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Sample records for les sols agricoles

  1. Comparison des donnees simulees des capteurs de SPOT et landsat-D: Application a une region agricole

    NASA Astrophysics Data System (ADS)

    Saint, Gilbert; Podaire, Alain

    La modélisation de la luminance spectrale des objets observés en télédétection permet d'effectuer des simulations de différents capteurs à partir de données obtenues au moyen d'un scanneur DAEDALUS aéroporté : les qualités radiométrique et géométrique ont pu être évaluées par une comparaison avec des données Landsat réelles. L'analyse sur une zone agricole met surtout en évidence le rôle important de l'accroissement de la résolution.

  2. Telltale Animation (Sol 9)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This animation of the NASA's Phoenix Mars Lander's telltale was made from five images taken by Phoenix's Stereo Surface Imager (SSI) near 3:00 PM local Mars time on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). The images were taken with a blue filter (450 nanometer, R6) that focuses at items on the deck rather than the workspace or horizon.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  3. Telltale Animation (Sol 8)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This animation of the NASA's Phoenix Mars Lander's telltale was made from five images taken by Phoenix's Stereo Surface Imager (SSI) just after 1:10 PM local Mars time on the eighth Martian day of the mission, or Sol 8 (June 2, 2008). The images were taken with a blue filter (450 nanometer, R6) that focuses at items on the deck rather than the workspace or horizon.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. Telltale Animation (Sol 9)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This animation of the NASA's Phoenix Mars Lander's telltale was made from five images taken by Phoenix's Stereo Surface Imager (SSI) just after 4:37 PM local Mars time on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). The images were taken with a blue filter (450 nanometer, R6) that focuses at items on the deck rather than the workspace or horizon.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Petruska, Melissa A.; Klimov, Victor L.

    2012-06-12

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites

  6. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Petruska, Melissa A.; Klimov, Victor L.

    2007-06-05

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites.

  7. Les jeux de hasard chez les enfants et les adolescents

    PubMed Central

    Gupta, Rina; Pinzon, Jorge L

    2012-01-01

    RÉSUMÉ Même si, au Canada, les mineurs n’ont pas le droit de jouer à des jeux de hasard légalisés, les adolescents participent souvent à des jeux de hasard soit légalisés (produits de loterie, casino, terminaux de jeux vidéo), soit autonomes (jeux de cartes, paris sportifs, dés) à la maison et en milieu scolaire. Chez les adultes, le taux de prévalence de dépendance aux jeux de hasard au cours de la vie se situe entre 1 % et 2 %. D’après les données existantes, la prévalence chez les adolescents serait de deux à quatre fois plus élevée. On ne sait pas grand-chose des facteurs de risque d’apparition et de perpétuation d’une dépendance pathologique aux jeux de hasard. Le présent document de principes vise à informer les pédiatres, les médecins de famille et les autres professionnels de la santé des connaissances émergentes sur les jeux de hasard pendant l’enfance et l’adolescence et du risque de conséquences graves qui s’y rattachent. On y exhorte également les gouvernements fédéral, provinciaux et territoriaux à inclure cette question dans leur programme et à tenir compte des facteurs sociopolitiques associés aux jeux de hasard.

  8. Sol-gel derived sorbents

    DOEpatents

    Sigman, Michael E.; Dindal, Amy B.

    2003-11-11

    Described is a method for producing copolymerized sol-gel derived sorbent particles for the production of copolymerized sol-gel derived sorbent material. The method for producing copolymerized sol-gel derived sorbent particles comprises adding a basic solution to an aqueous metal alkoxide mixture for a pH.ltoreq.8 to hydrolyze the metal alkoxides. Then, allowing the mixture to react at room temperature for a precalculated period of time for the mixture to undergo an increased in viscosity to obtain a desired pore size and surface area. The copolymerized mixture is then added to an immiscible, nonpolar solvent that has been heated to a sufficient temperature wherein the copolymerized mixture forms a solid upon the addition. The solid is recovered from the mixture, and is ready for use in an active sampling trap or activated for use in a passive sampling trap.

  9. Opportunity's Surroundings on Sol 1687

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008).

    Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction.

    Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast.

    This view is presented as a cylindrical projection with geometric seam correction.

  10. Opportunity's Surroundings on Sol 1818

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends.

    The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view.

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical projection with geometric seam correction.

  11. Sol-Gel Derived Hafnia Coatings

    NASA Technical Reports Server (NTRS)

    Feldman, Jay D.; Stackpoole, Mairead; Blum, Yigal; Sacks, Michael; Ellerby, Don; Johnson, Sylvia M.; Venkatapathy, Ethiras (Technical Monitor)

    2002-01-01

    Sol-gel derived hafnia coatings are being developed to provide an oxidation protection layer on ultra-high temperature ceramics for potential use in turbine engines (ultra-efficient engine technology being developed by NASA). Coatings using hafnia sol hafnia filler particles will be discussed along with sol synthesis and characterization.

  12. SOL Tests Create Unfair Pressure.

    ERIC Educational Resources Information Center

    Ernst, Katie

    2000-01-01

    A seventh-grader explains why the Virginia Standards of Learning tests unfairly pressure her and her teachers. She wants her free reading time restored and wishes politicians would worry more about students understanding--not just memorizing--facts. She praises teachers who go beyond the SOL. (MLH)

  13. The SOL: No Easy Answers.

    ERIC Educational Resources Information Center

    Pasi, Raymond

    2000-01-01

    Since the state board adopted the Standards of Learning, Virginia high-school teachers maintain tighter schedules and more often use direct instruction instead of group activities to cover the new curriculum. A two-edged sword, the SOL has engendered an increased interest in professional collaboration. (MLH)

  14. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Klimov, Victor L.; Petruska, Melissa A.

    2010-05-25

    The present invention is directed to a process for preparing a solid composite having colloidal nanocrystals dispersed within a sol-gel matrix, the process including admixing colloidal nanocrystals with an amphiphilic polymer including hydrophilic groups selected from the group consisting of --COOH, --OH, --SO.sub.3H, --NH.sub.2, and --PO.sub.3H.sub.2 within a solvent to form an alcohol-soluble colloidal nanocrystal-polymer complex, admixing the alcohol-soluble colloidal nanocrystal-polymer complex and a sol-gel precursor material, and, forming the solid composite from the admixture. The present invention is also directed to the resultant solid composites and to the alcohol-soluble colloidal nanocrystal-polymer complexes.

  15. Opportunity's Surroundings on Sol 1798

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top.

    The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical projection with geometric seam correction.

  16. Metal-silica sol-gel materials

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E. (Inventor)

    2002-01-01

    The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

  17. Hybrid sol-gel optical materials

    DOEpatents

    Zeigler, J.M.

    1993-04-20

    Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

  18. Hybrid sol-gel optical materials

    DOEpatents

    Zeigler, John M.

    1993-01-01

    Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

  19. Hybrid sol-gel optical materials

    DOEpatents

    Zeigler, John M.

    1992-01-01

    Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

  20. SOL - SIZING AND OPTIMIZATION LANGUAGE COMPILER

    NASA Technical Reports Server (NTRS)

    Scotti, S. J.

    1994-01-01

    SOL is a computer language which is geared to solving design problems. SOL includes the mathematical modeling and logical capabilities of a computer language like FORTRAN but also includes the additional power of non-linear mathematical programming methods (i.e. numerical optimization) at the language level (as opposed to the subroutine level). The language-level use of optimization has several advantages over the traditional, subroutine-calling method of using an optimizer: first, the optimization problem is described in a concise and clear manner which closely parallels the mathematical description of optimization; second, a seamless interface is automatically established between the optimizer subroutines and the mathematical model of the system being optimized; third, the results of an optimization (objective, design variables, constraints, termination criteria, and some or all of the optimization history) are output in a form directly related to the optimization description; and finally, automatic error checking and recovery from an ill-defined system model or optimization description is facilitated by the language-level specification of the optimization problem. Thus, SOL enables rapid generation of models and solutions for optimum design problems with greater confidence that the problem is posed correctly. The SOL compiler takes SOL-language statements and generates the equivalent FORTRAN code and system calls. Because of this approach, the modeling capabilities of SOL are extended by the ability to incorporate existing FORTRAN code into a SOL program. In addition, SOL has a powerful MACRO capability. The MACRO capability of the SOL compiler effectively gives the user the ability to extend the SOL language and can be used to develop easy-to-use shorthand methods of generating complex models and solution strategies. The SOL compiler provides syntactic and semantic error-checking, error recovery, and detailed reports containing cross-references to show where

  1. Opportunity's View, Sol 958 (Stereo)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA01897

    [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA01897

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo view of the rover's surroundings on the 958th sol, or Martian day, of its surface mission (Oct. 4, 2006).

    This view is presented as a cylindrical-perspective projection with geometric seam correction. The image appears three-dimensional when viewed through red-green stereo glasses.

  2. Opportunity's View, Sol 959, (Stereo)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA01893

    [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA01893

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo view of the rover's surroundings on sol (or Martian day) 959 of its surface mission.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  3. The preliminary SOL (Sizing and Optimization Language) reference manual

    NASA Technical Reports Server (NTRS)

    Lucas, Stephen H.; Scotti, Stephen J.

    1989-01-01

    The Sizing and Optimization Language, SOL, a high-level special-purpose computer language has been developed to expedite application of numerical optimization to design problems and to make the process less error-prone. This document is a reference manual for those wishing to write SOL programs. SOL is presently available for DEC VAX/VMS systems. A SOL package is available which includes the SOL compiler and runtime library routines. An overview of SOL appears in NASA TM 100565.

  4. Sol-gel kinetics by NMR

    SciTech Connect

    Assink, R.A.; Kay, B.D.

    1991-01-01

    The chemical synthesis of advanced ceramic and glass materials by the sol-gel process has become an area of increasing activity in the field of material science. The sol-gel process provides a means to prepare homogeneous, high purity materials with tailored chemical and physical properties. This paper surveyed the nuclear magnetic resonance (NMR) studies of silicon-based sol-gel kinetics. A review of the various models which have been used to analyze the chemical kinetics of various sol-gel systems was presented. The utility of NMR spectroscopy was demonstrated in investigating the influence that various reaction conditions have on the reaction pathways by which sol-gel derived materials are synthesized. By observing in a direct fashion the chemical pathway of the sol-gel, it is often possible to relate the final properties of the material to the formulation and reaction conditions of the sol-gel. The study of reaction kinetics by NMR is expected to play an increasingly important role in understanding sol-gel processing and material properties. 15 refs. (DP)

  5. Diffusion dans les liquides

    NASA Astrophysics Data System (ADS)

    Dianoux, A. J.

    2003-09-01

    Après une brève introduction qui rappelle les concepts détaillés dans le cours de M. Bée, nous présentons un aperçu de trois de nos travaux sur l'étude de la diffusion. Tout d'abord la dynamique de l'eau, dans son état normal ou surfondu, révèle la complexité apportée par le réseau de liaisons hydrogène. Ensuite l'effet du confinement sur la dynamique de l'eau sera étudié dans le cas de la membrane Nafion. Enfin la diffusion dans les phases nématique et smectique A d'un cristal liquide permet d'obtenir la valeur du potentiel qui maintient les couches dans la phase smectique.

  6. Permanent Habitats in Earth-Sol/Mars-Sol Orbit Positions

    NASA Astrophysics Data System (ADS)

    Greenspon, J.

    Project Outpost is a manned Earth-Sol/Mars-Sol platform that enables permanent occupation in deep space. In order to develop the program elements for this complex mission, Project Outpost will rely primarily on existing/nearterm technology and hardware for the construction of its components. For the purposes of this study, four mission requirements are considered: 1. Outpost - Man's 1st purpose-produced effort of space engineering, in which astructure is developed/constructed in an environment completely alien to currentpractices for EVA guidelines. 2. Newton - a concept study developed at StarGate Research, for the development ofa modified Hohmann personnel orbital transport operating between Earth andMars. Newton would serve as the primary crew delivery apparatus throughrepeatable transfer scheduling for all Earth-Lpoint-Mars activities. Thispermanent "transit system" would establish the foundations for Solar systemcolonization. 3. Cruis - a concept study developed at StarGate Research, for the development of amodified Hohmann cargo orbital transport operating between Earth and Mars.Cruis would serve as the primary equipment delivery apparatus throughrepeatable transfer scheduling for all Earth-Lpoint-Mars activities. Thispermanent "transit system" would establish the foundations for Solar systemcolonization, and 4. Ares/Diana - a more conventional space platform configuration for Lunar andMars orbit is included as a construction baseline. The operations of these assetsare supported, and used for the support, of the outpost. Outpost would be constructed over a 27-year period of launch opportunities into Earth-Sol or Mars-Sol Lagrange orbit (E-S/M-S L1, 4 or 5). The outpost consists of an operations core with a self-contained power generation ability, a docking and maintenance structure, a Scientific Research complex and a Habitation Section. After achieving initial activation, the core will provide the support and energy required to operate the outpost in a 365

  7. Opportunity's View on Sol 354

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Opportunity captured this 360-degree panorama with its navigation camera on the rover's 354th martian day, or sol (Jan. 21, 2005). The view is presented as a cylindrical projection with geometric seam correction. Just to the right of center is the divot where Opportunity's heat shield hit the ground after protecting the spacecraft during descent through Mars'atmosphere. The heat shield was jettisoned about 90 seconds before Opportunity landed about 800 meters (half a mile) away. To the left of the divot is the flank portion of the heat shield debris and in the left foreground is the main wreckage of the heat shield. On the far right is a basketball-size rock dubbed 'Heat Shield Rock,' which Opportunity's inspection identified as an iron-nickel meteorite. The rim of 'Endurance Crater' is visible on the horizon on both the left and right ends of this full-circle view.

  8. SolTrace Optical Analysis Software

    Energy Science and Technology Software Center (ESTSC)

    2001-12-31

    SolTrace is a software package that models solar power optical systems and analyzes their performance. SolTrace can model parabolic trough collectors, point-focus concentrating systems, and power towers. It rapidly displays and saves data as scatter plots, flux maps, and performance graphs. SolTrace can model optical geometry as a series of stages, composed of optical elements that possess attributes such as shape, contour, and optical quality. It can also model any number of stages containing anymore » number of different elements, and it features an extensive variety of available shapes and contours.« less

  9. So, Why Sol-Mi? American Music Education

    ERIC Educational Resources Information Center

    Bennett, Peggy D.

    2005-01-01

    Walk into any primary grade music class in the U.S., and you will likely hear teacher and students singing a musical greeting, such as "Good morning boys and girls" (sol-mi-mi-sol-sol-mi) and the response "Good morning Miss Purdy" (sol-mi-mi-sol-mi-mi). Since about the 1970s, teachers have been beginning and ending music class for young children…

  10. Sol-gel antireflective coating on plastics

    DOEpatents

    Ashley, C.S.; Reed, S.T.

    1988-01-26

    An antireflection film made from reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  11. Sol-gel antireflective coating on plastics

    DOEpatents

    Ashley, Carol S.; Reed, Scott T.

    1990-01-01

    An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  12. Sol-gel deposited electrochromic coatings

    SciTech Connect

    Ozer, N.; Lampert, C.M.

    1995-06-01

    Electrochromic devices have increasing application in display devices, switchable mirrors and smart windows. A variety of vacuum deposition technologies have been used to make electrochromic devices. The sol- gel process offers an alternative approach to the synthesis of optical quality and low cost electrochromic device layers. This study summarizes the developments in sol-gel deposited electrochromic films. The sol-gel process involves the formation of oxide networks upon hydrolysis-condensation of alkoxide precursors. In this study we cover the sol-gel deposited oxides of WO[sub 3], V[sub 2]O[sub 5], TiO[sub 2], Nb[sub 2]O[sub 5], and NiO[sub x].

  13. Crater Rim Path, Sol 1,215

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The route followed by NASA's Mars Exploration Rover Opportunity during its exploration partway around the rim of Victoria Crater is marked on this map. The rover first reached the edge of the crater on it's 951st Martian day, or sol (Sept. 26, 2006). This map shows travels through sol 1,215 (June 24, 2007). The underlying image is from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

  14. Spirit 360-Degree View, Sol 388 (vertical)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 388th martian day, or sol (Feb. 4, 2005). Spirit had driven about 13 meters (43 feet) uphill toward 'Cumberland Ridge' on this sol. This location is catalogued as Spirit's Site 102, Position 513. The view is presented in a vertical projection with geometric and brightness seam correction.

  15. Spirit 360-Degree View, Sol 388

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 388th martian day, or sol (Feb. 4, 2005). Spirit had driven about 13 meters (43 feet) uphill toward 'Cumberland Ridge' on this sol. This location is catalogued as Spirit's Site 102, Position 513. The view is presented in a cylindrical projection with geometric and brightness seam correction.

  16. Spirit 360-Degree View, Sol 388 (polar)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 388th martian day, or sol (Feb. 4, 2005). Spirit had driven about 13 meters (43 feet) uphill toward 'Cumberland Ridge' on this sol. This location is catalogued as Spirit's Site 102, Position 513. The view is presented in a cylindrical projection with geometric and brightness seam correction.

  17. Sol-Gels for Optical Sensors

    NASA Astrophysics Data System (ADS)

    Podbielska, Halina; Ulatowska-Jarża, Agnieszka; Müller, Gerhard; Eichler, Hans J.

    Sol-gel process allows for formation of glassy and ceramics materials in temperatures much lower than offered by conventional melting techniques. The first paper on sol-gels was published over 150 years ago by Ebelmen, however, the rapid development of this technology and applications occurred in the last few years. There is a broad range of possible applications of solgel derived materials, what marked this technology as one of the most promising fields of contemporary material sciences

  18. Sol-gel method for encapsulating molecules

    DOEpatents

    Brinker, C. Jeffrey; Ashley, Carol S.; Bhatia, Rimple; Singh, Anup K.

    2002-01-01

    A method for encapsulating organic molecules, and in particular, biomolecules using sol-gel chemistry. A silica sol is prepared from an aqueous alkali metal silicate solution, such as a mixture of silicon dioxide and sodium or potassium oxide in water. The pH is adjusted to a suitably low value to stabilize the sol by minimizing the rate of siloxane condensation, thereby allowing storage stability of the sol prior to gelation. The organic molecules, generally in solution, is then added with the organic molecules being encapsulated in the sol matrix. After aging, either a thin film can be prepared or a gel can be formed with the encapsulated molecules. Depending upon the acid used, pH, and other processing conditions, the gelation time can be from one minute up to several days. In the method of the present invention, no alcohols are generated as by-products during the sol-gel and encapsulation steps. The organic molecules can be added at any desired pH value, where the pH value is generally chosen to achieve the desired reactivity of the organic molecules. The method of the present invention thereby presents a sufficiently mild encapsulation method to retain a significant portion of the activity of the biomolecules, compared with the activity of the biomolecules in free solution.

  19. Novel sol-gel bioactive fibers.

    PubMed

    Oréfice, R L; Hench, L L; Clark, A E; Brennan, A B

    2001-06-15

    Bioactive fibers were produced using a sol-gel method. The rheological properties of two different sol compositions prepared from a mixture of TEOS, phosphorous alkoxide and calcium nitrate, or calcium chloride in a water-ethanol solution, are reported. The sols were extruded through a spinneret to produce continuous 10 microm-diameter fibers. Discontinuous fibers and fibrous mats were prepared by air-spraying the multicomponent sols. The sol-gel fibers were converted to the bioactive fibers by three different thermal treatments at either 600 degrees, 700 degrees, or 900 degrees C for 3 h. SEM, BET, EDX, and FTIR were used to characterize the morphology and structure of the fibers. The BET measured surface area of the fibers sintered at 900 degrees C was 0 m(2)/gm compared to a value of 200 m(2)/gm for a typical sol-gel-derived particle of similar composition. Both the continuous and discontinuous fibers exhibited in vitro bioactivity in a simulated body fluid. PMID:11288073

  20. Gusev Dust Devil, Sol 543

    NASA Technical Reports Server (NTRS)

    2005-01-01

    One dust devil scoots across the center of the view in this movie clip showing a few dust devils inside Mars' Gusev Crater. The clip consists of frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 543rd martian day, or sol (July 13, 2005).

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.

    In this clip, contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust moved by wind. The total time elapsed during the taking of these frames was 8 minutes, 21 seconds.

  1. Gusev Dust Devil, sol 532

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil seen by NASA's Mars Exploration Rover Spirit during the rover's 532nd martian day, or sol (July 2, 2005). The dust-carrying whirlwind is moving across a plain inside Gusev Crater and viewed from Spirit's vantage point on hills rising from the plain. The clip consists of frames taken by Spirit's navigation camera, processed to enhance contrast for anything in the images that changes from frame to frame. The total elapsed time during the taking of these frames was 8 minutes, 48 seconds.

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.

  2. Coherent Structures in the SOL

    NASA Astrophysics Data System (ADS)

    Aydemir, A. Y.

    2004-11-01

    Long-time simulations of density ``blobs'' in the tokamak scrape-off layer show that most cannot be categorized as ``coherent structures.'' Born near the separatrix, blobs are expected to propagate a distance 5-10 times their own linear dimensions before reaching the chamber walls. Using a simple two-field model commonly used in the literature, we find that small, fast-moving blobs go unstable to Kelvin-Helmholtz modes, as also observed by previous workers. Nonlinearly, these modes lead to repeated vortex-shedding, with its accompanying mass loss, leaving behind only a small fraction of the original blob mass. Large, slow-moving blobs, on the other hand, tend to be unstable to Rayleigh-Taylor modes. The ``RT Fingers'' quickly and violently break up the blob into smaller filaments that continue to propagate radially as they spread the mass poloidally. In this case, only a diffuse cloud of particles makes it to the wall. Blobs of the ``correct size'', however, do behave coherently, retaining most of their original mass. These coherent structures exhibit a steepened leading edge that remains KH-stable, and a long tail. Together, these characteristics agree with the experimental observations for ``intermittent-events'' in the SOL with steep rise and slow decay times. Extension of this work to 3D using a more sophisticated physics-model is being contemplated.

  3. Modelisation du Signal Radar EN Milieu Stratifie et Evaluation de Techniques de Mesure de L'humidite du Sol

    NASA Astrophysics Data System (ADS)

    Boisvert, Johanne

    La presente etude se penche sur des problemes relies a l'echantillonnage de l'humidite de sol et a l'estimation du signal radar sur sols nus. Le travail se divise en deux volets. Le volet 1 evalue trois techniques de mesure de l'humidite du sol (gravimetrie, reflectometrie temporelle et sonde dielectrique) et deux protocoles d'echantillonnage. Dans le volet 2, un modele de simulation du signal en milieu stratifie est developpe, et les estimes de signal obtenus sont compares aux estimes bases uniquement sur une valeur moyenne d'humidite du sol prise sur une profondeur fixe d'echantillonnage. Les differences entre les deux estimes dependent de la frequence et du choix judicieux de la profondeur d'echantillonnage; elles sont plus importantes aux faibles angles et en polarisation HV, puis VV. Le modele de simulation a aussi ete utilise pour etudier la profondeur de penetration du signal et en deduire la profondeur optimale d'echantillonnage en tenant compte des caracteristiques du signal. Une variation de 25 ^circ de l'angle d'incidence a peu d'effet sur la profondeur de penetration en bande Ku; l'ecart reste inferieur ou egal a 0,5 cm en bande C mais peut atteindre 1,3 cm en bande L. L'impact de la polarisation est nul en bande Ku mais croi t avec l'angle d'incidence en bande C et L. A 50^circ, il est, en moyenne de 1 cm en bande C et de 2 cm en bande L. En polarisation VV, la profondeur croi t avec une augmentation de l'angle alors que l'effet est inverse en polarisation HH. Deux methodes pour estimer la profondeur d'echantillonnage en conditions operationnelles sont presentees. Lorsqu'on inverse un modele pour estimer l'humidite du sol a partir du signal, ces methodes permettent aussi d'estimer l'epaisseur de sol representee par l'humidite ainsi estimee.

  4. Les aspects psychosociaux de l’obésité chez les enfants et les adolescents

    PubMed Central

    Nieman, Peter; LeBlanc, Claire MA

    2012-01-01

    RÉSUMÉ En plus de donner des conseils aux familles au sujet de l’activité physique régulière et d’une saine alimentation, les cliniciens doivent déterminer les facteurs psychosociaux qui contribuent à l’obésité des enfants ou des adolescents et les aider à y faire face. Les personnes touchées peuvent souffrir de dépression, de mauvaise estime de soi, d’intimidation et de préjugés liés au poids, qui sont tous des expériences qui peuvent compliquer l’obtention des résultats de santé souhaités. Les cliniciens devraient tenter de déterminer les facteurs stressants sous-jacents et s’assurer de la mise en œuvre de conseils pertinents.

  5. Toward sol-gel-based sensors

    SciTech Connect

    Jordan, J.D.; Ingersoll, C.M.; Dunbar, R.A.

    1995-12-31

    Advances in biotechnology have produced a variety of antibodies and other biomolecules that possess selective recognition capabilities. Current techniques for the immobilization of these biomolecules typically involve multistep derivatization of a primary substrate, which is labor intensive and often requires large volumes of costly reagents. Further, these immobilization chemistries often adversely affect the characteristic properties of the protein (e.g., the binding affinity). As a result, the need for fast, accurate, inexpensive, and simple to operate diagnostic assays escalates. Because of their room temperature processing, transparency, inertness, and tunable pore structure, sol-gel-derived composites represent promising chemical and biosensing platforms. To date, many researchers have entrapped proteins and enzymes in sol-gel monoliths, and found that they retain some of their native properties. Our group first reported on the affinity of a sol-gel entrapped antibody. However, although these biogel monoliths were promising, analyte diffusion through the monolith matrix is slow, resulting in long response times. Thus, it is clear that the next level of sol-gel-derived biosensor must depend on thin film technology. In the current work, the affinity of fluorescein entrapped within a sol-gel derived thin film for the anti fluorescent hapten, 5- (and 6-)-carboxy 4{prime}, 5{prime}-dimethylfluorescein, is investigated. A novel film preparation technique will be introduced, and the response and response times of these films as a function of processing and storage conditions will be discussed.

  6. Digging Movie from Phoenix's Sol 18

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander recorded the images combined into this movie of the lander's Robotic Arm enlarging and combining the two trenches informally named 'Dodo' (left) and 'Goldilocks.'

    The 21 images in this sequence were taken over a period of about 2 hours during Phoenix's Sol 18 (June 13, 2008), or the 18th Martian day since landing.

    The main purpose of the Sol 18 dig was to dig deeper for learning the depth of a hard underlying layer. A bright layer, possibly ice, was increasingly exposed as the digging progressed. Further digging and scraping in the combined Dodo-Goldilocks trench was planned for subsequent sols.

    The combined trench is about 20 centimeters (about 8 inches) wide. The depth at the end of the Sol 18 digging is 5 to 6 centimeters (about 2 inches).

    The Goldilocks trench was the source of soil samples 'Baby Bear' and 'Mama Bear,' which were collected on earlier sols and delivered to instruments on the lander deck. The Dodo trench was originally dug for practice in collecting and depositing soil samples.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Upgrades for TwinSol facility

    NASA Astrophysics Data System (ADS)

    O'Malley, P. D.; Bardayan, D. W.; Kolata, J. J.; Hall, M. R.; Hall, O.; Allen, J.; Becchetti, F. D.

    2016-06-01

    TwinSol, a pair of coupled, superconducting solenoids, was one of the first devices capable of producing beams of radioactive nuclei at energies near the Coulomb barrier. A primary beam from University of Notre Dame (UND) tandem accelerator is used to bombard a primary target producing a secondary beam in flight. TwinSol is used to gather, separate, and focus the recoils. Since it was commissioned at the UND in 1997, at least 58 publications have reported data from its use and there have been hundreds of collaborators from many different countries that use this device. Currently, plans are in place at the UND to provide several upgrades to TwinSol, including a multi-cell gas production target and the possible addition of a third solenoid. Upgrades currently in progress will be discussed along with future plans.

  8. Opportunity's Surroundings on Sol 1687 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008).

    Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction.

    Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast.

    This view is presented as a polar projection with geometric seam correction.

  9. Before & After of Rasping on Sol 56

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This animation combines two images of the trench informally named 'Snow White' taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander on July 21, 2008, during the lander's 56th Martian day, or sol, since landing.

    The earlier Sol 56 image is the one without a shadow falling across the lower right corner of the image. It was taken after Phoenix had used its motorized rasp to get some material from the trench into the scoop on the lander's robotic arm. The later Sol 56 image was taken after the arm had scraped clean an area that includes the rasping site.

    The trench is about 23 centimeters (9 inches) wide. These images were taken through the camera's red filter.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. Opportunity's Surroundings on Sol 1687 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008).

    Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction.

    Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast.

    This view is presented as a vertical projection with geometric seam correction.

  11. Neutron detector using sol-gel absorber

    SciTech Connect

    Hiller, J.M.; Wallace, S.A.; Dai, S.

    1999-10-26

    An neutron detector composed of fissionable material having ions of lithium, uranium, thorium, plutonium, or neptunium, contained within a glass film fabricated using a sol-gel method combined with a particle detector is disclosed. When the glass film is bombarded with neutrons, the fissionable material emits fission particles and electrons. Prompt emitting activated elements yielding a high energy electron contained within a sol-gel glass film in combination with a particle detector is also disclosed. The emissions resulting from neutron bombardment can then be detected using standard UV and particle detection methods well known in the art, such as microchannel plates, channeltrons, and silicon avalanche photodiodes.

  12. Neutron detector using sol-gel absorber

    DOEpatents

    Hiller, John M.; Wallace, Steven A.; Dai, Sheng

    1999-01-01

    An neutron detector composed of fissionable material having ions of lithium, uranium, thorium, plutonium, or neptunium, contained within a glass film fabricated using a sol-gel method combined with a particle detector is disclosed. When the glass film is bombarded with neutrons, the fissionable material emits fission particles and electrons. Prompt emitting activated elements yielding a high energy electron contained within a sol-gel glass film in combination with a particle detector is also disclosed. The emissions resulting from neutron bombardment can then be detected using standard UV and particle detection methods well known in the art, such as microchannel plates, channeltrons, and silicon avalanche photodiodes.

  13. Spirit 360-Degree View on Sol 409

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 409th martian day, or sol (Feb. 26, 2005). Spirit had driven 2 meters (7 feet) on this sol to get in position on 'Cumberland Ridge' for looking into 'Tennessee Valley' to the east. This location is catalogued as Spirit's Site 108. Rover-wheel tracks from climbing the ridge are visible on the right. The summit of 'Husband Hill' is at the center, to the south. This view is presented in a cylindrical projection with geometric and brightness seam correction.

  14. Spirit Beside 'Home Plate,' Sol 1809

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA Mars Exploration Rover Spirit used its navigation camera to take the images assembled into this 120-degree view southward after a short drive during the 1,809th Martian day, or sol, of Spirit's mission on the surface of Mars (February 3, 2009).

    Spirit had driven about 2.6 meters (8.5 feet) that sol, continuing a clockwise route around a low plateau called 'Home Plate.' In this image, the rocks visible above the rovers' solar panels are on the slope at the northern edge of Home Plate.

    This view is presented as a cylindrical projection with geometric seam correction.

  15. Sol-Gel Synthesis Of Aluminoborosilicate Powders

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Leiser, Daniel; Selvaduray, Guna

    1992-01-01

    Application of sol-gel process to synthesis of aluminoborosilicate powders shows potential for control of microstructures of materials. Development of materials having enhanced processing characteristics prove advantageous in extending high-temperature endurance of fibrous refractory composite insulation made from ceramic fibers.

  16. Opportunity's View After Drive on Sol 1806

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction.

    The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a cylindrical projection with geometric seam correction.

  17. Volume Changes of a Thixotropic, Sodium Bentonite Suspension during Sol-Gel-Sol Transition.

    PubMed

    Anderson, D M; Leaming, G F; Sposito, G

    1963-09-13

    Dilatometric measurements during the sol-gel-sol transition of an air-free, thixotropic, sodium bentonite suspension revealed a reversible change in volume of about 2.4 X 10(-4) percent. The volume of the suspension increased during gelation and decreased when the gel was subsequently liquified. This is taken as evidence of a progressive building up, during gelation, of a water structure less dense than normal. PMID:17739493

  18. Les violences conjugales à Dakar

    PubMed Central

    Soumah, Mohamed Maniboliot; Issa, Abdoul Wahab; Ndiaye, Mor; Ndoye, El Hadj Oumar; Sow, Mamadou Lamine

    2015-01-01

    L'objectif était d’évaluer les aspects épidémiologiques des violences conjugales, identifier les facteurs de risques et les différents types de violences conjugales, évaluer les conséquences des violences conjugales sur la santé des victimes, afin d'améliorer la prise en charge des victimes et la prévention du phénomène. Il s'est agit d'une étude transversale effectuée de décembre 2012 à janvier 2013 à Dakar. Les données ont été recueillies, après consentement, sur fiche d'enquête anonyme soumise à toute personne volontaire vivant en couple et résidant à Dakar. L'analyse statistique a été effectuée avec le logiciel SPSS 13.0. Le nombre de personnes victimes de violences conjugales était de 60 soit 37,30% dont 31 femmes (51,70%) et 29 hommes (48,30%). Le sex-ratio était de 0,93. Parmi les victimes, 53 étaient scolarisées soit 88,30%. Le régime matrimonial était de type monogame dans 39 cas (65%) et polygame dans 21 cas (35%). La vie en couple durait depuis moins de 11 ans dans 60% des cas et durait de 11 ans à 20 ans au plus dans 26,6% des cas. L’étude des types de violences montrait la fréquence des agressions physiques. Les armes utilisées étaient surtout les armes naturelles. Les principaux facteurs de risque de violence conjugale sont les facteurs sociodémographiques, culturels et économiques comme le jeune âge, l'inégalité du genre, les jeunes couples, la précarité, le niveau d'instruction élevé. La prise en charge des victimes et la prévention du phénomène restent insuffisantes dans nos pays. PMID:26918077

  19. Comparison of effectiveness of sub-slab ventilation systems for indoor radon mitigation: A numerical study; Comparaison a l`aide d`un outil numerique de l`efficacite des systemes de ventilation active du sol limitant la penetration du radon dans l`habitat

    SciTech Connect

    Bonnefous, Y.C. |; Gadgil, A.J.; Allard, F.

    1992-04-01

    The functioning of an active sub-slab ventilation system (SVS) has been studied successfully with the help of a previously evaluated numerical model. The parameters explored are the permeability of the sub-slab and the gravel placed beneath it, the amplitude of applied pressure at the installation point of the system and the functioning method: depressurization or pressurization. The mechanisms contributing to the success of the two systems are identified. This numerical study shows that the presence of a layer of gravel beneath the sub-slab considerably improves the performance of the SVS. Considered separately from the extremely permeable sub-slabs, the depressurization systems perform better than the pressurization systems. 17 refs. [Francais] Le fonctionnement des Systemes de Ventilation active du Sol (SVS) a ete etudie a l`aide d`un outil numerique precedemment evalue avec succes. Les parametres explores sont les permeabilites du sol et du gravier place sous plancher bas, l`amplitude de la pression appliquee au point d`installation du systeme, et le mode de fonctionnement: Depressurisation ou Pressurisation. Les mecanismes contribuant au succes des deux systemes sont identifies. Cette etude numerique montre que la presence d`une couche de gravier sous plancher bas ameliore de facon considerable les performances des SVS. Mis a part le cas des sols extremement permeables, les systemes de Depressurisation ont de meilleures performances que les systemes de Pressurisation. 17 refs.

  20. Sol-gel processing of metal sulfides

    NASA Astrophysics Data System (ADS)

    Stanic, Vesha

    Metal sulfides were synthesised via a sol-gel process using various metal alkoxides and hydrogen sulfide in toluene. Colloidal gels were prepared from germanium ethoxide, germanium isopropoxide, zinc tert-butoxide and tungsten (VI) ethoxide, whereas colloidal powder was produced from tungsten (V) dichloride ethoxide. Special precautions were necessary to protect the reaction mixture from water contamination which produced metal oxides. Results indicated that the main source of water is the hydrogen sulfide gas. In addition, synthesis of metal sulfides from a mixture of metal oxide and sulfide was demonstrated by the example of monoclinic germanium disulfide. It was produced by reaction of the sol-gel product with sulfur. Heat treatment of the sol-gel product and sulfur yielded single phase GeSsb2. The sol-gel prepared materials and their heat treated products were characterized by various methods. A chemical kinetics study of the functional groups -OR, -SH and Ssp{2-} was carried out for the sol-gel processing of GeSsb2 from of hydrogen sulfide and two different alkoxides, germanium ethoxide and germanium isopropoxide. The study was performed for different concentrations of precursors at different molar ratios and temperatures. The results indicate that the proposed reaction mechanism was simplified under appropriate reaction conditions. Experimentally determined rate constants of thiolysis and condensations demonstrate that thiolysis is slow and that condensations are fast steps, regardless of the studied reaction conditions. A study of the temperature effect on the reaction rate constant shows that it increases with temperature in accord with both Arrhenius law and transition-state theory. Activation energies, Esba, and activation parameters DeltaSsp{ddagger}, DeltaHsp{ddagger} and DeltaGsp{ddagger}, were determined for thiolysis and condensation reactions. The potentiometric tiration method was used for quantitative determination of germanium sulfide and

  1. Droplet Spreading with Sol-Gel Transition

    NASA Astrophysics Data System (ADS)

    Jalaal, Maziyar; Stoeber, Boris; Balmforth, Neil J.

    2014-11-01

    The impact and spreading of liquid droplets on a smooth solid substrate is a classical subject with several industrial applications such as ink-jet printing, spray cooling, coating, and many others. For many of these deposition processes, controlling the final shape of the drop is critical. In the current research, a new technique for controlling the spreading of droplets impacting a substrate is presented. This technique exploits the rheology of a thermo-responsive polymer solution that undergoes a reversible sol/gel transition above a critical temperature. Experiments are conducted using a combination of shadowgraphy and micro-PIV to observe spreading drops. It is shown that the final diameter of a droplet can be controlled through the temperature of the substrate and the tunable sol/gel transition temperature of the fluid.A mathematical model is provided to further elucidate the flow dynamics.

  2. Novel carboxy functionalized sol-gel precursors

    SciTech Connect

    Wolter, H.; Storch, W.; Gellermann, C.

    1996-12-31

    A novel family of inorganic-organic copolymers (ORMOCER`s) derived from urethane- and thioether(meth)acrylate alkoxysilanes has been successfully exploited for a variety of diverse applications. In order to widen the range of applications an additional functionality (carboxy group) has been incorporated int his silane type. Conventional sol-gel processing facilitates the formation of an inorganic Si-O-Si-network via hydrolysis and polycondensation reactions of alkoxysilyl moieties and in addition, the (meth)acrylate groups are available for radically induced polymerization to obtain a complementary organic polymer structure. The presence of a carboxy group would appear to have great potential for a range of diverse areas of application, such as an internal catalyst for the sol-gel process, complexation of elements such as Zr and Ti, increasing the adhesion to various substrates and modification of solubility. A number of novel silanes and their syntheses will be described in this paper.

  3. Phoenix Robotic Arm's Workspace After 90 Sols

    NASA Technical Reports Server (NTRS)

    2008-01-01

    During the first 90 Martian days, or sols, after its May 25, 2008, landing on an arctic plain of Mars, NASA's Phoenix Mars Lander dug several trenches in the workspace reachable with the lander's robotic arm.

    The lander's Surface Stereo Imager camera recorded this view of the workspace on Sol 90, early afternoon local Mars time (overnight Aug. 25 to Aug. 26, 2008). The shadow of the the camera itself, atop its mast, is just left of the center of the image and roughly a third of a meter (one foot) wide.

    The workspace is on the north side of the lander. The trench just to the right of center is called 'Neverland.'

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. Opportunity's View on Sols 1803 and 1804

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,803rd and 1,804th Martian days, or sols, of Opportunity's surface mission (Feb. 18 and 19, 2009). South is at the center; north at both ends.

    The rover had driven 55 meters on Sol 1803 before beginning to take the frames in this view. Tracks from that drive recede northward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical projection with geometric seam correction.

  5. Opportunity's Surroundings After Sol 1820 Drive

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). South is at the center; north at both ends.

    The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

    This view is presented as a cylindrical projection with geometric seam correction.

  6. Opportunity's Surroundings After Sol 1820 Drive (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009).

    This view is presented as a polar projection with geometric seam correction. North is at the top.

    The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

  7. Opportunity's Surroundings on Sol 1818 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends.

    This view is presented as a polar projection with geometric seam correction. North is at the top.

    The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view.

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  8. Opportunity's Surroundings After Sol 1820 Drive (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009).

    This view is presented as a vertical projection with geometric seam correction. North is at the top.

    The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

  9. Opportunity's Surroundings on Sol 1818 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends.

    This view is presented as a vertical projection with geometric seam correction. North is at the top.

    The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view.

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  10. Opportunity's Surroundings on Sol 1798 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top.

    This view is presented as a vertical projection with geometric seam correction.

    The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  11. Opportunity's Surroundings on Sol 1798 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top.

    This view is presented as a polar projection with geometric seam correction.

    The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

  12. Impediment to Spirit Drive on Sol 1806

    NASA Technical Reports Server (NTRS)

    2009-01-01

    The hazard avoidance camera on the front of NASA's Mars Exploration Rover Spirit took this image after a drive by Spirit on the 1,806th Martian day, or sol, (January 31, 2009) of Spirit's mission on the surface of Mars.

    The wheel at the bottom right of the image is Spirit's right-front wheel. Because that wheel no longer turns, Spirit drives backwards dragging that wheel. The drive on Sol 1806 covered about 30 centimeters (1 foot). The rover team had planned a longer drive, but Spirit stopped short, apparently from the right front wheel encountering the partially buried rock visible next to that wheel.

    The hazard avoidance cameras on the front and back of the rover provide wide-angle views. The hill on the horizon in the right half of this image is Husband Hill. Spirit reached the summit of Husband Hill in 2005.

  13. Innovative materials based on sol gel technology

    NASA Astrophysics Data System (ADS)

    Reisfeld, Renata; Saraidarov, Tsiala

    2006-01-01

    We review the sol-gel based new materials which were prepared in our laboratory including: tunable lasers, active waveguides, luminescent solar concentrators, electrochromic, photochromic and gasochromic plates for smart windows, chemical and biological sensors, semiconductor quantum dots and complexes of rare earth ions. In this paper we present the firstly obtained results of the Eu sulfide nanocrystalline (NCs) powder material and doped in the sol-gel based zirconia films. The powder and films were studied by high resolution transmittance electron microscopy (HRTEM), energy dispersive X-ray spectroscopy analysis (EDS) and luminescence spectroscopy. Eu sulfide nanocrystals (NCs) ranging between 8 and 10 nm were obtained as powder and 3-4 nm incorporated in zirconia film.

  14. Ring-Resonator/Sol-Gel Interferometric Immunosensor

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory; Cohen, David

    2007-01-01

    A proposed biosensing system would be based on a combination of (1) a sensing volume containing antibodies immobilized in a sol-gel matrix and (2) an optical interferometer having a ring resonator configuration. The antibodies would be specific to an antigen species that one seeks to detect. In the ring resonator of the proposed system, light would make multiple passes through the sensing volume, affording greater interaction length and, hence, greater antibody- detection sensitivity.

  15. Spirit Near 'Stapledon' on Sol 1802 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top.

    This view is presented as a polar projection with geometric seam correction.

    Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

    Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

    The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

  16. Spirit Near 'Stapledon' on Sol 1802

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. South is at the center; north is at both ends.

    Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

    Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

    The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

    This view is presented as a cylindrical projection with geometric seam correction.

  17. Spirit Near 'Stapledon' on Sol 1802 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top.

    This view is presented as a vertical projection with geometric seam correction.

    Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

    Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

    The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

  18. SOL Width Scaling in the MAST Tokamak

    NASA Astrophysics Data System (ADS)

    Ahn, Joon-Wook; Counsell, Glenn; Connor, Jack; Kirk, Andrew

    2002-11-01

    Target heat loads are determined in large part by the upstream SOL heat flux width, Δ_h. Considerable effort has been made in the past to develop analytical and empirical scalings for Δh to allow reliable estimates to be made for the next-step device. The development of scalings for a large spherical tokamak (ST) such as MAST is particularly important both for development of the ST concept and for improving the robustness of scalings derived for conventional tokamaks. A first such scaling has been developed in MAST DND plasmas. The scaling was developed by flux-mapping data from the target Langmuir probe arrays to the mid-plane and fitting to key upstream parameters such as P_SOL, bar ne and q_95. In order to minimise the effects of co-linearity, dedicated campaigns were undertaken to explore the widest possible range of each parameter while keeping the remainder as fixed as possible. Initial results indicate a weak inverse dependence on P_SOL and approximately linear dependence on bar n_e. Scalings derived from consideration of theoretical edge transport models and integration with data from conventional devices is under way. The established scaling laws could be used for the extrapolations to the future machine such as Spherical Tokamak Power Plant (STPP). This work is jointly funded by Euratom and UK Department of Trade and Industry. J-W. Ahn would like to recognise the support of a grant from the British Foreign & Commonwealth Office.

  19. Sol-Gel Manufactured Energetic Materials

    DOEpatents

    Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

    2005-05-17

    Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

  20. Sol-gel manufactured energetic materials

    DOEpatents

    Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

    2003-12-23

    Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

  1. Opportunity's Surroundings on Sol 1687 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11739 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11739

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008). The view appears three-dimensional when viewed through red-blue glasses.

    Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction.

    Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast.

    This panorama combines right-eye and left-eye views presented as cylindrical-perspective projections with geometric seam correction.

  2. Sol-gel processing to form doped sol-gel monoliths inside hollow core optical fiber and sol-gel core fiber devices made thereby

    NASA Technical Reports Server (NTRS)

    Shaw, Harry C. (Inventor); Ott, Melanie N. (Inventor); Manuel, Michele V. (Inventor)

    2002-01-01

    A process of fabricating a fiber device includes providing a hollow core fiber, and forming a sol-gel material inside the hollow core fiber. The hollow core fiber is preferably an optical fiber, and the sol-gel material is doped with a dopant. Devices made in this manner includes a wide variety of sensors.

  3. Ionogel Electrolytes through Sol-Gel Processing

    NASA Astrophysics Data System (ADS)

    Horowitz, Ariel I.

    Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica

  4. Une vie active saine pour les enfants et les adolescents

    PubMed Central

    2002-01-01

    De mauvais modes de vie, comme une alimentation malsaine et l’inactivité physique, sont d'importants facteurs contributifs à une augmentation de la morbidité et de la mortalité secondaires à des maladies chroniques à l’âge adulte. Depuis dix ans, on remarque une augmentation du mode de vie sédentaire et de l’obésité chez les enfants et les adolescents, tant en Amérique du Nord qu’ailleurs dans le monde. Les médecins doivent être conscients de l’importance du problème, fournir des conseils de prévention aux familles et promouvoir une vie active saine dans leur pratique.

  5. ["Les Impatients": expression through art].

    PubMed

    Lamontagne, Céline; Palardy, Lorraine

    2015-01-01

    The organization called "Les Impatients" was founded in 1992. Using a unique model, Les Impatients welcomes those with mental health issues who would like to express themselves through art. Les Impatients offers free creative workshops and encourages exchanges with the community through the sharing of its participants' creations. The name Les Impatients reinforces the idea that the organization does not consider those attending its workshops as patients, but rather creators who are eager to heal, develop their craft and find their place in society. The participants contribute to the collective objective of breaking down the stigma that surrounds mental illness.Les Impatients collaborates with various mental health organizations in Quebec, such as the Institut universitaire en santé mentale de Montréal (IUSMM) affiliated to the Université de Montréal, Douglas Mental Health University Institute (DMHUI), the Centre de santé et services sociaux Drummond (CSSS Drummond) and the Centre de santé et services sociaux Pierre-Boucher (CSSS Pierre-Boucher). Les Impatients offers more than 48 workshops in eight different locations to around 450 participants each week.Dissemination activities, remarkable events, original projects: Les Impatients stands out through its realizations. Examples are exhibitions, collections of love letters, comic books, CD, concerts, and reading nights. The organization's originality resides in the exploration of the links between the work of the participants and that of professional artists. An illustration of this interest is the annual Parle-moi d'amour auction-exhibition, which has been one of Les Impatients' major events since 1999.As part of its mission, Les Impatients conserves the works of art created by the participants during the workshops. Its collection includes more than 15,000 works of art from Les Impatients as well as pieces donated by collectors of unconventional art, commonly known as "art brut" or "outsider art". The

  6. NMR of molecules trapped in sol-gel glasses: Progressive closure of the nanoporosity during drying

    NASA Astrophysics Data System (ADS)

    Cros, F.; Malier, L.; Korb, J.-P.; Chaput, F.

    1998-02-01

    We characterize the closed porosity of porous hybrid organic-inorganic sol-gel matrices. 2H-nuclear relaxation of d16-adamantane confined in these pores evidences a molecular translational motion inside the porous network. The pores are shown to be interconnected at the submicrometric scale. By modelling the effect of interpore molecular jumps on the lineshape, we characterize the progressive closure of the nanoporosity during drying. Nous avons caractérisé la porosité de matrices hybrides organique-inorganiques poreuse, à porosité fermée, préparées par voie sol-gel. La relaxation nucléaire du deuterium de l'adamantane d16 confinée dans les pores de ces matériaux a mis en évidence un mouvement de translation de cette molécule à l'intérieur du système de pores, qui est en fait connexe à l'échelle sub-micrométrique. L'influence des sauts, d'un pore à un autre, sur la forme de raie nous a permis de caractériser la fermeture de ces pores au cours du séchage.

  7. Method of making particles from an aqueous sol

    DOEpatents

    Rankin, G.W.; Hooker, J.R.

    1973-07-24

    A process for preparing gel particles from an aqueous sol by forming the sol into droplets in a liquid system wherein the liquid phase contains a liquid organic solvent and a barrier agent. The barrier agent prevents dehydration from occurring too rapidly and permits surface tension effects to form sol droplets into the desired spheroidal shape. A preferred barrier agent is mineral oil. (Official Gazette)

  8. Sol gels. (Latest citations from Materials Business file). Published Search

    SciTech Connect

    1996-01-01

    The bibliography contains citations concerning sol gel derived materials. The citations examine research conducted by universities, corporations and government agencies for the development of novel sol gel processes, and commercial applications of these techniques. Uses of sol gels in the production of glass, ceramics, composites, protective coatings, and hybrid organic/inorganic materials are described. Other topics include new products, expanding markets for sol gel derived materials, and profit potential. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  9. Sol-gel processing with inorganic metal salt precursors

    DOEpatents

    Hu, Zhong-Cheng

    2004-10-19

    Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.

  10. Les plaies du tendon patellaire

    PubMed Central

    Mechchat, Atif; Elidrissi, Mohammed; Mardy, Abdelhak; Elayoubi, Abdelghni; Shimi, Mohammed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

    2014-01-01

    Les plaies du tendon patellaire sont peu fréquentes et sont peu rapportés dans la littérature, contrairement aux ruptures sous cutanées. Les sections du tendon patellaire nécessitent une réparation immédiate afin de rétablir l'appareil extenseur et de permettre une récupération fonctionnelle précoce. A travers ce travail rétrospectif sur 13 cas, nous analysons les aspects épidémiologiques, thérapeutiques et pronostiques de ce type de pathologie en comparant différents scores. L’âge moyen est de 25 ans avec une prédominance masculine. Les étiologies sont dominées par les accidents de la voie publique (68%) et les agressions par agent tranchant (26%) et contendant (6 %). Tous nos patients ont bénéficié d'un parage chirurgical avec suture tendineuse direct protégée par un laçage au fils d'aciers en légère flexion. La rééducation est débutée après sédation des phénomènes inflammatoires. Au dernier recul les résultats sont excellents et bon à 92%. Nous n'avons pas noté de différence de force musculaire et d'amplitude articulaire entre le genou sain et le genou lésé. Les lésions ouvertes du tendon patellaire est relativement rare. La prise en charge chirurgicale rapide donne des résultats assez satisfaisants. La réparation est généralement renforcée par un semi-tendineux, synthétique ou métallique en forme de cadre de renfort pour faciliter la réadaptation et réduire le risque de récidive après la fin de l'immobilisation. PMID:25170379

  11. 'Victoria' After Sol 950 Drive (Stereo)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA08778

    [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA08778 [figure removed for brevity, see original site] Cylindrical view for PIA08778

    A drive of about 30 meters (about 100 feet) on the 950th Martian day, or sol, of Opportunity's exploration of Mars' Meridiani Planum region (Sept. 25, 2006) brought the NASA rover to within about 20 meters (about 66 feet) of the rim of 'Victoria Crater.' From that position, the rover's navigation camera took the exposures combined into this stereo anaglyph, which appears three-dimensional when viewed through red-green glasses. The scalloped shape of the crater is visible on the left edge. Due to a small dune or ripple close to the nearest part of the rim, the scientists and engineers on the rover team planned on sol 951 to drive to the right of the ripple, but not quite all the way to the rim, then to proceed to the rim the following sol. The image is presented in cylindrical projection with geometric seam correction.

    Victoria Crater is about 800 meters (one-half mile) in diameter, about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and therefore, potentially preserving several times the historical record.

  12. Spirit's Surroundings on 'West Spur,' Sol 305

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a cylindrical projection with geometric seam correction.

  13. Fluoride glasses from sol gels. Final report

    SciTech Connect

    Uhlmann, D.R.

    1986-09-15

    The use of sol-gel coatings to strengthen oxide glasses was demonstrated for the case of fused silica. Increases in strength to as much as 2.2 times the strength of uncoated glass were obtained. The strengthening does not involve the annealing of surface microcracks, but rather the filling-in of such flaws. The strengthening does not depend on coating thickness over the range 2000-10000 Angstroms, but does depend significantly upon the state of hydrolysis of the substrate surface.

  14. Spirit Near 'Stapledon' on Sol 1802 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11781 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11781

    NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this stereo, full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. South is at the center; north is at both ends.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

    Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

    The team laid plans to drive Spirit from

  15. Validating LES for Jet Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.

    2011-01-01

    Engineers charged with making jet aircraft quieter have long dreamed of being able to see exactly how turbulent eddies produce sound and this dream is now coming true with the advent of large eddy simulation (LES). Two obvious challenges remain: validating the LES codes at the resolution required to see the fluid-acoustic coupling, and the interpretation of the massive datasets that are produced. This paper addresses the former, the use of advanced experimental techniques such as particle image velocimetry (PIV) and Raman and Rayleigh scattering, to validate the computer codes and procedures used to create LES solutions. This paper argues that the issue of accuracy of the experimental measurements be addressed by cross-facility and cross-disciplinary examination of modern datasets along with increased reporting of internal quality checks in PIV analysis. Further, it argues that the appropriate validation metrics for aeroacoustic applications are increasingly complicated statistics that have been shown in aeroacoustic theory to be critical to flow-generated sound, such as two-point space-time velocity correlations. A brief review of data sources available is presented along with examples illustrating cross-facility and internal quality checks required of the data before it should be accepted for validation of LES.

  16. Validating LES for Jet Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2011-01-01

    Engineers charged with making jet aircraft quieter have long dreamed of being able to see exactly how turbulent eddies produce sound and this dream is now coming true with the advent of large eddy simulation (LES). Two obvious challenges remain: validating the LES codes at the resolution required to see the fluid-acoustic coupling, and the interpretation of the massive datasets that result in having dreams come true. This paper primarily addresses the former, the use of advanced experimental techniques such as particle image velocimetry (PIV) and Raman and Rayleigh scattering, to validate the computer codes and procedures used to create LES solutions. It also addresses the latter problem in discussing what are relevant measures critical for aeroacoustics that should be used in validating LES codes. These new diagnostic techniques deliver measurements and flow statistics of increasing sophistication and capability, but what of their accuracy? And what are the measures to be used in validation? This paper argues that the issue of accuracy be addressed by cross-facility and cross-disciplinary examination of modern datasets along with increased reporting of internal quality checks in PIV analysis. Further, it is argued that the appropriate validation metrics for aeroacoustic applications are increasingly complicated statistics that have been shown in aeroacoustic theory to be critical to flow-generated sound.

  17. Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase

    ERIC Educational Resources Information Center

    Kulkarni, Suhasini; Tran, Vu; Ho, Maggie K.-M.; Phan, Chieu; Chin, Elizabeth; Wemmer, Zeke; Sommerhalter, Monika

    2010-01-01

    This experiment was performed in an upper-level undergraduate biochemistry laboratory course. Students learned how to immobilize an enzyme in a sol-gel matrix and how to perform and evaluate enzyme-activity measurements. The enzyme acid phosphatase (APase) from wheat germ was encapsulated in sol-gel beads that were prepared from the precursor…

  18. Spirit View of Phobos Eclipse, Sol 675

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Spirit View of Phobos Eclipse, Sol 675

    NASA's Mars Exploration Rover Spirit observed the Martian moon Phobos entering the shadow of Mars during the night of the rover's 675th sol (Nov. 27, 2005). The panoramic camera captured 16 images, spaced 10 seconds apart, covering the period from when Phobos was in full sunlight to when it was entirely in shadow. As with our own Moon during lunar eclipses on Earth, even when in the planet's shadow, Phobos was not entirely dark. The small amount of light still visible from Phobos is a kind of 'Mars-shine' -- sunlight reflected through Mars' atmosphere and into the shadowed region.

    This view is a time-lapse composite of images taken 20 seconds apart, showing the movement of Phobos from left to right. (At 10 seconds apart, the images of the moon overlap each other.) Scientists are using information about the precise timing of Martian moon eclipses gained from observations such as these to refine calculations about the orbital path of Phobos. The precise position of Phobos will be important to any future spacecraft taking detailed pictures of the moon or landing on its surface.

  19. SOL Reflectometer for Alcator C-Mod

    SciTech Connect

    Hanson, Gregory R; Wilgen, John B; Wukitch, Dr. Steve; Lin, Dr. Yijun; Lau, Cornwall H; Wallace, Gregory M

    2008-01-01

    A two-frequency x-mode reflectometer operating from 100 146 GHz is being deployed on Alcator C-Mod to measure the density profile and fluctuations in the scrape-off layer (SOL) immediately in-front of the new J-port ICRF antenna and the new B-port Lower Hybrid launcher. The reflectometer will cover densities from 1016 to 1020 m-3 at 5 5.4 T. To provide the greatest flexibility and capability to deal with density fluctuations approaching 100% peak to peak in the SOL, both full-phase and differential-phase measurement capabilities with sweep speeds of ~10 s to >1 ms are being implemented. The differential-phase measurement will use a difference-frequency of 500 MHz, corresponding to cutoff layer separations ranging from about 0.1 mm to 1 mm. The reflectometer will have 6 sets of launchers: 3 on the J-port ICRF antenna and 3 on the B-port LHRF launcher. The ICRF and LHRF antennas will incorporate reflectometer antennas at their top, bottom and mid-plane locations.

  20. Opportunity's Sol 446 Position, with Relative Heights

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Coding for Information About Relative Elevations This mosaic of navigation-camera frames from NASA's Mars Exploration Rover Opportunity, presented in a vertical projection, shows the rover's position after it dug itself to wheel-hub depth in a small dune during its 446th martian day, or sol (April 26, 2005). In figure 1, the colors are coding for information about relative elevations in the surrounding area. Red areas are the highest in the image, green areas the lowest. The difference between red and green is about 70 centimeters (28 inches).

    The elongated dune, or ripple, is about one-third of a meter (one foot) tall and 2.5 meters (8 feet) wide.

    Opportunity had completed nearly 40 meters (131 feet) of a planned 90-meter (295-foot) drive that sol when its wheels began slipping. The rover was driving backwards at the time. The rover team frequently alternates between backwards and forwards driving to keep wheel lubrication well distributed. The wheels kept rotating enough times to have covered the rest of the distance if they hadn't been slipping, but the rover eventually barely inched forward. After a turn at the end of the planned drive, Opportunity sensed that it had not turned properly and stopped moving.

    The rover team spent more than a week designing and conducting tests under simulated Mars conditions on Earth before choosing the best way for Opportunity to drive out of the dune.

  1. Opportunity's Surroundings After Sol 1820 Drive (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11841 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11841

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009).

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  2. After Sample-Delivery Attempt, Sol 62

    NASA Technical Reports Server (NTRS)

    2008-01-01

    NASA's Phoenix Mars Lander collected a soil sample and attempted to deliver some of it to a laboratory oven on the deck during the mission's 62nd Martian day, or sol, (July 28, 2008). The sample came from a hard layer at the bottom of the 'Snow White' trench and might have contained water ice mixed with the soil. This image taken after the attempt to deliver the sample through the open doors to cell number zero on the Thermal and Evolved-Gas Analyzer shows that very little of the soil fell onto the screened opening.

    Not enough material reached the oven, through a funnel under the screen, to proceed with analysis of the sample material.

    Phoenix's Robotic Arm Camera took this image at 7:54 a.m. local solar time on Sol 62. The size of the screened opening is about 10 centimeters (4 inches) long by 4 centimeters (1.5 inches) wide.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  3. Opportunity's Surroundings on Sol 1798 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11850 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11850

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  4. View Ahead After Spirit's Sol 1861 Drive

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009).

    The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right.

    The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate.

    In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called 'Tsiolkovsky' and is about 40 meters (about 130 feet) from the rover's position.

    This view is presented as a cylindrical projection with geometric seam correction.

  5. Spirit Beside 'Home Plate,' Sol 1809 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11803 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11803

    NASA Mars Exploration Rover Spirit used its navigation camera to take the images assembled into this stereo, 120-degree view southward after a short drive during the 1,809th Martian day, or sol, of Spirit's mission on the surface of Mars (February 3, 2009).

    By combining images from the left-eye and right-eye sides of the navigation camera, the view appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    Spirit had driven about 2.6 meters (8.5 feet) that sol, continuing a clockwise route around a low plateau called 'Home Plate.' In this image, the rocks visible above the rovers' solar panels are on the slope at the northern edge of Home Plate.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  6. Opportunity's Surroundings on Sol 1818 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11846 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11846

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view.

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  7. Phoenix Telltale Movie with Clouds, Sol 103

    NASA Technical Reports Server (NTRS)

    2008-01-01

    NASA's Phoenix Mars Lander's telltale catches a breeze as clouds move over the landing site on Sol 103 (Sept. 7, 2008), the 103rd Martian day since landing.

    Phoenix's Surface Stereo Imager took this series of images during daily telltale monitoring around 3 p.m. local solar time and captured the clouds moving over the landing site.

    Phoenix can measure wind speed and direction by imaging the telltale, which is about about 10 centimeters (4 inches) tall. The telltale was built by the University of Aarhus, Denmark.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. SUSY Les Houches Accord 2

    SciTech Connect

    Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D.; Desch, K.; Ellwanger, U.; Gambino, P.; Godbole, R.; Goto, T.; /Cambridge U., DAMTP /Monash U. /Annecy, LAPTH /Bonn U. /Harish-Chandra Res. Inst. /Orsay, LPT /Turin U. /INFN, Turin /Bangalore, Indian Inst. Sci. /KEK, Tsukuba /Barcelona U.

    2007-11-08

    The Supersymmetry Les Houches Accord (SLHA) [1] provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.

  9. SUSY Les Houches Accord 2

    SciTech Connect

    Allanach, B.; Balazs, C.; Belanger, G.; Bernhardt, M.; Boudjema, F.; Choudhury, D.; Desch, K.; Ellwanger, U.; Gambino, P.; Godbole, R.; Goto, T.; Guasch, J.; Guchait, M.; Hahn, T.; Heinemeyer, S.; Hugonie, C.; Hurth, T.; Kraml, S.; Kreiss, S.; Lykken, J.; Moortgat, F.; /Cambridge U., DAMTP /Monash U. /Annecy, LAPTH /Bonn U. /Harish-Chandra Res. Inst. /Orsay, LPT /Turin U. /INFN, Turin /Bangalore, Indian Inst. Sci. /KEK, Tsukuba /Barcelona U. /Tata Inst. /Munich, Max Planck Inst. /Cantabria Inst. of Phys. /Montpellier U. /CERN /SLAC /Edinburgh U. /Fermilab /Zurich, ETH /Southampton U.

    2007-11-08

    The Supersymmetry Les Houches Accord (SLHA) provides a universal set of conventions for conveying spectral and decay information for supersymmetry analysis problems in high energy physics. Here, we propose extensions of the conventions of the first SLHA to include various generalizations: the minimal supersymmetric standard model with violation of CP, R-parity, and flavor, as well as the simplest next-to-minimal model.

  10. Martian Arctic Dust Devil, Phoenix Sol 104

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander caught this dust devil in action west-southwest of the lander at 11:16 a.m. local Mars time on Sol 104, or the 104th Martian day of the mission, Sept. 9, 2008.

    Dust devils have not been detected in any Phoenix images from earlier in the mission, but at least six were observed in a dozen images taken on Sol 104.

    Dust devils are whirlwinds that often occur when the Sun heats the surface of Mars, or some areas on Earth. The warmed surface heats the layer of atmosphere closest to it, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado.

    The dust devil visible in the center of this image just below the horizon is estimated to be about 400 meters (about 1,300 feet) from Phoenix, and 4 meters (13 feet) in diameter. It is much smaller than dust devils that have been observed by NASA's Mars Exploration Rover Spirit much closer to the equator. It is closer in size to dust devils seen from orbit in the Phoenix landing region, though still smaller than those.

    The image has been enhanced to make the dust devil easier to see.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  11. Appendicite chronique chez les enfants

    PubMed Central

    Kim, David; Butterworth, Sonia A.; Goldman, Ran D.

    2016-01-01

    Résumé Question Alors que le diagnostic d’appendicite aigu est relativement simple à poser, celui d’appendicite chronique peut être controversé et souvent mal posé. De quelle manière et à quel moment les cliniciens devraient-ils investiguer l’appendicite chronique comme la cause de douleurs abdominales chroniques et récidivantes dans la population pédiatrique? Réponse L’appendicite chronique est une inflammation ou fibrose de longue date de l’appendice dont le tableau clinique est une douleur abdominale prolongée ou intermittente. Son diagnostic est souvent difficile à poser et elle peut entraîner des complications telles que des infections intra-abdominales, ou l’occlusion ou la perforation de l’intestin. Le tableau clinique, de même que les études d’imagerie, peuvent aider le clinicien à écarter d’autres affections, et chez les patients qui reçoivent un diagnostic, dont de nombreux enfants, l’appendicectomie soulage partiellement ou complètement la douleur.

  12. Silica scintillating materials prepared by sol-gel methods

    SciTech Connect

    Werst, D.W.; Sauer, M.C. Jr.; Cromack, K.R.; Lin, Y.; Tartakovsky, E.A.; Trifunac, A.D.

    1993-12-31

    Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons.

  13. Molecular host sol-gel films for chemical sensing applications

    SciTech Connect

    Shi, J.; Johnson, S.; Yang, X.; Swanson, B.

    1997-12-31

    Sol-gel cyclodextrin coatings on surface acoustic wave (SAW) device as VOC sensors have been studied. The sol-gel approach to thin films efficiently yields uniform coatings on SAW devices. The films were characterized by ATR-FT-IR, ellipsometry and SEM. The incorporation of molecular host reagents (cyclodextins and their derivatives) into thin films greatly enhance the sensitivity and selectivity of SAW sensors. It is believed that molecular recognition (selective sorption) occurs at the gas-solid interface. From the SAW data, it is possible to calculate the binding constants of sol-gel films towards a variety VOCs. The identification of VOCs based on SAW sensor arrays is discussed.

  14. Sol-gel derived PZT films doped with vanadium pentoxide

    SciTech Connect

    Shen Hongfang; Guo Qing; Zhao Zhiman; Cao Guozhong

    2009-11-15

    The present research investigated the sol-gel preparation, dielectric and ferroelectric properties of PZT films doped with 5 mol% vanadium oxide. Stable PZTV sols can be readily formed, and homogeneous, micrometer thick and pinhole-free PZTV films were obtained by using spin coating followed with rapid annealing. The X-ray diffraction patterns revealed that no parasitic or secondary phases were formed in the sol-gel PZT films with the addition of vanadium oxide. The material doped with vanadium pentoxide showed enhanced dielectric constant and remanent polarization with reduced loss tangent and coercive field.

  15. Effect of Chelating Agents on the Stability of Nano-TiO2 Sol Particles for Sol-Gel Coating.

    PubMed

    Maeng, Wan Young; Yoo, Mi

    2015-11-01

    Agglomeration of sol particles in a titanium alkoxide (tetrabutyl orthotitanate (TBOT), > 97%) solution during the hydrolysis and condensation steps makes the sol solution difficult to use for synthesizing homogeneous sol-gel coating. Here, we have investigated the effect of stabilizing agents (acetic acid and ethyl acetoacetate (EAcAc)) on the agglomeration of Ti alkoxide particles during hydrolysis and condensation in order to determine the optimized conditions for controlling the precipitation of TiO2 particles. The study was conducted at R(AC) ([acetic acid]/[TBOT]) = 0.1-5 and R(EAcAc)([EAcAc]/[TBOT]) = 0.05-0.65. We also studied the effects of a basic catalyst ethanolamine (ETA), water, and HCl on sol stability. The chelating ligands in the precursor sol were analyzed with FT-IR. The coating properties were examined by focused ion beam. The stabilizing agents (acetic acid and EAcAc) significantly influenced the agglomeration and precipitation of TBOT precursor particles during hydrolysis. As R(AC) and R(EAcAc) increased, the agglomeration remarkably decreased. The stability of the sol with acetic acid and EAcAc arises from the coordination of the chelating ligand to TBOT that hinders hydrolysis and condensation. A uniform fine coating (thickness: 30 nm) on stainless steel was obtained by using an optimized sol with R(AC) = 0.5 and R(EAcAc) = 0.65. PMID:26726529

  16. Les etoiles qui ne veulent pas vieillir

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.

    1995-12-01

    Qu'est-ce qui fait courir Jean-Claude Pecker ? Ses travaux sur les atmospheres stellaires qu'il poursuit aujourd'hui ? Son combat pour les droits de l'homme, ou contre le sceau du secret qui pese encore sur la recherche fondamentale ? Tout a la fois. Pour cette figure emblematique de l'astrophysique francaise, aujourd'hui a la retraite, pas question de raccrocher les armes...

  17. La détermination des distances: Sol, Hipparcos, GAIA.

    NASA Astrophysics Data System (ADS)

    Turon, C.

    Les parallaxes trigonométriques des étoiles les plus proches du soleil sont la base de la détermination des distances dans l'Univers. Elles permettent, par la calibration en luminosité des différents indicateurs de distance d'étalonner les distances d'abord dans notre Galaxie, puis dans les galaxies du Groupe Local, puis pour les galaxies plus lointaines. Cette base est, actuellement, très mince, et peu de types d'étoiles y sont représentés. Hipparcos va déjà apporter une amélioration sensible. Avec GAIA une révision complète des calibrations de luminosité de tous les indicateurs "primaires" serait directement possible.

  18. Sol gel processes. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning the development and utilization of sol-gel processes and techniques. Topics include antireflective coatings, studies of sol-gel transitions, sol-gel synthesis and polymerization, sol-gel derived thin films and glasses, and sol-gel production of microspheres. Applications in nuclear waste management, nuclear fuel manufacturing, glass optical waveguide development, and solar energy collection are presented. (Contains 250 citations and includes a subject term index and title list.)

  19. Effects of Cell Windows on TwinSol Beams

    NASA Astrophysics Data System (ADS)

    Cushman, Kimmy

    2016-04-01

    In order to study reactions with unstable nuclei, radioactive-ion beams must be used. One method for producing radioactive beams is the TwinSol experimental setup at the University of Notre Dame. At TwinSol, stable and unstable isotope beams bombard a gas target, where one atmosphere of gas must be confined from the surrounding vacuum. Thin foil windows are used to contain the gas in the cell. In order to optimize the quality of secondary beams from TwinSol, it is necessary to understand and minimize the effects of energy loss and straggling in the windows. This work is the beginning of a process to improve the TwinSol design so that secondary beams produced with heavier ions such as Oxygen, Fluorine, and Neon can be pursued.

  20. Production of continuous mullite fiber via sol-gel processing

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Sparks, J. Scott; Esker, David C.

    1990-01-01

    The development of a continuous ceramic fiber which could be used in rocket engine and rocket boosters applications was investigated at the Marshall Space Flight Center. Methods of ceramic fiber production such as melt spinning, chemical vapor deposition, and precursor polymeric fiber decomposition are discussed and compared with sol-gel processing. The production of ceramics via the sol-gel method consists of two steps, hydrolysis and polycondensation, to form the preceramic, followed by consolidation into the glass or ceramic structure. The advantages of the sol-gel method include better homogeneity and purity, lower preparation temperature, and the ability to form unique compositions. The disadvantages are the high cost of raw materials, large shrinkage during drying and firing which can lead to cracks, and long processing times. Preparation procedures for aluminosilicate sol-gel and for continuous mullite fibers are described.

  1. Organofunctional Sol-Gel Materials for Toxic Metal Separation

    SciTech Connect

    Im, Hee-Jung; Yost, Terry L.; Yang, Yihui; Bramlett, J. Morris; Yu, Xiang-Hua; Fagan, Bryan C.; Allain, Leonardo R.; Chen, Tianniu; Xue, Ziling; Barnes, Craig E.; Dai, Sheng; Rocker, Lee E.; Sepaniak, Michael J.

    2003-09-10

    Inorganic-organic silica sol-gels grafted or encapsulated with organic ligands were prepared and found to selectively and reversibly remove target metal ions such as Cu2+, Cd2+, and Sr2+. These organofunctional sol-gel materials, which were easily prepared from off-the-shelf chemicals, were hydrophilic and showed fast kinetics of metal uptake. The sol-gels were easily regenerated and used in multi-cycle metal removal. In our search for new ligands for metal removal, we found that the reactions of thioacetal ligands with Hg2+ gave Hg(SCH2COOH)2. Our studies of organofunctional sol-gel materials for metal separation will be discussed.

  2. New developments for sol-gel film and fiber processing

    SciTech Connect

    Hurd, A.J.

    1995-03-01

    New insights into the development of microstructure in sol-gel films have recently been revealed by several diagnostic techniques, including imaging ellipsometry, {open_quotes}chemical imaging{close_quotes} by fluorescent tracers, light scattering from capillary waves, and finite-element modeling. The evolution of porosity during the continuous transition from dilute sol to porous solid in restricted geometries such as films and fibers is becoming clearer through fundamental understanding of evaporation dynamics and capillarity.

  3. Martian Dust Devil Movie, Phoenix Sol 104

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander caught this dust devil in action west of the lander in four frames shot about 50 seconds apart from each other between 11:53 a.m. and 11:56 a.m. local Mars time on Sol 104, or the 104th Martian day of the mission, Sept. 9, 2008.

    Dust devils have not been detected in any Phoenix images from earlier in the mission, but at least six were observed in a dozen images taken on Sol 104.

    Dust devils are whirlwinds that often occur when the Sun heats the surface of Mars, or some areas on Earth. The warmed surface heats the layer of atmosphere closest to it, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado.

    The dust devil visible in this sequence was about 1,000 meters (about 3,300 feet) from the lander when the first frame was taken, and had moved to about 1,700 meters (about 5,600 feet) away by the time the last frame was taken about two and a half minutes later. The dust devil was moving westward at an estimated speed of 5 meters per second (11 miles per hour), which is similar to typical late-morning wind speed and direction indicated by the telltale wind gauge on Phoenix.

    This dust devil is about 5 meters (16 feet) in diameter. This is much smaller than dust devils that have been observed by NASA's Mars Exploration Rover Spirit much closer to the equator. It is closer in size to dust devils seen from orbit in the Phoenix landing region, though still smaller than those..

    The image has been enhanced to make the dust devil easier to see. Some of the frame-to-frame differences in the appearance of foreground rocks is because each frame was taken through a different color filter.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. New Record Five-Wheel Drive, Spirit's Sol 1856

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,856th Martian day, or sol, of Spirit's surface mission (March 23, 2009). The center of the view is toward the west-southwest.

    The rover had driven 25.82 meters (84.7 feet) west-northwestward earlier on Sol 1856. This is the longest drive on Mars so far by a rover using only five wheels. Spirit lost the use of its right-front wheel in March 2006. Before Sol 1856, the farthest Spirit had covered in a single sol's five-wheel drive was 24.83 meters (81.5 feet), on Sol 1363 (Nov. 3, 2007).

    The Sol 1856 drive made progress on a route planned for taking Spirit around the western side of the low plateau called 'Home Plate.' A portion of the northwestern edge of Home Plate is prominent in the left quarter of this image, toward the south.

    This view is presented as a cylindrical projection with geometric seam correction.

  5. Spirit Movie of Phobos Eclipse, Sol 675

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Spirit Phobos Eclipse Animation

    NASA's Mars Exploration Rover Spirit observed the Martian moon Phobos entering the shadow of Mars during the night of the rover's 675th sol (Nov. 27, 2005). The panoramic camera captured 16 images, spaced 10 seconds apart, covering the period from when Phobos was in full sunlight to when it was entirely in shadow. As with our own Moon during lunar eclipses on Earth, even when in the planet's shadow, Phobos was not entirely dark. The small amount of light still visible from Phobos is a kind of 'Mars-shine' -- sunlight reflected through Mars' atmosphere and into the shadowed region.

    This clip is a sequence of the 16 images showing the eclipse at about 10 times normal speed. It shows the movement of Phobos from left to right as the moon enters the shadow. Scientists are using information about the precise timing of Martian moon eclipses gained from observations such as these to refine calculations about the orbital path of Phobos. The precise position of Phobos will be important to any future spacecraft taking detailed pictures of the moon or landing on its surface.

  6. Dust Devils at Gusev, Sol 525

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows several dust devils moving across the plain inside Mars' Gusev Crater. It consists of frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 525th martian day, or sol (June 25, 2005).

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks. In this clip, contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust moved by wind. The total time elapsed during the taking of these frames was 12 minutes, 25 seconds.

  7. Dust Devils at Gusev, Sol 537

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows some distant dust devils and one closer one blowing across the floor of Mars' Gusev Crater. It consists of frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 537th martian day, or sol (July 7, 2005).

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.

    In this clip, contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust moved by wind. The total time elapsed during the taking of these frames was 13 minutes, 46 seconds.

  8. Sol 568 Dust Devil in Gusev, Unenhanced

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows several dust devils moving from right to left across a plain inside Mars' Gusev Crater, as seen from the vantage point of NASA's Mars Exploration Rover Spirit in hills rising from the plain. The clip consists of frames taken by Spirit's navigation camera during the rover's 543rd martian day, or sol (July 13, 2005). Unlike some other movie clips of dust devils seen by Spirit, the images in this clip have not been processed to enhance contrast of the dust devils. The total time elapsed during the taking of these frames was 12 minutes, 17 seconds.

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.

  9. Sol Duc Hot Springs feasibility study

    SciTech Connect

    Not Available

    1981-12-01

    Sol Duc Springs is located in the Olympic National Park in western Washington state. Since the turn of the century, the area has served as a resort, offering hot mineral baths, lodge and overnight cabin accommodations. The Park Service, in conjunction with the concessionaire, is in the process of renovating the existing facilities, most of which are approximately 50 years old. The present renovation work consists of removing all of the existing cabins and replacing them with 36 new units. In addition, a new hot pool is planned to replace the existing one. This report explores the possibility of a more efficient use of the geothermal resource to accompany other planned improvements. It is important to note that the system outlined is based upon the resource development as it exists currently. That is, the geothermal source is considered to be: the two existing wells and the hot springs currently in use. In addition, every effort has been made to accommodate the priorities for utilization as set forth by the Park Service.

  10. Dust Devils in Gusev Crater, Sol 463

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 463rd martian day, or sol (April 22, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  11. Dust Devil in Gusev Crater, Sol 445

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a single dust devil -- a whirlwind that lofts dust into the air -- about 2 kilometers (1 mile) away, moving across a plain inside Mars' Gusev Crater for several minutes. The dust devil appears in 21 frames. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. The navigation camera on NASA's Mars Exploration Rover Spirit took these images on the rover's 445th martian day, or sol (April 14, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  12. Large Dust Devil on Horizon, Sol 468

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a large, distant dust devil -- a whirlwind that lofts dust into the air -- as a dark shape on the horizon near the right side of the images. This dust devil was about 5 kilometers (3 miles) away from NASA's Mars Exploration Rover Spirit, and may have been up to 200 meters or yards in diameter. Smaller dust devils closer to the rover appear bright against the dark ground. Spirit's navigation camera took these images on the rover's 468th martian day, or sol (April 27, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  13. Electrophoretic Porosimetry of Sol-Gels

    NASA Technical Reports Server (NTRS)

    Snow, L. A.; Smith, D. D.; Sibille, L.; Hunt, A. J.; Ng, J.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    It has been hypothesized that gravity has an effect on the formation and resulting microstructure of sol-gels. In order to more clearly resolve the effect of gravity, pores may be non-destructively analyzed in the wet gel, circumventing the shrinkage and coarsening associated with the drying procedure. We discuss the development of an electrophoretic technique, analogous to affinity chromatography, for the determination of pore size distribution and its application to silica gels. Specifically a monodisperse charged dye is monitored by an optical densitometer as it moves through the wet gel under the influence of an electric field. The transmittance data (output) represents the convolution of the dye concentration profile at the beginning of the run (input) with the pore size distribution (transfer function), i.e. linear systems theory applies. Because of the practical difficulty in producing a delta function input dye profile we prefer instead to use a step function. Average pore size is then related to the velocity of this dye front, while the pore size distribution is related to the spreading of the front. Preliminary results of this electrophoretic porosimetry and its application to ground and space-grown samples will be discussed.

  14. Bell-shaped sol-gel-sol conversions in pH-responsive worm-based nanostructured fluid.

    PubMed

    Zhang, Yongmin; An, Pengyun; Liu, Xuefeng

    2015-03-21

    A pH-switchable worm system was fabricated by simply mixing two non-surface-active compounds, N-(3-(dimethylamino)propyl)palmitamide (PMA) and citric acid (HCA), at a molar ratio of 3 : 1. Such a nanostructured fluid exhibits bell-shaped sol-gel-sol transitions with sequential pH variation, reflecting continuous structural transformations from sphere to worm to no aggregates. PMID:25675411

  15. Slow Release of Plant Volatiles Using Sol-Gel Dispensers.

    PubMed

    Bian, L; Sun, X L; Cai, X M; Chen, Z M

    2014-12-01

    The black citrus aphid, also known as the tea aphid, (Toxoptera aurantii Boyer) attacks economically important crops, including tea (Camellia sinensis (L.) O. Kuntze). In the current study, silica sol-gel formulations were screened to find one that could carry and release C. sinensis plant volatiles to lure black citrus aphids in a greenhouse. The common plant volatile trans-2-hexen-1-al was used as a model molecule to screen for suitable sol-gel formulations. A zNose (Electronic Sensor Technology, Newbury Park, CA) transportable gas chromatograph was used to continuously monitor the volatile emissions. A sol-gel formulation containing tetramethyl orthosilicate and methyltrimethoxysilane in an 8:2 (vol:vol) ratio was selected to develop a slow-release dispenser. The half-life of trans-2-hexen-1-al in the sol-gel dispenser increased slightly with the volume of this compound in the dispenser. Ten different volatiles were tested in the sol-gel dispenser. Alcohols of 6-10 carbons had the longest half-lives (3.01-3.77 d), while esters of 6-12 carbons had the shortest (1.53-2.28 d). Release of these volatiles from the dispensers could not be detected by the zNose after 16 d (cis-3-hexenyl acetate) to 26 d (3,7-dimethylocta-1,6-dien-3-ol). In greenhouse experiments, trans-2-hexen-1-al and cis-3-hexen-1-ol released from the sol-gel dispensers attracted aphids for ≍17 d, and release of these volatiles could not be detected by the zNose after ≍24 d. The sol-gel dispensers performed adequately for the slow release of plant volatiles to trap aphids in the greenhouse. PMID:26470065

  16. Sol-gel encapsulation for controlled drug release and biosensing

    NASA Astrophysics Data System (ADS)

    Fang, Jonathan

    The main focus of this dissertation is to investigate the use of sol-gel encapsulation of biomolecules for controlled drug release and biosensing. Controlled drug release has advantages over conventional therapies in that it maintains a constant, therapeutic drug level in the body for prolonged periods of time. The anti-hypertensive drug Captopril was encapsulated in sol-gel materials of various forms, such as silica xerogels and nanoparticles. The primary objective was to show that sol-gel silica materials are promising drug carriers for controlled release by releasing Captopril at a release rate that is within a therapeutic range. We were able to demonstrate desired release for over a week from Captopril-doped silica xerogels and overall release from Captopril-doped silica nanoparticles. As an aside, the antibiotic Vancomycin was also encapsulated in these porous silica nanoparticles and desired release was obtained for several days in-vitro. The second part of the dissertation focuses on immobilizing antibodies and proteins in sol-gel to detect various analytes, such as hormones and amino acids. Sol-gel competitive immunoassays on antibody-doped silica xerogels were used for hormone detection. Calibration for insulin and C-peptide in standard solutions was obtained in the nM range. In addition, NASA-Ames is also interested in developing a reagentless biosensor using bacterial periplasmic binding proteins (bPBPs) to detect specific biomarkers, such as amino acids and phosphate. These bPBPs were doubly labeled with two different fluorophores and encapsulated in silica xerogels. Ligand-binding experiments were performed on the bPBPs in solution and in sol-gel. Ligand-binding was monitored by fluorescence resonance energy transfer (FRET) between the two fluorophores on the bPBP. Titration data show that one bPBP has retained its ligand-binding properties in sol-gel.

  17. The Sol project: the sun in time

    NASA Astrophysics Data System (ADS)

    Pinho, L. G. F.; Porto de Mello, G. F.; de Medeiros, J. R.; Do Nascimento, J. D., Jr.; da Silva, L.

    2003-08-01

    The solar place in the set of stellar properties of the neighborhood, such as chemical composition, magnetic activity, lithium depletion, and others, suggests that the Sun may not exactly be a representative star. A few of the solar putative peculiarities seem to involve details of its evolutionary history, and that some light might be shed onto this question by a new approach based on the analysis of a time line in the HR diagram, searching for stars that might represent past, present and future solar evolutionary loci. The SOL Project (Solar Origin and Life) aims towards the identification, among the nearby stars, of those that share in detail the solar evolutionary track, in order to put the Sun as a star in proper perspective. We aim at obtaining, spectroscopically, atmospheric parameters, Fe and Li abundances, space velocities, state of evolution, degree of chromospheric activity and rotational velocities of a stellar sample, selected from precise astrometry and photometry of the Hipparcos catalogue, as to represent the Sun in various evolutionary stages along the solar mass, solar metallicity theoretical track: the early Sun, the present Sun, the subgiant Sun and the giant Sun. Here we present a progress report of the survey: the sample selection, OPD spectroscopic observations and preliminary results of the atmospheric parameters and evolutionary status analysis. As a by-product, we also present a new effective temperature calibration, based on published Infrared Flux Method data, and calibrated explicitly for precise spectroscopic stellar metallicities, for the (B-V), (BT-VT), (R-I), (V-I), (V-R) and (V-K) color indices, and valid for cool, normal and moderately metal-poor giant stars.

  18. Optical spectroscopy of trivalent chromium in sol-gel lithium niobate

    SciTech Connect

    Krebs, J.K.; Happek, U.

    2005-12-19

    We report on the characterization of sol-gel derived lithium niobate via trivalent chromium probe ions, a study that is motivated by recent reports on the synthesis of high quality sol-gel lithium niobate (LiNbO{sub 3}). In order to assess the quality of sol-gel derived LiNbO{sub 3}, we incorporate Cr{sup 3+} during the hydrolysis stage of the sol-gel process. A comparison of the Cr{sup 3+} emission and photoexcitation data on both sol-gel and melt-grown LiNbO{sub 3} shows that the sol-gel derived material is highly stoichiometric.

  19. Impurity control studies using SOL flow in DIII-D

    SciTech Connect

    Wade, M.R.; Hogan, J.T.; Isler, R.C.

    1998-11-01

    Experiments on DIII-D have demonstrated the efficacy of using induced scrape-off-layer (SOL) flow to preferentially enrich impurities in the divertor plasma. This SOL flow is produced through simultaneous deuterium gas injection at the midplane and divertor exhaust. Using this SOL flow, an improvement in enrichment (defined as the ratio of impurity fraction in the divertor to that in the plasma core) has been observed for all impurities in trace-level experiments (i.e., impurity level is non-perturbative), with the degree of improvement increasing with impurity atomic number. In the case of argon, exhaust gas enrichment using a modest SOL flow is as high as 17. Using this induced SOL flow technique and argon injection, radiative ELMing H-mode plasmas have been produced that combine high radiation losses (P{sub rad}/P{sub input} > 70%), low core fuel dilution (Z{sub eff} < 1.9), and good core confinement ({tau}{sub E} > 1.0 {tau}{sub E},ITER93H).

  20. Fast wave power flow along SOL field lines in NSTX

    NASA Astrophysics Data System (ADS)

    Perkins, R. J.; Bell, R. E.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; Leblanc, B. P.; Kramer, G. J.; Phillips, C. K.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; Green, D. L.; McLean, A.; Maingi, R.; Ryan, P. M.; Jaeger, E. F.; Sabbagh, S.

    2012-10-01

    On NSTX, a major loss of high-harmonic fast wave (HHFW) power can occur along open field lines passing in front of the antenna over the width of the scrape-off layer (SOL). Up to 60% of the RF power can be lost and at least partially deposited in bright spirals on the divertor floor and ceiling [1,2]. The flow of HHFW power from the antenna region to the divertor is mostly aligned along the SOL magnetic field [3], which explains the pattern of heat deposition as measured with infrared (IR) cameras. By tracing field lines from the divertor back to the midplane, the IR data can be used to estimate the profile of HHFW power coupled to SOL field lines. We hypothesize that surface waves are being excited in the SOL, and these results should benchmark advanced simulations of the RF power deposition in the SOL (e.g., [4]). Minimizing this loss is critical optimal high-power long-pulse ICRF heating on ITER while guarding against excessive divertor erosion.[4pt] [1] J.C. Hosea et al., AIP Conf Proceedings 1187 (2009) 105. [0pt] [2] G. Taylor et al., Phys. Plasmas 17 (2010) 056114. [0pt] [3] R.J. Perkins et al., to appear in Phys. Rev. Lett. [0pt] [4] D.L. Green et al., Phys. Rev. Lett. 107 (2011) 145001.

  1. Structural evolution and stability of sol gel biocatalysts

    NASA Astrophysics Data System (ADS)

    Rodgers, L. E.; Knott, R. B.; Holden, P. J.; Pike, K. J.; Hanna, J. V.; Foster, L. J. R.; Bartlett, J. R.

    2006-11-01

    Immobilisation strategies for catalytic enzymes are important as they allow recovery and reuse of the biocatalysts. In this work, sol-gel matrices have been used to immobilise Candida antarctica lipase B (CALB), a commonly used industrial enzyme. The sol-gel bioencapsulate is produced through fluoride-catalysed hydrolysis of mixtures of tetramethylorthosilicate (TMOS) and methyltrimethoxysilane (MTMS) in the presence of CALB, yielding materials with controlled pore sizes and surface chemistries. Sol-gel matrices prolong the catalytic life and enhance the activity of CALB, although the molecular basis for this effect has yet to be elucidated due to the limitations of analytical techniques applied to date. Small angle neutron scattering (SANS) allows such multi-component systems to be characterised through contrast matching. In the sol-gel bioencapsulate system at the contrast match point for silica, residual scattering intensity is due to the CALB and density fluctuations in the matrix. A SANS contrast variation series found the match point for the silica matrix, both with and without enzyme present, to be around 35%. The model presented here proposes a mechanism for the interaction between CALB and the surrounding sol-gel matrix, and the observed improvement in enzyme activity and matrix strength. Essentially, the inclusion of CALB modulates silicate speciation during evolution of the inorganic network, leading to associated variations in SANS contrast. The SANS protocol developed here may be applied more generally to other encapsulated enzyme systems.

  2. Kinetics and structure of silicate sol-gels

    SciTech Connect

    Assink, R.A.; Brinker, C.J.; Kay, B.D.

    1990-01-01

    The structure of a silicate sol-gel derived material depends on the nature of its reaction kinetics. The chemical state of the silicate sol-gel is characterized by both the functional group concentrations and the distribution of the functional groups about a single silicon atom. {sup 29}Si nuclear magnetic resonance (NMR) spectroscopy provides a way to quantitatively determine these concentrations and distributions as a function of time during the reaction. During the early stages of the sol-gel reaction, the distribution of hydrolyzed species enables one to calculate the relative rates of hydrolysis. During the intermediate stages of the reaction, the rate of formation of various condensed species enables one to determine the reaction rate constants for both water-producing and alcohol-producing condensation. The chemical bonding of sol-gel derived solid materials can be determined by direct polarization NMR combined with magic angle spinning techniques. These capabilities provide a valuable tool for studying the relationships between the reaction conditions, the chemical kinetics and the resulting structure of the sol-gel derived material. 8 refs., 4 figs.

  3. Sol-gel derived ? thin films on GaAs

    NASA Astrophysics Data System (ADS)

    Arscott, S.; Smith, N.; Kurchania, R.; Milne, S. J.; Miles, R. E.

    1998-02-01

    Sol-gel derived thin films of lead zirconate titanate (PZT) have been fabricated on a platinized GaAs substrate using a propane-1,3-diol based sol-gel route. PZT can be used as the piezoelectric component in bulk acoustic wave devices for monolithic microwave integrated circuit applications. A 100 nm silicon nitride buffer layer was deposited onto the GaAs by plasma-enhanced chemical vapour deposition in order to prevent gallium and arsenic outdiffusion during film fabrication. Rapid thermal processing (RTP) techniques were employed to decompose thermally the sol-gel layer to PZT in a further effort to minimize problems of gallium and arsenic outdiffusion. Adhesion between the bottom electrode and substrate was found to improve when an intermediate titanium layer deposited between the platinum and silicon nitride was oxidized prior to deposition of the platinum electrode. A crystalline PZT film was produced on the 0268-1242/13/2/016/img9 substrate configuration by firing the sol-gel coating at 0268-1242/13/2/016/img10C for 10 s using RTP. A single deposition of sol resulted in a film having a thickness of 0268-1242/13/2/016/img11. Ferroelectric hysteresis measurements yielded average values of remanant polarization and coercive field of 0268-1242/13/2/016/img12 and 0268-1242/13/2/016/img13 respectively.

  4. Opportunity's View After Long Drive on Sol 1770

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009).

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini.

    The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a cylindrical projection with geometric seam correction.

  5. Time for a Change; Spirit's View on Sol 1843 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

    This view is presented as a vertical projection with geometric seam correction. North is at the top.

    The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

    The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

  6. Opportunity's View After Long Drive on Sol 1770 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009).

    This view is presented as a vertical projection with geometric seam correction. North is at the top.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini.

    The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

  7. Time for a Change; Spirit's View on Sol 1843

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

    The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

    The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

    This view is presented as a cylindrical projection with geometric seam correction.

  8. Time for a Change; Spirit's View on Sol 1843 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11973 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11973

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

    The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  9. Time for a Change; Spirit's View on Sol 1843 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

    This view is presented as a polar projection with geometric seam correction. North is at the top.

    The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

    The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

  10. Opportunity's View After Long Drive on Sol 1770 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009).

    This view is presented as a polar projection with geometric seam correction. North is at the top.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini.

    The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

  11. Regard sur les lazarets en terre canadienne

    PubMed Central

    Milot, Jean

    2008-01-01

    Puisant dans les nombreuses références qu’offrent les publications médicales canadiennes du milieu du XIXe siècle à nos jours, l’auteur fait découvrir l’existence de lazarets en terre canadienne, décrit l’impact de la maladie sur les conditions vie des lépreux qui y étaient confinés et en souligne les contrecoups tant sur le plan physique et psychologique que social. Il présente un bref aperçu de la maladie, ses symptômes, ses signes ainsi que ses complications oculaires et rappelle les premiers moyens thérapeutiques à base d’huile de chaulmoogra introduits dans la colonie de Tracadie vers 1901. Il illustre son propos en évoquant la vie dans les lazarets de l’île de Sheldrake (1844–1848) et de Tracadie (1848–1965) au Nouveau-Brunswick, puis dans ceux des îles D’Arcy (1891–1924) et de Bentinck (1924–1957) en Colombie-Britannique. PMID:19352451

  12. Luminescence properties of Cr-doped silica sol gel glasses

    NASA Astrophysics Data System (ADS)

    Strek, Wieslaw; Lukowiak, Edward; Deren, Przemyslaw J.; Maruszewski, K.; Trabjerg, Ib; Koepke, Czeslaw; Malashkevich, G. E.; Gaishun, Vladimir E.

    1997-11-01

    The emission of Cr-doped silica glass obtained by the sol- gel method is characterized by an orange broad band with a maximum at 610 nm. Its nature is examined by the absorption, excited state absorption, emission, excitation and lifetime measurements over a wide range of temperature and for different concentration of Cr ions. Our measurement show that in spite of fact that the absorption properties of Cr- doped silica sol-gel glass are predominantly associated with Cr4+ centers, the observed in visible range emission can be assigned neither to Cr3+ nor to Cr4+ ions. The discussion of the nature of observed emission was carried out for all possible valencies of the Cr ions. In conclusion is suggested that it may be ascribed to the transitions on the monovalent Cr1+ ion. The reducing agents occurring during the sol-gel process and leading to lowering the Cr valency are discussed.

  13. Modification of sol-gel coatings by ion implantation

    NASA Astrophysics Data System (ADS)

    Hirashima, Hiroshi; Adachi, Kenji; Imai, Hiroaki

    1994-10-01

    In order to densify and to improve the physical properties, TiO2 sol-gel films, about 100 nm in thickness, on silica glass or silicon wafer were implanted with Ar+ or B+ ions. The refractive index of the as-dried films increased and the IR absorption band of OH disappeared after Ar+ implantation. Dehydration and densification of sol-gel films were enhanced by Ar+ implantation. On the other hand, the refractive index and the thickness of the films hardly changed by B+ implantation. However, IR absorption bands attributed to B-O bond were observed after B+ implantation. This suggests that sol-gel films could be chemically modified by ion implantation with reactive ion species.

  14. Optical detection of parasitic protozoa in sol-gel matrices

    NASA Astrophysics Data System (ADS)

    Livage, Jacques; Barreau, J. Y.; Da Costa, J. M.; Desportes, I.

    1994-10-01

    Whole cell parasitic protozoa have been entrapped within sol-gel porous silica matrices. Stationary phase promastigote cells of Leishmania donovani infantum are mixed with a silica sol before gelation occurs. They remain trapped within the growing oxide network and their cellular organization appears to be well preserved. Moreover protozoa retain their antigenic properties in the porous gel. They are still able to detect parasite specific antibodies in serum samples from infected patients via an enzyme linked immunosorbent assay (ELISA). Antigen- antibody associations occurring in the gel are optically detected via the reactions of a peroxidase conjugate with ortho-phenylenediamine leading to the formation of a yellow coloration. A clear-cut difference in optical density is measured between positive and negative sera. Such an entrapment of antigenic species into porous sol-gel matrices avoids the main problems due to non specific binding and could be advantageously used in diagnostic kits.

  15. Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

    NASA Technical Reports Server (NTRS)

    Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

    2004-01-01

    An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

  16. New insights into uranium (VI) sol-gel processing

    SciTech Connect

    King, C.M.; Thompson, M.C.; Buchanan, B.R. ); King, R.B. . Dept. of Chemistry); Garber, A.R. . Dept. of Chemistry)

    1990-01-01

    Nuclear Magnetic Resonance (NMR) investigations on the Oak Ridge National Laboratory process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been extremely useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub 12}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sup 17}O NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, ((UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}){sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results will be presented to illustrate that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2} ((UO{sub 2}){sub 8} O{sub 4} (OH){sub 10}) {center dot} 8H{sub 2}O. This compound is the precursor to sintered UO{sub 2} ceramic fuel. 23 refs., 10 figs.

  17. New Record Five-Wheel Drive, Spirit's Sol 1856 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11962 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11962

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,856th Martian day, or sol, of Spirit's surface mission (March 23, 2009). The center of the view is toward the west-southwest.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 25.82 meters (84.7 feet) west-northwestward earlier on Sol 1856. This is the longest drive on Mars so far by a rover using only five wheels. Spirit lost the use of its right-front wheel in March 2006. Before Sol 1856, the farthest Spirit had covered in a single sol's five-wheel drive was 24.83 meters (81.5 feet), on Sol 1363 (Nov. 3, 2007).

    The Sol 1856 drive made progress on a route planned for taking Spirit around the western side of the low plateau called 'Home Plate.' A portion of the northwestern edge of Home Plate is prominent in the left quarter of this image, toward the south.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  18. The SOL-2/Neto auxiliary protein modulates the function of AMPA-subtype ionotropic glutamate receptors.

    PubMed

    Wang, Rui; Mellem, Jerry E; Jensen, Michael; Brockie, Penelope J; Walker, Craig S; Hoerndli, Frédéric J; Hauth, Linda; Madsen, David M; Maricq, Andres V

    2012-09-01

    The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning, and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants, and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents. PMID:22958824

  19. Spirit 360-Degree View on Sol 409 (polar)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 409th martian day, or sol (Feb. 26, 2005). Spirit had driven 2 meters (7 feet) on this sol to get in position on 'Cumberland Ridge' for looking into 'Tennessee Valley' to the east. This location is catalogued as Spirit's Site 108. Rover-wheel tracks from climbing the ridge are visible on the right. The summit of 'Husband Hill' is at the center, to the south. This view is presented in a polar projection with geometric and brightness seam correction.

  20. Spirit 360-Degree View on Sol 409 (vertical)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 409th martian day, or sol (Feb. 26, 2005). Spirit had driven 2 meters (7 feet) on this sol to get in position on 'Cumberland Ridge' for looking into 'Tennessee Valley' to the east. This location is catalogued as Spirit's Site 108. Rover-wheel tracks from climbing the ridge are visible on the right. The summit of 'Husband Hill' is at the center, to the south. This view is presented in a vertical projection with geometric and brightness seam correction.

  1. Durable hydrophobic sol-gel finishing for textiles

    NASA Astrophysics Data System (ADS)

    Vihodceva, S.; Kukle, S.; Bitenieks, J.

    2015-03-01

    The surface of cotton textile was modified to create a water-repellent finishing by depositing a modifying coatings using the sol-gel technique. Treated textiles evaluated using scanning electron microscopy, X-Ray powder diffraction (XRD). The wettability of treated fabrics was characterized by water contact angle and drop test. The results showed that the cotton textile treated with 7.5 wt.% zinc acetate dihydrate sol showed excellent hydrophobic properties, water contact angle could reach 145°C without decreasing after 50 hydrothermal treatment cycles.

  2. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  3. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  4. Identification, expression, and immuno-reactivity of Sol i 2 & Sol i 4 venom proteins of queen red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae).

    PubMed

    Lockwood, Stephanie A; Haghipour-Peasley, Jilla; Hoffman, Donald R; Deslippe, Richard J

    2012-10-01

    We report on two low-molecular weight proteins that are stored in the venom of queen red imported fire ants (Solenopsis invicta). Translated amino acid sequences identified one protein to have 74.8% identity with the Sol i 2w worker allergen, and the other protein was found to have 96/97% identity with Sol i 4.01w/4.02w worker allergens. Both Sol i 2 and Sol i 4 queen and worker proteins were expressed using pEXP1-DEST vector in SHuffle™ T7 Express lysY Escherichia coli. Proteins were expressed at significant concentrations, as opposed to the μg/ml amounts by our previous expression methods, enabling further study of these proteins. Sol i 2q protein bound weakly to human IgE, sera pooled from allergic patients, whereas Sol i 2w, Sol i 4.01w, and Sol i 4q proteins bound strongly. Despite Sol i 2w and Sol i 2q proteins having 74.8% identity, the queen protein is less immuno-reactive than the worker allergen. This finding is consistent with allergic individuals being less sensitive to queen than worker venom. PMID:22683679

  5. Accentuation récente de la vulnérabilité liée à la mobilité du trait de côte et à la salinisation des sols dans l'archipel de Kerkennah (Tunisie)

    NASA Astrophysics Data System (ADS)

    Etienne, Lucile

    2014-10-01

    L'archipel de Kerkennah, situé dans le Golfe de Gabès en Tunisie, est composé d'une dizaine de petites îles dont le relief est très plat et la lithologie meuble et fragile. Les espaces les plus bas sont occupés par des sebkhas, espaces salés et stériles. L'évolution du climat et l'élévation relative du niveau de la mer ainsi que les Évolutions importantes des modes de vie et de production locaux ont conduit à des changements majeurs dans l'occupation du sol. Dans ce contexte, cette thèse vise à comprendre l'évolution de la vulnérabilité liée à la mobilité du trait de côte et à la salinisation des sols depuis les années 1960. Des études diachroniques de photo-interprétation et télédétection ont été réalisées afin d'observer et mesurer l'évolution de l'occupation du sol, du trait de côte et de l'extension des surfaces de sebkhas. Grâce à ces études et à des relevés de terrain, il est apparu que les côtes subissent majoritairement une érosion significative (0,12m/an) et que les surfaces de sebkhas s'étendent. Ces phénomènes physiques, associés aux évolutions de l'occupation des sols et aux modes de gestion parfois peu adaptés, ont conduit à une augmentation de la vulnérabilité liée à la mobilit:é du trait de côte et à la salinisation des sols. Les résultats d'un questionnaire, proposé à 139 personnes, laissent penser que la population locale perçoit le retrait de la côte et la salinisation des sols comme étant des phénomènes préoccupants et dangereux. Ainsi le contexte local est plutôt cohérent avec des phénomènes dommageables réels et une population qui semble les connaître. Cependant, la gestion littorale dans l'archipel ne semble prendre en compte ni la vulnérabilité existante, ni la perception et les connaissances de la population locale. Même si la gestion intégrée des zones côtières est préconisée en Tunisie, elle n'est pas mise en place dans l'archipel de Kerkennah.

  6. Synthesis of phthalocyanine doped sol-gel materials

    NASA Technical Reports Server (NTRS)

    Dunn, Bruce

    1993-01-01

    The synthesis of sol-gel silica materials doped with three different types of metallophthalocyanines has been studied. Homogeneous materials of good optical quality were prepared and the first optical limiting measurements of dyes in sol-gel hosts were carried out. The properties of these solid state limiters are similar to limiters based on phthalocyanine (Pc) in solution. Sol-gel silica materials containing copper, tin and germanium phthalocyanines were investigated. The initial step in all cases was to prepare silica sols by the sonogel method using tetramethoxy silane (TMOS), HCl and distilled water. Thereafter, the synthesis depended upon the specific Pc and its solubility characteristics. Copper phthalocyanine tetrasulfonic acid tetra sodium salt (CuPc4S) is soluble in water and various doping levels (1 x 10 (exp -4) M to 1 x 10 (exp -5) M) were added to the sol. The group IV Pc's, SnPc(OSi(n-hexyl)3)2 and GePc(OSi(n-hexyl)3)2, are insoluble in water and the process was changed accordingly. In these cases, the compounds were dissolved in THF and then added to the sol. The Pc concentration in the sol was 2 x 10(exp -5)M. The samples were then aged and dried in the standard method of making xerogel monoliths. Comparative nanosecond optical limiting experiments were performed on silica xerogels that were doped with the different metallophthalocyanines. The ratio of the net excited state absorption cross section (sigma(sub e)) to the ground state cross section (sigma(sub g)) is an important figure of merit that is used to characterize these materials. By this standard the SnPc sample exhibits the best limiting for the Pc doped sol-gel materials. Its cross section ratio of 19 compares favorably with the value of 22 that was measured in toluene. The GePc materials appear to not be as useful as those containing SnPc. The GePc doped solids exhibit a higher onset energy (2.5 mj and lower cross section ratio, 7. The CuPc4S sol-gel material has a still lower cross

  7. Nanopore yttria doped zirconia membranes prepared by sol-gel method

    SciTech Connect

    Gopalan, R.; Chang, C.H.; Lin, Y.S.

    1994-12-31

    Yttria doped zirconia membranes were prepared by the sol-gel method. A solution-sol mixing method was employed to dope yttria on the grain surface of zirconia particles in the sol. These nano-structured yttria doped zirconia membranes have potential application as a support for dense oxide ceramic membranes, fuel cells and oxygen sensors.

  8. Sol-gel based oxidation catalyst and coating system using same

    NASA Technical Reports Server (NTRS)

    Watkins, Anthony N. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Patry, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor)

    2010-01-01

    An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

  9. LES versus DNS: A comparative study

    NASA Technical Reports Server (NTRS)

    Shtilman, L.; Chasnov, J. R.

    1992-01-01

    We have performed Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of forced isotropic turbulence at moderate Reynolds numbers. The subgrid scale model used in the LES is based on an eddy viscosity which adjusts instantaneously the energy spectrum of the LES to that of the DNS. The statistics of the large scales of the DNS (filtered DNS field or fDNS) are compared to that of the LES. We present results for the transfer spectra, the skewness and flatness factors of the velocity components, the PDF's of the angle between the vorticity and the eigenvectors of the rate of strain, and that between the vorticity and the vorticity stretching tensor. The above LES statistics are found to be in good agreement with those measured in the fDNS field. We further observe that in all the numerical measurements, the trend was for the LES field to be more gaussian than the fDNS field. Future research on this point is planned.

  10. Les Elements Legers: Diffusion dans les Enveloppes Stellaires et Implications Cosmologiques

    NASA Astrophysics Data System (ADS)

    Richer, Jacques

    1992-01-01

    Les observations des abondances des elements legers (Z <= 5) sont utilisees pour estimer la quantitie de lithium qui a ete produite lors du Big -Bang, et obtenir simultanement des contraintes sur la nature des inhomogeneites qui ont pu exister durant la nucleosynthese primordiale. Nous utilisons un modele simple capable de simuler approximativement la diffusion et la retro-diffusion des neutrons a travers la matiere inhomogene durant les premieres minutes de l'expansion de l'Univers. Nous tenons compte de la difference possible entre l'abondance primordiale de Li et les abondances observees dans les plus vieilles etoiles. Cette difference (un facteur 2, environ) est estimee en construisant des modeles evolutifs d'etoiles peu massives de Population II, incluant la sedimentation gravitationnelle du lithium et de l'helium. Ces modeles montrent egalement que les ages des vieux amas stellaires sont grandement surestimes lorsqu'ils sont determines a partir de modeles stellaires n'incluant pas l'effet de la diffusion de He. Nous calculons ensuite comment evoluent les abondances de Li et Be dans des etoiles plus massives et plus jeunes, de la pre-sequence principale ou de la ZAMS, jusqu'a l'epuisement de leur hydrogene central. Les modeles incluent la sedimentation simultanee de l'helium a travers l'enveloppe. Une approche hierarchique (evolution du coeur--evolution de l'enveloppe --tri des elements traces) est utilisee pour simuler efficacement le grand nombre d'etoiles necessaire pour la construction d'isochrones. Une attention particuliere est portee aux consequences de la sedimentation de He sur l'etendue des zones convectives, et sur la diffusion de Li et Be. Les forces radiatives agissant sur ces deux elements sont calculees en detail a partir des donnees atomiques. Les etoiles simulees correspondent approximativement aux types spectraux A, F, et AmFm. Les abondances de Li et Be observees dans les etoiles jeunes de ces types sont comparees a nos predictions dans le

  11. Gusev Dust Devil Movie, Sol 459 (Enhanced)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 459th martian day, or sol (April 18, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera, and the contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    The images were processed in three steps. All images were calibrated to remove known camera artifacts. The images were then processed to remove stationary objects. The result is a gray scene showing only features that change with time. The final step combined the original image with the image that shows only moving features, showing the martian scene and the enhanced dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface

  12. Gusev Dust Devil Movie, Sol 456 (Enhanced)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 456th martian day, or sol (April 15, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera, and the contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    The images were processed in three steps. All images were calibrated to remove known camera artifacts. The images were then processed to remove stationary objects. The result is a gray scene showing only features that change with time. The final step combined the original image with the image that shows only moving features, showing the martian scene and the enhanced dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface

  13. Stoichiometric hydroxyapatite obtained by precipitation and sol gel processes

    NASA Astrophysics Data System (ADS)

    Vazquez, C. G.; Barba, C. P.; Munguia, N.

    2005-06-01

    Three methods for obtaining hydroxiapatite (HA) are described. HA is a very interesting ceramic because of its many medical applications. The first two precipitation methods start from calcium and phosphorous compounds, whereas the third method is a sol-gel process that uses alcoxides. The products were characterized and compared. The observed differences are important for practical applications.

  14. Sol-Gel Matrices For Direct Colorimetric Detection Of Analytes

    DOEpatents

    Charych, Deborah H.; Sasaki, Darryl; Yamanaka, Stacey

    2002-11-26

    The present invention relates to methods and compositions for the direct detection of analytes using color changes that occur in immobilized biopolymeric material in response to selective binding of analytes to their surface. In particular, the present invention provides methods and compositions related to the encapsulation of biopolymeric material into metal oxide glass using the sol-gel method.

  15. Process of forming a sol-gel/metal hydride composite

    DOEpatents

    Congdon, James W.

    2009-03-17

    An external gelation process is described which produces granules of metal hydride particles contained within a sol-gel matrix. The resulting granules are dimensionally stable and are useful for applications such as hydrogen separation and hydrogen purification. An additional coating technique for strengthening the granules is also provided.

  16. Opportunity's View After Drive on Sol 1806 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction.

    The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a vertical projection with geometric seam correction.

  17. ARSENIC REMOVAL USING SOL-GEL SYNTHESIZED TITANIUM DIOXIDE NANOPARTICLES

    EPA Science Inventory

    In this study, the effectiveness of TiO2 nanoparticles in arsenic adsorption was examined. TiO2 particles (LS) were synthesized via sol-gel techniques and characterized for their crystallinity, surface area and pore volume. Batch adsorption studies were perf...

  18. "What D'ya Mean, Project SOL-FA?"

    ERIC Educational Resources Information Center

    Hardman, Olga S.

    1981-01-01

    Since 1977, Project Sol-fa, funded with an ESEA Title IV-C grant has provided Harrison County primary teachers with inservice training in the Kodaly method of music education. This article provides information on program funding, costs, and accomplishments. Evaluation forms and the inservice syllabus are appended. (SJL)

  19. Opportunity's View After Drive on Sol 1806 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction.

    The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a polar projection with geometric seam correction.

  20. Safe and Environmentally Acceptable Sol-gel Derived Pyrophoric Pyrotechnics

    SciTech Connect

    Simspon, R L; Satcher, J H; Gash, A

    2004-06-10

    It was demonstrated that highly porous sol-gel derived iron (III) oxide materials could be reduced to sub-micron-sized metallic iron by heating the materials to intermediate temperatures in a hydrogen atmosphere. Through a large number of experiments complete reduction of the sol-gel based materials was realized with a variety of hydrogen-based atmospheres (25-100% H{sub 2} in Ar, N{sub 2}, CO{sub 2}, or CO) at intermediate temperatures (350 C to 700 C). All of the resulting sol-gel-derived metallic iron powders were ignitable by thermal methods, however none were pyrophoric. For comparison several types of commercial micron sized iron oxides Fe2O3, and NANOCAT were also reduced under identical conditions. All resulting materials were characterized by thermal gravimetric analysis (TGA), differential thermal analysis (DTA), powder X-ray diffraction (PXRD), as well as scanning and transmission electron microscopies (SEM and TEM). In addition, the reduction of the iron oxide materials was monitored by TGA. In general the sol-gel materials were more rapidly reduced to metallic iron and the resulting iron powders had smaller particle sizes and were more easily oxidized than the metallic powders derived from the micron sized materials. The lack of pyrophoricity of the smaller fine metallic powders was unexpected and may in part be due to impurities in the materials that create a passivation layer on the iron. Several recommendations for future study directions on this project are detailed.

  1. Sol-gel matrices for direct colorimetric detection of analytes

    DOEpatents

    Charych, Deborah H.; Sasaki, Darryl; Yamanaka, Stacey

    2000-01-01

    The present invention relates to methods and compositions for the direct detection of analytes using color changes that occur in immobilized biopolymeric material in response to selective binding of analytes to their surface. In particular, the present invention provides methods and compositions related to the encapsulation of biopolymeric material into metal oxide glass using the sol-gel method.

  2. : comparison between magnetron sputtering and sol-gel synthesis

    NASA Astrophysics Data System (ADS)

    Cosentino, S.; Knebel, S.; Mirabella, S.; Gibilisco, S.; Simone, F.; Bracht, H.; Wilde, G.; Terrasi, A.

    2014-07-01

    SiGeO films have been produced by a sol-gel derived approach and by magnetron sputtering deposition. Post-thermal annealing of SiGeO films in forming gas or nitrogen atmosphere between 600 and 900 °C ensured the phase separation of the SiGeO films and synthesis and growth of Ge nanoclusters (NCs) embedded in SiO2. Rutherford backscattering spectrometry analysis evidenced a similar Ge concentration (~12 %), but a different Ge out-diffusion after annealing between the two types of techniques with the formation of a pure SiO2 surface layer (~30 nm thick) in sol-gel samples. The thermal evolution of Ge NCs has been followed by transmission electron microscopy and Raman analysis. In both samples, Ge NCs form with similar size increase (from ~3 up to ~7 nm) and with a concomitant amorphous to crystalline transition in the 600-800 °C temperature range. Despite a similar Ge concentration, a significant lower NCs density is observed in sol-gel samples attributed to an incomplete precipitation of Ge, which probably remains still dispersed in the matrix. The optical absorption of Ge NCs has been measured by spectrophotometry analyses. Ge NCs produced by the sol-gel method evidence an optical band gap of around 2 eV, larger than that of NCs produced by sputtering (~1.5 eV). These data are presented and discussed also considering the promising implications of a low-cost sol-gel based technique towards the fabrication of light harvesting devices based on Ge nanostructures.

  3. Opportunity's View After Long Drive on Sol 1770 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11791 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11791

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009).

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini.

    The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  4. The Sizing and Optimization Language, (SOL): Computer language for design problems

    NASA Technical Reports Server (NTRS)

    Lucas, Stephen H.; Scotti, Stephen J.

    1988-01-01

    The Sizing and Optimization Language, (SOL), a new high level, special purpose computer language was developed to expedite application of numerical optimization to design problems and to make the process less error prone. SOL utilizes the ADS optimization software and provides a clear, concise syntax for describing an optimization problem, the OPTIMIZE description, which closely parallels the mathematical description of the problem. SOL offers language statements which can be used to model a design mathematically, with subroutines or code logic, and with existing FORTRAN routines. In addition, SOL provides error checking and clear output of the optimization results. Because of these language features, SOL is best suited to model and optimize a design concept when the model consits of mathematical expressions written in SOL. For such cases, SOL's unique syntax and error checking can be fully utilized. SOL is presently available for DEC VAX/VMS systems. A SOL package is available which includes the SOL compiler, runtime library routines, and a SOL reference manual.

  5. Prise en charge de l’infection gonococcique chez les adultes et les jeunes

    PubMed Central

    Pogany, Lisa; Romanowski, Barbara; Robinson, Joan; Gale-Rowe, Margaret; Latham-Carmanico, Cathy; Weir, Christine; Wong, Tom

    2015-01-01

    Résumé Objectif Présenter des recommandations sur la prise en charge de l’infection gonococcique chez les adultes et les jeunes. Qualité des données Les recommandations thérapeutiques des lignes directrices canadiennes sur les infections transmissibles sexuellement reposent sur une recherche documentaire de même que sur des catégories de recommandations et des niveaux de qualité de données déterminés par au moins 2 évaluateurs. Les recommandations ont été revues par des pairs et sont en instance d’approbation par le groupe de travail d’experts. Message principal Les nouvelles recommandations portant sur la prise en charge de l’infection gonococcique chez les adultes et les jeunes préconisent les cultures à titre d’outil diagnostique lorsqu’elles sont pratiques, le traitement par antibiothérapie combinée (ceftriaxone associée à l’azithromycine) et le signalement sans délai de tous les cas dont le traitement a échoué aux autorités de santé publique. Conclusion Si elles sont suivies, ces nouvelles recommandations pourraient réduire l’échec thérapeutique, contribuer à une surveillance plus étroite des tendances à la résistance de Neisseria gonorrhoeae aux antibiotiques et contribuer à prévenir la transmission de gonorrhée résistante à plusieurs médicaments.

  6. Phase Transformation Behavior at Low Temperature in Hydrothermal Treatment of Stable and Unstable Titania Sol

    PubMed

    So; Park; Kim; Moon

    1997-07-15

    Nanosize titania sol was prepared from titanium tetraisopropoxide (TTIP) and conditions for the formation of stable sol were identified. As the H+/TTIP mole ratio decreased and H2O/TTIP mole ratio increased, stable sol was likely to be formed. The size and crystallinity remained unchanged after hydrothermal treatment of the stable sol at between 160 and 240°C. However, hydrothermal treatment of unstable sol produced rod-like particles and crystallinity of particles was changed from anatase to rutile. This difference in phase transformation at low hydrothermal treatment temperature was likely to be caused by the fact that stable sol remained to be stable even after hydrothermal treatment, while unstable sol had a tendency to be aggregated. PMID:9268523

  7. Investigation of SOL parameters and divertor particle flux from electric probe measurements in KSTAR

    NASA Astrophysics Data System (ADS)

    Bak, J. G.; Kim, H. S.; Bae, M. K.; Juhn, J. W.; Seo, D. C.; Bang, E. N.; Shim, S. B.; Chung, K. S.; Lee, H. J.; Hong, S. H.

    2015-08-01

    The upstream scrape-off layer (SOL) profiles and downstream particle fluxes are measured with a fast reciprocating Langmuir probe assembly (FRLPA) at the outboard mid-plane and a fixed edge Langmuir probe array (ELPA) at divertor region, respectively in the KSTAR. It is found that the SOL has a two-layer structure in the outboard wall-limited (OWL) ohmic and L-mode: a near SOL (∼5 mm zone) with a narrow feature and a far SOL with a broader profile. The near SOL width evaluated from the SOL profiles in the OWL plasmas is comparable to the scaling for the L-mode divertor plasmas in the JET and AUG. In the SOL profiles and the divertor particle flux profile during the ELMy H-modes, the characteristic e-folding lengths of electron temperature, plasma density and particle flux during an ELM phase are about two times larger than ones at the inter ELM.

  8. Morphology and texture of particles along the Spirit rover traverse from sol 450 to sol 745

    NASA Astrophysics Data System (ADS)

    Yingst, R. A.; Crumpler, L.; Farrand, W. H.; Li, R.; Cabrol, N. A.; Neakrase, L. D.

    2008-12-01

    We quantified and classified the shape, roundness, size, and texture of 935 loose surface particles along the Spirit rover traverse from sols 450-745 to assess origin, transport, and other alteration mechanisms that altered particles during and after formation. Variation in particle morphologic parameters along traverse is consistent with crossing mapped geologic unit boundaries. Texture is divided into four types: vesicular, smooth and flat-faceted, rough and flat-faceted, and very rough. Sphericity and roundness are intermediate and low, respectively, comparable to particles moved by high-energy transport or to crushed particles. This indicates intermittent, high-energy emplacement or modification of a single lithology, rather than systematic, continuous low-energy abrasion or wear over time. Comparison with particle morphology at other Mars landing sites is consistent with the hypothesis that no secondary systematic transport or wide-scale chemical alteration was active at a significant enough level to alter macromorphology. In particular, particle morphology at the Mars Pathfinder site shows stronger evidence of abrasion than along the Spirit traverse, suggesting Mars Pathfinder particles have undergone abrasion processes that particles in this study area have not. Additionally, morphology indices have correlation coefficients near zero, indicating that a fluvial transport mechanism is likely not responsible for morphology. Morphology and texture are instead related to origin and composition rather than subsequent modification. Morphology and texture support a volcanic origin, possibly without modification, but most likely altered primarily by ballistic impact, implying that the Spirit landing site and traverse may be utilized in the future as a standard site for characterization of impact-derived morphology.

  9. Sol-gel processes. January 1970-September 1989 (Citations from the NTIS data base). Report for January 1970-September 1989

    SciTech Connect

    Not Available

    1989-09-01

    This bibliography contains citations concerning the development and utilization of sol-gel processes and techniques. Topics include antireflective coatings, studies of sol-gel transitions, sol-gel synthesis and polymerization, sol-gel derived thin films and glasses, and sol-gel production of microspheres. Applications in nuclear waste management, nuclear-fuel manufacturing, glass optical waveguide development, and solar-energy collection are presented. (This updated bibliography contains 179 citations, 39 of which are new entries to the previous edition.)

  10. Sol-gel processes. January 1970-September 1988 (Citations from the NTIS database). Report for January 1970-September 1988

    SciTech Connect

    Not Available

    1988-09-01

    This bibliography contains citations concerning the development and utilization of sol-gel processes and techniques. Topics include antireflective coatings, studies of sol-gel transitions, sol-gel synthesis and polymerization, sol-gel derived thin films and glasses, and sol-gel production of microspheres. Applications in nuclear waste management, nuclear fuel manufacturing, glass optical waveguide development, and solar energy collection are presented. (This updated bibliography contains 140 citations, 28 of which are new entries to the previous edition.)

  11. Les origines de l'astronomie chinoise

    NASA Astrophysics Data System (ADS)

    de Saussure, Léopold; Ferrand, Preface by Gabriel

    2015-05-01

    Préface; Le texte astronomique du Yao-Tien; 1. L'origine des 'sieou'; 2. Les cinq palais célestes; 3. La série quinaire et ses dérivés; 4. La série des douze 'tche'; 5. Le cycle des douze animaux; 6. La règle des 'cho-t'i'; 7. Le cycle de Jupiter; 8. Le cycle de Jupiter (suite); 9. Les anciennes étoiles polaires; 10. Le zodiaque lunaire.

  12. Calcium and SOL Protease Mediate Temperature Resetting of Circadian Clocks

    PubMed Central

    Tataroglu, Ozgur; Zhao, Xiaohu; Busza, Ania; Ling, Jinli; O’Neill, John S.; Emery, Patrick

    2015-01-01

    Summary Circadian clocks integrate light and temperature input to remain synchronized with the day/night cycle. Although light input to the clock is well studied, the molecular mechanisms by which circadian clocks respond to temperature remain poorly understood. We found that temperature phase shifts Drosophila circadian clocks through degradation of the pacemaker protein TIM. This degradation is mechanistically distinct from photic CRY-dependent TIM degradation. Thermal TIM degradation is triggered by cytosolic calcium increase and CALMODULIN binding to TIM and is mediated by the atypical calpain protease SOL. This thermal input pathway and CRY-dependent light input thus converge on TIM, providing a molecular mechanism for the integration of circadian light and temperature inputs. Mammals use body temperature cycles to keep peripheral clocks synchronized with their brain pacemaker. Interestingly, downregulating the mammalian SOL homolog SOLH blocks thermal mPER2 degradation and phase shifts. Thus, we propose that circadian thermosensation in insects and mammals share common principles. PMID:26590423

  13. Nanoparticle metrology in sol-gels using multiphoton excited fluorescence

    NASA Astrophysics Data System (ADS)

    Karolin, J.; Geddes, C. D.; Wynne, K.; Birch, D. J. S.

    2002-01-01

    We have developed a method of measuring the growth of nanoparticles during sol-gel glass formation based on labelling the particle with a fluorescent dye and determining the multiphoton excited decay of fluorescence anisotropy due to Brownian rotation. Multiphoton excitation is shown to give a higher dynamic range of measurement than one-photon excitation. We illustrate the sub-nanometre resolution and stability of our approach by detecting a 0.8-1.1 nm silica particle hydrodynamic mean radius increase in a tetramethylorthosilicate sol at pH 2.3 labelled with rhodamine 6G and observed over ≈4 weeks and also with a stable silica colloid of radius 6 nm, pH 8.9, labelled with a 6-methoxyquinoline-type dye.

  14. Mars climatology from Viking 1 after 20 sols

    NASA Technical Reports Server (NTRS)

    Hess, S. L.; Henry, R. M.; Greene, G. C.; Leovy, C. B.; Tillman, J. E.; Ryan, J. A.; Chamberlain, T. E.; Cole, H. L.; Dutton, R. G.; Simon, W. E.

    1976-01-01

    Results from the meteorology instruments on the Viking 1 lander are presented for the first 20 sols of operation. The daily patterns of temperature, wind, and pressure have been highly consistent during the period. Hence, these have been assembled into 20-sol composistes and analyzed harmonically. Maximum temperature was 241.8 K and minimum was 187.2 K. The composite wind vector has a mean diurnal magnitude of 2.4 meters per second with prevailing wind from the south and counterclockwise diurnal rotation. Pressure exhibits diurnal and semidiurnal oscillations. The diurnal is ascribed to a combination of effects, and the semidiurnal appears to be the solar semidiurnal tide. Similarities to earth are discussed. A major finding is a continual secular decrease in diurnal mean pressure. This is ascribed to carbon dioxide deposition at the south polar cap.

  15. Color Views of Soil Scooped on Sol 9

    NASA Technical Reports Server (NTRS)

    2008-01-01

    These three color views show the Robotic Arm scoop from NASA's Phoenix Mars Lander. The image shows a handful of Martian soil dug from the digging site informally called 'Knave of Hearts,' from the trench informally called 'Dodo,' on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). 'Dodo' is the same site as the earlier test trench dug on the seventh Martian day of the mission, or Sol 7 (June 1, 2008).

    The Robotic Arm Camera took the three color views at different focus positions. Scientists can better study soil structure and estimate how much soil was collected by taking multiple images at different foci.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  16. Tunable Optical Properties of Metal Nanoparticle Sol-Gel Composites

    NASA Technical Reports Server (NTRS)

    Smith, David D.; Snow, Lanee A.; Sibille, Laurent; Ignont, Erica

    2001-01-01

    We demonstrate that the linear and non-linear optical properties of sol-gels containing metal nanoparticles are highly tunable with porosity. Moreover, we extend the technique of immersion spectroscopy to inhomogeneous hosts, such as aerogels, and determine rigorous bounds for the average fractional composition of each component, i.e., the porosity of the aerogel, or equivalently, for these materials, the catalytic dispersion. Sol-gels containing noble metal nanoparticles were fabricated and a significant blue-shift in the surface plasmon resonance (SPR) was observed upon formation of an aerogel, as a result of the decrease in the dielectric constant of the matrix upon supercritical extraction of the solvent. However, as a result of chemical interface damping and aggregation this blue-shift does not strictly obey standard effective medium theories. Mitigation of these complications is achieved by avoiding the use of alcohol and by annealing the samples in a reducing atmosphere.

  17. Sol-gel synthesis of monolithic materials with hierarchical porosity.

    PubMed

    Feinle, A; Elsaesser, M S; Hüsing, N

    2016-06-13

    The development of synthetic routes to hierarchically organized porous materials containing multiple, discrete sets of pores having disparate length scales is of high interest for a wide range of applications. One possible route towards the formation of multilevel porous architectures relies on the processing of condensable, network forming precursors (sol-gel processes) in the presence of molecular porogens, lyotropic mesophases, supramolecular architectures, emulsions, organic polymers, or ice. In this review the focus is on sol-gel processing of inorganic and organic precursors with concurrently occurring microscopic and/or macroscopic phase separation for the formation of self-supporting monoliths. The potential and the limitations of the solution-based approaches is presented with special emphasis to recent examples of hierarchically organized silica, metal oxides and phosphates as well as carbon monoliths. PMID:26563577

  18. Spirit 360-Degree View, Sol 388 (3D)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1

    [figure removed for brevity, see original site] Figure 2

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 388th martian day, or sol (Feb. 4, 2005). Spirit had driven about 13 meters (43 feet) uphill toward 'Cumberland Ridge' on this sol. This location is catalogued as Spirit's Site 102, Position 513. The view is presented in a cylindrical-perspective projection with geometric and brightness seam correction.

    Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  19. Spirit 360-Degree View on Sol 409 (3D)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1

    [figure removed for brevity, see original site] Figure 2

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on Spirit's 409th martian day, or sol (Feb. 26, 2005). Spirit had driven 2 meters (7 feet) on this sol to get in position on 'Cumberland Ridge' for looking into 'Tennessee Valley' to the east. This location is catalogued as Spirit's Site 108. Rover-wheel tracks from climbing the ridge are visible on the right. The summit of 'Husband Hill' is at the center, to the south. This view is presented in a cylindrical-perspective projection with geometric and brightness seam correction.

    Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  20. AOTF-based remote sensor with sol-gel probe

    SciTech Connect

    Volkan, M.; Lee, Y.; Vo-Dinh, T.

    1999-11-01

    The authors report the development and application of a sensor using acousto-optic tunable filter (AOTF) and sol-gel probe technology. A pH-sensitive probe is used as a model sensing system with dextran derivatives of pH sensitive dyes doped into sol-gel thin films. They used a unique combination of pH-sensitive and pH-insensitive dual-label dye system. For optimization studies, the performance of these films as a pH sensing probe was evaluated using synchronous fluorescence detection. The performance of the prototype AOTF-based monitor using a low-power argon laser as an ion excitation source was evaluated.

  1. Opportunity's View on Sols 1803 and 1804 (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,803rd and 1,804th Martian days, or sols, of Opportunity's surface mission (Feb. 18 and 19, 2009). South is at the center; north at both ends.

    The rover had driven 55 meters on Sol 1803 before beginning to take the frames in this view. Tracks from that drive recede northward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a vertical projection with geometric seam correction.

  2. Opportunity's View on Sols 1803 and 1804 (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,803rd and 1,804th Martian days, or sols, of Opportunity's surface mission (Feb. 18 and 19, 2009). South is at the center; north at both ends.

    The rover had driven 55 meters on Sol 1803 before beginning to take the frames in this view. Tracks from that drive recede northward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a polar projection with geometric seam correction.

  3. Dust Devil in Spirit's View Ahead on Sol 1854

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,854th Martian day, or sol, of Spirit's surface mission (March 21, 2009).

    The rover had driven 13.79 meters (45 feet) westward earlier on Sol 1854.

    West is at the center, where a dust devil is visible in the distance. North on the right, where Husband Hill dominates the horizon; Spirit was on top of Husband Hill in September and October 2005. South is on the left, where lighter-toned rock lines the edge of the low plateau called 'Home Plate.'

    This view is presented as a cylindrical projection with geometric seam correction.

  4. Nanostructured energetic materials using sol-gel methodologies

    SciTech Connect

    Tillotson, T M; Simpson, R L; Hrubesh, L W; Gash, A E; Thomas, I M; Poco, J F

    2000-09-27

    The fundamental differences between energetic composites and energetic materials made from a monomolecular approach are the energy density attainable and the energy release rates. For the past 4 years, we have been exploiting sol-gel chemistry as a route to process energetic materials on a microstructural scale. At the last ISA conference, we described four specific sol-gel approaches to fabricating energetic materials and presented our early work and results on two methods - solution crystallization and powder addition. Here, we detail our work on a third approach, energetic nanocomposites. Synthesis of thermitic types of energetic nanocomposites are presented using transition and main group metal-oxide skeletons. Results on characterization of structure and performance will also be given.

  5. Nanostructured Energetci Matreials with sol-gel Chemistry

    SciTech Connect

    Gash, A; Satcher, J; Simpson, R; Clapsaddle, B

    2003-11-18

    The utilization of nanomaterials in the synthesis and processing of energetic materials (i.e., pyrotechnics, explosives, and propellants) is a relatively new area of science and technology. Previous energetic nanomaterials have displayed new and potentially beneficial properties, relative to their conventional analogs. Unfortunately some of the energetic nanomaterials are difficult and or expensive to produce. At LLNL we are studying the application of sol-gel chemical methodology to the synthesis of energetic nanomaterials components and their formulation into energetic nanocomposites. Here sol-gel synthesis and formulation techniques are used to prepare Fe{sub 2}O{sub 3}/Al pyrotechnic nanocomposites. The preliminary characterization of their thermal properties and the degree of mixing between fuel and oxidizer phases is contrasted with that of a conventional pyrotechnic mixture.

  6. Los1p, Involved in Yeast Pre-Trna Splicing, Positively Regulates Members of the Sol Gene Family

    PubMed Central

    Shen, W. C.; Stanford, D. R.; Hopper, A. K.

    1996-01-01

    To understand the role of Los1p in pre-tRNA splicing, we sought los1 multicopy suppressors. We found SOL1 that suppresses both point and null LOS1 mutations. Since, when fused to the Gal4p DNA-binding domain, Los1p activates transcription, we tested whether Los1p regulates SOL1. We found that los1 mutants have depleted levels of SOL1 mRNA and Sollp. Thus, LOS1 appears to positively regulate SOL1. SOL1 belongs to a multigene family with at least two additional members, SOL2 and SOL3. Sol proteins have extensive similarity to an unusual group of glucose-6-phosphate dehydrogenases. As the similarities are restricted to areas separate from the catalytic domain, these G6PDs may have more than one function. The SOL family appears to be unessential since cells with a triple disruption of all three SOL genes are viable. SOL gene disruptions negatively affect tRNA-mediated nonsense suppression and the severity increases with the number of mutant SOL genes. However, tRNA levels do not vary with either multicopy SOL genes or with SOL disruptions. Therefore, the Sol proteins affect tRNA expression/function at steps other than transcription or splicing. We propose that LOS1 regulates gene products involved in tRNA expression/function as well as pre-tRNA splicing. PMID:8725220

  7. Opportunity Self-Portrait, Sols 322-323

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Opportunity used its panoramic camera to take the images combined into this mosaic view of the rover. The downward-looking view omits the mast on which the camera is mounted. It shows Opportunity's solar panels to be relatively dust-free. The images were taken through the camera's 600-, 530- and 480-nanometer filters during Opportunity's 322nd and 323rd martian days, or sols (Dec. 19 and 20, 2004).

  8. Spirit Self-Portrait, Sols 329-330

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit used its panoramic camera to take the images combined into this mosaic view of the rover. The downward-looking view omits the mast on which the camera is mounted. It shows dust accumulation on Spirit's solar panels. The images were taken through the camera's 600-, 530- and 480-nanometer filters during Spirit's 329th and 330th martian days, or sols (Dec. 7 and 8, 2004).

  9. View of Phoenix's Surroundings as of Sol 2

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is a cylindrical mosaic of all data, as of the end of sol 2, from the right eye of the Surface Stereo Imager (SSI) instrument on board the Phoenix lander.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  10. Sol-Gel Thin Films for Plasmonic Gas Sensors

    PubMed Central

    Della Gaspera, Enrico; Martucci, Alessandro

    2015-01-01

    Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors. PMID:26184216

  11. Recent Nuclear Astrophysics Measurements using the TwinSol Separator

    NASA Astrophysics Data System (ADS)

    Bardayan, D. W.; Ahn, T.; Allen, J.; Becchetti, F. D.; Blackmon, J. C.; Brodeur, M.; Frentz, B.; Gupta, Y. K.; Hall, M. R.; Hall, O.; Henderson, S.; Hu, J.; Kelly, J. M.; Kolata, J. J.; Long, A.; Long, J.; Macon, K.; Nicoloff, C.; O'Malley, P. D.; Ostdiek, K.; Pain, S. D.; Riggins, J.; Schultz, B. E.; Smith, M.; Strauss, S.; Torres-Isea, R. O.

    2016-07-01

    Many astrophysical events, such as novae and X-ray bursts, are powered by reactions with radioactive nuclei. Studying the properties of these nuclei in the laboratory can therefore further our understanding of these astrophysical explosions. The TwinSol separator at the University of Notre Dame has recently been used to produce intense (∼106 pps) beams of 17F. In this article, some of the first measurements with these beams are discussed.

  12. Inhomogeneous distribution of organic molecules adsorbed in sol gel glasses

    NASA Astrophysics Data System (ADS)

    Meneses-Nava, M. A.; Chávez-Cerda, S.; Sánchez-Villicaña, V.; Sánchez-Mondragón, J. J.; King, T. A.

    1999-09-01

    The effects of the porous matrix upon the radiative characteristics of quinine sulphate doped sol-gel glasses are investigated. The broadenings of the absorption and fluorescence spectra are explained by the attachment of the molecules on distorted sites or in a non-planar fashion, creating an inhomogeneous distribution of adsorbed molecules. For this reason, each emitting center relaxes with its own characteristics. This inhomogeneous distribution is also supported by the non-exponential and the wavelength dependence of the fluorescence decay.

  13. Opportunity's View After Drive on Sol 1806 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11816 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11816

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction.

    The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  14. Synthesis of zirconium oxide nanoparticle by sol-gel technique

    SciTech Connect

    Lim, H. S.; Ahmad, A.; Hamzah, H.

    2013-11-27

    Zirconium oxide nanoparticle is synthesized using sol-gel technique. Various mole ratio of ammonia solution and nitric acid relative to zirconium propoxide is added in the reaction to study the effect on the crystallinity and particle size on zirconium oxide particle. Zirconium oxide synthesized with nitric acid have the smallest particle size under FESEM image and show the increasing formation of crystalline tetragonal phase under XRD diffractogram.

  15. Piezoelectric Sol-Gel Composite Film Fabrication by Stencil Printing.

    PubMed

    Kaneko, Tsukasa; Iwata, Kazuki; Kobayashi, Makiko

    2015-09-01

    Piezoelectric films using sol-gel composites could be useful as ultrasonic transducers in various industrial fields. For sol-gel composite film fabrication, the spray coating technique has been used often because of its adaptability for various substrates. However, the spray technique requires multiple spray coating processes and heating processes and this is an issue of concern, especially for on-site fabrication in controlled areas. Stencil printing has been developed to solve this issue because this method can be used to fabricate thick sol-gel composite films with one coating process. In this study, PbTiO3 (PT)/Pb(Zr,Ti)O3 (PZT) films, PZT/PZT films, and Bi4Ti3O12 (BiT)/PZT films were fabricated by stencil printing, and PT/ PZT films were also fabricated using the spray technique. After fabrication, a thermal cycle test was performed for the samples to compare their ultrasonic performance. The sensitivity and signal-to-noise-ratio (SNR) of the ultrasonic response of PT/PZT fabricated by stencil printing were equivalent to those of PT/PZT fabricated by the spray technique, and better than those of other samples between room temperature and 300°C. Therefore, PT/PZT films fabricated by stencil printing could be a good candidate for nondestructive testing (NDT) ultrasonic transducers from room temperature to 300°C. PMID:26688872

  16. Sol-gel Technology and Advanced Electrochemical Energy Storage Materials

    NASA Technical Reports Server (NTRS)

    Chu, Chung-tse; Zheng, Haixing

    1996-01-01

    Advanced materials play an important role in the development of electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. The sol-gel process is a versatile solution for use in the fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. This processing technique is particularly useful in producing porous materials with high surface area and low density, two of the most desirable characteristics for electrode materials. In addition,the porous surface of gels can be modified chemically to create tailored surface properties, and inorganic/organic micro-composites can be prepared for improved material performance device fabrication. Applications of several sol-gel derived electrode materials in different energy storage devices are illustrated in this paper. V2O5 gels are shown to be a promising cathode material for solid state lithium batteries. Carbon aerogels, amorphous RuO2 gels and sol-gel derived hafnium compounds have been studied as electrode materials for high energy density and high power density electrochemical capacitors.

  17. Bright Soil Churned by Spirit's Sol 1861 Drive

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit drove 22.7 meters (74 feet) toward the southwest on the 1,861st Martian day, or sol, of Spirit's mission on Mars (March 28, 2009). After the drive, the rover took this image with its front hazard-avoidance camera, looking back at the tracks from the drive.

    As usual since losing the use of its right-front wheel in 2006, Spirit drove backwards. The immobile right-front wheel churned up a long stripe of bright soil during this drive. Where Spirit has found such bright soil in the past, subsequent analysis of the composition found concentrations of sulfur or silica that testified to past action of water at the site. When members of the rover team saw the large quantity of bright soil exposed by the Sol 1861 drive, they quickly laid plans to investigate the composition with Spirit's alpha particle X-ray spectrometer.

    The Sol 1861 drive took the rover past the northwest corner of the low plateau called 'Home Plate,' making progress on a route around the western side of Home Plate. The edge of Home Plate forms the horizon on the right side of this image. Husband Hill is on the horizon on the left side. For scale, the parallel rover wheel tracks are about 1 meter (40 inches) apart. The rover's hazard-avoidance cameras take 'fisheye' wide-angle images.

  18. Sol-gel-derived thick-film amperometric immunosensors.

    PubMed

    Wang, J; Pamidi, P V; Rogers, K R

    1998-03-15

    Sol-gel processing is used for the first time for the preparation of electrochemical immunosensors. One-step sensor fabrication, based on the coupling of sol-gel and screen-printing technologies, is employed. A low-temperature cured ink is prepared by dispersion of rabbit immunoglobulin G (RIgG), graphite powder, and a binder in the sol-gel solution. The enzyme-labeled antibody can readily diffuse toward the encapsulated antigen, which retains its binding properties, and the association reaction is easily detected at the dispersed graphite surface. Use of anti-RIgG labeled with alkaline phosphatase, naphthyl phosphate as the substrate, and amperometric detection at +400 mV (vs Ag/AgCl) results in a low detection limit of 5 ng/mL (32 pM) for the solution antigen. Tailoring the porosity of the ceramic-carbon matrix can be used for tuning the assay performance. The high sensitivity, low cost, durability, and simplicity of the new single-use immunosensors make them well suited for various on-site applications. PMID:9530007

  19. Sol-gel thin films for photonic application

    NASA Astrophysics Data System (ADS)

    Jasieniak, Jacek J.; Martucci, Alessandro

    2012-06-01

    For the fabrication of photonic devices the sol-gel technique is a potentially lucrative alternative to methods such as physical vapor or chemical vapor deposition because of its solution-processability, low cost and relative ease of production. In this work we harness this potential by developing based photonic devices which incorporate highly luminescent CdSe@ZnS core-shell semiconductor quantum dots (QDs) doped within inorganic (TiO2, ZrO2) or hybrid organic-inorganic sol-gel films. As a pre-requisite to the formation of such devices, luminescent waveguides emitting between green and red have been obtained and their optical properties have been characterized. The photochemical stability of these waveguides was found to highly dependent on the exact sol-gel material used. QDs:Titania based composites were found to be inherently photo-unstable due to photoelectron injection into the bulk matrix and subsequent nanocrystal oxidation. In comparison, zirconia composites were significantly more robust with high photoluminescence retained up to annealing temperatures of 300 °C. Despite this difference in photo-chemical stability, both titania and zirconia composite waveguides exhibited amplified stimulated emission (ASE) with one-photon and two-photon optical pumping, however only zirconia based waveguides exhibited long term photostability. This Zirconia based films have been used for the realization of distributed feedback lasers and Bragg micro-cavities.

  20. Granulation of sol-gel-derived nanostructured alumina

    SciTech Connect

    Deng, S.G.; Lin, Y.S.

    1997-02-01

    A sol-gel granulation process was developed to prepare porous nanostructured {gamma}-alumina granules as supports for catalysts and adsorbents. The process, which starts with an aqueous sol of gelatinous boehmite, involves droplet formation, gelation in paraffin oil, conditioning in ammonia solution, and drying and calcination in air under controlled conditions. The {gamma}-Al{sub 2}O{sub 3} granules prepared are 1--3 mm-dia. spherical particles with large surface area (380 m{sup 2}/g) and pore volume (0.5 cm{sup 3}/g), uniform pore-size distribution (20--60 {angstrom}), and controllable average pore size (35 {angstrom}). These sol-gel-derived granules have excellent mechanical properties with crush strength (>100 N per granule) and attrition resistance (<0.01 wt.%/h), much better than the commercial alumina and zeolite granules. Supported CuO sorbents were prepared on these granules for SO{sub 2} removal applications. The alumina-supported CuO sorbents contain higher loading of well-dispersed CuO and better sulfation properties than similar sorbents reported in the literature.

  1. The Influence of Microgravity on Silica Sol-Gel Formation

    NASA Technical Reports Server (NTRS)

    Sibille, L.; Smith, D. D.; Cronise, R.; Hunt, A. J.; Wolfe, D. B.; Snow, L. A.; Oldenberg, S.; Halas, N.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    We discuss space-flight experiments involving the growth of silica particles and gels. The effect of microgravity on the growth of silica particles via the sol-gel route is profound. In four different recipes spanning a large range of the parameter space that typically produces silica nanoparticles in unit-gravity, low-density gel structures were instead formed in microgravity. The particles that did form were generally smaller and more polydisperse than those grown on the ground. These observations suggest that microgravity reduces the particle growth rate, allowing unincorporated species to form aggregates and ultimately gel. Hence microgravity favors the formation of more rarefied structures, providing a bias towards diffusion-limited cluster-cluster aggregation. These results further suggest that in unit gravity, fluid flows and sedimentation can significantly perturb sol-gel substructures prior to gelation and these deleterious perturbations may be "frozen" into the resulting microstructure. Hence, sol-gel pores may be expected to be smaller, more uniform, and less rough when formed in microgravity.

  2. Spirit's View Beside 'Home Plate' on Sol 1823

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009).

    The center of the view is toward the south-southwest.

    The rover had driven 7 meters (23 feet) eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau.

    Layered rocks forming part of the northern edge of Home Plate can be seen near the center of the image. Rover wheel tracks are visible at the lower edge.

    This view is presented as a cylindrical projection with geometric seam correction.

  3. Los1p, involved in yeast pre-tRNA splicing, positively regulates members of the SOL gene family

    SciTech Connect

    Shen, W.C.; Stanford, D.R.; Hopper, A.K.

    1996-06-01

    To understand the role of Los1p in pre-tRNA splicing, we sought los1 multicopy suppressors. We found SOL1 that suppresses both point and null LOS1 mutations. Since, when fused to the Gal4p DNA-binding domain, Los1p activates transcription, we tested whether Los1p regulates SOL1. We found that los1 mutants have depleted levels of SOL1 mRNA and Sol1p. Thus, LOS1 appears to positively regulate SOL1. SOL1 belongs to a multigene family with at least two additional members, SOL2 and SOL3. Sol proteins have extensive similarity to an unusual group of glucose-6-phosphate dehydrogenases (G6PDs). As the similarities are restricted to areas separate from the catalytic domain, these G6PDs may have more than one function. The SOL gene disruptions negatively affect tRNA-mediated nonsense suppression and the severity increases with the number of mutant SOL genes. However, tRNA levels do not vary with either multicopy SOL genes or with SOL disruptions. Therefore, the Sol proteins affect tRNA expression/function at steps other than transcription or splicing. We propose that LOS1 regulates gene products involved in tRNA expression/function as well as pre-tRNA splicing. 64 refs., 6 figs., 6 tabs.

  4. Sol-gel kinetics: /sup 29/SI NMR and a statistical reaction model

    SciTech Connect

    Assink, R.A.; Kay, B.D.

    1988-01-01

    Sol-gel processes allow one to prepare novel materials at low processing temperatures. A detailed understanding of the chemical kinetics of such systems is important to fully exploit the unique features of sol-gel processing. This paper describes a systematic approach to the study of sol-gel kinetics which employs /sup 29/Si NMR spectroscopy and kinetic modelling techniques. 2 figs., 1 tab.

  5. A New Formulation for Hybrid LES-RANS Computations

    NASA Technical Reports Server (NTRS)

    Woodruff, Stephen L.

    2013-01-01

    Ideally, a hybrid LES-RANS computation would employ LES only where necessary to make up for the failure of the RANS model to provide sufficient accuracy or to provide time-dependent information. Current approaches are fairly restrictive in the placement of LES and RANS regions; an LES-RANS transition in a boundary layer, for example, yields an unphysical log-layer shift. A hybrid computation is formulated here to allow greater control over the placement of LES and RANS regions and the transitions between them. The concept of model invariance is introduced, which provides a basis for interpreting hybrid results within an LES-RANS transition zone. Consequences of imposing model invariance include the addition of terms to the governing equations that compensate for unphysical gradients created as the model changes between RANS and LES. Computational results illustrate the increased accuracy of the approach and its insensitivity to the location of the transition and to the blending function employed.

  6. Spirit's View Beside 'Home Plate' on Sol 1823 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11971 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11971

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009).

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The center of the view is toward the south-southwest.

    The rover had driven 7 meters (23 feet) eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau.

    Layered rocks forming part of the northern edge of Home Plate can be seen near the center of the image. Rover wheel tracks are visible at the lower edge.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  7. Modified sol-gel coatings for biotechnological applications

    NASA Astrophysics Data System (ADS)

    Beganskiene, A.; Raudonis, R.; Zemljic Jokhadar, S.; Batista, U.; Kareiva, A.

    2007-12-01

    The modified sol-gel derived silica coatings were prepared and characterized. The amino and methyl groups were introduced onto the colloidal silica. The silica coatings with different wettability properties: coloidal silica (water contact angle 17°), polysiloxane (61°), methyl-modified (158° and 46°) coatings samples were tested for CaCo-2 cells proliferation. Methyl-modified coating (46°) proved to be the best substrate for cell proliferation. CaCo-2 cell proliferation two days post seeding was significantly faster on almost laminine, fibronectin and collagen-1 coated samples compared to corresponding controls.

  8. Spirit's Surroundings on 'West Spur,' Sol 305 (Polar)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a polar projection with geometric seam correction.

  9. Spirit's Surroundings on 'West Spur,' Sol 305 (Vertical)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This 360-degree panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The view is presented here as a vetical projection with geometric seam correction.

  10. Study of silica sol-gel materials for sensor development

    NASA Astrophysics Data System (ADS)

    Lei, Qiong

    Silica sol-gel is a transparent, highly porous silicon oxide glass made at room temperature by sol-gel process. The name of silica sol-gel comes from the observable physical phase transition from liquid sol to solid gel during its preparation. Silica sol-gel is chemically inert, thermally stable, and photostable, it can be fabricated into different desired shapes during or after gelation, and its porous structure allows encapsulation of guest molecules either before or after gelation while still retaining their functions and sensitivities to surrounding environments. All those distinctive features make silica sol-gel ideal for sensor development. Study of guest-host interactions in silica sol-gel is important for silica-based sensor development, because it helps to tailor local environments inside sol-gel matrix so that higher guest loading, longer shelf-life, higher sensitivity and faster response of silica gel based sensors could be achieved. We focused on pore surface modification of two different types of silica sol-gel by post-grafting method, and construction of stable silica hydrogel-like thin films for sensor development. By monitoring the mobility and photostability of rhodamine 6G (R6G) molecules in silica alcogel thin films through single molecule spectroscopy (SMS), the guest-host interactions altered by post-synthesis grafting were examined. While physical confinement remains the major factor that controls mobility in modified alcogels, both R6G mobility and photostability register discernable changes after surface charges are respectively reversed and neutralized by aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTES) grafting. The change in R6G photostability was found to be more sensitive to surface grafting than that of mobility. In addition, silica film modification by 0.4% APTS is as efficient as that by pure MTES in lowering R6G photostability, which suggests that surface charge reversal is more effective than charge neutralization

  11. Titanium (IV) sol-gel chemistry in varied gravity environments

    NASA Astrophysics Data System (ADS)

    Hales, Matthew; Martens, Wayde; Steinberg, Theodore

    Sol-gel synthesis in reduced gravity is a relatively new topic in the literature and further inves-tigation is essential to realise its potential and application to other sol-gel systems. The sol-gel technique has been successfully applied to the synthesis of silica systems of varying porosity for many diverse applications [1-5]. It is proposed that current methods for the synthesis of silica sol-gels in reduced gravity may be applied to titanium sol-gel processing in order to enhance desirable physical and chemical characteristics of the final materials. The physical and chemical formation mechanisms for titanium alkoxide based sol-gels, to date, is not fully understood. However, various authors [6-9] have described potential methods to control the hydrolysis and condensation reactions of titanium alkoxides through the use of chemical inhibitors. A preliminary study of the reaction kinetics of titanium alkoxide sol-gel reaction in normal gravity was undertaken in order to determine reactant mixtures suitable for further testing under varied gravity conditions of limited duration. Through the use of 1H Nuclear Magnetic Resonance spectroscopy (NMR) for structural analysis of precursor materials, Ultra-Violet-Visible spectroscopy (UV-VIS) and viscosity measurements, it was demonstrated that not only could the rate of the chemical reaction could be controlled, but directed linear chain growth within the resulting gel structure was achievable through the use of increased inhibitor concentrations. Two unique test systems have been fabricated to study the effects of varied gravity (reduced, normal, high) on the formation of titanium sol-gels. Whilst the first system is to be used in conjunction with the recently commissioned drop tower facility at Queensland University of Technology in Brisbane, Australia to produce reduced gravity conditions. The second system is a centrifuge capable of providing high gravity environments of up to 70 G's for extended periods of time

  12. Sol Gel-Derived SBA-16 Mesoporous Material

    PubMed Central

    Rivera-Muñoz, Eric M.; Huirache-Acuña, Rafael

    2010-01-01

    The aim of this article is to review current knowledge related to the synthesis and characterization of sol gel-derived SBA-16 mesoporous silicas, as well as a review of the state of the art in this issue, to take stock of knowledge about current and future applications. The ease of the method of preparation, the orderly structure, size and shape of their pores and control, all these achievable through simple changes in the method of synthesis, makes SBA-16 a very versatile material, potentially applicable in many areas of science and molecular engineering of materials. PMID:20957080

  13. Uncooled microbolometer IR FPA based on sol-gel VOx

    NASA Astrophysics Data System (ADS)

    Ovsyuk, V. N.; Shashkin, V. V.; Dem'yanenko, M. A.; Fomin, B. I.; Vasil'ieva, L. L.; Soloviev, A. P.

    2005-06-01

    The technology of high-quality uncooled focal plane arrays (FPA) fabrication has been developed. Simple and cheap sol-gel technology of thermosensitive vanadium oxide layers preparation is underlain in its basis. Uncooled 160x120 and 320x240 FPA for 8-14 microns spectral range have been fabricated. The noise equivalent temperature difference less than 8OmK has been achieved at frame rate 60 Hz for 160x120 FPA and at use of optics with 1/1 relative aperture.

  14. Irradiation of linear polyethylene - Partitioning between sol and gel.

    NASA Technical Reports Server (NTRS)

    Rijke, A. M.; Mandelkern, L.

    1971-01-01

    Investigation of the importance of chain-scission processes and of the applicability of the general theory of network formation to polyethylene with respect to critical conditions for gelation, using molecular weight fractions of linear polyethylene irradiated at 133 C. The partitioning between sol and gel was found to adhere to the theory just beyond the gel point. Deviations from theory occurred as the irradiation dosage was increased. It was concluded that main-chain scission at the temperatures concerned is not a significant process.

  15. Guided wave measurements for characterization of sol-gel layers

    NASA Astrophysics Data System (ADS)

    Piombini, Hervé; Dieudonne, Xavier; Wood, Thomas; Flory, François

    2013-09-01

    Sol-gel applications require very thick layers with a good understanding of the interfaces. To address this problem, we have installed at CEA Le Ripault a characterization bench using guided waves with assistance from the IM2NP lab in Marseille. This bench allows us to measure the thickness and the refractive index and determine the extinction coefficient of a thin layer. We can distinguish losses at interfaces from those in the bulk according to the chosen propagation mode. This allows us to know if we can stack elementary layers to make thick layers without incurring problems.

  16. Les Troubles Respiratoires Chez Le Brule

    PubMed Central

    Fassi Fihri, J.; Ezzoubi, M.; Boukind, E.H.

    2010-01-01

    Summary A travers une revue de la littérature, cet article se propose d'exposer les particularités des troubles respiratoires chez le brûlé. Ces troubles sont liés à un mécanisme direct, lorsque l'arbre respiratoire est lésé par le transfert d'énergie thermique du à la brûlure et/ou par un mécanisme indirect, lorsque la fonction respiratoire et ventilatoire du poumon est perturbée par les phénomènes loco-régionaux ou généraux du brûlé. Ces troubles respiratoires sont aggravés par l'inhalation des gaz contenus dans la fumée d'incendie. Le diagnostic de ces troubles est clinique et paraclinique. Il doit être précoce et continu. Les patients nécessitent de différents moyens thérapeutiques tels que l'oxygénothérapie, la libération des voies respiratoires, l'amélioration de la mécanique ventilatoire et de la fonction respiratoire, l'antibiothérapie ou la chirurgie des séquelles. Cette prise en charge doit nécessairement être multidisciplinaire. PMID:21991224

  17. Radiation hardening in sol-gel derived Er{sup 3+}-doped silica glasses

    SciTech Connect

    Hari Babu, B. E-mail: matthieu.lancry@u-psud.fr; León Pichel, Mónica; Ollier, Nadège; El Hamzaoui, Hicham; Bigot, Laurent; Savelii, Inna; Bouazaoui, Mohamed; Poumellec, Bertrand; Lancry, Matthieu E-mail: matthieu.lancry@u-psud.fr; Ibarra, Angel

    2015-09-28

    The aim of the present paper is to report the effect of radiation on the Er{sup 3+}-doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er{sup 3+}-doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′{sub δ} point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposure to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er{sup 3+} to Er{sup 2+} ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects.

  18. Development of sol-gel formulations for slow release of phermones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new type of dispenser for slow-release of semiochemicals and sex pheromones was developed based on sol-gel polymers that can be useful in monitoring, mass trapping, and mating disruption in integrated pest management (IPM). Sol-gel matrices exhibit glass characteristics and allow control of the de...

  19. Sol-gel hydroxyapatite coatings on stainless steel substrates.

    PubMed

    Liu, Dean-Mo; Yang, Quanzu; Troczynski, Tom

    2002-02-01

    Thin film hydroxyapatite deposits onto sandblasted 316L stainless steel substrates were prepared using water-based sol-gel technique recently developed in our lab. The coatings were annealed in air at 375 degrees C, 400 degrees C, and 500 degrees C. Phase formation, surface morphology, interfacial microstructure, and interfacial bonding strength of the coatings were investigated. Apatitic structure developed within the coatings while annealing at temperatures > or = 400 degrees C, while those heat-treated at 375 degrees C showed poor crystallinity. The coatings were dense and firmly attached to the underlying substrates, reaching an average bonding strength (as determined through the pull-out test) of 44 MPa. Nano-porous structure was found for the coatings annealed at 500 degrees C, believed to result from grain growth, and causing a slight decrease in the bonding strength. Surface microcracking, although not extensive, occurred after annealing at temperatures > or = 400 degrees C, and was linked to non-uniform thickness of the coating due to roughness of the substrate. A contraction of the coatings as a result of sintering, and phase transition from amorphous (or poor crystalline) to reasonably good crystalline apatite, may be responsible for the loss of structural integrity of the thicker sections of the coatings. It seems quite promising that a dense and adhesive apatite coating can be achieved through water-based sol gel technology after short-term annealing at around 400 degrees C in air. PMID:11771689

  20. Novel thermochromism in silica sol-gel materials

    NASA Astrophysics Data System (ADS)

    Gardener, Martin; Perry, Carole C.

    2000-05-01

    In this contribution we provide evidence for thermochromic color changes unique to silica based materials formed at low temperatures by the sol-gel process. The materials formed have potential application as temperature sensitive light filters, visual temperature indicators, self-diagnostic labels for electronic devices and IR recording media. The dopants, diamine complexes of copper(II)/nickel(II) chloride, change from purple to green following heating to 100 degrees C and revert to purple on cooling in the atmosphere. This color change has been explained by the substitution of water molecules by chloride ions in the first coordination sphere of the metal ions. When the same compounds are incorporated into a silica sol-gel matrix under acidic conditions the gel-glasses may be pale green, dark green, yellow, olive-yellow, blue or brown depending on the metal ion chosen and the extent of thermal treatment. Studies on the complexes themselves and on granular silicas doped with some of the complexes are assisting us in understanding the molecular mechanisms that give rise to these color changes.

  1. Investigation of SOL plasma interaction with graphite PFC

    NASA Astrophysics Data System (ADS)

    Lim, Sun-Taek; Kim, Hyun-Su; Jin, Younggil; Lee, Jin Young; Song, Jae-Min; Kim, Gon-Ho

    2015-08-01

    Morphological changes of graphite plasma facing component (PFC) were investigated with various ion irradiation conditions which may change the sputtering yield and the scrape-off layer (SOL) plasma property. The experiments were carried out by using electron cyclotron resonance deuterium plasma with the conditions of electron density range of 2.5-3.5 × 1011 cm-3, electron temperature range of 3.3-4.1 eV, and ion energy range of 17-100 eV. The graphite morphology was changed from plane to conical tip with increasing ion energy and dose. In addition, morphological changes increase the sputtering yield due to the increase of local angle of ion incidence. The inflow of hydrocarbon causes the increase of electron density and the decrease of electron temperature due to its higher dissociation and ionization rates than those of deuterium. This result suggests that the morphological changes of graphite should be considered in the SOL plasma interaction with graphite PFC.

  2. Opportunity's View on Sols 1803 and 1804 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11812 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11812

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings during the 1,803rd and 1,804th Martian days, or sols, of Opportunity's surface mission (Feb. 18 and 19, 2009). South is at the center; north at both ends.

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 55 meters on Sol 1803 before beginning to take the frames in this view. Tracks from that drive recede northward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  3. Sol - Gel synthesis and characterization of magnesium peroxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Jaison, J.; Ashok raja, C.; Balakumar, S.; Chan, Y. S.

    2015-04-01

    Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO2) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles.

  4. Sol-gel-fluorination synthesis of amorphous magnesium fluoride

    SciTech Connect

    Krishna Murthy, J.; Gross, Udo; Ruediger, Stephan; Kemnitz, Erhard . E-mail: erhard.kemnitz@chemie.hu-berlin.de; Winfield, John M.

    2006-03-15

    The sol-gel fluorination process is discussed for the reaction of magnesium alkoxides with HF in non-aqueous solvents to give X-ray amorphous nano-sized magnesium fluoride with high surface areas in the range of 150-350 m{sup 2}/g (HS-MgF{sub 2}). The H2 type hysteresis of nitrogen adsorption-desorption BET-isotherms is indicative for mesoporous solids. A highly distorted structure causes quite high Lewis acidity, shown by NH{sub 3} temperature-programmed desorption (NH{sub 3}-TPD) and catalytic test reactions. XPS data of amorphous and conventionally crystalline MgF{sub 2} are compared, both show octahedral coordination at the metal site. Thermal analysis, F-MAS NMR- and IR-spectroscopy give information on composition and structure of the precursor intermediate as well as of the final metal fluoride. The preparation of complex fluorides, M{sup +}MgF{sub 3} {sup -}, by the sol-gel route is reported. From the magnesium fluoride gel of the above process thin films for optical application are obtained by, e.g., spin coating.

  5. miSolRNA: A tomato micro RNA relational database

    PubMed Central

    2010-01-01

    Background The economic importance of Solanaceae plant species is well documented and tomato has become a model for functional genomics studies. In plants, important processes are regulated by microRNAs (miRNA). Description We describe here a data base integrating genetic map positions of miRNA-targeted genes, their expression profiles and their relations with quantitative fruit metabolic loci and yield associated traits. miSolRNA provides a metadata source to facilitate the construction of hypothesis aimed at defining physiological modes of action of regulatory process underlying the metabolism of the tomato fruit. Conclusions The MiSolRNA database allows the simple extraction of metadata for the proposal of new hypothesis concerning possible roles of miRNAs in the regulation of tomato fruit metabolism. It permits i) to map miRNAs and their predicted target sites both on expressed (SGN-UNIGENES) and newly annotated sequences (BAC sequences released), ii) to co-locate any predicted miRNA-target interaction with metabolic QTL found in tomato fruits, iii) to retrieve expression data of target genes in tomato fruit along their developmental period and iv) to design further experiments for unresolved questions in complex trait biology based on the use of genetic materials that have been proven to be a useful tools for map-based cloning experiments in Solanaceae plant species. PMID:21059227

  6. After Rasping by Phoenix in 'Snow White' Trench, Sol 60

    NASA Technical Reports Server (NTRS)

    2008-01-01

    NASA's Phoenix Mars Lander used the motorized rasp on the back of its robotic arm scoop during the mission's 60th Martian day, or sol, (July 26, 2008) to penetrate a hard layer at the bottom of a trench informally called 'Snow White.' This view, taken by the lander's Surface Stereo Imager and presented in approximately true color, shows the trench later the same sol.

    Most of the 16 holes left by a four-by-four array of rasp placements are visible in the central area of the image.

    A total 3 cubic centimeters, or about half a teaspoon, of material was collected in the scoop. Material in the scoop was collected both by the turning rasp, which threw material into the scoop through an opening at the back of the scoop, and by the scoop's front blade, which was run over the rasped area to pick up more shavings.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Dust Devil in Spirit's View Ahead on Sol 1854 (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11960 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11960

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,854th Martian day, or sol, of Spirit's surface mission (March 21, 2009).

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The rover had driven 13.79 meters (45 feet) westward earlier on Sol 1854.

    West is at the center, where a dust devil is visible in the distance. North on the right, where Husband Hill dominates the horizon; Spirit was on top of Husband Hill in September and October 2005. South is on the left, where lighter-toned rock lines the edge of the low plateau called 'Home Plate.'

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  8. View Ahead After Spirit's Sol 1861 Drive (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11977 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11977

    NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this stereo, 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009).

    This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

    The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right.

    The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate.

    In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called 'Tsiolkovsky' and is about 40 meters (about 130 feet) from the rover's position.

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  9. Nanostructured energetic materials derived from sol-gel chemistry

    SciTech Connect

    Simpson, R L; Tillotson, T M; Hrubesh, L W; Gash, A E

    2000-03-15

    Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocrystalline ammonium perchlorate, the oxidizer, trapped within its pores. At optimum stoichiometry it has approximately the energy density of HMX. Transmission electron microscopy indicated no ammonium perchlorate crystallites larger than 20 nm while near-edge soft x-ray absorption microscopy showed that nitrogen was uniformly distributed, at least on the scale of less than 80 nm. Small-angle neutron scattering studies were conducted on the material. Those results were consistent with historical ones for this class of nanostructured materials. The average skeletal primary particle size was on the order of 2.7 nm, while the nanocomposite showed the growth of small 1 nm size crystals of ammonium perchlorate with some clustering to form particles greater than 10 nm.

  10. Ultrafast Sol-Gel Synthesis of Graphene Aerogel Materials

    SciTech Connect

    Lim, Mathew; Hu, Matthew; Manandhar, Sandeep; Sakshaug, Avery; Strong, Adam; Riley, Leah; Pauzauskie, Peter J.

    2015-12-01

    Graphene aerogels derived from graphene-oxide (GO) starting materials recently have been shown to exhibit a combination of high electrical conductivity, chemical stability, and low cost that has enabled a range of electrochemical applications. Standard synthesis protocols for manufacturing graphene aerogels require the use of sol-gel chemical reactions that are maintained at high temperatures for long periods of time ranging from 12 hours to several days. Here we report an ultrafast, acid-catalyzed sol-gel formation process in acetonitrile in which wet GO-loaded gels are realized within 2 hours at temperatures below 45°C. Spectroscopic and electrochemical analysis following supercritical drying and pyrolysis confirms the reduction of the GO in the aerogels to sp2 carbon crystallites with no residual carbon–nitrogen bonds from the acetonitrile or its derivatives. This rapid synthesis enhances the prospects for large-scale manufacturing of graphene aerogels for use in numerous applications including sorbents for environmental toxins, support materials for electrocatalysis, and high-performance electrodes for electrochemical capacitors and solar cells.

  11. Nanospherical silica as luminescent markers obtained by sol-gel.

    PubMed

    Azevedo, Caroline B; Batista, TúlioM; de Faria, Emerson H; Rocha, Lucas A; Ciuffi, Katia J; Nassar, Eduardo J

    2015-03-01

    Hybrid nanosilicas constitute a broad study field. They find application as catalysts, pigments, drug delivery systems, and biomaterials, among others, and it is possible to obtain them via the sol-gel methodology. Lanthanide ions present special properties like light emission. Their incorporation into a silica matrix can enhance their luminescent properties, which enables their application as luminescent markers. This work reports on (i) the preparation of luminescent spherical hybrid silica nanoparticles by the hydrolytic sol-gel methodology, (ii) doping of the resulting matrix with the europium(III) ion or its complex with 1,10-phenanthroline, and (iii) characterization of the final powders by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and europium(III) ion photoluminescence. The synthesized materials consisted of hybrid, amorphous, polydispersed nonspherical silicas with average size of 180 nm. Photoluminescence confirmed incorporation of the europium(III) ion and its complex into the silica matrix-the ligand-metal charge transfer band emerged in the excitation spectra. The emission spectra presented the bands corresponding to the transition of the excited state (5)D0 level to (7)FJ (J = 0, 1, 2, 3 and 4). The main emission occurred in the red region; the lifetime was long. These characteristics indicated that the prepared nanospherical hybrid silicas could act as luminescent markers. PMID:25686772

  12. Nanostructured Energetic Materials with Sol-Gel Methods

    SciTech Connect

    Gash, A; Satcher, J; Simpson, R; Clapsaddle, B

    2003-11-25

    The utilization of sol-gel chemical methodology to prepare nanostructured energetic materials as well as the concepts of nanoenergetics is described. The preparation and characterization of two totally different compositions is detailed. In one example, nanostructured aerogel and xerogel composites of sol-gel iron (III) oxide and ultra fine grained aluminum (UFG Al) are prepared, characterized, and compared to a conventional micron-sized Fe{sub 2}O{sub 3}/Al thermite. The exquisite degree of mixing and intimate nanostructuring of this material is illustrated using transmission and scanning electron microscopies (TEM and SEM). The nanocomposite material has markedly different energy release (burn rate) and thermal properties compared to the conventional composite, results of which will be discussed. Small-scale safety characterization was performed aerogels and xerogels of the nanostructured thermite. The second nanostructured energetic material consists of a nanostructured hydrocarbon resin fuel network with fine ammonium perchlorate (NH{sub 4}ClO{sub 4}) oxidizer present.

  13. Sol-gel derived ceramic electrolyte films on porous substrates

    SciTech Connect

    Kueper, T.W.

    1992-05-01

    A process for the deposition of sol-gel derived thin films on porous substrates has been developed; such films should be useful for solid oxide fuel cells and related applications. Yttria-stabilized zirconia films have been formed from metal alkoxide starting solutions. Dense films have been deposited on metal substrates and ceramic substrates, both dense and porous, through dip-coating and spin-coating techniques, followed by a heat treatment in air. X-ray diffraction has been used to determine the crystalline phases formed and the extent of reactions with various substrates which may be encountered in gas/gas devices. Surface coatings have been successfully applied to porous substrates through the control of substrate pore size and deposition parameters. Wetting of the substrate pores by the coating solution is discussed, and conditions are defined for which films can be deposited over the pores without filling the interiors of the pores. Shrinkage cracking was encountered in films thicker than a critical value, which depended on the sol-gel process parameters and on the substrate characteristics. Local discontinuities were also observed in films which were thinner than a critical value which depended on the substrate pore size. A theoretical discussion of cracking mechanisms is presented for both types of cracking, and the conditions necessary for successful thin formation are defined. The applicability of these film gas/gas devices is discussed.

  14. Radial Particle Flux in the SOL of DIII-D During ELMing H-Mode

    SciTech Connect

    Leonard, A W; Boedo, J A; Groth, M; Lipschultz, B L; Porter, G D; Rudakov, D L; Whyte, D G

    2006-06-01

    The radial particle flux in the scrape-off-layer (SOL) during ELMing H-mode is examined in DIII-D as a function of density. The global radial particle flux in the outboard far SOL is determined by a window frame technique. Between ELMs the outboard far SOL particle flux increases strongly with density but remains similar to the particle flux across the separatrix as estimated by the pedestal density and temperature gradients. At low density the steep density gradient of the pedestal extends up to 2 cm outside the separatrix. At high density the density gradient flattens just outside the separatrix making this region critical for assessment of the far SOL particle flux. During ELMs the far SOL particle flux becomes localized to the outboard midplane and the assumptions for the window frame analysis break down. Implications for scaling of main chamber wall particle flux and pedestal fueling are explored.

  15. Fabrication of advanced electrochemical energy materials using sol-gel processing techniques

    NASA Technical Reports Server (NTRS)

    Chu, C. T.; Chu, Jay; Zheng, Haixing

    1995-01-01

    Advanced materials play an important role in electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. They are being used as both electrodes and electrolytes. Sol-gel processing is a versatile solution technique used in fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. The application of sol-gel processing in the fabrication of advanced electrochemical energy materials will be presented. The potentials of sol-gel derived materials for electrochemical energy applications will be discussed along with some examples of successful applications. Sol-gel derived metal oxide electrode materials such as V2O5 cathodes have been demonstrated in solid-slate thin film batteries; solid electrolytes materials such as beta-alumina for advanced secondary batteries had been prepared by the sol-gel technique long time ago; and high surface area transition metal compounds for capacitive energy storage applications can also be synthesized with this method.

  16. Aluminum speciation and thermal evolution of aluminas resulting from modified Yoldas sols

    NASA Astrophysics Data System (ADS)

    Dressler, M.; Nofz, M.; Malz, F.; Pauli, J.; Jäger, C.; Reinsch, S.; Scholz, G.

    2007-09-01

    Aluminas resulting from sols prepared via a modified Yoldas procedure were studied with differential thermal analysis (DTA), differential thermal gravimetrie (DTG), 27Al nuclear magnetic resonance ( 27Al MAS NMR) and X-ray diffraction (XRD) concerning their thermal properties, aluminum speciation and phase content. Hydrolysis of aluminum- sec-butoxide in aluminum nitrate solutions allowed to prepare stable sols with varying NO3-/Al molar ratios, solids contents and pH values. Resulting sols contained different aluminum species including also Al 13 polycations. Sol preparation conditions also determined aluminum speciation in solid products obtained after thermal treatments of gels obtained from these sols. Al 13 polycations and AlO 5 species were found to play an important role for thermally induced transformation from amorphous products via eta-Al 2O 3 to alpha-Al 2O 3. Intermediately formed eta-Al 2O 3 promotes the phase transformation to alpha-Al 2O 3.

  17. Optical fiber sensor having a sol-gel fiber core and a method of making

    DOEpatents

    Tao, Shiquan; Jindal, Rajeev; Winstead, Christopher; Singh, Jagdish P.

    2006-06-06

    A simple, economic wet chemical procedure is described for making sol-gel fibers. The sol-gel fibers made from this process are transparent to ultraviolet, visible and near infrared light. Light can be guided in these fibers by using an organic polymer as a fiber cladding. Alternatively, air can be used as a low refractive index medium. The sol-gel fibers have a micro pore structure which allows molecules to diffuse into the fiber core from the surrounding environment. Chemical and biochemical reagents can be doped into the fiber core. The sol-gel fiber can be used as a transducer for constructing an optical fiber sensor. The optical fiber sensor having an active sol-gel fiber core is more sensitive than conventional evanescent wave absorption based optical fiber sensors.

  18. Criteria for Modeling in LES of Multicomponent Fuel Flow

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Selle, Laurent

    2009-01-01

    A report presents a study addressing the question of which large-eddy simulation (LES) equations are appropriate for modeling the flow of evaporating drops of a multicomponent liquid in a gas (e.g., a spray of kerosene or diesel fuel in air). The LES equations are obtained from the direct numerical simulation (DNS) equations in which the solution is computed at all flow length scales, by applying a spatial low-pass filter. Thus, in LES the small scales are removed and replaced by terms that cannot be computed from the LES solution and instead must be modeled to retain the effect of the small scales into the equations. The mathematical form of these models is a subject of contemporary research. For a single-component liquid, there is only one LES formulation, but this study revealed that for a multicomponent liquid, there are two non-equivalent LES formulations for the conservation equations describing the composition of the vapor. Criteria were proposed for selecting the multicomponent LES formulation that gives the best accuracy and increased computational efficiency. These criteria were applied in examination of filtered DNS databases to compute the terms in the LES equations. The DNS databases are from mixing layers of diesel and kerosene fuels. The comparisons resulted in the selection of one of the multicomponent LES formulations as the most promising with respect to all criteria.

  19. Towards LES Models of Jets and Plumes

    NASA Technical Reports Server (NTRS)

    Webb, A. T.; Mansour, N. N.

    2000-01-01

    As pointed out by Rodi standard integral solutions for jets and plumes developed for discharge into infinite, quiescent ambient are difficult to extend to complex situations, particularly in the presence of boundaries such as the sea floor or ocean surface. In such cases the assumption of similarity breaks down and it is impossible to find a suitable entrainment coefficient. The models are also incapable of describing any but the most slowly varying unsteady motions. There is therefore a need for full time-dependent modeling of the flow field for which there are three main approaches: (1) Reynolds averaged numerical simulation (RANS), (2) large eddy simulation (LES), and (3) direct numerical simulation (DNS). Rodi applied RANS modeling to both jets and plumes with considerable success, the test being a match with experimental data for time-averaged velocity and temperature profiles as well as turbulent kinetic energy and rms axial turbulent velocity fluctuations. This model still relies on empirical constants, some eleven in the case of the buoyant jet, and so would not be applicable to a partly laminar plume, may have limited use in the presence of boundaries, and would also be unsuitable if one is after details of the unsteady component of the flow (the turbulent eddies). At the other end of the scale DNS modeling includes all motions down to the viscous scales. Boersma et al. have built such a model for the non-buoyant case which also compares well with measured data for mean and turbulent velocity components. The model demonstrates its versatility by application to a laminar flow case. As its name implies, DNS directly models the Navier-Stokes equations without recourse to subgrid modeling so for flows with a broad spectrum of motions (high Re) the cost can be prohibitive - the number of required grid points scaling with Re(exp 9/4) and the number of time steps with Re(exp 3/4). The middle road is provided by LES whereby the Navier-Stokes equations are formally

  20. Les enjuex éthiques entourant la recherche en santé sur les enfants

    PubMed Central

    2008-01-01

    RÉSUMÉ La recherche en santé est un devoir moral parce qu’elle est la base des soins probants prodigués par tous les dispensateurs de soins. Des politiques et des règlements précis régissent la tenue des recherches sur des humains. Il faut procéder à une évaluation éthique d’un projet de recherche donné avant de pouvoir l’entreprendre. La recherche sur les enfants pose d’énormes défis en matière de consentement éclairé et d’assentiment, de vulnérabilité et de potentiel de conflit d’intérêts (CDI). Les chercheurs en santé pédiatrique devraient prôner la participation des enfants à la recherche, tout en se montrant attentifs à en limiter les risques.

  1. A 'Pot of Gold' Rich with Nuggets (Sol 163)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This close-up image taken by the Mars Exploration Rover Spirit highlights the nodular nuggets that cover the rock dubbed 'Pot of Gold.' These nuggets appear to stand on the end of stalk-like features. The surface of the rock is dotted with fine-scale pits. Data from the rover's scientific instruments have shown that Pot of Gold contains the mineral hematite, which can be formed with or without water.

    Scientists are planning further observations of this rock, which they hope will yield more insight into the hematite's origins as well as how the enigmatic nuggets formed.

    This image was taken by Spirit's microscopic imager on sol 163 (June 18, 2004). The observed area is 3 centimeters by 3 centimeters (1.2 inches by 1.2 inches).

  2. Spirit's Surroundings on 'West Spur,' Sol 305 (3-D)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1

    [figure removed for brevity, see original site] Figure 2

    This 360-degree stereo panorama shows the terrain surrounding NASA's Mars Exploration Rover Spirit as of the rover's 305th martian day, or sol, (Nov. 11, 2004). At that point, Spirit was climbing the 'West Spur' of the 'Columbia Hills.' The rover had just finished inspecting a rock called 'Lutefisk' and was heading uphill toward an area called 'Machu Picchu.' Spirit used its navigational camera to take the images combined into this mosaic. The rover's location when the images were taken is catalogued as the mission's site 89, position 205. The stereo-anaglyph view presented here is a cylindrical projection with geometric seam correction.

    Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  3. Substituent effects on the sol-gel chemistry of organotrialkoxysilanes

    SciTech Connect

    LOY, DOUGLAS A.; BAUGHER, BRIGITTA M.; BAUGHER, COLLEEN R.; SCHNEIDER, DUANE A.; RAHIMIAN, KAMYAR

    2000-05-09

    Silsesquioxanes have been the subject of intensive study in the past and are becoming important again as a vehicle for introducing organic functionalities into hybrid organic-inorganic materials through sol-gel processing. Depending on the application, the target hybrid material may be required to be a highly cross-linked, insoluble gel or a soluble polymer that can be cast as a thin film or coating. The former has applications such as catalyst supports and separations media; the latter is an economically important method for surface modification or compatiblization for applying adhesives or introducing fillers. Polysilsesquioxanes are readily prepared through the hydrolysis and condensation of organotrialkoxysilanes, though organotriaminosilane and organotrihalosilane monomers can also be used. This paper explores the kinetics of the preparation route.

  4. SolOpt: A Novel Approach to Solar Rooftop Optimization

    SciTech Connect

    Lisell, L.; Metzger, I.; Dean, J.

    2011-01-01

    Traditionally Photovoltaic Technology (PV) and Solar Hot Water Technology (SHW) have been designed with separate design tools, making it difficult to determine the appropriate mix of PV and SHW. A new tool developed at the National Renewable Energy Laboratory changes how the analysis is conducted through an integrated approach based on the life cycle cost effectiveness of each system. With 10 inputs someone with only basic knowledge of the building can simulate energy production from PV and SHW, and predict the optimal sizes of the systems. The user can select from four optimization criteria currently available: Greenhouse Gas Reduction, Net-Present Value, Renewable Energy Production, and Discounted Payback Period. SolOpt provides unique analysis capabilities that aren't currently available in any other software programs. Validation results with industry accepted tools for both SHW and PV are presented.

  5. Irradiation of linear polyethylene - Partitioning between sol and gel.

    NASA Technical Reports Server (NTRS)

    Rijke, A. M.; Mandelkern, L.

    1971-01-01

    Molecular weight fractions of linear polyethylene were irradiated at 133 C, in the completely molten and highly crystalline states, for the purpose of assessing the importance of chain-scission processes and establishing the critical conditions for gelation. The partitioning between sol and gel in either state was found to adhere to the theory for the intermolecular cross-linking of monodisperse species for dosages just beyond the gel point. Deviations from theory occurred as the dosage was increased further. It was concluded that main-chain scission, at these temperatures, is not a significant process. High molecular weight samples in the completely molten state obeyed the Flory-Stockmayer condition for critical gelation.

  6. Sol-gel multilayers applied by a meniscus coating process

    SciTech Connect

    Britten, J.A.; Thomas, I.M.

    1992-03-19

    We describe a meniscus coating method to produce high-laser damage threshold, silica/alumina sol-gel multilayer reflectors on 30 {plus} cm substrates for laser-fusion applications. This process involves forcing a small suspension flow through a porous applicator tube, forming a falling film on the tube. A substrate contacts this film to form a meniscus. Motion of the substrate relative to the applicator entrains a thin film on the substrate, which leaves behind a porous, optical quality film upon solvent evaporation. We develop a solution for the entrained film thickness as a function of geometry, flow and fluid properties by an analysis similar to that of the classical dip-coating problem. This solution is compared with experimental measurements. Also, preliminary results of multilayer coating experiments with a prototype coater are presented, which focus on coating uniformity and laser damage threshold (LDT).

  7. Sol-gel synthesis and characterization of mesoporous manganese oxide

    SciTech Connect

    Hong Xinlin; Zhang Gaoyong; Zhu Yinyan; Yang Hengquan

    2003-10-30

    Mesoporous manganese oxide (MPMO) from reduction of KMnO{sub 4} with maleic acid, was obtained and characterized in detail. The characterization of the material was confirmed by high-resolution transmission electron microscopy (HRTEM), X-ray powder diffractometry (XRD) and N{sub 2} sorptometry. The results showed that MPMO is a pseudo-crystalline material with complex network pore structure, of which BET specific surface area is 297 m{sup 2}/g and pore size distribution is approximately in the range of 0.7-6.0 nm. The MPMO material turns to cryptomelane when the calcinating temperature rises to 400 deg. C. The optimum sol-gel reaction conditions are KMnO{sub 4}/C{sub 4}H{sub 4}O{sub 4} molar ratio=3, pH=7 and gelation time>6 h.

  8. True Color of Mars - Pathfinder Sol 39 Sunrise

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sunrise, sol 39. This true color, pre-sunrise image (approximately 0530LST) is composed of six images extending 30 o in azimuth and 45 o in elevation and shows the brownish gray predawn sky. A description of the techniques used to generate this color image from IMP data can be found in Maki et al., 1999. Note: a calibrated output device is required accurately reproduce the correct colors.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal investigator.

  9. Wind-Sculpted Vicinity After Opportunity's Sol 1797 Drive

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 111 meters (364 feet) on the 1,797th Martian day, or sol, of Opportunity's surface mission (Feb. 12, 2009). North is at the center; south at both ends.

    Tracks from the drive recede northward across dark-toned sand ripples in the Meridiani Planum region of Mars. Patches of lighter-toned bedrock are visible on the left and right sides of the image. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    This view is presented as a cylindrical projection with geometric seam correction.

  10. Wind-Sculpted Vicinity After Opportunity's Sol 1797 Drive (Polar)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 111 meters (364 feet) on the 1,797th Martian day, or sol, of Opportunity's surface mission (Feb. 12, 2009). North is at the center; south at both ends.

    Tracks from the drive recede northward across dark-toned sand ripples in the Meridiani Planum region of Mars. Patches of lighter-toned bedrock are visible on the left and right sides of the image. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    This view is presented as a polar projection with geometric seam correction.

  11. Wind-Sculpted Vicinity After Opportunity's Sol 1797 Drive (Vertical)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 111 meters (364 feet) on the 1,797th Martian day, or sol, of Opportunity's surface mission (Feb. 12, 2009). North is at the center; south at both ends.

    Tracks from the drive recede northward across dark-toned sand ripples in the Meridiani Planum region of Mars. Patches of lighter-toned bedrock are visible on the left and right sides of the image. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    This view is presented as a vertical projection with geometric seam correction.

  12. Conductivity Probe Inserted in Martian Soil, Sol 46

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander shows the lander's Thermal and Electrical Conductivity Probe (TECP), at the end of the Robotic Arm, on the 46th Martian day, or sol, of the mission (July 11, 2008).

    The TECP is inserted at a site called Vestri, which was monitored several times over the course of the mission. The probe's measurements at this site yielded evidence that water was exchanged, daily and seasonally, between the soil and atmosphere.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  13. Operation of electrochromic devices prepared by sol-gel methods

    NASA Astrophysics Data System (ADS)

    Tulloch, Gavin; Skryabin, Igor L.; Evans, Graeme; Bell, John M.

    1997-10-01

    The manufacturing and operation of window size (30 cm by 90 cm) electrochromic devices is described. Both the electrochromic electrode (WO3) and the counter electrode (V2O5) were deposited by sol-gel method. Electrochromic measurements were performed on both electrodes and the complete device to correlate device performance to fabrication conditions. The paper describes the affects of temperature on the switching characteristics of electrochromic window. The devices were tested in the temperature range between 10 degrees Celsius and 50 degrees Celsius. The switching algorithm described in this paper ensures identical optical performance of electrochromic device in the wide range of temperatures. The algorithm is based on the charge control and does not require monitoring of device transmittance.

  14. Polymer sol-gel composite inverse opal structures.

    PubMed

    Zhang, Xiaoran; Blanchard, G J

    2015-03-25

    We report on the formation of composite inverse opal structures where the matrix used to form the inverse opal contains both silica, formed using sol-gel chemistry, and poly(ethylene glycol), PEG. We find that the morphology of the inverse opal structure depends on both the amount of PEG incorporated into the matrix and its molecular weight. The extent of organization in the inverse opal structure, which is characterized by scanning electron microscopy and optical reflectance data, is mediated by the chemical bonding interactions between the silica and PEG constituents in the hybrid matrix. Both polymer chain terminus Si-O-C bonding and hydrogen bonding between the polymer backbone oxygens and silanol functionalities can contribute, with the polymer mediating the extent to which Si-O-Si bonds can form within the silica regions of the matrix due to hydrogen-bonding interactions. PMID:25734614

  15. Photosensitivity in a silica-based sol-gel glass

    SciTech Connect

    Korwin, D.M.; Pye, L.D.

    1996-12-31

    Photosensitivity in glasses containing Au and Ce was first reported by Dalton in 1943 and later reaffirmed by Stookey. The photothermal reduction of Au ions to form metallic colloids was determined to be responsible for the {open_quotes}ruby{close_quotes} color produced in these glasses. In this work, the photosensitive effect has been confirmed for the first time in a silica sol-gel glass containing Au and Ce. Two methods of producing Au colloids in this glass were investigated, one involved a short ultraviolet (UV) exposure followed by a thermal treatment, the other a simultaneous UV irradiation and thermal treatment. Colloid formation was studied using optical absorption spectroscopy, whereas the role of Ce in the photosensitive process was elucidated using optical absorption and fluorescence spectroscopic techniques.

  16. Manufacture of Regularly Shaped Sol-Gel Pellets

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Johnston, James C.; Kinder, James D.

    2006-01-01

    An extrusion batch process for manufacturing regularly shaped sol-gel pellets has been devised as an improved alternative to a spray process that yields irregularly shaped pellets. The aspect ratio of regularly shaped pellets can be controlled more easily, while regularly shaped pellets pack more efficiently. In the extrusion process, a wet gel is pushed out of a mold and chopped repetitively into short, cylindrical pieces as it emerges from the mold. The pieces are collected and can be either (1) dried at ambient pressure to xerogel, (2) solvent exchanged and dried under ambient pressure to ambigels, or (3) supercritically dried to aerogel. Advantageously, the extruded pellets can be dropped directly in a cross-linking bath, where they develop a conformal polymer coating around the skeletal framework of the wet gel via reaction with the cross linker. These pellets can be dried to mechanically robust X-Aerogel.

  17. Inhibiteurs de la pompe à protons pour les nourrissons irritables

    PubMed Central

    Smith, Christine H.; Israel, David M.; Schreiber, Richard; Goldman, Ran D.

    2013-01-01

    Résumé Question Les pleurs sont communs chez les nourrissons; par ailleurs, prendre soin d'un nourrisson dont les pleurs sont inconsolables et qu'on surnommait aussi auparavant des coliques ou un reflux, peut souvent causer une détresse extrême aux parents. Le recours à un agent de suppression de l'acide gastrique (p. ex. les inhibiteurs de la pompe à protons [IPP]) est-il bénéfique chez ces nourrissons? Réponse On utilise de plus en plus les IPP chez les nourrissons et les enfants depuis quelques années. L'efficacité des inhibiteurs de la pompe à protons n'a pas été démontrée dans le traitement de l'irritabilité et des pleurs excessifs chez des enfants autrement en santé de moins de 3 mois. D'autre part, si les IPP sont généralement bien tolérés, il existe certaines données probantes reliant l'utilisation des IPP avec une susceptibilité accrue aux gastroentérites aiguës, à la pneumonie acquise dans la communauté et à des troubles de l'utilisation et de l'absorption des nutriments. Indépendamment des traitements, les pleurs et l'irritabilité durant la tendre enfance s'améliorent généralement avec le temps. Entre-temps, les inhibiteurs de la pompe à protons n'améliorent pas les symptômes.

  18. Sol-gel processes and materials. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations of selected patents concerning sol-gel processes and sol-gel derived materials and products. Selected patents include sol-gel compositions, ceramic and refractory materials, fabrication of silica glass, sol-gel thin films and coatings, transparent inorganic oxide glass, luminescent quartz glass, catalysts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, sol-gel production of microspheres, alumina composites, photographic materials, and dental materials. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. Mayenite Synthesized Using the Citrate Sol-Gel Method

    SciTech Connect

    Ude, Sabina N; Rawn, Claudia J; Meisner, Roberta A; Kirkham, Melanie J; Jones, Gregory L.; Payzant, E Andrew

    2014-01-01

    A citrate sol-gel method has been used to synthesize mayenite (Ca12Al14O33). X-ray powder diffraction data show that the samples synthesized using the citrate sol-gel method contained CaAl2O4 and CaCO3 along with mayenite when fired ex-situ in air at 800 C but were single phase when fired at 900 C and above. Using high temperature x-ray diffraction, data collected in-situ in air at temperatures of 600 C and below showed only amorphous content; however, data collected at higher temperatures indicated the first phase to crystallize is CaCO3. High temperature x-ray diffraction data collected in 4% H2/96% N2 does not show the presence of CaCO3, and Ca12Al14O33 starts to form around 850 C. In comparison, x-ray powder diffraction data collected ex-situ on samples synthesized using traditional solid-state synthesis shows that single phase was not reached until samples were fired at 1350 C. DTA/TGA data collected either in a nitrogen environment or air on samples synthesized using the citrate gel method suggest the complete decomposition of metastable phases and the formation of mayenite at 900 C, although the phase evolution is very different depending on the environment. Brunauer-Emmett-Teller (BET) measurements showed a slightly higher surface area of 7.4 0.1 m2/g in the citrate gel synthesized samples compared to solid-state synthesized sample with a surface area of 1.61 0.02 m2/g. SEM images show a larger particle size for samples synthesized using the solid-state method compared to those synthesized using the citrate gel method.

  20. Sol-Gel processing of silica nanoparticles and their applications.

    PubMed

    Singh, Lok P; Bhattacharyya, Sriman K; Kumar, Rahul; Mishra, Geetika; Sharma, Usha; Singh, Garima; Ahalawat, Saurabh

    2014-11-01

    Recently, silica nanoparticles (SNPs) have drawn widespread attention due to their applications in many emerging areas because of their tailorable morphology. During the last decade, remarkable efforts have been made on the investigations for novel processing methodologies to prepare SNPs, resulting in better control of the size, shape, porosity and significant improvements in the physio-chemical properties. A number of techniques available for preparing SNPs namely, flame spray pyrolysis, chemical vapour deposition, micro-emulsion, ball milling, sol-gel etc. have resulted, a number of publications. Among these, preparation by sol-gel has been the focus of research as the synthesis is straightforward, scalable and controllable. Therefore, this review focuses on the recent progress in the field of synthesis of SNPs exhibiting ordered mesoporous structure, their distribution pattern, morphological attributes and applications. The mesoporous silica nanoparticles (MSNPs) with good dispersion, varying morphology, narrow size distribution and homogeneous porous structure have been successfully prepared using organic and inorganic templates. The soft template assisted synthesis using surfactants for obtaining desirable shapes, pores, morphology and mechanisms proposed has been reviewed. Apart from single template, double and mixed surfactants, electrolytes, polymers etc. as templates have also been intensively discussed. The influence of reaction conditions such as temperature, pH, concentration of reagents, drying techniques, solvents, precursor, aging time etc. have also been deliberated. These MSNPs are suitable for a variety of applications viz., in the drug delivery systems, high performance liquid chromatography (HPLC), biosensors, cosmetics as well as construction materials. The applications of these SNPs have also been briefly summarized. PMID:25466691

  1. Erbium-doped sol-gel materials for optical applications

    NASA Astrophysics Data System (ADS)

    Berni, Anette; Mennig, Martin; Schmidt, Helmut K.

    2003-04-01

    A new chemical nanotechnological route for the preparation of fully densified doped SiO2 coatings with thicknesses in the low ´m-range on Si- and SiO2-wafers has been developed. Beside pure SiO2 coatings, that might be useful as a buffer layer on silicon, silicate layers with increased refractive index are needed for planar waveguide application. Therefore, a synthesis for the preparation of nano particulate sols was developed, thus allowing the incorporation of dopands like Al2O3, PbO and Er2O3 for passive and active layers. Alumina was incorporated for the improvement of the Erbium solubility in active components. The coating sols consist of an organic binder, dissolved in a suspension of nanoscaled silica particles (10 nm in diameter) and dopands and were applied on Si- and SiO2-wafers by spin coating. After removal of the binder at 500 °C, investigated by IR-spectroscopy, highly porous (nD = 1.23) but transparent doped silica layers were obtained. The densification of the layers was examined by measuring the refractive index by ellipsometry as a function of the densification temperature. Completely densified layers with thicknesses between 1.7 ´m (doped SiO2) and 6.5 ´m (doped SiO2) were obtained at temperatures between 1000 °C (doped SiO2) and 1100 °C) (pure SiO2). The layer thickness and unevenness was determined by interferometric measurements. The optical loss of Al2O3 and PbO doped layers was measured by prism coupling, the Er2O3 doped layers with Er3+ concentrations of up to 2.5 mole % show fluorescence around 1500 nm with a fluorescence lifetime of about 3.6 ms.

  2. Composite sol-gel process for photocatalytic titanium dioxide

    NASA Astrophysics Data System (ADS)

    Keshmiri, Mehrdad

    Photocatalytic TiO2 decomposes organic and inorganic pollutants upon irradiation with UV light. TiO2 thin films and powder suspensions are used for purification treatments, but small surface area of TiO2 films, and difficult filtration of powders are the two major drawbacks in application of photocatalytic TiO2. The major objective of this work was to develop a novel process to combine the thin film coatings and the fine (sub-micron) powder anatase TiO2 to provide high photocatalytic efficiency thick films and self-supported membranes. The microstructural properties and photocatalytic efficiency of the developed materials were characterized and compared with that of the conventional TiO2 coatings and powders. Photocatalytic activity of CSG TiO 2 was measured through the ability to decompose organic compounds (trichloroethane, dioxane, toluene), as well as to destroy bacteria. The major achievement of this work is the development of a process wherein structurally sound, thick films and membranes of CSG anatase photocatalytic TiO2 can be produced in reproducible way. A novel method for the synthesis of monodispersed anatase TiO2 microspheres through colloidal precipitation has also been established. The microspheres were used as filler TiO2 in the composite microstructure, bonded with sot-gel derived TiO2, to produce the composite sol-gel (CSG) TiO2. A sol-gel-assisted sintering model for the CSG thick films and self-supported membranes was established and validated by experimental data. The model has the ability to predict the sintering behavior of the CSG-TiO2, in terms of the reduction of specific surface area versus the time of heating, particularly at the initial and intermediate stages of the sintering.

  3. Sol-Gel Glass Holographic Light-Shaping Diffusers

    NASA Technical Reports Server (NTRS)

    Yu, Kevin; Lee, Kang; Savant, Gajendra; Yin, Khin Swe (Lillian)

    2005-01-01

    Holographic glass light-shaping diffusers (GLSDs) are optical components for use in special-purpose illumination systems (see figure). When properly positioned with respect to lamps and areas to be illuminated, holographic GLSDs efficiently channel light from the lamps onto specified areas with specified distributions of illumination for example, uniform or nearly uniform irradiance can be concentrated with intensity confined to a peak a few degrees wide about normal incidence, over a circular or elliptical area. Holographic light diffusers were developed during the 1990s. The development of the present holographic GLSDs extends the prior development to incorporate sol-gel optical glass. To fabricate a holographic GLSD, one records a hologram on a sol-gel silica film formulated specially for this purpose. The hologram is a quasi-random, micro-sculpted pattern of smoothly varying changes in the index of refraction of the glass. The structures in this pattern act as an array of numerous miniature lenses that refract light passing through the GLSD, such that the transmitted light beam exhibits a precisely tailored energy distribution. In comparison with other light diffusers, holographic GLSDs function with remarkably high efficiency: they typically transmit 90 percent or more of the incident lamp light onto the designated areas. In addition, they can withstand temperatures in excess of 1,000 C. These characteristics make holographic GLSDs attractive for use in diverse lighting applications that involve high temperatures and/or requirements for high transmission efficiency for ultraviolet, visible, and near-infrared light. Examples include projectors, automobile headlights, aircraft landing lights, high-power laser illuminators, and industrial and scientific illuminators.

  4. Synthesis and characterization of nitric oxide-releasing sol-gel microarrays.

    PubMed

    Robbins, Mary E; Hopper, Erin D; Schoenfisch, Mark H

    2004-11-01

    Diazeniumdiolate-modified sol-gel microarrays capable of releasing low levels of nitric oxide are reported as a viable means for improving the blood compatibility of a surface without fully modifying the underlying substrate. Several parameters are characterized including: (1) NO surface flux as a function of sol-gel composition and microarray geometry; (2) microstructure dimensions and spacing for optimal blood compatibility; and (3) the effect of sol-gel surface modification on analyte accessibility to platinum electrodes. The sol-gel microarrays release biologically relevant levels of NO under physiological conditions for >24 h. In vitro platelet adhesion assays indicate that a NO surface flux of 2.2 pmol cm(-2) s(-1) effectively reduces platelet adhesion to glass substrates modified with sol-gel microstructures separated by 50 microm. The blood compatibility observed for these micropatterned surfaces is comparable to NO-releasing sol-gel films. When the separation between NO-releasing microstructures is reduced to 10 microm, the NO surface flux required to reduce platelet adhesion is lowered to 0.4 pmol cm(-2) s(-1). Finally, the oxygen response of platinum electrodes modified with NO-releasing sol-gel microarrays indicates that selective modification via micropatterning enhances analyte accessibility to the sensor surface. PMID:15518528

  5. A silica sol-gel design strategy for nanostructured metallic materials

    NASA Astrophysics Data System (ADS)

    Warren, Scott C.; Perkins, Matthew R.; Adams, Ashley M.; Kamperman, Marleen; Burns, Andrew A.; Arora, Hitesh; Herz, Erik; Suteewong, Teeraporn; Sai, Hiroaki; Li, Zihui; Werner, Jörg; Song, Juho; Werner-Zwanziger, Ulrike; Zwanziger, Josef W.; Grätzel, Michael; Disalvo, Francis J.; Wiesner, Ulrich

    2012-05-01

    Batteries, fuel cells and solar cells, among many other high-current-density devices, could benefit from the precise meso- to macroscopic structure control afforded by the silica sol-gel process. The porous materials made by silica sol-gel chemistry are typically insulators, however, which has restricted their application. Here we present a simple, yet highly versatile silica sol-gel process built around a multifunctional sol-gel precursor that is derived from the following: amino acids, hydroxy acids or peptides; a silicon alkoxide; and a metal acetate. This approach allows a wide range of biological functionalities and metals—including noble metals—to be combined into a library of sol-gel materials with a high degree of control over composition and structure. We demonstrate that the sol-gel process based on these precursors is compatible with block-copolymer self-assembly, colloidal crystal templating and the Stöber process. As a result of the exceptionally high metal content, these materials can be thermally processed to make porous nanocomposites with metallic percolation networks that have an electrical conductivity of over 1,000 S cm-1. This improves the electrical conductivity of porous silica sol-gel nanocomposites by three orders of magnitude over existing approaches, opening applications to high-current-density devices.

  6. Synthesis of polymeric fluorinated sol-gel precursor for fabrication of superhydrophobic coating

    NASA Astrophysics Data System (ADS)

    Li, Qianqian; Yan, Yuheng; Yu, Miao; Song, Botao; Shi, Suqing; Gong, Yongkuan

    2016-03-01

    A fluorinated polymeric sol-gel precursor (PFT) is synthesized by copolymerization of 2,3,4,5,5,5-hexafluoro-2,4-bis(trifluorinated methyl)pentyl methacrylate (FMA) and 3-methacryloxypropyltrimethoxysilane (TSMA) to replace the expensive long chain fluorinated alkylsilanes. The fluorinated silica sol is prepared by introducing PFT as co-precursor of tetraethyl orthosilicate (TEOS) in the sol-gel process with ammonium hydroxide as catalyst, which is then used to fabricate superhydrophobic coating on glass substrate through a simple dip-coating method. The effects of PFT concentrations on the chemical structure of the formed fluorinated silica, the surface chemical composition, surface morphology, wetting and self-cleaning properties of the resultant fluorinated silica coatings were studied by using X-ray powder diffraction (XRD), Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectrophotometer (XPS), scanning electron microscopy (SEM) and water contact angle measurements (WCA). The results show that the fluorinated silica sols are successfully obtained. The size and size distribution of the fluorinated silica particles are found greatly dependent on the concentration of PFT, which play a crucial role in the surface morphology of the corresponding fluorinated silica coatings. The suitable PFT concentration added in the sol-gel stage, i.e. for F-sol-1 and F-sol-2, is helpful to achieve both the low surface energy and multi-scaled microstructures, leading to the formation of the superhydrophobic coatings with bio-mimicking self-cleaning property similar to lotus leaves.

  7. Crystal structure of Sol I 2: a major allergen from fire ant venom.

    PubMed

    Borer, Aline S; Wassmann, Paul; Schmidt, Margit; Hoffman, Donald R; Zhou, Jing-Jiang; Wright, Christine; Schirmer, Tilman; Marković-Housley, Zora

    2012-01-27

    Sol i 2 is a potent allergen from the venom of red imported fire ant, which contains allergens Sol i 1, Sol i 2, Sol i 3, and Sol i 4 that are known to be powerful triggers of anaphylaxis. Sol i 2 causes IgE antibody production in about one-third of individuals stung by fire ants. Baculovirus recombinant dimeric Sol i 2 was crystallized as a native and selenomethionyl-derivatized protein, and its structure has been determined by single-wavelength anomalous dispersion at 2.6 Å resolution. The overall fold of each subunit consists of five helices that enclose a central hydrophobic cavity. The structure is stabilized by three intramolecular disulfide bridges and one intermolecular disulfide bridge. The nearest structural homologue is the sequence-unrelated odorant binding protein and pheromone binding protein LUSH of the fruit fly Drosophila, which may suggest a similar biological function. To test this hypothesis, we measured the reversible binding of various pheromones, plant odorants, and other ligands to Sol i 2 by the changes in N-phenyl-1-naphthylamine fluorescence emission upon binding of ligands that compete with N-phenyl-1-naphthylamine. The highest binding affinity was observed for hydrophobic ligands such as aphid alarm pheromone (E)-β-farnesene, analogs of ant alarm pheromones, and plant volatiles decane, undecane, and β-caryophyllene. Conceivably, Sol i 2 may play a role in capturing and/or transporting small hydrophobic ligands such as pheromones, odors, fatty acids, or short-living hydrophobic primers. Molecular surface analysis, in combination with sequence alignment, can explain the serological cross-reactivity observed between some ant species. PMID:22100449

  8. Analysis of discretization errors in LES

    NASA Technical Reports Server (NTRS)

    Ghosal, Sandip

    1995-01-01

    All numerical simulations of turbulence (DNS or LES) involve some discretization errors. The integrity of such simulations therefore depend on our ability to quantify and control such errors. In the classical literature on analysis of errors in partial differential equations, one typically studies simple linear equations (such as the wave equation or Laplace's equation). The qualitative insight gained from studying such simple situations is then used to design numerical methods for more complex problems such as the Navier-Stokes equations. Though such an approach may seem reasonable as a first approximation, it should be recognized that strongly nonlinear problems, such as turbulence, have a feature that is absent in linear problems. This feature is the simultaneous presence of a continuum of space and time scales. Thus, in an analysis of errors in the one dimensional wave equation, one may, without loss of generality, rescale the equations so that the dependent variable is always of order unity. This is not possible in the turbulence problem since the amplitudes of the Fourier modes of the velocity field have a continuous distribution. The objective of the present research is to provide some quantitative measures of numerical errors in such situations. Though the focus of this work is LES, the methods introduced here can be just as easily applied to DNS. Errors due to discretization of the time-variable are neglected for the purpose of this analysis.

  9. LES of mixing in coastal areas

    NASA Astrophysics Data System (ADS)

    Armenio, Vincenzo; Roman, Federico

    2008-11-01

    Large eddy simulations of near shore mixing are carried out using a new large-scale model, LES-COAST. The model integrates the Boussinesq form of the NS equations using a curvilinear formulation of the fractional step method. Complex geometry is reproduced with a combination of curvilinear mesh and immersed boundaries. Anisotropy of the problem (δxvert/δxhor˜10-2) has required a two eddy-viscosities model. Specifically we use a mixed model, composed of an anisotropic scale-similar part and an eddy viscosity, Smagorinsky part. Two eddy-viscosities are used, νT,v/h=(Cv/hδv/h)^2 |Sv/h| respectively in the two directions. The quantities δv/h are chosen proportional to the local grid spacings in the two directions. Density stratification is also considered using a very simple SGS model, based on the assumption that PrT= ScT=1. The algorithm is being used for real applications. The following studies will be discussed: the intrusion of fresh water of the Tevere river in the Tirreno sea; mixing in the Muggia Bay (Region of Trieste) under the action of the breeze forcing. Results have clearly shown the reliability of new- generation LES large-scale models for applications in problems with horizontal and vertical scales respectively of the order of 10 km and 50 m.

  10. Mediated patterning of sol-gel thin layers: Shrinkage, decohesion, and lift-off

    NASA Astrophysics Data System (ADS)

    Mikalsen, Erik Arthur

    This thesis explores the unique de-cohesion and lift-off processes that occur during mediated patterning of integrated sol-gel thin films of functional materials. Mediated deposition, an additive patterning approach, was introduced by Jeon et al. (J. Mater. Res., 10[12]: 2996--9 (1995)), where microcontact printing (mu-CP) facilitated the selective transfer of a molecular 'ink' (e.g., octadecyltrichlorosilane, ODTS) to the substrate, and de-cohesion of sol-gel films occurred exclusively above the printed ink regions after heat treatment (<150°C). Patterned sol-gel films of uniform thickness were revealed after facile lift-off of cracked fragments, without the use of etchants. In this thesis, the origin and mechanics of de-cohesion and lift-off were determined through direct observations and measurements. The disparate mechanical behaviors of sol-gel films on functionalized and unmodified surfaces were determined, with emphasis on interfacial strength, in-plane biaxial stress, thin film mechanics, and crack propagation for sol-gel layers on silicon, glass and fused silica substrates. In addition, direct patterning of sol-gel layers was demonstrated for the first time on curved glassy surfaces using mu-CP and mediated patterning methods. The shrinkage and densification of sol-gel layers were determined by in-situ and ex-situ measurements, where a ˜30% decrease in thickness (t) was typical during drying of sol-gel layers (T < 300°C). Constrained shrinkage, resulting from adhesion to the supporting silicon substrate, led to a coherent (crack-free) film with biaxial stresses of ˜200 MPa (t ˜ 50 nm). For ODTS-mediated sol-gel films, however, precise in-situ wafer curvature measurements determined that film stresses never exceeded 75 MPa. Additionally, interfacial adhesive strength between the substrate and the sol-gel film were evaluated for the first time using a unique pulsed-laser stress-wave technique. An adhesive strength threshold of 15 MPa was determined for

  11. Examination of light distribution from sol-gel based applicators for interstitial laser therapy

    NASA Astrophysics Data System (ADS)

    Hołowacz, I.; Ulatowska-Jarża, A.; Podbielska, H.; Garbaczewska, I.

    2006-02-01

    We describe here the construction of sol-gel based applicators for interstitial thermotheraphy. The silica sol-gel coatings were prepared from silicate precursor TEOS (tetraethylorthosilicate) mixed with ethyl alcohol in acid catalyzed hydrolysis. The matrices were produced with various ratios R=5, 10, 20, 32, 50, whereas R denotes the number of solvent molds (here ethanol) to the number of TEOS moles. The spatial light intensity distribution was examined in order to find out the influence of R factor on the light distribution shape. It was shows that the most homogeneous patterns are observed for sol-gel coatings with R factors equal 10 and 20.

  12. Les mémoires de la dynastie Tang

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.

    1996-07-01

    Dans la nuit des temps, les astronomes chinois ont ete d'incomparables observateurs de cometes. Ces savants, dont les notations raffinees ponctuaient l'histoire officielle des empereurs, relevaient chaque passage d'astre errant avec une precision inestimable. Un veritable tresor ou puise encore la science contemporaine.

  13. La Terre - les eaux - l'atmosphère.

    NASA Astrophysics Data System (ADS)

    Bec-Borsenberger, A.; Catoire, M.; Kovalevsky, J.; Guinot, B.; Cazenave, A.; Levallois, J. J.; Lecolazet, R.; Jobert, G.; Francheteau, J.; Le Mouël, J.-L.; Goguel, J.; Serpolay, R.; Berroir, A.; Mégie, G.; Crépon, M.; Saint-Guily, B.; Eyriès, M.-M.; Ramamonjiarisoa, A.; Buat-Menard, P.; Lalou, C.; Serra, L.; Lliboutry, L.; Lorius, C.

    Contents: Repères et forces de gravité (J. Kovalevsky). La rotation de la Terre (B. Guinot). La géodésie (J. Kovalevsky, A. Cazenave, J. J. Levallois). Les marées terrestres (R. Lecolazet). La sismologie (G. Jobert). Lithosphère et tectonique des plaques (J. Francheteau). Le champ magnétique terrestre (J.-L. Le Mouël). Modèles de la constitution physique de la Terre (G. Jobert). La géothermie (J. Goguel). Le rayonnement énergétique (R. Serpolay). Les fluides géophysiques (A. Berroir). L'atmosphère (A. Berroir, R. Serpolay). L'ozonosphère (G. Mégie). Les océans en mouvement (M. Crépon, B. Saint-Guily). La marée océanique (M.-M. Eyriès). La houle et les vagues (A. Ramamonjiarisoa). Les cycles géochimiques dans l'océan (P. Buat-Menard, C. Lalou). La circulation des eaux (L. Serra). Les glaces naturelles et leur dynamique (L. Lliboutry). L'évolution des climats, les données du passé (C. Lorius).

  14. Le sumatriptan intranasal pour la migraine chez les enfants

    PubMed Central

    Goldman, Ran D.; Meckler, Garth D.

    2015-01-01

    Résumé Question Je vois de plus en plus d’enfants et d’adolescents qui souffrent de céphalées pouvant se classer dans la catégorie des migraines. J’ai fait des lectures sur le sumatriptan par voie intranasale comme thérapie abortive. Est-ce un traitement efficace? Réponse La migraine aiguë chez les enfants et les adolescents est fréquente et difficile à traiter. Le sumatriptan intranasal est une option sûre et généralement efficace pour les enfants et les adolescents. La dose actuellement recommandée est de 20 mg pour les enfants qui pèsent plus de 40 kg et de 10 mg pour ceux dont le poids se situe entre 20 et 39 kg. Il faudrait faire des études de plus grande envergure pour contrecarrer les limitations des échantillons de petite taille et mieux comprendre la faible concentration plasmique et les effets placebo observés dans les études jusqu’à présent.

  15. Naines blanches : Les diamants sont éternels

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.

    1997-08-01

    Ces etoiles minuscules, composantes essentielles de la Galaxie, sont responsables de phenomenes spectaculaires, comme les novae ou certaines supernovae. Mais les naines blanches se sont aussi revelees un fantastique outil pour la physique du XXe siecle, fournissant des confirmations eclatantes de deux grandes theories: la relativite generale et la mecanique quantique.

  16. Les superpolynomes symetriques dans les problemes a plusieurs corps de la mecanique quantique supersymetrique

    NASA Astrophysics Data System (ADS)

    Desrosiers, Patrick

    S'inspirant de la supersymetrie, on construit dans cette these une nouvelle generalisation de la theorie des fonctions symetriques. Une theorie physique est supersymetrique si: (1) elle contient des bosons (particules de spin entier) et des fermions (particules de spin demi-entier); (2) elle reste inchangee suite a une transformation des bosons en fermions et vice versa. Les fonctions symetriques dans le superespace (superfonctions symetriques) incorporent a la fois des variables commutatives (bosoniques) et anticommutatives (fermioniques). Ces dernieres engendrent une algebre de Grassmann. Une superfonction symetrique est invariante sous l'echange simultane des variables bosoniques et fermioniques (action diagonale du groupe symetrique); elle se caracterise par une superpartition, i.e., une juxtaposition appropriee de partitions usuelles d'entiers non negatifs. On utilise deux approches dans l'elaboration de la theorie des superfonctions symetriques: l'une provient de la combinatoire et l'autre, de la physique. Suivant la premiere approche, on obtient l'extension des elements standards de la theorie des fonctions symetriques fonctions monomiales, fonctions symetriques elementaires, fonctions completement symetriques, series de puissances, fonctions generatrices et formules de Cauchy. On demontre egalement qu'il existe une extension naturelle, a un parametre, du produit scalaire combinatoire defini par l'orthogonalite des series de puissances dans le superespace. La seconde approche consiste a resoudre des problemes a N corps de la mecanique quantique supersymetrique. On etudie les extensions supersymetriques des modeles Calogero-Moser-Sutherland (CMS), lesquels decrivent l'evolution de particules dont le potentiel d'inter action est proportionnel a l'inverse du carre de la distance separant les particules. Deux modeles supersymetriques CMS sont resolus: trigonometrique (sur un cercle) et rationnel (sur une ligne) avec confinement harmonique. Leurs fonctions d

  17. Sol-gel processes and materials. January 1970-August 1988 (Citations from the US Patent data base). Report for January 1970-August 1988

    SciTech Connect

    Not Available

    1988-08-01

    This bibliography contains citations of selected patents concerning Sol-Gel processes and Sol-Gel derived materials and products. Selected patents include Sol-Gel compositions, ceramic and refractory materials, fabrication of silica glass, cataylsts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, Sol-Gel production of microspheres, Sol-Gel thin films and coatings, photographic materials, and dental materials. (Contains 71 citations fully indexed and including a title list.)

  18. Preparation of oxide glasses from metal alkoxides by sol-gel method

    NASA Technical Reports Server (NTRS)

    Kamiya, K.; Yoko, T.; Sakka, S.

    1987-01-01

    An investigation is carried out on the types of siloxane polymers produced in the course of the hydrolysis of silicon tetraethoxide, as well as the preparation of oxide glasses from metal alkoxides by the sol-gel method.

  19. Molecular receptors in metal oxide sol-gel materials prepared via molecular imprinting

    DOEpatents

    Sasaki, Darryl Y.; Brinker, C. Jeffrey; Ashley, Carol S.; Daitch, Charles E.; Shea, Kenneth J.; Rush, Daniel J.

    2000-01-01

    A method is provided for molecularly imprinting the surface of a sol-gel material, by forming a solution comprised of a sol-gel material, a solvent, an imprinting molecule, and a functionalizing siloxane monomer of the form Si(OR).sub.3-n X.sub.n, wherein n is an integer between zero and three and X is a functional group capable of reacting with the imprinting molecule, evaporating the solvent, and removing the imprinting molecule to form the molecularly imprinted metal oxide sol-gel material. The use of metal oxide sol-gels allows the material porosity, pore size, density, surface area, hardness, electrostatic charge, polarity, optical density, and surface hydrophobicity to be tailored and be employed as sensors and in catalytic and separations operations.

  20. Porous alumina scaffold produced by sol-gel combined polymeric sponge method

    NASA Astrophysics Data System (ADS)

    Hasmaliza, M.; Fazliah, M. N.; Shafinaz, R. J.

    2012-09-01

    Sol gel is a novel method used to produce high purity alumina with nanometric scale. In this study, three-dimensional porous alumina scaffold was produced using sol-gel polymeric sponge method. Briefly, sol gel alumina was prepared by evaporation and polymeric sponge cut to designated sizes were immersed in the sol gel followed by sintering at 1250 and 1550°C. In order to study the cell interaction, the porous alumina scaffold was sterilized using autoclave prior to Human Mesenchymal Stem Cells (HMSCs) seeding on the scaffold and the cell proliferation was assessed by alamarBlue® assay. SEM results showed that during the 21 day period, HMSCs were able to attach on the scaffold surface and the interconnecting pores while maintaining its proliferation. These findings suggested the potential use of the porous alumina produced as a scaffold for implantation procedure.

  1. Fabrication of ceramic microspheres by diffusion-induced sol-gel reaction in double emulsions.

    PubMed

    Zhang, Lei; Hao, Shaochang; Liu, Bing; Shum, Ho Cheung; Li, Jiang; Chen, Haosheng

    2013-11-27

    We demonstrate an approach to prepare zirconium dioxide (ZrO2) microspheres by carrying out a diffusion-induced sol-gel reaction inside double emulsion droplets. A glass capillary microfluidic device is introduced to generate monodisperse water-in-oil-in-water (W/O/W) double emulsions with a zirconium precursor as the inner phase. By adding ammonia to the continuous aqueous phase, the zirconium precursor solution is triggered to gel inside the emulsions. The double emulsion structure enhances the uniformity in the rate of the sol-gel reaction, resulting in sol-gel microspheres with improved size uniformity and sphericity. ZrO2 ceramic microspheres are formed following subsequent drying and sintering steps. Our approach, which combines double-emulsion-templating and sol-gel synthesis, has great potential for fabricating versatile ceramic microspheres for applications under high temperature and pressure. PMID:23865771

  2. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy.

    PubMed

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K; Li, Jiangyu; Zhou, Qifa

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films. PMID:23798771

  3. Influence of pyrogenic particles on the micromechanical behavior of thin sol-gel layers.

    PubMed

    Schönstedt, B; Garnweitner, G; Barth, N; Mühlmeister, A; Kwade, A

    2011-07-01

    Coatings based on sol-gel technology with different types of nanoparticles embedded into the sol-gel matrix were fabricated, and the resulting properties were investigated. Pyrogenic silica nanoparticles were added to the sol before coating. The silica particles varied in primary particle size and agglomerate size, and in their surface modification. The particles were wetted in ethanol and dispersed to certain finenesses. The difference in agglomerate size was partly caused by varying particle types, but also by the dispersing processes that were applied to the particles. The resulting coatings were examined by visual appearance and SEM microscopy. Furthermore, their micromechanical properties were determined by nanoindentation. The results show an important influence from the added nanoparticles and their properties on the visual appearance as well as the micromechanical behavior of the sol-gel coatings. It is shown that, in fact, the particle size distribution can have a major impact on the coating properties as well as the surface modification. PMID:21630652

  4. All optical controlled photonic integrated circuits using azo dye functionized sol-gel material

    NASA Astrophysics Data System (ADS)

    Ke, Xianjun

    The main focus of this dissertation is development and characterization of all-optical controllable azo dye functionized sol gel material, demonstrating a PIC fabrication technique on glass substrate using such material, and exploration and feasibility demonstration of three PIC functional devices namely optical variable attenuator, optical switches, and optical tunable filters using the material. The realization of all the devices in this dissertation are based on one material: dye functionalized sol-gel material. A photochromic sol-gel material functionalized with azo dye was synthesized and characterized. It possesses a photochromic characteristic under the control of green laser beam illumination. The material characteristics suggest the possibility of a new promising material platform candidate for the fabrication of alloptical controlled photonic integrated circuits. As the first potential application of the dye functionalized sol-gel material, an alloptical variable attenuator was designed and demonstrated. The optical variable attenuation is achieved in Mach-Zehnder interferometric configuration through all-optical modulation of sol-gel waveguide phase shifters. A 2 x 2 optical switch based on multimode interference (MMI) waveguide structure is proposed in the dissertation. The schematic configuration of the optical switch consists of a cascade of two identical MMIs with two all-optical controlled phase shifters realized by using the photochromic sol-gel material. The cross or bar switch state of the optical switch is determined by the phase difference between the two sol-gel waveguide phase shifters. An all-optical tunable filter is designed and its feasibility demonstrated by using the sol-gel photochromic material. Except for the phase change demonstrated on sol-gel waveguide phase shifters, dynamic gratings were observed on sol-gel film when exposed to two interference beams. This reveals the possibility of realizing Bragg grating-based tunable filters

  5. LES of propelled bodies in crashback

    NASA Astrophysics Data System (ADS)

    Kumar, Praveen; Mahesh, Krishnan

    2015-11-01

    Crashback is an off-design operating condition to quickly stop a propelled vehicle by rotating the propeller in reverse direction, thus yielding a negative thrust. The interaction of the freestream with the strong reverse flow from the propeller creates massive unsteadiness and flow separation. This talk will discuss our work towards simulation of crashback flow over an entire hull using Large-Eddy Simulation (LES).The results will be compared to the available experimental data and the flow physics will be discussed. The flowfield of the hull-attached propeller in crashback will be analyzed using dynamic mode decomposition to understand the mechanism of the unsteady loads. This work is supported by the Office of Naval Research.

  6. Durable flame retardant finish for silk fabric using boron hybrid silica sol

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang; Xing, Tie-ling

    2016-11-01

    A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H3BO3) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated samples obviously decreased.

  7. Study of near scrape-off layer (SOL) temperature and density gradient lengths with Thomson scattering

    NASA Astrophysics Data System (ADS)

    Sun, H. J.; Wolfrum, E.; Eich, T.; Kurzan, B.; Potzel, S.; Stroth, U.; the ASDEX Upgrade Team

    2015-12-01

    Improvements to the Thomson scattering diagnostic have enabled the study of near scrape-off layer (SOL) decay lengths in the 2014 ASDEX Upgrade experimental campaign. A database of H-mode discharges has been studied using a two-line fit method for the core and log-linear fit for the near SOL region under both attached and detached divertor conditions. SOL electron temperature {{T}e} profiles have been found to have a radial exponential decay distribution which does not vary poloidally, consistent with the two-point model. In attached H-mode regimes, a log-linear regression shows that the SOL upstream dataset has the same main parametric dependencies as the scaling inferred from downstream Infrared camera measurements. A simple collisional relation from two-point model is found to best relate the upstream decay lengths and downstream divertor power widths. The SOL {{T}e} gradient length appears to be independent of {{T}e} pedestal parameters, but may correlate with the pedestal electron pressure parameters. Both the pedestal and SOL density and temperature scale lengths are linearly correlated with an almost constant gradient ratio, {ηe} . The smaller gradient ratio {ηe} and the fact that the Spitzer-Härm model is more valid, agrees with the studied plasma lying in the collisional regime. A transition to flat SOL ne profiles, previously reported for L-mode plasmas in many machines, has been observed in AUG detatched H-mode regimes. When the flattening of density profile happens in H-mode detached plasmas, the broadening of near SOL {{T}e} decay length {λ{{Te,u}}} also appears which may be good news for future machines.

  8. Strength of interactions between immobilized dye molecules and sol-gel matrices.

    PubMed

    Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

    2011-02-21

    In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel. PMID:21120245

  9. Solid-state tunable lasers based on dye-doped sol-gel materials

    SciTech Connect

    Dunn, B.; Mackenzie, J.D.; Zink, J.I.; Stafsudd, O.M.

    1992-03-01

    The sol-gel process is a solution synthesis technique which provides a low temperature chemical route for the preparation of rigid transparent matrix materials. The luminescent organic dye molecules, rhodamine 6G and coumarin 540A have been incorporated, via the sol-gel method, into aluminosilicate and organically modified silicate host matrices. Synthesis, laser oscillation and photostability for these systems are reported. The improved photostability of these materials with respect to comparable polymeric host materials is discussed.

  10. Making MgO/SiO2 Glasses By The Sol-Gel Process

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1989-01-01

    Silicon dioxide glasses containing 15 mole percent magnesium oxide prepared by sol-gel process. Not made by conventional melting because ingredients immiscible liquids. Synthesis of MgO/SiO2 glass starts with mixing of magnesium nitrate hexahydrate with silicon tetraethoxide, both in alcohol. Water added, and transparent gel forms. Subsequent processing converts gel into glass. Besides producing glasses of new composition at lower processing temperatures, sol-gel method leads to improved homogeneity and higher purity.

  11. Overview Of 100 Sols Of Chemcam Operations At Gale Crater

    NASA Astrophysics Data System (ADS)

    Maurice, Sylvestre; Wiens, Roger; MSL Science Team

    2013-04-01

    The Curiosity rover carries the ChemCam instrument suite, a Laser-Induced Breakdown Spectroscopy (LIBS) instrument that can analyze the chemical composition of geological samples at distances up to 7 meters from the rover, and a high resolution camera for context imaging (RMI). In the first 100 sols after landing, ChemCam performed 343 single point measurements on approximately 50 different rocks or soil areas, for over 12,000 laser shots. Each time at least two RMI images are acquired before and after the laser shots to visualize the area of investigation and the geological context. LIBS lines are identified using primarily a martian dedicated database; to date, ChemCam has detected unambiguously major elements (Si, Al, Fe, Mg, Ca, Na, K, O), minor/trace elements of interest (Li, Cr, Mn, Rb, Sr, Ba, Ti, S, C, H). These observations allow a qualitative/quantitative assessment of the presence of dust (first few shots), the sample surface composition and chemical heterogeneity with depth. Several techniques have been developed to analyze ChemCam's data: (1) Univariate analysis refers to peak height studies of well-chosen LIBS lines and a training dataset to build calibration curves. Peak ratios K/Si, Na/Si, Al/Si, Fe+Mg/Si, or Mg/Mg+Fe have been calculated from the onboard calibration targets. The technique also applies to minor and trace elements which yield low intensity emission lines, such as Lin, Rb, H, C. (2) Multivariate methods give better results in terms of elemental composition, since they examine simultaneously and statistically several peaks of the same elements. A Partial Least Squares (PLS) regression algorithm is used for rapid major-element abundance determination. (3) Composition trends, clusters and end-members can also be identified using component analysis methods. Independent Component Analysis (ICA) identifies components that are directly related to Chemical elements: Al, Ca, Fe, H, K, Mg, Na, O, Si, Ti, but also mixture like a "soil" component

  12. Rationale and Design of the Echocardiographic Study of Hispanics / Latinos (ECHO-SOL)

    PubMed Central

    Rodriguez, Carlos J.; Dharod, Ajay; Allison, Matthew A.; Shah, Sanjiv J.; Hurwitz, Barry; Bangdiwala, Shrikant I.; Gonzalez, Franklyn; Kitzman, Dalane; Gillam, Linda; Spevack, Daniel; Dadhania, Rupal; Langdon, Sarah; Kaplan, Robert

    2015-01-01

    Background Information regarding the prevalence and determinants of cardiac structure and function (systolic and diastolic) among the various Hispanic background groups in the United States is limited. Methods and Results The Echocardiographic Study of Latinos (ECHO-SOL) ancillary study recruited 1,824 participants through a stratified-sampling process representative of the population-based Hispanic Communities Health Study – Study of Latinos (HCHS-SOL) across four sites (Bronx, NY; Chicago, Ill; San Diego, Calif; Miami, Fla). The HCHS-SOL baseline cohort did not include an echo exam. ECHO-SOL added the echocardiographic assessment of cardiac structure and function to an array of existing HCHS-SOL baseline clinical, psychosocial, and socioeconomic data and provides sufficient statistical power for comparisons among the Hispanic subgroups. Standard two-dimensional (2D) echocardiography protocol, including M-mode, spectral, color and tissue Doppler study was performed. The main objectives were to: 1) characterize cardiac structure and function and its determinants among Hispanics and Hispanic subgroups; and 2) determine the contributions of specific psychosocial factors (acculturation and familismo) to cardiac structure and function among Hispanics. Conclusion We describe the design, methods and rationale of currently the largest and most comprehensive study of cardiac structure and function exclusively among US Hispanics. ECHO-SOL aims to enhance our understanding of Hispanic cardiovascular health as well as help untangle the relative importance of Hispanic subgroup heterogeneity and sociocultural factors on cardiac structure and function. (Ethn Dis. 2015;25[2]:180–186) PMID:26118146

  13. Preparation and characterization of conductive and transparent ruthenium dioxide sol-gel films.

    PubMed

    Allhusen, John S; Conboy, John C

    2013-11-27

    RuO2 conductive thin films were synthesized using the sol-gel method and deposited onto transparent insulating substrates. The optical transmission, film thickness, surface morphology and composition, resistivity, and spectroelectrochemical performance have been characterized. The optical transmission values of these films ranged from 70 to 89% in the visible region and from 56 to 88% in the infrared region. Resistivity values of the RuO2 sol-gel films varied from 1.02 × 10(-3) to 1.13 Ω cm and are highly dependent on the initial solution concentration of RuO2 in the sol-gel. The RuO2 sol-gel films were used as electrodes for the electrochemical oxidation and reduction of ferrocenemethanol. The electrochemical behavior of our novel RuO2 sol-gel films was compared to that of a standard platinum disk electrode and showed no appreciable differences in the half-wave potential (E1/2). The mechanical and chemical stability of the coatings was tested by physical abrasion and exposure to highly acidic, oxidizing Piranha solution. Repeated exposure to these extreme conditions did not result in any appreciable decline in electrochemical performance. Finally, the use of the novel RuO2 sol-gel conductive and transparent films was demonstrated in a spectroelectrochemistry experiment in which the oxidation and reduction of ferrocenemethanol was monitored via UV-vis spectroscopy as the applied potential was cycled. PMID:24221640

  14. Luminescence behavior of terbium sulphosalicylic acid complexes in sol-gel derived host materials

    SciTech Connect

    Fan, X.; Wang, M.; Wang, Z.; Hong, Z.

    1997-08-01

    The formation and luminescence behavior of terbium sulphosalicylic acid (TbSSA) complexes in sol-gel derived host materials have been investigated. The 5-sulphosalicylic acid (H{sub 3}SSA) was dissolved in ethanol in advance, and then the TbCl{sub 3} and ethanol containing H{sub 3}SSA were introduced into the initial precursor sol, respectively. The resulting sol exhibits intramolecular energy transfer from the coordinated sulphosalicylic acid to the terbium ion. The TbSSA complex has formed in the TbCl{sub 3} and H{sub 3}SSA codoped sol. The complexes were found to have notably higher fluorescence intensities than TbCl{sub 3} in both the sol and the gel. In the sol, the concentration quenching was a diffusion-controlled process due to aggregation and effective collision between molecules and the fluorescence was decreased with increase of H{sub 3}SSA concentration. On the other hand, the molecules in the gel were isolated in the pores of the silica network. The fluorescence intensities of TbSSA in the gel were increased with the increase of concentration ratio of H{sub 3}SSA/TbCl{sub 3}. Maximum fluorescence intensity was obtained at H{sub 3}SSA/TbCl{sub 3} = 2.

  15. [Sol-gel preparation of ultrathin nano-hydroxyapatite coating and its characterization].

    PubMed

    Yang, Jianhua; Guo, Linghong; Li, Hui

    2006-10-01

    Present study used dip-coating techniques to fabricate ultrathin nano-HA coating on titanium in organic sol-gel of Ca (NO3)2. 4H2O and PO(CH3)3 and inorganic sol-gel of Ca (NO3)2. 4H2O and (NH4)2HPO4. Scanning electron microscope (SEM) and grazing-incidence X-ray diffraction (XRD) were used to observe the morphology and distribution of crystallite size (D) and lattice strain (epsilon) of ultrathin nano-HA coating. After heated at 400 degrees C, the apatite structure of coatings on titanium began to appear. At heating temperature of 400 degrees C-600 degrees C, the effect of heating temperature on D and epsilon of both coatings was obvious. Precursor types significantly affected the particle diameters of nano-HA coatings, which were 25-40 nm for organic sol-gel and about 100 nm for inorganic sol. The thickness of ultrathin nano-HA coatings was 2.5 microm for organic sol-gel and 5 microm for inorganic sol and morphology of interfaces between coating and titanium was intact and homogenous. PMID:17121358

  16. Investigation of optical properties of anthocyanin doped into sol-gel based matrix

    NASA Astrophysics Data System (ADS)

    Hashim, Hasrina; Abdul Aziz, Nik Mohd Azmi Nik; Isnin, Aishah

    2012-06-01

    Anthocyanin dye was extracted from petal of Hibiscus rosasinensis (Bunga Raya) and doped into sol-gel based matrix to investigate an effect of pH change on its optical properties. Sol-gel matrix based on Vinyl triethoxysilene (VTES) as a precursor was prepared through Sol-gel process at pH 7. The sol was doped with 0.1% of Anthocyanin and the same amount of dye was also dissolved in ethanol as a comparative sample. Hydrochloric Acid, HCl and Tetramethylammonium Hydroxide, TMAH were used to change the pH value by adding them at various concentrations into each sample. The emission spectra and chemical structures of the samples were measured by Spectrofluorometer and Fourier Transform Infrared (FTIR) respectively. When excited at 410 nm, two emission peaks at about 492 and 574 nm were observed for Anthocyanin in acidic environment both in ethanol and VTES sol. In base environment however, only Anthocyanin dissolved in ethanol produced emission peak with a single peak at about 539 nm. The sensitivity of Anthocyanin dye toward pH changes in VTES open a possibility to use it as sensing element in which sol-gel based matrix are known to have higher mechanical strength and thermal stability.

  17. Sol-gel derived ZnO thin films: Effect of amino-additives

    NASA Astrophysics Data System (ADS)

    Hosseini Vajargah, P.; Abdizadeh, H.; Ebrahimifard, R.; Golobostanfard, M. R.

    2013-11-01

    Zinc oxide thin films were dip-coated from an alcoholic sol of zinc acetate with different amino-additives including monoethanolamine, diethanolamine, triethanolamine, triethylamine, and ethylenediamine. Sol-gel behavior, crystal structure, optoelectronic and morphological properties of thin films were investigated with focus on the effects of different amines and drying conditions. Investigations explicate the role of chemical and physical properties of amines such as organic chains, polarity, and boiling point as the main factors that cause distinct sol-gel behavior and film properties. It is shown that different amines in different molar ratios together with drying temperature cause dramatic impacts on sol transparency, stability, and consequently on structural, optoelectronic, and morphological properties of films. Notably, monoethanolamine and triethylamine films demonstrate a preferred orientation stimulated by increased molar ratio of amines. Further investigations indicated the positive effect of elevated drying temperature particularly on those films prepared from sols with high-boiling-point stabilizers. The variation of film optoelectronics seems to depend mainly on heat treatment, whereas sol chemistry influences the optical properties indirectly through the structural alteration. Peculiar morphologies in the ethylenediamine films disappeared with adjusting the drying conditions. The size of ZnO grains were approximately independent of amine types and primarily affected by the heat treatment

  18. Thermosensitive periodontal sol of ciprofloxacin hydrochloride and serratiopeptidase: Pharmaceutical and mechanical analysis

    PubMed Central

    Singh, Kushal Pal; Chhabra, Gulshan; Sharma, Vijay; Pathak, Kamla

    2014-01-01

    Aim: The aim of the present work was to explore the development of a dual-controlled release periodontal system of a potent broad spectrum first-generation fluoroquinolone, ciprofloxacin, and the anti-inflammatory enzyme serratiopeptidase (STP). Materials and Methods: Based on 32 full factorial design, thermoreversible periodontal sols capable of controlled dual delivery of ciprofloxacin hydrochloride and STP were designed using pluronic F127 and carbopol 934P as thermosensitive gelling polymers. Sol gel transition characteristics, %cumulative drug release at 48th h and exvivo mucoadhesive strength were designated as dependent responses. The sols were mucoadhesive, syringeable, and inverted into gels at simulated periodontal cavity temperature. Results: F9 with optimal drug release was identified as the best formulation. Extra design check point generated using Design Expert software 8.02 (Stat-Ease, USA) validated the experimental design. Textural analysis revealed that the developed sols were syringeable and spreadable enough for periodontal treatment so it can be expected that hardness and compressibility of sols would pose no problem during clinical application. The in vitro release behavior exhibited controlled release of both cipro HCl and STP (>90% release). Conclusion: A dual-controlled release thermoreversible periodontal sol of ciproflaxin and STP was successfully developed. Incorporation of STP as anti-inflammatory agent has the potential of developing a therapeutically efficacious system of cipro HCl for treatment of periodontal inflammatory anaerobic infections. PMID:24678456

  19. One-step sol-gel imprint lithography for guided-mode resonance structures

    NASA Astrophysics Data System (ADS)

    Huang, Yin; Liu, Longju; Johnson, Michael; Hillier, Andrew C.; Lu, Meng

    2016-03-01

    Guided-mode resonance (GMR) structures consisting of sub-wavelength periodic gratings are capable of producing narrow-linewidth optical resonances. This paper describes a sol-gel-based imprint lithography method for the fabrication of submicron 1D and 2D GMR structures. This method utilizes a patterned polydimethylsiloxane (PDMS) mold to fabricate the grating coupler and waveguide for a GMR device using a sol-gel thin film in a single step. An organic-inorganic hybrid sol-gel film was selected as the imprint material because of its relatively high refractive index. The optical responses of several sol-gel GMR devices were characterized, and the experimental results were in good agreement with the results of electromagnetic simulations. The influence of processing parameters was investigated in order to determine how finely the spectral response and resonant wavelength of the GMR devices could be tuned. As an example potential application, refractometric sensing experiments were performed using a 1D sol-gel device. The results demonstrated a refractive index sensitivity of 50 nm/refractive index unit. This one-step fabrication process offers a simple, rapid, and low-cost means of fabricating GMR structures. We anticipate that this method can be valuable in the development of various GMR-based devices as it can readily enable the fabrication of complex shapes and allow the doping of optically active materials into sol-gel thin film.

  20. Sol gel growth of titania from electrospun polyacrylonitrile nanofibres

    NASA Astrophysics Data System (ADS)

    Hong, Youliang; Li, Domgmei; Zheng, Jian; Zou, Guangtian

    2006-04-01

    In this paper we report on the development of TiO2 surface-residing electrospun nanofibres with controllable density of TiO2 on the support fibre surface by means of an electrospinning technique and a sol-gel process. The TiO2 precursor/PAN composite nanofibres were synthesized by electrospinning a polyacrylonitrile (PAN) solution containing TiO2 precursors. Subsequently, an immersion of the electrospun composite nanofibres in deionized water led to the hydrolysis of the TiO2 precursors. SEM, TEM and XRD pattern analyses demonstrated that TiO2 was formed and resided on the nanofibre surface. On further calcining the hydrolysed nanofibres in air at 300 °C, TiO2 could be conveniently converted into anatase without essentially changing the morphology of the hydrolysed nanofibres. Furthermore, surface photovoltage spectroscopy (SPS) confirmed that the TiO2 surface-residing nanofibre nonwovens had a strong SPS response. It can be attributed that the surface residence of TiO2 permits the transfer of the photogenerated electron originating from TiO2 to ITO electrodes. Potential applications of the TiO2 surface-residing nanofibres include filters, catalysis films and environmental pollution remediation films.

  1. /dopamine films prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Valverde-Aguilar, G.; Prado-Prone, G.; Vergara-Aragón, P.; Garcia-Macedo, J.; Santiago, Patricia; Rendón, Luis

    2014-09-01

    Dopamine was encapsulated into nanoporous amorphous TiO2 matrix by sol-gel method under atmospheric conditions. A second sample was obtained by the addition of the crown-ether 15C5 in this previous sample. Thin films were spin-coated on glass wafers. No heat treatment was employed in both films. All films were characterized using infrared spectroscopy, high resolution transmission electronic microscopy, X-ray diffraction, optical absorption and scanning electronic microscopy. Despite the films prepared with 15C5 were no calcined, a partial crystallization was identified. Anatase and rutile nanoparticles with sizes of 4-5 nm were obtained. Photoconductivity technique was used to determine the charge transport mechanism on these films. Experimental data were fitted with straight lines at darkness and under illumination wavelengths at 320, 400, and 515 nm. It indicates an ohmic behavior. Photovoltaic and photoconductivity parameters were determined from the current density vs. the applied-electrical-field results. Amorphous film has bigger photovoltaic and photoconductive parameters than the partially crystalline film. Results observed in the present investigation prove that the nanoporous TiO2 matrix can protect the dopamine inhibiting its chemical instability. This fact modifies the optical, physical and electrical properties of the film, and is intensified when 15C5 is added.

  2. Modeling of far SOL plasma transport in NSTX

    SciTech Connect

    Sergei Krasheninnikov; Alexander Pigarov

    2005-11-02

    For better understanding and characterization of non-diffusive transport occurring in the NSTX tokamak edge plasma, we performed extensive simulations of NSTX edge plasmas with the multi-fluid two-dimensional UEDGE code by using realistic model for impurity sputtering sources and hybrid model for anomalous cross-field transport. Our cross-field transport model incorporates the effects of non-diffusive intermittent transport by introducing anomalous convective velocities whose spatial profile is adjusted for each ion charge state to match available experimental data. The research in 2002-2005 financial years was focused on the following areas: (i) development of capabilities for UEDGE simulation of NSTX spectroscopy data (i.e., the 3D real-geometry postprocessor UEDGE tools for comparison between UEDGE and experimental data), (ii) simulation of multi-diagnostic data from NSTX with UEDGE, (iii) study of anomalous cross-field convective transport of impurity ions, (iv) analysis of divertor plasma opacity to resonance radiation, and (v) study the effects of ballooning-like anomalous cross-field transport and spherical-torus magnetic configuration on parallel plasma flows in the SOL.

  3. Wide-Angle View of Gusev Dust Devil, Sol 559

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows dust devils moving across the plain inside Mars' Gusev Crater, as seen with a hazard-identification camera on NASA's Mars Exploration Rover Spirit. The clip consists of consists of frames taken by that camera during a span of 8 minutes, 26 seconds on the rover's 559th martian day, or sol (July 29, 2005). Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust moved by wind.

    Spirit began seeing dust devil activity around the beginning of Mars' spring season. Activity increased as spring continued, but fell off again for about two weeks during a dust storm. As the dust storm faded away, dust devil activity came back. In the mid-afternoons as the summer solstice approached, dust devils were a very common occurrence on the floor of Gusev crater. The early-spring dust devils tended to move southwest-to-northeast, across the dust devil streaks in Gusev seen from orbit. Increasingly as the season progresses, the dust devils are seen moving northwest-to-southeast, in the same direction as the streaks. Scientists are watching for the big dust devils that leave those streaks.

  4. Sol-gel template synthesis of semiconductor nanostructures

    SciTech Connect

    Lakshmi, B.B.; Dorhout, P.K.; Martin, C.R.

    1997-03-01

    The template method for preparing nanostructures entails synthesis of the desired material within the pores of a nanoporous membrane or other solid. A nonofibril or tubule of the desired material is obtained within each pore. Methods used previously to deposit materials within the pores of such membranes include electrochemical and electroless deposition and in situ polymerization. This paper describes the first use of sol-gel chemistry to prepare semiconductor nanofibrils and tubules within the pores of an alumina template membrane. TiO{sub 2}, WO{sub 3}, and ZnO nanostructures have been prepared. TiO{sub 2} nanofibrils with diameters of 22 nm were found to be single crystals of anatase with the c-axis oriented along the fibril axis. Bundles of these fibrils were also found to be single crystalline, suggesting that the individual fibrils are arranged in a highly organized fashion within the bundle. Finally, 200 nm diameter TiO{sub 2} fibrils were used as photocatalysts for the decomposition of salicylic acid. 30 refs., 8 figs.

  5. Feeding by Actinophrys sol (Protista, Heliozoa): 1 light microscopy.

    PubMed

    Patterson, D J; Hausmann, K

    1981-01-01

    The feeding behavior of the heliozoon Actinophrys sol was investigated using the ciliate Colpidium colpoda as food. The ciliate is caught by adhesion to the arms of the heliozoon. Within 20 min the prey is enclosed by a funnel-shaped pseudopodium which progresses over the prey by the action of its differentiated leading edge. Independent Actinophrys cells may fuse together during prey capture and the early stages of prey digestion. After prey ingestion, the ciliate is lysed and the contents of the food vacuole coagulate. Much of the fluid is removed from the food vacuole and, within 4 h of feeding, the food vacuole has condensed around its coagulated contents. As food vacuole condensation occurs, the peripheral region of the heliozoon cell becomes vacuolated. The appearance of the cell and of the food vacuole remain the same for about 12 h, after which time the undigested residues in the food vacuoles are egested, fused masses of cells separate as uninucleate cells and nuclear division may occur. During feeding, the extrusomes are greatly depleted. These bodies are implicated in the processes of food capture and in the production of food vacuole membrane. PMID:7311876

  6. True Color of Mars - Pathfinder Sol 10 at noon

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The true color of Mars based upon three filters with the sky set to aluminance of 60. The color of the Pathfinder landing site is yellowish brown with only subtle variations. These colors are identical to the measured colors of the Viking landing sites reported by Huck et al. [1977]. This image was taken near local noon on Sol 10. A description of the techniques used to generate this color image from IMP data can be found in Maki et al., 1999. Note: a calibrated output device is required accurately reproduce the correct colors.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  7. True Color of Mars - Pathfinder Sol 24 at 4 PM

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The brownish gray sky as it would be seen by an observer on Mars in this four-frame, true color mosaic taken on sol 24 (at approximately 1610 LST). The twin peaks can be seen on the horizon. The sky near the sun is a pale blue color. Azimuth extent is 60o and elevation extent is approximately 12odegrees. A description of the techniques used to generate this color image from IMP data can be found in Maki et al., 1999 (see full reference in Image Note). Note: a calibrated output device is required accurately reproduce the correct colors.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal investigator.

  8. Sol-gel-derived waterproof coating for laser glass

    NASA Astrophysics Data System (ADS)

    Jiang, Zhonghong; Hu, Lili; Song, Xiuyu

    1997-12-01

    A two layer coating was deposited by sol-gel dip-coating method on phosphate laser glass. First silica film was coated from SiO2 colloidal suspension derived from ammonia catalyzed hydrolysis of tetraethoxysilane in ethanol. Then a methyl containing silicate film was covered. It was fabricated from a solution prepared by the hydrolysis of methyltriethoxysilane in the presence of hydrogen chloride catalyst. A 130 degree(s)C, 16h heat-treatment was done after coating process. It is confirmed by optical microscope that the two layer coating improves obviously the chemical durability of phosphate laser glass. The laser damage threshold of this coating is measured to be 31 J/cm2 at 1060 nm wavelength of 10 ns pulse duration. It is found that silica film contributes to the improvement on both film adhesion to phosphate glass substrate and laser damage threshold of film. The methyl containing silicate single film has only 18 J/cm2 laser damage threshold and can be easily dissolved in ethanol solution when it was coated on the phosphate laser glass substrate.

  9. Characterization of titanium and zirconium valerate sol-gel films

    SciTech Connect

    Severin, K.G.; Ledford, J.S.; Torgerson, B.A.; Berglund, K.A. )

    1994-07-01

    FTIR and XPS have been used to characterize titanium and zirconium valerate thin films prepared using sol-gel techniques. Films were prepared by hydrolysis of titanium(IV) isopropoxide or zirconium(IV) n-propoxide in excess valeric acid at room temperature. Film solution chemistry, from precursors to cast films, was followed with FTIR. The structure and chemical composition of films spin cast from fresh and day-old solutions were determined. Results of these studies suggest that all films consist of a metal-oxygen polymer backbone coordinated with bidentate valerate ligands. No evidence for the presence of alkoxide ligands has been found. A small amount of water is present in all cast films. While solution aging experiments indicate that the zirconium film structure does not change with solution reaction time, carboxylate ligand concentrations are higher in titanium films made from aged solutions. Titanium films made from aged solutions contain slightly less than 1.5 valerate ligands/titanium atom. Zirconium films are more highly carboxylated with almost two valerate groups per metal center. 57 refs., 6 figs., 1 tab.

  10. Several Dust Devils in Gusev Crater, Sol 461

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the 21 frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 461st martian day, or sol (April 20, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  11. After Attempted Sample Delivery on Sol 60, False Color

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This view from the Surface Stereo Imager on NASA's Phoenix Mars Lander on the mission's 60th Martian day, or sol, (July 26, 2008) was taken after the lander's scoop sprinkled a soil sample over Thermal and Evolved-Gas Analyzer (TEGA).

    The upper part of the picture shows the robotic arm scoop parked open-face down above the TEGA after delivery. The TEGA doors farthest to the right were open to receive the sample into one of TEGA's eight ovens. Not enough material reached the oven to allow an analysis to begin. Some of the soil sample can be seen at the bottom of the adjacent pair of doors.

    This view is presented in false color, which makes the reddish color of the soil-sample material easy to see.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. Wind-Sculpted Vicinity After Opportunity's Sol 1797 Drive (Stereo)

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11820 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11820

    NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings just after driving 111 meters (364 feet) on the 1,797th Martian day, or sol, of Opportunity's surface mission (Feb. 12, 2009). North is at the center; south at both ends.

    This view is the right-eye member of a stereo pair presented as a cylindrical-perspective projection with geometric seam correction.

    Tracks from the drive recede northward across dark-toned sand ripples in the Meridiani Planum region of Mars. Patches of lighter-toned bedrock are visible on the left and right sides of the image. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches).

    This view is presented as a cylindrical-perspective projection with geometric seam correction.

  13. Synthesis of Carbon Nanotubes Using Sol Gel Route

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, Tarek

    2002-12-01

    Since 1990, carbon nanotubes were discovered and they have been the object of intense scientific study ever since. A carbon nanotube is a honeycomb lattice rolled into a cylinder. The diameter of a carbon nanotube is of nanometer size and the length is in the range of micrometer. Many of the extraordinary properties attributed to nanotubes, such as tensile strength and thermal stability, have inspired predictions of microscopic robots, dent-resistant car bodies and earthquake-resistant buildings. The first products to use nanotubes were electrical. Some General Motors cars already include plastic parts to which nanotubes were added; such plastic can be electrified during painting so that the paint will stick more readily. Two nanotube-based lighting and display products are well on their way to market. In the long term, perhaps the most valuable applications will take further advantage of nanotubes' unique electronic properties. Carbon nanotubes can in principle play the same role as silicon does in electronic circuits, but at a molecular scale where silicon and other standard semiconductors cease to work. There are several routes to synthesize carbon nanotubes; laser vaporization, carbon arc and vapor growth. We have applied a different route using sol gel chemistry to obtain carbon nanotubes. This work is patent-pending.

  14. Fast-wave Power Flow Along SOL Field Lines In NSTX nd The Associated Power Deposition Profile Across The SOL In Front Of The Antenna

    SciTech Connect

    Perkins, Roy

    2013-06-21

    Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divertor, albeit with a portion of the heat outside of the predictions. The field-line mapping can then be used to partially reconstruct the profile of lost fast-wave power at the midplane in front of the antenna, and the losses peak close to the last closed flux surface (LCFS) as well as the antenna. This profile suggests a radial standing-wave pattern formed by fast-wave propagation in the SOL, and this hypothesis will be tested on NSTX-U. Advanced RF codes must reproduce these results so that such codes can be used to understand this edge loss and to minimize RF heat deposition and erosion in the divertor region on ITER.

  15. Effects of sol concentration on structural, morphological and optical waveguiding properties of sol-gel ZnO nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Tazerout, Mohand; Chelouche, Azeddine; Touam, Tahar; Djouadi, Djamel; Boudjouan, Fares; Khodja, Sebti; Ouhenia, Salim; Fischer, Alexis; Boudrioua, Azzedine

    2014-07-01

    Nanostructured ZnO thin films with different precursor concentrations (0.5-0.8 M) have been deposited on glass substrates by sol-gel dip coating technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-visible spectrophotometer, and m-lines spectroscopy have been employed to investigate the effect of solution concentration on structural, morphological, optical and waveguiding properties of the ZnO thin films. XRD spectra have shown that all the films are polycrystalline and exhibit the wurtzite hexagonal structure. SEM micrographs and AFM images have revealed that morphology and surface roughness of the thin films depend on sol concentration. The UV-visible transmittance results show a high transparency in the visible range and a shift of the maximum transmittance to the higher wavelength with increasing sol concentration. Waveguiding properties such as refractive index, number of propagating modes and attenuation coefficient measured at 632.8 nm wavelength by m-lines spectroscopy indicate that our ZnO slab waveguides are single mode and demonstrate optical losses estimated around 1.5 decibel per cm (dB/cm) for the thin film prepared with a sol concentration of 0.7 M.

  16. Effect of different sol concentrations on the properties of nanocrystalline ZnO thin films grown on FTO substrates by sol-gel spin-coating

    NASA Astrophysics Data System (ADS)

    Kim, Ikhyun; Kim, Younggyu; Nam, Giwoong; Kim, Dongwan; Park, Minju; Kim, Haeun; Lee, Wookbin; Leem, Jae-Young; Kim, Jong Su; Kim, Jin Soo

    2014-08-01

    Nanocrystalline ZnO thin films grown on fluorine-doped tinoxide (FTO) substrates were fabricated using the spin-coating method. The structural and the optical properties of the ZnO thin films prepared using different sol concentrations were investigated by using field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), photoluminescence (PL) measurements, and ultraviolet-visible (UV-vis) spectrometry. The surface morphology of the ZnO thin films, as observed in the SEM images, exhibited a mountain-chain structure. XRD results indicated that the thin films were preferentially orientated along the direction of the c-axis and that the grain size of the ZnO thin films increased with increasing sol concentration. The PL spectra showed a strong ultraviolet emission peak at 3.22 eV and a broad orange emission peak at 2.0 eV. The intensities of deep-level emission (DLE) gradually increased with increasing sol concentration from 0.4 to 1.0 M. The transmittance spectra of the ZnO thin films showed that the ZnO thin films were transparent (~85%) in the visible region and exhibited sharp absorption edges at 375 nm. Thus, The Urbach energy of ZnO thin films decreased with increasing sol concentration.

  17. Numerical and physical instabilities in massively parallel LES of reacting flows

    NASA Astrophysics Data System (ADS)

    Poinsot, Thierry

    LES of reacting flows is rapidly becoming mature and providing levels of precision which can not be reached with any RANS (Reynolds Averaged) technique. In addition to the multiple subgrid scale models required for such LES and to the questions raised by the required numerical accurcay of LES solvers, various issues related the reliability, mesh independence and repetitivity of LES must still be addressed, especially when LES is used on massively parallel machines. This talk discusses some of these issues: (1) the existence of non physical waves (known as `wiggles' by most LES practitioners) in LES, (2) the effects of mesh size on LES of reacting flows, (3) the growth of rounding errors in LES on massively parallel machines and more generally (4) the ability to qualify a LES code as `bug free' and `accurate'. Examples range from academic cases (minimum non-reacting turbulent channel) to applied configurations (a sector of an helicopter combustion chamber).

  18. Sol-gel synthesis and characterization of nanostructured TiO2/gamma-Al2O3 composite membranes.

    PubMed

    Kwon, Hyuk Taek; Kim, Jinsoo

    2011-08-01

    Nanostructured TiO2/gamma-Al2O3 composite membranes with various compositions were prepared by sol-gel method. The structural and textural properties of the composite membranes could be modified by the mixing ratio of boehmite sol and titania sol, and calcination temperature. The existence of alumina in the composite membranes retarded anatase-to-rutile phase transformation, resulting in stabilization of textural properties. Defect-free composite membranes were confirmed by gas permeation test. PMID:22103175

  19. Updrafts, Downdrafts, Entrainment, and Detrainment in the Giga-LES

    NASA Astrophysics Data System (ADS)

    Krueger, S. K.; Glenn, I.

    2012-12-01

    We are investigating the properties of evolving three-dimensional updraft and downdraft "cores" in a model dataset from the Giga-LES, a large-domain LES (large-eddy simulation) of tropical oceanic deep convection (Khairoutdinov et al. 2009). We have also applied the analysis method developed by Kuang and Bretherton (2006) to investigate various aspects of the ensemble characteristics of cumulus convection in the Giga-LES. Our results agree with those of Kuang and Bretherton for the cumulus updraft properties. We have examined the relative merits of different entrainment and cloud-top-height assumptions in spectral plume models of cumulus updrafts, the characteristics of downdrafts, and the nature of a rapid transition from shallow to deep convection.isualization of cumulus clouds from the Giga-LES. The realistic structure is associated with entrainment.

  20. Entrapment of subtilisin in ceramic sol-gel coating for antifouling applications.

    PubMed

    Regina, Viduthalai Rasheedkhan; Søhoel, Helmer; Lokanathan, Arcot Raghupathi; Bischoff, Claus; Kingshott, Peter; Revsbech, Niels Peter; Meyer, Rikke Louise

    2012-11-01

    Enzymes with antifouling properties are of great interest in developing nontoxic antifouling coatings. A bottleneck in developing enzyme-based antifouling coatings is to immobilize the enzyme in a suitable coating matrix without compromising its activity and stability. Entrapment of enzymes in ceramics using the sol-gel method is known to have several advantages over other immobilization methods. The sol-gel method can be used to make robust coatings, and the aim of this study was to explore if sol-gel technology can be used to develop robust coatings harboring active enzymes for antifouling applications. We successfully entrapped a protease, subtilisin (Savinase, Novozymes), in a ceramic coating using a sol-gel method. The sol-gel formulation, when coated on a stainless steel surface, adhered strongly and cured at room temperature in less than 8 h. The resultant coating was smoother and less hydrophobic than stainless steel. Changes in the coating's surface structure, thickness and chemistry indicate that the coating undergoes gradual erosion in aqueous medium, which results in release of subtilisin. Subtilisin activity in the coating increased initially, and then gradually decreased. After 9 months, 13% of the initial enzyme activity remained. Compared to stainless steel, the sol-gel-coated surfaces with active subtilisin were able to reduce bacterial attachment of both Gram positive and Gram negative bacteria by 2 orders of magnitude. Together, our results demonstrate that the sol-gel method is a promising coating technology for entrapping active enzymes, presenting an interesting avenue for enzyme-based antifouling solutions. PMID:23020255

  1. Ressources pour les personnes atteintes de démence

    PubMed Central

    Frank, Christopher; Feldman, Sid; Schulz, Mary

    2011-01-01

    Résumé Objectif Résumer les services offerts par la Société Alzheimer et discuter des autres sources de soutien et d’information à la disposition des personnes atteintes de démence. Sources de l’information On a fait une recension dans Ovid MEDLINE à l’aide des expressions dementia, Alzheimer disease, community health services utilization et caregiver stress. Message principal Il a été démontré qu’il est bénéfique aux patients et aux aidants si le diagnostic de la démence est posé tôt dans la maladie. Une consultation auprès de la Société Alzheimer peut aider dans la prise en charge non pharmacologique de la démence au moment du diagnostic et en tout temps durant l’évolution de la maladie. Parmi les services offerts, on peut mentionner des renseignements au sujet de la démence, le soutien aux aidants, la coordination des services communautaires et une grande diversité de ressources écrites à l’intention des patients et des aidants. Là où il est offert, le programme Premier lien peut aider avec l’orientation vers des services en minimisant la nécessité pour les patients ou les aidants de communiquer eux-mêmes avec les filiales locales de la Société. On discute aussi d’autres ressources, y compris les soins de répit et les approches technologiques pour prendre en charge l’errance. Conclusion La Société Alzheimer joue un rôle important dans la prise en charge de la démence et les médecins de famille devraient toujours envisager d’y référer leurs patients au moment du diagnostic, quelle que soit la gravité de l’état. Premier lien, quand il est accessible, peut faciliter le contact avec les services. Des ressources comme les soins de répit et les programmes de jour devraient toujours être considérés lorsqu’ils sont disponibles.

  2. Coupling Turbulence in Hybrid LES-RANS Techniques

    NASA Technical Reports Server (NTRS)

    Woodruff, Stephen L.

    2011-01-01

    A formulation is proposed for hybrid LES-RANS computations that permits accurate computations during resolution changes, so that resolution may be changed at will in order to employ only as much resolution in each subdomain as is required by the physics. The two components of this formulation, establishing the accuracy of a hybrid model at constant resolutions throughout the RANS-to-LES range and maintaining that accuracy when resolution is varied, are demonstrated for decaying, homogeneous, isotropic turbulence.

  3. Progress on LES of Flow Past a Circular Cylinder

    NASA Technical Reports Server (NTRS)

    Mittal, R.

    1996-01-01

    The objective of the present research is to assess the usefulness of large-eddy simulation (LES) methodology for flows in complex geometries. Flow past a circular cylinder has been calculated using a central-difference based solver, and the results have been compared to those obtained by a solver that employs higher-order upwind biased schemes (Beaudan & Moin, 1994). This comparison allows us to assess the suitability of these schemes for LES in complex geometry flows.

  4. Development of electrochromic smart windows by sol-gel techniques

    NASA Astrophysics Data System (ADS)

    Munro, Brian; Kraemer, S.; Zapp, P.; Krug, Herbert; Schmidt, Helmut K.

    1997-10-01

    A novel nanocomposite lithium ion-conducting electrolyte has been developed, based on organically modified silanes, which is suitable for application in a sol-gel electrochromic system. The system developed consists of FTO-coated (fluorine doped tin oxide) glass coated with tungsten oxide, WO3, at one side of the device as the electrochromic layer, with a cerium oxide-titanium oxide layer, CeO2-TiO2, acting as ion-storage layer or counter electrode. The adhesive properties of the electrolyte enabled the manufacture of electrochromic devices in a laminated structure: glassFTOWO3nanocomp.elect.CeO2-TiO2FTOglass. The conductivity of the nanocomposite electrolyte system varies between 10-4 and 10-5 Scm-1 at 25 degrees Celsius depending on the exact composition. The temperature dependence of the conductivity exhibits typical Vogel-Tamman-Fulcher (VTF) behavior. The thickness of the electrolyte between the two halves of the device could be adjusted by the use of a spacer technique in the range 10 - 150 micrometer. Optoelectrochemical measurements were conducted on electrochromic devices to study the kinetics of coloration and bleaching as a function of the number of switching cycles. At present, cells are constructed in two formats: 10 multiplied by 15 cm2 and 35 multiplied by 35 cm2. Switching times under one minute were achieved for the smaller format with a corresponding optical modulation between 75% to 20% (at lambda equals 0.633 micrometer). In the case of the larger format the switching time increases to several minutes due to the increase in geometric area.

  5. Characterization of Hafnia Powder Prepared from an Oxychloride Sol Gel

    SciTech Connect

    McGilvery, Catriona M.; De Gendt, S; Payzant, E Andrew; MacKenzie, M; Craven, A J; McComb, D W

    2011-01-01

    Hafnium containing compounds are of great importance to the semiconductor industry as a replacement for Si(O,N) with a high- gate dielectric. Whilst Hf is already being incorporated into working devices1, much is still to be understood about it. Here we investigate the crystallisation processes and chemistry of bulk HfO2 powders which will aid in interpretation of reactions and crystallisation events occurring in thin films used as gate dielectrics. Amorphous HfO2 powder was prepared via a sol-gel route using hafnium oxychloride (HfOCl2 xH2O) as a precursor. The powders were subjected to various heat treatments and analysed using x-ray diffraction (XRD) and thermal analysis techniques. It was found that a large change in the crystallisation pathway occurred when the sample was heated in an inert environment compared with in air. Instead of the expected monoclinic phase (m-HfO2), tetragonal HfO2 (t-HfO2) also formed under these conditions and was observed up to temperatures of ~760 C. The t-HfO2 particles, which are less than 30nm in size, eventually transform into m-HfO2 on further heating. Possible mechanisms for the crystallisation of t-HfO2 are discussed. It is proposed that within this temperature range t-HfO2 is stabilised due to the presence of oxygen vacancies in the inert environment, forming by the reduction of HfIV to HfIII. As the crystal grows in size as the temperature increases there are too few oxygen vacancies left in the structure to continue stabilising the t-HfO2 phase and so transformation to m-HfO2 occurs.

  6. Protection des ions organiques contre les dommages induits a l'ADN par les electrons de basse energie

    NASA Astrophysics Data System (ADS)

    Dumont, Ariane

    Il a ete demontre que les electrons de basse energie (EBE) peuvent induire des cassures simple brin (CSB) a l'ADN, via la formation d'anions transitoires qui decroissent par attachement dissociatif, ou dans d'autres etats electroniques dissociatifs menant a la fragmentation. Afin d'effectuer une etude complete des effets des electrons de basse energie sur la matiere biologique, il est necessaire de comprendre leur mecanismes d'interaction non seulement avec l'ADN, mais avec les constituants de son environnement. Les histones sont une composante importante de l'environnement moleculaire de l'ADN. Leur charge positive leur permet de s'associer aux groupements phosphate anionique de l'ADN. Le role principal de ces proteines basiques consiste a organiser l'ADN et l'empaqueter afin de former la chromatine. Les cations sont une autre composante importante de la cellule; ils jouent un role dans la stabilisation de la conformation B de l'ADN in vitro par leurs interactions avec les petits et grands sillons de l'ADN, ainsi qu'avec le groupement phosphate charge negativement. Avec les histones, ils participent egalement a la compaction de l'ADN pour former la chromatine. Cette etude a pour but de comprendre comment la presence d'ions organiques (sous forme de Tris et d'EDTA) a proximite de l'ADN modifie le rendement de cassures simple brin induit par les electrons de basse energie. Le Tris et l'EDTA ont-ete choisis comme objet d'etude, puisqu'en solution, ils forment le tampon standard pour solubiliser l'ADN dans les experiences in vitro (10mM Tris, 1mM EDTA). De plus, la molecule Tris possede un groupement amine alors que l'EDTA possede 4 groupements carboxyliques. Ensembles, ils peuvent se comporter comme un modele simple pour les acides amines. Le ratio molaire de 10 :1 de Tris par rapport a l'EDTA a pour but d'imiter le comportement des histones qui sont riches en arginine et lysine, acides amines possedant un groupement amine charge positivement additionnel. Des films d

  7. Impurity enrichment and radiative enhancement using induced SOL flow in DIII-D

    SciTech Connect

    Wade, M.R.; West, W.P.; Wood, R.D.

    1998-07-01

    Experiments on DIII-D have demonstrated the efficacy of using induced scrap-off-layer (SOL) flow to preferentially enrich impurities in the divertor plasma. This SOL floe is produced through simultaneous deuterium gas injection at the midplane and divertor exhaust. Using this SOL flow, an improvement in enrichment (defined as the ratio of impurity fraction in the divertor to that in the plasma core) has been observed for all impurities in trace-level experiments (i.e., impurity level is non-perturbative), with the degree of improvement increasing with impurity atomic number. In the case of argon, exhaust gas enrichment using modest SOL flow is as high as 17. Using this induced SOL flow technique and argon injection, radiative plasmas have been produced that combine high radiation losses (P{sub rad}/P{sub input} > 70%), low core fuel dilution (Z{sub eff} < 1.9), and good core confinement ({tau}{sub E} > 1.0 {tau}{sub E,ITER93H}).

  8. Sol gel derived hydroxyapatite coatings on titanium and its alloy Ti6Al4V

    NASA Astrophysics Data System (ADS)

    Stoch, A.; Jastrzebski, W.; Długoń, E.; Lejda, W.; Trybalska, B.; Stoch, G. J.; Adamczyk, A.

    2005-06-01

    Titanium has been used for many medical and dental applications; however, its joining to a living bone is not satisfactorily good or the implant integration with bone tissue takes several months.The aim of this work is to produce hydroxyapatite (HAP) coatings on titanium and its alloy for facilitating and shortening the processes towards osseointegration. HAP coatings were obtained by sol-gel method with sol solutions prepared from calcium nitrate tetrahydrate and triammonium phosphate trihydrate as the calcium and phosphorous sources. Two types of gelatine were added to the sol: agar-agar or animals gelatine. Both were found to enhance the formation and stability of amorphous HAP using soluble salts as the sources of calcium and phosphate. HAP coatings were deposited from HAP-GEL sol using dip-withdrawal technique, then the plates were dried and annealed at temperatures 460-750 °C. FTIR spectroscopy and XRD analysis were used to study the phase composition of phosphate coatings. Morphology and chemical analysis of HAP layers was performed using a scanning electron microscope equipped with an energy dispersive X-ray analyser (SEM+EDX). The biological activity of sol-gel phosphate coatings was observed during thermostatic held in simulated body fluid (SBF). It was found that chemical composition and structure of HAP coatings depends on pH and final thermal treatment of the layer.

  9. Screen-printable sol-gel enzyme-containing carbon inks.

    PubMed

    Wang, J; Pamidi, P V; Park, D S

    1996-08-01

    Enzymes usually cannot withstand the high-temperature curing associated with the thick-film fabrication process and require a separate immobilization step in connection with the production of single-use biosensors. We report on the development of sol-gel-derived enzyme-containing carbon inks that display compatibility with the screen-printing process. Such coupling of sol-gel and thick-film technologies offers a one-step fabrication of disposable enzyme electrodes, as it obviates the need for thermal curing. The enzyme-containing sol-gel carbon ink, prepared by dispersing the biocatalyst, along with the graphite powder and a binder, within the sol-gel precursors, is cured very rapidly (10 min) at low temperature (4 °C). The influence of the ink preparation conditions is explored, and the sensor performance is evaluated in connection with the incorporation of glucose oxidase or horseradish peroxidase. The resulting strips are stable for at least 3 months. Such sol-gel-derived carbon inks should serve as hosts for other heat-sensitive biomaterials in connection with the microfabrication of various thick-film biosensors. PMID:21619216

  10. Roughness evolution of sol-gel optical coatings by ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Gailly, P.; Dubreuil, O.; Fleury-Frenette, K.

    2015-12-01

    The surface roughness evolution of two silica-based sol-gel materials under 650 eV argon ion beam sputtering has been investigated. The liquid sol-gel solutions were applied on silicon substrates using the dip coating technique and thermally cured to obtain thin solid films and their thicknesses were then controlled over the samples surface using spectroscopic ellipsometry. The surface roughness of the sol-gel films was measured using both interferometric profilometry and atomic force microscopy depending on the obtained sputtering depths. We observed a significant increase of the roughness according to the sputtering depth, faster in the case of sol-gel layers than with bulk fused silica. Interestingly, the sputtering rates of the sol-gel layers were found much higher than the rate obtained on bulk fused silica. The development of micron scale holes with relatively stable interstices is supposed to rule the surface roughness evolution. AFM measurements revealed a regular submicron scale lateral structure which nanometric amplitude is amplified within sputtering.

  11. Sol-gel prepared glass for micro-optical elements and arrays

    NASA Astrophysics Data System (ADS)

    Haruvy, Yair; Gilath, Irith; Maniewictz, M.; Eisenberg, Naftali P.

    1997-09-01

    Sol-gel processes of metal alkoxides involve hydrolysis of the alkoxy groups and condensation to a 3-D oxide glass network. Volume reduction of the drying gel typically results in cracking, unless sufficient relaxation is allowed to take place. Further, the common shrinkage by a factor of 2.5 and higher imposes great difficulty to obtain dimensional accuracy in thus prepared micro-optical elements. The new fast sol-gel method enables facile preparation of siloxane-based glassy materials in which polymerization is completed within minutes and curing within a few hours. The optical quality of thin films obtained by the fast sol-gel method and the ease of preparation makes this method technologically and economically attractive for micro-lenses and micro-optical arrays by replication. Micro-optical arrays are highly patterned, including sharp curvatures of small radii. This necessitates to study primarily two aspects of the sol-gel replication process: (1) the chemical constitution of the sol-gel and the reaction pathway that ensures prompt adhesion to the template during the process. (2) the surface chemical adaptation of the template that allows timing of adhesion and release of the produced elements. The adaptation of this process to the desired replication is described. Thence, the results of preliminary fabrication of micro-optical elements and arrays by this method are shown and their features discussed.

  12. Beta zeolite supported sol-gel TiO2 materials for gas phase photocatalytic applications.

    PubMed

    Lafjah, Mama; Djafri, Fatiha; Bengueddach, Abdelkader; Keller, Nicolas; Keller, Valérie

    2011-02-28

    Beta zeolite supported sol-gel TiO(2) photocatalytic materials were prepared according to a sol-gel route in which high specific surface area Beta zeolite powder was incorporated into the titanium isopropoxide sol during the course of the sol-gel process. This led to an intimate contact between the zeolite surface and the TiO(2) precursors, and resulted in the anchorage of large amounts of dispersed TiO(2) nanoparticles and in the stabilization of TiO(2) in its anatase form, even for high TiO(2) wt. contents and high calcination temperatures. Taking the UV-A photocatalytic oxidation of methanol as gas phase target reaction, high methanol conversions were obtained on the Beta zeolite supported TiO(2) photocatalysts when compared to bulk sol-gel TiO(2), despite lower amounts of TiO(2) within the photoactive materials. The methanol conversion was optimum for about 40 wt.% TiO(2) loading and calcination temperatures of 500-600°C. PMID:21177024

  13. Optical characterization of anti reflective sol-gel coatings fabricated using dip coating method

    NASA Astrophysics Data System (ADS)

    Melninkaitis, A.; Juškevičius, K.; Maciulevičius, M.; Sirutkaitis, V.; Beganskienė, A.; Kazadojev, I.; Kareiva, A.; Perednis, D.

    2007-01-01

    In recent years, there has been a growing interest in further development of sol-gel method which can produce ceramics and glasses using chemical precursors at relative low-temperatures. The applications for sol-gel derived products are numerous. Department of General and Inorganic Chemistry with Laser Research Center of Vilnius University and Institute of Physics continues an ongoing research effort on the synthesis, deposition and characterization of porous solgel. Our target is highly optically resistant anti-reflective (AR) coatings for general optics and nonlinear optical crystals. In order to produce AR coatings a silica (SiO II) sol-gel has been dip coated on the set of fused silica substrates. The optical properties and structure of AR-coatings deposited from hydrolysed tetraethylorthosilicate (TEOS) sol were characterized in detail in this study. The influence of different parameters on the formation of colloidal silica antireflective coatings by dip-coating technique has been investigated. All samples were characterized performing, transmission electron microscopy, UV-visible spectroscopy, atomic force microscopy, ellipsometric, total scattering and laser-induced damage threshold measurements. Herewith we present our recent results on synthesis of sol-gel solvents, coating fabrication and characterization of their optical properties.

  14. From inulin to fructose syrups using sol-gel immobilized inulinase.

    PubMed

    Santa, Gonçalo L M; Bernardino, Susana M S A; Magalhães, Salomé; Mendes, Vanessa; Marques, Marco P C; Fonseca, Luís P; Fernandes, Pedro

    2011-09-01

    The present work aims to provide the basic characterization of sol-gel immobilized inulinase, a biocatalyst configuration yet unexploited, using as model system the hydrolysis of inulin to fructose. Porous xerogel particles with dimensions in slight excess of 10 μm were obtained, yielding an immobilization efficiency of roughly 80%. The temperature- and pH-activity profiles displayed a broader bell-shaped pattern as a result of immobilization. In the latter case, a shift of the optimal pH of 0.5 pH units was observed towards a less acidic environment. The kinetic parameters estimated from the typical Michaelis-Menten kinetics suggest that immobilization in sol-gel did not tamper with the native enzyme conformation, but on the other hand, entrapment brought along mass transfer limitations. The sol-gel biocatalyst displayed a promising operational stability, since it was used in more than 20 consecutive 24-hour batch runs without noticeable decay in product yield. The performance of sol-gel biocatalyst particles doped with magnetite roughly matched the performance of simple sol-gel particles in a single batch run. However, the operational stability of the former proved poorer, since activity decay was evident after four consecutive 24-hour batch runs. PMID:21445597

  15. Mechanical compatibility of sol-gel annealing with titanium for orthopaedic prostheses.

    PubMed

    Greer, Andrew I M; Lim, Teoh S; Brydone, Alistair S; Gadegaard, Nikolaj

    2016-01-01

    Sol-gel processing is an attractive method for large-scale surface coating due to its facile and inexpensive preparation, even with the inclusion of precision nanotopographies. These are desirable traits for metal orthopaedic prostheses where ceramic coatings are known to be osteoinductive and the effects may be amplified through nanotexturing. However there are a few concerns associated with the application of sol-gel technology to orthopaedics. Primarily, the annealing stage required to transform the sol-gel into a ceramic may compromise the physical integrity of the underlying metal. Secondly, loose particles on medical implants can be carcinogenic and cause inflammation so the coating needs to be strongly bonded to the implant. These concerns are addressed in this paper. Titanium, the dominant material for orthopaedics at present, is examined before and after sol-gel processing for changes in hardness and flexural modulus. Wear resistance, bending and pull tests are also performed to evaluate the ceramic coating. The findings suggest that sol-gel coatings will be compatible with titanium implants for an optimum temperature of 500 °C. PMID:26691162

  16. Spectroscopic and electrochemical characterization of cytochrome c encapsulated in a bio sol-gel matrix.

    PubMed

    Deriu, Daniela; Pagnotta, Sara Emanuela; Santucci, Roberto; Rosato, Nicola

    2008-08-01

    Sol-gel technique represents a remarkably versatile method for protein encapsulation. To enhance sol-gel biocompatibility, systems envisaging the presence of calcium and phosphates in the sol-gel composition were recently prepared and investigated. Unfortunately, the low pH at which solutions were prepared (pH < 2.5) dramatically limited their application to proteins, because the acidic environment induces protein denaturation. In this paper we apply a new protocol based on the introduction of calcium nitrate to the inorganic phase, with formation of a binary bioactive system. In this case protein encapsulation results versatile and secure, being achieved at a pH close to neutrality (pH 6.0); also, the presence of calcium is expected to enhance system biocompatibility. To determine the properties of the salt-doped sol-gel and the influence exerted on entrapped biosystems, the structural and functional properties of embedded cytochrome c have been investigated. Data obtained indicate that the salt-doped sol-gel induces no significant change in the structure and the redox properties of the embedded protein; also, the matrix increases protein stability. Interestingly, the presence of calcium nitrate appears determinant for refolding of the acid-denatured protein. This is of interest in the perspective of future applications in biosensoristic area. PMID:18163198

  17. Ventilatory impairment in the dysmyelinated Long Evans shaker (les) rat

    PubMed Central

    Johnson, Rebecca A.; Baker-Herman, Tracy L.; Duncan, Ian D.; Mitchell, Gordon S.

    2010-01-01

    Although respiratory complications significantly contribute to morbidity/mortality in advanced myelin disorders, little is known concerning mechanisms whereby dysmyelination impairs ventilation, or how patients compensate (i.e. plasticity). To establish a model for studies concerning mechanisms of ventilatory impairment/compensation, we tested the hypotheses that respiratory function progressively declines in a model of CNS dysmyelination, the Long Evans shaker rat (les). The observed impairment is associated with abnormal inspiratory neural output. Minimal myelin staining was found throughout the CNS of les rats, including the brainstem and cervical bulbospinal tracts. Ventilation (via whole-body plethysmography) and phrenic motor output were assessed in les and wild-type (WT) rats during baseline, hypoxia (11% O2) and hypercapnia (7% CO2). Hypercapnic ventilatory responses were similar in young adult les and WT rats (2 months old); in hypoxia, rats exhibited seizure-like activity with sustained apneas. However, 5–6 month old les rats exhibited decreased breathing frequencies, mean inspiratory flow (VT/TI) and ventilation (V̇E) during baseline and hypercapnia. Although phrenic motor output exhibited normal burst frequency and amplitude in 5–6 month old les rats, intra-burst activity was abnormal. In WT rats, phrenic activity was progressive and augmenting; in les rats, phrenic activity was decrementing with asynchronized, multipeaked activity. Thus, although ventilatory capacity is maintained in young, dysmyelinated rats, ventilatory impairment develops with age, possibly through discoordination in respiratory motor output. This study is the first reporting age-related breathing abnormalities in a rodent dysmyelination model, and provides the foundation for mechanistic studies of respiratory insufficiency and therapeutic interventions. PMID:20542092

  18. Les Johnson Views Interstellar Sail Material

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Engineers at Marshall Space Flight Center's (MSFC) Interstellar Propulsion Research department are proposing different solutions to combustion propellants for future space travel. One alternative being tested is the solar sail. The idea is, once deployed, the sail will allow solar winds to propel a spacecraft away from Earth and towards its destination. This would allow a spacecraft to travel indefinitely without the need to refuel during its ong journey. Thin reflective sails could be propelled through space by sunlight, microwave beams, or laser beams, just as the wind pushes sailboats on Earth. The sail will be the largest spacecraft ever built, sparning 440 yards, twice the diameter of the Louisiana Super Dome. Construction materials are being tested in a simulated space environment, where they are exposed to harsh conditions to test their performance and durability in extremely hot and cold temperatures. A leading candidate for the construction material is a carbon fiber material whose density is less than 1/10 ounce per square yard, the equivalent of flattening one raisin to the point that it covers a square yard. In space, the material would unfurl like a fan when it is deployed from an expendable rocket. This photo shows Les Johnson, manager of MSFC's Interstellar Propulsion Research Center holding the rigid, lightweight carbon fiber. An artist's concept of the sail is on the right. Mankind's first venture outside of our solar system is proposed for launch in a 2010 timeframe. An interstellar probe, powered by the fastest spacecraft ever flown, will zoom toward the stars at 58 miles per second. It will cover the distance from New York to Los Angeles in less than a minute and will travel over 23 billion miles beyond the edge of the solar system.

  19. Hydroxyapatite coating on Ti6Al4V alloy by a sol-gel method.

    PubMed

    Wang, Diangang; Chen, Chuanzhong; He, Ting; Lei, Tingquan

    2008-06-01

    Using trimethyl phosphate and calcium nitrate tetrahydrate as the calcium and phosphorus precursors, respectively, HA films were prepared layer by layer by a sol-gel method. The phase constitution, microstructure and calcium/phosphorus (Ca/P) molar ratio of the sol-gel films were studied by X-ray diffraction (XRD) and electronic probe microanalysis (EPMA). The results show that the sol-gel films have high crystallinity and are composed of HA and CaO phases, and the Ca/P ratio is slightly higher than the theoretical value in HA because of the loss of phosphorous element. Two typical cauliflower-like and lamellar structures were observed in the films. Cauliflower-like structure, which increases the biological reactivity of the implant surface towards natural bone, formed mainly at low drying temperature and high calcining temperature, while the lamellar structure formed when the drying temperature is high (500 degrees C or above). PMID:18071873

  20. Tantalum-Tungsten Oxide Thermite Composite Prepared by Sol-Gel Synthesis and Spark Plasma Sintering

    SciTech Connect

    Cervantes, O; Kuntz, J; Gash, A; Munir, Z

    2009-02-13

    Energetic composite powders consisting of sol-gel derived nanostructured tungsten oxide were produced with various amounts of micrometer-scale tantalum fuel metal. Such energetic composite powders were ignition tested and results show that the powders are not sensitive to friction, spark and/or impact ignition. Initial consolidation experiments, using the High Pressure Spark Plasma Sintering (HPSPS) technique, on the sol-gel derived nanostructured tungsten oxide produced samples with higher relative density than can be achieved with commercially available tungsten oxide. The sol-gel derived nanostructured tungsten oxide with immobilized tantalum fuel metal (Ta - WO{sub 3}) energetic composite was consolidated to a density of 9.17 g.cm{sup -3} or 93% relative density. In addition those parts were consolidated without significant pre-reaction of the constituents, thus the sample retained its stored chemical energy.

  1. A sol-powder coating technique for fabrication of yttria stabilised zirconia

    SciTech Connect

    Wattanasiriwech, Darunee . E-mail: darunee@mfu.ac.th; Wattanasiriwech, Suthee; Stevens, Ron

    2006-08-10

    Yttria stabilised zirconia has been prepared using a simple sol-powder coating technique. The polymeric yttria sol, which was prepared using 1,3 propanediol as a network modifier, was homogeneously mixed with nanocrystalline zirconia powder and it showed a dual function: as a binder which promoted densification and a phase modifier which stabilised zirconia in the tetragonal and cubic phases. Thermal analysis and X-ray diffraction revealed that the polymeric yttria sol which decomposed at low temperature into yttrium oxide could change the m {sup {yields}} t phase transformation behaviour of the zirconia, possibly due to the small particle size and very high surface area of both yttria and zirconia particles allowing rapid alloying. The sintered samples exhibited three crystalline phases: monoclinic, tetragonal and cubic, in which cubic and tetragonal are the major phases. The weight fractions of the individual phases present in the selected specimens were determined using quantitative Rietveld analysis.

  2. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

    NASA Astrophysics Data System (ADS)

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-04-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

  3. A new type of a sol-gel-derived inorganic-organic nanocomposite

    SciTech Connect

    Kasemann, R.; Schmidt, H.K.; Wintrich, E.

    1994-12-31

    A new type of sol-gel-based transparent inorganic-organic nano composites has been developed by increasing the inorganic phase dimension to values just below the point, where scattering can be neglected. For this purpose, nanosized boehmite particles {le} < 50 nm are homogeneously incorporated in a sol based on tetraethoxysilane and an epoxysilane. The nanoscale boehmite particles act as catalysts for the polymerization of the epoxy silane to polyethylene oxide, as proved by {sup 13}C NMR, and are linked to the matrix by Si-O-Al bridges, as proven by {sup 27}Al-NMR spectroscopy. The synthesized sols can be applied by standard coating techniques on transparent polymers and are cured thermally. The mechanical properties (scratch resistance, hardness) have been substantially improved compared to systems with molecular dimensions of the inorganic phase. The effect is attributed to the special structure of flexibly suspended nano-scale boehmite particles in an inorganic-organic network by a tailored interface.

  4. Optical activation of Si nanowires using Er-doped, sol-gel derived silica

    SciTech Connect

    Suh, Kiseok; Shin, Jung H.; Park, Oun-Ho; Bae, Byeong-Soo; Lee, Jung-Chul; Choi, Heon-Jin

    2005-01-31

    Optical activation of Si nanowires (Si-NWs) using sol-gel derived Er-doped silica is investigated. Si-NWs of about 100 nm diameter were grown on Si substrates by the vapor-liquid-solid method using Au catalysts and H{sub 2} diluted SiCl{sub 4}. Afterwards, Er-doped silica sol-gel solution was spin-coated, and annealed at 950 deg. C in flowing N{sub 2}/O{sub 2} environment. Such Er-doped silica/Si-NWs nanocomposite is found to combine the advantages of crystalline Si and silica to simultaneously achieve both high carrier-mediated excitation efficiency and high Er{sup 3+} luminescence efficiency while at the same time providing high areal density of Er{sup 3+} and easy current injection, indicating the possibility of developing sol-gel activated Si-NWs as a material platform for Si-based photonics.

  5. High-energy-density sol-gel thin film based on neat 2-cyanoethyltrimethoxysilane.

    PubMed

    Kim, Yunsang; Kathaperumal, Mohanalingam; Smith, O'Neil L; Pan, Ming-Jen; Cai, Ye; Sandhage, Kenneth H; Perry, Joseph W

    2013-03-13

    Hybrid organic-inorganic sol-gel dielectric thin films from a neat 2-cyanoethyltrimethoxysilane (CNETMS) precursor have been fabricated and their permittivity, dielectric strength, and energy density characterized. CNETMS sol-gel films possess compact, polar cyanoethyl groups and exhibit a relative permittivity of 20 at 1 kHz and breakdown strengths ranging from 650 V/μm to 250 V/μm for film thicknesses of 1.3 to 3.5 μm. Capacitors based on CNETMS films exhibit extractable energy densities of 7 J/cm(3) at 300 V/μm, as determined by charge-discharge and polarization-electric field measurements, as well as an energy extraction efficiency of ~91%. The large extractable energy resulting from the linear dielectric polarization behavior suggests that CNETMS films are promising sol-gel materials for pulsed power applications. PMID:23427818

  6. Thin film porous membranes based on sol-gel chemistry for catalytic sensors

    SciTech Connect

    Hughes, R.C.; Patel, S.V.; Jenkins, M.W.; Boyle, T.J.; Gardner, T.J.; Brinker, C.J.

    1998-05-01

    Nanoporous sol-gel based films are finding a wide variety of uses including gas separations and supports for heterogeneous catalysts. The films can be formed by spin or dip coating, followed by relatively low temperature annealing. The authors used several types of these films as coatings on the Pd alloy thin film sensors they had previously fabricated and studied. The sol-gel films have little effect on the sensing response to H{sub 2} alone. However, in the presence of other gases, the nanoporous film modifies the sensor behavior in several beneficial ways. (1) They have shown that the sol-gel coated sensors were only slightly poisoned by high concentrations of H{sub 2}S while uncoated sensors showed moderate to severe poisoning effects. (2) For a given partial pressure of H{sub 2}, the signal from the sensor is modified by the presence of O{sub 2} and other oxidizing gases.

  7. Photochromic organic-inorganic composite materials prepared by sol-gel processing: Properties and potentials

    SciTech Connect

    Hou, L. |; Mennig, M.; Schmidt, H.

    1994-12-31

    The sol-gel method which features a low-temperature wet-chemical process opens vast possibilities to incorporating organic dyes into solid matrices for various optical applications. In this paper the authors present their experimental results on the sol-gel derived photochromic organic-inorganic composite (Ormocer) materials following an introductory description of the sol-gel process and a brief review on the state of the art of the photochromic solids prepared using this method. Their photochromic spirooxazine-Ormocer gels and coatings possess better photochromic response and color-change speed than the corresponding photochromic polymer coatings and similar photochemical stability to the latter. Further developments are proposed as to tackle the temperature dependence problem and further tap the potentialities of the photochromic dye-Ormocer material for practical applications.

  8. Ultrapure glass optical waveguide development in microgravity by the sol-gel process

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.; Holman, R. A.

    1981-01-01

    Multicomponent, homogeneous, noncrystalline oxide gels can be prepared by the sol-gel process and these gels are promising starting materials for melting glasses in the space environment. The sol-gel process referred to here is based on the polymerization reaction of alkoxysilane with other metal alkoxy compounds or suitable metal salts. Many of the alkoxysilanes or other metal alkoxides are liquids and thus can be purified by distillation. The use of gels offers several advantages such as high purity and lower melting times and temperatures. The sol-gel process is studied for utilization in the preparation of multicomponent ultrapure glass batches for subsequent containerless melting of the batches in space to prepare glass blanks for optical waveguides.

  9. Laser-assisted sol-gel growth and characteristics of ZnO thin films

    SciTech Connect

    Kim, Min Su; Kim, Soaram; Leem, Jae-Young

    2012-06-18

    ZnO thin films were grown on Si(100) substrates by a sol-gel method assisted by laser beam irradiation with a 325 nm He-Cd laser. In contrast to conventional sol-gel ZnO thin films, the surface morphology of the laser-assisted sol-gel thin films was much smoother, and the residual stress in the films was relaxed by laser irradiation. The luminescent properties of the films were also enhanced by laser irradiation, especially, by irradiation during the deposition and post-heat treatment stages. The incident laser beam is thought to play several roles, such as annihilating defects by accelerating crystallization during heat treatment, enhancing the surface migration of atoms and molecules, and relaxing the ZnO matrix structure during crystallization.

  10. Preliminary fabrication of small Li{sub 2}O spheres by sol-gel method

    SciTech Connect

    Tsuchiya, K.; Kawamura, H.; Oyamada, R.; Nishimura, K.; Yoshimuta, H.; Watarumi, K.

    1995-12-31

    Lithium oxide (Li{sub 2}O) is one of the best tritium breeding materials. And as the shape of Li{sub 2}O, a small sphere is proposed in Japanese design of fusion blanket. Recently, reprocessing technology development on irradiated ceramic tritium breeders is conducted from the view point of effective use of resources and decrease of radioactive waste. The sol-gel method is most advantageous for fabricating small Li{sub 2}O spheres from the reprocessing solution with lithium. And the fabrication cost will be decreased by this method. In the present work, preliminary fabrication tests of small Li{sub 2}O spheres is carried out by the sol-gel method, and there are bright prospects for fabrication of small Li{sub 2}O spheres by sol-gel method.

  11. The porosity of sol-gel silica thin films for optrode applications

    SciTech Connect

    Harris, T.M.; Knobbe, E.T.

    1995-12-01

    Porous silica thin films produced by sol-gel processing are being considered for use in optical sensor (optrode) applications. In this study, thin films were produced by dip-coating onto glass slides. The porosity was then measured indirectly, by determining the amount of methylene blue adsorption on each slide. Using this technique, it has been determined that the {open_quotes}two-step{close_quotes} sol-gel process provides a greater surface area than the acid-catalyzed process. With the two-step process, increasing the amount of solvent (ethanol) and decreasing the rate of slide withdrawal from the sol provided increased surface area when normalized to the mass of the deposit.

  12. Preparation of Composite Coating on AZ91D Magnesium Alloy by Silica Sol-Micro Oxidation

    NASA Astrophysics Data System (ADS)

    Shao, Zhongcai; Zhang, Feifei; Zhao, Ruiqiang; Shen, Xiaoyi

    2016-03-01

    Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol-gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO2 gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.

  13. Titania sol-gel coatings with silver on non-porous titanium and titanium alloys

    NASA Astrophysics Data System (ADS)

    Horkavcova, D.; Cerny, M.; Sanda, L.; Novak, P.; Jablonska, E.; Zlamalova-Cflova, Z.; Helebrant, A.

    2016-04-01

    The objective of the work was to prepare and characterize titania sol-gel coatings on non-porous titanium and newly developed titanium alloys. Basic titania sol contained two forms of silver. Titania sol without silver was used as a reference sample. Coatings were prepared by dip-coating technique during stirring and fired. Coatings after firing were characterized by scanning electron microscopy. All titania coatings were measured to determine their adhesive and bactericidal properties. Adhesion of the coatings to the substrate was measured by tape test. Gram-negative bacteria E. coli was used for the bactericidal test. Coated substrates were immersed into suspension of E. coli in physiological solution for 24 hours. The in vitro cytotoxicity test was performed after one day. The bactericidal effect without toxicity was confirmed for selected coatings.

  14. A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features.

    PubMed

    Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

    2016-12-01

    Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields. PMID:27107773

  15. Gusev Dust Devil Movie, Sol 456 (Plain and Isolated)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 456th martian day, or sol (April 15, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera. Each frame in this movie has the raw image on the top half and a processed version in the lower half that enhances contrast and removes stationary objects, producing an image that is uniformly gray except for features that change from frame to frame.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection should trigger dust devils.

    Scientists will use the images to study several things. Tracking the dust devils tells which way the wind blows at different times

  16. Gusev Dust Devil Movie, Sol 459 (Plain and Isolated)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 459th martian day, or sol (April 18, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera. Each frame in this movie has the raw image on the top half and a processed version in the lower half that enhances contrast and removes stationary objects, producing an image that is uniformly gray except for features that change from frame to frame.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection should trigger dust devils.

    Scientists will use the images to study several things. Tracking the dust devils tells which way the wind blows at different times

  17. Non-hydrolytic Sol-gel Synthesis of Tin Sulfides

    NASA Astrophysics Data System (ADS)

    Kaur, Rajvinder

    The non-hydrolytic sol-gel (NHSG) process is an effective low temperature route well known for preparing homogeneous metal oxides. Thermodynamically as well as kinetically favored products, which cannot be prepared with the traditional solid-state routes, can be produced using NHSG. This project is focused on the exploration of NHSG synthesis of binary tin sulfides. In the past few years, metal sulfides have been the subject of significant interest. Much effort has been devoted to understand these materials because of their potential applications in electronic, optical, and superconductor devices.4 Among these materials, tin sulfides are materials of technological importance, which are being explored as semiconductors, anode materials for Li ion batteries, photoconductors, photocatalysts and absorber layer materials in photovoltaic solar cell devices. All of these applications depend upon features like homogeneity, oxidation state, high surface area and purity of the materials. These properties can be difficult to achieve by employing traditional synthetic routes, which require high temperatures due to slow diffusion, limiting the products to thermodynamically stable phases and prohibiting control over properties like particle size and surface area. A variety of low temperature methods are being explored due to the increased demand for such advanced materials. This project is focused on exploring the NHSG approach to synthesize binary tin sulfides, with the main goal of establishing conditions for the targeted synthesis of different tin sulfide polymorphs with controlled particle size. Being non-oxide materials, tin sulfides can be air sensitive, which requires special attention in handling. All reactions were carried out in absence of oxygen. This project explores the reaction of tin halides with thioethers in a dry solvent medium, leading to the formation of tin sulfides. There are a number of synthetic parameters that can be varied for the NHSG approach. A

  18. Sol-gel-based molecularly imprinted xerogel for capillary microextraction.

    PubMed

    Bagheri, Habib; Piri-Moghadam, Hamed

    2012-09-01

    A novel molecularly imprinted xerogel (MIX) based on organically modified silica (ORMOSIL) was successfully prepared for on-line capillary microextraction (CME) coupled with high-performance liquid chromatography (HPLC). The sol-gel-based xerogel was prepared using only one precursor and exhibited extensive selectivity towards triazines along with significant thermal and chemical stability. Atrazine was selected as a model template molecule and 3-(trimethoxysilyl)propylmethacrylate (TMSPMA) as a precursor in which the propylmethacrylate moiety was responsible for van der Waals, dipole-dipole, and hydrogen-bond interactions with the template. This moiety plays a key role in creation of selective sites while methoxysilyl groups in TMSPMA acted as crosslinkers between the template and the propylmethacrylate moiety. Moreover, a non-imprinted xerogel (NIX) was also prepared in the absence of the template for evaluating the extraction efficiency of the prepared MIX. Then, the prepared imprinted and non-imprinted xerogels were used for extraction of three selected analytes of triazines class including atrazine, ametryn, and terbutryn, which have rather similar structures. The extraction efficiency of the prepared xerogel for atrazine, the template molecule, was found to be ten times greater than the efficiency achieved by the non-imprinted one. In the meantime, the extraction efficiency ratio of MIX to NIX for ametryn and terbutryn was also rather significant (eight times). Moreover, other compounds from different classes including dicamba, mecoprop, and estriol were also analyzed to evaluate the selectivity of the prepared MIX towards triazines. The ratio of enrichment factors (EF) of MIX to NIX for atrazine, ametryn, terbutryn, dicamba, mecoprop, and estriol were about 10, 8, 8, 2, 2, and 3, respectively. The linearity for the analytes was in the range of 5-700 μg L(-1). Limit of detection was in the range of 1-5 μg L(-1) and the RSD% values (n = 5) were all below 6

  19. Development and characterization of molecularly imprinted sol-gel materials for the selective detection of DDT.

    PubMed

    Graham, Amy L; Carlson, Catherine A; Edmiston, Paul L

    2002-01-15

    Molecularly imprinting sol-gel materials for DDT using both a noncovalent and a covalent approach was examined. A nonpolar porous sol-gel network was created through the use of the bridged polysilsesquioxane, bis-(trimethoxysilylethyl)benzene (BTEB), as the principal sol-gel component. Noncovalent molecular imprinting was deemed unsuccessful, presumably because of the lack of strong intermolecular interactions that can be established between the DDT and the sol-gel precursor. A covalent imprinting strategy was employed by generating a sacrificial spacer through the reaction of two 3-isocyanatopropyltriethoxysilanes with one of two different template molecules: 4,4'-ethylenedianiline (EDA) or 4,4'-ethylidenebisphenol (EBP). After formation of the sol-gel, the bonds linking the spacer template to the matrix were cleaved in a manner that generated a pocket of the appropriate size bordered by amine groups that could aid in the binding of DDT through weak hydrogen bonding interactions. Experiments indicated that DDT could be bound selectively by such an approch. To generate a sensor, an environmentally sensitive fluorescent probe, 7-nitrobenz-2-oxa-1,3-diazole, (NBD) located adjacent to the DDT binding site was used to transduce the binding of analyte. EDA-imprinted sol-gels, deposited as films on glass microscope slides, were shown to quantitatively detect DDT in water to a limit-of-detection of 50 ppt with a response time of <60 s. Repeat measurements could be made with the same sensing films after rinsing with acetone between each measurement. The EDA sensing material was selective for DDT and other structurally similar molecules. However, the sensing film design was limited by the relatively minor changes in fluorescence intensity upon binding DDT. This situation may be remedied by an alternative methodology that can facilitate attachment of the NBD fluorophore in an optimal position proximal to the binding pocket. PMID:11811423

  20. Preparation of alkaline earth phosphates with sol containing sodium alginate and sodium diphosphate.

    PubMed

    Sugiyama, Shigeru; Fujii, Minako; Fukuta, Kazuya; Seyama, Kazunori; Sotowa, Ken-Ichiro; Shigemoto, Naoya

    2006-03-01

    Magnesium hydrogen phosphate, calcium hydroxyapatite, and strontium hydroxyapatite were successfully prepared from sol consisting of sodium alginate and Na4P2O7 with Mg2+, Ca2+, and Sr2+ in the corresponding nitrates, respectively. It is revealed that the order of the addition of those substrates and the role of sodium alginate are important factors for the preparation of desired phosphate compounds. According to the previous paper on the preparation of calcium hydroxyapatite, sodium alginate was mixed with aqueous Na4P2O7, followed by the addition of the aqueous divalent cations, resulting in the poor formation of the target phosphates. However, as a revised sol-gel technique, sodium alginate was added to the mixture of Na4P2O7 and aqueous Mg2+ and Sr2+, resulting in a rather favorable formation of MgHPO4 and strontium hydroxyapatite, respectively, while the sol thus obtained was stable within a few days. However for aqueous Ca2+, calcium hydroxyapatite could not be obtained through the revised sol-gel technique. In the preparation of magnesium hydrogen phosphate, sodium alginate contributes mainly to the sol formation of the precursor. The ion exchange between Na+ in sodium alginate and aqueous Ca2+ was important for the preparation of calcium hydroxyapatite. In contrast, the reaction of sodium alginate with the mixture of Na4P2O7 and aqueous Sr2+ afforded strontium hydroxyapatite at the specific ratio of those three substrates. The structure of calcium and strontium phosphates prepared from the revised sol-gel process evidently depended on the amount of sodium alginate introduced into the mixture of Na4P2O7 and the corresponding divalent cations. PMID:16154579

  1. Effect of calcium source on structure and properties of sol-gel derived bioactive glasses.

    PubMed

    Yu, Bobo; Turdean-Ionescu, Claudia A; Martin, Richard A; Newport, Robert J; Hanna, John V; Smith, Mark E; Jones, Julian R

    2012-12-18

    The aim was to determine the most effective calcium precursor for synthesis of sol-gel hybrids and for improving homogeneity of sol-gel bioactive glasses. Sol-gel derived bioactive calcium silicate glasses are one of the most promising materials for bone regeneration. Inorganic/organic hybrid materials, which are synthesized by incorporating a polymer into the sol-gel process, have also recently been produced to improve toughness. Calcium nitrate is conventionally used as the calcium source, but it has several disadvantages. Calcium nitrate causes inhomogeneity by forming calcium-rich regions, and it requires high temperature treatment (>400 °C) for calcium to be incorporated into the silicate network. Nitrates are also toxic and need to be burnt off. Calcium nitrate therefore cannot be used in the synthesis of hybrids as the highest temperature used in the process is typically 40-60 °C. Therefore, a different precursor is needed that can incorporate calcium into the silica network and enhance the homogeneity of the glasses at low (room) temperature. In this work, calcium methoxyethoxide (CME) was used to synthesize sol-gel bioactive glasses with a range of final processing temperatures from 60 to 800 °C. Comparison is made between the use of CME and calcium chloride and calcium nitrate. Using advanced probe techniques, the temperature at which Ca is incorporated into the network was identified for 70S30C (70 mol % SiO(2), 30 mol % CaO) for each of the calcium precursors. When CaCl(2) was used, the Ca did not seem to enter the network at any of the temperatures used. In contrast, Ca from CME entered the silica network at room temperature, as confirmed by X-ray diffraction, (29)Si magic angle spinning nuclear magnetic resonance spectroscopy, and dissolution studies. CME should be used in preference to calcium salts for hybrid synthesis and may improve homogeneity of sol-gel glasses. PMID:23171477

  2. ELM PARTICLE AND ENERGY TRANSPORT IN THE SOL AND DIVERTOR OF DIII-D

    SciTech Connect

    FENSTERMACHER,ME; LEONARD,AW; SNYDER,PB; BOEDO,JA; COLCHIN,RJ; GROEBNER,RJ; GRAY,DS; GROTH,M; HOLLMANN,E; LASNIER,CJ; OSBORNE,TH; PETRIE,TW; RUDAKOV,DL; TAKAHASHI,H; WATKINS,JG; ZENG,L

    2003-04-01

    A271 ELM PARTICLE AND ENERGY TRANSPORT IN THE SOL AND DIVERTOR OF DIII-D. Results from a series of dedicated experiments measuring the effect of particle and energy pulses from Type-I Edge Localized Modes (ELMs) in the DIII-D scrape-off layer (SOL) and divertor are compared with a simple model of ELM propagation in the boundary plasma. The simple model asserts that the propagation of ELM particle and energy perturbations is dominated by ion parallel convection along SOL fields lines and the recovery from the ELM perturbation is determined by recycling physics. Time scales associated with the initial changes of boundary plasma parameters are expected to be on the order of the ion transit time from the outer midplane, where the ELM instability is initiated, to the divertor targets. To test the model, the ion convection velocity is changed in the experiment by varying the plasma density. At moderate to high density, n{sub e}/n{sub Gr} = 0.5-0.8, the delays in the response of the boundary plasma to the midplane ELM pulses, the density dependence of those delays and other observations are consistent with the model. However, at the lowest densities, n{sub e}/n{sub Gr} {approx} 0.35, small delays between the response sin the two divertors, and changes in the response of the pedestal thermal energy to ELM events, indicate that additional factors including electron conduction in the SOL, the pre-ELM condition of the divertor plasma, and the ratio of ELM instability duration to SOL transit time, may be playing a role. The results show that understanding the response of the SOL and divertor plasmas to ELMs, for various pre-ELM conditions, is just as important to predicting the effect of ELM pulses on the target surfaces of future devices as is predicting the characteristics of the ELM perturbation of the core plasma.

  3. Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

    SciTech Connect

    King, C.M.; Thompson, M.C.; Buchanan, B.R.; King, R.B.; Garber, A.R.

    1989-12-31

    NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub l2}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sub 17}0 NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}]{sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an ``intercalation`` cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2}[(UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}] {center_dot} 8H{sub 2}0. This compound is the precursor to sintered U0{sub 2} ceramic fuel.

  4. Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

    SciTech Connect

    King, C.M.; Thompson, M.C.; Buchanan, B.R. ); King, R.B. . Dept. of Chemistry); Garber, A.R. . Dept. of Chemistry)

    1989-01-01

    NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub l2}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sub 17}0 NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, ((UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}){sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2}((UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}) {center dot} 8H{sub 2}0. This compound is the precursor to sintered U0{sub 2} ceramic fuel.

  5. Sol-gel deposited electrochromic films for electrochromic smart window glass

    SciTech Connect

    Oezer, N.; Lampert, C.M.; Rubin, M.

    1996-08-01

    Electrochromic windows offer the ability to dynamically change the transmittance of a glazing. With the appropriate sensor and controls, this smart window can be used for energy regulation and glare control for a variety of glazing applications. The most promising are building and automotive applications. This work covers the use of sol-gel deposition processes to make active films for these windows. The sol-gel process offers a low-capital investment for the deposition of these active films. Sol-gel serves as an alternative to more expensive vacuum deposition processes. The sol-gel process utilizes solution coating followed by a hydrolysis and condensation. In this investigation the authors report on tungsten oxide and nickel oxide films made by the sol-gel process for electrochromic windows. The properties of the sol-gel films compare favorably to those of films made by other techniques. A typical laminated electrochromic window consists of two glass sheets coated with transparent conductors, which are coated with the active films. The two sheets are laminated together with an ionically conductive polymer. The range of visible transmission modulation of the tungsten oxide was 60% and for the nickel oxide was 20%. The authors used the device configuration of glass/SnO{sub 2}:F/W0{sub 3}/polymer/Li{sub Z}NiO{sub x}H{sub y}/SnO{sub 2}:F glass to test the films. The nickel oxide layer had a low level of lithiation and possibly contained a small amount of water. Lithiated oxymethylene-linked poly(ethylene oxide) was used as the laminating polymer. Commercially available SnO{sub 2}:F/glass (LOF-Tec glass) was used as the transparent conducting glass. The authors found reasonable device switching characteristics which could be used for devices.

  6. Brûlure chez l’épileptique: brûlure pas comme les autres

    PubMed Central

    Boukind, S.; Elatiqi, O.K.; Dlimi, M.; Elamrani, D.; Benchamkha, Y.; Ettalbi, S.

    2015-01-01

    Summary L’association brûlure et épilepsie est une constatation fréquente au Maroc. Ces brûlures, souvent itératives, touchent le plus souvent des femmes jeunes de milieu rural. L’accident survient habituellement au domicile, le plus souvent dans la cuisine à la suite d’une chute sur un moyen de cuisson posé au sol. Elles peuvent être inaugurales de la maladie mais surviennent plus souvent chez des patients connus mais au traitement mal suivi. Les conséquences de ces brûlures, toujours profondes, sont souvent dramatiques en termes de séquelles, chez des patients ayant déjà une insertion sociale rendue difficile par l’épilepsie. La prise en charge doit être multidisciplinaire et concerner à la fois la brûlures et l’épilepsie. Des mesures de prévention simples, visant à équilibrer l’épilepsie et éviter au patient de se trouver seul à proximité d’une source de chaleur, doivent être mises en place. PMID:27252613

  7. Influence de l'alteration physique sur les caracteristiques physico-chimiques de monolithes de sols contamines traites par stabilisation/solidification au ciment

    NASA Astrophysics Data System (ADS)

    Remillard, Jonathan

    The concern of contaminated sites is affecting millions of property owner worldwide. As they pose a risk to the environment, human health or impair the value of buildings, remediation of contaminated sites has become an everyday issue. Stabilization/solidification (S/S) of contaminated soils with cement is a remediation technology that was developed to confine contaminants that cannot be degraded biologically, chemically or thermally by other technologies. Soils treated with S/S form a monolith that can be valorized on site. However, this practice is fairly uncommon in Quebec and this reluctance is partly due to the risks of degradation of the monoliths and the lack of knowledge relative to the long-term behavior of altered monoliths. The objective of this project was to simulate these degradations on cement-based monoliths of contaminated soils treated with S/S technology by causing physical alterations using different cycles of freeze/thawing and drying/wetting, and then to study the impact of these alterations on the mass losses, compressive strength, hydraulic conductivity, pH and leachability of five trace metals (Cd, Cr, Cu, Pb and Zn) used as contaminants. Various processes of S/S have been studied, either cement contents of 15 and 20%, then the presence of 5% by weight of calcium carbonate. For each S/S process formulated, the freeze/thaw cycles were much more effective in physically altering the monoliths. These alterations were mainly reflected by lower compressive strength, even more with lower cement contents. For their part, the drying/wetting cycles rather created a chemical change that lowered the pH of the monoliths. These chemical changes also affected the interpretation of leaching test results, especially for copper and zinc, since it was difficult to attribute effects to either physical or chemical alterations. The results showed that only chromium leached more clearly in response to physical alterations. All other elements studied were little affected, even though some samples were highly altered. This demonstrates that in some cases, damages may have little impact on long-term performance of the monoliths in terms of contaminant immobilization. However, integrating the study of long-term behaviors of monoliths in a process of formulation for contaminated soil treatment with S/S can become paramount, as seen for chromium in this present study. Keywords: stabilization / solidification, deterioration, alteration, leachability, contaminants.

  8. Systeme prototype pour le suivi des changements de l'occupation du sol en milieu urbain fonde sur les images du satellite RADARSAT-1

    NASA Astrophysics Data System (ADS)

    Fiset, Robert

    Land use and land cover mapping is of great importance for urban environment management. However, these maps become very rapidly outdated and require constant updating. Even in this day and age, most of the updating process is performed manually with the aid of aerial photography. The essential stages of this process consist in detecting the changes, establishing their nature and performing the database updating accordingly. Automating this operating procedure, even partially, is of utmost importance. Radar imagery may be acquired over large territories even in the presence of clouds. It has been the subject of very few research for urban mapping and there exists no operational application that makes use of it for map updating in this type of environment. However, it is well known that the imaging radar in general is sensitive to raised structures such as buildings. The apparition of new buildings in vacant areas, where most land cover and land use changes occur in urban areas, is clearly an indication for change detection. In the framework of this thesis, RADARSAT-1 imagery acquired in fine mode (10 meter resolution) has been investigated for its use in an innovative image processing method: the map-guided analysis of remote sensing data. The outdated map serves as a guide to segment a more recent image in order to compute characteristic features allowing to detect and identify changes. Tests show that texture measurements obtained with a fast method derived from the grey level co-occurrence matrix constitute such characteristic features allowing new buildings detection. Using 11 pixels square windows, contrast and entropy measurements are computed on a fine mode RADARSAT-1 image. Choosing appropriate thresholds is sufficient to pinpoint new buildings in vacant areas. Validation of this detection method is carried out over 5 sites presenting diverse physiographic characteristics using a dataset of 14 fine mode RADARSAT-1 images acquired with various incident angles throughout 1999. In the best cases, an accuracy of over 90% can be reached, while in the worst case this accuracy is around 75%. The results show that image acquisition using large incidence angles (F4 or F5) during a dry period (summer or fall) is preferable. With regard to the identification of the new taxons, it cannot be achieved with the radar imagery. Thus, a prototype system is developed to perform change detection using a RADARSAT-1 image, which then constitutes the key for the search by an operator into territorial databases (aerial photographs, land register, valuation rolls, etc.) to identify the new taxons. This prototype system, applied in a real case test, shows its potential for an operational use to accelerate and facilitate land use and land cover map updating over large territories. Key words. cartography, land use/land cover, urban areas, automatic updating, map-guided analysis, RADARSAT-l, texture measurements, grey level co-occurrence matrix.

  9. 76 FR 41816 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Ocotillo Sol Solar...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... & Electric's (SDG&E) right-of-way (ROW) authorization request for the Ocotillo Sol Solar Energy Facility (Project), a 15-18 megawatt (MW) solar energy facility. By this notice, the BLM is announcing the beginning... Ocotillo Sol Solar Project, Imperial County, CA; Possible Land Use Plan Amendment; and Notice...

  10. 77 FR 28618 - Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar Project Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ... alternatives. The CDCA plan, while recognizing the potential compatibility of solar energy facilities on public... Bureau of Land Management Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar... San Diego Gas & Electric (SDG&E) Ocotillo Sol Solar Project in Imperial County, California, and...

  11. Electrochemical and In Vitro Behavior of Nanostructure Sol-Gel Coated 316L Stainless Steel Incorporated with Rosemary Extract

    NASA Astrophysics Data System (ADS)

    Motalebi, Abolfazl; Nasr-Esfahani, Mojtaba

    2013-06-01

    The corrosion resistance of AISI 316L stainless steel for biomedical applications, was significantly enhanced by means of hybrid organic-inorganic sol-gel thin films deposited by spin-coating. Thin films of less than 100 nm with different hybrid characters were obtained by incorporating rosemary extract as green corrosion inhibitor. The morphology, composition, and adhesion of hybrid sol-gel coatings have been examined by SEM, EDX, and pull-off test, respectively. Addition of high additive concentrations (0.1%) did not disorganize the sol-gel network. Direct pull-off test recorded a mean coating-substrate bonding strength larger than 21.2 MPa for the hybrid sol-gel coating. The effect of rosemary extract, with various added concentrations from 0.012 to 0.1%, on the anticorrosion properties of sol-gel films have been characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in simulated body fluid (SBF) solution and has been compared to the bare metal. Rosemary extract additions (0.05%) have significantly increased the corrosion protection of the sol-gel thin film to higher than 90%. The in vitro bioactivity of prepared films indicates that hydroxyapatite nuclei can form and grow on the surface of the doped sol-gel thin films. The present study shows that due to their excellent anticorrosion properties, bioactivity and bonding strength to substrate, doped sol-gel thin films are practical hybrid films in biomedical applications.

  12. THERMALLY STABLE NANOCRYSTALLINE TIO2 PHOTOCATALYSTS SYNTHESIZED VIA SOL-GEL METHODS MODIFIED WITH IONIC LIQUID AND SURFACTANT MOLECULES

    EPA Science Inventory

    Recently, sol-gel methods employing ionic liquids (ILs) have shown significant implications for the synthesis of well-defined nanostructured inorganic materials. Herein, we synthesized nanocrystalline TiO2 particles via an alkoxide sol-gel method employing a water-immi...

  13. Modification of far-SOL flow by substantial gas injection in the inboard poloidal field null configuration on QUEST

    NASA Astrophysics Data System (ADS)

    Onchi, T.; Zushi, H.; Oyama, Y.; Mishra, K.; Nagashima, Y.; Hanada, K.; Idei, H.; Hasegawa, M.; Kuzmin, A.; Nakamura, K.; Fujisawa, A.; Nagaoka, K.; Quest Team

    2015-11-01

    Spontaneous plasma flow is generated in the inboard poloidal field null (IPN) configuration on QUEST spherical tokamak. Previous research has found that there is a significant relationship between plasma current and far-SOL flow. Consequently, the SOL flow is influenced by global modification of IPN plasma. For further understanding of the far-SOL flow, a hybrid probe measuring plasma flow, electron density ne, and temperature Te, was installed in the far-SOL. Using the hybrid probe and divertor probe array, two-point observation on an open flux surface was performed to study the SOL-divertor relationship and the particle transport. Substantial gas injection (GI) from private region of the IPN configuration leads to high core density but Ip-drop by 50 %. ne and Te in the far-SOL and divertor region are modified appreciably due to the GI. Poloidal flow reversal occurs and toroidal velocity drops by about 50 % in the far-SOL. We investigate modifications of pressure gradient, electric field and particle transport, and study complex structure of the far-SOL flow. This work is supported by Grants-in-aid for Scientific Research (S24226020, 15K17800) and the Collaborative Research Program of Research Institute for Applied Mechanics.

  14. Is It Just Me, or Are There Other Parents and Teachers Out There Confused about SOL Reading Assessments?

    ERIC Educational Resources Information Center

    Bintz, William P.

    1998-01-01

    Describes an incident involving the author, his daughter, and sample items from a Standards of Learning (SOL) assessment. Elaborates on the author's increasing confusion with SOL assessments, especially in reading. Proposes that educators spend less time testing kids and more time "testing their theories" so that assessments better reflect recent…

  15. Sol-Gel Application for Consolidating Stone: An Example of Project-Based Learning in a Physical Chemistry Lab

    ERIC Educational Resources Information Center

    de los Santos, Desiree´ M.; Montes, Antonio; Sa´nchez-Coronilla, Antonio; Navas, Javier

    2014-01-01

    A Project Based Learning (PBL) methodology was used in the practical laboratories of the Advanced Physical Chemistry department. The project type proposed simulates "real research" focusing on sol-gel synthesis and the application of the obtained sol as a stone consolidant. Students were divided into small groups (2 to 3 students) to…

  16. Sol-gel silica films embedding NIR- emitting Yb-quinolinolate complexes

    SciTech Connect

    Figus, Cristiana Quochi, Francesco Piana, Giacomo; Saba, Michele; Mura, Andrea; Bongiovanni, Giovanni; Artizzu, Flavia; Mercuri, Maria Laura; Serpe, Angela; Deplano, Paola

    2014-10-21

    Sol-gel silica thin films embedding an ytterbium quinolinolato complex (YbClQ{sub 4}) have been obtained using different alkoxides. Homogeneous, crack- and defect-free thin films of optical quality have been successfully deposited on glass substrate by dip-coating. The silica thin films have been characterized by time-resolved photoluminescence. The luminescence properties of the YbClQ{sub 4} are preserved in silica films prepared through an optimized sol-gel approach. The excited state lifetime of the lanthanide is comparable to those observed in bulk and longer than the corresponding ones in solution.

  17. Fabrication of CO sensing film by sol-gel method for application to microsensor

    SciTech Connect

    Wan-Young Chung; Duk-Dong Lee; Tamaki, Jun; Miura, Norio; Yamazoe, Noboru

    1996-12-31

    The most commonly used methods for the preparation of sensing film of micro-gas sensors are physical methods such as r.f. sputtering, thermal evaporation, spary pyrolysis and CVD. Though it is somewhat difficult to be compatible with microelectronic processes, the chemical preparation method such as sol-gel method has many advantages over the physical ones like additive incorporation and surface control. In this experiment, the authors have prepared tin oxide thin film by sol-gel method combined with spin-coating. The compatibility of the film process to the microelectronic process and CO gas sensing characteristics of the fabricated film have been investigated.

  18. Silica sol assisted chromatographic NMR spectroscopy for resolution of trans- and cis-isomers.

    PubMed

    Yang, Ying; Wu, Rui; Huang, Shaohua; Bai, Zhengwu

    2016-04-01

    Chromatographic NMR spectroscopy can separate the mixtures of species with significantly different molecular size, but generally fails for isomeric species. Herein, we reported the resolution of trans- and cis-isomers and their structural analogue, which are different in molecular shapes, but similar in mass, were greatly enhanced in the presence of silica sol. The mixtures of maleic acid, fumaric acid and succinic acid, and the mixtures of trans- and cis-1,2-cyclohexanedicarboxylic acids, were distinguished by virtue of their different degrees of interaction with silica sol. Moreover, we found mixed solvents could improve the spectral resolution of DOSY spectra of mixtures. PMID:26942864

  19. Silica sol assisted chromatographic NMR spectroscopy for resolution of trans- and cis-isomers

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Wu, Rui; Huang, Shaohua; Bai, Zhengwu

    2016-04-01

    Chromatographic NMR spectroscopy can separate the mixtures of species with significantly different molecular size, but generally fails for isomeric species. Herein, we reported the resolution of trans- and cis-isomers and their structural analogue, which are different in molecular shapes, but similar in mass, were greatly enhanced in the presence of silica sol. The mixtures of maleic acid, fumaric acid and succinic acid, and the mixtures of trans- and cis-1,2-cyclohexanedicarboxylic acids, were distinguished by virtue of their different degrees of interaction with silica sol. Moreover, we found mixed solvents could improve the spectral resolution of DOSY spectra of mixtures.

  20. Porous Silica Sol-Gel Glasses Containing Reactive V2O5 Groups

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E.

    1995-01-01

    Porous silica sol-gel glasses into which reactive vanadium oxide functional groups incorporated exhibit number of unique characteristics. Because they bind molecules of some species both reversibly and selectively, useful as chemical sensors or indicators or as scrubbers to remove toxic or hazardous contaminants. Materials also oxidize methane gas photochemically: suggests they're useful as catalysts for conversion of methane to alcohol and for oxidation of hydrocarbons in general. By incorporating various amounts of other metals into silica sol-gel glasses, possible to synthesize new materials with broad range of new characteristics.

  1. Tunable Bragg stacks from sol-gel derived Ta2O5 and MEL zeolite films

    NASA Astrophysics Data System (ADS)

    Gospodinov, B.; Dikova, J.; Mintova, S.; Babeva, T.

    2012-12-01

    In this paper we investigated sol-gel derived Ta2O5 and nanosized MEL zeolite films obtained by spin coating of Tantalum sol and colloidal zeolite solution, respectively. Refractive index and thickness of the films were determined using non-linear curve fitting of measured reflectance spectra. The influence of the post deposition annealing on the optical properties and thickness of the films was studied. Besides tunable Bragg stacks were designed and prepared by layer-by-layer deposition of Ta2O5 and MEL suspensions with quarter-wave thicknesses. The influence of water, acetone and methanol on the optical behavior of Bragg stacks was discussed.

  2. Transparent poly(vinyl acetate)-silica gels by a sol-gel process

    NASA Astrophysics Data System (ADS)

    Wojcik, Anna B.; Klein, Lisa C.

    1993-12-01

    Rod shaped silica-poly(vinyl acetate) (PVAc) gels have been prepared by a sol gel process. In situ polymerization of tetraethoxysilane (TEOS) was accomplished in the presence of low molecular weight PVAc by dissolving various amounts of PVAc in a mixture of TEOS, ethanol, water and hydrochloric acid (HCl). Gelation of this mixture was carried out between room temperature and slightly above. Silica-PVAc rods recovered from cylindrical molds were homogeneous and transparent. Gels with weight percents of PVAc ranging from 2% to 50% were prepared. Silica-PVAc gels have higher flexure strengths, less brittle character and improved water durability in comparison with pure sol- gel silica.

  3. Investigation of sol-gel yttrium doped ZnO thin films: structural and optical properties

    NASA Astrophysics Data System (ADS)

    Ivanova, T.; Harizanova, A.; Koutzarova, T.; Vertruyen, B.

    2016-02-01

    Nanostructured metal oxide films are extensively studied due to their numerous applications such as optoelectronic devices, sensors. In this work, we report the Y-Zn-O nanostructured films prepared by sol-gel technology from sols with different concentration of yttrium precursor, followed by post-annealing treatment. The Y doped ZnO thin films have been deposited on Si and quartz substrates by spin coating method, then treated at temperatures ranging from 300-800oC. XRD analysis reveals modification of the film structure and phases in the doped ZnO films.

  4. Les inconvénients de perdre du poids

    PubMed Central

    Bosomworth, N. John

    2012-01-01

    Résumé Objectif Explorer les raisons pour lesquelles la perte de poids à long terme échoue la plupart du temps et évaluer les conséquences de diverses trajectoires pondérales, y compris la stabilité, la perte et le gain. Source des données Les études qui évaluent les paramètres pondéraux dans la population sont en majorité observationnelles. Des données probantes de niveau I ont été publiées pour évaluer l’influence des interventions relatives au poids sur la mortalité et la qualité de vie. Message principal Seulement un petit pourcentage des personnes qui désirent perdre du poids réussissent à le faire de manière durable. La mortalité est la plus faible chez les personnes se situant dans la catégorie de poids élevé-normal et surpoids. La trajectoire pondérale la plus sécuritaire est la stabilité du poids avec une optimisation de la condition physique et métabolique. Il est démontré que la mortalité est plus faible chez les personnes ayant des comorbidités reliées à l’obésité si elles perdent du poids. Il est aussi établi que la qualité de vie sur le plan de la santé est meilleure chez les personnes obèses qui perdent du poids. Par contre, la perte de poids chez une personne obèse autrement en santé est associée à une mortalité accrue. Conclusion La perte de poids est recommandable seulement chez les personnes qui ont des comorbidités reliées à l’obésité. Les personnes obèses en santé qui veulent perdre du poids devraient être informées qu’il peut y avoir des risques à le faire. Une stratégie qui se traduit par un indice de masse corporelle stable avec une condition physique et métabolique optimisée, peu importe le poids, est l’option d’intervention la plus sécuritaire en ce qui concerne le poids.

  5. Development of novel Sol-Gel Indicators (SGI's) for in-situ environmental measurements: Part 1, Program and a new pH Sol-Gel Indicator

    SciTech Connect

    Livingston, R.R.; Baylor, L.; Wicks, G.G.

    1992-11-03

    The feasibility of incorporating analytical indicators into a sol-gel glassy matrix and then coating substrates with this composite material has bee demonstrated. Substrates coated include paper, wood, glass, and the lens of an analytical probe. The first SRTC sol-gel indicator, comprising bromophenol blue dispersed in a silica matrix, was fabricated and successfully used to measure solution pH in the range of pH 3.0 to 7.5. material exhibited a quick response time, as measured by color changes both qualitatively and quantitatively, and the measuring device was reversible or reusable. Additional indicators with responses over other ranges as well as indicators sensitive to the presence of elements of interest, are also under development. The new SGI composites possess promising properties and an excellent potential for performing a variety important in-situ environmental measurements and area discussed in this report.

  6. Effectiveness of silica based Sol-gel microencapsulation Method for odorants and flavours leading to sustainable Environment

    NASA Astrophysics Data System (ADS)

    Ashraf, Muhammad Aqeel; Khan, Ayesha Masood; Sarfraz, Maliha; Ahmad, Mushtaq

    2015-08-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped actives, thereby broadening the practical utilization of chemically unstable essential oils. Reviewing progress in the fabrication of diverse odorant and flavoured sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits.

  7. Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment.

    PubMed

    Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

    2015-01-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits. PMID:26322304

  8. Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment

    PubMed Central

    Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

    2015-01-01

    Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits. PMID:26322304

  9. Preparation of uniform TiO 2 nanostructure film on 316L stainless steel by sol-gel dip coating

    NASA Astrophysics Data System (ADS)

    Barati, N.; Sani, M. A. Faghihi; Ghasemi, H.; Sadeghian, Z.; Mirhoseini, S. M. M.

    2009-07-01

    Sol was prepared by the mixing of tetra-η-butyle titanat, ethyl aceto acetate, and ethanol in an optimized condition. Polished 316L specimens were coated with the sol by dip-coating method. The influences of drying condition, withdrawal speed, calcination temperature, addition of dispersant, and pH of sol on TiO 2 nanostructure coating were investigated. Choosing of alcohol as drying atmosphere hindered the crack formation. The relation between coating thickness and withdrawal speed was evaluated. The optimum temperature to create a uniform distribution of nanoparticles of anatase was derived as 400 °C. Average roughness of coating was found about 10.61 nm by AFM analysis. Dispersant addition promoted formation of a uniform film as well as prevention of agglomeration. Acidic sol provided smaller particles than neutral sol.

  10. Selectivity differences between sol-gel coated and immobilized liquid film open-tubular columns for gas chromatography.

    PubMed

    Kiridena, Waruna; Poole, Colin F; Koziol, Wiadyslaw W

    2002-12-01

    The solvation parameter model is used to determine the system constants for two sol-gel coated open-tubular columns at five equally spaced temperatures in the range 60-140 degrees C. Differences in the system constants as a function of temperature are used to determine the affect of sol-gel structure on the selectivity of SolGel-l and SolGel-Wax columns compared with conventionally coated and immobilized poly(dimethylsiloxane) and poly(ethylene glycol) stationary phases. The sol-gel columns should be suitable for similar separations to those presently performed on conventional immobilized liquid film columns of the same type but selectivity differences for polar compounds, which depend on temperature, should be anticipated. PMID:12537368

  11. Environmentally benign sol-gel antifouling and foul-releasing coatings.

    PubMed

    Detty, Michael R; Ciriminna, Rosaria; Bright, Frank V; Pagliaro, Mario

    2014-02-18

    Biofouling on ships and boats, characterized by aquatic bacteria and small organisms attaching to the hull, is an important global issue, since over 80000 tons of antifouling paint is used annually. This biofilm, which can form in as little as 48 hours depending on water temperature, increases drag on watercraft, which greatly reduces their fuel efficiency. In addition, biofouling can lead to microbially induced corrosion (MIC) due to H2S formed by the bacteria, especially sulfate-reducing bacteria. When the International Maritime Organization (IMO) international convention banned the use of effective but environmentally damaging coatings containing tributyl tin in 2008, the development of clean and effective antifouling systems became more important than ever. New nonbiocidal coatings are now in high demand. Scientists have developed new polymers, materials, and biocides, including new elastomeric coatings that they have obtained by improving the original silicone (polydimethylsiloxane) formulation patented in 1975. However, the high cost of silicones, especially of fluoropolymer-modified silicones, has generally prevented their large-scale diffusion. In 2009, traditional antifouling coatings using cuprous oxide formulated in copolymer paints still represented 95% of the global market volume of anti-fouling paints. The sol-gel nanochemistry approach to functional materials has emerged as an attractive candidate for creating low fouling surfaces due to the unique structure and properties of silica-based coatings and of hybrid inorganic-organic silicas in particular. Sol-gel formulations easily bind to all types of surfaces, such as steel, fiberglass, aluminum, and wood. In addition, they can cure at room temperature and form thin glassy coatings that are markedly different from thick silicone elastomeric foul-releasing coatings. Good to excellent performance against biofouling, low cure temperatures, enhanced and prolonged chemical and physical stability, ease of

  12. Les effets des interfaces sur les proprietes magnetiques et de transport des multicouches nickel/iron et cobalt/silver

    NASA Astrophysics Data System (ADS)

    Veres, Teodor

    Cette these est consacree a l'etude de l'evolution structurale des proprietes magnetiques et de transport des multicouches Ni/Fe et nanostructures a base de Co et de l'Ag. Dans une premiere partie, essentiellement bibliographique, nous introduisons quelques concepts de base relies aux proprietes magnetiques et de transport des multicouches metalliques. Ensuite, nous presentons une breve description des methodes d'analyse des resultats. La deuxieme partie est consacree a l'etude des proprietes magnetiques et de transport des multicouches ferromagnetiques/ferromagnetiques Ni/Fe. Nous montrerons qu'une interpretation coherente de ces proprietes necessite la prise en consideration des effets des interfaces. Nous nous attacherons a mettre en evidence, a evaluer et a etudier les effets de ces interfaces ainsi que leur evolution, et ce, suite a des traitements thermiques tel que le depot a temperature elevee et l'irradiation ionique. Les analyses correlees de la structure et de la magnetoresistance nous permettront d'emettre des conclusions sur l'influence des couches tampons entre l'interface et le substrat ainsi qu'entre les couches elles-memes sur le comportement magnetique des couches F/F. La troisieme partie est consacree aux systemes a Magneto-Resistance Geante (MRG) a base de Co et Ag. Nous allons etudier l'evolution de la microstructure suite a l'irradiation avec des ions Si+ ayant une energie de 1 MeV, ainsi que les effets de ces changements sur le comportement magnetique. Cette partie debutera par l'analyse des proprietes d'une multicouche hybride, intermediaire entre les multicouches et les materiaux granulaires. Nous analyserons a l'aide des mesures de diffraction, de relaxation superparamagnetique et de magnetoresistance, les evolutions structurales produites par l'irradiation ionique. Nous etablirons des modeles qui nous aideront a interpreter les resultats pour une serie des multicouches qui couvrent un large eventail de differents comportements magnetiques

  13. 20 CFR 10.709 - What happens if a beneficiary directed by OWCP or SOL to take action against a third party does...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OWCP or SOL to take action against a third party does not believe that a claim can be successfully... beneficiary directed by OWCP or SOL to take action against a third party does not believe that a claim can be... should request that OWCP or SOL release him or her from the obligation to proceed. This request should...

  14. 20 CFR 10.706 - How will a beneficiary know if OWCP or SOL has determined that action against a third party is...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How will a beneficiary know if OWCP or SOL... Third Party Liability § 10.706 How will a beneficiary know if OWCP or SOL has determined that action... is transferred to SOL, a second notification may be issued....

  15. A filtered tabulated chemistry model for LES of premixed combustion

    SciTech Connect

    Fiorina, B.; Auzillon, P.; Darabiha, N.; Gicquel, O.; Veynante, D.; Vicquelin, R.

    2010-03-15

    A new modeling strategy called F-TACLES (Filtered Tabulated Chemistry for Large Eddy Simulation) is developed to introduce tabulated chemistry methods in Large Eddy Simulation (LES) of turbulent premixed combustion. The objective is to recover the correct laminar flame propagation speed of the filtered flame front when subgrid scale turbulence vanishes as LES should tend toward Direct Numerical Simulation (DNS). The filtered flame structure is mapped using 1-D filtered laminar premixed flames. Closure of the filtered progress variable and the energy balance equations are carefully addressed in a fully compressible formulation. The methodology is first applied to 1-D filtered laminar flames, showing the ability of the model to recover the laminar flame speed and the correct chemical structure when the flame wrinkling is completely resolved. The model is then extended to turbulent combustion regimes by including subgrid scale wrinkling effects in the flame front propagation. Finally, preliminary tests of LES in a 3-D turbulent premixed flame are performed. (author)

  16. Eulerian Time-Domain Filtering for Spatial LES

    NASA Technical Reports Server (NTRS)

    Pruett, C. David

    1997-01-01

    Eulerian time-domain filtering seems to be appropriate for LES (large eddy simulation) of flows whose large coherent structures convect approximately at a common characteristic velocity; e.g., mixing layers, jets, and wakes. For these flows, we develop an approach to LES based on an explicit second-order digital Butterworth filter, which is applied in,the time domain in an Eulerian context. The approach is validated through a priori and a posteriori analyses of the simulated flow of a heated, subsonic, axisymmetric jet.

  17. Status of the SUSY Les Houches Accord II Project

    SciTech Connect

    Allanach, B.C.; Balazs, C.; Belanger, G.; Boudjema, F.; Choudhury, D.; Desch, K.; Ellwanger, U.; Gambino, P.; Godbole, R.; Guasch, J.; Guchait, M.; Heinemeyer, S.; Hugonie, C.; Hurth, T.; Kraml, S.; Lykken, J.; Mangano, M.; Moortgat, F.; Moretti, S.; Penaranda, S.; Porod, W.; /Fermilab

    2005-05-01

    Supersymmetric (SUSY) spectrum generators, decay packages, Monte-Carlo programs, dark matter evaluators, and SUSY fitting programs often need to communicate in the process of an analysis. The SUSY Les Houches Accord provides a common interface that conveys spectral and decay information between the various packages. Here, we propose extensions of the conventions of the first SUSY Les Houches Accord to include various generalizations: violation of CP, R-parity and flavor as well as the simplest next-to-minimal supersymmetric standard model (NMSSM).

  18. Les Hemorragies Gastroduodenales de Stress Chez le Brule Grave

    PubMed Central

    Siah, S.; Fouadi, F.E.; Ababou, K.; Nassim Sabah, T.; Ihrai, I.

    2008-01-01

    Summary Les Auteurs rapportent trois observations d'hémorragies gastroduodénales de stress chez le brûlé grave. Ils rappellent l'importance des mesures thérapeutiques qui doivent être prises chez le brûlé grave, comme le traitement du choc, du sepsis, des plaies et de la douleur, la nutrition entérale précoce et l'oxygénothérapie. Tout cela permet de réduire les facteurs de risque de survenue d'une hémorragie gastroduodénale de stress. PMID:21991137

  19. On integrating LES and laboratory turbulent flow experiments

    SciTech Connect

    Grinstein, Fernando Franklin

    2008-01-01

    Critical issues involved in large eddy simulation (LES) experiments relate to the treatment of unresolved subgrid scale flow features and required initial and boundary condition supergrid scale modelling. The inherently intrusive nature of both LES and laboratory experiments is noted in this context. Flow characterization issues becomes very challenging ones in validation and computational laboratory studies, where potential sources of discrepancies between predictions and measurements need to be clearly evaluated and controlled. A special focus of the discussion is devoted to turbulent initial condition issues.

  20. Sol-gel-derived silica films with tailored microstructures for applications requiring organic dyes

    SciTech Connect

    Logan, M.N.; Prabakar, S.; Brinker, C.J. |

    1994-09-01

    A three-step sol-gel process was developed to prepare organic dye-doped thin films with tailored porosity for applications in chemical sensing and optoelectronics. Varying the acid- and base-catalyzed hydrolysis steps of sols prepared from tetraethoxysilane with identical final H{sub 2}O/Si ratios, dilution factors and pH resulted in considerably different distributions of the silicate polymers in the sol (determined by {sup 29}Si NMR) and considerably different structures for the polymer clusters (determined by SAXS). During film formation these kinetic effects cause differences in the packing and collapse of the silicate network, leading to thin films with different refractive indices and volume fraction porosities. Under conditions where small pore-plugging species were avoided, the porosities of as-deposited films could be varied by aging the sol prior to film deposition. This strategy, which relies on the growth and aggregation of fractal polymeric clusters, is compatible with the low temperature and near neutral pH requirements of organic dyes.

  1. Ternary Phase-Separation Investigation of Sol-Gel Derived Silica from Ethyl Silicate 40

    PubMed Central

    Wang, Shengnan; Wang, David K.; Smart, Simon; Diniz da Costa, João C.

    2015-01-01

    A ternary phase-separation investigation of the ethyl silicate 40 (ES40) sol-gel process was conducted using ethanol and water as the solvent and hydrolysing agent, respectively. This oligomeric silica precursor underwent various degrees of phase separation behaviour in solution during the sol-gel reactions as a function of temperature and H2O/Si ratios. The solution composition within the immiscible region of the ES40 phase-separated system shows that the hydrolysis and condensation reactions decreased with decreasing reaction temperature. A mesoporous structure was obtained at low temperature due to weak drying forces from slow solvent evaporation on one hand and formation of unreacted ES40 cages in the other, which reduced network shrinkage and produced larger pores. This was attributed to the concentration of the reactive sites around the phase-separated interface, which enhanced the condensation and crosslinking. Contrary to dense silica structures obtained from sol-gel reactions in the miscible region, higher microporosity was produced via a phase-separated sol-gel system by using high H2O/Si ratios. This tailoring process facilitated further condensation reactions and crosslinking of silica chains, which coupled with stiffening of the network, made it more resistant to compression and densification. PMID:26411484

  2. Preparation and characterization of yttrium oxide by a sol-gel process

    SciTech Connect

    Hours, T.; Bergez, P.; Charpin, J. ); Larbott, A.; Guizard, C.; Cot, L. )

    1992-02-01

    This paper reports that submicron yttrium oxide was prepared from hydroxide precursors through a precipitation method. A parametric study was conducted at every stage from the yttrium hydroxide sols and powders, and also calcined oxide powders, were characterized with various techniques: light scattering, X-ray diffraction, infrared spectroscopy, specific area and particle size measurements, thermal analysis, and scanning electron microscopy.

  3. Foldable and Cytocompatible Sol-gel TiO2 Photonics

    NASA Astrophysics Data System (ADS)

    Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B.; Geiger, Sarah J.; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

    2015-09-01

    Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices.

  4. Foldable and Cytocompatible Sol-gel TiO2 Photonics

    PubMed Central

    Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B.; Geiger, Sarah J.; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

    2015-01-01

    Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices. PMID:26344823

  5. The influence of surfactants on the roughness of titania sol-gel films

    SciTech Connect

    Medina-Valtierra, Jorge . E-mail: jormeval@yahoo.com; Frausto-Reyes, Claudio . E-mail: cfraus@cio.mx; Calixto, Sergio . E-mail: scalixto@cio.mx; Bosch, Pedro . E-mail: lacv@xanum.uam.mx

    2007-03-15

    Substrate dipping in a composite sol-gel solution was used to prepare both smooth and rough thin films of titanium dioxide (TiO{sub 2}) on commercial fiberglass. The deposition of a composite film was done in a beaker using a solution of titanium (IV) isopropoxide as the sol-gel precursor and cetyltrimethyl ammonium bromide as the surfactant. In order to establish a correlation between experimental conditions and the titanium oxide produced, as well as the film quality, the calcined samples were characterized using Raman spectroscopy, UV-vis spectrophotometry, scanning electron microscopy and atomic force microscopy. One of the most important results is that a 61-nm TiO{sub 2} film was obtained with a short immersion of fiberglass into the sol-gel without surfactant. In other cases, the deposited film consisted of a titanium precursor gel encapsulating micelles of surfactant. The gel films were converted to only the anatase phase by calcining them at 500 deg. C. The resulting films were crystalline and exhibited a uniform surface topography. In the present paper, it was found that the TiO{sub 2} films prepared from the sol-gel with a surfactant showed a granular microstructure, and are composed of irregular particles between 1.5 and 3 {mu}m. Smooth TiO{sub 2} films could have useful optical and corrosion-protective properties and, on other hand, roughness on the TiO{sub 2} films can enhance the inherent photocatalytic activity.

  6. Sol immobilization technique: a delicate balance between activity, selectivity and stability for gold catalyst

    SciTech Connect

    Villa, Alberto; Wang, Di; Veith, Gabriel M; Prati, Laura

    2013-01-01

    Sol immobilization is a widely used method to prepare gold catalysts. The presence of the protective layer can have a significant influence on catalyst properties by mediating metal-support and reactantmetal interactions. This paper details the effect of a polyvinyl alcohol (PVA) protecting groups on the activity of a supported gold catalysts as well as its selectivity towards glycerol oxidation.

  7. Optical characterization of sol-gel derived Nb2O5 thin films

    NASA Astrophysics Data System (ADS)

    Lazarova, K.; Vasileva, M.; Marinov, G.; Babeva, T.

    2014-06-01

    The optical properties of thin Nb2O5 films, obtained by spin coating of Nb sol on glass and silicon substrates are investigated. The Nb sol was prepared by a sonocatalytic method using niobium chloride dissolved in ethanol. A calculation procedure for reliable and unambiguous determination of optical constants (refractive index and extinction coefficient) and thickness of films is developed that uses transmittance and reflectance measurements and non-linear curve fitting. By means of the developed procedure, the impacts of the sol ageing and the post deposition annealing on the optical properties and thickness of the films are investigated. It is demonstrated that films with controlled thicknesses and refractive index values in the range from 1.82 to 2.20 (at wavelength of 600 nm) could be obtained using different concentrations of the Nb sol and post deposition annealing in the range 60-650 °C. The possibility of fabrication of single layer anti-reflective coating for silicon is discussed.

  8. Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone

    NASA Astrophysics Data System (ADS)

    Evstrop'ev, S. K.; Gatchin, Yu. A.; Evstrop'ev, K. S.; Dukel'skii, K. V.; Kislyakov, I. M.

    2015-12-01

    Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of colloidal solutions in the UV spectral range are determined by the quantum-confinement effect, exhibiting a dependence of the absorption edge on the size of zinc sulfide nanocrystals.

  9. Two substrate-confined sol-gel coassembled ordered macroporous silica structures with an open surface.

    PubMed

    Guo, Wenhua; Wang, Ming; Xia, Wei; Dai, Lihua

    2013-05-21

    A sol-gel cooperative assembly method was demonstrated for the fabrication of inverse opal films with an open surface. In this method, a sol-gel silicate precursor was cooperatively assembled into the interstitial spaces of microspheres at the same time when polystyrene templates formed in between two desired substrates. Silica inverse opals with a three-dimensional ordered macroporous (3DOM) structure were obtained after selective removing the colloidal templates by calcination. The open surfaces with a high degree of interconnected porosity and extremely uniform pore size were characterized by scanning electron microscope (SEM). Optical transmission spectra reveals the existence of considerable deep band gaps of up to 70% and steep band edges of up to 6%/nm in the [111] directions of the 3DOM silica samples. A little shrinkage confirmed by transmission spectra is not larger than 3%, in consistent with the results measured by SEM, which revealing the sufficient and compact infiltration into the interstitial spaces by our confined sol-gel coassembly method. With different incidence angles, the positions of pseudogaps can be easily tuned in the wide range from 720 nm to 887 nm, agreed well with the calculated values by the Bragg law. All the results prove that the sol-gel coassembly method with two substrates confinement is a simple, low cost, convenient and versatile method for the fabrication of silica inverse opals without overlayers in large domains. PMID:23614663

  10. Low-density nanoporous iron foams synthesized by sol-gel autocombustion

    PubMed Central

    2012-01-01

    Nanoporous iron metal foams were synthesized by an improved sol-gel autocombustion method in this report. It has been confirmed to be pure phase iron by X-ray diffraction measurements. The nanoporous characteristics were illustrated through scanning electron microscope and transmission electron microscope images. Very low density and quite large saturation magnetization has been performed in the synthesized samples. PMID:22333555

  11. Electrophoretic deposition of TiO2/Er3+ nanoparticulate sols.

    PubMed

    Borlaf, Mario; Colomer, María Teresa; Cabello, Fátima; Serna, Rosalia; Moreno, Rodrigo

    2013-02-14

    TiO(2) and TiO(2)/Er(3+) nanoparticulate sols were obtained by the colloidal sol-gel route. Thanks to the combination of three optical techniques (laser diffraction, LD, dynamic light scattering, DLS, and multiple light scattering, MLS), the peptization time was quantified, demonstrating that erbium(III) ions retard the process. The isoelectric point of TiO(2) shifts up to higher pH's when Er(3+) ions are present, which suggests that they are adsorbed onto the surface of the TiO(2) nanoparticles. Moreover, the viscosity of the sols increases when the erbium(III) amount increases. The xerogels obtained from each sol were characterized by XRD and HRTEM, obtaining in all cases anatase as the major phase, although traces of brookite were also present. In the EPD experiments, the addition of ethanol was necessary to reduce the water hydrolysis and facilitate the drying process. As a result, transparent thin films were obtained at short times and low current densities and opal films for larger current densities and deposition times; in addition, the thickness, measured by ellipsometry, increased gradually, but the refractive index did not change significantly (1.9-2). The topography profile of the films and the particle size were obtained by atomic force microscopy (AFM), giving similar values to those measured by DLS, indicating that the addition of ethanol helps to maintain stabilization without further agglomeration or sedimentation. PMID:22799268

  12. VA State Profile. Virginia: Standards of Learning (SOL) End-of-Course Exams

    ERIC Educational Resources Information Center

    Center on Education Policy, 2010

    2010-01-01

    This paper provides information about Virginia's Standards of Learning (SOL) End-of-Course Exams. The purpose of the end-of-course assessments is to measure the achievement of students on the Standards of Learning adopted by the Virginia Board of Education for specific high school courses, and to ensure that students graduating from Virginia…

  13. Ternary Phase-Separation Investigation of Sol-Gel Derived Silica from Ethyl Silicate 40.

    PubMed

    Wang, Shengnan; Wang, David K; Smart, Simon; da Costa, João C Diniz

    2015-01-01

    A ternary phase-separation investigation of the ethyl silicate 40 (ES40) sol-gel process was conducted using ethanol and water as the solvent and hydrolysing agent, respectively. This oligomeric silica precursor underwent various degrees of phase separation behaviour in solution during the sol-gel reactions as a function of temperature and H2O/Si ratios. The solution composition within the immiscible region of the ES40 phase-separated system shows that the hydrolysis and condensation reactions decreased with decreasing reaction temperature. A mesoporous structure was obtained at low temperature due to weak drying forces from slow solvent evaporation on one hand and formation of unreacted ES40 cages in the other, which reduced network shrinkage and produced larger pores. This was attributed to the concentration of the reactive sites around the phase-separated interface, which enhanced the condensation and crosslinking. Contrary to dense silica structures obtained from sol-gel reactions in the miscible region, higher microporosity was produced via a phase-separated sol-gel system by using high H2O/Si ratios. This tailoring process facilitated further condensation reactions and crosslinking of silica chains, which coupled with stiffening of the network, made it more resistant to compression and densification. PMID:26411484

  14. Copper loaded on sol-gel-derived alumina adsorbents for phosphine removal.

    PubMed

    Hsu, Jung-Nan; Bai, Hsunling; Li, Shou-Nan; Tsai, Chuen-Jinn

    2010-05-01

    The hydride gas of phosphine (PH3) is commonly used for semiconductor and optoelectronic industries. The local scrubbers must immediately abate it because of its high toxicity. In this study, copper (Cu) loaded on the sol-gel-derived gamma-alumina (Al2O3) adsorbents are prepared and tested to investigate the possibility of PH3 removal and sorbent regeneration. Test results showed that during the breakthrough time of over 99% PH3 removal efficiency, the maximum adsorption capacity of Cu loaded on the sol-gel-derived gamma-Al2O3 adsorbent is 18 mg-PH3/g-adsorbent. This is much higher than that of Cu loaded on the commercial gamma-Al2O3 adsorbent--8.6 mg-PH3/g-adsorbent. The high specific surface area, narrow pore size distribution, and well dispersion of Cu loaded on the sol-gel-derived gamma-Al2O3 could be the reasons for its high PH3 adsorption capacity. The regeneration test shows that Cu loaded on the sol-gel-derived gamma-Al2O3 adsorbent can be regenerated after a simple air purging procedure. The cumulative adsorption capacity for five regeneration cycles is 65 mg-PH3/g-adsorbent, which is approximately double that of the Cu/zeolite adsorbent demonstrated in the literature. PMID:20480862

  15. Improving the temperature performance of low-density ceramic heatshields through sol-gel processing

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Leiser, Daniel; Sommers, Jeneen; Esfahani, Lili

    1991-01-01

    The performance of rigid insulations for use as thermal protection materials on reentry vehicles can be characterized by their resistance to dimensional and morphological change when exposed to an isothermal environment equivalent to that generated in entry. Improvements in these material characteristics for alumina-enhanced thermal barrier insulation by compositional modification through sol-gel processing are reported.

  16. Preparation and complex characterization of silica holmium sol-gel monoliths.

    PubMed

    Cacaina, D; Areva, S; Laaksonen, H; Simon, S; Ylänen, H

    2011-01-01

    Amorphous, sol-gel derived SiO(2) are known to biocompatible and bioresorbable materials. Biodegradable and inert materials containing radioactive isotopes have potential application as delivery vehicles of the beta radiation to the cancer tumors inside the body. Incorporation of holmium in the sol-gel derived SiO(2) could lead to the formation of a biodegradable material which could be used as carrier biomaterial for the radiation of radioactive holmium to the various cancer sites. The homogeneity of the prepared sol-gel silica holmium monoliths was investigated by Back Scattered Electron Imaging of Scanning Electron Microscope equipped with Energy Dispersive X-ray Analysis, X-ray Induced Photoelectron Spectroscopy and Nuclear Magnetic Resonance Spectroscopy. The biodegradation of the monoliths was investigated in Simulated Body Fluid and TRIS (Trizma pre-set Crystals) solution. The results show that by suitable tailoring of the sol-gel processing parameters holmium can be homogeneously incorporated in the silica matrix with a controlled biodegradation rate. PMID:21132520

  17. A micron-size sol-gel-derived fiber-optic based chemical sensor

    SciTech Connect

    Ingersoll, C.M.; Narang, U.; Bright, F.V.

    1995-12-31

    The development of new chemical and biosensing schemes has been a topic of great interest. In our laboratory, a portion of our work has centered on the use of sol-gels doped with fluorescent dyes as materials for forming small optical fibers used for sensing. We are currently working with pyrene-doped fibers for oxygen sensing and fluorescein-doped fibers to detect changes in pH. These schemes have shown great promise, however, several factors (e.g., cost, size, rigidity, response time, sensitivity) are associated with building practical sensors. It is also critical to understand the actual sol-gel composite gelation process in order to quantitatively determine the appropriate conditions for forming microsensor tips from these sol-gel materials. This presentation will focus on the construction of an inexpensive, micron-size fiber-optic sensor as well as a small flow-cell apparatus for the detection of various analytes. Also, the actual preparation of these sol-gel derived optical fibers will be discussed.

  18. Biological influence of Ca/P ratio on calcium phosphate coatings by sol-gel processing.

    PubMed

    Catauro, M; Papale, F; Sapio, L; Naviglio, S

    2016-08-01

    The objective of this work has been to develop low temperature sol-gel glass coatings to modify the substrate surface and to evaluate their bioactivity and biocompatibility. Glasses, based on SiO2·CaO·P2O5, were synthesized by the sol-gel technique using tetraethyl orthosilicate, calcium nitrate tetrahydrate and triethyl phosphate as precursors of SiO2, CaO and P2O5, respectively. Those materials, still in the sol phase, have been used to coat substrates by means of the dip-coating technique. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) has been used for characterize coatings and a microstructural analysis has been obtained using scanning electron microscopy (SEM). The potential applications of the coatings in the biomedical field were evaluated by bioactivity and biocompatibility tests. The coated substrate was immersed in simulated body fluid (SBF) for 21days and the hydroxyapatite deposition on its surface was subsequently evaluated via SEM-EDXS analysis, as an index of bone-bonding capability. In order to study the cell behavior and response to our silica based materials, prepared via the sol-gel method, with various Ca/P ratio and coating substrate, we have used the human osteoblast-like U2OS cell line. PMID:27157742

  19. The SOL Genomics Network. A Comparative Resource for Solanaceae Biology and Beyond1

    PubMed Central

    Mueller, Lukas A.; Solow, Teri H.; Taylor, Nicolas; Skwarecki, Beth; Buels, Robert; Binns, John; Lin, Chenwei; Wright, Mark H.; Ahrens, Robert; Wang, Ying; Herbst, Evan V.; Keyder, Emil R.; Menda, Naama; Zamir, Dani; Tanksley, Steven D.

    2005-01-01

    The SOL Genomics Network (SGN; http://sgn.cornell.edu) is a rapidly evolving comparative resource for the plants of the Solanaceae family, which includes important crop and model plants such as potato (Solanum tuberosum), eggplant (Solanum melongena), pepper (Capsicum annuum), and tomato (Solanum lycopersicum). The aim of SGN is to relate these species to one another using a comparative genomics approach and to tie them to the other dicots through the fully sequenced genome of Arabidopsis (Arabidopsis thaliana). SGN currently houses map and marker data for Solanaceae species, a large expressed sequence tag collection with computationally derived unigene sets, an extensive database of phenotypic information for a mutagenized tomato population, and associated tools such as real-time quantitative trait loci. Recently, the International Solanaceae Project (SOL) was formed as an umbrella organization for Solanaceae research in over 30 countries to address important questions in plant biology. The first cornerstone of the SOL project is the sequencing of the entire euchromatic portion of the tomato genome. SGN is collaborating with other bioinformatics centers in building the bioinformatics infrastructure for the tomato sequencing project and implementing the bioinformatics strategy of the larger SOL project. The overarching goal of SGN is to make information available in an intuitive comparative format, thereby facilitating a systems approach to investigations into the basis of adaptation and phenotypic diversity in the Solanaceae family, other species in the Asterid clade such as coffee (Coffea arabica), Rubiaciae, and beyond. PMID:16010005

  20. A Sol-Gel-Modified Poly(methyl methacrylate) Electrophoresis Microchip with a Hydrophilic Channel Wall

    SciTech Connect

    Chen, Gang; Xu, Xuejiao; Lin, Yuehe; Wang, Joseph

    2007-07-27

    A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was 27.4° compared with 66.3° for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13×10-4 cm2 V-1 s-1 for the native-PMMA channel to 4.86×10-4 cm2 V-1 s-1 for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74 882.3 m-1 compared with 14 730.5 m-1 for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.

  1. Optical properties of metallophthalocyanines in solution and in a sol-gel matrix

    NASA Astrophysics Data System (ADS)

    Acosta, Agnes; Sarkisov, Sergey S.; Wilkosz, Aaron; Leyderman, Alexander; Venkateswarlu, Putcha

    1997-10-01

    The sol-gel method is convenient for preparing amorphous transparent oxides with a wide range of optical properties including laser action, optical gain, phosphorescence, SHG and other non-linear effects. The sol-gel method was used to produce sol-gel samples using metallophthalocyanines. From metallophthalocyanines we used Cu (II) phthalocyanine (beta) - form, Ni (II) phthalocyaninetetrasulfonic acid, tetrasodium salt, Cu (II) 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis (dimethylamino)-29H, 31H-phthalocyanine, Zn 1,4,8,11,15,18,22,25-octabutoxy- 29H,31H-phthalocyanine Ni (II) 5,9,14,18,23,27,32,36-octabutoxy- 2,3-napthalocyanine and Cu (II) 5,9,14,18,23,27,32,36-octabutoxy-2,3-napthalocyanine. In our paper we report and discuss the results obtained from the measurements of the index of refraction using the prism coupling technique, absorption spectra and non-linear transmission measurements using picosecond laser pulses. The absorption spectras of Cu, Zn and Ni phthalocyanines in solution and sol-gel matrix showed decomposition. We found optical limiting after 0.2 J/cm2 in Ni (II) phthalocyaninetetrasulfonic acid, tetrasodium salt solution; glass samples showed no optical limiting. The mean of the index of refraction measured for all the (beta) -Cu phthalocyanine samples was 1.42. No birefringency was found.

  2. Thin-film silica sol-gel coatings for neural microelectrodes.

    PubMed

    Pierce, Andrew L; Sommakia, Salah; Rickus, Jenna L; Otto, Kevin J

    2009-05-30

    The reactive tissue response of the brain to chronically implanted materials remains a formidable obstacle to stable recording from implanted microelectrodes. One approach to mitigate this response is to apply a bioactive coating in the form of an ultra-porous silica sol-gel, which can be engineered to improve biocompatibility and to enable local drug delivery. The first step in establishing the feasibility of such a coating is to investigate the effects of the coating on electrode properties. In this paper, we describe a method to apply a thin-film silica sol-gel coating to silicon-based microelectrodes, and discuss the resultant changes in the electrode properties. Fluorescently labeled coatings were used to confirm coating adherence to the electrode. Cyclic voltammetry and impedance spectroscopy were used to evaluate electrical property changes. The silica sol-gel was found to successfully adhere to the electrodes as a thin coating. The voltammograms revealed a slight increase in charge carrying capacity of the electrodes following coating. Impedance spectrograms showed a mild increase in impedance at high frequencies but a more pronounced decrease in impedance at mid to low frequencies. These results demonstrate the feasibility of applying silica sol-gel coatings to silicon-based microelectrodes and are encouraging for the continued investigation of their use in mitigating the reactive tissue response. PMID:19427536

  3. Ternary Phase-Separation Investigation of Sol-Gel Derived Silica from Ethyl Silicate 40

    NASA Astrophysics Data System (ADS)

    Wang, Shengnan; Wang, David K.; Smart, Simon; Diniz da Costa, João C.

    2015-09-01

    A ternary phase-separation investigation of the ethyl silicate 40 (ES40) sol-gel process was conducted using ethanol and water as the solvent and hydrolysing agent, respectively. This oligomeric silica precursor underwent various degrees of phase separation behaviour in solution during the sol-gel reactions as a function of temperature and H2O/Si ratios. The solution composition within the immiscible region of the ES40 phase-separated system shows that the hydrolysis and condensation reactions decreased with decreasing reaction temperature. A mesoporous structure was obtained at low temperature due to weak drying forces from slow solvent evaporation on one hand and formation of unreacted ES40 cages in the other, which reduced network shrinkage and produced larger pores. This was attributed to the concentration of the reactive sites around the phase-separated interface, which enhanced the condensation and crosslinking. Contrary to dense silica structures obtained from sol-gel reactions in the miscible region, higher microporosity was produced via a phase-separated sol-gel system by using high H2O/Si ratios. This tailoring process facilitated further condensation reactions and crosslinking of silica chains, which coupled with stiffening of the network, made it more resistant to compression and densification.

  4. The SOLS TICE Project: Satellite Television and Audioconferencing in Continuing Professional Development for LIS Staff.

    ERIC Educational Resources Information Center

    Hughes, Alun; Priestley, John

    1992-01-01

    Describes SOLS TICE, the Satellite On-Line Searching Interactive Conferencing Experiment, conducted at the University of Plymouth (United Kingdom) to meet the training needs of staff in the library and information science (LIS) sector. Continuing professional development is discussed, instructional effectiveness and cost effectiveness are…

  5. Rethinking TESOL from a SOL's Perspective: Indigenous Epistemology and Decolonizing Praxis in TESOL

    ERIC Educational Resources Information Center

    Shin, Hyunjung

    2006-01-01

    In this paper, as a "SOL" of TESOL, I examine the conjunction between TESOL and colonialism, its manifestation in the South Korean context, and how to create a counter-hegemonic space to envision decolonizing TESOL praxis through explication and repudiation of such colonial discourse in TESOL. In particular, I focus on decolonizing knowledge…

  6. Missionaries and Tonic Sol-fa Music Pedagogy in 19th-Century China

    ERIC Educational Resources Information Center

    Southcott, Jane E.; Lee, Angela Hao-Chun

    2008-01-01

    In the 19th century, Christian missionaries in China, as elsewhere, used the Tonic Sol-fa method of music instruction to aid their evangelizing. This system was designed to improve congregational singing in churches, Sunday schools and missions. The London Missionary Society and other evangelical groups employed the method. These missionaries took…

  7. Sol-gel deposition of buffer layers on biaxially textured metal substances

    DOEpatents

    Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

    2000-01-01

    A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

  8. Sol-gel-derived silicate nano-hybrids for biomedical applications.

    PubMed

    Tsuru, Kanji; Shirosaki, Yuki; Hayakawa, Satoshi; Osaka, Akiyoshi

    2013-01-01

    Organic-inorganic hybrids of poly(dimethyl siloxane), gelatin, and chitosan with such silanes as tetraethoxysilane and 3-glycidoxytriethoxysilane are derived via the sol-gel routes. Their biomedical applications are discussed from biomimetic deposition of bone-like apatite, cell culture, and in vivo behavior. PMID:24189412

  9. OPTIMIZATION OF ALKYL ESTER PRODUCTION FROM GREASE USING A PHYLLOSILICATE SOL-GEL IMMOBILIZED LIPASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple alkyl ester derivatives of restaurant grease were prepared using a lipase from Pseudomonas cepacia immobilized within a phyllosilicate sol-gel matrix as biocatalyst. Alcoholysis reactions of grease were carried out in solvent-free media using a one step addition of alcohol to reaction mixtur...

  10. Detailed characteristics of drop-laden mixing layers: LES predictions compared to DNS

    NASA Technical Reports Server (NTRS)

    Okong'o, N.; Leboissetier, A.; Bellan, J.

    2004-01-01

    Results have been compared from Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) of a temporal mixing layer laden with evaporating drops, to assess the ability of LES to reproduce detailed characteristics of DNS.

  11. Définir les choix à risque: l'éthique et les effets des décisions organisationnelles.

    PubMed

    Warren, Marika

    2016-07-01

    Les choix de vivre « à risque » sont complexes et difficiles. Ils peuvent être structurés par les politiques organisationnelles. Certaines personnes veulent vraiment vivre dans des situations à haut risque ou perçues comme telles parce qu'elles en tirent un avantage important. Cependant, il est probable que ces choix dépendent en grande partie du contexte et qu'ils ne se soient pas posés dans une autre situation. L'article plaide pour la responsabilité d'être attentif aux effets des décisions organisationnelles sur les choix de vivre à risque et sur la répartition globale du risque. PMID:27365384

  12. Social values for ecosystem services (SolVES): Documentation and user manual, version 2.0

    USGS Publications Warehouse

    Sherrouse, Benson C.; Semmens, Darius J.

    2012-01-01

    In response to the need for incorporating quantified and spatially explicit measures of social values into ecosystem services assessments, the Rocky Mountain Geographic Science Center (RMGSC), in collaboration with Colorado State University, developed a geographic information system (GIS) application, Social Values for Ecosystem Services (SolVES). With version 2.0 (SolVES 2.0), RMGSC has improved and extended the functionality of SolVES, which was designed to assess, map, and quantify the perceived social values of ecosystem services. Social values such as aesthetics, biodiversity, and recreation can be evaluated for various stakeholder groups as distinguished by their attitudes and preferences regarding public uses, such as motorized recreation and logging. As with the previous version, SolVES 2.0 derives a quantitative, 10-point, social-values metric, the Value Index, from a combination of spatial and nonspatial responses to public attitude and preference surveys and calculates metrics characterizing the underlying environment, such as average distance to water and dominant landcover. Additionally, SolVES 2.0 integrates Maxent maximum entropy modeling software to generate more complete social value maps and to produce robust statistical models describing the relationship between the social values maps and explanatory environmental variables. The performance of these models can be evaluated for a primary study area, as well as for similar areas where primary survey data are not available but where social value mapping could potentially be completed using value-transfer methodology. SolVES 2.0 also introduces the flexibility for users to define their own social values and public uses, model any number and type of environmental variable, and modify the spatial resolution of analysis. With these enhancements, SolVES 2.0 provides an improved public domain tool for decisionmakers and researchers to evaluate the social values of ecosystem services and to facilitate

  13. Investigations of the small-scale thermal behavior of sol-gel thermites.

    SciTech Connect

    Warren, Mial E.; Farrow, Matthew; Tappan, Alexander Smith

    2009-02-01

    Sol-gel thermites, formulated from nanoporous oxides and dispersed fuel particles, may provide materials useful for small-scale, intense thermal sources, but understanding the factors affecting performance is critical prior to use. Work was conducted on understanding the synthesis conditions, thermal treatments, and additives that lead to different performance characteristics in iron oxide sol-gel thermites. Additionally, the safety properties of sol-gel thermites were investigated, especially those related to air sensitivity. Sol-gel thermites were synthesized using a variety of different techniques and there appear to be many viable routes to relatively equivalent thermites. These thermites were subjected to several different thermal treatments under argon in a differential scanning calorimeter, and it was shown that a 65 C hold for up to 200 minutes was effective for the removal of residual solvent, thus preventing boiling during the final thermal activation step. Vacuum-drying prior to this heating was shown to be even more effective at removing residual solvent. The addition of aluminum and molybdenum trioxide (MoO{sub 3}) reduced the total heat release per unit mass upon exposure to air, probably due to a decrease in the amount of reduced iron oxide species in the thermite. For the thermal activation step of heat treatment, three different temperatures were investigated. Thermal activation at 200 C resulted in increased ignition sensitivity over thermal activation at 232 C, and thermal activation at 300 C resulted in non-ignitable material. Non-sol-gel iron oxide did not exhibit any of the air-sensitivity observed in sol-gel iron oxide. In the DSC experiments, no bulk ignition of sol-gel thermites was observed upon exposure to air after thermal activation in argon; however ignition did occur when the material was heated in air after thermal treatment. In larger-scale experiments, up to a few hundred milligrams, no ignition was observed upon exposure to air

  14. PICARD SOL mission, a ground-based facility for long-term solar radius measurement

    NASA Astrophysics Data System (ADS)

    Meftah, M.; Irbah, A.; Corbard, T.; Morand, F.; Thuillier, G.; Hauchecorne, A.; Ikhlef, R.; Rouze, M.; Renaud, C.; Djafer, D.; Abbaki, S.; Assus, P.; Chauvineau, B.; Cissé, E. M.; Dalaudier, F.; D'Almeida, Eric; Fodil, M.; Laclare, F.; Lesueur, P.; Lin, M.; Marcovici, J. P.; Poiet, G.

    2012-09-01

    For the last thirty years, ground time series of the solar radius have shown different variations according to different instruments. The origin of these variations may be found in the observer, the instrument, the atmosphere and the Sun. These time series show inconsistencies and conflicting results, which likely originate from instrumental effects and/or atmospheric effects. A survey of the solar radius was initiated in 1975 by F. Laclare, at the Calern site of the Observatoire de la Cˆote d'Azur (OCA). PICARD is an investigation dedicated to the simultaneous measurements of the absolute total and spectral solar irradiance, the solar radius and solar shape, and to the Sun's interior probing by the helioseismology method. The PICARD mission aims to the study of the origin of the solar variability and to the study of the relations between the Sun and the Earth's climate by using modeling. These studies will be based on measurements carried out from orbit and from the ground. PICARD SOL is the ground segment of the PICARD mission to allow a comparison of the solar radius measured in space and on ground. PICARD SOL will enable to understand the influence of the atmosphere on the measured solar radius. The PICARD Sol instrumentation consists of: SODISM II, a replica of SODISM (SOlar Diameter Imager and Surface Mapper), a high resolution imaging telescope, and MISOLFA (Moniteur d'Images SOLaires Franco-Alǵerien), a seeing monitor. Additional instrumentation consists in a Sun photometer, which measures atmospheric aerosol properties, a pyranometer to measure the solar irradiance, a visible camera, and a weather station. PICARD SOL is operating since March 2011. First results from the PICARD SOL mission are briefly reported in this paper.

  15. Er3+-activated photonic structures fabricated by sol-gel and rf-sputtering techniques

    NASA Astrophysics Data System (ADS)

    Ferrari, M.; Alombert-Goget, G.; Armellini, C.; Berneschi, S.; Bhaktha, S. N. B.; Boulard, B.; Brenci, M.; Chiappini, A.; Chiasera, A.; Duverger-Arfuso, C.; Féron, P.; Gonçalves, R. R.; Jestin, Y.; Minati, L.; Moser, E.; Nunzi Conti, G.; Pelli, S.; Rao, D. N.; Retoux, R.; Righini, G. C.; Speranza, G.

    2009-05-01

    The realization of photonic structures operating at visible and near infrared frequencies is a highly attractive scientific and technological challenge. Since optical fiber innovation, a huge of activity has been performed leading to interesting results, such as optical waveguides and planar lightwave circuits, microphotonic devices, optical microcavities, nanowires, plasmonic structures, and photonic crystals. These systems have opened new possibilities in the field of both basic and applied physics, in a large area covering Information Communication Technologies, Health and Biology, Structural Engineering, and Environment Monitoring Systems. Several materials and techniques are employed to successfully fabricate photonic structures. Concerning materials, Er3+-activated silica-based glasses still play an important role, although recently interesting results have been published about fluoride glass-ceramic waveguides. As far as regards the fabrication methods sol-gel route and rf sputtering have proved to be versatile and reliable techniques. In this article we will present a review of some Er3+-activated photonic structures fabricated by sol gel route and rf sputtering deposition. In the discussion on the sol-gel approach we focus our attention on the silica-hafnia binary system presenting an overview concerning fabrication protocols and structural, optical and spectroscopic assessment of SiO2-HfO2 waveguides activated by Er3+ ions. In order to put in evidence the reliability and versatility of the sol-gel route for photonics applications four different confined structures are briefly presented: amorphous waveguides, coated microspheres, monolithic waveguide laser, and core-shell nanospheres. As examples of rf sputtering technique, we will discuss Er3+-activated silica-hafnia and silica-germania waveguides, the latter system allowing fabrication of integrated optics structures by UV photo-imprinting. Finally, two examples of photonic crystal structures, one

  16. Sol-gel processes and materials. November 1971-October 1989 (Citations from the US Patent data base). Report for November 1971-October 1989

    SciTech Connect

    Not Available

    1990-01-01

    This bibliography contains citations of selected patents concerning sol-gel processes and sol-gel derived materials and products. Selected patents include sol-gel compositions, ceramic and refractory materials, fabrication of silica glass, sol-gel thin films and coatings, transparent inorganic oxide glass, luminescent quartz glass, cataylsts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, sol-gel production of microspheres, alumina composites, photographic materials, and dental materials. (This updated bibliography contains 120 citations, 12 of which are new entries to the previous edition.)

  17. Sol-gel processes and materials. January 1970-August 1989 (Citations from the US Patent data base). Report for January 1970-August 1989

    SciTech Connect

    Not Available

    1989-09-01

    This bibliography contains citations of selected patents concerning Sol-Gel processes and Sol-Gel derived materials and products. Selected patents include Sol-Gel compositions, ceramic and refractory materials, fabrication of silica glass, Sol-Gel thin films and coatings, transparent inorganic oxide glass, luminescent quartz glass, cataylsts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, Sol-Gel production of microspheres, alumina composites, photographic materials, and dental materials. (This updated bibliography contains 108 citations, 37 of which are new entries to the previous edition.)

  18. CHARACTERIZATION OF THE 'PSEUDOMONAS AERUGINOSA' RECA GENE: THE LES (LYSOGENY ESTABLISHMENT DEFICIENT)- PHENOTYPE (JOURNAL VERSION)

    EPA Science Inventory

    The Les- (lysogeny establishment deficient) phenotype is a pleiotropic effect of the lesB908 mutation of Pseudomonas aruginosa PAO. LesB908-containing strains are also deficient in general recombination, sensitive to UV irradiation, and deficient in UV-stimulated induction of pro...

  19. Les reconstructions acétabulaires dans les prothèses totales de hanche

    PubMed Central

    Zejjari, Hassane; Louaste, Jamal; Cherrad, Taoufik; Bousbae, Hicham; Kasmaoui, Housseine; Amhajji, Larbi; Rachid, Khalid

    2015-01-01

    La chirurgie de reconstruction acétabulaire est une technique qui consiste à combler les pertes de substance osseuse siégeant au niveau du cotyle. Il s'agit d'une étude rétrospective de 15 patients (16 cotyles), sur une période de 6 ans (2006- 2012). Dans douze cas il s'agissait de prothèse totales de la hanche de première intention et dans quatre cas il s'agissait de reprise cotyloïdienne de PTH. L’évaluation clinique préopératoire et postopératoire de tous nos patients a été effectuée par le score de Postel et Merle d'Aubigné. L’évaluation des pertes de substances osseuse du cotyle a été classée selon la classification de Paprosky. L’âge moyen de nos patients au moment de l'intervention a été de 57 ans avec des extrêmes allant de 20 ans à 76 ans. La greffe osseuse a été utilisée chez 12 de nos patients. La reconstruction prothétique a été utilisée chez 8 patients (anneau de Kerboul dans six cas et anneau de Burch-Schneider dans deux cas). Recul post opératoire moyen a été de 56 mois. L’évaluation radiologique a été basée sur les clichés radiologiques du bassin de face strict ainsi que des radiographies de la hanche opérée de face prenant la totalité de la prothèse. Nos résultats cliniques et radiologiques ont été jugé bon à très bon dans la majorité des cas. Pour nous, nous optant pour le recentrage-reconstruction car c'est lui qui s'approche le plus de l'anatomie et de la biomécanique normale de la hanche. PMID:26955415

  20. [The Les Morts de la Rue collective, strong social commitment].

    PubMed

    Rocca, Cécile

    2016-02-01

    The problems faced by homeless people are varied and complex. They require numerous qualities on the part of professionals. Living on the streets often means dying on the streets. Professionals are thereby confronted with practical and ethical questions. They have a key role both in listening and providing support. This article shows the example of the Les Morts de la Rue collective. PMID:26861085

  1. DNS and LES of a Shear-Free Mixing Layer

    NASA Technical Reports Server (NTRS)

    Knaepen, B.; Debliquy, O.; Carati, D.

    2003-01-01

    The purpose of this work is twofold. First, given the computational resources available today, it is possible to reach, using DNS, higher Reynolds numbers than in Briggs et al.. In the present study, the microscale Reynolds numbers reached in the low- and high-energy homogeneous regions are, respectively, 32 and 69. The results reported earlier can thus be complemented and their robustness in the presence of increased turbulence studied. The second aim of this work is to perform a detailed and documented LES of the shear-free mixing layer. In that respect, the creation of a DNS database at higher Reynolds number is necessary in order to make meaningful LES assessments. From the point of view of LES, the shear-free mixing-layer is interesting since it allows one to test how traditional LES models perform in the presence of an inhomogeneity without having to deal with difficult numerical issues. Indeed, as argued in Briggs et al., it is possible to use a spectral code to study the shear-free mixing layer and one can thus focus on the accuracy of the modelling while avoiding contamination of the results by commutation errors etc. This paper is organized as follows. First we detail the initialization procedure used in the simulation. Since the flow is not statistically stationary, this initialization procedure has a fairly strong influence on the evolution. Although we will focus here on the shear-free mixing layer, the method proposed in the present work can easily be used for other flows with one inhomogeneous direction. The next section of the article is devoted to the description of the DNS. All the relevant parameters are listed and comparison with the Veeravalli & Warhaft experiment is performed. The section on the LES of the shear-free mixing layer follows. A detailed comparison between the filtered DNS data and the LES predictions is presented. It is shown that simple eddy viscosity models perform very well for the present test case, most probably because the

  2. Stochasticity of convection in Giga-LES data

    NASA Astrophysics Data System (ADS)

    De La Chevrotière, Michèle; Khouider, Boualem; Majda, Andrew J.

    2015-12-01

    The poor representation of tropical convection in general circulation models (GCMs) is believed to be responsible for much of the uncertainty in the predictions of weather and climate in the tropics. The stochastic multicloud model (SMCM) was recently developed by Khouider et al. (Commun Math Sci 8(1):187-216, 2010) to represent the missing variability in GCMs due to unresolved features of organized tropical convection. The SMCM is based on three cloud types (congestus, deep and stratiform), and transitions between these cloud types are formalized in terms of probability rules that are functions of the large-scale environment convective state and a set of seven arbitrary cloud timescale parameters. Here, a statistical inference method based on the Bayesian paradigm is applied to estimate these key cloud timescales from the Giga-LES dataset, a 24-h large-eddy simulation (LES) of deep tropical convection (Khairoutdinov et al. in J Adv Model Earth Syst 1(12), 2009) over a domain comparable to a GCM gridbox. A sequential learning strategy is used where the Giga-LES domain is partitioned into a few subdomains, and atmospheric time series obtained on each subdomain are used to train the Bayesian procedure incrementally. Convergence of the marginal posterior densities for all seven parameters is demonstrated for two different grid partitions, and sensitivity tests to other model parameters are also presented. A single column model simulation using the SMCM parameterization with the Giga-LES inferred parameters reproduces many important statistical features of the Giga-LES run, without any further tuning. In particular it exhibits intermittent dynamical behavior in both the stochastic cloud fractions and the large scale dynamics, with periods of dry phases followed by a coherent sequence of congestus, deep, and stratiform convection, varying on timescales of a few hours consistent with the Giga-LES time series. The chaotic variations of the cloud area fractions were

  3. Quantitative immunoelectrophoretic analysis of the plasma proteins in the sol phase of sputum from patients with chronic bronchitis

    PubMed Central

    Ryley, H. C.; Brogan, T. D.

    1973-01-01

    An analysis of the plasma proteins in the sol phase of sputum was carried out using quantitative cross immunoelectrophoresis. The average concentrations of nine plasma proteins were estimated in the sol phase of sputum specimens from 30 patients with chronic bronchitis and the values were compared with the concentrations of these proteins in saliva and serum specimens from the same group of patients. The results showed that alpha1 antichymotrypsin and IgA concentrations were higher in the sol phase of sputum than would be expected if their presence were due entirely to passive transudation. Images PMID:4128930

  4. Effect of PMMA impregnation on the fluorescence quantum yield of sol-gel glasses doped with quinine sulfate

    NASA Astrophysics Data System (ADS)

    Meneses-Nava, M. A.; Barbosa-García, O.; Díaz-Torres, L. A.; Chávez-Cerda, S.; Torres-Cisneros, M.; King, T. A.

    2001-08-01

    The fluorescence quantum yield of quinine sulfate in sol-gel and PMMA impregnated glasses is measured. The observed quantum yield improvement in the sol-gel matrix, compared to ethanol, is interpreted as a reduction of non-radiative relaxation channels by isolation of the molecules by the cage of the glass. PMMA impregnated sol-gel glasses show an extra improvement of the fluorescence yield, which is interpreted as a reduction of the free space and the rigid fixation of the molecules to the matrix.

  5. Effects of silica sol on the microstructure and mechanical properties of CaSiO3 bioceramics.

    PubMed

    Pan, Ying; Yin, Jinwei; Yao, Dongxu; Zuo, Kaihui; Xia, Yongfeng; Liang, Hanqin; Zeng, YuPing

    2016-07-01

    CaSiO3 ceramics were fabricated with silica sol addition by pressureless sintering. The effects of silica sol on phase composition, microstructure and mechanical properties of CaSiO3 ceramics were investigated. The silica sol additive was found to be effective in speeding up pore elimination, improving the grain growth, decreasing the sintering temperature and shortening the sintering time. When the amount of SiO2 was 5wt%, a flexural strength of 186.2MPa was achieved with an open porosity of 3.9%. The main crystal phase was β-CaSiO3 below sintering temperature of 1150°C. PMID:27127061

  6. Protéger les nourrissons contre la coqueluche

    PubMed Central

    Gilley, Meghan; Goldman, Ran D.

    2014-01-01

    Résumé Question Compte tenu du taux à la hausse de la coqueluche chez les enfants, plusieurs familles m’ont demandé quels moyens prendre pour protéger leurs tout-petits de cette infection. Quelles devraient être mes recommandations à ces familles? Réponse La coqueluche est une maladie évitable qui est endémique dans le monde entier. Chez les adultes, la coqueluche cause une maladie bénigne semblable à un rhume, suivie d’une toux persistante. Chez les nourrissons, elle peut causer de l’apnée, des convulsions, une encéphalopathie, une bronchopneumonie et la mort. Les décès dus à la coqueluche se produisent dans 86 % des cas chez des nourrissons de moins de 4 mois. La stratégie du cocooning, c’est-à-dire la vaccination des adultes en étroit contact avec des nourrissons, est recommandée par de nombreuses agences mondiales et nationales, mais elle ne prévient probablement que 20 % des cas de coqueluche chez les nourrissons. La vaccination durant la grossesse est plus efficace, mais elle n’est pas encore approuvée au Canada. Il n’a pas été démontré que la vaccination à la naissance soit uniformément efficace et elle n’est donc pas recommandée à l’heure actuelle.

  7. Les astronomes européens auscultent les cieux avec le plus grand télescope du monde

    NASA Astrophysics Data System (ADS)

    Malbet, F.

    2008-09-01

    À l'heure des projets de télescopes extrêmement grands, l'Europe a déjà une longueur d'avance. Le télescope européen (VLT), en mode interférométrique avec l'instrument AMBER devient le plus grand télescope jamais utilisé dans le domaine optique aussi bien en surface de miroir (plus de 150 m2) qúen finesse de résolution qui atteint celle d'un télescope de 130 m de diamètre. Le journal professionnel Astronomy & Astrophysics a publié en 2007 un numéro spécial qui rapporte les premiers résultats obtenus avec l'instrument AMBER (Astronomical MultiBEam Recombiner) par le très grand télescope européen. Ces articles couvrent pratiquement tous les stades de l'évolution stellaire depuis la formation des étoiles et des planètes jusqu'a l'observation de l'explosion de type nova dans un système stellaire évolué. Ces résultats inédits ont été obtenus en utilisant simultanément 3 des 4 télescopes du VLT basés à l'Observatoire européen austral du mont Paranal au Chili. L'instrument AMBER équipant le VLTI (mode interférométrique du VLT) permet dâatteindre une résolution angulaire inégalée de l'ordre du millième de seconde d'angle autorisant l'observation des astres dans différentes longueurs d'onde, dans l'infrarouge proche. Les astronomes obtiennent donc des observations avec une finesse 13 fois plus importante que celle d'un télescope seul. Il devient alors possible de sonder les régions de formation de planètes, d'observer les vents des étoiles en rotation très rapide, d'étudier les différents types de matières éjectées par une étoile massive, de séparer les deux composantes d'une étoile double serrée et de voir en direct l'évolution d'une nova quelques jours seulement après son explosion.

  8. Fiber-optic chemical sensors using sol-gel membranes and photocatalysts

    NASA Astrophysics Data System (ADS)

    Nivens, Delana Amber Gajdosik

    Fiber-optic sensors have been developed that incorporate multi-layer organo-silica sol-gel membranes. Multilayer sol-gel sensors have been designed to offer improved stability over other sol-gel membranes and to measure COsb2 and the unreactive analytes trichloroethylene and perchloroethylene. Single layer pH sensors were fabricated using a base-catalyzed organo-silica sol-gel containing organosilane coupling agents. A base catalyst was found to be better suited for complete incorporation of the aminopropyltriethoxysilane used to attach dye molecules. This allows the production of optically transparent gels that respond to pH in less than 15 seconds. Dual layer COsb2 sensors use the pH sol-gel layer overcoated with a hydrophobic ORganically MOdified SIlica sol-gel membrane (ORMOSIL). The ORMOSIL reduces much of the pH cross sensitivity found in gas sensors and allows fast, reversible diffusion of COsb2. The sensors respond to COsb2 gas within 10 seconds and dissolved COsb2 in 2 minutes. COsb2 sensors have been found to be stable and reproducible for 12 months when stored dry and at least 6 months when stored in buffer. Many volatile organochloride compounds (VOC's) have been difficult to measure using current fiber-optic sensor transduction schemes. The three-layer optical sensor described here incorporates a TiOsb2/SiOsb2 membrane to degrade VOC's into smaller, detectable products, Hsp+, Clsp- and COsb2. Upon exposure to UV light, TiOsb2, a semiconductor with a bandgap of 3.2 eV, produces highly reactive electron-hole pairs that photodegrade organic compounds. The products produced on the TiOsb2 surface diffuse into the nearby indicator membrane where they are detected. Carbon dioxide and protons produced are detected by the pH sensitive indicator layer described above. Preliminary data for the measurement of VOC's indicates that the detection limit for PCE is less than 1.65 ppm in the headspace (10 ppm in solution). Photocatalysis is also used to measure uranyl

  9. Synthesis and characterization of sol-gel-derived nanomaterials and nanocrystalline electroless metal coatings

    NASA Astrophysics Data System (ADS)

    Shukla, Satyajit Vishnu

    CuS (minimum size of 2.5 nm), Ag2S (minimum and average size of 2.5 nm and 26 nm respectively), and Au (with minimum size of <10 nm) nanoparticles dispersed within the sol-gel derived hydroxypropyl cellulose (HPC)-silica films are synthesized using the gas diffusion technique. The effectiveness of HPC polymer, as a 'compatibilizer', to synthesize semiconductor and metal nanoparticles distributed uniformly within the silica film is demonstrated. The sol-gel derived HPC-silica films containing dispersed nanoparticles are characterized using x-ray photoelectron spectroscopy (XPS) to understand the mechanism of formation of nanoparticles within the film. The XPS core-level binding energies (B.E.) for the nanoparticles are observed to be sensitive to the variation in the chemical composition at the surface and their size. The 'cluster size effect' is shown to be useful in predicting the average nanoparticle size. Nanocrystalline ZrO2 particles are successfully synthesized using sol-gel technique utilizing HPC polymer as a 'steric barrier'. The use of HPC polymer is demonstrated to synthesize submicron-sized, non-agglomerated, and spherical as well as nanocrystalline ZrO2 particles by adjusting the sol-gel synthesis parameters. The effect of sol-gel synthesis parameters on ZrO2 nanocrystallite size, its distribution, and the phase evolution behavior of ZrO2 is studied. The optimum sol-gel synthesis parameters for synthesizing nanocrystalline ZrO2 with 100% tetragonal phase are identified. Cu/CuO-ZrO2 composite powder is synthesized using the electroless metal deposition technique. The mechanism of electroless deposition of Cu over ZrO2 particle surface is investigated using XPS. On the basis of 'cluster size effect', it is suggested that, the electroless metal deposition process activates the non-catalytic ceramic substrate surface by depositing metallic Pd0 clusters and not by the accepted Pd-Sn alloy catalyst. Fly ash cenosphere particle surface is also activated by

  10. Les maladies chroniques non transmissibles chez les militaires sénégalais: étude transversale en 2013

    PubMed Central

    Aziz, Ndiaye Abdoul; Mohamed, Seck Sidy; Badara, Tall Alioune; Boubacar, Gueye; Gallo, Sow Papa; Awa, Gaye; Anta, Tal-Dia

    2015-01-01

    Introduction Les maladies chroniques non transmissibles (MCNT) constituent un problème de santé publique. La transition épidémiologique coexiste avec les maladies infectieuses. En Afrique subsaharienne, leur ampleur est peu connue et l'OMS recommande aux pays à faible et moyen revenu de réaliser des enquêtes STEPS portant sur les comportements, des mesures physiques et biochimiques. L'absence de données au niveau national justifie cette étude auprès d'un groupe spécifique. L'objectif de l’étude était de déterminer la prévalence des MCNT et de leurs facteurs de risque chez les militaires Sénégalais. Méthodes Une enquête transversale a été réalisée incluant les militaires âgés de 25 à 60 ans. La participation était volontaire et l'accord des autorités hiérarchiques a préalablement été obtenu. Un sondage stratifié à deux niveaux a été utilisé permettant d'avoir un échantillon ajusté de 1513 individus. Les données ont été saisies avec le logiciel EPI Info 6 et analysées à l'aide de R. Un score de risque a été déterminé sur la base de cinq facteurs. Résultats Les résultats préliminaires concernent 1125 personnes. L’âge moyen était de 39,7 ±9,1 ans et le sex-ratio de 28,6. La prévalence du tabagisme actif était de 17,3% et ne variait pas significativement entre les différentes catégories d’âge. L’âge moyen auquel ils ont commencé à fumer était de 20,8 ±4,05 ans. La consommation médiane de fruits et légumes était de l'ordre de 4 par jour et seulement 5,7% des enquêtés prenaient au moins 5 portions par jour. Environs 72% des enquêtés avaient une activité physique intense ou modérée. Les prévalences de la surcharge pondérale, de l'HTA et du diabète étaient de 30,5%, 28,4% et 3,0% respectivement alors que la maladie rénale chronique était retrouvée chez un seul cas. Le calcul du score de risque cardiovasculaire a montré que 39,1% des militaires étaient à risque élevé (≥3 facteurs

  11. Photoresist-Free Fully Self-Patterned Transparent Amorphous Oxide Thin-Film Transistors Obtained by Sol-Gel Process

    PubMed Central

    Lim, Hyun Soo; Rim, You Seung; Kim, Hyun Jae

    2014-01-01

    We demonstrated self-patterned solution-processed amorphous oxide semiconductor thin-film transistors (TFTs) using photosensitive sol-gels. The photosensitive sol-gels were synthesized by adding β-diketone compounds, i.e., benzoylacetone and acetylacetone, to sol-gels. The chemically modified photosensitive sol-gels showed a high optical absorption at specific wavelengths due to the formation of metal chelate bonds. Photoreactions of the modified solutions enabled a photoresist-free process. Moreover, Zn–Sn–O with a high Sn ratio, which is hard to wet-etch using conventional photolithography due to its chemical durability, was easily patterned via the self-patterning process. Finally, we fabricated a solution-processed oxide TFT that included fully self-patterned electrodes and an active layer. PMID:24686314

  12. Corrosion resistance of multilayer hybrid sol-gel coatings deposited on the AISI 316L austenitic stainless steel

    NASA Astrophysics Data System (ADS)

    Caballero, Y. T.; Rondón, E. A.; Rueda, L.; Hernández Barrios, C. A.; Coy, A.; Viejo, F.

    2016-02-01

    In the present work multilayer hybrid sol-gel coatings were synthesized on the AISI 316L austenitic stainless steel employed in the fabrication of orthopaedic implants. Hybrid sols were obtained from a mixture of inorganic precursor, TEOS, and organic, GPTMS, using ethanol as solvent, and acetic acid as catalyst. The characterization of the sols was performed using pH measurements, rheological tests and infrared spectroscopy (FTIR) for different ageing times. On the other hand, the coatings were characterized by scanning electron microscopy (SEM), while the corrosion resistance was evaluated using anodic potentiodynamic polarization in SBF solution at 37±2°C. The results confirmed that sol-gel synthesis employing TEOS-GPTMS systems produces uniform and homogeneous coatings, which enhanced the corrosion resistance with regard to the parent alloy. Moreover, corrosion performance was retained after applying more than one layer (multilayer coatings).

  13. Effect of chelating agent acetylacetone on corrosion protection properties of silane-zirconium sol-gel coatings

    NASA Astrophysics Data System (ADS)

    Yu, Mei; Liang, Min; Liu, Jianhua; Li, Songmei; Xue, Bing; Zhao, Hao

    2016-02-01

    The hybrid sol-gel coatings on AA2024-T3 were prepared with a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) and a metal alkoxide tetra-n-propoxyzirconium (TPOZ) as precursors. The effect of acetylacetone (AcAc) as a chelating agent on the corrosion protection properties of sol-gel coatings were evaluated and the optimal AcAc/TPOZ molar ratio was obtained. The sol-gel coatings were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The corrosion protection properties of the coatings were evaluated by means of potentiodynamic polarization study (PDS) and electrochemical impedance spectroscopy (EIS). It is demonstrated that AcAc avoids fast hydrolysis of TPOZ and benefits to form stable sols. The coating with AcAc/TPOZ molar ratio of 3 shows the best corrosion protection performance in 0.05 M NaCl solution.

  14. Measured and simulated poloidal asymmetries of the FTU S.O.L. in the toroidal limiter configuration

    NASA Astrophysics Data System (ADS)

    Leigheb, M.; Ridolfini, V. Pericoli; Zagorski, R.

    The scrape-off layer (SOL) of FTU in the magnetic configuration generated by a TZM (Molybdenum) toroidal limiter has been studied by an array of reciprocating Langmuir probes extended over a large part of the poloidal angle, and the results have been compared with the 2-dimensional multifluid SOL code EPIT. A comparison with the previous poloidal limiter configuration with the same main plasma conditions, showed at the last closed magnetic surface (LCMS) longer and more poloidally uniform connection lengths, and a corresponding better uniformity of SOL plasma parameters. Asymmetry of electron density is observed, which can be associated with the recycling of plasma near the toroidal limiter plates in a configuration with long connection lengths. Electron temperature appears to be less dependent of power entering the SOL than in the old poloidal limiter configuration. Experimentally observed dependence of the edge plasma condition on Lcon has been confirmed by the results of the 2D code EPIT.

  15. Structural morphological and optoelectronic study of titania and gold doped titania nanoparticles grown by sol-gel technique

    NASA Astrophysics Data System (ADS)

    Jadhav, Yogesh A.; Gattu, Ketan P.; Ghule, Anil; Sharma, Ramphal

    2013-02-01

    Here in this work, the titania (TiO2), gold ion doped titania (Au+3TiO2) and gold nanoparticles doped titania (Au NPs TiO2) have been prepared by sol-gel technique. In a typical synthesis titanium tetrachloride (TiCl4) is treated with citric acid in presence of methanol as solvents, forms titanium citrate complex sol at 40°C. This sol forms a viscous gel after 2 h of stirring and heating at 60 °C. The pre-synthesized Au+3 ions and Au NPs were then added drop wise to the titanium citrate complex sol to form gold ion doped titania (Au+3TiO2) and gold nanoparticles doped titania. The products obtained were calcined at 700 °C. The obtained particles were studied for their structural, morphological, optical and electrical properties.

  16. Increasing the activity and enantioselectivity of lipases by sol-gel immobilization: further advancements of practical interest

    NASA Astrophysics Data System (ADS)

    Tielmann, Patrick; Kierkels, Hans; Zonta, Albin; Ilie, Adriana; Reetz, Manfred T.

    2014-05-01

    The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of the sol-gel approach.The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of

  17. Les recommandations thérapeutiques relatives aux effets secondaires extrapyramidaux associés à l’utilisation d’antipsychotiques de deuxième génération chez les enfants et les adolescents

    PubMed Central

    Pringsheim, Tamara; Doja, Asif; Belanger, Stacey; Patten, Scott

    2012-01-01

    HISTORIQUE ET OBJECTIF : L’utilisation d’antipsychotiques augmente chez les enfants. Le présent article visait à orienter les cliniciens quant à la prise en charge clinique des effets secondaires extrapyramidaux des antipsychotiques de deuxième génération. MÉTHODOLOGIE : Les publications, les entrevues avec des informateurs clés et des échanges avec les membres d’un groupe de discussion et les partenaires ont permis de déterminer les principaux secteurs cliniques d’orientation et les préférences quant à la structure des présentes recommandations. Les membres responsables des lignes directrices ont reçu le projet de recommandations, ont évalué l’information recueillie grâce à une analyse bibliographique systématique et ont utilisé un processus de groupe nominal pour parvenir à un consensus quant aux recommandations thérapeutiques. Les lignes directrices contiennent une description des anomalies neurologiques souvent observées avec l’utilisation d’antipsychotiques ainsi que les recommandations sur le moyen d’examiner et de quantifier ces anomalies. Une démarche séquentielle sur la prise en charge des anomalies neurologiques est présentée. RÉSULTATS : On peut observer plusieurs types de symptômes extrapyramidaux attribuables à l’utilisation d’antipsychotiques chez les enfants, y compris la dystonie aiguë, l’akathisie, le parkinsonisme et la dyskinésie tardive, toutes induites par les neuroleptiques, de même que la dystonie tardive, l’akathisie tardive et les dyskinésies de sevrage. La forte majorité des données probantes sur le traitement des troubles du mouvement induits par les antipsychotiques proviennent de patients adultes atteints de schizophrénie. Étant donné le peu de données pédiatriques, les recommandations découlent de publications portant tant sur des adultes que sur des enfants. Compte tenu des limites de généralisation des données provenant de sujets adultes pour des enfants, il

  18. Sol-gel nanocasting synthesis of patterned hierarchical LaFeO3 fibers with enhanced catalytic CO oxidation activity.

    PubMed

    Li, Pengna; Hu, Xianluo; Zhang, Lei; Dai, Hongxing; Zhang, Lizhi

    2011-03-01

    Hierarchical LaFeO3 fibers were prepared by a sol-gel nanocasting method using a cotton cloth as the template. The resulting LaFeO3 fibers inherited the initial network morphology of the template very well and showed enhanced catalytic CO oxidation activity and satisfactory stability compared to the counterpart particles prepared by the conventional sol-gel method. PMID:21234504

  19. Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

    PubMed

    Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G

    2016-03-31

    Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and

  20. Optical and morphological properties of sol gel derived titanium dioxide films

    SciTech Connect

    Sharma, A. B.; Sharma, S. K.; M, Vishwas; Rao, K. Narasimha

    2015-08-28

    Titanium oxide (Titania) thin films were synthesized on different substrates via the sol-gel dip-coating method using alkoxide solution. Some selected samples were also prepared with different percentage of Lead (Pb). The influence of Pb addition in precursor sol on the optical properties of titanium dioxide thin films was studied. The optical transmittance in the visible region has increased with increase in weight percentage of lead. The refractive index was slightly decreased with Pb addition. Crystallization of these coatings was achieved through thermal annealing at temperatures above 400 °C. The structural properties and surface morphology of the crystallized coatings were studied by Scanning Electron Microscopy. Increase in average grain size from 250 nm to 350 nm with increase in Pb concentration is observed. Films were appeared to more coarse with increase in Pb addition. An increase in Pb addition resulted increase in average roughness from 12 nm to 25 nm.

  1. Wall surface temperature calculation in the SolEdge2D-EIRENE transport code

    NASA Astrophysics Data System (ADS)

    Denis, J.; Pégourié, B.; Bucalossi, J.; Bufferand, H.; Ciraolo, G.; Gardarein, J.-L.; Gaspar, J.; Grisolia, C.; Hodille, E.; Missirlian, M.; Serre, E.; Tamain, P.

    2016-02-01

    A thermal wall model is developed for the SolEdge2D-EIRENE edge transport code for calculating the surface temperature of the actively-cooled vessel components in interaction with the plasma. This is a first step towards a self-consistent evaluation of the recycling of particles, which depends on the wall surface temperature. The proposed thermal model is built to match both steady-state temperature and time constant of actively-cooled plasma facing components. A benchmark between this model and the Finite Element Modelling code CAST3M is performed in the case of an ITER-like monoblock. An example of application is presented for a SolEdge2D-EIRENE simulation of a medium-power discharge in the WEST tokamak, showing the steady-state wall temperature distribution and the temperature cycling due to an imposed Edge Localised Mode-like event.

  2. Sol-gel coatings for high power laser optics-past, present and future

    SciTech Connect

    Thomas, I.M.

    1993-12-21

    An investigation into the preparation of sol-gel coatings for high power lasers was started at LLNL in 1983 and AR coatings were successfully developed for use in the Nova laser in 1984. Several other large lasers now use these coatings. Subsequent work on HR coatings resulted in AlOOH/SiO{sub 2} and later ZrO{sub 2} or HfO{sub 2}/SiO{sub 2} systems of good optical performance. The use of organic polymer binders gave increased damage threshold and enhanced optical performance. We are in the process of scaling up HR fabrication for substrates approximately 38 cm square. Concurrently we are developing sol-gel random phase plates for laser beam smoothing. These have a patterned surface design of silica which induces phase shifts in the beam by variation in the optical path length. Plates of this type on 80 cm diameter substrates have been used successfully on the Nova.

  3. Moisture sensor based on evanescent wave light scattering by porous sol-gel silica coating

    DOEpatents

    Tao, Shiquan; Singh, Jagdish P.; Winstead, Christopher B.

    2006-05-02

    An optical fiber moisture sensor that can be used to sense moisture present in gas phase in a wide range of concentrations is provided, as well techniques for making the same. The present invention includes a method that utilizes the light scattering phenomenon which occurs in a porous sol-gel silica by coating an optical fiber core with such silica. Thus, a porous sol-gel silica polymer coated on an optical fiber core forms the transducer of an optical fiber moisture sensor according to an embodiment. The resulting optical fiber sensor of the present invention can be used in various applications, including to sense moisture content in indoor/outdoor air, soil, concrete, and low/high temperature gas streams.

  4. Regioselective hydroaminomethylation of vinylarenes by a sol-gel immobilized rhodium catalyst.

    PubMed

    Nairoukh, Zackaria; Blum, Jochanan

    2014-03-21

    In the course of our studies toward the development of new heterogeneous conditions for better controlling regioselectivity in organic reactions, we investigated the application of sol-gel immobilized organometallic catalyst for regioselective hydroaminomethylation of vinylarenes with aniline or nitroarene derivatives in an aqueous microemulsion. By immobilization of 6 mol % [Rh(cod)Cl]2 within a hydrophobic silica sol-gel matrix we were able to perform efficient hydroaminomethylation under mild conditions and isolate 2-arylpropylamines with high regioselectivity. The regioselectivity of the reaction was found to be mainly dependent on the hydrophobicity of the catalyst support. It is also significantly affected by the electronic nature of the substrates, by the reaction temperature, and by syngas pressure. The heterogenized catalyst can be reused for several times. PMID:24528141

  5. Multi-level diffractive optical elements produced by excimer laser ablation of sol-gel.

    PubMed

    Neiss, Estelle; Flury, Manuel; Mager, Loïc; Rehspringer, Jean-Luc; Fort, Alain; Montgomery, Paul; Gérard, Philippe; Fontaine, Joël; Robert, Stéphane

    2008-09-01

    Material ablation by excimer laser micromachining is a promising approach for structuring sol-gel materials as we demonstrate in the present study. Using the well-known direct etching technique, the behaviour of different hybrid organic/inorganic self-made sol-gel materials is examined with a KrF* laser. Ablated depths ranging from 0.1 to 1.5 microm are obtained with a few laser pulses at low fluence (< 1 J/cm(2)). The aim is to rapidly transfer surface relief multi-level diffractive patterns in such a substrate, without intermediate steps. The combination with the 3D profilometry technique of coherence probe microscopy permits to analyse the etching process with the aim of producing multi-level Diffractive Optical Elements (DOE). Examples of four-level DOEs with 10 microm square elementary cells are presented, as well as their laser reconstructions in the infrared. PMID:18773015

  6. The Physics of Evaporation-Induced Assembly of Sol-Gel Materials

    SciTech Connect

    HURD,ALAN J.; STEINBERG,LEV

    2000-07-24

    Remarkable materials ordered at the nanoscale emerge when a sol-gel solution becomes co-organized with a surfactant. At sufficiently high concentration, the surfactant forms crystalline or liquid-crystalline arrays of micelles in the presence of the sol-gel, and as gelation proceeds the arrays become locked into the gel. Recent experiments demonstrate that the degree of order in the resulting mesoporous ceramic phase can be enhanced and controlled by continuous dip coating in which the solution, initially dilute, evolves through the critical micelle concentration by steady-state evaporation. The long-range order and microstructural orientation in these films suggest that the propagation of a critical-micelle-concentration transition front, with large physico-chemical gradients, promotes oriented self assembly of surfactant aggregates. This steep-gradient view is supported by results from unsteady evaporation of aerosols of similar solutions, in which internally well-ordered but complex particles are formed.

  7. Reversible Gel-Sol Transition of a Photo-Responsive DNA Gel.

    PubMed

    Kandatsu, Daisuke; Cervantes-Salguero, Keitel; Kawamata, Ibuki; Hamada, Shogo; Nomura, Shin-Ichiro M; Fujimoto, Kenzo; Murata, Satoshi

    2016-06-16

    Stimuli-responsive DNA gels that can undergo a sol-gel transition in response to photo-irradiation provide a way to engineer functional gel material with fully designed DNA base sequences. We propose an X-shaped DNA motif that turns into a gel by hybridization of self-complementary sticky ends. By embedding a photo-crosslinking artificial base in the sticky-end sequence, repetitive gel-sol transitions are achieved through UV irradiation at different wavelengths. The concentration of the DNA motif necessary for gelation is as low as 40 μm after modification of the geometrical properties of the motif. The physical properties, such as swelling degree and diffusion coefficient, were assessed experimentally. PMID:27123549

  8. Sol-gel co-assembly of hollow cylindrical inverse opals and inverse opal columns.

    PubMed

    Haibin, Ni; Ming, Wang; Wei, Chen

    2011-12-19

    A facile approach of fabricating hollow cylindrical inverse opals and inverse opal columns by sol-gel co-assembly method was proposed. Polystyrene (PS) colloidal suspension added with hydrolyzed silicate precursor solution was used to self-assemble composite colloidal crystals which consist of PS colloidal crystal template and infiltrated silica gel in the interstitial of microspheres. Continuous hollow cylindrical composite colloidal crystal films have been produced on capillaries' outside and internal surface. Composite colloidal crystal columns which filling up the interior of a capillary were fabricated by pressure assisted sol-gel co-assembly method. Hollow cylindrical inverse opals and inverse opal columns were obtained after removing PS colloidal crystal from the composite colloidal crystal. Optical properties of the silica hollow cylindrical inverse opals were characterized by transmission spectrum and a stop band was observed. Structure and optical properties of the inverse opal columns were investigated. PMID:22274178

  9. SolTrace: A Ray-Tracing Code for Complex Solar Optical Systems

    SciTech Connect

    Wendelin, Tim; Dobos, Aron; Lewandowski, Allan

    2013-10-01

    SolTrace is an optical simulation tool designed to model optical systems used in concentrating solar power (CSP) applications. The code was first written in early 2003, but has seen significant modifications and changes since its inception, including conversion from a Pascal-based software development platform to C++. SolTrace is unique in that it can model virtually any optical system utilizingthe sun as the source. It has been made available for free and as such is in use worldwide by industry, universities, and research laboratories. The fundamental design of the code is discussed, including enhancements and improvements over the earlier version. Comparisons are made with other optical modeling tools, both non-commercial and commercial in nature. Finally, modeled results are shownfor some typical CSP systems and, in one case, compared to measured optical data.

  10. A Review of Photocatalysts Prepared by Sol-Gel Method for VOCs Removal

    PubMed Central

    Tseng, Ting Ke; Lin, Yi Shing; Chen, Yi Ju; Chu, Hsin

    2010-01-01

    The sol-gel process is a wet-chemical technique (chemical solution deposition), which has been widely used in the fields of materials science, ceramic engineering, and especially in the preparation of photocatalysts. Volatile organic compounds (VOCs) are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO) is regarded as a promising method. This paper is a review of the status of research on the sol-gel method for photocatalyst preparation and for the PCO purification of VOCs. The review and discussion will focus on the preparation and coating of various photocatalysts, operational parameters, and will provide an overview of general PCO models described in the literature. PMID:20640156

  11. Glucose microbiosensor based on alumina sol-gel matrix/electropolymerized composite membrane.

    PubMed

    Chen, Xiaohong; Hu, Yibai; Wilson, George S

    2002-12-01

    A procedure is described that provides co-immobilization of enzyme and bovine serum albumin (BSA) within an alumina sol-gel matrix and a polyphenol layer permselective for endogenous electroactive species. BSA has first been employed for the immobilization of glucose oxidase (GOx) on a Pt electrode in a sol-gel to produce a uniform, thin and compact film with enhanced enzyme activity. Electropolymerization of phenol was then employed to form an anti-interference and protective polyphenol film within the enzyme layer. In addition, a stability-reinforcing membrane derived from (3-aminopropyl)-trimethoxysilane was constructed by electrochemically-assisted crosslinking. This hybrid film outside the enzyme layer contributed both to the improved stability and to permselectivity. The resulting glucose sensor was characterized by a short response time (<10 s), high sensitivity (10.4 nA/mM mm(2)), low interference from endogenous electroactive species, and a working lifetime of at least 60 days. PMID:12392950

  12. First results of the SOL reflectometer on Alcator C-Mod.

    PubMed

    Lau, C; Hanson, G; Lin, Y; Wilgen, J; Wukitch, S; Labombard, B; Wallace, G

    2012-10-01

    A swept-frequency X-mode reflectometer has been built on Alcator C-Mod to measure the scrape-off layer (SOL) density profiles adjacent to the lower hybrid launcher. The reflectometer system operates between 100 and 146 GHz at sweep rates from 10 μs to 1 ms and covers a density range of ∼10(16)-10(20) m(-3) at B(0) = 5-5.4 T. This paper discusses the analysis of reflectometer density profiles and presents first experimental results of SOL density profile modifications due to the application of lower hybrid range-of-frequencies power to L-mode discharges. Comparison between density profiles measured by the X-mode reflectometer and scanning Langmuir probes is also shown. PMID:23126969

  13. First results of the SOL reflectometer on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Lau, C.; Hanson, G.; Lin, Y.; Wilgen, J.; Wukitch, S.; Labombard, B.; Wallace, G.

    2012-10-01

    A swept-frequency X-mode reflectometer has been built on Alcator C-Mod to measure the scrape-off layer (SOL) density profiles adjacent to the lower hybrid launcher. The reflectometer system operates between 100 and 146 GHz at sweep rates from 10 μs to 1 ms and covers a density range of ˜1016-1020 m-3 at B0 = 5-5.4 T. This paper discusses the analysis of reflectometer density profiles and presents first experimental results of SOL density profile modifications due to the application of lower hybrid range-of-frequencies power to L-mode discharges. Comparison between density profiles measured by the X-mode reflectometer and scanning Langmuir probes is also shown.

  14. Sol gel based fiber optic sensor for blook pH measurement

    SciTech Connect

    Grant, S. A.; Glass, R. S.

    1996-12-19

    This paper describes a fiber-optic pH sensor based upon sol-gel encapsulation of a self-referencing dye, seminaphthorhodamine-1 carboxylate (SNARF-1C). The simple sol-gel fabrication procedure and low coating leachability are ideal for encapsulation and immobilization of dye molecules onto the end of an optical fiber. A miniature bench-top fluorimeter system was developed for use with the optical fiber to obtain pH measurements. Linear and reproducible responses were obtained in human blood in the pH range 6.8 to 8.0, which encompasses the clinically-relevant range. Therefore, this sensor can be considered for in vivo use.

  15. Sol processing of conjugated carbon nitride powders for thin-film fabrication.

    PubMed

    Zhang, Jinshui; Zhang, Mingwen; Lin, Lihua; Wang, Xinchen

    2015-05-18

    The chemical protonation of graphitic carbon nitride (CN) solids with strong oxidizing acids, for example HNO3, is demonstrated as an efficient pathway for the sol processing of a stable CN colloidal suspension, which can be translated into thin films by dip/disperse-coating techniques. The unique features of CN colloids, such as the polymeric matrix and the reversible hydrogen bonding, result in the thin-film electrodes derived from the sol solution exhibiting a high mechanical stability with improved conductivity for charge transport, and thus show a remarkably enhanced photo-electrochemical performance. The polymer system can in principle be broadly tuned by hybridization with desired functionalities, thus paving the way for the application of CN for specific tasks, as exemplified here by coupling with carbon nanotubes. PMID:25833791

  16. Metal mediated sol-gel chemistry of 1,2-Bis(triethoxysilyl)-ethene

    SciTech Connect

    Carpenter, J.P.; Yamanaka, S.A.; McClain, M.D.

    1996-10-01

    Ethenyl-bridged polysilsesquioxane xerogels and aerogels were formed from the sol-gel polymerization of 1,2-bis(triethoxysilyl)ethene. Gels were synthesized from the cis- and trans-isomers by both acid and base catalysis. While the trans-monomer exhibited relatively fast gelation times, the cis-monomer depending on the conditions either formed no gel of had very long gelation times. The addition of a coordinating metal such as Pd to the cis-monomer sol results in dramatically decreased gelation times. The addition of salts with noncoordinating metals did not significantly shorten the gelation times indicating that a template effect may be directing the polymerization of the cis-monomer. The ethenyl-bridged polysilsesquioxanes were characterized by solid state {sup 29}Si and {sup 13}C NMR, nitrogen sorption porosimetry, and transmission electron microscopy.

  17. Surface aspects of sol-gel derived hematite films for the photoelectrochemical oxidation of water.

    PubMed

    Herrmann-Geppert, Iris; Bogdanoff, Peter; Radnik, Jörg; Fengler, Steffen; Dittrich, Thomas; Fiechter, Sebastian

    2013-02-01

    α-Fe(2)O(3) (hematite) photoanodes for the oxygen evolution reaction (OER) were prepared by a cost-efficient sol-gel procedure. Due to low active photoelectrochemical properties observed, it is assumed that the sol-gel procedure leads to hematite films with defects and surface states on which generated charge carriers are recombined or immobilized in trap processes. Electrochemical activation was proven to diminish unfavourable surface groups to some extent. More efficiently, a plasma treatment improves significantly the photoelectrochemical properties of the OER. X-ray photoelectron spectroscopy (XPS) analysis reveals an oxygen enriched surface layer with new oxygen species which may be responsible for the improved electrochemical activity. Due to surface photovoltage an increased fraction of transferred charge carriers from these newly produced surface defects are identified. PMID:23247669

  18. Solid-state NMR study of geopolymer prepared by sol-gel chemistry

    SciTech Connect

    Tsai, Yi-Ling; Hanna, John V.; Lee, Yuan-Ling; Smith, Mark E.; Chan, Jerry C.C.

    2010-12-15

    Geopolymers are a new class of materials formed by the condensation of aluminosilicates and silicates obtained from natural minerals or industrial wastes. In this work, the sol-gel method is used to synthesize precursor materials for the preparation of geopolymers. The geopolymer samples prepared by our synthetic route have been characterized by a series of physical techniques, including Fourier-transform infrared, X-ray diffraction, and multinuclear solid-state NMR. The results are very similar to those obtained for the geopolymers prepared from natural kaolinite. We believe that our synthetic approach can offer a good opportunity for the medical applications of geopolymer. -- Graphical abstract: Geopolymer prepared by the sol-gel route has the same spectroscopic properties as the sample prepared from the natural kaolinite. Display Omitted

  19. Effect of sol-gel modifications on formation and morphology of nanocrystalline lanthanum aluminate

    SciTech Connect

    Koc, S. Naci . E-mail: nacik@istanbul.edu.tr; Oksuzomer, Faruk; Yasar, Erdem; Akturk, Selcuk; Gurkaynak, M. Ali

    2006-12-14

    LaAlO{sub 3} powders are prepared by sol-gel method. The effect of preparation conditions on morphological properties and crystal formations are investigated. iso-Propanol/tert-butanol and ethyl acetoacetate/ethylene glycol monomethylether are used solvents and complexing agents, respectively. Samples are dried with conventional and freeze-drying methods and calcined between 600 and 1000 deg. C. TGA, DTA, XRD, SEM and TEM methods are used for characterization. It is observed that freeze-dried sample prepared with tert-butanol has the lowest LaAlO{sub 3} formation temperature and uniform rhombohedral crystals. But conventionally dried sample, prepared with iso-propanol has smallest agglomerates at 1000 deg. C and does not show clear crystallization temperature in DTA analysis. The XRD peaks of LaAlO{sub 3} crystal are observed at 600 deg. C for all samples prepared by various sol-gel conditions.

  20. Sol-gel/rhodamine 6G composite films with tailored microstructures

    SciTech Connect

    Logan, D.L.; Ashley, C.S.; Assink, R.A.; Brinker, C.J. |

    1992-12-31

    A multi-step hydrolysis procedure was developed to prepare composite organic dye/sol-gel thin films with variable porosity for such as switches or sensors. Variation of acid and base catalyzed hydrolysis sequences of three sols prepared from tetraethoxysilane with identical H{sub 2}O/Si ratios, dilution factors, and pH resulted in considerably different silicate speciation. Under conditions where monomer was avoided, the refractive indices of as-deposited films could be varied by an again step prior to film deposition. This general strategy, which relies on the aggregation of fractal polymeric clusters, is compatible with the low temperature and near neutral pH requirements of both organic dyes and biologically active species such as enzymes.