21 CFR 184.1733 - Sodium benzoate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1733 Sodium benzoate. (a) Sodium benzoate is the chemical benzoate of soda (C7H5NaO2), produced by the neutralization of benzoic acid with sodium bicarbonate, sodium carbonate, or sodium... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium benzoate. 184.1733 Section 184.1733...

  10. 21 CFR 184.1736 - Sodium bicarbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium bicarbonate. 184.1736 Section 184.1736 Food... Specific Substances Affirmed as GRAS § 184.1736 Sodium bicarbonate. (a) Sodium bicarbonate (NaHCO3, CAS Reg. No. 144-55-8) is prepared by treating a sodium carbonate or a sodium carbonate and sodium...

  11. 21 CFR 184.1736 - Sodium bicarbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium bicarbonate. 184.1736 Section 184.1736 Food... GRAS § 184.1736 Sodium bicarbonate. (a) Sodium bicarbonate (NaHCO3, CAS Reg. No. 144-55-8) is prepared by treating a sodium carbonate or a sodium carbonate and sodium bicarbonate solution with...

  12. Studies on synthesis of alumina nanopowder from synthetic Bayer liquor

    SciTech Connect

    Mazloumi, Mahyar; Arami, Hamed; Khalifehzadeh, Razieh; Sadrnezhaad, S.K. . E-mail: sadrnezh@sharif.edu

    2007-06-05

    Procedure for synthesis of alumina nanopowder from Bayer liquor (synthetic sodium aluminate solution) is investigated. Cooling, ageing and then addition of 3 ml/l Tiron (1,2-dihydroxy-3,5-benzene disulfonic acid disodium salt) to the supersaturated liquor affect purity and fineness of the nanopowder product. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) analyses indicate that purity of the alumina nanopowder increases with the aging time. Experimental observations show that highly pure alumina nanopowders could be produced by direct calcination of cold gelatinous sodium aluminate solution followed by careful washing at a Tiron concentration of 3 ml/l NaOH.

  13. Bistatic synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Yates, Gillian

    Synthetic aperture radar (SAR) allows all-weather, day and night, surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming, and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This thesis examines some of the complications involved in producing high-resolution bistatic SAR imagery. The effect of bistatic operation on resolution is examined from a theoretical viewpoint and analytical expressions for resolution are developed. These expressions are verified by simulation work using a simple 'point by point' processor. This work is extended to look at using modern practical processing engines for bistatic geometries. Adaptations of the polar format algorithm and range migration algorithm are considered. The principal achievement of this work is a fully airborne demonstration of bistatic SAR. The route taken in reaching this is given, along with some results. The bistatic SAR imagery is analysed and compared to the monostatic imagery collected at the same time. Demonstrating high-resolution bistatic SAR imagery using two airborne platforms represents what I believe to be a European first and is likely to be the first time that this has been achieved outside the US (the UK has very little insight into US work on this topic). Bistatic target characteristics are examined through the use of simulations. This also compares bistatic imagery with monostatic and gives further insight into the utility of bistatic SAR.

  14. Synthetic inhibitors of elastase.

    PubMed

    Edwards, P D; Bernstein, P R

    1994-03-01

    For more than two decades investigators around the world, in both academic and industrial institutions, have been developing inhibitors of human neutrophil elastase. A number of very elegant and insightful strategies have been reported. In the case of reversible peptidic inhibitors, this has resulted in the identification of some extremely potent compounds with dissociation constants in the 10(-11) M range. This is quite an accomplishment considering that these low molecular-weight inhibitors are only tri- and tetrapeptides. In the case of the heterocyclic-based inhibitors, the challenge of balancing the heterocycle's inherent reactivity and aqueous stability with the stability of the enzyme-inhibitor adduct has been meet by either using a latent, reactive functionality which is only activated within the enzyme, or by incorporating features which selectively obstruct deacylation but have little effect on the enzyme acylation step. The underlying goal of this research has been the identification of agents to treat diseases associated with HNE. Several animal models have been developed for evaluating the in vivo activity of elastase inhibitors, and compounds have been shown to be effective in all of these models by the intravenous, intratrachael or oral routes of administration. However, only a very small percentage of compounds have possessed all the necessary properties, including lack of toxicity, for progression into the clinic. The peptidyl TFMK ICI 200,880 (25-12) has many of the desired characteristics of a drug to treat the diseases associated with HNE: chemical stability, in vitro and in vivo activity, a long duration of action, and adequate metabolic stability. Currently ICI 200,880 is the only low molecular-weight HNE inhibitor known to be undergoing clinical trials, and may be the compound which finally demonstrates the clinical utility of a synthetic HNE inhibitor. PMID:8189835

  15. Spicing thing up: Synthetic cannabinoids

    PubMed Central

    Spaderna, Max; Addy, Peter H; D’Souza, Deepak Cyril

    2013-01-01

    Rationale Recently, products containing synthetic cannabinoids, collectively referred to as Spice, are increasingly being used recreationally. Objectives The availability, acute subjective effects—including self-reports posted on Erowid—laboratory detection, addictive potential, and regulatory challenges of the Spice phenomenon are reviewed. Results Spice is sold under the guise of potpourri or incense. Unlike THC, the synthetic cannabinoids present in Spice are high-potency, high-efficacy, cannabinoid-receptor full agonists. Since standard urine toxicology does not test for the synthetic cannabinoids in Spice, it is often used by those who want to avoid detection of drug use. These compounds have not yet been subjected to rigorous testing in humans. Acute psychoactive effects include changes in mood, anxiety, perception, thinking, memory, and attention. Adverse effects include anxiety, agitation, panic, dysphoria, psychosis, and bizarre behavior. Psychosis outcomes associated with Spice provide additional data linking cannabinoids and psychosis. Adverse events necessitating intervention by Poison Control Centers, law enforcement, emergency responders, and hospitals are increasing. Despite statutes prohibiting the manufacture, distribution, and sale of Spice products, manufacturers are replacing banned compounds with newer synthetic cannabinoids that are not banned. Conclusions There is an urgent need for better research on the effects of synthetic cannabinoids to help clinicians manage adverse events and to better understand cannabinoid pharmacology in humans. The reported psychosis outcomes associated with synthetic cannabinoids contribute to the ongoing debate on the association between cannabinoids and psychosis. Finally, drug-detection tests for synthetic cannabinoids need to become clinically available. PMID:23836028

  16. Sodium intake and cardiovascular health.

    PubMed

    O'Donnell, Martin; Mente, Andrew; Yusuf, Salim

    2015-03-13

    Sodium is an essential nutrient. Increasing sodium intake is associated with increasing blood pressure, whereas low sodium intake results in increased renin and aldosterone levels. Randomized controlled trials have reported reductions in blood pressure with reductions in sodium intake, to levels of sodium intake <1.5 g/d, and form the evidentiary basis for current population-wide guidelines recommending low sodium intake. Although low sodium intake (<2.0 g/d) has been achieved in short-term feeding clinical trials, sustained low sodium intake has not been achieved by any of the longer term clinical trials (>6-month duration). It is assumed that the blood pressure-lowering effects of reducing sodium intake to low levels will result in large reductions in cardiovascular disease globally. However, current evidence from prospective cohort studies suggests a J-shaped association between sodium intake and cardiovascular events, based on studies from >300 000 people, and suggests that the lowest risk of cardiovascular events and death occurs in populations consuming an average sodium intake range (3-5 g/d). The increased risk of cardiovascular events associated with higher sodium intake (>5 g/d) is most prominent in those with hypertension. A major deficit in the field is the absence of large randomized controlled trials to provide definitive evidence on optimal sodium intake for preventing cardiovascular events. Pending such trials, current evidence would suggest a recommendation for moderate sodium intake in the general population (3-5 g/d), with targeting the lower end of the moderate range among those with hypertension.

  17. Color tunability with temperature and pump intensity in Yb3+/Tm3+ codoped aluminosilicate glass under anti-Stokes excitation.

    PubMed

    Silva, W F; Eliel, G S N; dos Santos, P V; de Araujo, M T; Vermelho, M V D; Udo, P T; Astrath, N G C; Baesso, M L; Jacinto, C

    2010-07-21

    Pump and thermally induced color tunabilities were demonstrated in Yb(3+)/Tm(3+) codoped low silica calcium aluminosilicate (LSCAS) glass under anti-Stokes excitation at 1.064 microm. The effects of pump intensity and sample's temperature on the upconversion emissions and mainly on the color tunabilities (from 800 to 480 nm) were investigated. The results revealed a 20- and a threefold reductions at 800/480 nm ratio as, respectively, the pump intensity and sample's temperature were increased from 27 to 700 kW/cm(2) and from 296 to 577 K. These behaviors with pump intensity and temperature (a strong increase of the 480 nm emission in comparison with the 800 nm one) were attributed to the several efficient processes occurring in the LSCAS system (Yb(3+)-->Tm(3+) energy-transfer processes, easy saturations of the Yb(3+) and Tm(3+) excited states, and radiative emissions). Besides these assigns, the temperature dependence is mainly assigned to the temperature-dependent effective absorption cross section of the ytterbium sensitizer through the so-called multiphonon-assisted anti-Stokes excitation process. Theoretical analyses and fits of the experimental data provided quantitative information. PMID:20649337

  18. Novel aluminosilicate hollow sphere as a catalyst support for methane decomposition to COx-free hydrogen production

    NASA Astrophysics Data System (ADS)

    Awadallah, A. E.; Ahmed, W.; El-Din, M. R. Noor; Aboul-Enein, A. A.

    2013-12-01

    Novel Ni and Co supported on aluminosilicate hollow sphere catalysts were investigated to decompose methane into CO and CO2 free hydrogen and carbon nanotube. The hollow sphere structure was prepared by reverse microemulsion method and then Ni and Co were loaded by the impregnation method. The fresh catalysts and deposited carbon were characterized by several microscopic and spectroscopic techniques. The catalytic results showed that the Co based catalyst exhibited higher activity and durability at longer reaction time, due to the higher number and distribution of metal sites. The hollow sphere structure of the support could protect the metal particles against aggregation during the catalytic reactions. Accordingly, higher metal dispersion, stabilization and catalytic performance were achieved. The formation of nickel silicate is the main reason for the lower decomposition activity of Ni based catalyst at longer reaction time. TEM and Raman spectroscopic data revealed that the Co-based catalyst produced a relatively uniform diameter of MWCNTs with higher crystallinity and graphitization degree compared to the Ni-based catalyst.

  19. Electrical behavior of aluminosilicate glass-ceramic sealants and their interaction with metallic solid oxide fuel cell interconnects

    NASA Astrophysics Data System (ADS)

    Goel, Ashutosh; Tulyaganov, Dilshat U.; Kharton, Vladislav V.; Yaremchenko, Aleksey A.; Ferreira, José M. F.

    A series of alkaline-earth aluminosilicate glass-ceramics (GCs) were appraised with respect to their suitability as sealants for solid oxide fuel cells (SOFCs). The parent composition with general formula Ca 0.9MgAl 0.1La 0.1Si 1.9O 6 was modified with Cr 2O 3 and BaO. The addition of BaO led to a substantial decrease in the total electrical conductivity of the GCs, thus improving their insulating properties. BaO-containing GCs exhibited higher coefficient of thermal expansion (CTE) in comparison to BaO-free GCs. An extensive segregation of oxides of Ti and Mn, components of the Crofer22 APU interconnect alloy, along with negligible formation of BaCrO 4 was observed at the interface between GC/interconnects diffusion couples. Thermal shock resistance and gas-tightness of GC sealants in contact with yttria-stabilized zirconia electrolyte (8YSZ) was evaluated in air and water. Good matching of CTE and strong, but not reactive, adhesion to the solid electrolyte and interconnect, in conjunction with a high level of electrical resistivity, are all advantageous for potential SOFC applications.

  20. Chemical Compatibility of Barium-Calcium-Aluminosilicate Based Sealing Glasses with Ferritic Stainless Steel Interconnect in SOFCs

    SciTech Connect

    Yang, Z Gary; Meinhardt, Kerry D.; Stevenson, Jeffry W.

    2003-08-01

    In most planar SOFC stack designs, the interconnect, which is typically made from a ferritic stainless steel, is hermitically sealed to the ceramic PEN (Positive electrode-Electrolyte-Negative electrode) by a sealing glass. To maintain the structural stability and minimize degradation of the stack performance, the sealing glass must be chemically compatible with the stainless steel interconnect. In this study, a barium-calcium-aluminosilicate (BCAS) based glass-ceramic, specifically developed as a sealant in SOFC stacks, and a ferritic stainless steel (446) were selected as examples to increase the understanding the chemical compatibility issues in SOFC. Evaluation of the interfaces of coupon joints indicated that interactions between the BCAS glass-ceramic and the ferritic stainless steel was dependent on the exposure conditions. At the edges of joints, where oxygen or air was accessible, the interaction often led to the formation of BaCrO4, while in the interior of the joints, chromium or chromia dissolved into the glass to form a thin layer of chromium rich solid solution. It was also found that, in the interior of the joints, the interaction often resulted in the formation of pores aligned along the interface. It appears the pore formation along the interface can be avoided through a pre-heat treatment.

  1. Relations among nonbridging oxygen, optical properties, optical basicity, and color center formation in CaO-MgO aluminosilicate glasses

    SciTech Connect

    Novatski, A.; Steimacher, A.; Medina, A. N.; Bento, A. C.; Baesso, M. L.; Andrade, L. H. C.; Lima, S. M.; Guyot, Y.; Boulon, G.

    2008-11-01

    In this study the relations among nonbridging oxygen (NBO), optical properties, optical basicity, and color center formation in CaO-MgO aluminosilicate glasses were studied. Samples containing (in mol %) 35.9-57.5 of CaO, 16-27.7 of Al{sub 2}O{sub 3}, 7.9-41.6 of SiO{sub 2}, and 6.5-6.9 of MgO were measured by optical absorption and excitation, luminescence, and Raman spectroscopy. The results showed that when the SiO{sub 2} content was increased, the absorption edge shifted toward lower wavelengths and the bonds between O{sup 2-} ions and cations became more covalent. These observations were confirmed by Raman results that showed a decrease in the number of NBO per silicon tetrahedron as a function of SiO{sub 2} content. The results indicate that the effects of higher NBO concentration are the narrowing of the band gap energy and the delocalization of O{sup 2-} electrons, which facilitates the O{sup 2-} electrons to be trapped by anion vacancies and, consequently, forming color centers. The relationship between color center formation and SiO{sub 2} content was confirmed by optical spectroscopic measurements under UV radiation.

  2. Aluminosilicate-based adsorbent in equimolar and non-equimolar binary-component heavy metal removal systems.

    PubMed

    Xu, Meng; Hadi, Pejman; Ning, Chao; Barford, John; An, Kyoung Jin; McKay, Gordon

    2015-01-01

    Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb²⁺ ions selectively. This has been attributed to the higher electronegativity value of Pb²⁺ compared to Cd²⁺ which can be more readily adsorbed on the adsorbent surface, displacing the Cd²⁺ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb²⁺ molar ratio of 30%. Below this threshold value, the Cd²⁺ and Pb²⁺ ions are uptaken simultaneously due to the abundance of Cd²⁺ ions and the availability of adsorption sites at very low Pb²⁺ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications. PMID:26676004

  3. Environmental Weathering of Aluminosilicate Clay Minerals: Solid-State NMR Studies of Transformations Leading to Radionuclide Sequestration

    SciTech Connect

    Mueller, Karl T.; Crosson, Garry; Chorover, Jon; Choi, Sunkyung

    2004-03-28

    Mobilities of radionuclides (such as 137Cs and 90Sr) are governed by their interactions with natural soil particles in the saturated and unsaturated zones at Department of Energy sites. High surface area aluminosilicate clay minerals are a component of the natural soils beneath the leaking waste tanks at these sites and serve as possible radionuclide sorbents. However, due to the characteristics of the contaminant medium (high pH, high Al and high ionic strength), clay minerals are susceptible to transformations during exposure to tank waste leachates. We are currently studying the transformation of clays under specific chemical conditions that mimic the composition of known contaminant solutions. In these studies, specimen clay samples are reacted for varying time periods (up to one year) with simulated tank waste leachate solutions. Mineral dissolution and transformation are followed with solution analysis, x-ray diffraction and a number of other analytical methods. We report here results from 27Al MAS NMR at variable magnetic field strengths (up to 18.8 T), 29Si MAS NMR and 1H/29Si CPMAS NMR and evaluate these results along with those of other parallel analytic studies.

  4. Calcium-Magnesium-Aluminosilicate (CMAS) Infiltration and Cyclic Degradations of Thermal and Environmental Barrier Coatings in Thermal Gradients

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Harder, Bryan; Smialek, Jim; Miller, Robert A.

    2014-01-01

    In a continuing effort to develop higher temperature capable turbine thermal barrier and environmental barrier coating systems, Calcium-Magnesium-Aluminosilicate (CMAS) resistance of the advanced coating systems needs to be evaluated and improved. This paper highlights some of NASA past high heat flux testing approaches for turbine thermal and environmental barrier coatings assessments in CMAS environments. One of our current emphases has been focused on the thermal barrier - environmental barrier coating composition and testing developments. The effort has included the CMAS infiltrations in high temperature and high heat flux turbine engine like conditions using advanced laser high heat flux rigs, and subsequently degradation studies in laser heat flux thermal gradient cyclic and isothermal furnace cyclic testing conditions. These heat flux CMAS infiltration and related coating durability testing are essential where appropriate CMAS melting, infiltration and coating-substrate temperature exposure temperature controls can be achieved, thus helping quantify the CMAS-coating interaction and degradation mechanisms. The CMAS work is also playing a critical role in advanced coating developments, by developing laboratory coating durability assessment methodologies in simulated turbine engine conditions and helping establish CMAS test standards in laboratory environments.

  5. Aluminosilicate-based adsorbent in equimolar and non-equimolar binary-component heavy metal removal systems.

    PubMed

    Xu, Meng; Hadi, Pejman; Ning, Chao; Barford, John; An, Kyoung Jin; McKay, Gordon

    2015-01-01

    Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb²⁺ ions selectively. This has been attributed to the higher electronegativity value of Pb²⁺ compared to Cd²⁺ which can be more readily adsorbed on the adsorbent surface, displacing the Cd²⁺ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb²⁺ molar ratio of 30%. Below this threshold value, the Cd²⁺ and Pb²⁺ ions are uptaken simultaneously due to the abundance of Cd²⁺ ions and the availability of adsorption sites at very low Pb²⁺ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications.

  6. Chemical and physical transformations of aluminosilicate clay minerals due to acid treatment and consequences for heterogeneous ice nucleation.

    PubMed

    Sihvonen, Sarah K; Schill, Gregory P; Lyktey, Nicholas A; Veghte, Daniel P; Tolbert, Margaret A; Freedman, Miriam Arak

    2014-09-25

    Mineral dust aerosol is one of the largest contributors to global ice nuclei, but physical and chemical processing of dust during atmospheric transport can alter its ice nucleation activity. In particular, several recent studies have noted that sulfuric and nitric acids inhibit heterogeneous ice nucleation in the regime below liquid water saturation in aluminosilicate clay minerals. We have exposed kaolinite, KGa-1b and KGa-2, and montmorillonite, STx-1b and SWy-2, to aqueous sulfuric and nitric acid to determine the physical and chemical changes that are responsible for the observed deactivation. To characterize the changes to the samples upon acid treatment, we use X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy. We find that the reaction of kaolinite and montmorillonite with aqueous sulfuric acid results in the formation of hydrated aluminum sulfate. In addition, sulfuric and nitric acids induce large structural changes in montmorillonite. We additionally report the supersaturation with respect to ice required for the onset of ice nucleation for these acid-treated species. On the basis of lattice spacing arguments, we explain how the chemical and physical changes observed upon acid treatment could lead to the observed reduction in ice nucleation activity. PMID:25211030

  7. Self-rolling of an aluminosilicate sheet into a single walled imogolite nanotube: The role of the hydroxyl arrangement

    SciTech Connect

    González, R. I.; Rogan, J.; Valdivia, J. A.; Munoz, F.; Valencia, F.; Ramírez, M.; Kiwi, M.; Ramírez, R.

    2015-12-31

    Imogolite is an inorganic nanotube, that forms naturally in weathered volcanic ashes, and it can be synthesized in nearly monodisperse diameters. However, long after its successful synthesis, the details of the way it is achieved are not fully understood. Here we elaborate on a model of its synthesis, which starts with a planar aluminosilicate sheet that is allowed to evolve freely, by means of classical molecular dynamics, until it achieves its minimum energy configuration. The minimal structures that the system thus adopts are tubular, scrolled, and more complex conformations, depending mainly on temperature as a driving force. Here we focus on the effect that the arrangement of the hydroxyl groups in the inner wall of the nanotube have on the minimal nanotubular configurations that we obtain are monodispersed in diameter, and quite similar to both from the those of weathered natural volcanic ashes, and to the ones that are synthesized in the laboratory. In this contribution we expand on the atomic mechanisms behind those behaviors.

  8. Self-rolling of an aluminosilicate sheet into a single walled imogolite nanotube: The role of the hydroxyl arrangement

    NASA Astrophysics Data System (ADS)

    González, R. I.; Ramírez, R.; Rogan, J.; Valdivia, J. A.; Munoz, F.; Valencia, F.; Ramírez, M.; Kiwi, M.

    2015-12-01

    Imogolite is an inorganic nanotube, that forms naturally in weathered volcanic ashes, and it can be synthesized in nearly monodisperse diameters. However, long after its successful synthesis, the details of the way it is achieved are not fully understood. Here we elaborate on a model of its synthesis, which starts with a planar aluminosilicate sheet that is allowed to evolve freely, by means of classical molecular dynamics, until it achieves its minimum energy configuration. The minimal structures that the system thus adopts are tubular, scrolled, and more complex conformations, depending mainly on temperature as a driving force. Here we focus on the effect that the arrangement of the hydroxyl groups in the inner wall of the nanotube have on the minimal nanotubular configurations that we obtain are monodispersed in diameter, and quite similar to both from the those of weathered natural volcanic ashes, and to the ones that are synthesized in the laboratory. In this contribution we expand on the atomic mechanisms behind those behaviors.

  9. Demonstrating the benefits and pitfalls of various acidity characterization techniques by a case study on bimodal aluminosilicates.

    PubMed

    Van Oers, Cynthia J; Góra-Marek, Kinga; Prelot, Bénédicte; Datka, Jerzy; Meynen, Vera; Cool, Pegie

    2014-02-25

    A new combination of a volumetric with a dynamic method to investigate the acidity properties of aluminosilicates is introduced. In the first step, the total acidity is determined volumetrically by the measurement of two-cycle adsorption (TCA) isotherms with ammonia as a probe, directly followed by a dynamic temperature-programmed desorption (TPD) experiment to define the acid strength distribution. Furthermore, the results obtained by the new direct combination of TCA and TPD are validated by comparison with an in-situ FTIR (Fourier transform infrared) study with the same probe molecule on the same materials. Both acidity characterization techniques are compared, and we comment on their complementarity, benefits, and pitfalls. The material under investigation is a new type of bimodal microporous and mesoporous material with zeolitic characteristics, synthesized by a mesotemplate-free method. The acidic nature of the novel material is compared to two reference materials: a crystalline zeolite and a mesoporous aluminum incorporated mesocellular foam (Al-MCF) with amorphous characteristics.

  10. Bona-fide method for the determination of short range order and transport properties in a ferro-aluminosilicate slag

    NASA Astrophysics Data System (ADS)

    Karalis, Konstantinos T.; Dellis, Dimitrios; Antipas, Georgios S. E.; Xenidis, Anthimos

    2016-07-01

    The thermodynamics, structural and transport properties (density, melting point, heat capacity, thermal expansion coefficient, viscosity and electrical conductivity) of a ferro-aluminosilicate slag have been studied in the solid and liquid state (1273–2273 K) using molecular dynamics. The simulations were based on a Buckingham-type potential, which was extended here, to account for the presence of Cr and Cu. The potential was optimized by fitting pair distribution function partials to values determined by Reverse Monte Carlo modelling of X-ray and neutron diffraction experiments. The resulting short range order features and ring statistics were in tight agreement with experimental data and created consensus for the accurate prediction of transport properties. Accordingly, calculations yielded rational values both for the average heat capacity, equal to 1668.58 J/(kg·K), and for the viscosity, in the range of 4.09–87.64 cP. The potential was consistent in predicting accurate values for mass density (i.e. 2961.50 kg/m3 vs. an experimental value of 2940 kg/m3) and for electrical conductivity (5.3–233 S/m within a temperature range of 1273.15–2273.15 K).

  11. Effects of various types of aluminosilicates and aflatoxin B1 on aflatoxin toxicity, chick performance, and mineral status.

    PubMed

    Scheideler, S E

    1993-02-01

    In vivo and in vitro trials were conducted to test the efficacy of four aluminosilicates (AS) (Ethacal feed component, Novasil, Perlite, and Zeobrite) to sorb aflatoxin B1 (AFB1) and alleviate aflatoxicosis in broiler chicks. Percentage sorption capacity of AS to radiolabeled AFB1 dissolved in methanol varied from 2 to 60%, whereas percentage sorption in intestinal contents varied from 0 to 40.0% according to type of AS tested. Intestinal contents alone sorbed 42% radiolabeled AFB1. Novasil and Zeobrite exhibited the highest rates of sorption (55 and 60%, respectively) in methanol. An in vivo study compared the four types of AS in combination with 0 or 2.5 ppm AFB1 fed to day-old chicks (two pens of six chicks per treatment) to 3 wk of age. Diet effects on body weight, liver lipid, bone ash, and serum Ca, P, Na, K, and Cl were measured. The AFB1 significantly decreased 2- and 3-wk body weight, and a significant interaction effect of AS and AFB1 on bird weight occurred at 2 and 3 wk of age. Three of the four AS tested alleviated the growth depression caused by AFB1. Liver lipids percentage was increased in the AFB1-treated chicks, but this effect was suppressed by three of the AS. Bone ash was not affected by AFB1 and was increased by Novasil and decreased by Ethacal. Ethacal, Novasil, Perlite, and Zeobrite all tended to decrease serum Cl, regardless of AFB1 treatment.

  12. Microstructure-property relationships of SiC fiber-reinforced magnesium aluminosilicates. 2: Mechanical properties and failure characteristics

    SciTech Connect

    Kumar, A.; Knowles, K.M.

    1996-07-01

    Interfacial frictional shear stresses, flexural properties and failure mechanisms are reported for two magnesium aluminosilicates unidirectionally reinforced with Nicalon SiC fibers. Composites A and B were hot-pressed at 1,500 and 920 C, respectively. High values of interfacial frictional shear stresses inferred from Marshall`s analysis of the micro-indentation technique could be attributed in part to the presence of compressive radial stresses at the fiber-matrix interfaces. Although both composites failed non-catastrophically in symmetrical four point bend testing at room temperature, the failure modes were different. Extensive matrix microcracking, fiber failure and then fiber pull-put were commonly observed in composite A. Failure modes in composite B included the formation of a limited number of matrix cracks, the failure of fibers in the matrix crack front and progressive delamination. The observations demonstrate that the mechanical properties, the interfacial frictional shear stresses and the failure mechanisms of both composites are governed by their microstructural features, in particular the chemistry and structure of the matrix-fiber interfacial region.

  13. Resolving the aluminum ordering in aluminosilicates by a combined experimental/theoretical study of 27Al electric field gradients.

    PubMed

    Rocquefelte, Xavier; Clabau, Frédéric; Paris, Michael; Deniard, Philippe; Le Mercier, Thierry; Jobic, Stéphane; Whangbo, Myung-Hwan

    2007-07-01

    The discrimination between atomic species in light-element materials is a challenging question. An archetypal example is the resolution of the Al/Si ordering in aluminosilicates. Only an average long-range order can be deduced from powder X-ray or neutron diffraction, while magic-angle-spinning NMR provides an accurate picture of the short-range order. The long- and short-range orders thus obtained usually differ, hence raising the question of whether the difference between local and extended orders is intrinsic or caused by the difficulty of obtaining an accurate picture of the long-range order from diffraction techniques. In this communication we resolve this question for the monoclinic phases of BaAl2Si2O8 and SrAl2Si2O8 on the basis of 27Al NMR measurements and ab initio simulation of electric field gradient. Although the long- and short-range orders deduced from our XRD and NMR experiments differ, they become similar when the XRD atomic positions are optimized by ab initio electronic structure calculations.

  14. Ordered three- and five-ply nanocomposites from ABC block terpolymer microphase separation with niobia and aluminosilicate sols

    PubMed Central

    Stefik, Morgan; Mahajan, Surbhi; Sai, Hiroaki; Epps, Thomas H.; Bates, Frank S.; Gruner, Sol M; DiSalvo, Francis J.; Wiesner, Ulrich

    2009-01-01

    We report the first use of a non-frustrated block terpolymer for the synthesis of highly ordered oxide nanocomposites containing multiple plies. The morphological behavior of 15 ISO-oxide nanocomposites was investigated spanning a large range of compositions along the ƒI=ƒS isopleth using aluminosilicate and niobia sols. Morphologies were determined by TEM and SAXS measurements. Four morphologies were identified, including core-shell hexagonal, core-shell double gyroid, three-domain lamellae, and core-shell inverse-hexagonal, in order of increasing O+oxide vol fraction. All of the resulting nanocomposites had three- or five-ply morphologies containing domains that were continuous in one, two, or three dimensions. The five-ply core-shell double gyroid phase was only found to be stable when the O+oxide domain was a minority. Removal of the polymer enabled simple and direct synthesis of mesoporous oxide materials while retaining the ordered network structure. We believe that advances in the synthesis of multi-ply nanocomposites will lead to advanced materials and devices containing multiple plies of functional materials. PMID:20209023

  15. Bona-fide method for the determination of short range order and transport properties in a ferro-aluminosilicate slag.

    PubMed

    Karalis, Konstantinos T; Dellis, Dimitrios; Antipas, Georgios S E; Xenidis, Anthimos

    2016-01-01

    The thermodynamics, structural and transport properties (density, melting point, heat capacity, thermal expansion coefficient, viscosity and electrical conductivity) of a ferro-aluminosilicate slag have been studied in the solid and liquid state (1273-2273 K) using molecular dynamics. The simulations were based on a Buckingham-type potential, which was extended here, to account for the presence of Cr and Cu. The potential was optimized by fitting pair distribution function partials to values determined by Reverse Monte Carlo modelling of X-ray and neutron diffraction experiments. The resulting short range order features and ring statistics were in tight agreement with experimental data and created consensus for the accurate prediction of transport properties. Accordingly, calculations yielded rational values both for the average heat capacity, equal to 1668.58 J/(kg·K), and for the viscosity, in the range of 4.09-87.64 cP. The potential was consistent in predicting accurate values for mass density (i.e. 2961.50 kg/m(3) vs. an experimental value of 2940 kg/m(3)) and for electrical conductivity (5.3-233 S/m within a temperature range of 1273.15-2273.15 K). PMID:27455915

  16. Color tunability with temperature and pump intensity in Yb3+/Tm3+ codoped aluminosilicate glass under anti-Stokes excitation.

    PubMed

    Silva, W F; Eliel, G S N; dos Santos, P V; de Araujo, M T; Vermelho, M V D; Udo, P T; Astrath, N G C; Baesso, M L; Jacinto, C

    2010-07-21

    Pump and thermally induced color tunabilities were demonstrated in Yb(3+)/Tm(3+) codoped low silica calcium aluminosilicate (LSCAS) glass under anti-Stokes excitation at 1.064 microm. The effects of pump intensity and sample's temperature on the upconversion emissions and mainly on the color tunabilities (from 800 to 480 nm) were investigated. The results revealed a 20- and a threefold reductions at 800/480 nm ratio as, respectively, the pump intensity and sample's temperature were increased from 27 to 700 kW/cm(2) and from 296 to 577 K. These behaviors with pump intensity and temperature (a strong increase of the 480 nm emission in comparison with the 800 nm one) were attributed to the several efficient processes occurring in the LSCAS system (Yb(3+)-->Tm(3+) energy-transfer processes, easy saturations of the Yb(3+) and Tm(3+) excited states, and radiative emissions). Besides these assigns, the temperature dependence is mainly assigned to the temperature-dependent effective absorption cross section of the ytterbium sensitizer through the so-called multiphonon-assisted anti-Stokes excitation process. Theoretical analyses and fits of the experimental data provided quantitative information.

  17. CTAB-assisted fabrication of mesoporous composite consisting of wormlike aluminosilicate shell and ordered MSU-S core

    SciTech Connect

    Zhai Shangru; Zheng Junlin; Wu Dong; Sun Yuhan . E-mail: yhsun@sxicc.ac.cn; Deng Feng

    2005-01-15

    Novel mesoporous composites comprised of aluminosilicate shell with wormhole framework structure and well-ordered MSU-S core have been firstly prepared via treatment of MSU-S with NaAlO{sub 2} solution in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The obtained products were thoroughly characterized by XRD, HRTEM, N{sub 2} sorption isotherm, TG-DSC, {sup 27}Al MAS NMR and {sup 29}Si MAS NMR, etc. Characterization results based on these techniques revealed that the introduction of CTAB during the treatment process played a crucial role in the formation of mesoporous composite, otherwise the parent ordered MSU-S would be completely destroyed. Furthermore, aluminum content in the final product determined by ICP and EDAX was significantly increased compared to the parent MSU-S, thus assuming that CTAB added in this modification process led a key role in the introduction of Al into the final solid via self-assembly with additionally added AlO{sub 2}{sup -} and partly dissolved silicate species from the parent MSU-S particles. In addition, acidity and catalytic performance of the prepared mesoporous composite were also substantially improved in comparison to the parent MSU-S sample.

  18. Bona-fide method for the determination of short range order and transport properties in a ferro-aluminosilicate slag

    PubMed Central

    Karalis, Konstantinos T.; Dellis, Dimitrios; Antipas, Georgios S. E.; Xenidis, Anthimos

    2016-01-01

    The thermodynamics, structural and transport properties (density, melting point, heat capacity, thermal expansion coefficient, viscosity and electrical conductivity) of a ferro-aluminosilicate slag have been studied in the solid and liquid state (1273–2273 K) using molecular dynamics. The simulations were based on a Buckingham-type potential, which was extended here, to account for the presence of Cr and Cu. The potential was optimized by fitting pair distribution function partials to values determined by Reverse Monte Carlo modelling of X-ray and neutron diffraction experiments. The resulting short range order features and ring statistics were in tight agreement with experimental data and created consensus for the accurate prediction of transport properties. Accordingly, calculations yielded rational values both for the average heat capacity, equal to 1668.58 J/(kg·K), and for the viscosity, in the range of 4.09–87.64 cP. The potential was consistent in predicting accurate values for mass density (i.e. 2961.50 kg/m3 vs. an experimental value of 2940 kg/m3) and for electrical conductivity (5.3–233 S/m within a temperature range of 1273.15–2273.15 K). PMID:27455915

  19. Chemical and physical transformations of aluminosilicate clay minerals due to acid treatment and consequences for heterogeneous ice nucleation.

    PubMed

    Sihvonen, Sarah K; Schill, Gregory P; Lyktey, Nicholas A; Veghte, Daniel P; Tolbert, Margaret A; Freedman, Miriam Arak

    2014-09-25

    Mineral dust aerosol is one of the largest contributors to global ice nuclei, but physical and chemical processing of dust during atmospheric transport can alter its ice nucleation activity. In particular, several recent studies have noted that sulfuric and nitric acids inhibit heterogeneous ice nucleation in the regime below liquid water saturation in aluminosilicate clay minerals. We have exposed kaolinite, KGa-1b and KGa-2, and montmorillonite, STx-1b and SWy-2, to aqueous sulfuric and nitric acid to determine the physical and chemical changes that are responsible for the observed deactivation. To characterize the changes to the samples upon acid treatment, we use X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy. We find that the reaction of kaolinite and montmorillonite with aqueous sulfuric acid results in the formation of hydrated aluminum sulfate. In addition, sulfuric and nitric acids induce large structural changes in montmorillonite. We additionally report the supersaturation with respect to ice required for the onset of ice nucleation for these acid-treated species. On the basis of lattice spacing arguments, we explain how the chemical and physical changes observed upon acid treatment could lead to the observed reduction in ice nucleation activity.

  20. Leaching of vanadium, sodium, and silicon from molten V-Ti-bearing slag obtained from low-grade vanadium-bearing titanomagnetite

    NASA Astrophysics Data System (ADS)

    Zhu, Yuan-yuan; Yi, Ling-yun; Zhao, Wei; Chen, De-sheng; Zhao, Hong-xin; Qi, Tao

    2016-08-01

    The water leaching process of vanadium, sodium, and silicon from molten vanadium-titanium-bearing (V-Ti-bearing) slag obtained from low-grade vanadium-bearing titanomagnetite was investigated systematically. The results show that calcium titanate, sodium aluminosilicate, sodium oxide, silicon dioxide and sodium vanadate are the major components of the molten V-Ti-bearing slag. The experimental results indicate that the liquid-solid (L/S) mass ratio significantly affects the leaching process because of the respective solubilities and diffusion rates of the components. A total of 83.8% of vanadium, 72.8% of sodium, and 16.1% of silicon can be leached out via a triple counter-current leaching process under the optimal conditions of a particle size below 0.074 mm, a temperature of 90°C, a leaching time of 20 min, an L/S mass ratio of 4:1, and a stirring speed of 300 r/min. The kinetics of vanadium leaching is well described by an internal diffusion-controlled model and the apparent activation energy is 11.1 kJ/mol. The leaching mechanism of vanadium was also analyzed.

  1. Action of insecticidal N-alkylamides at site 2 of the voltage-sensitive sodium channel

    SciTech Connect

    Ottea, J.A.; Payne, G.T.; Soderlund, D.M. )

    1990-08-01

    Nine synthetic N-alkylamides were examined as inhibitors of the specific binding of ({sup 3}H)batrachotoxinin A 20{alpha}-benzoate (({sup 3}H)BTX-B) to sodium channels and as activators of sodium uptake in mouse brain synaptoneurosomes. In the presence of scorpion (Leiurus quinquestriatus) venom, the six insecticidal analogues were active as both inhibitors of ({sup 3}H)BTX-B binding and stimulators of sodium uptake. These findings are consistent with an action of these compounds at the alkaloid activator recognition site (site 2) of the voltage-sensitive sodium channel. The three noninsecticidal N-alkylamides also inhibited ({sup 3}H)BTX-B binding but were ineffective as activators of sodium uptake. Concentration-response studies revealed that some of the insecticidal amides also enhanced sodium uptake through a second, high-affinity interaction that does not involve site 2, but this secondary effect does not appear to be correlated with insecticidal activity. The activities of N-alkylamides as sodium channel activators were influenced by the length of the alkenyl chain and the location of unsaturation within the molecule. These results further define the actions of N-alkylamides on sodium channels and illustrate the significance of the multiple binding domains of the sodium channel as target sites for insect control agents.

  2. A new titanium-bearing calcium aluminosilicate phase. 2: Crystallography and crystal chemistry of grains formed in slowly cooled melts with bulk compositions of calcium-aluminium-rich inclusions

    NASA Technical Reports Server (NTRS)

    Barber, David J.; Beckett, John R.; Paque, Julie M.; Stolper, Edward

    1994-01-01

    The crystallography and crystal chemistry of a new calcium- titanium-aluminosilicate mineral (UNK) observed in synthetic analogs to calcium-aluminum-rich inclusions (CAIs) from carbonaceous chondrites was studied by electron diffraction techniques. The unit cell is primitive hexagonal or trigonal, with a = 0.790 +/- 0.02 nm and c = 0.492 +/- 0.002 nm, similar to the lattice parameters of melilite and consistent with cell dimensions for crystals in a mixer furnace slag described by Barber and Agrell (1994). The phase frequently displays an epitactic relationship in which melilite acts as the host, with (0001)(sub UNK) parallel (001)(sub mel) and zone axis group 1 0 -1 0(sub UNK) parallel zone axis group 1 0 0(sub mel). If one of the two space groups determined by Barber and Agrell (1994) for their sample of UNK is applicable (P3m1 or P31m), then the structure is probably characterized by puckered sheets of octahedra and tetrahedra perpendicular to the c-axis with successive sheets coordinated by planar arrays of Ca. In this likely structure, each unit cell contains three Ca sites located in mirror planes, one octahedrally coordinated cation located along a three-fold axis and five tetrahedrally coordinated cations, three in mirrors and two along triads. The octahedron contains Ti but, because there are 1.3-1.9 cations of Ti/formula unit, some of the Ti must also be in tetrahedral coordination, an unusual but not unprecedented situation for a silicate. Tetrahedral sites in mirror planes would contain mostly Si, with lesser amounts of Al while those along the triads correspondingly contain mostly Al with subordinate Ti. The structural formula, therefore, can be expressed as Ca(sub 3)(sup VIII)(Ti,Al)(sup VI)(Al,Ti,Si)(sub 2)(sup IV)(Si,Al)(sub 3)(sup IV)O14 with Si + Ti = 4. Compositions of meteoritic and synthetic Ti-bearing samples of the phase can be described in terms of a binary solid solution between the end-members Ca3TiAl2Si3O14 and Ca3Ti(AlTi)(AlSi2)O14. A Ti

  3. An enantioselective formal synthesis of montelukast sodium.

    PubMed

    Bollikonda, Satyanarayana; Mohanarangam, Saravanan; Jinna, Rajender Reddy; Kandirelli, Venkata Kiran Kumar; Makthala, Laxman; Sen, Saikat; Chaplin, David A; Lloyd, Richard C; Mahoney, Thomas; Dahanukar, Vilas Hareshwar; Oruganti, Srinivas; Fox, Martin E

    2015-04-17

    A formal synthesis of the antiasthma drug montelukast sodium is described, wherein the key chiral diol intermediate was accessed with greater convergence of the C-C bond-forming steps as compared to previous routes. Improved synthetic efficiency was achieved by deploying homogeneous metal-based catalysis in two pivotal steps. In the first, a tandem Mizoroki-Heck reaction and double-bond isomerization between a previously known allyl alcohol intermediate and a hindered 2-(2-halophenyl)propan-2-ol secured direct access to the 3-(2-(2-hydroxypropan-2-yl)phenyl)-1-phenylpropan-1-one moiety in the product. In the second step, asymmetric hydrogenation of the ketone functionality in the Mizoroki-Heck reaction product provided a convenient method to introduce the benzylic alcohol chiral center and obtain the desired chiral diol precursor of montelukast sodium. A detailed catalyst screening led to the identification of ((R)-Xyl-BINAP)((R,R)-DPEN)RuCl2 as a catalyst that afforded an enantioselectivity of 99% ee in the hydrogenation step on a multigram lab scale at a molar substrate:catalyst loading of 5000:1. PMID:25807000

  4. Approaches to chemical synthetic biology.

    PubMed

    Chiarabelli, Cristiano; Stano, Pasquale; Anella, Fabrizio; Carrara, Paolo; Luisi, Pier Luigi

    2012-07-16

    Synthetic biology is first represented in terms of two complementary aspects, the bio-engineering one, based on the genetic manipulation of extant microbial forms in order to obtain forms of life which do not exist in nature; and the chemical synthetic biology, an approach mostly based on chemical manipulation for the laboratory synthesis of biological structures that do not exist in nature. The paper is mostly devoted to shortly review chemical synthetic biology projects currently carried out in our laboratory. In particular, we describe: the minimal cell project, then the "Never Born Proteins" and lastly the Never Born RNAs. We describe and critically analyze the main results, emphasizing the possible relevance of chemical synthetic biology for the progress in basic science and biotechnology.

  5. Is synthetic biology mechanical biology?

    PubMed

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  6. Synthetic Biology for Specialty Chemicals.

    PubMed

    Markham, Kelly A; Alper, Hal S

    2015-01-01

    In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

  7. Synthetic Turf Multiplies Stadium Use.

    ERIC Educational Resources Information Center

    Leach, Richard

    1979-01-01

    The high school stadium in Flint, Michigan, once was used only for varsity football games. After the installation of synthetic turf, an average of 332 events have been staged there each year. (Author/MLF)

  8. Programming languages for synthetic biology.

    PubMed

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented. PMID:22132053

  9. Programming languages for synthetic biology.

    PubMed

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented.

  10. SYNTHETIC SLING FAILURE - EVALUATIONS & RECOMMENDATIONS

    SciTech Connect

    MACKEY TC; HENDERSON CS

    2009-10-26

    The information and evaluations provided in this report were compiled to address the recurring problem of synthetic sling failure. As safety is the number one priority in all work aspects, a solution must be devised to prevent accidents from occurring. A total of thirteen cases regarding synthetic sling failure were evaluated in order to determine their causes, effects, and preventative measures. From the collected data, it was found that all cases in which the synthetic sling contacted the edge of its load resulted in sling failure. It is required that adequate synthetic sling protection devices be used to protect slings in any lift where the sling comes in direct contact with the edge or corner of its load. However, there are no consensus codes or standards stating the type, material, or purpose of the type of protective device used to protect the sling from being cut. Numerous industry standards and codes provide vague descriptions on how to protect synthetic slings. Without a clear, concise statement of how to protect synthetic slings, it is common for inadequate materials and sling protection devices to be used in an attempt to meet the intent of these requirements. The use of an inadequate sling protection device is the main cause of synthetic sling failure in all researched cases. Commercial sling protection devices come in many shapes and sizes, and have a variety of names, as well as advertised uses. 'Abrasion pads' and 'wear protectors' are two different names for products with the same intended purpose. There is no distinguishable way to determine the extent of sling protection which these devices will provide, or what specific scenarios they are made for. This creates room for error in a field where error is unacceptable. This report provides a recommended action for hoisting and rigging activities which require synthetic slings to contact a load, as well as recommended changes to industry standards which will benefit overall industry safety.

  11. Compounding in synthetic aperture imaging.

    PubMed

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-09-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution and clutter levels are measured using a wire phantom setup and compared with conventional application of the array, as well as to synthetic aperture imaging without compounding. If the full aperture is used for synthetic aperture compounding, the cystic resolution is improved by 41% compared with conventional imaging, and is at least as good as what can be obtained using synthetic aperture imaging without compounding. PMID:23007781

  12. Superresolution and Synthetic Aperture Radar

    SciTech Connect

    DICKEY,FRED M.; ROMERO,LOUIS; DOERRY,ARMIN W.

    2001-05-01

    Superresolution concepts offer the potential of resolution beyond the classical limit. This great promise has not generally been realized. In this study we investigate the potential application of superresolution concepts to synthetic aperture radar. The analytical basis for superresolution theory is discussed. The application of the concept to synthetic aperture radar is investigated as an operator inversion problem. Generally, the operator inversion problem is ill posed. A criterion for judging superresolution processing of an image is presented.

  13. Solid-State NMR Identification and Quantification of Newly Formed Aluminosilicate Phases in Weathered Kaolinite Systems

    SciTech Connect

    Crosson, Garry S.; Choi, Sunkyung; Chorover, Jon; Amistadi, Mary K.; O'Day, Peggy A.; Mueller, Karl T.

    2006-01-19

    The weathering of a specimen kaolinite clay was studied over the course of 369 d via solid-state 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and high-field 27Al MAS NMR. The chosen baseline solution conditions (0.05 mol kg-1 of Al, 2 mol kg-1 of Na+, 1 mol kg-1 of NO3 -, 1 mol kg-1 of OH-, and pH ~13.8) approximate those of solutions leaking from waste tanks at the Hanford Site in Richland, WA. Nonradioactive Cs and Sr cations were added to this synthetic tank waste leachate (STWL) solution at concentrations of 10-3, 10-4, and 10-5 molal (m) to represent their radionuclide counterparts. The transformations of silicon- and aluminum-containing solid phase species were monitored quantitatively by using NMR spectroscopy, with the resulting spectra directly reporting the influence of the initial Cs and Sr on formation and transformation of the neo-formed solids. At the lowest concentration of Cs and Sr employed (10-5 m in each cation) peaks consistent with the formation of zeolite-like minerals were detected via 29Si and 27Al MAS NMR as early as 33 d. At concentrations of 10-3 m in each cation, new silicon species are not detected until 93 d, although neophases containing four-coordinate aluminum were detectable at earlier reaction times via 27Al MAS NMR. At the highest magnetic field strengths employed in this NMR study, deconvolutions of resonances detected in the tetrahedral region of the 27Al MAS spectra yielded multiple components, indicating the existence of at least four new aluminum-containing phases. Two of these phases are identified as sodalite and cancrinite through comparison with diffuse-reflectance infrared (DRIFT) spectra and powder X-ray diffraction (XRD) results, while a third phase may correlate with a previously detected aluminum-rich chabazite phase. All measurable solid reaction products have been quantified via their 27Al MAS resonances acquired at high magnetic field strengths (17.6 T), and the quantitative

  14. Bioinspired Artificial Sodium and Potassium Ion Channels.

    PubMed

    Rodríguez-Vázquez, Nuria; Fuertes, Alberto; Amorín, Manuel; Granja, Juan R

    2016-01-01

    In Nature, all biological systems present a high level of compartmentalization in order to carry out a wide variety of functions in a very specific way. Hence, they need ways to be connected with the environment for communication, homeostasis equilibrium, nutrition, waste elimination, etc. The biological membranes carry out these functions; they consist of physical insulating barriers constituted mainly by phospholipids. These amphipathic molecules spontaneously aggregate in water to form bilayers in which the polar groups are exposed to the aqueous media while the non-polar chains self-organize by aggregating to each other to stay away from the aqueous media. The insulating properties of membranes are due to the formation of a hydrophobic bilayer covered at both sides by the hydrophilic phosphate groups. Thus, lipophilic molecules can permeate the membrane freely, while the small charged or very hydrophilic molecules require the assistance of other membrane components in order to overcome the energetic cost implied in crossing the non-polar region of the bilayer. Most of the large polar species (such as oligosaccharides, polypeptides or nucleic acids) cross into and out of the cell via endocytosis and exocytosis, respectively. Nature has created a series of systems (carriers and pores) in order to control the balance of small hydrophilic molecules and ions. The most important structures to achieve these goals are the ionophoric proteins that include the channel proteins, such as the sodium and potassium channels, and ionic transporters, including the sodium/potassium pumps or calcium/sodium exchangers among others. Inspired by these, scientists have created non-natural synthetic transporting structures to mimic the natural systems. The progress in the last years has been remarkable regarding the efficient transport of Na(+) and K(+) ions, despite the fact that the selectivity and the ON/OFF state of the non-natural systems remain a present and future challenge

  15. Bioinspired Artificial Sodium and Potassium Ion Channels.

    PubMed

    Rodríguez-Vázquez, Nuria; Fuertes, Alberto; Amorín, Manuel; Granja, Juan R

    2016-01-01

    In Nature, all biological systems present a high level of compartmentalization in order to carry out a wide variety of functions in a very specific way. Hence, they need ways to be connected with the environment for communication, homeostasis equilibrium, nutrition, waste elimination, etc. The biological membranes carry out these functions; they consist of physical insulating barriers constituted mainly by phospholipids. These amphipathic molecules spontaneously aggregate in water to form bilayers in which the polar groups are exposed to the aqueous media while the non-polar chains self-organize by aggregating to each other to stay away from the aqueous media. The insulating properties of membranes are due to the formation of a hydrophobic bilayer covered at both sides by the hydrophilic phosphate groups. Thus, lipophilic molecules can permeate the membrane freely, while the small charged or very hydrophilic molecules require the assistance of other membrane components in order to overcome the energetic cost implied in crossing the non-polar region of the bilayer. Most of the large polar species (such as oligosaccharides, polypeptides or nucleic acids) cross into and out of the cell via endocytosis and exocytosis, respectively. Nature has created a series of systems (carriers and pores) in order to control the balance of small hydrophilic molecules and ions. The most important structures to achieve these goals are the ionophoric proteins that include the channel proteins, such as the sodium and potassium channels, and ionic transporters, including the sodium/potassium pumps or calcium/sodium exchangers among others. Inspired by these, scientists have created non-natural synthetic transporting structures to mimic the natural systems. The progress in the last years has been remarkable regarding the efficient transport of Na(+) and K(+) ions, despite the fact that the selectivity and the ON/OFF state of the non-natural systems remain a present and future challenge.

  16. Synthetic biology as red herring.

    PubMed

    Preston, Beth

    2013-12-01

    It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy.

  17. Sodium channels and pain.

    PubMed

    Habib, Abdella M; Wood, John N; Cox, James J

    2015-01-01

    Human and mouse genetic studies have led to significant advances in our understanding of the role of voltage-gated sodium channels in pain pathways. In this chapter, we focus on Nav1.7, Nav1.8, Nav1.9 and Nav1.3 and describe the insights gained from the detailed analyses of global and conditional transgenic Nav knockout mice in terms of pain behaviour. The spectrum of human disorders caused by mutations in these channels is also outlined, concluding with a summary of recent progress in the development of selective Nav1.7 inhibitors for the treatment of pain. PMID:25846613

  18. Magnetometry with mesospheric sodium

    PubMed Central

    Higbie, James M.; Rochester, Simon M.; Patton, Brian; Holzlöhner, Ronald; Bonaccini Calia, Domenico; Budker, Dmitry

    2011-01-01

    Measurement of magnetic fields on the few 100-km length scale is significant for many geophysical applications including mapping of crustal magnetism and ocean circulation measurements, yet available techniques for such measurements are very expensive or of limited accuracy. We propose a method for remote detection of magnetic fields using the naturally occurring atomic sodium-rich layer in the mesosphere and existing high-power lasers developed for laser guide star applications. The proposed method offers a dramatic reduction in cost and opens the way to large-scale, parallel magnetic mapping and monitoring for atmospheric science, navigation, and geophysics. PMID:21321235

  19. Synthetic Eelgrass Oil Barrier

    NASA Astrophysics Data System (ADS)

    Curtis, T. G.

    2013-05-01

    Although surviving in situ micro-organisms eventually consume spilled oil, extensive inundation of shore biota by oil requires cleanup to enable ecological recovery within normal time scales. Although effective in calm seas and quiet waters, oil is advected over and under conventional curtain oil booms by wave actions and currents when seas are running. Most sorbent booms are not reusable, and are usually disposed of in landfills, creating excessive waste. A new concept is proposed for a floating oil barrier, to be positioned off vulnerable coasts, to interdict, contain, and sequester spilled oil, which can then be recovered and the barrier reused. While conventional oil boom designs rely principally on the immiscibility of oil in water and its relative buoyancy, the new concept barrier avoids the pitfalls of the former by taking advantage of the synergistic benefits of numerous fluid and material properties, including: density, buoyancy, elasticity, polarity, and surface area to volume ratio. Modeled after Zostera marina, commonly called eelgrass, the new barrier, referred to as synthetic eelgrass (SE), behaves analogously. Eelgrass has very long narrow, ribbon-like, leaves which support periphyton, a complex matrix of algae and heterotrophic microbes, which position themselves there to extract nutrients from the seawater flowing past them. In an analogous fashion, oil on, or in, seawater, which comes in contact with SE, is adsorbed on the surface and sequestered there. Secured to the bottom, in shoal waters, SE rises to the surface, and, if the tide is low enough, floats on the sea surface down wind, or down current to snare floating oil. The leaves of SE, called filaments, consist of intrinsically buoyant strips of ethylene methyl acrylate, aka EMA. EMA, made of long chain, saturated, hydrocarbon molecules with nearly homogeneous electron charge distributions, is a non-polar material which is oleophilic and hydrophobic. Oil must be in close proximity to the

  20. Sodium bicarbonate in chemical flooding: Part 1: Topical report. [Sodium bicarbonate and sodium carbonate

    SciTech Connect

    Peru, D.A.; Lorenz, P.B.

    1987-07-01

    To compare oil recovery and alkali consumption in alkaline flooding using sodium bicarbonate with other alkaline agents, coreflooding experiments were performed in turn with viscosified sodium bicarbonate and viscosified sodium carbonate solutions. Oil recovery was monitored, and the effluent brine from these corefloods was analyzed for silicon, aluminum, pH, and total inorganic carbon. The results indicate that viscosified sodium bicarbonate recovered more of the asphaltic Cerro-Negro crude than of the less asphaltic Wilmington crude oil. The recovery efficiency using the viscosified sodium carbonate was similar for the two crudes. For both crudes, the percent oil recovery using viscosified sodium carbonate was slightly higher than that using the viscosified sodium bicarbonate. Mineral dissolution and decrease in pH were found to be greater in corefloods using viscosified sodium carbonate. Total inorganic carbon recovery can be obtained in corefloods with either agent, provided that a sufficient water drive follows the chemical slug. Long-term experiments were performed by recirculating alkaline solutions through oil-free, unfired Berea sandstone to monitor the rock/alkali interactions. The experimental results indicate an eight-fold decrease in quartz dissolution by sodium bicarbonate compared with sodium carbonate. Moderate magnesium solubility was observed at the pH of the bicarbonate solution. Low solubility of magnesium and aluminum at the pH of the carbonate indicates the possible formation of precipitates. In these experiments 13% of the carbonate was converted to bicarbonate. Total alkalinity was not significantly decreased with either agent. 18 refs., 5 tabs.

  1. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    PubMed

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. PMID:26272997

  2. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    PubMed

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms.

  3. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project

    PubMed Central

    Sliva, Anna; Yang, Huanming; Boeke, Jef D.; Mathews, Debra J. H.

    2015-01-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) Project is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 Project: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. PMID:26272997

  4. Europa Sodium Cloud: orbital variability and Sodium recycling

    NASA Astrophysics Data System (ADS)

    Cipriani, F.; Leblanc, F.; Witasse, O.

    2007-08-01

    Discovery and further observations of Europa's thin atmosphere of sodium have been carried out by M.E. Brown (Brown and Hill 1996, Brown 2001, Brown 2004) and A.E. Potter and co-workers (Leblanc et al, 2005). The resonant scattering emission of sodium around Europa has been successfully modelled and compared to the compilation of such observations by Leblanc at al 2002; Leblanc et al 2005). Such an analysis confirmed that the cloud morphology is dominated by the production of Na from the trailing hemisphere. The influence of Europa's centrifugal latitude as well as the contribution of Io's sodium source at Europa orbit were also estimated. These studies concluded that the observed sodium atmosphere should be largely endogenic to Europa. However, significant variations of the total emission intensity along Europa's orbit around Jupiter were reported that were difficult to explain without adhoc assumptions on the variability of the sodium ejecta rate with respect to Europa position in Jupiter magnetosphere. In the present study, we investigate the redistribution of the ejected sodium atoms on the surface of the moon during its orbit around Jupiter following the suggestion by Leblanc et al (2005). In our model, the redistribution of sodium atoms at Europa's surface occurs from a set of ejection and absorption of the sodium atoms. Ejection processes are sputtering induced by energetic jovian particles, as well as photo-stimulated and thermal desorptions from the surface. Absorption mainly depends on the surface temperature and porosity. We will present comparisons of the newly calculated sodium emission with the observations, as well as density distributions of sodium at Europa's surface. Consequences of those calculations on the sodium cloud morphology will also be discussed.

  5. Effects of synthetic conditions on the textural structure of pseudo-boehmite.

    PubMed

    Yang, Yang; Xu, Yanyan; Han, Baozhai; Xu, Benjing; Liu, Xinmei; Yan, Zifeng

    2016-05-01

    Mesoporous alumina with pseudo-boehmite phase was prepared by using the cation-anion double hydrolysis method from mixed aqueous solution of aluminum sulfate and sodium aluminate. The effect of synthetic conditions on the crystal structure and textual properties of pseudo-boehmite was investigated, such as synthetic temperature, pH value and the addition of sodium silicate. With the assistance of characterization techniques, such as X-ray diffraction (XRD), N2 adsorption-desorption isotherms (BET) and (27)Al magic-angle spinning nuclear magnetic resonance (MAS NMR), the relationship between textural properties of the mesoporous alumina samples and their synthetic conditions was discussed. The results displayed that an increase in synthesis temperature promoted the formation of higher crystalline pseudo-boehmite with the increase of its surface area and pore volume. Pure pseudo-boehmite phase could be obtained in the pH value range from 6.0 to 9.0, while bayerite phase occurred when the pH value was over 10.0. The introduction of sodium silicate could greatly improve the pore volume (1.20 cm(3)/g) and surface area (480.2 m(2)/g) of pseudo-boehmite. Interestingly, pure pseudo-boehmite phase was obtained at very high pH value without formation of bayerite phase when sodium silicate was initially added into the aluminum hydroxide colloid.

  6. A Simple Quantitative Synthesis: Sodium Chloride from Sodium Carbonate.

    ERIC Educational Resources Information Center

    Gold, Marvin

    1988-01-01

    Describes a simple laboratory procedure for changing sodium carbonate into sodium chloride by adding concentrated HCl to cause the reaction and then evaporating the water. Claims a good stoichiometric yield can be obtained in one three-hour lab period. Suggests using fume hood for the reaction. (ML)

  7. GENOTOXICITY STUDIES OF SODIUM DICHLOROACETATE AND SODIUM TRICHLOROACETATE

    EPA Science Inventory

    The genotoxic properties of sodium dichloroacetate (DCA) and sodium trichloroacetate (TCA)were evaluated in several short-term in vitro and in vivo assays. Neither compound was mutagenic in tester strain TA102 in the Salmonella mutagenicity assay. Both DCA and TCA were weak induc...

  8. Detecting Nanophase Weathering Products with CheMin: Reference Intensity Ratios of Allophane, Aluminosilicate Gel, and Ferrihydrite

    NASA Technical Reports Server (NTRS)

    Rampe, E. B.; Bish, D. L.; Chipera, S. J.; Morris, R. V.; Achilles, C. N.; Ming, D W.; Blake, D. F.; Anderson, R. C.; Bristow, T. F.; Crisp, A.; DesMarais, D. J.; Downs, R. T.; Farmer, J. D.; Morookian, J. M.; Morrison, S. M.; Sarrazin, P.; Spanovich, N.; Stolper, E. M.; Treiman, A. H.; Vaniman, D. T.; Yen, A. S.

    2013-01-01

    X-ray diffraction (XRD) data collected of the Rocknest samples by the CheMin instrument on Mars Science Laboratory suggest the presence of poorly crystalline or amorphous materials [1], such as nanophase weathering products or volcanic and impact glasses. The identification of the type(s) of X-ray amorphous material at Rocknest is important because it can elucidate past aqueous weathering processes. The presence of volcanic and impact glasses would indicate that little chemical weathering has occurred because glass is highly susceptible to aqueous alteration. The presence of nanophase weathering products, such as allophane, nanophase iron-oxides, and/or palagonite, would indicate incipient chemical weathering. Furthermore, the types of weathering products present could help constrain pH conditions and identify which primary phases altered to form the weathering products. Quantitative analysis of phases from CheMin data is achieved through Reference Intensity Ratios (RIRs) and Rietveld refinement. The RIR of a mineral (or mineraloid) that relates the scattering power of that mineral (typically the most intense diffraction line) to the scattering power of a separate mineral standard such as corundum [2]. RIRs can be calculated from XRD patterns measured in the laboratory by mixing a mineral with a standard in known abundances and comparing diffraction line intensities of the mineral to the standard. X-ray amorphous phases (e.g., nanophase weathering products) have broad scattering signatures rather than sharp diffraction lines. Thus, RIRs of X-ray amorphous materials are calculated by comparing the area under one of these broad scattering signals with the area under a diffraction line in the standard. Here, we measured XRD patterns of nanophase weathering products (allophane, aluminosilicate gel, and ferrihydrite) mixed with a mineral standard (beryl) in the CheMinIV laboratory instrument and calculated their RIRs to help constrain the abundances of these phases in

  9. Evidence of energy transfer in an aluminosilicate glass codoped with Si nanoaggregates and Er{sup 3+} ions

    SciTech Connect

    Enrichi, F.; Mattei, G.; Sada, C.; Trave, E.; Pacifici, D.; Franzo, G.; Priolo, F.; Iacona, F.; Prassas, M.; Falconieri, M.; Borsella, E.

    2004-10-01

    The enhancement of the Er{sup 3+} ions' photoluminescence (PL) emission at 1.54 {mu}m in a Si and Er coimplanted aluminosilicate glass is investigated in detail. A postimplantation thermal treatment has been performed to recover the damage induced by the implantation process and to promote Si aggregation. It will be shown that 1 h treatment in N{sub 2} atmosphere is not sufficient to induce Si precipitation for temperatures up to 500 deg. C. Nevertheless, the most intense Er{sup 3+} PL emission at 1.54 {mu}m is achieved after a thermal treatment at 400 deg. C. Such emission has been investigated by pumping in and out of resonance, showing a very efficient energy transfer process in the whole excitation wavelength range (360-515 nm). These results suggest that good energy transfer mediators could be small Si aggregates and not only crystalline clusters. For the best performing sample, the effective Er excitation cross section has been measured to be higher than 10{sup -17} cm{sup 2} at 379 and 390 nm and about 2x10{sup -16} cm{sup 2} at 476 nm, that is, several orders of magnitude higher than the Er direct absorption cross section (of the order of 10{sup -21} cm{sup 2} in this glass). Moreover the coefficient of cooperative upconversion has been evaluated to be 2.7x10{sup -18} cm{sup 3} s{sup -1}. The structural and optical properties of this material are discussed and compared to those found for Si and Er codoped silica.

  10. Final report on the safety assessment of Sodium Metaphosphate, Sodium Trimetaphosphate, and Sodium Hexametaphosphate.

    PubMed

    Lanigan, R S

    2001-01-01

    These inorganic polyphosphate salts all function as chelating agents in cosmetic formulations. In addition, Sodium Metaphosphate functions as an oral care agent, Sodium Trimetaphosphate as a buffering agent, and Sodium Hexametaphosphate as a corrosion inhibitor. Only Sodium Hexametaphosphate is currently reported to be used. Although the typical concentrations historically have been less than 1%, higher concentrations have been used in products such as bath oils, which are diluted during normal use. Sodium Metaphosphate is the general term for any polyphosphate salt with four or more phosphate units. The four-phosphate unit version is cyclic, others are straight chains. The hexametaphosphate is the specific six-chain length form. The trimetaphosphate structure is cyclic. Rats fed 10% Sodium Trimetaphosphate for a month exhibited transient tubular necrosis; rats given 10% Sodium Metaphosphate had retarded growth and those fed 10% Sodium Hexametaphosphate had pale and swollen kidneys. In chronic studies using animals, growth inhibition, increased kidney weights (with calcium deposition and desquamation), bone decalcification, parathyroid hypertrophy and hyperplasia, inorganic phosphaturia, hepatic focal necrosis, and muscle fiber size alterations. Sodium Hexametaphosphate was a severe skin irritant in rabbits, whereas a 0.2% solution was only mildly irritating. A similar pattern was seen with ocular toxicity. These ingredients were not genotoxic in bacterial systems nor were they carcinogenic in rats. No reproductive or developmental toxicity was seen in studies using rats exposed to Sodium Hexametaphosphate or Sodium Trimetaphosphate. In clinical testing, irritation is seen as a function of concentration; concentrations as high as 1% produced no irritation in contact allergy patients. Because of the corrosive nature of Sodium Hexametaphosphate, it was concluded that these ingredients could be used safely if each formulation was prepared to avoid skin irritation; for

  11. Control theory meets synthetic biology.

    PubMed

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. PMID:27440256

  12. Control theory meets synthetic biology.

    PubMed

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology.

  13. Control theory meets synthetic biology

    PubMed Central

    2016-01-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. PMID:27440256

  14. Content metamorphosis in synthetic holography

    NASA Astrophysics Data System (ADS)

    Desbiens, Jacques

    2013-02-01

    A synthetic hologram is an optical system made of hundreds of images amalgamated in a structure of holographic cells. Each of these images represents a point of view on a three-dimensional space which makes us consider synthetic holography as a multiple points of view perspective system. In the composition of a computer graphics scene for a synthetic hologram, the field of view of the holographic image can be divided into several viewing zones. We can attribute these divisions to any object or image feature independently and operate different transformations on image content. In computer generated holography, we tend to consider content variations as a continuous animation much like a short movie. However, by composing sequential variations of image features in relation with spatial divisions, we can build new narrative forms distinct from linear cinematographic narration. When observers move freely and change their viewing positions, they travel from one field of view division to another. In synthetic holography, metamorphoses of image content are within the observer's path. In all imaging Medias, the transformation of image features in synchronisation with the observer's position is a rare occurrence. However, this is a predominant characteristic of synthetic holography. This paper describes some of my experimental works in the development of metamorphic holographic images.

  15. Meeting Report: Synthetic Biology Jamboree for Undergraduates

    ERIC Educational Resources Information Center

    Campbell, A. Malcolm

    2005-01-01

    The field of synthetic biology (the name is derived from an analogy to synthetic chemistry) has recognized itself as a "field" only since about 2002. Synthetic biology has gotten some high-profile attention recently, but most people are not aware the field even exists. Synthetic biologists apply engineering principles to genomic circuits to…

  16. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium alginate. 184.1724 Section 184.1724 Food... GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate is prepared by...

  17. 21 CFR 184.1724 - Sodium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium alginate. 184.1724 Section 184.1724 Food and... Substances Affirmed as GRAS § 184.1724 Sodium alginate. (a) Sodium alginate (CAS Reg. No. 9005-38-3) is the sodium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Sodium alginate...

  18. 21 CFR 186.1756 - Sodium formate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1756 Sodium formate. (a) Sodium formate (CHNaO2, CAS Reg. No. 141-53-7) is the sodium salt of formic acid. It is produced by the reaction of carbon monoxide with sodium hydroxide. (b) The ingredient is... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium formate. 186.1756 Section 186.1756 Food...

  19. 21 CFR 201.64 - Sodium labeling.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... contains sodium bicarbonate, sodium phosphate, or sodium biphosphate as an active ingredient for oral... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Sodium labeling. 201.64 Section 201.64 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.64 Sodium labeling. (a) The labeling...

  20. 21 CFR 184.1733 - Sodium benzoate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Specific Substances Affirmed as GRAS § 184.1733 Sodium benzoate. (a) Sodium benzoate is the chemical benzoate of soda (C7H5NaO2), produced by the neutralization of benzoic acid with sodium bicarbonate, sodium... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium benzoate. 184.1733 Section 184.1733...