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Sample records for titanate coatings applied

  1. Barium titanate coated with magnesium titanate via fused salt method and its dielectric property

    International Nuclear Information System (INIS)

    Chen Renzheng; Cui Aili; Wang Xiaohui; Li Longtu

    2003-01-01

    Barium titanate fine particles were coated homogeneously with magnesium titanate via the fused salt method. The thickness of the magnesium titanate film is 20 nm, as verified by TEM and XRD. The mechanism of the coating is that: when magnesium chloride is liquated in 800 deg. C, magnesium will replace barium in barium titanate, and form magnesium titanate film on the surface of barium titanate particles. Ceramics sintered from the coated particles show improved high frequency ability. The dielectric constant is about 130 at the frequency from 1 to 800 MHz

  2. Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Barenghi, R. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Farkas, B.; Romano, I. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scaglione, S. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Brandi, F. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, 56124-Pisa (Italy)

    2014-11-01

    The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation.

  3. Titanate nanotube coatings on biodegradable photopolymer scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

    2013-05-01

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

  4. Application of electroless Ni-P coating on magnesium alloy via CrO3/HF free titanate pretreatment

    Science.gov (United States)

    Rajabalizadeh, Z.; Seifzadeh, D.

    2017-11-01

    The titanate conversion coating was applied as CrO3/HF free pretreatment for the electroless Ni-P plating on AM60B magnesium alloy. The microscopic images revealed that the alloy surface was completely covered by a cracked conversion film after titanate pretreatment which was mainly composed of Mg(OH)2/MgO, MgF2, TiO2, SiO2, and Al2O3/Al(OH)3. The microscopic images also revealed that numerous Ni nucleation centers were formed over the titanate film after short electroless plating times. The nucleation centers were created not only on the cracked area but also over the whole pretreated surface due to the catalytic action of the titanate film. Also, uniform, dense, and defect-free Ni-P coating with fine structure was achieved after 3 h plating. The Ni-P coating showed mixed crystalline-amorphous structure due to its moderate phosphorus content. The results of two traditional corrosion monitoring methods indicated that the Ni-P coating significantly increases the corrosion resistance of the magnesium alloy. Moreover, Electrochemical Noise (EN) method was used as a non-polarized technique to study the corrosion behavior of the electroless coating at different immersion times. The results of the EN tests were clearly showed the localized nature of the corrosion process. Micro-hardness value of the magnesium alloy was remarkably enhanced after the electroless plating. Finally, suitable adhesion between the Ni-P coating and the magnesium alloy substrate was confirmed by thermal shock and pull-off-adhesion tests.

  5. Enhanced Rate Capability of Oxide Coated Lithium Titanate within Extended Voltage Ranges

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Dongjoon [College of Engineering, University of Kentucky, Lexington, KY (United States); Xiao, Xingcheng, E-mail: xingcheng.xiao@gm.com [Chemical and Materials Systems Laboratory, General Motors R& D Center, Warren, MI (United States)

    2015-06-30

    Lithium titanate (Li{sub 4}Ti{sub 5}O{sub 12} or LTO) is a promising negative electrode material of high-power lithium-ion batteries, due to its superior rate capability and excellent capacity retention. However, the specific capacity of LTO is less than one half of that of graphite electrode. In this work, we applied ultrathin oxide coating on LTO by the atomic layer deposition technique, aiming for increasing the energy density by extending the cell voltage window and specific capacity of LTO. We demonstrated that a few nanometer thick Al{sub 2}O{sub 3} coating can suppress the mechanical distortion of LTO cycled at low potential, which enable the higher specific capacity and excellent capacity retention. Furthermore, the surface coating can facilitate the charge transfer, leading to significantly improved rate capabilities, comparing with the uncoated LTO.

  6. Adherence and electrochemical behavior of calcium titanate coatings onto 304 stainless steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Esguerra A, J.; Aguilar, Y. [Universidad del Valle, Escuela de Ingenieria de Materiales, TPMR, Calle 13 No. 100-00, A. A. 25360 Cali (Colombia); Aperador, W. [Escuela Colombiana de Ingenieria Julio Garavito, Escuela de Ingenieria Mecanica, AK 45 No. 205-59 (Autopista Norte), A. A. 14520 Bogota (Colombia); Alba de Sanchez, N. [Universidad Autonoma de Occidente, Grupo de Investigacion en Ciencia e Ingenieria de Materiales, Calle 25 No. 115-85, A. A. 2790 Cali (Colombia); Bolanos P, G.; Rincon, C., E-mail: johanna.esguerra@univalle.edu.co [Universidad del Cauca, Departamento de Fisica, Laboratorio de Fisica de Bajas Temperaturas, Calle 5 No. 4-70, A. A. 996 Popayan (Colombia)

    2014-07-01

    Calcium titanate has been proposed as a coating for biomedical applications but it has not been reported characterization of adhesion failure mechanisms or electrochemical properties in time. In this work have been studied these properties of a calcium titanate coating growth onto AISI 304 steel deposited by r.f. magnetron sputtering. It was found that the coating has a critical adhesive load of 6.53 ± 0.14 N. With respect to its electrochemical properties potentiodynamic polarization curves show that the calcium titanate coating provides protection to AISI 304 steel. However. EIS indicates that even though metal dissolution occur through the pores in the coating, this leads to the precipitation of salts that block pores; this precipitates layer acts like and additional barrier to the metal dissolution in the system. The coatings deposition was carried out via magnetron sputtering during 4 hours at 500 grades C. The crystal structure of the films was determined by using glancing incident X-ray diffraction. The chemical composition of deposited films was performed by impedance dispersive X-ray spectroscopy (EDX) in the scanning electron microscopy (Jeol JSM-649 OLV Sem), and the grain size and the roughness was obtained using an atomic force microscopy from Asylum Research MFP-3D using a cantilever silicon tip in non-contact mode and calculated by scanning probe image processor. (Author)

  7. Adherence and electrochemical behavior of calcium titanate coatings onto 304 stainless steel substrate

    International Nuclear Information System (INIS)

    Esguerra A, J.; Aguilar, Y.; Aperador, W.; Alba de Sanchez, N.; Bolanos P, G.; Rincon, C.

    2014-01-01

    Calcium titanate has been proposed as a coating for biomedical applications but it has not been reported characterization of adhesion failure mechanisms or electrochemical properties in time. In this work have been studied these properties of a calcium titanate coating growth onto AISI 304 steel deposited by r.f. magnetron sputtering. It was found that the coating has a critical adhesive load of 6.53 ± 0.14 N. With respect to its electrochemical properties potentiodynamic polarization curves show that the calcium titanate coating provides protection to AISI 304 steel. However. EIS indicates that even though metal dissolution occur through the pores in the coating, this leads to the precipitation of salts that block pores; this precipitates layer acts like and additional barrier to the metal dissolution in the system. The coatings deposition was carried out via magnetron sputtering during 4 hours at 500 grades C. The crystal structure of the films was determined by using glancing incident X-ray diffraction. The chemical composition of deposited films was performed by impedance dispersive X-ray spectroscopy (EDX) in the scanning electron microscopy (Jeol JSM-649 OLV Sem), and the grain size and the roughness was obtained using an atomic force microscopy from Asylum Research MFP-3D using a cantilever silicon tip in non-contact mode and calculated by scanning probe image processor. (Author)

  8. Titan

    Science.gov (United States)

    Müller-Wodarg, Ingo; Griffith, Caitlin A.; Lellouch, Emmanuel; Cravens, Thomas E.

    2014-03-01

    Introduction I. C. F. Müller-Wodarg, C. A. Griffith, E. Lellouch and T. E. Cravens; Prologue 1: the genesis of Cassini-Huygens W.-H. Ip, T. Owen and D. Gautier; Prologue 2: building a space flight instrument: a P.I.'s perspective M. Tomasko; 1. The origin and evolution of Titan G. Tobie, J. I. Lunine, J. Monteux, O. Mousis and F. Nimmo; 2. Titan's surface geology O. Aharonson, A. G. Hayes, P. O. Hayne, R. M. Lopes, A. Lucas and J. T. Perron; 3. Thermal structure of Titan's troposphere and middle atmosphere F. M. Flasar, R. K. Achterberg and P. J. Schinder; 4. The general circulation of Titan's lower and middle atmosphere S. Lebonnois, F. M. Flasar, T. Tokano and C. E. Newman; 5. The composition of Titan's atmosphere B. Bézard, R. V. Yelle and C. A. Nixon; 6. Storms, clouds, and weather C. A. Griffith, S. Rafkin, P. Rannou and C. P. McKay; 7. Chemistry of Titan's atmosphere V. Vuitton, O. Dutuit, M. A. Smith and N. Balucani; 8. Titan's haze R. West, P. Lavvas, C. Anderson and H. Imanaka; 9. Titan's upper atmosphere: thermal structure, dynamics, and energetics R. V. Yelle and I. C. F. Müller-Wodarg; 10. Titan's upper atmosphere/exosphere, escape processes, and rates D. F. Strobel and J. Cui; 11. Titan's ionosphere M. Galand, A. J. Coates, T. E. Cravens and J.-E. Wahlund; 12. Titan's magnetospheric and plasma environment J.-E. Wahlund, R. Modolo, C. Bertucci and A. J. Coates.

  9. Formation of layer-by-layer assembled titanate nanotubes filled coating on flexible polyurethane foam with improved flame retardant and smoke suppression properties.

    Science.gov (United States)

    Pan, Haifeng; Wang, Wei; Pan, Ying; Song, Lei; Hu, Yuan; Liew, Kim Meow

    2015-01-14

    A fire blocking coating made from chitosan, titanate nanotubes and alginate was deposited on a flexible polyurethane (FPU) foam surface by a layer-by-layer assembly technique in an effort to reduce its flammability. First, titanate nanotubes were prepared by a hydrothermal method. And then the coating growth was carried out by alternately submerging FPU foams into chitosan solution, titanate nanotubes suspension and alginate solution. The mass gain of coating on the surface of FPU foams showed dependency on the concentration of titanate nanotubes suspension and the trilayers's number. Scanning electron microscopy indicated that titanate nanotubes were distributed well on the entire surface of FPU foam and showed a randomly oriented and entangled network structure. The cone calorimeter result indicated that the coated FPU foams showed reduction in the peak heat release rate (peak HRR), peak smoke production rate (peak SPR), total smoke release (TSR) and peak carbon monoxide (CO) production compared with those of the control FPU foam. Especially for the FPU foam with only 5.65 wt % mass gain, great reduction in peak HRR (70.2%), peak SPR (62.8%), TSR (40.9%) and peak CO production (63.5%) could be observed. Such a significant improvement in flame retardancy and the smoke suppression property for FPU foam could be attributed to the protective effect of titanate nanotubes network structure formed, including insulating barrier effect and adsorption effect.

  10. Visible-light photochemical activity of heterostructured core-shell materials composed of selected ternary titanates and ferrites coated by tiO2.

    Science.gov (United States)

    Li, Li; Liu, Xuan; Zhang, Yiling; Nuhfer, Noel T; Barmak, Katayun; Salvador, Paul A; Rohrer, Gregory S

    2013-06-12

    Heterostructured photocatalysts comprised of microcrystalline (mc-) cores and nanostructured (ns-) shells were prepared by the sol-gel method. The ability of titania-coated ATiO3 (A = Fe, Pb) and AFeO3 (A = Bi, La, Y) catalysts to degrade methylene blue in visible light (λ > 420 nm) was compared. The catalysts with the titanate cores had enhanced photocatalytic activities for methylene blue degradation compared to their components alone, whereas the catalysts with ferrite cores did not. The temperature at which the ns-titania shell is crystallized influences the photocatalytic dye degradation. mc-FeTiO3/ns-TiO2 annealed at 500 °C shows the highest reaction rate. Fe-doped TiO2, which absorbs visible light, did not show enhanced photocatalytic activity for methylene blue degradation. This result indicates that iron contamination is not a decisive factor in the reduced reactivity of the titania coated ferrite catalysts. The higher reactivity of materials with the titanate cores suggests that photogenerated charge carriers are more easily transported across the titanate-titanate interface than the ferrite-titanate interface and this provides guidance for materials selection in composite catalyst design.

  11. Titan's Ammonia Feature

    Science.gov (United States)

    Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

    2011-01-01

    NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

  12. Synthesis and silica coating of calcia-doped ceria/plate-like titanate (K0.8Li0.27Ti1.73O4) nanocomposite by seeded polymerization technique

    International Nuclear Information System (INIS)

    El-Toni, Ahmed Mohamed; Yin, Shu; Sato, Tsugio

    2007-01-01

    Calcia-doped ceria is of potential interest as an ultraviolet (UV) radiation blocking material in personal care products because of the excellent UV light absorption property and low catalytic ability for the oxidation of organic materials superior to undoped ceria. In order to reduce the oxidation catalytic activity further, calcia-doped ceria was coated with amorphous silica by means of seeded polymerization technique. Generally, nanoparticles of inorganic materials do not provide a good coverage for human skin because of the agglomeration of the particles. The plate-like particles are required to enhance the coverage ability of inorganic materials. This can be accomplished by synthesis of calcia-doped ceria/plate-like potassium lithium titanate (K 0.8 Li 0.27 Ti 1.73 O 4 ) nanocomposite with subsequent silica coating to control catalytic activity of calcia-doped ceria. Calcia-doped ceria/plate-like potassium lithium titanate nanocomposite was prepared by soft chemical method followed by silica coating via seeded polymerization technique. Silica coated calcia-doped ceria/plate-like potassium lithium titanate nanocomposite was characterized by X-ray diffraction, SEM, TEM, XPS and FT-IR

  13. Enhanced biocompatibility and osseointegration of calcium titanate coating on titanium screws in rabbit femur.

    Science.gov (United States)

    Wang, Zi-Li; He, Rong-Zhen; Tu, Bin; Cao, Xu; He, Jin-Shen; Xia, Han-Song; Liang, Chi; Zou, Min; Wu, Song; Wu, Zhen-Jun; Xiong, Kun

    2017-06-01

    This study aimed to examine the biocompatibility of calcium titanate (CaTiO 3 ) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO 3 coating as an alternative to current implant coating materials. CaTiO 3 -coated titanium screws were implanted with hydroxyapatite (HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO 3 were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO 3 -coated screws. X-ray imaging analysis showed in the CaTiO 3 coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO 3 coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO 3 coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.

  14. Comparison of barium titanate thin films prepared by inkjet printing and spin coating

    Directory of Open Access Journals (Sweden)

    Jelena Vukmirović

    2015-09-01

    Full Text Available In this paper, barium titanate films were prepared by different deposition techniques (spin coating, office Epson inkjet printer and commercial Dimatix inkjet printer. As inkjet technique requires special rheological properties of inks the first part of the study deals with the preparation of inks, whereas the second part examines and compares structural characteristics of the deposited films. Inks were synthesized by sol-gel method and parameters such as viscosity, particle size and surface tension were measured. Deposited films were examined by optical and scanning electron microscopy, XRD analysis and Raman spectroscopy. The findings consider advantages and disadvantages of the particular deposition techniques.

  15. Advanced ceramic coating development for industrial/utility gas turbines. Final report, 11 Mar 1979-1 Sep 1981

    International Nuclear Information System (INIS)

    Vogan, J.W.; Stetson, A.R.

    1982-01-01

    A program was conducted with the objective of developing advanced thermal barrier coating (TBC) systems. Coating application was by plasma spray. Duplex, triplex and graded coatings were tested. Coating systems incorporated both NiCrAly and CoCrAly bond coats. Four ceramic overlays were tested: ZrO 2 .82O 3 , CaO.TiO 2 , 2CaO.SiO 2 , and MgO.Al 2 O 3 . The best overall results were obtained with a CaO.TiO 2 coating applied to a NiCrAly bond coat. This coating was less sensitive than the ZrO 2 .8Y 2 O 3 coating to process variables and part geometry. Testing with fuels contaminated with compounds containing sulfur, phosphorus and alkali metals showed the zirconia coatings were destabilized. The calcium titanate coatings were not affected by these contaminants. However, when fuels were used containing 50 ppm of vanadium and 150 ppm of magnesium, heavy deposits were formed on the test specimens and combustor components that required frequent cleaning of the test rig. During the program Mars engine first-stage turbine blades were coated and installed for an engine cyclic endurance run with the zirconia, calcium titanate, and calcium silicate coatings. Heavy spalling developed with the calcium silicate system. The zirconia and calcium titanate systems survived the full test duration. It was concluded that these two TBC's showed potential for application in gas turbines

  16. Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants for improved osteointegration.

    Science.gov (United States)

    Carradò, A; Perrin-Schmitt, F; Le, Q V; Giraudel, M; Fischer, C; Koenig, G; Jacomine, L; Behr, L; Chalom, A; Fiette, L; Morlet, A; Pourroy, G

    2017-03-01

    The aim of this study was to improve the strength and quality of the titanium-hydroxyapatite interface in order to prevent long-term failure of the implanted devices originating from coating delamination and to test it in an in-vivo model. Ti disks and dental commercial implants were etched in Kroll solution. Thermochemical treatments of the acid-etched titanium were combined with sol-gel hydroxyapatite (HA) coating processes to obtain a nanoporous hydroxyapatite/sodium titanate bilayer. The sodium titanate layer was created by incorporating sodium ions onto the Ti surface during a NaOH alkaline treatment and stabilized using a heat treatment. HA layer was added by dip-coating in a sol-gel solution. The bioactivity was assessed in vitro with murine MC3T3-E1 and human SaOs-2 cells. Functional and histopathological evaluations of the coated Ti implants were performed at 22, 34 and 60days of implantation in a dog lower mandible model. Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants was sensitive neither to crack propagation nor to layer delamination. The in vitro results on murine MC3T3-E1 and human SaOs-2 cells confirm the advantage of this coating regarding the capacity of cell growth and differentiation. Signs of progressive bone incorporation, such as cancellous bone formed in contact with the implant over the existing compact bone, were notable as early as day 22. Overall, osteoconduction and osteointegration mean scores were higher for test implants compared to the controls at 22 and 34 days. Nanoporous hydroxyapatite/sodium titanate bilayer improves the in-vivo osteoconduction and osteointegration. It prevents the delamination during the screwing and it could increase HA-coated dental implant stability without adhesive failures. The combination of thermochemical treatments with dip coating is a low-cost strategy. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Near-infrared radiation curable multilayer coating systems and methods for applying same

    Science.gov (United States)

    Bowman, Mark P; Verdun, Shelley D; Post, Gordon L

    2015-04-28

    Multilayer coating systems, methods of applying and related substrates are disclosed. The coating system may comprise a first coating comprising a near-IR absorber, and a second coating deposited on a least a portion of the first coating. Methods of applying a multilayer coating composition to a substrate may comprise applying a first coating comprising a near-IR absorber, applying a second coating over at least a portion of the first coating and curing the coating with near infrared radiation.

  18. Printed Barium Strontium Titanate capacitors on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Sette, Daniele [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg); Kovacova, Veronika [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Defay, Emmanuel, E-mail: emmanuel.defay@list.lu [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg)

    2015-08-31

    In this paper, we show that Barium Strontium Titanate (BST) films can be prepared by inkjet printing of sol–gel precursors on platinized silicon substrate. Moreover, a functional variable capacitor working in the GHz range has been made without any lithography or etching steps. Finally, this technology requires 40 times less precursors than the standard sol–gel spin-coating technique. - Highlights: • Inkjet printing of Barium Strontium Titanate films • Deposition on silicon substrate • Inkjet printed silver top electrode • First ever BST films thinner than 1 μm RF functional variable capacitor that has required no lithography.

  19. Electrically conductive, black thermal control coatings for spacecraft applications. III - Plasma-deposited ceramic matrix

    Science.gov (United States)

    Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

    1987-01-01

    Five black, electrically-conductive thermal control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consist of both organic and inorganic systems applied on titanium, aluminum, and glass/epoxy composite surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation, convective and combustive heating, and cryogenic conditions over a temperature range between -196 C and 538 C. Mechanical, physical, thermal, electrical, and thermooptical properties are presented for one of these coatings. This paper describes the preparation, characteristics, and spraying of iron titanate on titanium and aluminum, and presents performance results.

  20. Preparation and characterization of titanate nanotubes/carbon composites

    International Nuclear Information System (INIS)

    Wang Xiaodong; Pan Hui; Xue Xiaoxiao; Qian Junjie; Yu Laigui; Yang Jianjun; Zhang Zhijun

    2011-01-01

    Highlights: → Titanate nanotubes/carbon composites were synthesized from TiO 2 -carbon composites. → The carbon shell of TiO 2 particles obstructed the reaction between TiO 2 and NaOH. → TEM, XRD, and Raman spectra reveal the formation processes of the TNT/CCs. - Abstract: Titanate nanotubes/carbon composites(TNT/CCs) were synthesized by allowing carbon-coated TiO 2 (CCT) powder to react with a dense aqueous solution of NaOH at 120 deg. C for a proper period of time. As-prepared CCT and TNT/CCs were characterized by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectrometry. The processes for formation of titanate nanotubes/carbon composites were discussed. It was found that the TiO 2 particles in TiO 2 -carbon composite were enwrapped by a fine layer of carbon with a thickness of about 4 nm. This carbon layer functioned to inhibit the transformation from anatase TiO 2 to orthorhombic titanate. As a result, the anatase TiO 2 in CCT was incompletely transformed into orthorhombic titanate nanotubes upon 24 h of reaction in the dense and hot NaOH solution. When the carbon layers were gradually peeled off along with the formation of more orthorhombic titanate nanotubes at extended reaction durations (e.g., 72 h), anatase TiO 2 particles in CCT were completely transformed into orthorhombic titanate nanotubes, yielding TNT/CCs whose morphology was highly dependent on the reaction time and temperature.

  1. Fabrication of barium titanate nanoparticles/poly (methylmethacrylate composite films by a combination of deposition process and spin-coating technique

    Directory of Open Access Journals (Sweden)

    Yoshio Kobayashi

    2014-10-01

    Full Text Available The present work proposes a method for fabricating poly(methylmethacrylate (PMMA film containing barium titanate (BT nanoparticles (BT/PMMA film. BT particles with an average size of 77.6 ± 30.5 nm and a crystal size of 28.1 nm were synthesized by adding sodium hydroxide aqueous solution to titanium tetraisopropoxide/acetylacetone/i-propanol solution suspending barium hydroxide. A sodium glass plate, of which surface was modified with polyvinylpyrrolidone, was immersed into water suspending the BT particles, which resulted in deposition of the BT particles on the plate. A BT/PMMA film was fabricated by twice performance of a process composed of spin-coating of N-methyl-2-pyrrolidone (NMP dissolving PMMA on the plate, and then drying the coated plate in the atmosphere at room temperature. Spin-coating of a PMMA/NMP solution with a PMMA concentration of 150 g/L at a rotating speed of 5000 rpm provided fabrication of a BT/PMMA film with a BT volume fraction of 35.5%, a thickness of ca. 300 nm, and a transmittance of ca. 90% in the visible light region.

  2. On reactive suspension plasma spraying of calcium titanate

    OpenAIRE

    Kotlan, J. (Jiří); Pala, Z. (Zdeněk); Mušálek, R. (Radek); Ctibor, P. (Pavel)

    2016-01-01

    This study shows possibility of preparation of calcium titanate powder and coatings by reactive suspension plasma spraying. Suspension of mixture of calcium carbonate (CaCO3) and titanium dioxide (TiO2) powders in ethanol was fed into hybrid plasma torch with a DC-arc stabilized by a water–argon mixture (WSP-H 500). Various feeding distances and angles were used in order to optimize suspension feeding conditions. In the next step, the coatings were deposited on stainless steel substrates and ...

  3. Ceramic protective coatings applied by sol-gel or electrophoresis

    International Nuclear Information System (INIS)

    Stoch, A.

    1993-01-01

    Sol-gel and electrophoresis are the complementary techniques which may be used for obtaining the ceramic coatings. The composition of such a coatings depends on the composition of electrophoresis bath or sol solution. Thermal treatment is used for densifying the coating and promoting the adherence of coating to the substrate. In presented work silica, silica-alumina or alumina coatings are applied by sol-gel dip coating procedure on steel, aluminium or ceramic substrates. Electrophoresis is employed for obtaining zirconia, alumina or hydroxyapatite coatings on stainless steel. (author). 7 refs

  4. Layered titanates with fibrous nanotopographic features as reservoir for bioactive ions to enhance osteogenesis

    Science.gov (United States)

    Song, Xiaoxia; Tang, Wei; Gregurec, Danijela; Yate, Luis; Moya, Sergio Enrique; Wang, Guocheng

    2018-04-01

    In this study, an osteogenic environment was constructed on Ti alloy implants by in-situ formation of nanosized fibrous titanate, Na2Ti6O13, loaded with bioactive ions, i.e. Sr, Mg and Zn, to enhance surface bioactivity. The bioactive ions were loaded by ion exchange with sodium located at inter-layer positions between the TiO6 slabs, and their release was not associated with the degradation of the structural unit of the titanate. In-vitro cell culture experiments using MC3T3-E1 cells proved that both bioactive ions and nanotopographic features are critical in promoting osteogenic differentiation of the cells. It was found that the osteogenic functions of the titanate can be modulated by the type and amount of ions incorporated. This study points out that nanosized fibrous titanate formed on the Ti alloy can be a promising reservoir for bioactive ions. The major advantage of this approach over other alternatives for bioactive ion delivery using degradable bioceramic coatings is its capacity of maintaining the structural integrity of the coating and thus avoiding structural deterioration and potential mechanical failure.

  5. High rate capacity nanocomposite lanthanum oxide coated lithium zinc titanate anode for rechargeable lithium-ion battery

    International Nuclear Information System (INIS)

    Tang, Haoqing; Zan, Lingxing; Zhu, Jiangtao; Ma, Yiheng; Zhao, Naiqin; Tang, Zhiyuan

    2016-01-01

    Lithium zinc titanate (Li_2ZnTi_3O_8) is an important titanium material of promising candidates for anode materials with superior electrochemical performance and thus has attracted extensive attention. Herein, high capacity, stable Li_2ZnTi_3O_8/La_2O_3 nanocomposite for lithium-ion battery anode is prepared by a facile strategy. Compared to unmodified Li_2ZnTi_3O_8, the Li_2ZnTi_3O_8/La_2O_3 electrode display a high specific capacity of 188.6 mAh g"−"1 and remain as high as 147.7 mAh g"−"1 after 100 cycles at 2.0 A g"−"1. Moreover, a reversible capacity of 76.3 mAh g"−"1 can be obtained after 1000 cycles at 2.0 A g"−"1 and the retention is 42.7% for Li_2ZnTi_3O_8/La_2O_3, which is much higher than un-coated Li_2ZnTi_3O_8. The superior lithium storage performances of the Li_2ZnTi_3O_8/La_2O_3 can be ascribed to the stable layer of protection, small particle size and large surface area. Cyclic voltammograms result reveals that the La_2O_3 coating layer reduces the polarization and improves the electrochemical activity of anode. - Highlights: • Nano layer La_2O_3 coated Li_2ZnTi_3O_8 particles have been prepared via a suspension mixing process followed by heat treatment. • Coated Li_2ZnTi_3O_8 has enhanced high rate capability, cyclic stability and long lifespan performance. • Electrochemical properties were tested in a charge/discharge voltage range of 3.0–0.05 V (vs. Li/Li"+).

  6. RF Magnetron Sputtering Coating Of Hydroxyapatite On Alkali Solution Treated Titanate Nanorods

    Directory of Open Access Journals (Sweden)

    Lee K.

    2015-06-01

    Full Text Available Hydroxyapatite (HA is a material with outstanding biocompatibility. It is chemically similar to natural bone tissue, and has therefore been favored for use as a coating material for dental and orthopedic implants. In this study, RF magnetron sputtering was applied for HA coating. And Alkali treatment was performed in a 5 M NaOH solution at 60°C. The coated HA thin film was heat-treated at a range of temperatures from 300 to 600°C. The morphological characterization and crystal structures of the coated specimens were then obtained via FE-SEM, XRD, and FT-IR. The amorphous thin film obtained on hydrothermally treated nanorods transformed into a crystalline thin film after the heat treatment. The change in the phase transformation, with an enhanced crystallinity, showed a reduced wettability. The hydrothermally treated nanorods with an amorphous thin film, on the other hand, showed an outstanding wettability. The HA thin film perpendicularly coated the nanorods in the upper and inner parts via RF magnetron sputtering, and the FT-IR results confirmed that the molecular bonding of the coated film had an HA structure.

  7. Anti-reflection coatings applied by acid leaching process

    Science.gov (United States)

    Pastirik, E.

    1980-01-01

    The Magicote C process developed by S.M. Thompsen was evaluated for use in applying an antireflective coating to the cover plates of solar panels. The process uses a fluosilicic acid solution supersaturated with silica at elevated temperature to selectively attack the surface of soda-lime glass cover plates and alter the physical and chemical composition of a thin layer of glass. The altered glass layer constitutes an antireflective coating. The process produces coatings of excellent optical quality which possess outstanding resistance to soiling and staining. The coatings produced are not resistant to mechanical abrasion and are attacked to some extent by glass cleansers. Control of the filming process was found to be difficult.

  8. Titan!

    Science.gov (United States)

    Matson, Dennis L.

    2010-05-01

    Cassini-Huygens achieved Saturnian orbit on July 1, 2004. The first order of business was the safe delivery of the Huygens atmospheric probe to Titan that took place on January 14, 2005. Huygens descended under parachute obtaining observations all the way down to a safe landing. It revealed Titan for the first time. Stunning are the similarities between Titan and the Earth. Viewing the lakes and seas, the fluvial terrain, the sand dunes and other features through the hazy, nitrogen atmosphere, brings to mind the geological processes that created analogous features on the Earth. On Titan frozen water plays the geological role of rock; liquid methane takes the role of terrestrial water. The atmospheres of both Earth and Titan are predominately nitrogen gas. Titan's atmosphere contains 1.5% methane and no oxygen. The surface pressure on Titan is 1.5 times the Earth's. There are aerosol layers and clouds that come and go. Now, as Saturn proceeds along its solar orbit, the seasons are changing. The effects upon the transport of methane are starting to be seen. A large lake in the South Polar Region seems to be filling more as winter onsets. Will the size and number of the lakes in the South grow during winter? Will the northern lakes and seas diminish or dry up as northern summer progresses? How will the atmospheric circulation change? Much work remains not only for Cassini but also for future missions. Titan has many different environments to explore. These require more capable instruments and in situ probes. This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration.

  9. Coating-substrate-simulations applied to HFQ® forming tools

    Directory of Open Access Journals (Sweden)

    Leopold Jürgen

    2015-01-01

    Full Text Available In this paper a comparative analysis of coating-substrate simulations applied to HFQTM forming tools is presented. When using the solution heat treatment cold die forming and quenching process, known as HFQTM, for forming of hardened aluminium alloy of automotive panel parts, coating-substrate-systems have to satisfy unique requirements. Numerical experiments, based on the Advanced Adaptive FE method, will finally present.

  10. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan. A study in mice

    Directory of Open Access Journals (Sweden)

    Vibenholt Anni

    2010-06-01

    Full Text Available Abstract Background Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181. Methods Time-mated mice (C57BL/6BomTac were exposed by inhalation 1h/day to 42 mg/m3 aerosolized powder (1.7·106 n/cm3; peak-size: 97 nm on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Results Particles consisted of mainly elongated rutile titanium dioxide (TiO2 with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test. Conclusion Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  11. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice.

    Science.gov (United States)

    Hougaard, Karin S; Jackson, Petra; Jensen, Keld A; Sloth, Jens J; Löschner, Katrin; Larsen, Erik H; Birkedal, Renie K; Vibenholt, Anni; Boisen, Anne-Mette Z; Wallin, Håkan; Vogel, Ulla

    2010-06-14

    Engineered nanoparticles are smaller than 100 nm and designed to improve or achieve new physico-chemical properties. Consequently, also toxicological properties may change compared to the parent compound. We examined developmental and neurobehavioral effects following maternal exposure to a nanoparticulate UV-filter (UV-titan L181). Time-mated mice (C57BL/6BomTac) were exposed by inhalation 1h/day to 42 mg/m(3) aerosolized powder (1.7.10(6) n/cm(3); peak-size: 97 nm) on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring neurofunction and fertility. Physicochemical particle properties were determined to provide information on specific exposure and deposition. Particles consisted of mainly elongated rutile titanium dioxide (TiO2) with an average crystallite size of 21 nm, modified with Al, Si and Zr, and coated with polyalcohols. In exposed adult mice, 38 mg Ti/kg was detected in the lungs on day 5 and differential cell counts of bronchoalveolar lavage fluid revealed lung inflammation 5 and 26-27 days following exposure termination, relative to control mice. As young adults, prenatally exposed offspring tended to avoid the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test). Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally exposed offspring displayed moderate neurobehavioral alterations. The results are discussed in the light of the observed particle size distribution in the exposure atmosphere and the potential pathways by which nanoparticles may impart changes in fetal development.

  12. Chemical vapor deposition: A technique for applying protective coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, T.C. Sr.; Bowman, M.G.

    1979-01-01

    Chemical vapor deposition is discussed as a technique for applying coatings for materials protection in energy systems. The fundamentals of the process are emphasized in order to establish a basis for understanding the relative advantages and limitations of the technique. Several examples of the successful application of CVD coating are described. 31 refs., and 18 figs.

  13. Maternal inhalation of surface-coated nanosized titanium dioxide (UV-Titan) in C57BL/6 mice

    DEFF Research Database (Denmark)

    Jackson, Petra; Halappanavar, Sabina; Hougaard, Karin Sorig

    2013-01-01

    We investigated effects of maternal pulmonary exposure to titanium dioxide (UV-Titan) on prenatally exposed offspring. Time-mated mice (C57BL/6BomTac) were inhalation exposed (1 h/day to 42 mg UV-Titan/m(3) aerosolised powder or filtered air) during gestation days (GDs) 8-18. We evaluated DNA...... strand breaks using the comet assay in bronchoalveolar lavage (BAL) cells and livers of the time-mated mice (5 and 26-27 days after inhalation exposure), and in livers of the offspring (post-natal days (PND) 2 and 22). We also analysed hepatic gene expression in newborns using DNA microarrays. UV-Titan...

  14. Annealing effect on corrosion resistance of Bi{sub x}Ti{sub y}O{sub z} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pinzon, M. J.; Alfonsoa, J. E.; Olaya, J. J. [Universidad Nacional de Colombia, Grupo de Ciencia de Materiales y Superficies, Bogota AA 14490 (Colombia); Pineda Vargas, C. A., E-mail: jealfonsoo@unal.edu.co [iThemba LABS, Materials Research Department, PO Box 722, Somerset West 7129 (South Africa)

    2016-11-01

    Bismuth titanate (Bi-xTi{sub y}O{sub z}) has received widespread attention due to the fact that during recent times it has found important applications in strategic research fields such as optics and optoelectronic, and more recently studies have shown how their physicochemical properties may be harnessed in order to be able to use Bi{sub x}Ti{sub y}O{sub z}, as an anti corrosive coating. In this work bismuth titanate (Bi{sub x}Ti{sub y}O{sub z}) coatings were grown on titanium alloy (Ti6A14V) substrates, using RF magnetron sputtering at room temperature. The main objectives of the work were quantify the evolution of crystallographic phase formation, as a function of the annealing temperature, and establish the chemical composition in order to characterize the behaviour of the bismuth titanate coating as a protective coating of the corrosion. The morphology of the coating was observed via scanning electronic microscopy (Sem); the crystalline structure was characterized by X-ray diffraction (XRD) and the chemical composition was analyzed by Rutherford Backscattering Spectrometry (RBS). The corrosion resistance of the coatings was studied by potentiodynamic polarization (Pp) test (Tafel extrapolation). Sem results showed that the surface roughness of the coatings changed when the temperature of annealing increased. Similar change occurred after Pp tests. The XRD analysis revealed a change in the coatings microstructure as a function of the annealing temperature, since they evolved from a completely amorphous phase to a polycrystalline phase. RBS results indicate that coatings growing at high temperature have a complex chemical composition. Finally, the electrochemical analysis showed that the corrosion resistance of the coating is much better in the amorphous phases of bismuth titanate than in the polycrystalline phases. (Author)

  15. Structural and optical investigations of sol–gel derived lithium titanate thin films

    International Nuclear Information System (INIS)

    Łapiński, M.; Kościelska, B.; Sadowski, W.

    2012-01-01

    Highlights: ► Lithium titanate thin films were deposited on glass substrates by sol–gel method. ► After annealing at 550 °C samples had lithium titanate spinel structure. ► Above 80 h of annealing mixture of lithium titanate and titanium oxides was appeared. ► Optical transmittance decreased with increasing of annealing time. - Abstract: In this paper structural and optical studies of lithium titanate (LTO) thin films are presented. Nanocrystalline thin films with 800 nm thickness were prepared by sol–gel method. To examine the influence of the annealing time on as-prepared films crystallization, the coatings were heated at 550 °C for 10, 20 and 80 h. Structure of manufactured thin films was investigated using X-ray diffraction (XRD). The most visible lithium titanate phase was obtained after 20 h annealing. Increasing of annealing time over 20 h revealed appearance of titanium oxides phase. On the basis of transmission characteristic optical properties were calculated. It was found that transmission through the thin films was reduced and position of the fundamental absorption edge was shifted toward a longer wavelength with increasing of annealing time. The optical band gap was calculated for direct allowed and indirect allowed transitions from optical absorption spectra.

  16. 钛酸酯偶联剂对包硅铝钛白粉表面的有机改性%Surface Organic Modification of SiO2 & Al2O3 Coated TiO2 Particles with Titanate Coupling Reagent

    Institute of Scientific and Technical Information of China (English)

    林玉兰; 王亭杰; 覃操; 金涌

    2001-01-01

    The surface organic modification of TiO2 particles with titanate coupling reagent,which was pre-coated with double layers of SiO2 and Al2O3,was studied.Experiments showed that the modified particles exhibited hydrophobic characteristics.The modification state of the particle surface was characterized by IR spectroscopic measurement,pyrolytic gas chromatography,thermogravimetric analysis and X-ray photoelectron spectra.The titanate coupling reagent binding with the hydroxyl on the particle surface was analyzed.The surface characteristics of pre-modification and post-modification particles were compared.

  17. Application of TITAN for Simulation of Particle Streaming in a Duct

    Directory of Open Access Journals (Sweden)

    Royston Katherine

    2016-01-01

    Full Text Available The TITAN hybrid deterministic transport code is applied to the simulation of particle streaming in a nuclear power plant duct. A simple model is used consisting of a concrete duct emerging from the pressure vessel with an isotropic surface source with a U-235 fission spectrum located at the pressure vessel end. Multiple methods of simulating the duct using the TITAN code are considered to demonstrate the flexibility of the code and the advantages of TITAN's algorithms. These methods include a discrete ordinates (SN calculation, a characteristics method calculation, and the use of a fictitious quadrature set with simplified ray-tracing. The TITAN code's results are compared with MCNP5 solutions. While all TITAN solutions are obtained in a shorter computation time than the MCNP5 solution, the TITAN solution with the fictitious quadrature set shows the largest speedup.

  18. High rate capacity nanocomposite lanthanum oxide coated lithium zinc titanate anode for rechargeable lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Haoqing, E-mail: tanghaoqing@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Department of Applied Chemistry, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zan, Lingxing [Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn 53117 (Germany); Zhu, Jiangtao; Ma, Yiheng [Department of Applied Chemistry, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zhao, Naiqin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tang, Zhiyuan, E-mail: zytang46@163.com [Department of Applied Chemistry, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2016-05-15

    Lithium zinc titanate (Li{sub 2}ZnTi{sub 3}O{sub 8}) is an important titanium material of promising candidates for anode materials with superior electrochemical performance and thus has attracted extensive attention. Herein, high capacity, stable Li{sub 2}ZnTi{sub 3}O{sub 8}/La{sub 2}O{sub 3} nanocomposite for lithium-ion battery anode is prepared by a facile strategy. Compared to unmodified Li{sub 2}ZnTi{sub 3}O{sub 8}, the Li{sub 2}ZnTi{sub 3}O{sub 8}/La{sub 2}O{sub 3} electrode display a high specific capacity of 188.6 mAh g{sup −1} and remain as high as 147.7 mAh g{sup −1} after 100 cycles at 2.0 A g{sup −1}. Moreover, a reversible capacity of 76.3 mAh g{sup −1} can be obtained after 1000 cycles at 2.0 A g{sup −1} and the retention is 42.7% for Li{sub 2}ZnTi{sub 3}O{sub 8}/La{sub 2}O{sub 3}, which is much higher than un-coated Li{sub 2}ZnTi{sub 3}O{sub 8}. The superior lithium storage performances of the Li{sub 2}ZnTi{sub 3}O{sub 8}/La{sub 2}O{sub 3} can be ascribed to the stable layer of protection, small particle size and large surface area. Cyclic voltammograms result reveals that the La{sub 2}O{sub 3} coating layer reduces the polarization and improves the electrochemical activity of anode. - Highlights: • Nano layer La{sub 2}O{sub 3} coated Li{sub 2}ZnTi{sub 3}O{sub 8} particles have been prepared via a suspension mixing process followed by heat treatment. • Coated Li{sub 2}ZnTi{sub 3}O{sub 8} has enhanced high rate capability, cyclic stability and long lifespan performance. • Electrochemical properties were tested in a charge/discharge voltage range of 3.0–0.05 V (vs. Li/Li{sup +}).

  19. Drag resistance measurements for newly applied antifouling coatings and welding seams on ship hull surface

    DEFF Research Database (Denmark)

    Wang, Xueting; Olsen, S. M.; Andres, E.

    Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared in their......Drag resistances of newly applied antifouling coatings and welding seams on ship hull surface have been investigated using a pilot-scale rotary setup. Both conventional biocide-based antifouling (AF) coatings and silicone-based fouling release (FR) coatings have been studied and compared...

  20. Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry

    Directory of Open Access Journals (Sweden)

    Mozafari M

    2013-04-01

    Full Text Available Masoud Mozafari,1,2 Erfan Salahinejad,1,3 Vahid Shabafrooz,1 Mostafa Yazdimamaghani,1 Daryoosh Vashaee,4 Lobat Tayebi1,5 1Helmerich Advanced Technology Research Center, School of Materials Science and Engineering, Oklahoma State University, Tulsa, OK, USA; 2Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence, Amirkabir University of Technology, Tehran, Iran; 3Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, Iran; 4Helmerich Advanced Technology Research Center, School of Electrical and Computer Engineering, Oklahoma State University, Tulsa, OK, USA; 5School of Chemical Engineering, Oklahoma State University, Tulsa, OK, USA Abstract: Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. Keywords: bioactive glass, zirconium titanate, spin-coating, microstructural properties, bone/dental applications, tissue engineering

  1. The mechanochemical stability of hydrogen titanate nanostructures

    International Nuclear Information System (INIS)

    Plodinec, M.; Friscic, I.; Ivekovic, D.; Tomasic, N.; Su, D.S.; Zhang, J.; Gajovic, A.

    2010-01-01

    The structural stability of some nanostructured titanates was investigated in terms of their subsequent processing and possible applications. With the aim to investigate their mechanochemical stability, we applied high-energy ball milling and studied the resulting induced phase transitions. Hydrogen titanates with two different morphologies, microcrystals and nanotubes, were taken into consideration. The phase-transition sequence was studied by Raman spectroscopy and X-ray powder diffraction, while the morphology and crystal structure, on the nanoscale, were analyzed by high-resolution transmission electron microscopy. During the mechanochemical treatment of both morphologies, the phase transitions from hydrogen titanate to TiO 2 anatase and subsequently to TiO 2 rutile were observed. In the case of hydrogen trititanate crystals, the phase transition to anatase starts after a longer milling time than in the case of the titanate nanotubes, which is explained by the larger particle size of the crystalline powder. However, the phase transition from anatase to rutile occurred more quickly in the crystalline powder than in the case of the nanotubes.

  2. Current—voltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites

    International Nuclear Information System (INIS)

    De-An, Pan; Shen-Gen, Zhang; Jian-Jun, Tian; Li-Jie, Qiao; Jun-Sai, Sun; Volinsky, Alex A.

    2010-01-01

    Current–voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current–voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current–voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  3. Application of Epoxy Based Coating Instacote on Waste Tank Tops

    International Nuclear Information System (INIS)

    Pike, J.A.

    1998-01-01

    This evaluation examines the compatibility of coating Instacote with existing High-Level Waste facilities and safety practices. No significant incompatibilities are identified. The following actions need to be completed as indicated when applying Instacote on waste tank tops:(1) Prior to application in ITP facilities, the final product should be tested for chemical resistance to sodium tetraphenylborate solutions or sodium titanate slurries.(2) Any waste contaminated with Part A or B that can not be removed by the vendor such as for radiological contamination, HLW must hold the waste until HLW completes a formal assessment of the waste, disposal criteria, and impact.(3) Prior to the start of any application of the coating, each riser needs to be evaluated for masking and masking applied if needed.(4) At the conclusion of an application actual total weight of material applied to a waste tank needs to documented and sent to the tank top loading files for reference purposes.(5) Verify that the final product contains less than 250 ppm chloride

  4. Titan after Cassini Huygens

    Science.gov (United States)

    Beauchamp, P. M.; Lunine, J.; Lebreton, J.; Coustenis, A.; Matson, D.; Reh, K.; Erd, C.

    2008-12-01

    architecture inherently provides the optimal balance between science, risk, and cost using three guiding principles: Achieve science well beyond the high bar set by Cassini Huygens. The TSSM orbiter, lander, and balloon have been configured with instruments and operational concept that go well beyond Cassini-Huygens capabilities, thus ensuring dramatic remote observation and in situ science discoveries. Build upon successful design and operational experience and lessons learned. ESA has successful experience in designing and landing probes on Titan (Huygens), as does NASA in implementing an orbiter at Saturn (Cassini). Long life design rules and extensive operational experience in the Saturn system have been applied to form the TSSM concept. Lessons learned from Galileo, Cassini, New Horizons, and MRO have been applied to reduce risk and lower cost. Development by ESA of the montgolfiere combines prior experience with Earth and planetary balloon systems to enable innovative science and unprecedented mobility for surface exploration. Strong international partnership. TSSM represents a collaborative effort between NASA and ESA that is structured to provide the best possible mission at a reasonable cost to NASA and to ESA. This NASA-ESA partnership leverages resources to maximize science return, distribute risk, and ensure technical readiness.

  5. Tritium breeding experiments with lithium titanate in thermal-type mockups

    International Nuclear Information System (INIS)

    Klix, Axel; Takahashi, Akito; Ochiai, Kentaro; Nishitani, Takeo

    2004-01-01

    Lithium titanate, an advanced tritium breeding material, is currently investigated in integral mock-up experiments at FNS. A method was developed which allows to measure low tritium concentrations directly in this material. The local tritium production rate was obtained by small lithium titanate pellet detectors inserted into the breeding layers which are dissolved after irradiation of the assemblies, and the accumulated tritium was counted by liquid scintillation techniques. The measurement method was applied in mock0-up experiments with candidate materials for the future DEMO reactor breeding blanket. Experimental assemblies consisted of sheets of low activation ferritic steel F82H, lithium titanate, and berylium. Tritium production rate profiles were obtained and compared with results from calculations with the Monte Carlo neutron transport code MCNP-4C. In case of the mock-ups with 95% enriched lithium titanate, the C/E ratios were within the error estimate while larger discrepancies were observed in case of 40% enriched lithium titanate. (author)

  6. Titan's Radioactive Haze : Production and Fate of Radiocarbon On Titan

    Science.gov (United States)

    Lorenz, R. D.; Jull, A. J. T.; Swindle, T. D.; Lunine, J. I.

    Just as cosmic rays interact with nitrogen atoms in the atmosphere of Earth to gener- ate radiocarbon (14C), the same process should occur in Titan`s nitrogen-rich atmo- sphere. Titan`s atmosphere is thick enough that cosmic ray flux, rather than nitrogen column depth, limits the production of 14 C. Absence of a strong magnetic field and the increased distance from the sun suggest production rates of 9 atom/cm2/s, approx- imately 4 times higher than Earth. On Earth the carbon is rapidly oxidised into CO2. The fate and detectability of 14C on Titan depends on the chemical species into which it is incorporated in Titan's reducing atmosphere : as methane it would be hopelessly diluted even in only the atmosphere (ignoring the other, much more massive carbon reservoirs likely to be present on Titan, like hydrocarbon lakes.) However, in the more likely case that the 14C attaches to the haze that rains out onto the surface (as tholin, HCN or acetylene and their polymers - a much smaller carbon reservoir) , haze in the atmosphere or recently deposited on the surface would therefore be quite intrinsically radioactive. Such activity may modify the haze electrical charging and hence its coag- ulation. Measurements with compact instrumentation on future in-situ missions could place useful constraints on the mass deposition rates of photochemical material on the surface and identify locations where surface deposits of such material are `freshest`.

  7. Titan Casts Revealing Shadow

    Science.gov (United States)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  8. Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

    Science.gov (United States)

    Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

    2014-07-01

    A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

  9. Fracture and flaking off behavior of coated layer of DyBCO coated conductor under applied tensile strain

    International Nuclear Information System (INIS)

    Arai, T.; Shin, J.K.; Matsubayashi, H.; Ochiai, S.; Okuda, H.; Osamura, K.; Prusseit, W.

    2009-01-01

    The tensile behavior of the DyBa 2 Cu 3 O 7-δ (DyBCO) coated conductor with MgO buffer layer deposited on the Hastelloy C-276 substrate by inclined substrate deposition (ISD) was studied. The tensile stress-strain curve showed a flat region, characterized by the discontinuous yielding of the substrate due to the Lueders band extension from the gripped portions of the sample. In the area where the Lueders band had passed, the coating layer showed severe multiple transverse cracking due to the localized plastic deformation of the substrate. The flaking off of the coating layers took place at high applied strain, due to the buckling fracture of the coated layers in the sample width direction, accompanied by the interfacial debonding.

  10. Synthesis of Barium Titanate (BT) Nano Particles via Hydrothermal Route for the Production of BT-Polymer Nanocomposite

    Science.gov (United States)

    Habib, A.; Haubner, R.; Jakopic, G.; Stelzer, N.

    2007-08-01

    Barium titanate (high-k dielectric material) nano-powders (approx. 30 nm to 60 nm) were synthesised using hydrothermal route under moderate conditions. Effect of temperature and time was studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction techniques. Obtained barium titanate nano-powders were dispersed in thermoplastic polymethyl methacrylate (PMMA) to get homogeneous dispersions. Thin layers were obtained using these dispersions to achieve BaTiO3 endorsed polymer layers by dip-coating for improved polymer insulators on various substrates e.g., glass, and Au sputtered silicon wafers. SEM and focused ion beam (FIB) techniques were used to study the dispersion of barium titanate nano-particles in PMMA. The layers obtained showed homogenous distribution of BaTiO3 nano particles with no agglomeration.

  11. Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry

    Science.gov (United States)

    Mozafari, Masoud; Salahinejad, Erfan; Shabafrooz, Vahid; Yazdimamaghani, Mostafa; Vashaee, Daryoosh; Tayebi, Lobat

    2013-01-01

    Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. PMID:23641155

  12. Positively charged microporous ceramic membrane for the removal of Titan Yellow through electrostatic adsorption.

    Science.gov (United States)

    Cheng, Xiuting; Li, Na; Zhu, Mengfu; Zhang, Lili; Deng, Yu; Deng, Cheng

    2016-06-01

    To develop a depth filter based on the electrostatic adsorption principle, positively charged microporous ceramic membrane was prepared from a diatomaceous earth ceramic membrane. The internal surface of the highly porous ceramic membrane was coated with uniformly distributed electropositive nano-Y2O3 coating. The dye removal performance was evaluated through pressurized filtration tests using Titan Yellow aqueous solution. It showed that positively charged microporous ceramic membrane exhibited a flow rate of 421L/(m(2)·hr) under the trans-membrane pressure of 0.03bar. Moreover it could effectively remove Titan Yellow with feed concentration of 10mg/L between pH3 to 8. The removal rate increased with the enhancement of the surface charge properties with a maximum rejection of 99.6%. This study provides a new and feasible method of removing organic dyes in wastewater. It is convinced that there will be a broad market for the application of charged ceramic membrane in the field of dye removal or recovery from industry wastewater. Copyright © 2016. Published by Elsevier B.V.

  13. Titan's Surface Composition from Cassini VIMS Solar Occultation Observations

    Science.gov (United States)

    McCord, Thomas; Hayne, Paul; Sotin, Christophe

    2013-04-01

    Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is

  14. Titan Aerial Daughtercraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Saturn's giant moon Titan has become one of the most fascinating bodies in the Solar System. Titan is the richest laboratory in the solar system for studying...

  15. Effects of prenatal exposure to surface-coated nanosized titanium dioxide (UV-Titan). A study in mice

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Jackson, Petra; Jensen, Keld A.

    2010-01-01

    to a nanoparticulate UV-filter (UV-titan L181). Methods: Time-mated mice (C57BL/6BomTac) were exposed by inhalation 1h/day to 42 mg/m(3) aerosolized powder (1.7.10(6) n/cm(3); peak-size: 97 nm) on gestation days 8-18. Endpoints included: maternal lung inflammation; gestational and litter parameters; offspring...... the central zone of the open field and exposed female offspring displayed enhanced prepulse inhibition. Cognitive function was unaffected (Morris water maze test). Conclusion: Inhalation exposure to nano-sized UV Titan dusts induced long term lung inflammation in time-mated adult female mice. Gestationally...

  16. Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

    Science.gov (United States)

    Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

    2002-01-01

    The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

  17. A photoacoustic technique applied to detection of ethylene emissions in edible coated passion fruit

    International Nuclear Information System (INIS)

    Alves, G V L; Santos, W C dos; Vargas, H; Silva, M G da; Waldman, W R; Oliveira, J G

    2010-01-01

    Photoacoustic spectroscopy was applied to study the physiological behavior of passion fruit when coated with edible films. The results have shown a reduction of the ethylene emission rate. Weight loss monitoring has not shown any significant differences between the coated and uncoated passion fruit. On the other hand, slower color changes of coated samples suggest a slowdown of the ripening process in coated passion fruit.

  18. Fabrication of crystal-oriented barium-bismuth titanate ceramics in high magnetic field and subsequent reaction sintering

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Tomita, Yusuke; Furushima, Ryoichi; Uematsu, Keizo; Shimizu, Hiroyuki; Doshida, Yutaka

    2009-01-01

    High magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 μ m were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a- and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100 deg. C.

  19. Electromagnetic properties of carbon black and barium titanate composite materials

    International Nuclear Information System (INIS)

    Wang Guiqin; Chen Xiaodong; Duan Yuping; Liu Shunhua

    2008-01-01

    Nanocrystalline carbon black/barium titanate compound particle (CP) was synthesized by sol-gel method. The phase structure and morphology of compound particle were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectrum measurements, the electroconductivity was test by trielectrode arrangement and the precursor powder was followed by differential scanning calorimetric measurements (DSC) and thermal gravimetric analysis (TGA). In addition, the complex relative permittivity and permeability of compound particle were investigated by reflection method. The compound particle/epoxide resin composite (CP/EP) with different contents of CP were measured. The results show barium titanate crystal is tetragonal phase and its grain is oval shape with 80-100 nm which was coated by carbon black film. As electromagnetic (EM) complex permittivity, permeability and reflection loss (RL) shown that the compound particle is mainly a kind of electric and dielectric lossy materials and exhibits excellent microwave absorption performance in the X- and Ku-bands

  20. INFLUENCE OF THE THICKNESS OF Ni-P COATING APPLIED ON 7075 ALUMINUM ALLOY ON ITS HARDNESS

    Directory of Open Access Journals (Sweden)

    Kazimierz Czapczyk

    2016-12-01

    Full Text Available The paper presents the results of hardness tests of aluminum alloy AW-7075 (for plastic processing and Ni-P chemical coatings (nickel-phosphorus which had been applied by the no-current method. Coatings of various thickness have been made and their influence on the increase of the top layer hardness has been determined, as well as the increase of the hardness of the coating and substrate system after puncturing the coating with an indenter. The purpose of the investigation was to determine the possibility of applying the Ni-P coating for selected technical applications, among others, by the selection of its optimum thickness on the hard aluminum alloy and by the determination of the deformation resistance of the top layer if the given coating.

  1. Novel surface coating strategies for better battery materials

    CSIR Research Space (South Africa)

    Wen, L

    2018-03-01

    Full Text Available . Surface-coated cathodes have been demonstrated to be effective in blocking these surface processes and enhancing the electrochemical performance of the materials. For example, the electron-insulating but ion-conducting lithium carbonate (Li2CO3) has been... noticed that most LIB electrode materials have very poor electrical conductivity (e.g. lithium iron phosphate and lithium titanate are almost insulators).22,23 In this regard, surface coating of the electrode active materials with a conductive layer...

  2. The TITAN reversed-field-pinch fusion reactor study

    International Nuclear Information System (INIS)

    1990-01-01

    This report discusses the following topics: overview of titan-2 design; titan-2 fusion-power-core engineering; titan-2 divertor engineering; titan-2 tritium systems; titan-2 safety design and radioactive-waste disposal; and titan-2 maintenance procedures

  3. The TITAN reversed-field-pinch fusion reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This report discusses the following topics: overview of titan-2 design; titan-2 fusion-power-core engineering; titan-2 divertor engineering; titan-2 tritium systems; titan-2 safety design and radioactive-waste disposal; and titan-2 maintenance procedures.

  4. Titan's organic chemistry

    Science.gov (United States)

    Sagan, C.; Thompson, W. R.; Khare, B. N.

    1985-01-01

    Voyager discovered nine simple organic molecules in the atmosphere of Titan. Complex organic solids, called tholins, produced by irradiation of the simulated Titanian atmosphere, are consistent with measured properties of Titan from ultraviolet to microwave frequencies and are the likely main constituents of the observed red aerosols. The tholins contain many of the organic building blocks central to life on earth. At least 100-m, and possibly kms thicknesses of complex organics have been produced on Titan during the age of the solar system, and may exist today as submarine deposits beneath an extensive ocean of simple hydrocarbons.

  5. Epoxy-based broadband antireflection coating for millimeter-wave optics.

    Science.gov (United States)

    Rosen, Darin; Suzuki, Aritoki; Keating, Brian; Krantz, William; Lee, Adrian T; Quealy, Erin; Richards, Paul L; Siritanasak, Praween; Walker, William

    2013-11-20

    We have developed epoxy-based, broadband antireflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 K, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.

  6. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance

    International Nuclear Information System (INIS)

    Ogawa, Makoto; Morita, Masashi; Igarashi, Shota; Sato, Soh

    2013-01-01

    A layered titanate, potassium lithium titanate, with the size range from 0.1 to 30 µm was prepared to show the effects of the particle size on the materials performance. The potassium lithium titanate was prepared by solid-state reaction as reported previously, where the reaction temperature was varied. The reported temperature for the titanate preparation was higher than 800 °C, though 600 °C is good enough to obtain single-phase potassium lithium titanate. The lower temperature synthesis is cost effective and the product exhibit better performance as photocatalysts due to surface reactivity. - Graphical abstract: Finite particle of a layered titanate, potassium lithium titanate, was prepared by solid-state reaction at lower temperature to show modified materials performance. Display Omitted - Highlights: • Potassium lithium titanate was prepared by solid-state reaction. • Lower temperature reaction resulted in smaller sized particles of titanate. • 600 °C was good enough to obtain single phased potassium lithium titanate. • The product exhibited better performance as photocatalyst

  7. The TITAN reversed-field-pinch fusion reactor study

    International Nuclear Information System (INIS)

    1990-01-01

    This report discusses research on the titan-1 fusion power core. The major topics covered are: titan-1 fusion-power-core engineering; titan-1 divertor engineering; titan-1 tritium systems; titan-1 safety design and radioactive-waste disposal; and titan-1 maintenance procedures

  8. The TITAN reversed-field-pinch fusion reactor study

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This report discusses research on the titan-1 fusion power core. The major topics covered are: titan-1 fusion-power-core engineering; titan-1 divertor engineering; titan-1 tritium systems; titan-1 safety design and radioactive-waste disposal; and titan-1 maintenance procedures.

  9. Mapping of strain mechanisms in barium titanate by three-dimensional X-ray diffraction

    DEFF Research Database (Denmark)

    Majkut, Marta

    This thesis presents an in-situ three-dimensional study of the grain-scale response of a prototypical piezoelectric ceramic, barium titanate (BT), to an exernally applied electric field. Piezoceramics take advantage of the coupling of electrical and mechanical energies for use in sensors and actu......This thesis presents an in-situ three-dimensional study of the grain-scale response of a prototypical piezoelectric ceramic, barium titanate (BT), to an exernally applied electric field. Piezoceramics take advantage of the coupling of electrical and mechanical energies for use in sensors...

  10. Titan's Methane Cycle is Closed

    Science.gov (United States)

    Hofgartner, J. D.; Lunine, J. I.

    2013-12-01

    Doppler tracking of the Cassini spacecraft determined a polar moment of inertia for Titan of 0.34 (Iess et al., 2010, Science, 327, 1367). Assuming hydrostatic equilibrium, one interpretation is that Titan's silicate core is partially hydrated (Castillo-Rogez and Lunine, 2010, Geophys. Res. Lett., 37, L20205). These authors point out that for the core to have avoided complete thermal dehydration to the present day, at least 30% of the potassium content of Titan must have leached into an overlying water ocean by the end of the core overturn. We calculate that for probable ammonia compositions of Titan's ocean (compositions with greater than 1% ammonia by weight), that this amount of potassium leaching is achievable via the substitution of ammonium for potassium during the hydration epoch. Formation of a hydrous core early in Titan's history by serpentinization results in the loss of one hydrogen molecule for every hydrating water molecule. We calculate that complete serpentinization of Titan's core corresponds to the release of more than enough hydrogen to reconstitute all of the methane atoms photolyzed throughout Titan's history. Insertion of molecular hydrogen by double occupancy into crustal clathrates provides a storage medium and an opportunity for ethane to be converted back to methane slowly over time--potentially completing a cycle that extends the lifetime of methane in Titan's surface atmosphere system by factors of several to an order of magnitude over the photochemically-calculated lifetime.

  11. Chemistry and evolution of Titan's atmosphere

    International Nuclear Information System (INIS)

    Strobel, D.F.

    1982-01-01

    The chemistry and evolution of Titan's atmosphere is reviewed in the light of the scientific findings from the Voyager mission. It is argued that the present N 2 atmosphere may be Titan's initial atmosphere rather than photochemically derived from an original NH 3 atmosphere. The escape rate of hydrogen from Titan is controlled by photochemical production from hydrocarbons. CH 4 is irreversibly converted to less hydrogen rich hydrocarbons, which over geologic time accumulate on the surface to a layer thickness of approximately 0.5 km. Magnetospheric electrons interacting with Titan's exosphere may dissociate enough N 2 into hot, escaping N atoms to remove approximately 0.2 of Titan's present atmosphere over geologic time. The energy dissipation of magnetospheric electrons exceeds solar e.u.v. energy deposition in Titan's atmosphere by an order of magnitude and is the principal driver of nitrogen photochemistry. The environmental conditions in Titan's upper atmosphere are favorable to building up complex molecules, particularly in the north polar cap region. (author)

  12. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  13. Interaction of Titan's atmosphere with Saturn's magnetosphere

    International Nuclear Information System (INIS)

    Hartle, R.E.

    1985-01-01

    The Voyager 1 measurements made during the Titan flyby reveal that Saturn's rotating magnetospheric plasma interacts directly with Titan's neutral atmosphere and ionosphere. This results from the lack of an intrinsic magnetic field at Titan. The interaction induces a magnetosphere which deflects the flowing plasma around Titan and forms a plasma wake downstream. Within the tail of the induced magnetosphere, ions of ionospheric origin flow away from Titan. Just outside Titan's magnetosphere, a substantial ion-exosphere forms from an extensive hydrogen-nitrogen exosphere. The exospheric ions are picked up and carried downstream into the wake by the plasma flowing around Titan. Mass loading produced by the addition of exospheric ions slows the wake plasma down considerably in the vicinity of the magnetopause. 36 references

  14. Characterization of barium titanate powder doped with sodium and potassium ions by using Rietveld refining

    International Nuclear Information System (INIS)

    Andrade, M.C.; Assis, J.T.; Pereira, F.R.

    2009-01-01

    A solid-reaction synthesis of doped barium titanate was done by employing barium carbonates, sodium, potassium and titanium oxides with classic procedures. Rietveld refining of X ray diffraction data of perovskite samples with tetragonal symmetry was applying and show good agreement. Besides, the treatment performed from 600 deg C produces nanocrystals of barium titanate with average size of 33 nm. The presence of endothermic peaks related to BaTiO 3 formation at relatively low temperatures was determined by thermal analysis. A pseudo-Voigt Thompson-Cox-Hastings function was used to fit the standard samples of barium titanate. The Rietveld method has showed be efficient to detect the influences of temperature and doping on barium titanate microstructures. (author)

  15. A FAMILY OF PEROXO-TITANATE MATERIALS TAILORED FOR OPTIMAL STRONTIUM ANDACTINIDE SORPTION

    International Nuclear Information System (INIS)

    Hobbs, D

    2006-01-01

    Achieving global optimization of inorganic sorbent efficacy, as well as tailoring sorbent specificity for target sorbates would facilitate increased wide-spread use of these materials in applications such as producing potable water or nuclear waste treatment. Sodium titanates have long been known as sorbents for radionuclides; 90 Sr and transuranic elements in particular. We have developed a related class of materials, which we refer to as peroxo-titanates: these are sodium titanates or hydrous titanates synthesized in the presence of or treated post-synthesis with hydrogen peroxide. Peroxo-titanates show remarkable and universal improved sorption behavior with respect to separation of actinides and strontium from Savannah River Site (SRS) nuclear waste simulants. Enhancement in sorption kinetics can potentially result in as much as an order of magnitude increase in batch processing throughput. Peroxo-titanates have been produced by three different synthetic routes: post-synthesis peroxide-treatment of a commercially produced monosodium titanate, an aqueous-peroxide synthetic route, and an isopropanol-peroxide synthetic route. The peroxo-titanate materials are characteristically yellow to orange, indicating the presence of protonated or hydrated Ti-peroxo species; and the chemical formula can be generally written as H v Na w Ti 2 O 5 -(xH 2 O)[yH z O 2 ] where (v+w) = 2, z = 0-2, and total volatile species accounts for 25-50 wt % of the solid. Further enhancement of sorption performance is achieved by processing, storing and utilizing the peroxo-titanate as an aqueous slurry rather than a dry powder, and post-synthesis acidification. All three synthesis modifications; addition of hydrogen peroxide, use of a slurry form and acidification can be applied more broadly to the optimization of other metal oxide sorbents and other ion separations processes

  16. Titanic: A Statistical Exploration.

    Science.gov (United States)

    Takis, Sandra L.

    1999-01-01

    Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)

  17. The age of Titan's surface

    Science.gov (United States)

    Neish, C. D.; Lorenz, R. D.

    2010-04-01

    High-resolution images of the surface of Titan taken by the Cassini spacecraft reveal a world with an extreme paucity of impact craters. Planetary surfaces are commonly dated by dividing the number of impact craters by the estimated impactor flux, but this approach has been confounded at Titan by several difficulties. First, high-resolution imaging of the surface of Titan is far from complete (in the near-infrared as well as radar). As of December 2007, Cassini RADAR images covered only 22% of its surface. However, we can use Monte-Carlo models to explore how many craters of a given size (with large or very large craters being of particular interest) may be present in the unobserved areas. Second, literature descriptions of the crater formation rate (e.g. Korycansky and Zahnle 2005 and Artemieva and Lunine 2005) are apparently not in agreement. We discuss possible resolutions. Third, since surface modification processes are ongoing, the actual number of craters on Titan's surface remains uncertain, as craters may be eroded beyond recognition, or obscured by lakes or sand seas. In this connection, we use the Earth as an analogue. The Earth is in many ways the most "Titan-like" world in the solar system, with extensive modification by erosion, burial, tectonism, and volcanism. We compare the observed number of terrestrial craters to the expected terrestrial impactor flux to determine the crater reduction factor for a world similar to Titan. From this information, we can back out the actual number of craters on Titan's surface and estimate its crater retention age. An accurate age estimate will be critical for constraining models of Titan's formation and evolution.

  18. A Direct Simulation Monte Carlo Model Of Thermal Escape From Titan

    Science.gov (United States)

    Johnson, Robert E.; Tucker, O. J.

    2008-09-01

    Recent analysis of density profiles vs. altitude from the Ion Neutral Mass Spectrometer (INMS) on Cassini (Waite et al. 2005) suggest Titan could have loss a significant amount of atmosphere in 4 Gyr at present escape rates (e.g., Johnson 2008). Strobel 2008 applied a slow hydrodynamic escape model to Titan's atmosphere using solar heating below the exobase to drive upward thermal conduction and power escape. However, near the exobase continuum models become problematic as a result of the increasing rarefaction in the atmosphere. The microscopic nature of DSMC is directly suitable to model atmosphere flow in nominal exobase region (e.g., Michael et. al. 2005). Our Preliminary DSMC models have shown no evidence for slow hydrodynamic escape of N2 and CH4 from Titan's atmosphere using boundary conditions normalized to the atmospheric properties in Strobel (2008). In this paper we use a 1D radial Direct Simulation Monte Carlo (DSMC) model of heating in Titan's upper atmosphere to estimate the escape rate as a function of the Jean's parameter. In this way we can test under what conditions the suggested deviations from Jeans escape would occur. In addition, we will be able to extract the necessary energy deposition to power the heavy molecule loss rates suggested in recent models (Strobel 2008; Yelle et. al. 2008). Michael, M. Johnson, R.E. 2005 Energy Deposition of pickup ions and heating of Titan's atmosphere. Planat. Sp. Sci. 53, 1510-1514 Johnson, R.E., "Sputtering and Heating of Titan's Upper Atmosphere", Proc Royal Soc. (London) (2008) Strobel, D.F. 2008 Titan's hydrodynamically escaping atmosphere. Icarus 193, 588-594 Yelle, R.V., J. Cui and I. C.F. Muller-Wodarg 2008 Methane Escape from Titan's Atmosphere. J. Geophys. Res in press Waite, J.H., Jr., Niemann, H.B., Yelle, R.V. et al. 2005 Ion Neutral Mass Spectrometer Results from the First Flyby of Titan. Science 308, 982-986

  19. The Titan Sky Simulator ™ - Testing Prototype Balloons in Conditions Approximating those in Titan's Atmosphere

    Science.gov (United States)

    Nott, Julian

    This paper will describe practical work flying prototype balloons in the "The Titan Sky Simulator TM " in conditions approximating those found in Titan's atmosphere. Saturn's moon, Titan, is attracting intense scientific interest. This has led to wide interest in exploring it with Aerobots, balloons or airships. Their function would be similar to the Rovers exploring Mars, but instead of moving laboriously across the rough terrain on wheels, they would float freely from location to location. To design any balloon or airship it is essential to know the temperature of the lifting gas as this influences the volume of the gas, which in turn influences the lift. To determine this temperature it is necessary to know how heat is transferred between the craft and its surroundings. Heat transfer for existing balloons is well understood. However, Titan conditions are utterly different from those in which balloons have ever been flown, so heat transfer rates cannot currently be calculated. In particular, thermal radiation accounts for most heat transfer for existing balloons but over Titan heat transfer will be dominated by convection. To be able to make these fundamental calculations, it is necessary to get fundamental experimental data. This is being obtained by flying balloons in a Simulator filled with nitrogen gas at very low temperature, about 95° K / minus 180° C, typical of Titan's temperatures. Because the gas in the Simulator is so cold, operating at atmospheric pressure the density is close to that of Titan's atmosphere. "The Titan Sky Simulator TM " has an open interior approximately 4.5 meter tall and 2.5 meters square. It has already been operated at 95° K/-180° C. By the time of the Conference it is fully expected to have data to present from actual balloons flying at this temperature. Perhaps the most important purpose of this testing is to validate numerical [computational fluid dynamics] models being developed by Tim Colonius of Caltech. These numerical

  20. The atmospheric temperature structure of Titan

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, J. B.; Courtin, Regis; Lunine, Jonathan I.

    1992-01-01

    The contribution of various factors to the thermal structure of Titan's past and present atmosphere are discussed. A one dimensional model of Titan's thermal structure is summarized. The greenhouse effect of Titan's atmosphere, caused primarily by pressure induced opacity of N2, CH4, and H2, is discussed together with the antigreenhouse effect dominated by the haze which absorbs incident sunlight. The implications for the atmosphere of the presence of an ocean on Titan are also discussed.

  1. Advanced Antireflection Coatings for High-Performance Solar Energy Applications

    Science.gov (United States)

    Pan, Noren

    2015-01-01

    Phase II objectives: Develop and refine antireflection coatings incorporating lanthanum titanate as an intermediate refractive index material; Investigate wet/dry thermal oxidation of aluminum containing semiconductor compounds as a means of forming a more transparent window layer with equal or better optical properties than its unoxidized form; Develop a fabrication process that allows integration of the oxidized window layer and maintains the necessary electrical properties for contacting the solar cell; Conduct an experimental demonstration of the best candidates for improved antireflection coatings.

  2. Computational Science with the Titan Supercomputer: Early Outcomes and Lessons Learned

    Science.gov (United States)

    Wells, Jack

    2014-03-01

    Modeling and simulation with petascale computing has supercharged the process of innovation and understanding, dramatically accelerating time-to-insight and time-to-discovery. This presentation will focus on early outcomes from the Titan supercomputer at the Oak Ridge National Laboratory. Titan has over 18,000 hybrid compute nodes consisting of both CPUs and GPUs. In this presentation, I will discuss the lessons we have learned in deploying Titan and preparing applications to move from conventional CPU architectures to a hybrid machine. I will present early results of materials applications running on Titan and the implications for the research community as we prepare for exascale supercomputer in the next decade. Lastly, I will provide an overview of user programs at the Oak Ridge Leadership Computing Facility with specific information how researchers may apply for allocations of computing resources. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

  3. Drag resistance of ship hulls: Effects of surface roughness of newly applied fouling control coatings, coating water absorption, and welding seams

    DEFF Research Database (Denmark)

    Wang, Xueting; Olsen, Stefan Møller; Andrés, Eduardo

    2018-01-01

    selected, that a so-called fouling release (FR) coating caused approximately 5.6 % less skin friction (torque) over time than traditional biocide-based antifouling (AF) coatings at a tangential speed of 12 knots. Furthermore, results of immersion experiments and supporting “standard” water absorption......Fouling control coatings (FCCs) and irregularities (e.g. welding seams) on ship hull surfaces have significant effects on the overall drag performance of ships. In this work, skin frictions of four newly applied FCCs were compared using a pilot-scale rotary setup. Particular attention was given...

  4. Titan Orbiter Aerorover Mission

    Science.gov (United States)

    Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.

    2001-01-01

    We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.

  5. Titan AVIATR - Aerial Vehicle for In Situ and Airborne Titan Reconnaissance

    Science.gov (United States)

    Kattenhorn, Simon A.; Barnes, J. W.; McKay, C. P.; Lemke, L.; Beyer, R. A.; Radebaugh, J.; Adamkovics, M.; Atkinson, D. H.; Burr, D. M.; Colaprete, T.; Foch, R.; Le Mouélic, S.; Merrison, J.; Mitchell, J.; Rodriguez, S.; Schaller, E.

    2010-10-01

    Titan AVIATR - Aerial Vehicle for In Situ and Airborne Titan Reconnaissance - is a small (120 kg), nuclear-powered Titan airplane in the Discovery/New Frontiers class based on the concept of Lemke (2008 IPPW). The scientific goals of the mission are designed around the unique flexibility offered by an airborne platform: to explore Titan's diversity of surface landforms, processes, and compositions, as well as to study and measure the atmospheric circulation, aerosols, and humidity. AVIATR would address and surpass many of the science goals of hot-air balloons in Titan flagship studies. The strawman instrument payload is narrowly focused on the stated scientific objectives. The optical remote sensing suite comprises three instruments - an off-nadir high-resolution 2-micron camera, a horizon-looking 5-micron imager, and a 1-6 micron pushbroom near-infrared spectrometer. The in situ instruments include atmospheric structure, a methane humidity sensor, and a raindrop detector. An airplane has operational advantages over a balloon. Its piloted nature allows a go-to capability to image locations of interest in real time, thereby allowing for directed exploration of many features of primary geologic interest: Titan's sand dunes, mountains, craters, channels, and lakes. Subsequent imaging can capture changes in these features during the primary mission. AVIATR can fly predesigned routes, building up large context mosaics of areas of interest before swooping down to low altitude to acquire high-resolution images at 30-cm spatial sampling, similar to that of HiRISE at Mars. The elevation flexibility of the airplane allows us to acquire atmospheric profiles as a function of altitude at any desired location. Although limited by the direct-to-Earth downlink bandwidth, the total scientific data return from AVIATR will be >40 times that returned from Huygens. To maximize the science per bit, novel data storage and downlink techniques will be employed, including lossy compression

  6. Titan's greenhouse and antigreenhouse effects

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, James B.; Courtin, Regis

    1992-01-01

    Thermal mechanisms active in Titan's atmosphere are discussed in a brief review of data obtained during the Voyager I flyby in 1980. Particular attention is given to the greenhouse effect (GHE) produced by atmospheric H2, N2, and CH4; this GHE is stronger than that on earth, with CH4 and H2 playing roles similar to those of H2O and CO2 on earth. Also active on Titan is an antigreenhouse effect, in which dark-brown and orange organic aerosols block incoming solar light while allowing IR radiation from the Titan surface to escape. The combination of GHE and anti-GHE leads to a surface temperature about 12 C higher than it would be if Titan had no atmosphere.

  7. Titan Orbiter with Aerorover Mission (TOAM)

    Science.gov (United States)

    Sittler, Edward C.; Cooper, J. F.; Mahaffey, P.; Esper, J.; Fairbrother, D.; Farley, R.; Pitman, J.; Kojiro, D. R.; TOAM Team

    2006-12-01

    We propose to develop a new mission to Titan called Titan Orbiter with Aerorover Mission (TOAM). This mission is motivated by the recent discoveries of Titan, its atmosphere and its surface by the Huygens Probe, and a combination of in situ, remote sensing and radar mapping measurements of Titan by the Cassini orbiter. Titan is a body for which Astrobiology (i.e., prebiotic chemistry) will be the primary science goal of any future missions to it. TOAM is planned to use an orbiter and balloon technology (i.e., aerorover). Aerobraking will be used to put payload into orbit around Titan. The Aerorover will probably use a hot air balloon concept using the waste heat from the MMRTG 500 watts. Orbiter support for the Aerorover is unique to our approach for Titan. Our strategy to use an orbiter is contrary to some studies using just a single probe with balloon. Autonomous operation and navigation of the Aerorover around Titan will be required, which will include descent near to the surface to collect surface samples for analysis (i.e., touch and go technique). The orbiter can provide both relay station and GPS roles for the Aerorover. The Aerorover will have all the instruments needed to sample Titan’s atmosphere, surface, possible methane lakes-rivers, use multi-spectral imagers for surface reconnaissance; to take close up surface images; take core samples and deploy seismometers during landing phase. Both active and passive broadband remote sensing techniques will be used for surface topography, winds and composition measurements.

  8. The Titan haze revisted: Magnetospheric energy sorces quantitative tholin yields

    Science.gov (United States)

    Thompson, W. Reid; Mcdonald, Gene D.; Sagan, Carl

    1994-01-01

    We present laboratory measurements of the radiation yields of complex organic solids produced from N2/CH4 gas mixtures containing 10 or 0.1% CH4. These tholins are thought to resemble organic aerosols produced in the atmospheres of Titan, Pluto, and Triton. The tholin yields are large compared to the total yield of gaseous products: nominally, 13 (C + N)/100 eV for Titan tholin and 2.1 (C + N)/100 eV for Triton tholin. High-energy magnetospheric electrons responsible for tholin production represents a class distinct from the plasma electrons considered in models of Titan's aiglow. Electrons with E greater than 20 keV provide an energy flux approximately 1 x 10(exp -2) erg/cm/sec, implying from our measured tholin yields a mass flux of 0.5 to 4.0 x 10(exp -14) g/sq cm/sec of tholin. (The corresponding thickness of the tholin sedimentary column accumulated over 4 Gyr on Titan's surface is 4 to 30 m). This figure is in agreement with required mass fluxes computed from recent radiative transfer and sedimentation models. If, however, theses results, derived from experiments at approximately 2 mb, are applied to lower pressure levels toward peak auroral electron energy deposition and scaled with pressure as the gas-phase organic yields, the derived tholin mass flux is at least an order of magnitude less. We attrribute this difference to the fact that tholin synthesis occurs well below the level of maximum electron energy depositon and to possible contributions to tholis from UV-derived C2-hydrocarbons. We conclude that Tita tholin, produced by magnetospheric electrons, is alone sufficient to supply at least a significant fraction of Titan's haze-a result consistent with the fact that the optical properties of Titan tholin, among all proposed material, are best at reproducing Titan's geometric albedo spectrum from near UV to mid-IR in light-scattering models.

  9. Are Titan's radial Labyrinth terrains surface expressions of large laccoliths?

    Science.gov (United States)

    Schurmeier, L.; Dombard, A. J.; Malaska, M.; Radebaugh, J.

    2017-12-01

    The Labyrinth terrain unit may be the one of the best examples of the surface expression of Titan's complicated history. They are characterized as highly eroded, dissected, and elevated plateaus and remnant ridges, with an assumed composition that is likely organic-rich based on radar emissivity. How these features accumulated organic-rich sediments and formed topographic highs by either locally uplifting or surviving pervasive regional deflation or erosion is an important question for understanding the history of Titan. There are several subsets of Labyrinth terrains, presumably with differing evolutionary histories and formation processes. We aim to explain the formation of a subset of Labyrinth terrain units informally referred to as "radial Labyrinth terrains." They are elevated and appear dome-like, circular in planform, have a strong radial dissection pattern, are bordered by Undifferentiated Plains units, and are found in the mid-latitudes. Based on their shape, clustering, and dimensions, we suggest that they may be the surface expression of large subsurface laccoliths. A recent study by Manga and Michaut (Icarus, 2017) explained Europa's lenticulae (pits, domes, spots) with the formation of saucer-shaped sills that form laccoliths around the brittle-ductile transition depth within the ice shell (1-5 km). Here, we apply the same scaling relationships and find that the larger size of radial labyrinth terrains with Titan's higher gravity implies deeper intrusion depths of around 20-40 km. This intrusion depth matches the expected brittle-ductile transition on Titan based on our finite element simulations and yield strength envelope analyses. We hypothesize that Titan's radial labyrinth terrains formed as cryovolcanic (water) intrusions that rose to the brittle-ductile transition within the ice shell where they spread horizontally, and uplifted the overlying ice. The organic-rich sedimentary cover also uplifted, becoming more susceptible to pluvial and fluvial

  10. Comparison of TITAN hybrid deterministic transport code and MCNP5 for simulation of SPECT

    International Nuclear Information System (INIS)

    Royston, K.; Haghighat, A.; Yi, C.

    2010-01-01

    Traditionally, Single Photon Emission Computed Tomography (SPECT) simulations use Monte Carlo methods. The hybrid deterministic transport code TITAN has recently been applied to the simulation of a SPECT myocardial perfusion study. The TITAN SPECT simulation uses the discrete ordinates formulation in the phantom region and a simplified ray-tracing formulation outside of the phantom. A SPECT model has been created in the Monte Carlo Neutral particle (MCNP)5 Monte Carlo code for comparison. In MCNP5 the collimator is directly modeled, but TITAN instead simulates the effect of collimator blur using a circular ordinate splitting technique. Projection images created using the TITAN code are compared to results using MCNP5 for three collimator acceptance angles. Normalized projection images for 2.97 deg, 1.42 deg and 0.98 deg collimator acceptance angles had maximum relative differences of 21.3%, 11.9% and 8.3%, respectively. Visually the images are in good agreement. Profiles through the projection images were plotted to find that the TITAN results followed the shape of the MCNP5 results with some differences in magnitude. A timing comparison on 16 processors found that the TITAN code completed the calculation 382 to 2787 times faster than MCNP5. Both codes exhibit good parallel performance. (author)

  11. Modeling of synchrotron-based laboratory simulations of Titan's ionospheric photochemistry

    Science.gov (United States)

    Carrasco, Nathalie; Peng, Zhe; Pernot, Pascal

    2014-11-01

    The APSIS reactor has been designed to simulate in the laboratory with a VUV synchrotron irradiation the photochemistry occurring in planetary upper atmospheres. A N2-CH4 Titan-like gas mixture has been studied, whose photochemistry in Titan's ionospheric irradiation conditions leads to a coupled chemical network involving both radicals and ions. In the present work, an ion-neutral coupled model is developed to interpret the experimental data, taking into account the uncertainties on the kinetic parameters by Monte Carlo sampling. The model predicts species concentrations in agreement with mass spectrometry measurements of the methane consumption and product blocks intensities. Ion chemistry and in particular dissociative recombination are found to be very important through sensitivity analysis. The model is also applied to complementary environmental conditions, corresponding to Titan's ionospheric average conditions and to another existing synchrotron setup. An innovative study of the correlations between species concentrations identifies two main competitive families, leading respectively to saturated and unsaturated species. We find that the unsaturated growth family, driven by C2H2 , is dominant in Titan's upper atmosphere, as observed by the Cassini INMS. But the saturated species are substantially more intense in the measurements of the two synchrotron experimental setups, and likely originate from catalysis by metallic walls of the reactors.

  12. Probing Small Lakes on Titan Using the Cassini RADAR Altimeter

    Science.gov (United States)

    Mastrogiuseppe, M.; Poggiali, V.; Hayes, A.; Lunine, J. I.; Seu, R.; Lorenz, R. D.; Mitri, G.; Mitchell, K. L.; Janssen, M. A.; Casarano, D.; Notarnicola, C.; Le Gall, A. A.

    2017-12-01

    The T126 Cassini's final flyby of Titan has offered a unique opportunity to observe an area in the Northern Polar terrain, where several small - medium size (10 - 50 km) hydrocarbon lakes are present and have been previously imaged by Cassini. The successful observation allowed the radar to operate at the closest approach over several small lakes, using its altimetry mode for the investigation of depth and liquid composition. Herein we present the result of a dedicate processing previously applied to altimetric data acquired over Ligeia Mare where the radar revealed the bathymetry and composition of the sea [1,2]. We show that, the optimal geometry condition met during the T126 fly-by allowed the radar to probe Titan's lakes revealing that such small liquid bodies can exceed one-hundred meters of depth. [1] M. Mastrogiuseppe et al. (2014, Mar.). The bathymetry of a Titan Sea. Geophysical Research Letters. [Online]. 41 (5), pp. 1432-1437. Available: http://dx.doi.org/10.1002/2013GL058618 [2] M.Mastrogiuseppe et al. (2016, Oct). Radar Sounding Using the Cassini Altimeter: Waveform Modeling and Monte Carlo Approach for Data Inversion of Observations of Titan's Seas, IEEE Transactions On Geoscience And Remote Sensing, Vol. 54, No. 10, doi: 10.1109/TGRS.2016.2563426.

  13. Organic chemistry on Titan: Surface interactions

    Science.gov (United States)

    Thompson, W. Reid; Sagan, Carl

    1992-01-01

    The interaction of Titan's organic sediments with the surface (solubility in nonpolar fluids) is discussed. How Titan's sediments can be exposed to an aqueous medium for short, but perhaps significant, periods of time is also discussed. Interactions with hydrocarbons and with volcanic magmas are considered. The alteration of Titan's organic sediments over geologic time by the impacts of meteorites and comets is discussed.

  14. AVIATR - Aerial Vehicle for In-situ and Airborne Titan Reconnaissance A Titan Airplane Mission Concept

    Science.gov (United States)

    Barnes, Jason W.; Lemke, Lawrence; Foch, Rick; McKay, Christopher P.; Beyer, Ross A.; Radebaugh, Jani; Atkinson, David H.; Lorenz, Ralph D.; LeMouelic, Stephane; Rodriguez, Sebastien; hide

    2011-01-01

    We describe a mission concept for a stand-alone Titan airplane mission: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR). With independent delivery and direct-to-Earth communications, AVIATR could contribute to Titan science either alone or as part of a sustained Titan Exploration Program. As a focused mission, AVIATR as we have envisioned it would concentrate on the science that an airplane can do best: exploration of Titan's global diversity. We focus on surface geology/hydrology and lower-atmospheric structure and dynamics. With a carefully chosen set of seven instruments-2 near-IR cameras, 1 near-IR spectrometer, a RADAR altimeter, an atmospheric structure suite, a haze sensor, and a raindrop detector-AVIATR could accomplish a significant subset of the scientific objectives of the aerial element of flagship studies. The AVIATR spacecraft stack is composed of a Space Vehicle (SV) for cruise, an Entry Vehicle (EV) for entry and descent, and the Air Vehicle (AV) to fly in Titan's atmosphere. Using an Earth-Jupiter gravity assist trajectory delivers the spacecraft to Titan in 7.5 years, after which the AVIATR AV would operate for a 1-Earth-year nominal mission. We propose a novel 'gravity battery' climb-then-glide strategy to store energy for optimal use during telecommunications sessions. We would optimize our science by using the flexibility of the airplane platform, generating context data and stereo pairs by flying and banking the AV instead of using gimbaled cameras. AVIATR would climb up to 14 km altitude and descend down to 3.5 km altitude once per Earth day, allowing for repeated atmospheric structure and wind measurements all over the globe. An initial Team-X run at JPL priced the AVIATR mission at FY10 $715M based on the rules stipulated in the recent Discovery announcement of opportunity. Hence we find that a standalone Titan airplane mission can achieve important science building on Cassini's discoveries and can likely do so within

  15. TSSM: The in situ exploration of Titan

    Science.gov (United States)

    Coustenis, A.; Lunine, J. I.; Lebreton, J. P.; Matson, D.; Reh, K.; Beauchamp, P.; Erd, C.

    2008-09-01

    The Titan Saturn System Mission (TSSM) mission was born when NASA and ESA decided to collaborate on two missions independently selected by each agency: the Titan and Enceladus mission (TandEM), and Titan Explorer, a 2007 Flagship study. TandEM, the Titan and Enceladus mission, was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call. The mission concept is to perform remote and in situ investigations of Titan primarily, but also of Enceladus and Saturn's magentosphere. The two satellites are tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TSSM will study Titan as a system, including its upper atmosphere, the interactions with the magnetosphere, the neutral atmosphere, surface, interior, origin and evolution, as well as the astrobiological potential of Titan. It is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini- Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time for Titan, several close flybys of Enceladus). One overarching goal of the TSSM mission is to explore in situ the atmosphere and surface of Titan. In the current mission architecture, TSSM consists of an orbiter (under NASA's responsibility) with a large host of instruments which would perform several Enceladus and Titan flybys before stabilizing in an orbit around Titan alone, therein delivering in situ elements (a Montgolfière, or hot air balloon, and a probe/lander). The latter are being studied by ESA. The balloon will circumnavigate Titan above the equator at an altitude of about 10 km for several months. The

  16. Diurnal variations of Titan

    Science.gov (United States)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Kasprzak, W. T.; Waite, J. H.

    2009-04-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1,000 and 1,400 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from 8 close encounters of the Cassini spacecraft with Titan. Though there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ~700 cm-3 below ~1,300 km. Such a plateau is associated with the combination of distinct diurnal variations of light and heavy ions. Light ions (e.g. CH5+, HCNH+, C2H5+) show strong diurnal variation, with clear bite-outs in their nightside distributions. In contrast, heavy ions (e.g. c-C3H3+, C2H3CNH+, C6H7+) present modest diurnal variation, with significant densities observed on the nightside. We propose that the distinctions between light and heavy ions are associated with their different chemical loss pathways, with the former primarily through "fast" ion-neutral chemistry and the latter through "slow" electron dissociative recombination. The INMS data suggest day-to-night transport as an important source of ions on Titan's nightside, to be distinguished from the conventional scenario of auroral ionization by magnetospheric particles as the only ionizing source on the nightside. This is supported by the strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes. We construct a time-dependent ion chemistry model to investigate the effects of day-to-night transport on the ionospheric structures of Titan. The predicted diurnal variation has similar general characteristics to those observed, with some apparent discrepancies which could be reconciled by imposing fast horizontal thermal winds in Titan's upper atmosphere.

  17. Amino acidis derived from Titan tholins

    Science.gov (United States)

    Khare, Bishun N.; Sagan, Carl; Ogino, Hiroshi; Nagy, Bartholomew; Er, Cevat

    1986-01-01

    The production of amino acids by acid treatment of Titan tholin is experimentally investigated. The synthesis of Titan tholin and the derivatization of amino acids to N-trifluoroacetyl isopropyl esters are described. The gas chromatography/mass spectroscopy analysis of the Titan tholins reveals the presence of glycine, alpha and beta alainine, and aspartic acid, and the total yield of amino acids is about 0.01.

  18. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    International Nuclear Information System (INIS)

    Solanki, Anjana; Choudhary, Surbhi; Satsangi, Vibha R.; Shrivastav, Rohit; Dass, Sahab

    2013-01-01

    Highlights: ► Effect of 100 MeV Si 8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO 3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 10 11 ion cm −2 . ► Maximum photocurrent density was observed to be 0.7 mA cm −2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO 3 ) thin films were investigated by irradiating films with 100 MeV Si 8+ ions at different ion fluences in the range of 1 × 10 11 –2 × 10 13 ions cm −2 . BaTiO 3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm −2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO 3 film irradiated at 5 × 10 11 ions cm −2 , which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  19. Bismuth titanate nanorods and their visible light photocatalytic properties

    International Nuclear Information System (INIS)

    Pei, L.Z.; Liu, H.D.; Lin, N.; Yu, H.Y.

    2015-01-01

    Highlights: • Bismuth titanate nanorods have been synthesized by a simple hydrothermal process. • The size of bismuth titanate nanorods can be controlled by growth conditions. • Bismuth titanate nanorods show good photocatalytic activities of methylene blue and Rhodamine B. - Abstract: Bismuth titanate nanorods have been prepared using a facile hydrothermal process without additives. The bismuth titanate products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and UV-vis diffusion reflectance spectrum. XRD pattern shows that the bismuth titanate nanorods are composed of cubic Bi 2 Ti 2 O 7 phase. Electron microscopy images show that the length and diameter of the bismuth titanate nanorods are 50-200 nm and 2 μm, respectively. Hydrothermal temperature and reaction time play important roles on the formation and size of the bismuth titanate nanorods. UV-vis diffusion reflectance spectrum indicates that bismuth titanate nanorods have a band gap of 2.58 eV. The bismuth titanate nanorods exhibit good photocatalytic activities in the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RB) under visible light irradiation. The bismuth titanate nanorods with cubic Bi 2 Ti 2 O 7 phase are a promising candidate as a visible light photocatalyst

  20. Spectroscopic investigation on the interaction of titanate nanotubes with bovine serum albumin

    International Nuclear Information System (INIS)

    Zhao, L.Z.; Zhao, Y.S.; Teng, H.H.; Shi, S.Y.; Ren, B.X.

    2014-01-01

    In order to understand the transport mechanism and evaluate the biological safety of titanate nanotubes, the interactions of titanate nanotubes (TNTs) with bovine serum albumin (BSA) were investigated by applying spectroscopic methods under simulated physiological conditions. After taking into account the inner filter effect, the fluorescence intensity of BSA was found to be significantly enhanced by the presence of TNTs, indicating that the microenvironment of tryptophan and tyrosine residues in BSA became more hydrophobic. In addition, the absorption spectra of BSA showed a hyperchromic effect around 280 nm as the concentration of TNTs increased, suggesting that TNTs changed the microenvironment of the tryptophan and tyrosine residues. This is consistent with the results from fluorescence spectroscopy studies. However, circular dichroism spectroscopy revealed that no significant conformational change in BSA occurred during the interaction. We believe that Trp-213 was buried more compactly in the internal hydrophobic region, and hydrophobicity increased around Trp-134 with increasing TNTs concentration. From a spectroscopic point of view, this work elucidates the interaction mechanism of titanate nanotubes with BSA, and the methods used in this paper can also be applied to explore the molecular mechanism underlying toxicity of other nanomaterials. (authors)

  1. Hubble Observes Surface of Titan

    Science.gov (United States)

    1994-01-01

    Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia.Titan, larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface, albeit oceans and rain of ethane-methane rather than water. Scientists suspect that Titan's present environment -- although colder than minus 289 degrees Fahrenheit, so cold that water ice would be as hard as granite -- might be similar to that on Earth billions of years ago, before life began pumping oxygen into the atmosphere.Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory and his team took the images with the Hubble Space Telescope during 14 observing runs between Oct. 4 - 18. Smith announced the team's first results last week at the 26th annual meeting of the American Astronomical Society Division for Planetary Sciences in Bethesda, Md. Co-investigators on the team are Mark Lemmon, a doctoral candidate with the UA Lunar and Planetary Laboratory; John Caldwell of York University, Canada; Larry Sromovsky of the University of Wisconsin; and Michael Allison of the Goddard Institute for Space Studies, New York City.Titan's atmosphere, about four times as dense as Earth's atmosphere, is primarily nitrogen laced with such poisonous substances as methane and ethane. This thick, orange, hydrocarbon haze was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The haze is formed as methane in the atmosphere is destroyed by sunlight. The hydrocarbons produced by this methane destruction form a smog similar to that found over large cities, but is much thicker

  2. The rotation of Titan and Ganymede

    Science.gov (United States)

    Van Hoolst, Tim; Coyette, Alexis; Baland, Rose-Marie; Trinh, Antony

    2016-10-01

    The rotation rates of Titan and Ganymede, the largest satellites of Saturn and Jupiter, are on average equal to their orbital mean motion. Here we discuss small deviations from the average rotation for both satellites and evaluate the polar motion of Titan induced by its surface fluid layers. We examine different causes at various time scales and assess possible consequences and the potential of using librations and polar motion as probes of the interior structure of the satellites.The rotation rate of Titan and Ganymede cannot be constant on the orbital time scale as a result of the gravitational torque of the central planet acting on the satellites. Titan is moreover expected to show significant polar motion and additional variations in the rotation rate due to angular momentum exchange with the atmosphere, mainly at seasonal periods. Observational evidence for deviations from the synchronous state has been reported several times for Titan but is unfortunately inconclusive. The measurements of the rotation variations are based on determinations of the shift in position of Cassini radar images taken during different flybys. The ESA JUICE (JUpiter ICy moons Explorer) mission will measure the rotation variations of Ganymede during its orbital phase around the satellite starting in 2032.We report on different theoretical aspects of the librations and polar motion. We consider the influence of the rheology of the ice shell and take into account Cassini measurements of the external gravitational field and of the topography of Titan and similar Galileo data about Ganymede. We also evaluate the librations and polar motion induced by Titan's hydrocarbon seas and use the most recent results of Titan's atmosphere dynamics. We finally evaluate the potential of rotation variations to constrain the satellite's interior structure, in particular its ice shell and ocean.

  3. Future Exploration of Titan and Enceladus

    Science.gov (United States)

    Matson, D. L.; Coustenis, A.; Lunine, J.; Lebreton, J.; Reh, K.; Beauchamp, P.

    2009-05-01

    The future exploration of Titan and Enceladus has become very important for the planetary community. The study conducted last year of the Titan Saturn System Mission (TSSM) led to an announcement in which ESA and NASA prioritized future OPF missions, stating that TSSM is planned after EJSM (for details see http://www.lpi.usra.edu/opag/). TSSM consists of a TSSM Orbiter that would carry two in situ elements: the Titan Montgolfiere hot air balloon and the Titan Lake Lander. The mission could launch in the 2023-2025 timeframe on a trajectory to arrive ~9 years later for a 4-year mission in the Saturn system. Soon after arrival at Saturn, the montgolfiere would be delivered to Titan to begin its mission of airborne, scientific observations of Titan from an altitude of about 10 km. The montgolfiere would have a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) power system and would be designed to last at least 6-12 months in Titan's atmosphere. With the predicted winds and weather, that would be sufficient to circumnavigate the globe! On a subsequent fly-by, the TSSM orbiter would release the Lake Lander on a trajectory toward Titan for a targeted entry. It would descend through the atmosphere making scientific measurements, much like Huygens did, and then land and float on one of Titan's seas. This would be its oceanographic phase, making a physical and chemical assessment of the sea. The Lake Lander would operate 8-10 hours until its batteries become depleted. Following the delivery of the in situ elements, the TSSM orbiter would explore the Saturn system via a 2-year tour that includes in situ sampling of Enceladus' plumes as well as Titan flybys. After the Saturn system tour, the TSSM orbiter would enter orbit around Titan for a global survey phase. Synergistic and coordinated observations would be carried out between the TSSM orbiter and the in situ elements. The scientific requirements were developed by the international TSSM Joint Science Definition

  4. Clash of the Titans

    Science.gov (United States)

    Subramaniam, Karthigeyan

    2010-01-01

    WebQuests and the 5E learning cycle are titans of the science classroom. These popular inquiry-based strategies are most often used as separate entities, but the author has discovered that using a combined WebQuest and 5E learning cycle format taps into the inherent power and potential of both strategies. In the lesson, "Clash of the Titans,"…

  5. TITAN'S TRANSPORT-DRIVEN METHANE CYCLE

    International Nuclear Information System (INIS)

    Mitchell, Jonathan L.

    2012-01-01

    The mechanisms behind the occurrence of large cloud outbursts and precipitation on Titan have been disputed. A global- and annual-mean estimate of surface fluxes indicated only 1% of the insolation, or ∼0.04 W m –2 , is exchanged as sensible and/or latent fluxes. Since these fluxes are responsible for driving atmospheric convection, it has been argued that moist convection should be quite rare and precipitation even rarer, even if evaporation globally dominates the surface-atmosphere energy exchange. In contrast, climate simulations indicate substantial cloud formation and/or precipitation. We argue that the top-of-atmosphere (TOA) radiative imbalance is diagnostic of horizontal heat transport by Titan's atmosphere, and thus constrains the strength of the methane cycle. Simple calculations show the TOA radiative imbalance is ∼0.5-1 W m –2 in Titan's equatorial region, which implies 2-3 MW of latitudinal heat transport by the atmosphere. Our simulation of Titan's climate suggests this transport may occur primarily as latent heat, with net evaporation at the equator and net accumulation at higher latitudes. Thus, the methane cycle could be 10-20 times previous estimates. Opposing seasonal transport at solstices, compensation by sensible heat transport, and focusing of precipitation by large-scale dynamics could further enhance the local, instantaneous strength of Titan's methane cycle by a factor of several. A limited supply of surface liquids in regions of large surface radiative imbalance may throttle the methane cycle, and if so, we predict more frequent large storms over the lakes district during Titan's northern summer.

  6. Radiation stability of sodium titanate ion exchange materials

    International Nuclear Information System (INIS)

    Kenna, B.T.

    1980-02-01

    Sodium titanate and sodium titanate loaded macroreticular resin are being considered as ion exchangers to remove 90 Sr and actinides from the large volume of defense waste stored at Hanford Site in Washington. Preliminary studies to determine the radiation effect on Sr +2 and I - capacity of these ion-exchange materials were conducted. Samples of sodium titanate powder, sodium titanate loaded macroreticular resin, as well as the nitrate form of macroreticular anion resin were irradiated with up to 2 x 10 9 Rads of 60 Co gamma rays. Sodium titanate cation capacity decreased about 50% while the sodium titanate loaded macroeticular resin displayed a dramatic decrease in cation capacity when irradiated with 10 8 -10 9 Rad. The latter decrease is tentatively ascribed to radiation damage to the organic portion which subsequently inhibits interaction with the contained sodium titanate. The anion capacity of both macroreticular resin and sodium titanate loaded macroreticular resin exhibited significant decreases with increasing radiation exposure. These results suggest that consideration should be given to the potential effects of radiation degradation if column regeneration is to be used. 5 figures, 2 tables

  7. Chemical investigation of Titan and Triton tholins

    Science.gov (United States)

    Mcdonald, Gene D.; Thompson, W. R.; Heinrich, Michael; Khare, Bishun N.; Sagan, Carl

    1994-01-01

    We report chromatographic and spectroscopic analyses of both Titan and Triton tholins, organic solids made from the plasma irradiation of 0.9:0.1 and 0.999:0.001 N2/CH4 gas mixtures, respectively. The lower CH4 mixing ratio leads to a nitrogen-richer tholin (N/C greater than 1), probably including nitrogen heterocyclic compounds. Unlike Titan tholin, bulk Triton tholin is poor in nitriles. From high-pressure liquid chromatography, ultraviolet and infrared spectroscopy, and molecular weight estimation by gel filtration chromatography, we conclude that (1) several H2O-soluble fractions, each with distinct UV and IR spectral signatures, are present, (2) these fractions are not identical in the two tholins, (3) the H2O-soluble fractions of Titan tholins do not contain significant amounts of nitriles, despite the major role of nitriles in bulk Titan tholin, and (4) the H2O-soluble fractions of both tholins are mainly molcules containing about 10 to 50 (C + N) atoms. We report yields of amino acids upon hydrolysis of Titan and Triton tholins. Titan tholin is largely insoluble in the putative hydrocarbon lakes or oceans on Titan, but can yield the H2O-soluble species investigated here upon contact with transient (e.g., impact-generated) liquid water.

  8. Ferroelectric and Piezoelectric properties of (111) oriented lanthanum modified lead zirconate titanate film

    International Nuclear Information System (INIS)

    Dutta, Soma; Antony Jeyaseelan, A.; Sruthi, S.

    2014-01-01

    Lanthanum modified lead zirconate titanate (PLZT) thick film with molecular formula of Pb 0.92 La 0.08 (Zr 0.52 Ti 0.48 ) 0.98 O 3 was grown preferentially along (111) direction on Pt/SiO 2 /Si (platinum/silicon oxide/silicon) substrate by spin coating of chemical solution. The directional growth of the film was facilitated by platinum (Pt) (111) template and rapid thermal annealing. X-ray diffraction pattern and atomic force microscopy revealed the preferential growth of the PLZT film. The film was characterized for ferroelectric and detailed piezoelectric properties in a parallel plate capacitor (metal–PLZT–metal) configuration. Ferroelectric characterization of the film showed saturated hysteresis loop with remanent polarization and coercive electric field values of 10.14 μC/cm 2 and 42 kV/cm, respectively, at an applied field of 300 kV/cm. Longitudinal piezoelectric coefficient (d 33,f ) was measured by employing converse piezoelectric effect where electrical charge response and displacement were measured with electrical voltage excitation on the sample electrodes. The effective transverse piezoelectric coefficient (e 31,f ) was derived from charge measurement with an applied mechanical excitation strain by using the four point bending method. d 33,f and e 31,f coefficients of PLZT films were found to be 380 pm/V and − 0.831 C/m 2 respectively. - Highlights: • PLZT (111) film is prepared by spin coating of chemical sol on Pt (111) template. • Piezoelectric d 33 value (380 pm/V) of PLZT film is found 20% higher than PZT. • Transverse piezocoefficient e 31,f of PLZT film is reported for the first time

  9. The Exploration of Titan and the Saturnian System

    Science.gov (United States)

    Coustenis, Athena

    The exploration of the outer solar system and in particular of the giant planets and their environments is an on-going process with the Cassini spacecraft currently around Saturn, the Juno mission to Jupiter preparing to depart and two large future space missions planned to launch in the 2020-2025 time frame for the Jupiter system and its satellites (Europa and Ganymede) on the one hand, and the Saturnian system and Titan on the other hand [1,2]. Titan, Saturn's largest satellite, is the only other object in our Solar system to possess an extensive nitrogen atmosphere, host to an active organic chemistry, based on the interaction of N2 with methane (CH4). Following the Voyager flyby in 1980, Titan has been intensely studied from the ground-based large telescopes (such as the Keck or the VLT) and by artificial satellites (such as the Infrared Space Observatory and the Hubble Space Telescope) for the past three decades. Prior to Cassini-Huygens, Titan's atmospheric composition was thus known to us from the Voyager missions and also through the explorations by the ISO. Our perception of Titan had thus greatly been enhanced accordingly, but many questions remained as to the nature of the haze surrounding the satellite and the composition of the surface. The recent revelations by the Cassini-Huygens mission have managed to surprise us with many discoveries [3-8] and have yet to reveal more of the interesting aspects of the satellite. The Cassini-Huygens mission to the Saturnian system has been an extraordinary success for the planetary community since the Saturn-Orbit-Insertion (SOI) in July 2004 and again the very successful probe descent and landing of Huygens on January 14, 2005. One of its main targets was Titan. Titan was revealed to be a complex world more like the Earth than any other: it has a dense mostly nitrogen atmosphere and active climate and meteorological cycles where the working fluid, methane, behaves under Titan conditions the way that water does on

  10. Seasonal Changes in Titan's Meteorology

    Science.gov (United States)

    Turtle, E. P.; DelGenio, A. D.; Barbara, J. M.; Perry, J. E.; Schaller, E. L.; McEwen, A. S.; West, R. A.; Ray, T. L.

    2011-01-01

    The Cassini Imaging Science Subsystem has observed Titan for 1/4 Titan year, and we report here the first evidence of seasonal shifts in preferred locations of tropospheric methane clouds. South \\polar convective cloud activity, common in late southern summer, has become rare. North \\polar and northern mid \\latitude clouds appeared during the approach to the northern spring equinox in August 2009. Recent observations have shown extensive cloud systems at low latitudes. In contrast, southern mid \\latitude and subtropical clouds have appeared sporadically throughout the mission, exhibiting little seasonality to date. These differences in behavior suggest that Titan s clouds, and thus its general circulation, are influenced by both the rapid temperature response of a low \\thermal \\inertia surface and the much longer radiative timescale of Titan s cold thick troposphere. North \\polar clouds are often seen near lakes and seas, suggesting that local increases in methane concentration and/or lifting generated by surface roughness gradients may promote cloud formation. Citation

  11. Maintenance procedures for the TITAN-I and TITAN-II reversed field pinch reactors

    International Nuclear Information System (INIS)

    Grotz, S.P.; Duggan, W.; Krakowski, R.; Najmabadi, F.; Wong, C.P.C.

    1989-01-01

    The TITAN reactor is a compact, high-power-density (neutron wall loading 18 MW/m 2 ) machine, based on the reversed-field-pinch (RFP) confinement concept. Two designs for the fusion power core have been examined: TITAN-I is based on a self-cooled lithium loop with a vanadium-alloy structure for the first wall, blanket and shield; and TITAN-II is based on an aqueous loop-in-pool design with a LiNO 3 solution as the coolant and breeder. The compact design of the TITAN fusion power core, (FPC) reduces the system to a few small and relatively low mass components, making toroidal segmentation of the FPC unnecessary. A single-piece maintenance procedure is possible. The potential advantages of single-piece maintenance procedures are: (1) Short period of down time; (2) improved reliability; (3) no adverse effects resulting from unequal levels of irradiation; and (4) ability to continually modify the FPC design. Increased availability can be expected from a fully pre-tested, single-piece FPC. Pre-testing of the FPC throughout the assembly process and prior to installation into the reactor vault is discussed. (orig.)

  12. The tides of Titan.

    Science.gov (United States)

    Iess, Luciano; Jacobson, Robert A; Ducci, Marco; Stevenson, David J; Lunine, Jonathan I; Armstrong, John W; Asmar, Sami W; Racioppa, Paolo; Rappaport, Nicole J; Tortora, Paolo

    2012-07-27

    We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k(2) = 0.589 ± 0.150 and k(2) = 0.637 ± 0.224 (2σ). Such a large response to the tidal field requires that Titan's interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth.

  13. Titan through Time: Evolution of Titan's Atmosphere and its Hydrocarbon Cycle on the Surface

    Science.gov (United States)

    Gilliam, Ashley E.

    The Introduction and Appendix i-A outline briefly the history of Titan exploration since its discovery by Christiaan Huygens in 1675 through the recent International Mission of Cassini-Huygens.. Chapter 1: This chapter discusses two possible pathways of loss of the two main gases from Titan's post-accretional atmosphere, methane (CH 4) and ammonia (NH3), by the mechanisms of thermal escape and emission from the interior coupled with thermal escape. Chapter 2: In this chapter, a simple photolysis model is created, where the second most abundant component of the present-day Titan atmosphere, methane (CH4), can either escape the atmosphere or undergo photolytic conversion to ethane (C2H6). Chapter 3: This chapter examines different fluvial features on Titan, identified by the Cassini spacecraft, and evaluates the possibilities of channel formation by two mechanisms: dissolution of ice by a concentrated solution of ammonium sulfate, and by mechanical erosion by flow of liquid ammonia and liquid ethane. Chapter 4: This chapter presents: (1) new explicit mathematical solutions of mixed 1st and 2nd order chemical reactions, represented by ordinary differential first-degree and Riccati equations; (2) the computed present-day concentrations of the three gases in Titan's scale atmosphere, treated as at near-steady state; and (3) an analysis of the reported and computed atmospheric concentrations of CH4, CH 3, and C2H6 on Titan, based on the reaction rate parameters of the species, the rate parameters taken as constants representative of their mean values. Chapter 5: This chapter examines the possible reactions of methane formation in terms of the thermodynamic relationships of the reactions that include pure carbon as graphite, the gases H2, CO2, H2 O, and serpentinization and magnetite formation from olivine fayalite. (Abstract shortened by ProQuest.).

  14. Sensitivity analysis of the titan hybrid deterministic transport code for SPECT simulation

    International Nuclear Information System (INIS)

    Royston, Katherine K.; Haghighat, Alireza

    2011-01-01

    Single photon emission computed tomography (SPECT) has been traditionally simulated using Monte Carlo methods. The TITAN code is a hybrid deterministic transport code that has recently been applied to the simulation of a SPECT myocardial perfusion study. For modeling SPECT, the TITAN code uses a discrete ordinates method in the phantom region and a combined simplified ray-tracing algorithm with a fictitious angular quadrature technique to simulate the collimator and generate projection images. In this paper, we compare the results of an experiment with a physical phantom with predictions from the MCNP5 and TITAN codes. While the results of the two codes are in good agreement, they differ from the experimental data by ∼ 21%. In order to understand these large differences, we conduct a sensitivity study by examining the effect of different parameters including heart size, collimator position, collimator simulation parameter, and number of energy groups. (author)

  15. Titan LEAF: A Sky Rover Granting Targeted Access to Titan's Lakes and Plains

    Science.gov (United States)

    Ross, Floyd; Lee, Greg; Sokol, Daniel; Goldman, Benjamin; Bolisay, Linden

    2016-10-01

    Northrop Grumman, in collaboration with L'Garde Inc. and Global Aerospace Corporation (GAC), has been developing the Titan Lifting Entry Atmospheric Flight (T-LEAF) sky rover to roam the atmosphere and observe at close quarters the lakes and plains of Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in situ instruments to the surface.T-LEAF is a maneuverable, buoyant air vehicle. Its aerodynamic shape provides its maneuverability, and its internal helium envelope reduces propulsion power requirements and also the risk of crashing. Because of these features, T-LEAF is not restricted to following prevailing wind patterns. This freedom of mobility allows it be commanded to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations.T-LEAF utilizes a variable power propulsion system, from high power at ~200W to low power at ~50W. High power mode uses the propellers and control surfaces for additional mobility and maneuverability. It also allows the vehicle to hover over specific locations for long duration surface observations. Low power mode utilizes GAC's Titan Winged Aerobot (TWA) concept, currently being developed with NASA funding, which achieves guided flight without the use of propellers or control surfaces. Although slower than high powered flight, this mode grants increased power to science instruments while still maintaining control over direction of travel.Additionally, T-LEAF is its own entry vehicle, with its leading edges protected by flexible thermal protection system (f-TPS) materials already being tested by NASA's Hypersonic Inflatable Aerodynamic Decelerator (HIAD) group. This f-TPS technology allows T-LEAF to inflate in space, like HIAD, and then enter the atmosphere fully deployed. This approach accommodates entry velocities from as low as ~1.8 km/s if entering from Titan orbit, up to ~6 km/s if entering directly from Saturn orbit, like the Huygens probe

  16. Characterizing the Upper Atmosphere of Titan using the Titan Global Ionosphere- Thermosphere Model: Nitrogen and Methane.

    Science.gov (United States)

    Bell, J. M.; Waite, J. H.; Bar-Nun, A.; Bougher, S. W.; Ridley, A. J.; Magee, B.

    2008-12-01

    Recently, a great deal of effort has been put forth to explain the Cassini Ion-Neutral Mass Spectrometer (Waite et al [2004]) in-situ measurements of Titan's upper atmosphere (e.g. Muller-Wodarg [2008], Strobel [2008], Yelle et al [2008]). Currently, the community seems to agree that large amounts of CH4 are escaping from Titan's upper atmosphere at a rate of roughly 2.0 x 1027 molecules of CH4/s (3.33 x 1028 amu/s), representing a significant mass source to the Kronian Magnetosphere. However, such large escape fluxes from Titan are currently not corroborated by measurements onboard the Cassini Spacecraft. Thus, we posit another potential scenario: Aerosol depletion of atmospheric methane. Using the three-dimensional Titan Global Ionosphere-Thermosphere Model (T-GITM) (Bell et al [2008]), we explore the possible removal mechanisms of atmospheric gaseous constituents by these aerosols. Titan simulations are directly compared against Cassini Ion-Neutral Mass Spectrometer in-situ densities of N2 and CH4. From this work, we can then compare and contrast this aerosol depletion scenario against the currently posited hydrodynamic escape scenario, illustrating the merits and shortcomings of both.

  17. Diurnal variations of Titan's ionosphere

    Science.gov (United States)

    Cui, J.; Galand, M.; Yelle, R. V.; Vuitton, V.; Wahlund, J.-E.; Lavvas, P. P.; Müller-Wodarg, I. C. F.; Cravens, T. E.; Kasprzak, W. T.; Waite, J. H.

    2009-06-01

    We present our analysis of the diurnal variations of Titan's ionosphere (between 1000 and 1300 km) based on a sample of Ion Neutral Mass Spectrometer (INMS) measurements in the Open Source Ion (OSI) mode obtained from eight close encounters of the Cassini spacecraft with Titan. Although there is an overall ion depletion well beyond the terminator, the ion content on Titan's nightside is still appreciable, with a density plateau of ˜700 cm-3 below ˜1300 km. Such a plateau is a combined result of significant depletion of light ions and modest depletion of heavy ones on Titan's nightside. We propose that the distinctions between the diurnal variations of light and heavy ions are associated with their different chemical loss pathways, with the former primarily through “fast” ion-neutral chemistry and the latter through “slow” electron dissociative recombination. The strong correlation between the observed night-to-day ion density ratios and the associated ion lifetimes suggests a scenario in which the ions created on Titan's dayside may survive well to the nightside. The observed asymmetry between the dawn and dusk ion density profiles also supports such an interpretation. We construct a time-dependent ion chemistry model to investigate the effect of ion survival associated with solid body rotation alone as well as superrotating horizontal winds. For long-lived ions, the predicted diurnal variations have similar general characteristics to those observed. However, for short-lived ions, the model densities on the nightside are significantly lower than the observed values. This implies that electron precipitation from Saturn's magnetosphere may be an additional and important contributor to the densities of the short-lived ions observed on Titan's nightside.

  18. Titan the earth-like moon

    CERN Document Server

    Coustenis, Athena

    1999-01-01

    This is the first book to deal with Titan, one of the most mysterious bodies in the solar system. The largest satellite of the giant planet Saturn, Titan is itself larger than the planet Mercury, and is unique in being the only known moon with a thick atmosphere. In addition, its atmosphere bears a startling resemblance to the Earth's, but is much colder.The American and European space agencies, NASA and ESA, have recently combined efforts to send a huge robot spacecraft to orbit Saturn and land on Titan. This book provides the background to this, the greatest deep space venture of our time, a

  19. Effect of applied voltage on phase components of composite coatings prepared by micro-arc oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wenjun [Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Fang, Yu-Jing [Department of Colorectal Surgery, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060 (China); Zheng, Huade [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Tan, Guoxin [Guangdong University of Technology, Guangdong Province 510006 (China); Cheng, Haimei [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China)

    2013-10-01

    In this report, we present results from our experiments on composite coatings formed on biomedical titanium substrates by micro-arc oxidation (MAO) in constant-voltage mode. The coatings were prepared on the substrates in an aqueous electrolyte containing calcium acetate and β-glycerol phosphate disodium salt pentahydrate (β-GP). We analyzed the element distribution and phase components of the coatings prepared at different voltages by X-ray diffraction, thin-coating X-ray diffraction, electron-probe microanalysis, and Fourier-transform infrared spectroscopy. The results show that the composite coatings formed at 500 V consist of titania (TiO{sub 2}), hydroxylapatite (HA), and calcium carbonate (CaCO{sub 3}). Furthermore, the concentration of Ca, P, and Ti gradually changes with increasing applied voltage, and the phase components of the composite coatings gradually change from the bottom of the coating to the top: the bottom layer consists of TiO{sub 2}, the middle layer consists of TiO{sub 2} and HA, and the top layer consists of HA and a small amount of CaCO{sub 3}. The formation of HA directly on the coating surface by MAO technique can greatly enhance the surface bioactivity. - Highlights: • Coatings prepared on biomedical titanium substrate by micro-arc oxidation • Coatings composed of titania, hydroxyapatite and calcium carbonate • Hydroxyapatite on the coating surface can enhance the surface bioactivity.

  20. Titan and habitable planets around M-dwarfs.

    Science.gov (United States)

    Lunine, Jonathan I

    2010-01-01

    The Cassini-Huygens mission discovered an active "hydrologic cycle" on Saturn's giant moon Titan, in which methane takes the place of water. Shrouded by a dense nitrogen-methane atmosphere, Titan's surface is blanketed in the equatorial regions by dunes composed of solid organics, sculpted by wind and fluvial erosion, and dotted at the poles with lakes and seas of liquid methane and ethane. The underlying crust is almost certainly water ice, possibly in the form of gas hydrates (clathrate hydrates) dominated by methane as the included species. The processes that work the surface of Titan resemble in their overall balance no other moon in the solar system; instead, they are most like that of the Earth. The presence of methane in place of water, however, means that in any particular planetary system, a body like Titan will always be outside the orbit of an Earth-type planet. Around M-dwarfs, planets with a Titan-like climate will sit at 1 AU--a far more stable environment than the approximately 0.1 AU where Earth-like planets sit. However, an observable Titan-like exoplanet might have to be much larger than Titan itself to be observable, increasing the ratio of heat contributed to the surface atmosphere system from internal (geologic) processes versus photons from the parent star.

  1. PEROXOTITANATE- AND MONOSODIUM METAL-TITANATE COMPOUNDS AS INHIBITORS OF BACTERIAL GROWTH

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.

    2011-01-19

    Sodium titanates are ion-exchange materials that effectively bind a variety of metal ions over a wide pH range. Sodium titanates alone have no known adverse biological effects but metal-exchanged titanates (or metal titanates) can deliver metal ions to mammalian cells to alter cell processes in vitro. In this work, we test a hypothesis that metal-titanate compounds inhibit bacterial growth; demonstration of this principle is one prerequisite to developing metal-based, titanate-delivered antibacterial agents. Focusing initially on oral diseases, we exposed five species of oral bacteria to titanates for 24 h, with or without loading of Au(III), Pd(II), Pt(II), and Pt(IV), and measuring bacterial growth in planktonic assays through increases in optical density. In each experiment, bacterial growth was compared with control cultures of titanates or bacteria alone. We observed no suppression of bacterial growth by the sodium titanates alone, but significant (p < 0.05, two-sided t-tests) suppression was observed with metal-titanate compounds, particularly Au(III)-titanates, but with other metal titanates as well. Growth inhibition ranged from 15 to 100% depending on the metal ion and bacterial species involved. Furthermore, in specific cases, the titanates inhibited bacterial growth 5- to 375-fold versus metal ions alone, suggesting that titanates enhanced metal-bacteria interactions. This work supports further development of metal titanates as a novel class of antibacterials.

  2. Titan's geoid and hydrology: implications for Titan's geological evolution

    Science.gov (United States)

    Sotin, Christophe; Seignovert, Benoit; Lawrence, Kenneth; MacKenzie, Shannon; Barnes, Jason; Brown, Robert

    2014-05-01

    A 1x1 degree altitude map of Titan is constructed from the degree 4 gravity potential [1] and Titan's shape [2] determined by the Radio Science measurements and RADAR observations of the Cassini mission. The amplitude of the latitudinal altitude variations is equal to 300 m compared to 600 m for the amplitude of the latitudinal shape variations. The two polar caps form marked depressions with an abrupt change in topography at exactly 60 degrees at both caps. Three models are envisaged to explain the low altitude of the polar caps: (i) thinner ice crust due to higher heat flux at the poles, (ii) fossil shape acquired if Titan had higher spin rate in the past, and (iii) subsidence of the crust following the formation of a denser layer of clathrates as ethane rain reacts with the H2O ice crust [3]. The later model is favored because of the strong correlation between the location of the cloud system during the winter season and the latitude of the abrupt change in altitude. Low altitude polar caps would be the place where liquids would run to and eventually form large seas. Indeed, the large seas of Titan are found at the deepest locations at the North Pole. However, the lakes and terrains considered to be evaporite candidates due to their spectral characteristics in the infrared [4,5] seem to be perched. Lakes may have been filled during Titan's winter and then slowly evaporated leaving material on the surface. Interestingly, the largest evaporite deposits are located at the equator in a deep depression 150 m below the altitude of the northern seas. This observation seems to rule out the presence of a global subsurface hydrocarbon reservoir unless the evaporation rate at the equator is faster than the transport of fluids from the North Pole to the equator. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Iess L. et al. (2012) Science, doi 10.1126/science.1219631. [2] Lorenz R.D. (2013

  3. Nonthermal atmospheric escape from Mars and Titan

    International Nuclear Information System (INIS)

    Lammer, H.; Bauer, S.J.

    1991-01-01

    Energy flux spectra and particle concentrations of the hot O and N coronae from Mars and Titan, respectively, resulting primarily from dissociative recombination of molecular ions, have been calculated by means of a Monte Carlo method. The calculated energy flux spectra lead to an escape flux null esc ∼ 6 x 10 6 cm -2 s -1 for Mars and null esc ∼ 2 x 10 6 cm -2 s -1 for Titan, corresponding to a mass loss of about 0.14 kg/s for Mars and about 0.3 kg/s for Titan. (The contribution of electron impact ionization on N 2 amounts to only about 25% of Titan's mass loss.) Mass loss via solar and magnetospheric wind is also estimated using newly calculated mass loading limits. The mass loss via ion pickup from the extended hot atom corona for Mars amounts to about 0.25 kg/s (O + ) and for Titan to about 50 g/s (N 2 + or H 2 CN + ). Thus, the total mass loss rate from Mars and Titan is about the same, i.e., 0.4 kg/s

  4. Al2O3 - TiO2-A simple sol-gel strategy to the synthesis of low temperature sintered alumina-aluminium titanate composites through a core-shell approach

    International Nuclear Information System (INIS)

    Jayasankar, M.; Ananthakumar, S.; Mukundan, P.; Wunderlich, W.; Warrier, K.G.K.

    2008-01-01

    A simple sol-gel based core-shell approach for the synthesis of alumina-aluminium titanate composite is reported. Alumina is the core and titania is the shell. The coating of titania has been performed in aqueous medium on alumina particle by means of heterocoagulation of titanyl chloride. Further heat treatment results in low temperature formation of aluminium titanate as well as low temperature sintering of alumina-aluminium titanate composites. The lowering of the reaction temperature can be attributed to the maximisation of the contact surface between the reactants due to the core-shell approach involving nanoparticles. The mechanism of formation of aluminium titanate and the observations on densification features in the present process are compared with that of mixture of oxides under identical conditions. The sintered alumina-aluminium titanate composite has an average grain size of 2 μm. - Graphical abstract: The article presents a simple sol-gel process through core-shell approach to the synthesis of low temperature sintered alumina-aluminium titanate. The lowering of the reaction temperature can be attributed to the maximisation of the contact surface between the reactant due to the core-shell approach. This material showed the better microstructure control compared to the standard solid-state mixing route

  5. A whiff of nebular gas in Titan's atmosphere - Potential implications for the conditions and timing of Titan's formation

    Science.gov (United States)

    Glein, Christopher R.

    2017-09-01

    In situ data from the GCMS instrument on the Huygens probe indicate that Titan's atmosphere contains small amounts of the primordial noble gases 36Ar and 22Ne (tentative detection), but it is unknown how they were obtained by the satellite. Based on the apparent similarity in the 22Ne/36Ar (atom) ratio between Titan's atmosphere and the solar composition, a previously neglected hypothesis for the origin of primordial noble gases in Titan's atmosphere is suggested - these species may have been acquired near the end of Titan's formation, when the moon could have gravitationally captured some nebular gas that would have been present in its formation environment (the Saturnian subnebula). These noble gases may be remnants of a primary atmosphere. This could be considered the simplest hypothesis to explain the 22Ne/36Ar ratio observed at Titan. However, the 22Ne/36Ar ratio may not be exactly solar if these species can be fractionated by external photoevaporation in the solar nebula, atmospheric escape from Titan, or sequestration on the surface of Titan. While the GCMS data are consistent with a 22Ne/36Ar ratio of 0.05 to 2.5 times solar (1σ range), simple estimates that attempt to account for some of the effects of these evolutionary processes suggest a sub-solar ratio, which may be depleted by approximately one order of magnitude. Models based on capture of nebular gas can explain why the GCMS did not detect any other primordial noble gas isotopes, as their predicted abundances are below the detection limits (especially for 84Kr and 132Xe). It is also predicted that atmospheric Xe on Titan should be dominated by radiogenic 129Xe if the source of primordial Xe is nebular gas. Of order 10-2-10-1 bar of primordial H2 may have been captured along with the noble gases from a gas-starved disk, but this H2 would have quickly escaped from the initial atmosphere. To have the opportunity to capture nebular gas, Titan should have formed within ∼10 Myr of the formation of the

  6. Verification of a hybrid adjoint methodology in Titan for single photon emission computed tomography - 316

    International Nuclear Information System (INIS)

    Royston, K.; Haghighat, A.; Yi, C.

    2010-01-01

    The hybrid deterministic transport code TITAN is being applied to a Single Photon Emission Computed Tomography (SPECT) simulation of a myocardial perfusion study. The TITAN code's hybrid methodology allows the use of a discrete ordinates solver in the phantom region and a characteristics method solver in the collimator region. Currently we seek to validate the adjoint methodology in TITAN for this application using a SPECT model that has been created in the MCNP5 Monte Carlo code. The TITAN methodology was examined based on the response of a single voxel detector placed in front of the heart with and without collimation. For the case without collimation, the TITAN response for single voxel-sized detector had a -9.96% difference relative to the MCNP5 response. To simulate collimation, the adjoint source was specified in directions located within the collimator acceptance angle. For a single collimator hole with a diameter matching the voxel dimension, a difference of -0.22% was observed. Comparisons to groupings of smaller collimator holes of two different sizes resulted in relative differences of 0.60% and 0.12%. The number of adjoint source directions within an acceptance angle was increased and showed no significant change in accuracy. Our results indicate that the hybrid adjoint methodology of TITAN yields accurate solutions greater than a factor of two faster than MCNP5. (authors)

  7. Coupled atmosphere-ocean models of Titan's past

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, James B.; Lunine, Jonathan I.; Courtin, Regis

    1993-01-01

    The behavior and possible past evolution of fully coupled atmosphere and ocean model of Titan are investigated. It is found that Titan's surface temperature was about 20 K cooler at 4 Gyr ago and will be about 5 K warmer 0.5 Gyr in the future. The change in solar luminosity and the conversion of oceanic CH4 to C2H6 drive the evolution of the ocean and atmosphere over time. Titan appears to have experienced a frozen epoch about 3 Gyr ago independent of whether an ocean is present or not. This finding may have important implications for understanding the inventory of Titan's volatile compounds.

  8. History of the Development of Liquid-Applied Coatings for Protection of Reinforced Concrete

    Science.gov (United States)

    Curran, Joseph J.; Hansen, marlin H.

    2005-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem for structures at Kennedy Space Center (KSC). KSC is located on the coast of Florida in a highly corrosive atmosphere. Launch pads, highway bridge infrastructure, and buildings are strongly affected. To mitigate these problems, NASA initiated a development program for a Galvanic Liquid-Applied Coating System (GLACS). A breakthrough in this area would have great commercial value in transportation, marine and construction industry infrastructures. The patented NASA GLACS system has undergone considerable testing to meet the needs of commercialization. A moisture-cure coating gives excellent adhesion with ease of application compared to existing galvanic products on the market. The latest development, GalvaCori; can be sprayed or hand applied to almost any structure shape. A self-adhesive conductive tape system has been devised to simplify current collection within the coating areas. In testing programs, millivolt potential and milliamp output per square foot of anode have been closely studied at actual test sites. These two parameters are probably the most challenging items of a resin-based, room-temperature-applied, galvanic coating. Extensive re-formulation has resulted in a system that provides the needed polarization for catholic protection of reinforcing steel in concrete in a variety of structure environments. The rate of corrosion of rebar in concrete is greatly affected by the environment of the structure. In addition to this, for any given concrete structure; moisture level, carbonization, and chloride contamination influences the rate of rebar corrosion. Similarly, the cathodic protection level of galvanic systems is also dependent on the moisture level of the concrete. GalvaCorr is formulated to maintain galvanic activity as the moisture level of the structure declines. GalvaCorr is available as a three-part kit. The mixing step requires about ten minutes. The viscosity can be easily

  9. Titan atmospheric composition by hypervelocity shock layer analysis

    International Nuclear Information System (INIS)

    Nelson, H.F.; Park, C.; Whiting, E.E.

    1989-01-01

    The Cassini Mission, a NASA/ESA cooperative project which includes a deployment of probe into the atmosphere of Titan, is described, with particular attention given to the shock radiometer experiment planned for the Titan probe for the analysis of Titan's atmosphere. Results from a shock layer analysis are presented, demonstrating that the mole fractions of the major species (N2, CH4, and, possibly Ar) in the Titan atmosphere can be successfully determined by the Titan-probe radiometer, by measuring the intensity of the CN(violet) radiation emitted in the shock layer during the high velocity portion of the probe entry between 200 and 400 km altitude. It is shown that the sensitivity of the CN(violet) radiation makes it possible to determine the mole fractions of N2, CH4, and Ar to about 0.015, 0.003, and 0.01, respectively, i.e., much better than the present uncertainties in the composition of Titan atmosphere. 29 refs

  10. METHOD OF APPLYING NICKEL COATINGS ON URANIUM

    Science.gov (United States)

    Gray, A.G.

    1959-07-14

    A method is presented for protectively coating uranium which comprises etching the uranium in an aqueous etching solution containing chloride ions, electroplating a coating of nickel on the etched uranium and heating the nickel plated uranium by immersion thereof in a molten bath composed of a material selected from the group consisting of sodium chloride, potassium chloride, lithium chloride, and mixtures thereof, maintained at a temperature of between 700 and 800 deg C, for a time sufficient to alloy the nickel and uranium and form an integral protective coating of corrosion-resistant uranium-nickel alloy.

  11. Summary report of Japan-US joint project (TITAN). FuY 2007-2012

    International Nuclear Information System (INIS)

    Okuno, K.; Muroga, T.

    2014-01-01

    This report summarizes the scientific accomplishments achieved through the TITAN Japan-US Collaboration Program. The TITAN collaboration (Tritium, Irradiation and Thermofluid for America and Nippon) has been carried out through six years (FuY 2007-2012) under the collaboration implemented by establishing Annex I to the NIFS-ORNL Agreement on Academic and Scientific Exchange. The TITAN collaboration was established to obtain fundamental understanding for the control of tritium and thermofluid in first wall, blanket and recovery systems with particular emphasis on their interfacial issues. The experiments were designed for testing under conditions specific to fusion, such as intense irradiation, high heat/particle flux, and circulation in a high magnetic field. The results have been applied using integrated modeling to advance the design of tritium and heat control in MFE and IFE systems. This issue is the collection of 34 papers presented at the entitled meeting. All the 34 of the presented papers are indexed individually. (J.P.N.)

  12. Ceria and strontium titanate based electrodes

    DEFF Research Database (Denmark)

    2010-01-01

    A ceramic anode structure obtainable by a process comprising the steps of: (a) providing a slurry by dispersing a powder of an electronically conductive phase and by adding a binder to the dispersion, in which said powder is selected from the group consisting of niobium-doped strontium titanate......, vanadium-doped strontium titanate, tantalum-doped strontium titanate, and mixtures thereof, (b) sintering the slurry of step (a), (c) providing a precursor solution of ceria, said solution containing a solvent and a surfactant, (d) impregnating the resulting sintered structure of step (b...

  13. Anion and cation diffusion in barium titanate and strontium titanate

    International Nuclear Information System (INIS)

    Kessel, Markus Franz

    2012-01-01

    Perovskite oxides show various interesting properties providing several technical applications. In many cases the defect chemistry is the key to understand and influence the material's properties. In this work the defect chemistry of barium titanate and strontium titanate is analysed by anion and cation diffusion experiments and subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS). The reoxidation equation for barium titanate used in multi-layer ceramic capacitors (MLCCs) is found out by a combination of different isotope exchange experiments and the analysis of the resulting tracer diffusion profiles. It is shown that the incorporation of oxygen from water vapour is faster by orders of magnitude than from molecular oxygen. Chemical analysis shows the samples contain various dopants leading to a complex defect chemistry. Dysprosium is the most important dopant, acting partially as a donor and partially as an acceptor in this effectively acceptor-doped material. TEM and EELS analysis show the inhomogeneous distribution of Dy in a core-shell microstructure. The oxygen partial pressure and temperature dependence of the oxygen tracer diffusion coefficients is analysed and explained by the complex defect chemistry of Dy-doped barium titanate. Additional fast diffusion profiles are attributed to fast diffusion along grain boundaries. In addition to the barium titanate ceramics from an important technical application, oxygen diffusion in cubic, nominally undoped BaTiO 3 single crystals has been studied by means of 18 O 2 / 16 O 2 isotope exchange annealing and subsequent determination of the isotope profiles in the solid by ToF-SIMS. It is shown that a correct description of the diffusion profiles requires the analysis of the diffusion through the surface space-charge into the material's bulk. Surface exchange coefficients, space-charge potentials and bulk diffusion coefficients are analysed as a function of oxygen partial pressure and temperature. The

  14. Lead titanate nanotubes synthesized via ion-exchange method: Characteristics and formation mechanism

    International Nuclear Information System (INIS)

    Song Liang; Cao Lixin; Li Jingyu; Liu Wei; Zhang Fen; Zhu Lin; Su Ge

    2011-01-01

    Highlights: → Lead titanate nanotubes PbTi 3 O 7 were firstly synthesized by ion-exchange method. → Sodium titanate nanotubes have ion exchangeability. → Lead titanate nanotubes show a distinct red shift on absorption edge. - Abstract: A two-step method is presented for the synthesis of one dimensional lead titanate (PbTi 3 O 7 ) nanotubes. Firstly, titanate nanotubes were prepared by an alkaline hydrothermal process with TiO 2 nanopowder as precursor, and then lead titanate nanotubes were formed through an ion-exchange reaction. We found that sodium titanate nanotubes have ion exchangeability with lead ions, while protonated titanate nanotubes have not. For the first time, we distinguished the difference between sodium titanate nanotubes and protonated titanate nanotubes in the ion-exchange process, which reveals a layer space effect of nanotubes in the ion-exchange reaction. In comparison with sodium titanate, the synthesized lead titanate nanotubes show a narrowed bandgap.

  15. Titan's methane clock

    Science.gov (United States)

    Nixon, C. A.; Jennings, D. E.; Romani, P. N.; Teanby, N. A.; Irwin, P. G. J.; Flasar, F. M.

    2010-04-01

    Measurements of the 12C/13C and D/H isotopic ratios in Titan's methane show intriguing differences from the values recorded in the giant planets. This implies that either (1) the atmosphere was differently endowed with material at the time of formation, or (2) evolutionary processes are at work in the moon's atmosphere - or some combination of the two. The Huygens Gas Chromatograph Mass Spectrometer Instrument (GCMS) found 12CH4/13CH4 = 82 +/- 1 (Niemann et al. 2005), some 7% lower than the giant planets' value of 88 +/- 7 (Sada et al. 1996), which closely matches the terrestrial inorganic standard of 89. The Cassini Composite Infrared Spectrometer (CIRS) has previously reported 12CH4/13CH4 of 77 +/-3 based on nadir sounding, which we now revise upwards to 80 +/- 4 based on more accurate limb sounding. The CIRS and GCMS results are therefore in agreement about an overall enrichment in 13CH4 of ~10%. The value of D/H in Titan's CH4 has long been controversial: historical measurements have ranged from about 8-15 x 10-5 (e.g. Coustenis et al. 1989, Coustenis et al. 2003). A recent measurement based on CIRS limb data by Bezard et al. (2007) puts the D/H in CH4 at (13 +/- 1) x 10-5, very much greater than in Jupiter and Saturn, ~2 x 10-5 (Mahaffy et al. 1998, Fletcher et al. 2009). To add complexity, the 12C/13C and D/H vary among molecules in Titan atmosphere, typically showing enhancement in D but depletion in 13C in the daughter species (H2, C2H2, C2H6), relative to the photochemical progenitor, methane. Jennings et al. (2009) have sought to interpret the variance in carbon isotopes as a Kinetic Isotope Effect (KIE), whilst an explanation for the D/H in all molecules remains elusive (Cordier et al. 2008). In this presentation we argue that evolution of isotopic ratios in Titan's methane over time forms a ticking 'clock', somewhat analogous to isotopic ratios in geochronology. Under plausible assumptions about the initial values and subsequent replenishment, various

  16. Ferroelectric and Piezoelectric properties of (111) oriented lanthanum modified lead zirconate titanate film

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Soma, E-mail: som@nal.res.in; Antony Jeyaseelan, A.; Sruthi, S.

    2014-07-01

    Lanthanum modified lead zirconate titanate (PLZT) thick film with molecular formula of Pb{sub 0.92}La{sub 0.08}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.98}O{sub 3} was grown preferentially along (111) direction on Pt/SiO{sub 2}/Si (platinum/silicon oxide/silicon) substrate by spin coating of chemical solution. The directional growth of the film was facilitated by platinum (Pt) (111) template and rapid thermal annealing. X-ray diffraction pattern and atomic force microscopy revealed the preferential growth of the PLZT film. The film was characterized for ferroelectric and detailed piezoelectric properties in a parallel plate capacitor (metal–PLZT–metal) configuration. Ferroelectric characterization of the film showed saturated hysteresis loop with remanent polarization and coercive electric field values of 10.14 μC/cm{sup 2} and 42 kV/cm, respectively, at an applied field of 300 kV/cm. Longitudinal piezoelectric coefficient (d{sub 33,f}) was measured by employing converse piezoelectric effect where electrical charge response and displacement were measured with electrical voltage excitation on the sample electrodes. The effective transverse piezoelectric coefficient (e{sub 31,f}) was derived from charge measurement with an applied mechanical excitation strain by using the four point bending method. d{sub 33,f} and e{sub 31,f} coefficients of PLZT films were found to be 380 pm/V and − 0.831 C/m{sup 2} respectively. - Highlights: • PLZT (111) film is prepared by spin coating of chemical sol on Pt (111) template. • Piezoelectric d{sub 33} value (380 pm/V) of PLZT film is found 20% higher than PZT. • Transverse piezocoefficient e{sub 31,f} of PLZT film is reported for the first time.

  17. Titan Submarine : AUV Design for Cryogenic Extraterrestrial Seas of Hydrocarbons

    Science.gov (United States)

    Lorenz, Ralph D.; Oleson, Steven; Colozza, Tony; Hartwig, Jason; Schmitz, Paul; Landis, Geoff; Paul, Michael; Walsh, Justin

    2016-04-01

    to date, which brought together power/propulsion/space systems expertise from NASA Glenn Research Center, with hydrodynamics, propulsion and operations from the Penn State Applied Research Lab, and the latest Titan understanding from the JHU Applied Physics Lab.

  18. Titan Orbiter Aerorover Mission with Enceladus Science (TOAMES)

    Science.gov (United States)

    Sittler, E.; Cooper, J.; Mahaffy, P.; Fairbrother, D.; de Pater, I.; Schulze-Makuch, D.; Pitman, J.

    2007-08-01

    same time made us aware of how little we understand about these bodies. For example, the source, and/or recycling mechanism, of methane in Titan's atmosphere is still puzzling. Indeed, river beds (mostly dry) and lakes have been spotted, and occasional clouds have been seen, but the physics to explain the observations is still mostly lacking, since our "image" of Titan is still sketchy and quite incomplete. Enceladus, only 500 km in extent, is even more puzzling, with its fiery plumes of vapor, dust and ice emanating from its south polar region, "feeding" Saturn's E ring. Long term variability of magnetospheric plasma, neutral gas, E-ring ice grain density, radio emissions, and corotation of Saturn's planetary magnetic field in response to Enceladus plume activity are of great interest for Saturn system science. Both Titan and Enceladus are bodies of considerable astrobiological interest in view of high organic abundances at Titan and potential subsurface liquid water at Enceladus. We propose to develop a new mission to Titan and Enceladus, the Titan Orbiter Aerorover Mission with Enceladus Science (TOAMES), to address these questions using novel new technologies. TOAMES is a multi-faceted mission that starts with orbit insertion around Saturn using aerobraking with Titan's extended atmosphere. We then have an orbital tour around Saturn (for 1-2 years) and close encounters with Enceladus, before it goes into orbit around Titan (via aerocapture). During the early reconnaissance phase around Titan, perhaps 6 months long, the orbiter will use altimetry, radio science and remote sensing instruments to measure Titan's global topography, subsurface structure and atmospheric winds. This information will be used to determine where and when to release the Aerorover, so that it can navigate safely around Titan and identify prime sites for surface sampling and analysis. In situ instruments will sample the upper atmosphere which may provide the seed population for the complex

  19. Spacecraft Exploration of Titan and Enceladus

    Science.gov (United States)

    Matson, D.; Coustenis, A.; Lunine, J. I.; Lebreton, J.; Reh, K.; Beauchamp, P.; Erd, C.

    2009-12-01

    The future exploration of Titan and Enceladus is very important for planetary science. The study titled Titan Saturn System Mission (TSSM) led to an announcement in which ESA and NASA prioritized future OPF missions, stating that TSSM is planned after EJSM (for details see http://www.lpi.usra.edu/opag/). The TSSM concept consists of an Orbiter that would carry two in situ elements: the Titan Montgolfiere hot air balloon and the Titan Lake Lander. This mission could launch in the 2023-2025 timeframe on a trajectory to arrive ~9 years later and begin a 4-year mission in the Saturnian system. At an appropriate time after arrival at Saturn, the montgolfiere would be delivered to Titan to begin its mission of airborne, scientific observations of Titan from an altitude of about 10 km above the surface. The montgolfiere would have a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) power system whose waste heat would warm the gas in the balloon, providing buoyancy. It would be designed to survive at least 6-12 months in Titan’s atmosphere. With the predicted winds and weather, it should be possible to circumnavigate the globe! Later, on a subsequent fly-by, the TSSM orbiter would send the Lake Lander to Titan. It would descend through the atmosphere making scientific measurements, much like Huygens did, and then land and float on one of Titan’s seas. This would be its oceanographic phase of making a physical and chemical assessment of the sea. The Lake Lander would operate for 8-10 hours until its batteries become depleted. Following the delivery of the in situ elements, the TSSM orbiter would then explore the Saturn system for two years on a tour that includes in situ sampling of Enceladus’ plumes as well as flybys of Titan. After the Saturn tour, the TSSM orbiter would go into orbit around Titan and carry out a global survey phase. Synergistic observations would be carried out by the TSSM orbiter and the in situ elements. The scientific requirements for

  20. Superamphiphobic Surfaces Prepared by Coating Multifunctional Nanofluids.

    Science.gov (United States)

    Esmaeilzadeh, Pouriya; Sadeghi, Mohammad Taghi; Bahramian, Alireza; Fakhroueian, Zahra; Zarbakhsh, Ali

    2016-11-23

    Construction of surfaces with the capability of repelling both water and oil is a challenging issue. We report the superamphiphobic properties of mineral surfaces coated with nanofluids based on synthesized Co-doped and Ce-doped Barium Strontium Titanate (CoBST and CeBST) nanoparticles and fluorochemicals of trichloro(1H,1H,2H,2H-perfluorooctyl)silane (PFOS) and polytetrafluoroethylene (PTFE). Coating surfaces with these nanofluids provides both oil (with surface tensions as low as 23 mN/m) and water repellency. Liquids with high surface tension (such as water and ethylene glycol) roll off the coated surface without tilting. A water drop released from 8 mm above the coated surface undergoes first a lateral displacement from its trajectory and shape deformation, striking the surface after 23 ms, bouncing and rolling off freely. These multifunctional coating nanofluids impart properties of self-cleaning. Applications include coating surfaces where cleanliness is paramount such as in hospitals and domestic environments as well as the maintenance of building facades and protection of public monuments from weathering. These superamphiphobic-doped nanofluids have thermal stability up to 180 °C; novel industrial applications include within fracking and the elimination of condensate blockage in gas reservoirs.

  1. Titan Montgolfiere Terrestrial Test Bed, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — With the Titan Saturn System Mission, NASA is proposing to send a Montgolfiere balloon to probe the atmosphere of Titan. To better plan this mission and create a...

  2. Titan Montgolfiere Terrestrial Test Bed, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — With the Titan Saturn System Mission, NASA is proposing to send a Montgolfiere balloon to probe the atmosphere of Titan. In order to better plan this mission and...

  3. AVIATR—Aerial Vehicle for In-situ and Airborne Titan Reconnaissance

    DEFF Research Database (Denmark)

    Barnes, Jason W.; Lemke, Lawrence; Foch, Rick

    2012-01-01

    We describe a mission concept for a stand-alone Titan airplane mission: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR). With independent delivery and direct-to-Earth communications, AVIATR could contribute to Titan science either alone or as part of a sustained Titan...... Exploration Program. As a focused mission, AVIATR as we have envisioned it would concentrate on the science that an airplane can do best: exploration of Titan's global diversity. We focus on surface geology/hydrology and lower-atmospheric structure and dynamics. With a carefully chosen set of seven...... of a Space Vehicle (SV) for cruise, an Entry Vehicle (EV) for entry and descent, and the Air Vehicle (AV) to fly in Titan's atmosphere. Using an Earth-Jupiter gravity assist trajectory delivers the spacecraft to Titan in 7.5 years, after which the AVIATR AV would operate for a 1-Earth-year nominal mission...

  4. HST observations of the limb polarization of Titan

    Science.gov (United States)

    Bazzon, A.; Schmid, H. M.; Buenzli, E.

    2014-12-01

    Context. Titan is an excellent test case for detailed studies of the scattering polarization from thick hazy atmospheres. Accurate scattering and polarization parameters have been provided by the in situ measurements of the Cassini-Huygens landing probe. For Earth-bound observations Titan can only be observed at a backscattering situation, where the disk-integrated polarization is close to zero. However, with resolved imaging polarimetry a second order polarization signal along the entire limb of Titan can be measured. Aims: We present the first limb polarization measurements of Titan, which are compared as a test to our limb polarization models. Methods: Previously unpublished imaging polarimetry from the HST archive is presented, which resolves the disk of Titan. We determine flux-weighted averages of the limb polarization and radial limb polarization profiles, and investigate the degradation and cancelation effects in the polarization signal due to the limited spatial resolution of our observations. Taking this into account we derive corrected values for the limb polarization in Titan. The results are compared with limb polarization models, using atmosphere and haze scattering parameters from the literature. Results: In the wavelength bands between 250 nm and 2 μm a strong limb polarization of about 2 - 7% is detected with a position angle perpendicular to the limb. The fractional polarization is highest around 1 μm. As a first approximation, the polarization seems to be equally strong along the entire limb. The comparison of our data with model calculations and the literature shows that the detected polarization is compatible with expectations from previous polarimetric observations taken with Voyager 2, Pioneer 11, and the Huygens probe. Conclusions: Our results indicate that ground-based monitoring measurements of the limb-polarization of Titan could be useful for investigating local haze properties and the impact of short-term and seasonal variations of

  5. Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

    Science.gov (United States)

    Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

    2002-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

  6. Experimental basis for a Titan probe organic analysis

    International Nuclear Information System (INIS)

    Mckay, C.P.; Scattergood, T.W.; Borucki, W.J.; Kasting, J.F.; Miller, S.L.; California Univ., San Diego, La Jolla)

    1986-01-01

    The recent Voyager flyby of Titan produced evidence for at least nine organic compounds in that atmosphere that are heavier than methane. Several models of Titan's atmosphere, as well as laboratory simulations, suggest the presence of organics considerably more complex that those observed. To ensure that the in situ measurements are definitive with respect to Titan's atmosphere, experiment concepts, and the related instrumentation, must be carefully developed specifically for such a mission. To this end, the possible composition of the environment to be analyzed must be bracketed and model samples must be provided for instrumentation development studies. Laboratory studies to define the optimum flight experiment and sampling strategy for a Titan entry probe are currently being conducted. Titan mixtures are being subjected to a variety of energy sources including high voltage electron from a DC discharge, high current electric shock, and laser detonation. Gaseous and solid products are produced which are then analyzed. Samples from these experiements are also provided to candidate flight experiments as models for instrument development studies. Preliminary results show that existing theoretical models for chemistry in Titan's atmosphere cannot adequetely explain the presence and abundance of all trace gases observed in these experiments

  7. Thermal Annealing Effect on Optical Properties of Binary TiO2-SiO2 Sol-Gel Coatings

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2012-12-01

    Full Text Available TiO2-SiO2 binary coatings were deposited by a sol-gel dip-coating method using tetrabutyl titanate and tetraethyl orthosilicate as precursors. The structure and chemical composition of the coatings annealed at different temperatures were analyzed by Raman spectroscopy and Fourier Transform Infrared (FTIR spectroscopy. The refractive indices of the coatings were calculated from the measured transmittance and reflectance spectra. An increase in refractive index with the high temperature thermal annealing process was observed. The Raman and FTIR results indicate that the refractive index variation is due to changes in the removal of the organic component, phase separation and the crystal structure of the binary coatings.

  8. A new method for the preparation of strontium titanate and strontium hypovanadate

    International Nuclear Information System (INIS)

    Balasubramanian, M.R.

    1985-01-01

    Strontium titanate has been a prized chemical by virtue of its dielectric, photoelectric and surface properties. The compound crystallises with the cubic perovskite structure. Till now only two techniques (and a few variants therein) have been employed for its synthesis, one of them is a solid state reaction between SrCO 3 and TiO 2 at 1100deg, and the other is a coprecipitation of strontium titanyl oxalate followed by calcination at 850deg. As ternary oxides, such as copper chromite, have been prepared by complex formation, the author found it interesting to apply this method to the preparation of strontium titanate. The most easily accessible and versatile complexing agent, EDTA, was used. (author)

  9. History and challenges of barium titanate: Part I

    Directory of Open Access Journals (Sweden)

    Vijatović M.M.

    2008-01-01

    Full Text Available Barium titanate is the first ferroelectric ceramics and a good candidate for a variety of applications due to its excellent dielectric, ferroelectric and piezoelectric properties. Barium titanate is a member of a large family of compounds with the general formula ABO3 called perovskites. Barium titanate can be prepared using different methods. The synthesis method depends on the desired characteristics for the end application. The used method has a significant influence on the structure and properties of barium titanate materials. In this review paper, Part I contains a study of the BaTiO3 structure and frequently used synthesis methods.

  10. Titan's organic chemistry: Results of simulation experiments

    Science.gov (United States)

    Sagan, Carl; Thompson, W. Reid; Khare, Bishun N.

    1992-01-01

    Recent low pressure continuous low plasma discharge simulations of the auroral electron driven organic chemistry in Titan's mesosphere are reviewed. These simulations yielded results in good accord with Voyager observations of gas phase organic species. Optical constants of the brownish solid tholins produced in similar experiments are in good accord with Voyager observations of the Titan haze. Titan tholins are rich in prebiotic organic constituents; the Huygens entry probe may shed light on some of the processes that led to the origin of life on Earth.

  11. The commercial evolution of the Titan program

    Science.gov (United States)

    Isakowitz, Steven

    1988-07-01

    The present status evaluation of proprietary efforts to turn the once exclusively government-requirements-oriented Titan launch vehicle into a successful commercial competitor is divided into three phases. The first phase notes recent changes in U.S. space transportation policy and the Titan configurations evaluated for commercial feasibility. The second phase is a development history for the current vehicle's marketing organization and the right-to-use agreement for a launch site. Phase three projects the prospective marketing climate for a commercial Titan vehicle and its planned improvements.

  12. Selections from 2017: Discoveries in Titan's Atmosphere

    Science.gov (United States)

    Kohler, Susanna

    2017-12-01

    Editors note:In these last two weeks of 2017, well be looking at a few selections that we havent yet discussed on AAS Nova from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume in January.Carbon Chain Anions and the Growth of Complex Organic Molecules in Titans IonospherePublished July2017Main takeaway:Graphic depicting some of the chemical reactions taking place in Titans atmosphere, leading to the generation of organic haze particles. [ESA]In a recently published study led by Ravi Desai (University College London), scientists used data from the Cassini mission to identify negatively charged molecules known as carbon chain anions in the atmosphere of Saturns largest moon, Titan.Why its interesting:Carbon chain anions are the building blocks ofmore complex molecules, and Titans thick nitrogen and methane atmosphere mightmimic the atmosphere of earlyEarth. This first unambiguous detection of carbon chain anions in a planet-like atmosphere might therefore teach us about the conditions and chemical reactions that eventually led to the development of life on Earth. And ifwe can use Titan to learn about how complex molecules grow from these anion chains, we may be able to identify auniversal pathway towards the ingredients for life.What weve learned so far:Cassini measured fewer and fewer lower-mass anions the deeper in Titans ionosphere that it looked and at the same time,an increase in the number of precursors to larger aerosol molecules further down. This tradeoff strongly suggests that the anions are indeed involved in building up the more complex molecules, seeding their eventual growth into the complex organic haze of Titans lower atmosphere.CitationR. T. Desai et al 2017 ApJL 844 L18. doi:10.3847/2041-8213/aa7851

  13. Niobium-doped strontium titanates as SOFC anodes

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L. Reine

    2008-01-01

    been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

  14. Volatile products controlling Titan's tholins production

    KAUST Repository

    Carrasco, Nathalie

    2012-05-01

    A quantitative agreement between nitrile relative abundances and Titan\\'s atmospheric composition was recently shown with a reactor simulating the global chemistry occurring in Titan\\'s atmosphere (Gautier et al. [2011]. Icarus, 213, 625-635). Here we present a complementary study on the same reactor using an in situ diagnostic of the gas phase composition. Various initial N 2/CH 4 gas mixtures (methane varying from 1% to 10%) are studied, with a monitoring of the methane consumption and of the stable gas neutrals by in situ mass spectrometry. Atomic hydrogen is also measured by optical emission spectroscopy. A positive correlation is found between atomic hydrogen abundance and the inhibition function for aerosol production. This confirms the suspected role of hydrogen as an inhibitor of heterogeneous organic growth processes, as found in Sciamma-O\\'Brien et al. (Sciamma-O\\'Brien et al. [2010]. Icarus, 209, 704-714). The study of the gas phase organic products is focussed on its evolution with the initial methane amount [CH 4] 0 and its comparison with the aerosol production efficiency. We identify a change in the stationary gas phase composition for intermediate methane amounts: below [CH 4] 0=5%, the gas phase composition is mainly dominated by nitrogen-containing species, whereas hydrocarbons are massively produced for [CH 4] 0>5%. This predominance of N-containing species at lower initial methane amount, compared with the maximum gas-to solid conversion observed in Sciamma-O\\'Brien et al. (2010) for identical methane amounts confirms the central role played by N-containing gas-phase compounds to produce tholins. Moreover, two protonated imines (methanimine CH 2NH and ethanamine CH 3CHNH) are detected in the ion composition in agreement with Titan\\'s INMS measurements, and reinforcing the suspected role of these chemical species on aerosol production. © 2012 Elsevier Inc.

  15. Selective adsorption and ion exchange of metal cations and anions with silico-titanates and layered titanates

    International Nuclear Information System (INIS)

    Anthony, R.G.; Philip, C.V.

    1993-01-01

    Metal ions may be removed from aqueous wastes from metal processing plants and from refineries. They may also be used in concentrating radioactive elements found in dilute, aqueous, nuclear wastes. A new series of silico-titanates and alkali titanates are shown to have specific selectivity for cations of lead, mercury, and cadmium and the dichromate anion in solutions with low and high pH. Furthermore, one particular silico-titanate, TAM-5, was found to be highly selective for Cs + and Sr 2+ in solutions of 5.7 M Na + and 0.6 M Oh - . A high potential exists for these materials for removing Cs + and Sr 2+ from radioactive aqueous wastes containing high concentrations of Na + at high and low pH

  16. Radiation effects in uranium-niobium titanates

    International Nuclear Information System (INIS)

    Lian, J.; Wang, S.X.; Wang, L.M.; Ewing, R.C.

    2000-01-01

    Pyrochlore is an important actinide host phase proposed for the immobilization of high level nuclear wastes and excess weapon plutonium.[1] Synthetic pyrochlore has a great variety of chemical compositions due to the possibility of extensive substitutions in the pyrochlore structure.[2] During the synthesis of pyrochlore, additional complex titanate phases may form in small quantities. The response of these phases to radiation damage must be evaluated because volume expansion of minor phases may cause micro-fracturing. In this work, two complex uranium-niobium titanates, U 3 NbO 9.8 (U-rich titanate) and Nb 3 UO 10 (Nb-rich titanate) were synthesized by the alkoxide/nitrate route at 1300 deg. C under an argon atmosphere. The phase composition and structure were analyzed by EDS, BSE, XRD, EMPA and TEM techniques. An 800 KeVKr 2+ irradiation was performed using the IVEM-Tandem Facility at Argonne National Laboratory in a temperature range from 30 K to 973 K. The radiation effects were observed by in situ TEM

  17. The TITAN Reversed-Field Pinch fusion reactor study

    International Nuclear Information System (INIS)

    1988-03-01

    The TITAN Reversed-Field Pinch (RFP) fusion reactor study is a multi-institutional research effort to determine the technical feasibility and key developmental issues of an RFP fusion reactor, especially at high power density, and to determine the potential economics, operations, safety, and environmental features of high-mass-power-density fusion systems. The TITAN conceptual designs are DT burning, 1000 MWe power reactors based on the RFP confinement concept. The designs are compact, have a high neutron wall loading of 18 MW/m 2 and a mass power density of 700 kWe/tonne. The inherent characteristics of the RFP confinement concept make fusion reactors with such a high mass power density possible. Two different detailed designs have emerged: the TITAN-I lithium-vanadium design, incorporating the integrated-blanket-coil concept; and the TITAN-II aqueous loop-in-pool design with ferritic steel structure. This report contains a collection of 16 papers on the results of the TITAN study which were presented at the International Symposium on Fusion Nuclear Technology. This collection describes the TITAN research effort, and specifically the TITAN-I and TITAN-II designs, summarizing the major results, the key technical issues, and the central conclusions and recommendations. Overall, the basic conclusions are that high-mass power-density fusion reactors appear to be technically feasible even with neutron wall loadings up to 20 MW/m 2 ; that single-piece maintenance of the FPC is possible and advantageous; that the economics of the reactor is enhanced by its compactness; and the safety and environmental features need not to be sacrificed in high-power-density designs. The fact that two design approaches have emerged, and others may also be possible, in some sense indicates the robustness of the general findings

  18. an oxalate-peroxide complex used in the preparation of doped barium titanate

    NARCIS (Netherlands)

    van der Gijp, S.; Winnubst, Aloysius J.A.; Verweij, H.

    1998-01-01

    A method is described for the preparation of homogeneously doped barium titanate, which can be applied in non-linear dielectric elements. Ba and Ti salts are dissolved, mixed with hydrogen peroxide and added to a solution of ammonium oxalate, resulting in the formation of an insoluble peroxo-oxalate

  19. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Xie Yi

    2009-01-01

    Full Text Available Abstract A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs is presented. Anatase TiO2 nanoparticles (NPs with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

  20. Life cycle assessment for spray coatings applied to the heating tubes of PFBC boiler; Kaatsu ryudoso boiler sonai kan e tekiyosareru yosha coating no life cycle assessment (LCA hyoka)

    Energy Technology Data Exchange (ETDEWEB)

    Sonoya, K; Kihara, S [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1996-12-25

    LCA (Life cycle assessment) is a systematic process used to calculate and evaluate the environmental impacts of products. Because boiler components are now exposed a more severe erosion/corrosion environment by, improving efficiency of thermal power plant, it is expected that the use of thermal spray coatings will increase. The LCA method was attempted to apply to various thermal spray coatings for PFBC (Pressurized Fluidized Bed Combustion) and evaluate the eco-friendly, coatings. The result was gained that all the alumina coatings have good characteristics. In fact the Al2O3-40%ZrO2 coating by APS has the lowest environmental impact and the best erosion resistance, it may be considered the most effective coating. 4 refs., 12 figs., 1 tab.

  1. Advances in Architectural Elements For Future Missions to Titan

    Science.gov (United States)

    Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

    2010-05-01

    The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Recent Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiere hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit into NASA New Frontiers or ESA Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, a clear blueprint has been laid out for the work needed to reduce the risks inherent in such missions and the areas where advances would be beneficial for elements critical to future Titan missions have been identified. The purpose of this paper is to provide a brief overview of the flagship mission architecture and

  2. Cosmic-rays induced Titan tholins and their astrobiological significances

    Science.gov (United States)

    Kobayashi, Kensei; Taniuchi, Toshinori; Hosogai, Tomohiro; Kaneko, Takeo; Takano, Yoshinori; Khare, Bishun; McKay, Chris

    Titan is the largest satellite of Saturn. It is quite unique satellite since it has a dense atmosphere composed of nitrogen and methane, and has been sometimes considered as a model of primitive Earth. In Titan atmosphere, a wide variety of organic compounds and mists made of complex organics. Such solid complex organics are often referred to as tholins. A number of laboratory experiments simulating reactions in Titan atmosphere have been conducted. In most of them, ultraviolet light and discharges (simulating actions of electrons in Saturn magnetosphere) were used, which were simulation of the reactions in upper dilute atmosphere of Titan. We examined possible formation of organic compounds in the lower dense atmosphere of Titan, where cosmic rays are major energies. A Mixture of 35 Torr of methane and 665 Torr of nitrogen was irradiated with high-energy protons (3 MeV) from a van de Graaff accelerator (TIT, Japan) or from a Tandem accelerator (TIARA, QUBS, JAEA, Japan). In some experiments, 13 C-labelled methane was used. We also performed plasma discharges in a mixture of methane (10 %) and nitrogen (90 %) to simulate the reactions in the upper atmosphere of Titan. Solid products by proton irradiation and those by plasma discharges are hereafter referred to as PI-tholins and PD-tholins, respectively. The resulting PI-tholins were observed with SEM and AFM. They were characterized by pyrolysis-GC/MS, gel permeation chromatography, FT-IR, etc. Amino acids in PI-and PD-tholins were analyzed by HPLC, GC/MS and MALDI-TOF-MS after acid hydrolysis. 18 O-Labelled water was used in some cases during hydrolysis. Filamentary and/or globular-like structures were observed by SEM and AFM. By pyrolysis-GC/MS of PI-tholins, ammonia and hydrogen cyanide were detected, which was the same as the results obtained in Titan atmosphere during the Huygens mission. A wide variety of amino acids were detected after hydrolysis of both tholins. It was proved that oxygen atoms in the amino

  3. Color stability of esthetic coatings applied to nickel-titanium archwires

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do REGO

    Full Text Available Abstract Introduction Color stability is an important feature to be considered when using esthetic coated archwires. Objective To evaluate color changes on the surface of esthetic nickel-titanium archwires coated with Teflon (Ortho Organizers, USA or epoxy resin (Tecnident, Brazil after immersion in staining solution. Material and method Twelve 20-mm-long wire segments were used for each type of coating, which were mounted as two test specimens with a width of 7 mm each. The buccal surface of the archwires was evaluated for fluorescence and color measurements both at baseline and after immersion in a staining solution for 21 days using the VITA Easyshade® Compact spectrophotometer (Model DEASYC220. Differences in total color change according to coating type were compared using an independent samples t-test (p<0.05. The surface characteristics of as-received coated archwires were assessed using scanning electron microscopy. Result Color changes were observed on the esthetic coatings, with a significant difference between the two brands analyzed. Surface analysis revealed flaws such as wear, pitting, elevations, lack of material, granulation, grooves, cracks, and lack of standardization in the coating process in all as-received archwires, but flaws were less evident in epoxy-resin coatings. Conclusion The two esthetic coatings did not show color stability, but Teflon coatings showed a more intense color change than epoxy-resin coatings.

  4. A plasmonic modulator based on metal-insulator-metal waveguide with barium titanate core

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Lavrinenko, Andrei

    2013-01-01

    We design a plasmonic modulator which can be utilized as a compact active device in photonic integrated circuits. The active material, barium titanate (BaTiO3), is sandwiched between metal plates and changes its refractive index under applied voltage. Some degree of switching of ferroelectric...

  5. Obtention of polyester-montmorillonite (MMT) nanocomposites applied to powder coating - part 1: nanocomposites characterization

    International Nuclear Information System (INIS)

    Piazza, Diego; Zattera, Ademir J.; Silveira, Debora S.; Lorandi, Natalia P.; Birriel, Eliena J.; Scienza, Lisete C.

    2009-01-01

    The development and obtention of polymeric nanocomposites in the nanotechnology and nanoscience field have attracted great attention due to diversity of potential applications and significant property improvement when compared to conventional composites. In this work, commercial formulations of polyester-based powder coating with 0, 2 and 4% (w/w) of montmorillonite (MMT) were obtained by incorporation in the melting state and characterized by TEM, SEM, DSC, TGA and XRD. The nanocoatings were applied on the mild carbon steel panels by electrostatic paint. The microscopy analysis showed MMT in the coating film, predominantly in the exfoliated form, corroborated by XRD results. Some tactoid structures and a surface film with some defects and porous were also revealed. Progressive reduction of crosslinking temperature and thermal stability was observed in thermal analysis. The best clay dispersion in the coating and a higher quality film were achieved at 2% MMT concentration. (author)

  6. Infrared characterization of strontium titanate thin films

    International Nuclear Information System (INIS)

    Almeida, B.G.; Pietka, A.; Mendes, J.A.

    2004-01-01

    Strontium titanate thin films have been prepared at different oxygen pressures with various post-deposition annealing treatments. The films were deposited by pulsed laser ablation at room temperature on Si(0 0 1) substrates with a silica buffer layer. Infrared reflectance measurements were performed in order to determine relevant film parameters such as layer thicknesses and chemical composition. The infrared reflectance spectra were fitted by using adequate dielectric function forms for each layer. The fitting procedure provided the extraction of the dielectric functions of the strontium titanate film, the silica layer and the substrate. The as-deposited films are found to be amorphous, and their infrared spectra present peaks corresponding to modes with high damping constants. As the annealing time and temperature increases the strontium titanate layer becomes more ordered so that it can be described by its SrTiO 3 bulk mode parameters. Also, the silica layer grows along with the ordering of the strontium titanate film, due to oxidation during annealing

  7. Low-Latitude Ethane Rain on Titan

    Science.gov (United States)

    Dalba, Paul A.; Buratti, Bonnie J.; Brown, R. H.; Barnes, J. W.; Baines, K. H.; Sotin, C.; Clark, R. N.; Lawrence, K. J.; Nicholson, P. D.

    2012-01-01

    Cassini ISS observed multiple widespread changes in surface brightness in Titan's equatorial regions over the past three years. These brightness variations are attributed to rainfall from cloud systems that appear to form seasonally. Determining the composition of this rainfall is an important step in understanding the "methanological" cycle on Titan. I use data from Cassini VIMS to complete a spectroscopic investigation of multiple rain-wetted areas. I compute "before-and-after" spectral ratios of any areas that show either deposition or evaporation of rain. By comparing these spectral ratios to a model of liquid ethane, I find that the rain is most likely composed of liquid ethane. The spectrum of liquid ethane contains multiple absorption features that fall within the 2-micron and 5-micron spectral windows in Titan's atmosphere. I show that these features are visible in the spectra taken of Titan's surface and that they are characteristically different than those in the spectrum of liquid methane. Furthermore, just as ISS saw the surface brightness reverting to its original state after a period of time, I show that VIMS observations of later flybys show the surface composition in different stages of returning to its initial form.

  8. Reduced-graphene-oxide-and-strontium-titanate-based double ...

    Indian Academy of Sciences (India)

    GO)/strontium titanate were pre- ... R-GO and strontium titanate were synthesized and characterized before ... Microwave absorption capabilities of the composite absorbers were investigated using a .... was backed with a conducting metal sheet.

  9. Plastic Deformation Induced by Nanoindentation Test Applied on ZrN/Si3N4 Multilayer Coatings

    Directory of Open Access Journals (Sweden)

    Zhengtao Wu

    2017-12-01

    Full Text Available ZrN/Si3N4 multilayer coating that alternates with either nanocrystalline ZrN or amorphous Si3N4 interlayers was fabricated by reactively magnetron sputtering in an Ar-N2 mixture atmosphere. The thicknesses of the nanocrystalline ZrN and the amorphous Si3N4 interlayers are ~12.5 and 2.5 nm, respectively. The ZrN/Si3N4 coating exhibits a promoted hardness of 28.6 ± 1.2 GPa when compared to the binary ZrN. Microstructure evolution just underneath the nanoindentation impression of the ZrN/Si3N4 multilayer coating has been investigated. The result indicates that both ZrN nanograin rotations and plastic flow of the Si3N4 interlayers contribute to the permanent deformation of the multilayer coating induced by the nanoindentation. In addition, the introduction of the a-Si3N4 interlayers hinders both the initiation and propagation of microcracks when the multilayer coating was applied to the scratch test. The propagation deflection of the microcracks was observed attributed to the heterogenous interface, which produces the hardness promotion of the multilayer coating eventually.

  10. Cryovolcanism on Titan

    Science.gov (United States)

    Mitri, G.; Showman, A. P.; Lunine, J. I.; Lopes, R. M.

    2008-12-01

    Remote sensing observations yield evidence for cryovolcanism on Titan, and evolutionary models support (but do not require) the presence of an ammonia-water subsurface ocean. The impetus for invoking ammonia as a constituent in an internal ocean and cryovolcanic magma comes from two factors. First, ammonia-water liquid has a lower freezing temperature than pure liquid water, enabling cryovolcanism under the low- temperature conditions prevalent in the outer Solar System. Second, pure water is negatively buoyant with respect to pure water ice, which discourages eruption from the subsurface ocean to the surface. In contrast, the addition of ammonia to the water decreases its density, hence lessening this problem of negative buoyancy. A marginally positive buoyant ammonia-water mixture might allow effusive eruptions from a subsurface ocean. If the subsurface ocean were positively buoyant, all the ammonia would have been erupted very early in Titan's history. Contrary to this scenario, Cassini-Huygens has so far observed neither a global abundance nor a complete dearth of cryovolcanic features. Further, an ancient cryovolcanic epoch cannot explain the relative youth of Titan's surface. Crucial to invoking ammonia-water resurfacing as the source of the apparently recent geological activity is not how to make ammonia-water volcanism work (because the near neutral buoyancy of the ammonia-water mixture encourages an explanation), but rather how to prevent eruption from occurring so easily that cryovolcanic activity is over early on. Although cryovolcanism by ammonia-water has been proposed as a resurfacing process on Titan, few models have specifically dealt with the problem of how to transport ammonia-water liquid onto the surface. We proposed a model of cryovolcanism that involve cracking at the base of the ice shell and formation of ammonia-water pockets in the ice. While the ammonia-water pockets cannot easily become neutral buoyant and promote effusive eruptions

  11. TITAN: an advanced three-dimensional coupled neutronic/thermal-hydraulics code for light water nuclear reactor core analysis

    International Nuclear Information System (INIS)

    Griggs, D.P.; Kazimi, M.S.; Henry, A.F.

    1984-06-01

    The three-dimensional nodal neutronics code QUANDRY and the three-dimensional two-fluid thermal-hydraulics code THERMIT are combined into TITAN. Steady-state and transient coupling methodologies based upon a tandem structure were devised and implemented. Additional models for nuclear feedback, equilibrium xenon and direct moderator heating were added. TITAN was tested using a boiling water two channel problem and the coupling methodologies were shown to be effective. Simulated turbine trip transients and several control rod withdrawal transients were analyzed with good results. Sensitivity studies indicated that the time-step size can affect transient results significantly. TITAN was also applied to a quarter core PWR problem based on a real reactor geometry. The steady-state results were compared to a solution produced by MEKIN-B and poor agreement between the horizontal power shapes was found. Calculations with various mesh spacings showed that the mesh spacings in the MEKIN-B analysis were too large to produce accurate results with a finite difference method. The TITAN results were shown to be reasonable. A pair of control rod ejection accidents were also analyzed with TITAN. A comparison of the TITAN PWR control rod ejection results with results from coupled point kinetics/thermal-hydraulics analyses showed that the point kinetics method used (adiabatic method for control rod reactivities, steady-state flux shape for core-averaged reactivity feedback) underpredicted the power excursion in one case and overpredicted it in the other. It was therefore concluded that point kinetics methods should be used with caution and that three-dimensional codes like TITAN are superior for analyzing PWR control rod ejection transients

  12. Nanoparticle/Polymer Nanocomposite Bond Coat or Coating

    Science.gov (United States)

    Miller, Sandi G.

    2011-01-01

    This innovation addresses the problem of coatings (meant to reduce gas permeation) applied to polymer matrix composites spalling off in service due to incompatibility with the polymer matrix. A bond coat/coating has been created that uses chemically functionalized nanoparticles (either clay or graphene) to create a barrier film that bonds well to the matrix resin, and provides an outstanding barrier to gas permeation. There is interest in applying clay nanoparticles as a coating/bond coat to a polymer matrix composite. Often, nanoclays are chemically functionalized with an organic compound intended to facilitate dispersion of the clay in a matrix. That organic modifier generally degrades at the processing temperature of many high-temperature polymers, rendering the clay useless as a nano-additive to high-temperature polymers. However, this innovation includes the use of organic compounds compatible with hightemperature polymer matrix, and is suitable for nanoclay functionalization, the preparation of that clay into a coating/bondcoat for high-temperature polymers, the use of the clay as a coating for composites that do not have a hightemperature requirement, and a comparable approach to the preparation of graphene coatings/bond coats for polymer matrix composites.

  13. Applying linear programming model to aggregate production planning of coated peanut products

    Science.gov (United States)

    Rohmah, W. G.; Purwaningsih, I.; Santoso, EF S. M.

    2018-03-01

    The aim of this study was to set the overall production level for each grade of coated peanut product to meet market demands with a minimum production cost. The linear programming model was applied in this study. The proposed model was used to minimize the total production cost based on the limited demand of coated peanuts. The demand values applied to the method was previously forecasted using time series method and production capacity aimed to plan the aggregate production for the next 6 month period. The results indicated that the production planning using the proposed model has resulted a better fitted pattern to the customer demands compared to that of the company policy. The production capacity of product family A, B, and C was relatively stable for the first 3 months of the planning periods, then began to fluctuate over the next 3 months. While, the production capacity of product family D and E was fluctuated over the 6-month planning periods, with the values in the range of 10,864 - 32,580 kg and 255 – 5,069 kg, respectively. The total production cost for all products was 27.06% lower than the production cost calculated using the company’s policy-based method.

  14. The greenhouse and antigreenhouse effects on Titan

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, James B.; Courtin, Regis

    1991-01-01

    The parallels between the atmospheric thermal structure of the Saturnian satellite Titan and the hypothesized terrestrial greenhouse effect can serve as bases for the evaluation of competing greenhouse theories. Attention is presently drawn to the similarity between the roles of H2 and CH4 on Titan and CO2 and H2O on earth. Titan also has an antigreenhouse effect due to a high-altitude haze layer which absorbs at solar wavelengths, while remaining transparent in the thermal IR; if this haze layer were removed, the antigreenhouse effect would be greatly reduced, exacerbating the greenhouse effect and raising surface temperature by over 20 K.

  15. Raising the Titanic.

    Science.gov (United States)

    Baker, Romona

    1990-01-01

    Described is an activity in which groups of students investigate engineering principles by writing a feasibility study to raise the luxury liner, Titanic. The problem statement and directions, and suggestions for problem solutions are included. (CW)

  16. Isotherms of ion exchange on titanates of alkaline metals

    International Nuclear Information System (INIS)

    Fillina, L.P.; Belinskaya, F.A.

    1986-01-01

    Present article is devoted to isotherms of ion exchange on titanates of alkaline metals. Therefore, finely dispersed hydrated titanates of alkaline metals (lithium, sodium, potassium) with ion exchange properties are obtained by means of alkaline hydrolysis of titanium chloride at high ph rates. Sorption of cations from salts solution of Li 2 SO 4 , NaNO 3 , Ca(NO 3 ) 2 , AgNO 3 by titanates is studied.

  17. Titan Lifting Entry & Atmospheric Flight (T-LEAF) Science Mission

    Science.gov (United States)

    Lee, G.; Sen, B.; Ross, F.; Sokol, D.

    2016-12-01

    Northrop Grumman has been developing the Titan Lifting Entry & Atmospheric Flight (T-LEAF) sky rover to roam the lower atmosphere and observe at close quarters the lakes and plains of Saturn's ocean moon, Titan. T-LEAF also supports surface exploration and science by providing precision delivery of in-situ instruments to the surface of Titan. T-LEAF is a highly maneuverable sky rover and its aerodynamic shape (i.e., a flying wing) does not restrict it to following prevailing wind patterns on Titan, but allows mission operators to chart its course. This freedom of mobility allows T-LEAF to follow the shorelines of Titan's methane lakes, for example, or to target very specific surface locations. We will present a straw man concept of T-LEAF, including size, mass, power, on-board science payloads and measurement, and surface science dropsonde deployment CONOPS. We will discuss the various science instruments and their vehicle level impacts, such as meteorological and electric field sensors, acoustic sensors for measuring shallow depths, multi-spectral imagers, high definition cameras and surface science dropsondes. The stability of T-LEAF and its long residence time on Titan will provide for time to perform a large aerial survey of select prime surface targets deployment of dropsondes at selected locations surface measurements that are coordinated with on-board remote measurements communication relay capabilities to orbiter (or Earth). In this context, we will specifically focus upon key factors impacting the design and performance of T-LEAF science: science payload accommodation, constraints and opportunities characteristics of flight, payload deployment and measurement CONOPS in the Titan atmosphere. This presentation will show how these factors provide constraints as well as enable opportunities for novel long duration scientific studies of Titan's surface.

  18. Experimental simulations of ethylene evaporites on Titan

    Science.gov (United States)

    Czaplinski, E.; Farnsworth, K.; Singh, S.; Chevrier, V.

    2017-12-01

    Titan has an abundance of lakes and seas, as identified by the Cassini spacecraft. Major components of these liquid bodies include methane (CH4) and ethane (C2H6), however minor constituents are also thought to exist (e.g. ethylene (C2H4)). As the lakes and seas evaporate, 5-μm-bright deposits, resembling evaporite deposits on Earth, are left behind in a "bathtub ring" fashion. Previous studies include models of evaporites, and observations of the 5-μm-bright regions, but the community is still lacking a complete suite of experimental evaporite studies. In this study, we experimentally investigate evaporites in order to determine their composition and how they affect infrared spectra during the evaporation process. The University of Arkansas owns a specialized chamber that simulates the surface conditions of Titan ( 90 K and 1.5 bar). Gaseous hydrocarbons are condensed within the chamber and analyzed with Fourier Transform Infrared (FTIR) Spectroscopy and band depth calculations. In this study, three types of experiments were performed: ethane/ethylene, methane/ethylene, and methane/ethane/ethylene. For these experiments, methane was the only species that readily evaporated at Titan conditions (due to its high volatility), while ethane, being the more stable solvent, did not readily evaporate. Therefore, we will present spectral results of ethylene evaporite formation within these mixtures. Our results imply that evaporite formation is strongly dependent on the composition of the solvent. The north polar lakes of Titan are predicted to be methane-rich, indicating that they may be more likely to form evaporites. Alternatively, Ontario Lacus, a south polar lake, is predominately composed of ethane, which may make it more difficult to form evaporites. As we continue to study Titan's mysterious lakes and seas, we hope to draw insights on their exact composition, conditions for evaporite formation, habitability potential, and comparing Titan to prebiotic Earth.

  19. Titan's Topography and Shape at the End of the Cassini Mission

    Science.gov (United States)

    Corlies, P.; Hayes, A. G.; Birch, S. P. D.; Lorenz, R.; Stiles, B. W.; Kirk, R.; Poggiali, V.; Zebker, H.; Iess, L.

    2017-12-01

    With the conclusion of the Cassini mission, we present an updated topographic map of Titan, including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets available from the mission. We use radial basis functions to interpolate the sparse data set, which covers only ˜9% of Titan's global area. The most notable updates to the topography include higher coverage of the poles of Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We also present a statistical analysis of the error in the derived products and perform a global minimization on a profile-by-profile basis to account for observed biases in the input data set. We find a greater flattening of Titan than measured, additional topographic rises in Titan's southern hemisphere and better constrain the possible locations of past and present liquids on Titan's surface.

  20. Tritium systems for the TITAN reversed-field pinch fusion reactor design

    International Nuclear Information System (INIS)

    Martin, R.C.; Sze, D.K.; Bartlit, J.R.; Gierszewski, P.J.

    1987-01-01

    Tritium systems for the TITAN reversed-field pinch (RFP) fusion reactor study have been designed for two blanket concepts. The TITAN-1 design uses a self-cooled liquid-lithium blanket. The TITAN-2 design uses a self-cooled aqueous-solution blanket, with lithium nitrate dissolved in the water for tritium breeding. Tritium inventory, release, and safety margins are within regulatory limits, at acceptable costs. Major issues for TITAN-1 are plasma-driven permeation, the need for a secondary coolant loop, tritium storage requirements, redundancy in the plasma exhaust system, and minimal isotopic distillation of the exhaust. TITAN-1 fuel cleanup, reprocessing, and air detritiation systems are described in detail

  1. The seasonal cycle of Titan's detached haze

    Science.gov (United States)

    West, Robert A.; Seignovert, Benoît; Rannou, Pascal; Dumont, Philip; Turtle, Elizabeth P.; Perry, Jason; Roy, Mou; Ovanessian, Aida

    2018-04-01

    Titan's `detached' haze, seen in Voyager images in 1980 and 1981 and monitored by the Cassini Imaging Science Subsystem (ISS) during the period 2004-2017, provides a measure of seasonal activity in Titan's mesosphere with observations over almost half of Saturn's seasonal cycle. Here we report on retrieved haze extinction profiles that reveal a depleted layer (having a diminished aerosol content), visually manifested as a gap between the main haze and a thin, detached upper layer. Our measurements show the disappearance of the feature in 2012 and its reappearance in 2016, as well as details after the reappearance. These observations highlight the dynamical nature of the detached haze. The reappearance seems congruent with earlier descriptions by climate models but more complex than previously described. It occurs in two steps, first as haze reappearing at 450 ± 20 km and one year later at 510 ± 20 km. These observations provide additional tight and valuable constraints about the underlying mechanisms, especially for Titan's mesosphere, that control Titan's haze cycle.

  2. Novel Bioactive Titanate Layers Formed on Ti Metal and Its Alloys by Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Tadashi Kokubo

    2009-12-01

    Full Text Available Sodium titanate formed on Ti metal by NaOH and heat treatments induces apatite formation on its surface in a body environment and bonds to living bone. These treatments have been applied to porous Ti metal in artificial hip joints, and have been used clinically in Japan since 2007. Calcium titanate formed on Ti-15Zr-4Nb-4Ta alloy by NaOH, CaCl2, heat, and water treatments induces apatite formation on its surface in a body environment. Titanium oxide formed on porous Ti metal by NaOH, HCl, and heat treatments exhibits osteoinductivity as well as osteoconductivity. This is now under clinical tests for application to a spinal fusion device.

  3. The tide in the seas of Titan

    International Nuclear Information System (INIS)

    Sagan, C.; Dermott, S.F.

    1982-01-01

    It is argued that, if Titan has oceans consisting of liquid methane, then the present high eccentricity of the satellite necessitates that the depth would be greater than 400 m. Such an ocean should be detectable by radar. The effects of tidal dissipation due to the possible existence of an ocean on Titan are considered. (author)

  4. Landscape Evolution of Titan

    Science.gov (United States)

    Moore, Jeffrey

    2012-01-01

    Titan may have acquired its massive atmosphere relatively recently in solar system history. The warming sun may have been key to generating Titan's atmosphere over time, starting from a thin atmosphere with condensed surface volatiles like Triton, with increased luminosity releasing methane, and then large amounts of nitrogen (perhaps suddenly), into the atmosphere. This thick atmosphere, initially with much more methane than at present, resulted in global fluvial erosion that has over time retreated towards the poles with the removal of methane from the atmosphere. Basement rock, as manifested by bright, rough, ridges, scarps, crenulated blocks, or aligned massifs, mostly appears within 30 degrees of the equator. This landscape was intensely eroded by fluvial processes as evidenced by numerous valley systems, fan-like depositional features and regularly-spaced ridges (crenulated terrain). Much of this bedrock landscape, however, is mantled by dunes, suggesting that fluvial erosion no longer dominates in equatorial regions. High midlatitude regions on Titan exhibit dissected sedimentary plains at a number of localities, suggesting deposition (perhaps by sediment eroded from equatorial regions) followed by erosion. The polar regions are mainly dominated by deposits of fluvial and lacustrine sediment. Fluvial processes are active in polar areas as evidenced by alkane lakes and occasional cloud cover.

  5. Reduced-graphene-oxide-and-strontium-titanate-based double

    Indian Academy of Sciences (India)

    Microwave-absorbing materials based on reduced graphene oxide (r-GO)/ strontium titanate were prepared by embedding in epoxy matrix. R-GO and strontium titanate were synthesized and characterized before composite fabrication. Microstructures of the constituent elements were studied by scanning electron ...

  6. Cation interdiffusion in polycrystalline calcium and strontium titanate

    International Nuclear Information System (INIS)

    Butler, E.P.; Jain, H.; Smyth, D.M.

    1991-01-01

    This paper discusses a method that has been developed to study bulk lattice interdiffusion between calcium and strontium titanate by fabrication of a diffusion couple using cosintering. The measured interdiffusion coefficients, D(C), indicate that strontium impurity diffusion in calcium titanate occurs at a faster rate than calcium impurity diffusion in strontium titanate. These interdiffusion coefficients are composition independent when the concentration of the calcium cation exceeds that of the strontium cation; otherwise D(C) is strongly composition dependent. Investigations into the effect of cation nonstoichiometry give results that are consistent with a defect incorporation reaction in which excess TiO 2 , within the solid solubility limit, produces A-site cation vacancies as compensating defects. The interdiffusion coefficients increase with increasing concentrations of TiO 2 , so it is concluded that interdiffusion of these alkaline-earth cations in their titanates occurs via a vacancy mechanism

  7. Mission Techniques for Exploring Saturn's icy moons Titan and Enceladus

    Science.gov (United States)

    Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

    2010-05-01

    The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiѐre hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit within NASA's New Frontiers or ESA's Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, several mission concepts have been developed that potentially fit within various cost classes. Also, a clear blueprint has been laid out for early efforts critical toward reducing the risks inherent in such missions. The purpose of this paper is to provide a brief overview of potential Titan (and Enceladus) mission

  8. Detailed exploration of Titan with a Montgolfiere aerobot

    Science.gov (United States)

    Spilker, T.; Tipex Team

    The International Cassini/Huygens (CH) mission has verified the expectation that Saturn's moon Titan offers many opportunities for studying high-priority planetary and astrobiology science objectives. CH results to date show that this world, though entirely alien in its frigid environment, presents an Earth-like and diverse appearance due to the relative balance of competing forces such as geology/tectonics, meteorology, aeronomy, and cosmic impacts. But with the limitations of a single Huygens probe, and a finite number of Cassini flybys limited in proximity and remote sensing resolution by Titan's thick atmosphere and hazes, there is much science to be done there after the CH mission has ended. Detailed exploration of Titan's surface and lower atmosphere, especially for astrobiological objectives, is best addressed by in situ investigations. The atmosphere and its hazes severely restrict orbital remote sensing: Titan cannot be mapped from orbit in the same manner as Mars, at (essentially) arbitrarily high resolution, and limited infrared (IR) windows allow only gross compositional interpretations. After CH indeed there will be further orbital investigations to be carried out, notably completion of the global mapping by Synthetic Aperture Radar and IR mapping spectrometry begun by CH, at the best resolutions practical from orbit. But to fully understand Titan as an evolving, planetary-scale body and an abode of preserved protobiological chemistry will require a platform that has access to, and mobility at, the surface and the lowest few kilometers of the atmosphere. The TiPEx study team weighed the options for Titan in situ exploration, and finds that a mission based on a Montgolfiere (a type of hot-air balloon) aerobot is the best candidate for post-CH exploration. Ground-based platforms of the type used to date on Mars are far too limited in range to sample the diversity of Titan, and do not adequately investigate the lower atmosphere. Titan's cold, dense

  9. Surface-Atmosphere Connections on Titan: A New Window into Terrestrial Hydroclimate

    Science.gov (United States)

    Faulk, Sean

    This dissertation investigates the coupling between the large-scale atmospheric circulation and surface processes on Titan, with a particular focus on methane precipitation and its influence on surface geomorphology and hydrology. As the only body in the Solar System with an active hydrologic cycle other than Earth, Titan presents a valuable laboratory for studying principles of hydroclimate on terrestrial planets. Idealized general circulation models (GCMs) are used here to test hypotheses regarding Titan's surface-atmosphere connections. First, an Earth-like GCM simulated over a range of rotation rates is used to evaluate the effect of rotation rate on seasonal monsoon behavior. Slower rotation rates result in poleward migration of summer rain, indicating a large-scale atmospheric control on Titan's observed dichotomy of dry low latitudes and moist high latitudes. Second, a Titan GCM benchmarked against observations is used to analyze the magnitudes and frequencies of extreme methane rainstorms as simulated by the model. Regional patterns in these extreme events correlate well with observed geomorphic features, with the most extreme rainstorms occurring in mid-latitude regions associated with high alluvial fan concentrations. Finally, a planetary surface hydrology scheme is developed and incorporated into a Titan GCM to evaluate the roles of surface flow, subsurface flow, infiltration, and groundmethane evaporation in Titan's climate. The model reproduces Titan's observed surface liquid and cloud distributions, and reaches an equilibrium state with limited interhemispheric transport where atmospheric transport is approximately balanced by subsurface transport. The equilibrium state suggests that Titan's current hemispheric surface liquid asymmetry, favoring methane accumulation in the north, is stable in the modern climate.

  10. Titan 2D: Understanding Titan’s Seasonal Atmospheric Cycles

    Science.gov (United States)

    Wong, Michael; Zhang, X.; Li, C.; Hu, R.; Shia, R.; Newman, C.; Müller-Wodarg, I.; Yung, Y.

    2013-10-01

    In this study, we present results from a novel two-dimensional (2D) model that simulates the physics and chemistry of Titan’s atmosphere. Despite being an icy moon of Saturn, Titan is the only Solar System object aside from Earth that is sheathed by a thick nitrogen-dominated atmosphere. This vulnerable gaseous envelope—an embodiment of a delicate coupling between photochemistry, radiation, and dynamics—is Nature’s laboratory for the synthesis of complex organic molecules. Titan’s large obliquity generates pronounced seasonal cycles in its atmosphere, and the Cassini spacecraft has been observing these variations since 2004. In particular, Cassini measurements show that the latitudinal distribution of Titan’s rich mélange of hydrocarbon species follows seasonal patterns. The mixing ratios of hydrocarbons increase with latitude towards the winter pole, suggesting a pole-to-pole circulation that reverses after equinox. Using a one-dimensional photochemical model of Titan’s atmosphere, we show that photochemistry alone cannot produce the observed meridional hydrocarbon distribution. This necessitates the employment of a 2D chemistry-transport model that includes meridional circulation as well as diffusive processes and photochemistry. Of additional concern, no previous 2D model of Titan extends beyond 500 km altitude—a critical limitation since the peak of methane photolysis is at 800 km. Our 2D model is the first to include Titan’s stratosphere, mesosphere, and thermosphere. The meridional circulation in our 2D model is derived from the outputs of two general circulation models (GCMs): the TitanWRF GCM (Newman et al. 2011) covering the troposphere, stratosphere, and lower mesosphere, and a thermosphere general circulation model (TGCM) covering the remainder of the atmosphere through the thermosphere (Müller-Wodarg et al. 2003; 2008). This presentation will focus on the utilization of these advances applied to the 2D Caltech/JPL KINETICS model to

  11. RESEARCH OF PROCESS OF AN ALLOYING OF THE FUSED COATINGS RECEIVED FROM THE SUPERFICIAL ALLOYED WIRE BY BORON WITH IN ADDITIONALLY APPLIED ELECTROPLATED COATING OF CHROME AND COPPER

    Directory of Open Access Journals (Sweden)

    V. A. Stefanovich

    2015-01-01

    Full Text Available Researches on distribution of chrome and copper in the fused coating received from the superficial alloyed wire by boron with in additionally applied electroplated coating of chrome and copper were executed. The structure of the fused coating consists of dendrites on which borders the boride eutectic is located. It is established that the content of chrome in dendrites is 1,5– 1,6 times less than in the borid; distribution of copper on structure is uniformed. Coefficients of digestion of chrome and copper at an argon-arc welding from a wire electrode with electroplated coating are established. The assimilation coefficient for chrome is equal to 0,9–1,0; for copper – 0,6–0,75.

  12. Progressive Climate Change on Titan: Implications for Habitability

    Science.gov (United States)

    Moore, J. M.; A. D. Howard

    2014-01-01

    Titan's landscape is profoundly shaped by its atmosphere and comparable in magnitude perhaps with only the Earth and Mars amongst the worlds of the Solar System. Like the Earth, climate dictates the intensity and relative roles of fluvial and aeolian activity from place to place and over geologic time. Thus Titan's landscape is the record of climate change. We have investigated three broad classes of Titan climate evolution hypotheses (Steady State, Progressive, and Cyclic), regulated by the role, sources, and availability of methane. We favor the Progressive hypotheses, which we will outline here, then discuss their implication for habitability.

  13. Decontamination of 2-chloroethyl ethylsulfide using titanate nanoscrolls

    Science.gov (United States)

    Kleinhammes, Alfred; Wagner, George W.; Kulkarni, Harsha; Jia, Yuanyuan; Zhang, Qi; Qin, Lu-Chang; Wu, Yue

    2005-08-01

    Titanate nanoscrolls, a recently discovered variant of TiO 2 nanocrystals, are tested as reactive sorbent for chemical warfare agent (CWA) decontamination. The large surface area of the uncapped tubules provides the desired rapid absorption of the contaminant while water molecules, intrinsic constituents of titanate nanoscrolls, provide the necessary chemistry for hydrolytic reaction. In this study the decomposition of 2-chloroethyl ethylsulfide (CEES), a simulant for the CWA mustard, was monitored using 13C NMR. The NMR spectra reveal reaction products as expected from the hydrolysis of CEES. This demonstrates that titanate nanoscrolls could potentially be employed as a decontaminant for CWAs.

  14. Diffusion complex layers of TiC-Ni-Mo type produced on steel during vacuum titanizing process combined with the electrolytic deposition

    International Nuclear Information System (INIS)

    Kasprzycka, E.; Krolikowski, A.

    1999-01-01

    Diffusion carbide layers produced on steel surface by means of vacuum titanizing process have been studied. A new technological process combining a vacuum titanizing with an electrolytic deposition of Ni-Mo alloy has been proposed to increase of corrosion resistance of carbide layers. The effect of preliminary electrolytic deposition of Ni-Mo alloy on the NC10 steel surface on the titanized layer structure and its corrosion resistance has ben investigated. As a result, diffusion complex layers of TiC-Ni-Mo type on NC10 steel surface have been obtained. An X-ray structural analysis of titanized surfaces on NC10 steel precovered with an electrolytic Ni-Mo alloy coating (70%Ni+30%Mo) revealed a presence of titanium carbide TiC, NiTi, MoTi and trace quantity of austenite. The image of the TiC-Ni-Mo complex layer on NC10 steel surface obtained by means of joined SEM+TEM method and diagrams of elements distribution in the layer diffusion zone have been shown. Concentration of depth profiles of Ti, Ni, Mo, Cr and Fe in the layer diffusion zone obtained by means of the joined EDS+TEM method are shown. Concentration depth profiles of Ti, Ni, Mo, Cr and Fe in the layer diffusion zone obtained by means of the X r ay microanalysis and microhardness of the layer are shown. An X-ray structural analysis of titanized surfaces on the NC10 steel, without Ni-Mo alloy layer, revealed only a substantial presence of titanium carbide TiC. For corrosion resistance tests the steel samples with various diffusion layers and without layers were used: (i) the TiC-Ni-Mo titanized complex layers on NC10 steel, (ii) the TiC titanized carbide layers on the NC10 steel, (iii) the NC10 steel without layers. Corrosion measurements of sample under test have been performed in 0.1 M H 2 SO 4 by means of potentiodynamic polarization and electrochemical impedance tests. It has been found that the corrosion resistance of titanized steel samples with the TiC and TiC-Ni-Mo layers is higher than for the steel

  15. Crater Topography on Titan: Implications for Landscape Evolution

    Science.gov (United States)

    Neish, Catherine D.; Kirk, R.L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.

    2013-01-01

    We present a comprehensive review of available crater topography measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 +/- 0.0003 (for the largest crater studied, Menrva, D approximately 425 km) and 0.017 +/- 0.004 (for the smallest crater studied, Ksa, D approximately 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.

  16. Synthesis and structural characterization of Ce-doped bismuth titanate

    International Nuclear Information System (INIS)

    Pavlovic, Nikolina; Srdic, Vladimir V.

    2009-01-01

    Ce-modified bismuth titanate nanopowders Bi 4-x Ce x Ti 3 O 12 (x ≤ 1) have been synthesized using a coprecipitation method. DTA/TG, FTIR, XRD, SEM/EDS and BET methods were used in order to investigate the effect of Ce-substitution on the structure, morphology and sinterability of the obtained powders. The phase structure investigation revealed that after calcinations at 600 deg. C powder without Ce addition exhibited pure bismuth titanate phase; however, powders with Ce (x = 0.25, 0.5 and 0.75) had bismuth titanate pyrochlore phase as the second phase. The strongest effect of Ce addition on the structure was noted for the powder with the highest amount of Ce (x = 1) having a cubic pyrochlore structure. The presence of pure pyrochlore phase was explained by its stabilization due to the incorporation of cerium ions in titanate structure. Ce-modified bismuth titanate ceramic had a density over 95% of theoretical density and the fracture in transgranular manner most probably due to preferable distribution of Ce in boundary region

  17. Heavy Ion Formation in Titan's Ionosphere: Magnetospheric Introduction of Free Oxygen and a Source of Titan's Aerosols?

    Science.gov (United States)

    Sittler, E. C., Jr.; Ali, A.; Cooper, J. F.; Hartle, R. E.; Johnson, R. E.; Coates, A. J.; Young, D. T.

    2009-01-01

    Discovery by Cassini's plasma instrument of heavy positive and negative ions within Titan's upper atmosphere and ionosphere has advanced our understanding of ion neutral chemistry within Titan's upper atmosphere, primarily composed of molecular nitrogen, with approx.2.5% methane. The external energy flux transforms Titan's upper atmosphere and ionosphere into a medium rich in complex hydrocarbons, nitriles and haze particles extending from the surface to 1200 km altitudes. The energy sources are solar UV, solar X-rays, Saturn's magnetospheric ions and electrons, solar wind and shocked magnetosheath ions and electrons, galactic cosmic rays (CCR) and the ablation of incident meteoritic dust from Enceladus' E-ring and interplanetary medium. Here it is proposed that the heavy atmospheric ions detected in situ by Cassini for heights >950 km, are the likely seed particles for aerosols detected by the Huygens probe for altitudes <100km. These seed particles may be in the form of polycyclic aromatic hydrocarbons (PAH) containing both carbon and hydrogen atoms CnHx. There could also be hollow shells of carbon atoms, such as C60, called fullerenes which contain no hydrogen. The fullerenes may compose a significant fraction of the seed particles with PAHs contributing the rest. As shown by Cassini, the upper atmosphere is bombarded by magnetospheric plasma composed of protons, H(2+) and water group ions. The latter provide keV oxygen, hydroxyl and water ions to Titan's upper atmosphere and can become trapped within the fullerene molecules and ions. Pickup keV N(2+), N(+) and CH(4+) can also be implanted inside of fullerenes. Attachment of oxygen ions to PAH molecules is uncertain, but following thermalization O(+) can interact with abundant CH4 contributing to the CO and CO2 observed in Titan's atmosphere. If an exogenic keV O(+) ion is implanted into the haze particles, it could become free oxygen within those aerosols that eventually fall onto Titan's surface. The process

  18. Titan's Stratospheric Condensibles at High Northern Latitudes During Northern Winter

    Science.gov (United States)

    Anderson, Carrie; Samuelson, R.; Achterberg, R.

    2012-01-01

    The Infrared Interferometer Spectrometer (IRIS) instrument on board Voyager 1 caught the first glimpse of an unidentified particulate feature in Titan's stratosphere that spectrally peaks at 221 per centimeter. Until recently, this feature that we have termed 'the haystack,' has been seen persistently at high northern latitudes with the Composite Infrared Spectrometer (CIRS) instrument onboard Cassini, The strength of the haystack emission feature diminishes rapidly with season, becoming drastically reduced at high northern latitudes, as Titan transitions from northern winter into spring, In contrast to IRIS whose shortest wavenumber was 200 per centimeter, CIRS extends down to 10 per centimeter, thus revealing an entirely unexplored spectral region in which nitrile ices have numerous broad lattice vibration features, Unlike the haystack, which is only found at high northern latitudes during northern winter/early northern spring, this geometrically thin nitrile cloud pervades Titan's lower stratosphere, spectrally peaking at 160 per centimeter, and is almost global in extent spanning latitudes 85 N to 600 S, The inference of nitrile ices are consistent with the highly restricted altitude ranges over which these features are observed, and appear to be dominated by a mixture of HCN and HC3N, The narrow range in altitude over which the nitrile ices extend is unlike the haystack, whose vertical distribution is significantly broader, spanning roughly 70 kilometers in altitude in Titan's lower stratosphere, The nitrile clouds that CIRS observes are located in a dynamically stable region of Titan's atmosphere, whereas CH4 clouds, which ordinarily form in the troposphere, form in a more dynamically unstable region, where convective cloud systems tend to occur. In the unusual situation where Titan's tropopause cools significantly from the HASI 70.5K temperature minimum, CH4 should condense in Titan's lower stratosphere, just like the aforementioned nitrile clouds, although

  19. Thermogravimetric study of the kinetics of lithium titanate reduction by hydrogen

    International Nuclear Information System (INIS)

    Sonak, Sagar; Rakesh, R.; Jain, Uttam; Mukherjee, Abhishek; Kumar, Sanjay; Krishnamurthy, Nagaiyar

    2014-01-01

    Highlights: • Li 2 TiO 3 powder is synthesized by the gel combustion route. • Activation energy of reduction of Li 2 TiO 3 by H 2 found out to be 27.45 kJ/mol H 2 . • Non-stoichiometric phase of Li 2 TiO 3 is formed in hydrogen atmosphere. • One-dimensional diffusion appears to be the most probable mechanism of reduction. - Abstract: The lithium titanate powder was synthesized by gel-combustion route. The mechanism and the kinetics of hydrogen interaction with lithium titanate powder were studied using non-isothermal thermogravimetric technique. Lithium titanate underwent reduction in hydrogen atmosphere which led to the formation of oxygen deficient non-stoichiometric compound in lithium titanate. One-dimensional diffusion appeared to be the most probable reaction mechanism. The activation energy for reduction of lithium titanate under hydrogen atmosphere was found to be 27.4 kJ/mol/K. Structural changes after hydrogen reduction in lithium titanate were observed in X-ray diffraction analysis

  20. Screening of spontaneous polarization in lead titanate crystals

    International Nuclear Information System (INIS)

    Gavrilyachenko, V.G.; Semenchev, A.F.; Fesenko, E.G.

    1996-01-01

    Results of experimental investigations into electric conductivity of lead titanate crystals with different domain structure including single-domain are reported. The data obtained give grounds to believe that spontaneous titanate polarization is realized by the surface level and charge volumetric of free carriers and ionized impurity

  1. Fabrication and properties of yttrium doped barium titanate film by RF sputtering

    International Nuclear Information System (INIS)

    Igarashi, H.; Yuasa, M.; Okazaki, K.

    1985-01-01

    Semiconductive barium titanate films were fabricated by RF sputtering on fused quartz, alumina and barium titanate ceramic substrates using barium titanate ceramic with a small amount of yttria as a target. The films on the barium titanate substrates turned blue color and showed a small PTC effect by heat-treating at 1000 0 C in the air after deposition at the substrate temperature of 600 0 C

  2. Titanic exploration with GIS

    Science.gov (United States)

    Kerski, J.J.

    2004-01-01

    To help teachers and students investigate one of the world's most famous historical events using the geographic perspective and GIS tools and methods, the U.S. Geological Survey (USGS) created a set of educational lessons based on the RMS Titanic's April 1912 sailing. With these lessons, student researchers can learn about latitude and longitude, map projections, ocean currents, databases, maps, and images through the analysis of the route, warnings, sinking, rescue, and eventual discovery of the submerged ocean liner in 1985. They can also consider the human and physical aspects of the maiden voyage in the North Atlantic Ocean at a variety of scales, from global to regional to local. Likewise, their investigations can reveal how the sinking of the Titanic affected future shipping routes.

  3. Exfoliation and thermal transformations of Nb-substituted layered titanates

    DEFF Research Database (Denmark)

    Song, H.; Sjåstad, Anja O.; Fjellvåg, Helmer

    2011-01-01

    Single-layer Nb-substituted titanate nanosheets of ca. 1 nm thickness were obtained by exfoliating tetrabutylammonium (TBA)-intercalated Nb-substituted titanates in water. AFM images and turbidity measurements reveal that the exfoliated nanosheets crack and corrugate when sonicated. Upon heating...... factors for increasing the transformation temperatures for conversion of the nanosheets to anatase and finally into rutile. It is further tempting to link the delay in crystallization to morphology limitations originating from the nanosheets. The present work shows that layered Nb-titanates...

  4. TandEM: Titan and Enceladus mission

    Science.gov (United States)

    Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, Christophe; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, Ji; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, Catherine D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa,

    2009-01-01

    TandEM was proposed as an L-class (large) mission in response to ESA’s Cosmic Vision 2015–2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini–Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini–Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfière) and possibly several landing probes to be delivered through the atmosphere.

  5. Organic matter in the Titan lakes, and comparison with primitive Earth

    Science.gov (United States)

    Khare, Bishun N.; McKay, C.; Wilhite, P.; Beeler, D.; Carter, M.; Schurmeier, L.; Jagota, S.; Kawai, J.; Nna-Mvondo, D.; Cruikshank, D.; Embaye, T.

    2013-06-01

    Titan is the only world in the solar system besides the Earth that has liquid on its surface. The liquid in the lakes is thought to be composed primarily of ethane with methane and nitrogen in solution. The clouds are thought to be composed of liquid methane drops. Surface liquid is present in polar lakes and in surface materials at equatorial sites. Studying the chemical processing that potentially results from organic material interacting with this liquid is one of the main goals of proposed missions to Titan. We have been engaged in producing tholin under Titan-like conditions for more than three decades, first at the Laboratory for Planetary Studies at Cornell University in collaboration with Late Dr. Carl Sagan and for over a decade at Laboratory for Planetary Studies at NASA Ames Research Center and Carl Sagan Center for the Study of Life in the Universe, SETI Institute. Our focus is to understand the capabilities for analysis of tholin solubility in liquid methane and ethane for flight instruments. Our results are expected to contribute to an understanding of the organic chemistry on Titan and to the development of an explicit and targeted scientific strategy for near term analysis of the products of organic-liquid interactions on Titan. Organics are produced as a haze in Titan's high atmosphere due to photolysis of methane with the Sun's extreme ultraviolet light and subsequent reaction with N. Also tholins are formed at a much higher level on Titan by charged particles of Saturn magnetosphere. However, the presence of organics is not the sole feature, which makes Titan significant to astrobiology; organics are widely present in the outer solar system. The reason Titan is a prime target for future outer solar system missions is the combination of organic material and liquid on the surface; liquid that could over a medium for further organic synthesis. NASA recently selected for further study a Discovery proposal TiME to investigate the chemistry of the

  6. Adhesion strength of lead zirconate titanate sol-gel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Berfield, Thomas A., E-mail: tom.berfield@louisville.edu [Department of Mechanical Engineering, University of Louisville, Louisville, KY 40292 (United States); Kitey, Rajesh [Department of Aerospace Engineering, Indian Institute of Technology Kanpur, Kanpur (India); Kandula, Soma S. [Intel Corporation, Portland, OR (United States)

    2016-01-01

    The adhesion strength between a thin film and substrate is often the critical parameter that controls the initiation as well as the mode of film failure. In this work, a laser-based spallation method is used to determine the adhesion strength of “as deposited” lead zirconate titanate (PZT) sol-gel thin films on the two functionally different substrates. For the first case, PZT sol-gel film is deposited onto bare Si/SiO{sub 2} substrates via spin casting. The extremely high adhesion strength between the film and the substrate necessitated an additional platinum mass superlayer to be deposited on top of the PZT film in order to induce interfacial failure. For the superlayer film system, a hybrid experimental/numerical method is employed for determining the substrate/film interfacial strength, quantified to be in the range of 460–480 MPa. A second substrate variation with lower adhesion strength is also prepared by applying a self-assembled octadecyltrichlorosilane (ODS) monolayer to the Si/SiO{sub 2} substrate prior to the film deposition. For the monolayer-coated substrate case, the adhesion strength is observed to be significantly lower (54.7 MPa) when compared to the earlier case. - Highlights: • A non-contact laser spallation method is used to determine PZT film adhesion. • A mediated self-assembled monolayer is shown to greatly reduce interface strength. • Adhesion strength for even well-bonded thin films was found using a superlayer.

  7. Simulating the 3-D Structure of Titan's Upper Atmosphere

    Science.gov (United States)

    Bell, J. M.; Waite, H.; Westlake, J.; Magee, B.

    2009-05-01

    We present results from the 3-D Titan Global Ionosphere-Thermosphere Model (Bell et al [2009], PSS, in review). We show comparisons between simulated N2, CH4, and H2 density fields and the in-situ data from the Cassini Ion Neutral Mass Spectrometer (INMS). We describe the temperature and wind fields consistent with these density calculations. Variations with local time, longitude, and latitude will be addressed. Potential plasma heating sources can be estimated using the 1-D model of De La Haye et al [2007, 2008] and the impacts on the thermosphere of Titan can be assessed in a global sense in Titan-GITM. Lastly, we will place these findings within the context of recent work in modeling the 2-D structure of Titan's upper atmosphere (Mueller-Wodarg et al [2008]).

  8. METHANE GAS STABILIZES SUPERCOOLED ETHANE DROPLETS IN TITAN'S CLOUDS

    International Nuclear Information System (INIS)

    Wang, Chia C.; Lang, E. Kathrin; Signorell, Ruth

    2010-01-01

    Strong evidence for ethane clouds in various regions of Titan's atmosphere has recently been found. Ethane is usually assumed to exist as ice particles in these clouds, although the possible role of liquid and supercooled liquid ethane droplets has been recognized. Here, we report on infrared spectroscopic measurements of ethane aerosols performed in the laboratory under conditions mimicking Titan's lower atmosphere. The results clearly show that liquid ethane droplets are significantly stabilized by methane gas which is ubiquitous in Titan's nitrogen atmosphere-a phenomenon that does not have a counterpart for water droplets in Earth's atmosphere. Our data imply that supercooled ethane droplets are much more abundant in Titan's clouds than previously anticipated. Possibly, these liquid droplets are even more important for cloud processes and the formation of lakes than ethane ice particles.

  9. Coatings of nanoparticles applied to brachytherapy treatments

    International Nuclear Information System (INIS)

    Gonzalez, Andreza A.D.C.C.; Rostelato, Maria Elisa C.M.; Souza, Carla D.; Rodrigues, Bruna T.; Souza, Daiane C.B.; Zeituni, Carlos A.; Nogueira, Beatriz R.

    2017-01-01

    Brachytherapy is a treatment for cancer in which the radiation is placed close or in contact with the region to be treated saving the surrounding healthy tissues. Nanotechnology is the science that studies the properties of nanometric materials. Nanobrachytherapy in a new field that unites the advantages of brachytherapy with the small size in the nanoparticle, resulting in an even less invasive treatment. In view of the synthesis of the nanoparticles and their use, there is a fundamental role that is made by the coatings, which not only have the function of avoiding the aggregation of particles, but also stabilize and control their functional properties. Among the range of coatings, the most outstanding are polyethylene glycol (PEG) and gum arabica (GA). PEG improves the surface properties of nanoparticles and presents high stability under biomedical conditions. After the synthesis of gold nanoparticles was developed, PEG and gum arabica were successfully incorporated into the surface. In a vial of pyrex, 1 ml of coating agent and 1 ml of nanoparticles was left under gentle shaking for 2 hours. Incorporation was confirmed by DLS and HRTEM. GA requires further study. (author)

  10. Coatings of nanoparticles applied to brachytherapy treatments

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Andreza A.D.C.C.; Rostelato, Maria Elisa C.M.; Souza, Carla D.; Rodrigues, Bruna T.; Souza, Daiane C.B.; Zeituni, Carlos A.; Nogueira, Beatriz R., E-mail: ccg.andreza@gmail.com, E-mail: elisaros@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    Brachytherapy is a treatment for cancer in which the radiation is placed close or in contact with the region to be treated saving the surrounding healthy tissues. Nanotechnology is the science that studies the properties of nanometric materials. Nanobrachytherapy in a new field that unites the advantages of brachytherapy with the small size in the nanoparticle, resulting in an even less invasive treatment. In view of the synthesis of the nanoparticles and their use, there is a fundamental role that is made by the coatings, which not only have the function of avoiding the aggregation of particles, but also stabilize and control their functional properties. Among the range of coatings, the most outstanding are polyethylene glycol (PEG) and gum arabica (GA). PEG improves the surface properties of nanoparticles and presents high stability under biomedical conditions. After the synthesis of gold nanoparticles was developed, PEG and gum arabica were successfully incorporated into the surface. In a vial of pyrex, 1 ml of coating agent and 1 ml of nanoparticles was left under gentle shaking for 2 hours. Incorporation was confirmed by DLS and HRTEM. GA requires further study. (author)

  11. Crater relaxation on Titan aided by low thermal conductivity sand infill

    Science.gov (United States)

    Schurmeier, Lauren R.; Dombard, Andrew J.

    2018-05-01

    Titan's few impact craters are currently many hundreds of meters shallower than the depths expected. Assuming these craters initially had depths equal to that of similar-size fresh craters on Ganymede and Callisto (moons of similar size, composition, and target lithology), then some process has shallowed them over time. Since nearly all of Titan's recognized craters are located within the arid equatorial sand seas of organic-rich dunes, where rain is infrequent, and atmospheric sedimentation is expected to be low, it has been suggested that aeolian infill plays a major role in shallowing the craters. Topographic relaxation at Titan's current heat flow was previously assumed to be an unimportant process on Titan due to its low surface temperature (94 K). However, our estimate of the thermal conductivity of Titan's organic-rich sand is remarkably low (0.025 W m-1 K-1), and when in thick deposits, will result in a thermal blanketing effect that can aid relaxation. Here, we simulate the relaxation of Titan's craters Afekan, Soi, and Sinlap including thermal effects of various amounts of sand inside and around Titan's craters. We find that the combination of aeolian infill and subsequent relaxation can produce the current crater depths in a geologically reasonable period of time using Titan's current heat flow. Instead of needing to fill completely the missing volume with 100% sand, only ∼62%, ∼71%, and ∼97%, of the volume need be sand at the current basal heat flux for Afekan, Soi, and Sinlap, respectively. We conclude that both processes are likely at work shallowing these craters, and this finding contributes to why Titan overall lacks impact craters in the arid equatorial regions.

  12. Freeze cast porous barium titanate for enhanced piezoelectric energy harvesting

    Science.gov (United States)

    Roscow, J. I.; Zhang, Y.; Kraśny, M. J.; Lewis, R. W. C.; Taylor, J.; Bowen, C. R.

    2018-06-01

    Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of barium titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous barium titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast barium titanate with 45 vol.% porosity had a d 33  =  134.5 pC N‑1 compared to d 33  =  144.5 pC N‑1 for dense barium titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of barium titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N‑1 for barium titanate with 45 vol.% porosity, compared to only 1.40 pm2 N‑1 for dense barium titanate. Dense and porous barium titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous barium titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that

  13. Low temperature alkaline pH hydrolysis of oxygen-free Titan tholins

    Science.gov (United States)

    Brassé, Coralie; Buch, Arnaud; Raulin, François; Coll, Patrice; Poch, Olivier; Ramirez, Sandra

    2014-05-01

    been trapped in the likely internal ocean. Then by taking into account the plausible acid-alkaline properties of the water-ammonia ocean, we determine a new probable composition of the cryomagma which could potentially interact with deposited Titan's aerosols. They were also included in our hydrolysis experiments. Taking into account these new data, four different hydrolyses have been applied to oxygen-free tholins. For each type of hydrolysis, we also follow the influence of the hydrolysis temperature on the organic molecules production. References: [1] Mitri et al., 2008. Resurfacing of Titan by ammonia-water cryomagma. Icarus. 196, 216-224. [2] Poch et al., 2011. Production yields of organics of astrobiological interest from H2O-NH3 hydrolysis of Titan's tholins. Planetary and Space Science. 61, 114-123. [3] Tobie et al. 2012. Titan's Bulk Composition Constrained by Cassini-Huygens: implication for internal outgassing. The Astrophysical Journal. 752, 125. [4] Neish et al., 2009. Low temperature hydrolysis of laboratory tholins in ammonia-water solutions: Implications for prebiotic chemistry on Titan. Icarus. 201, 412-421. [5] Hersant et al., 2004. Enrichment in volatiles in the giant planets of the Solar System. Planetary and Space Science. 52, 623-641. [6] Hersant et al., 2008. Interpretation of the carbon abundance in Saturn measured by Cassini. Planetary and Space Science. 56, 1103-1111. Acknowledgements: We acknowledge support from the French Space Agency (CNES) and the European Space Agency (ESA).

  14. Thermal conductivity reduction in oxygen-deficient strontium titanates

    NARCIS (Netherlands)

    Yu, Choongho; Scullin, Matthew L.; Huijben, Mark; Ramesh, Ramamoorthy; Majumdar, Arun

    2008-01-01

    We report significant thermal conductivity reduction in oxygen-deficient lanthanum-doped strontium titanate (Sr1−xLaxTiO3−δ) films as compared to unreduced strontium titanates. Our experimental results suggest that the oxygen vacancies could have played an important role in the reduction. This could

  15. Pipeline coating inspection in Mexico applying surface electromagnetic technology

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, O.; Mousatov, A.; Nakamura, E.; Villarreal, J.M. [Instituto Mexicano del Petroleo (IMP), Mexico City (Mexico); Shevnin, V. [Moscow State University (Russian Federation); Cano, B. [Petroleos Mexicanos (PEMEX), Mexico City (Mexico)

    2009-07-01

    The main problems in the pipeline systems in Mexico include: extremely aggressive soil characterized by a high clay content and low resistivity, interconnection between several pipes, including electrical contacts of active pipelines with out of service pipes, and short distances between pipes in comparison with their depths which reduce the resolution of coating inspection. The results presented in this work show the efficiency of the Surface Electromagnetic Pipeline Inspection (SEMPI) technology to determine the technical condition of pipelines in situations before mentioned. The SEMPI technology includes two stages: regional and detailed measurements. The regional stage consists of magnetic field measurements along the pipeline using large distances (10 - 100 m) between observation points to delimit zones with damaged coating. For quantitative assessing the leakage and coating resistances along pipeline, additional measurements of voltage and soil resistivity measurements are performed. The second stage includes detailed measurements of the electric field on the pipe intervals with anomalous technical conditions identified in the regional stage. Based on the distribution of the coating electric resistance and the subsoil resistivity values, the delimitation of the zones with different grade of coating quality and soil aggressiveness are performed. (author)

  16. The Greenhouse and Anti-Greenhouse Effects on Titan

    Science.gov (United States)

    McKay, C. P.; Cuzzi, Jeffrey N. (Technical Monitor)

    1994-01-01

    Titan is the largest moon of Saturn and is the only moon in the solar system with a substantial atmosphere. Its atmosphere is mostly made of nitrogen, with a few percent CH4, 0.1% H2 and an uncertain level of Ar (less than 10%). The surface pressure is 1.5 atms and the surface temperature is 95 K, decreasing to 71 at the tropopause before rising to stratospheric temperatures of 180 K. In pressure and composition Titan's atmosphere is the closest twin to Earth's. The surface of Titan remains unknown, hidden by the thick smog layer, but it may be an ocean of liquid methane and ethane. Titan's atmosphere has a greenhouse effect which is much stronger than the Earth's - 92% of the surface warming is due to greenhouse radiation. However an organic smog layer in the upper atmosphere produces an anti-greenhouse effect that cuts the greenhouse warming in half - removing 35% of the incoming solar radiation. Models suggest that during its formation Titan's atmosphere was heated to high temperatures due to accretional energy. This was followed by a cold Triton-like period which gradually warmed to the present conditions. The coupled greenhouse and haze anti-greenhouse may be relevant to recent suggestions for haze shielding of a CH4 - NH3 early atmosphere on Earth or Mars. When the NASA/ESA mission to the Saturn System, Cassini, launches in a few years it will carry a probe that will be sent to the surface of Titan and show us this world that is strange and yet in many ways similar to our own.

  17. Synthesis and characterization of novel lanthanide- and actinide-containing titanates and zircono-titanates; relevance to nuclear waste disposal

    International Nuclear Information System (INIS)

    Shoup, S.L.S.

    1995-08-01

    Before experiments using actinide elements are performed, synthetic routes are tested using lanthanides of comparable ionic radii as surrogates. Compound and solid solution formation in several lanthanide-containing titanate and zircono-titanate systems have been established using X-ray diffraction (XRD) analysis, which helped to define interesting and novel experiments, some of which have been performed and are discussed, for selected actinide elements. The aqueous solubilities of several lanthanide- and actinide-containing compounds, representative of the systems studied, were tested in several leachants, including the WIPP open-quotes Aclose quotes brine, following modified Materials Characterization Center procedures (MCC-3). The WIPP open-quotes Aclose quotes brine is a synthetic substitute for that found in nature at the Waste Isolation Pilot Plant (WIPP) in New Mexico. The concentrations of cerium, used as a surrogate for plutonium, leached by the WIPP open-quotes Aclose quotes brine from all the cerium-containing compounds and solid solutions tested were below the Inductively Coupled Plasma (ICP) atomic emission spectrometry limit of detection (10 ppm) established for cerium in this brine. The concentrations of plutonium leached from the two plutonium-containing solid solutions were less than 1 ppm as determined by gross alpha counting and alpha pulse height analysis. Concentrations of strontium leached by the WIPP brine from stable strontium containing titanate compounds, studied as possible immobilizers of both 90 Sr and actinide elements, were also quite low. These compound and solid solution formation investigations and the aqueous solubility studies suggest that the types of titanate and zircono-titanate compounds and solid solutions studied in this work appear to be useful as host matrices for nuclear waste immobilization

  18. Uncertainty for calculating transport on Titan: A probabilistic description of bimolecular diffusion parameters

    Science.gov (United States)

    Plessis, S.; McDougall, D.; Mandt, K.; Greathouse, T.; Luspay-Kuti, A.

    2015-11-01

    Bimolecular diffusion coefficients are important parameters used by atmospheric models to calculate altitude profiles of minor constituents in an atmosphere. Unfortunately, laboratory measurements of these coefficients were never conducted at temperature conditions relevant to the atmosphere of Titan. Here we conduct a detailed uncertainty analysis of the bimolecular diffusion coefficient parameters as applied to Titan's upper atmosphere to provide a better understanding of the impact of uncertainty for this parameter on models. Because temperature and pressure conditions are much lower than the laboratory conditions in which bimolecular diffusion parameters were measured, we apply a Bayesian framework, a problem-agnostic framework, to determine parameter estimates and associated uncertainties. We solve the Bayesian calibration problem using the open-source QUESO library which also performs a propagation of uncertainties in the calibrated parameters to temperature and pressure conditions observed in Titan's upper atmosphere. Our results show that, after propagating uncertainty through the Massman model, the uncertainty in molecular diffusion is highly correlated to temperature and we observe no noticeable correlation with pressure. We propagate the calibrated molecular diffusion estimate and associated uncertainty to obtain an estimate with uncertainty due to bimolecular diffusion for the methane molar fraction as a function of altitude. Results show that the uncertainty in methane abundance due to molecular diffusion is in general small compared to eddy diffusion and the chemical kinetics description. However, methane abundance is most sensitive to uncertainty in molecular diffusion above 1200 km where the errors are nontrivial and could have important implications for scientific research based on diffusion models in this altitude range.

  19. Barium Titanate Nanoparticles for Biomarker Applications

    International Nuclear Information System (INIS)

    Matar, O; Hondow, N S; Brydson, R M D; Milne, S J; Brown, A P; Posada, O M; Wälti, C; Saunders, M; Murray, C A

    2015-01-01

    A tetragonal crystal structure is required for barium titanate nanoparticles to exhibit the nonlinear optical effect of second harmonic light generation (SHG) for use as a biomarker when illuminated by a near-infrared source. Here we use synchrotron XRD to elucidate the tetragonal phase of commercially purchased tetragonal, cubic and hydrothermally prepared barium titanate (BaTiO 3 ) nanoparticles by peak fitting with reference patterns. The local phase of individual nanoparticles is determined by STEM electron energy loss spectroscopy (EELS), measuring the core-loss O K-edge and the Ti L 3 -edge energy separation of the t 2g , e g peaks. The results show a change in energy separation between the t 2g and e g peak from the surface and core of the particles, suggesting an intraparticle phase mixture of the barium titanate nanoparticles. HAADF-STEM and bright field TEM-EDX show cellular uptake of the hydrothermally prepared BaTiO 3 nanoparticles, highlighting the potential for application as biomarkers. (paper)

  20. Development of partitioning method: adsorption behavior of Sr on titanic acid pelletized with binder

    Energy Technology Data Exchange (ETDEWEB)

    Mizoguchi, Kenichi; Yamaguchi, Isoo; Morita, Yasuji; Yamagishi, Isao; Fujiwara, Takeshi; Kubota, Masumitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-05-01

    The adsorption behavior of Sr was examined with the titanic acid with the binder and with binderless titanic acid. Then the effect of the difference of the neutralizer was also examined. When the initial concentration of Sr was constant, distribution coefficient (Kd) increased with pH after adsorption. At pH 4, Kd decreased in order of the titanic acid neutralized with NH{sub 4}OH solution without the binder > the titanic acid neutralized with NH{sub 4}OH solution and pelletized with the binder > the titanic acid neutralized with KOH solution and pelletized with the binder. At pH 6, Kd decreased with increasing the concentration of Sr in the solution, but the decreasing tendency of Kd for each titanic acid was the same. Adsorption kinetics was examined with titanic acids neutralized with NH{sub 4}OH solution, keeping the initial concentration of Sr and the initial pH constant. It took about one hour to reach Kd of 100mL/g for the titanic acid without the binder but over 10 hours for the titanic acid pelletized with the binder. It was confirmed that by pelletizing titanic acid with the binder, Kd of Sr became small and it took very long time to reach the adsorption equilibrium. However, by sufficient conditioning with water of the titanic acid pelletized with the binder, 1) it took about half time of titanic acid without conditioning to reach Kd of 100mL/g, 2) after 24 hours mixing, Kd for the titanic acid pelletized with the binder was almost equal to that for the titanic acid without the binder, 3) apparent ion exchange capacity obtained through a column test became over about 1meq/g. (J.P.N.)

  1. Development of partitioning method: adsorption behavior of Sr on titanic acid pelletized with binder

    International Nuclear Information System (INIS)

    Mizoguchi, Kenichi; Yamaguchi, Isoo; Morita, Yasuji; Yamagishi, Isao; Fujiwara, Takeshi; Kubota, Masumitsu

    1998-05-01

    The adsorption behavior of Sr was examined with the titanic acid with the binder and with binderless titanic acid. Then the effect of the difference of the neutralizer was also examined. When the initial concentration of Sr was constant, distribution coefficient (Kd) increased with pH after adsorption. At pH 4, Kd decreased in order of the titanic acid neutralized with NH 4 OH solution without the binder > the titanic acid neutralized with NH 4 OH solution and pelletized with the binder > the titanic acid neutralized with KOH solution and pelletized with the binder. At pH 6, Kd decreased with increasing the concentration of Sr in the solution, but the decreasing tendency of Kd for each titanic acid was the same. Adsorption kinetics was examined with titanic acids neutralized with NH 4 OH solution, keeping the initial concentration of Sr and the initial pH constant. It took about one hour to reach Kd of 100mL/g for the titanic acid without the binder but over 10 hours for the titanic acid pelletized with the binder. It was confirmed that by pelletizing titanic acid with the binder, Kd of Sr became small and it took very long time to reach the adsorption equilibrium. However, by sufficient conditioning with water of the titanic acid pelletized with the binder, 1) it took about half time of titanic acid without conditioning to reach Kd of 100mL/g, 2) after 24 hours mixing, Kd for the titanic acid pelletized with the binder was almost equal to that for the titanic acid without the binder, 3) apparent ion exchange capacity obtained through a column test became over about 1meq/g. (J.P.N.)

  2. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  3. Aerosol chemistry in Titan's ionosphere: simultaneous growth and etching processes

    Science.gov (United States)

    Carrasco, Nathalie; Cernogora, Guy; Jomard, François; Etcheberry, Arnaud; Vigneron, Jackie

    2016-10-01

    Since the Cassini-CAPS measurements, organic aerosols are known to be present and formed at high altitudes in the diluted and partially ionized medium that is Titan's ionosphere [1]. This unexpected chemistry can be further investigated in the laboratory with plasma experiments simulating the complex ion-neutral chemistry starting from N2-CH4 [2]. Two sorts of solid organic samples can be produced in laboratory experiments simulating Titan's atmospheric reactivity: grains in the volume and thin films on the reactor walls. We expect that grains are more representative of Titan's atmospheric aerosols, but films are used to provide optical indices for radiative models of Titan's atmosphere.The aim of the present study is to address if these two sorts of analogues are chemically equivalent or not, when produced in the same N2-CH4 plasma discharge. The chemical compositions of both these materials are measured by using elemental analysis, XPS analysis and Secondary Ion Mass Spectrometry. We find that films are homogeneous but significantly less rich in nitrogen and hydrogen than grains produced in the same experimental conditions. This surprising difference in their chemical compositions is explained by the efficient etching occurring on the films, which stay in the discharge during the whole plasma duration, whereas the grains are ejected after a few minutes [3]. The impact for our understanding of Titan's aerosols chemical composition is important. Our study shows that chemical growth and etching process are simultaneously at stake in Titan's ionosphere. The more the aerosols stay in the ionosphere, the more graphitized they get through etching process. In order to infer Titan's aerosols composition, our work highlights a need for constraints on the residence time of aerosols in Titan's ionosphere. [1] Waite et al. (2009) Science , 316, p. 870[2] Szopa et al. (2006) PSS, 54, p. 394[3] Carrasco et al. (2016) PSS, 128, p. 52

  4. Plasma environment of Titan: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-05-01

    Full Text Available Titan possesses a dense atmosphere, consisting mainly of molecular nitrogen. Titan's orbit is located within the Saturnian magnetosphere most of the time, where the corotating plasma flow is super-Alfvénic, yet subsonic and submagnetosonic. Since Titan does not possess a significant intrinsic magnetic field, the incident plasma interacts directly with the atmosphere and ionosphere. Due to the characteristic length scales of the interaction region being comparable to the ion gyroradii in the vicinity of Titan, magnetohydrodynamic models can only offer a rough description of Titan's interaction with the corotating magnetospheric plasma flow. For this reason, Titan's plasma environment has been studied by using a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas a completely kinetic approach is used to cover ion dynamics. The calculations are performed on a curvilinear simulation grid which is adapted to the spherical geometry of the obstacle. In the model, Titan's dayside ionosphere is mainly generated by solar UV radiation; hence, the local ion production rate depends on the solar zenith angle. Because the Titan interaction features the possibility of having the densest ionosphere located on a face not aligned with the ram flow of the magnetospheric plasma, a variety of different scenarios can be studied. The simulations show the formation of a strong magnetic draping pattern and an extended pick-up region, being highly asymmetric with respect to the direction of the convective electric field. In general, the mechanism giving rise to these structures exhibits similarities to the interaction of the ionospheres of Mars and Venus with the supersonic solar wind. The simulation results are in agreement with data from recent Cassini flybys.

  5. Effects of hydrothermal post-treatment on microstructures and morphology of titanate nanoribbons

    International Nuclear Information System (INIS)

    Yu Huogen; Yu Jiaguo; Cheng Bei; Zhou Minghua

    2006-01-01

    Titanate nanoribbons were prepared via a hydrothermal treatment of rutile-type TiO 2 powders in a 10 M NaOH solution at 200 deg. C for 48 h. The as-prepared titanate nanoribbons were then hydrothermally post-treated at 150 deg. C for 12-36 h. The titanate nanoribbons before and after hydrothermal post-treatment were characterized with FESEM, XRD, TEM, UV-VIS and nitrogen adsorption-desorption isotherms. The results showed that the hydrothermal post-treatment not only promoted the phase transformation from titanate to anatase TiO 2 , but also was beneficial to the removal of Na + ions remained in the titanate nanoribbons. After hydrothermal post-treatment, the TiO 2 samples retained the one-dimensional structure feature of the titanate nanoribbons and showed an obvious increase in the specific surface area and the pore volume

  6. Use of titanates in decontamination of defense waste

    International Nuclear Information System (INIS)

    Dosch, R.G.

    1978-06-01

    Sodium titanate, an inorganic ion exchange material, has been evaluated for use in a process to remove strontium from Defense Waste or other high-sodium, caustic solutions. Distribution coefficients on the order of 10 5 were observed at sub part per million concentrations of Sr, and the effects of other cation impurities and complexants in the waste were investigated. The preparation and general chemical properties of the exchange material are discussed. This information was used in developing a commercial source which has since supplied a 200 kg batch of the material for evaluation. In column ion exchange experiments with 85 Sr-doped simulated waste, decontamination factors of 500 or greater were observed in the first 2000 to 3500 bed volumes of effluent, depending on the impurities in the simulant. A -40 to +130 mesh range of sodium titanate powder was used as the baseline material, but a study to produce alternate forms of the titanate was carried in parallel. This has resulted in two materials which appear promising with respect to both simplification of handling and chemical properties. One of the materials is an agglomerated form of the titanate formed by extrusion pelletizing using water as a binder, and the second is a macroreticular organic anion resin which was loaded with 30 to 40% (by weight) of sodium titanate. The results of initial testing of these materials are discussed

  7. Multi-wavelength search for complex molecules in Titan's Atmosphere

    Science.gov (United States)

    Nixon, C. A.; Cordiner, M. A.; Greathouse, T. K.; Richter, M.; Kisiel, Z.; Irwin, P. G.; Teanby, N. A.; Kuan, Y. J.; Charnley, S. B.

    2017-12-01

    Titan's atmosphere is one of the most complex astrochemical environments known: the photochemistry of methane and nitrogen, induced by solar UV and Saturn magnetospheric electron impacts, creates a bonanza of organic molecules like no other place in the solar system. Cassini has unveiled the first glimpses of Titan's chemical wonderland, but many gaps remain. In particular, interpreting the mass spectra of Titan's upper atmosphere requires external knowledge, to disentangle the signature of molecules from their identical-mass brethren. Cassini infrared spectroscopy with CIRS has helped to some extent, but is also limited by low spectral resolution. Potentially to the rescue, comes high-resolution spectroscopy from the Earth at infrared and sub-millimeter wavelengths, where molecules exhibit vibrational and rotational transitions respectively. In this presentation, we describe the quest to make new, unique identifications of large molecules in Titan's atmosphere, focusing specifically on cyclic molecules including N-heterocycles. This molecular family is of high astrobiological significance, forming the basic ring structure for DNA nucleobases. We present the latest spectroscopic observations of Titan from ALMA and NASA's IRTF telescope, discussing present findings and directions for future work.

  8. Calorimetric measurements on hafnium titanate

    International Nuclear Information System (INIS)

    Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.

    2012-01-01

    Owing to its desirable nuclear and mechanical properties such as good absorption cross-section for thermal neutrons (105 barns), hafnium titanate (HfTiO 4 ) finds application as control rods for nuclear reactors. An accurate knowledge of the thermo physical properties of this material is necessary for design of control rod and for modeling its performance. Heat capacity is an important thermodynamic property that determines the temperature dependent variation of all other thermodynamic properties. Hence enthalpy increments of hafnium titanate (HfTiO 4 ) were measured in the temperature range 803-1663 K by employing the method of inverse drop calorimetry using high temperature differential calorimeter

  9. Antibacterial Properties of Titanate Nano fiber Thin Films Formed on a Titanium Plate

    International Nuclear Information System (INIS)

    Yada, M.; Inoue, Y.; Morita, T.; Torikai, T.; Watari, T.; Noda, I.; Hotokebuchi, T.

    2013-01-01

    A sodium titanate nano fiber thin film and a silver nanoparticle/silver titanate nano fiber thin film formed on the surface of a titanium plate exhibited strong antibacterial activities against methicillin-resistant Staphylococcus aureus, which is one of the major bacteria causing in-hospital infections. Exposure of the sodium titanate nano fiber thin film to ultraviolet rays generated a high antibacterial activity due to photo catalysis and the sodium titanate nano fiber thin film immediately after its synthesis possessed a high antibacterial activity even without exposure to ultraviolet rays. Elution of silver from the silver nanoparticle/silver titanate nano fiber thin film caused by the silver ion exchange reaction was considered to contribute substantially to the strong antibacterial activity. The titanate nano fiber thin films adhered firmly to titanium. Therefore, these titanate nano fiber thin film/titanium composites will be extremely useful as implant materials that have excellent antibacterial activities.

  10. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  11. Acetylene on Titan

    Science.gov (United States)

    Singh, Sandeep; McCord, Thomas B.; Combe, Jean-Philippe; Rodriguez, Sebastien; Cornet, Thomas; Le Mouélic, Stéphane; Clark, Roger Nelson; Maltagliati, Luca; Chevrier, Vincent

    2016-10-01

    Saturn's moon Titan possesses a thick atmosphere that is mainly composed of N2 (98%), CH4 (2 % overall, but 4.9% close to the surface) and less than 1% of minor species, mostly hydrocarbons [1]. A dissociation of N2 and CH4 forms complex hydrocarbons in the atmsophere and acetylene (C2H2) and ethane (C2H6) are produced most abundently. Since years, C2H2 has been speculated to exist on the surface of Titan based on its high production rate in the stratosphere predicted by photochemical models [2,3] and from its detection as trace gas sublimated/evaporated from the surface after the landing of the Huygens probe by the Gas Chromatograph Mass Spectrometer (GCMS) [1]. Here we show evidence of acetylene (C2H2) on the surface of Titan by detecting absorption bands at 1.55 µm and 4.93 µm using Cassini Visual and Infrared Mapping Spectrometer (VIMS) [4] at equatorial areas of eastern Shangri-La, and Fensal-Aztlan/Quivira.An anti-correlation of absorption band strength with albedo indicates greater concentrations of C2H2 in the dark terrains, such as sand dunes and near the Huygens landing site. The specific location of the C2H2 detections suggests that C2H2 is mobilized by surface processes, such as surface weathering by liquids through dissolution/evaporation processes.References:[1]Niemann et al., Nature 438, 779-784 (2005).[2]Lavvas et al., Planetary and Space Science 56, 67 - 99 (2008).[3]Lavvas et al., Planetary and Space Science 56, 27 - 66 (2008).[4] Brown et al., The Cassini-Huygens Mission 111-168 (Springer, 2004).

  12. Activation and waste disposal of the TITAN RFP [reversed-field-pinch] reactors

    International Nuclear Information System (INIS)

    Cheng, E.T.; Conn, R.W.

    1988-01-01

    The TITAN-I lithium self-cooled and TITAN-II aqueous lithium nitrate solution-cooled fusion reactors are based on the reversed-field-pinch (RFP) toroidal confinement concept and operate at high power density with an 18.1 MW/m 2 neutron wall loading. These designs were analyzed to study the activation and waste disposal aspects of such high-power density reactors. It was found that because of the use of V-3Ti-1Si (TITAN-I) and reduced activation ferritic steel (TITAN-II) as structural alloys for the first wall, blanket, reflector, and shield components, all the TITAN components except the divertor collector plates can be classified as shallow-land burial (10CFR61 Class C or better) nuclear waste for disposal, provided that the impurity elements, niobium and molybdenum, can be controlled below about 1 and 0.3 appm levels, respectively. The average annual disposal masses were estimated to be 150 and 96 tonnes, respectively, for the 1,000 MW TITAN-I and TITAN-II reactors. This corresponds to about 11% of the total mass in the fusion power core of both reactors. The divertor collector plates are fabricated with tungsten because of its low particle sputtering properties. These divertor collector plates in the TITAN-I reactor will be qualified as Class C waste after 18.1 MW-y/m 2 operation. The waste disposal rating of the divertor collector plates in the TITAN-II reactor, however, is estimated to be a factor of 4 higher than allowed for Class C disposal, because of the soft neutron spectrum in the beryllium environment. The annual disposal mass of this non-Class C waste is 0.35 tons, about 0.04% of the average annual discharge mass for the TITAN-II reactor. An additional 74 m 3 annual discharge of Class C waste containing 14 C may be needed for the TITAN-II reactor because of the use of nitrate salt in the aqueous coolant as the tritium breeder. 13 refs., 6 tabs

  13. Production and global transport of Titan's sand particles

    Science.gov (United States)

    Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; Arnold, Karl; Chandler, Clayton

    2015-06-01

    Previous authors have suggested that Titan's individual sand particles form by either sintering or by lithification and erosion. We suggest two new mechanisms for the production of Titan's organic sand particles that would occur within bodies of liquid: flocculation and evaporitic precipitation. Such production mechanisms would suggest discrete sand sources in dry lakebeds. We search for such sources, but find no convincing candidates with the present Cassini Visual and Infrared Mapping Spectrometer coverage. As a result we propose that Titan's equatorial dunes may represent a single, global sand sea with west-to-east transport providing sources and sinks for sand in each interconnected basin. The sand might then be transported around Xanadu by fast-moving Barchan dune chains and/or fluvial transport in transient riverbeds. A river at the Xanadu/Shangri-La border could explain the sharp edge of the sand sea there, much like the Kuiseb River stops the Namib Sand Sea in southwest Africa on Earth. Future missions could use the composition of Titan's sands to constrain the global hydrocarbon cycle.

  14. Exploring inner structure of Titan's dunes from Cassini Radar observations

    Science.gov (United States)

    Sharma, P.; Heggy, E.; Farr, T. G.

    2013-12-01

    Linear dunes discovered in the equatorial regions of Titan by the Cassini-Huygens mission are morphologically very similar to many terrestrial linear dune fields. These features have been compared with terrestrial longitudinal dune fields like the ones in Namib desert in western Africa. This comparison is based on the overall parallel orientation of Titan's dunes to the predominant wind direction on Titan, their superposition on other geomorphological features and the way they wrap around topographic obstacles. Studying the internal layering of dunes has strong implications in understanding the hypothesis for their origin and evolution. In Titan's case, although the morphology of the dunes has been studied from Cassini Synthetic Aperture Radar (SAR) images, it has not been possible to investigate their internal structure in detail as of yet. Since no radar sounding data is available for studying Titan's subsurface yet, we have developed another technique to examine the inner layering of the dunes. In this study, we utilize multiple complementary radar datasets, including radar imaging data for Titan's and Earth's dunes and Ground Penetrating Radar (GPR)/radar sounding data for terrestrial dunes. Based on dielectric mixing models, we suggest that the Cassini Ku-band microwaves should be able to penetrate up to ~ 3 m through Titan's dunes, indicating that the returned radar backscatter signal would include contributions from both surface and shallow subsurface echoes. This implies that the shallow subsurface properties can be retrieved from the observed radar backscatter (σ0). In our analysis, the variation of the radar backscatter as a function of dune height is used to provide an insight into the layering in Titan's dunes. We compare the variation of radar backscatter with elevation over individual dunes on Titan and analogous terrestrial dunes in three sites (Great Sand Sea, Siwa dunes and Qattaniya dunes) in the Egyptian Sahara. We observe a strong, positive

  15. ATOMIC CARBON IN THE UPPER ATMOSPHERE OF TITAN

    International Nuclear Information System (INIS)

    Zhang, X.; Yung, Y. L.; Ajello, J. M.

    2010-01-01

    The atomic carbon emission C I line feature at 1657 A ( 3 P 0 J - 3 P J ) in the upper atmosphere of Titan is first identified from the airglow spectra obtained by the Cassini Ultra-violet Imaging Spectrograph. A one-dimensional photochemical model of Titan is used to study the photochemistry of atomic carbon on Titan. Reaction between CH and atomic hydrogen is the major source of atomic carbon, and reactions with hydrocarbons (C 2 H 2 and C 2 H 4 ) are the most important loss processes. Resonance scattering of sunlight by atomic carbon is the dominant emission mechanism. The emission intensity calculations based on model results show good agreement with the observations.

  16. Titan's icy scar

    Science.gov (United States)

    Griffith, C. A.; Penteado, P. F.; Turner, J. D.; Neish, C. D.; Mitri, G.; Montiel, M. J.; Schoenfeld, A.; Lopes, R. M. C.

    2017-09-01

    We conduct a Principal Components Analysis (PCA) of Cassini/VIMS [1] infrared spectral windows to identify and quantify weak surface features, with no assumptions on the haze and surface characteris- tics. This study maps the organic sediments, supplied by past atmospheres, as well as ice-rich regions that constitute Titan's bedrock.

  17. Ion Irradiation Damage in Zirconate and Titanate Ceramics for Pu Disposition

    International Nuclear Information System (INIS)

    Stewart, Martin W.; Begg, Bruce D.; Finnie, K.; Colella, Michael; Li, H.; McLeod, Terry; Smith, Katherine L.; Zhang, Zhaoming; Weber, William J.; Thevuthasan, Suntharampillai

    2004-01-01

    In this paper, we discuss the effect of ion irradiation on pyrochlore-rich titanate and defect-fluorite zirconate ceramics designed for plutonium immobilization. Samples, with Ce as an analogue for Pu, were made via oxide routes and consolidated by cold-pressing and sintering. Ion irradiation damage was carried out with 2 MeV Au2+ ions to a fluence of 5 ions nm-2 in the accelerator facilities within the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. Irradiated and non-irradiated samples were examined by x-ray diffraction, scanning and transmission electron microscopy, x-ray photoelectron and infrared spectroscopy, and spectroscopic ellipsometry. Samples underwent accelerated leach testing at pH 1.75 (nitric acid) at 90 C for 28 days. The zirconate samples were more ion-irradiation damage resistant than the titanate samples, showing little change after ion-irradiation whereas the titanate samples formed an amorphous surface layer ∼ 500 nm thick. While all samples had high aqueous durability, the titanate leach rate was ∼ 5 times that of the zirconate. The ion-irradiation increased the leach rate of the titanate without impurities by ∼ 5 times. The difference in the leach rates between irradiated and unirradiated zirconate samples is small. However, the zirconates were less able to incorporate impurities than the titanate ceramics and required higher sintering temperatures, ∼ 1500 C compared to 1350 C for the titanates.

  18. Description of tritium release from lithium titanate at constant temperature

    Energy Technology Data Exchange (ETDEWEB)

    Pena, L; Lagos, S; Jimenez, J; Saravia, E [Comision Chilena de Energia Nuclear, Santiago (Chile)

    1998-03-01

    Lithium Titanate Ceramics have been prepared by the solid-state route, pebbles and pellets were fabricated by extrusion and their microstructure was characterized in our laboratories. The ceramic material was irradiated in the La Reina Reactor, RECH-1. A study of post-irradiation annealing test, was performed measuring Tritium release from the Lithium Titanate at constant temperature. The Bertone`s method modified by R. Verrall is used to determine the parameters of Tritium release from Lithium Titanate. (author)

  19. Titan's cold case files - Outstanding questions after Cassini-Huygens

    Science.gov (United States)

    Nixon, C. A.; Lorenz, R. D.; Achterberg, R. K.; Buch, A.; Coll, P.; Clark, R. N.; Courtin, R.; Hayes, A.; Iess, L.; Johnson, R. E.; Lopes, R. M. C.; Mastrogiuseppe, M.; Mandt, K.; Mitchell, D. G.; Raulin, F.; Rymer, A. M.; Todd Smith, H.; Solomonidou, A.; Sotin, C.; Strobel, D.; Turtle, E. P.; Vuitton, V.; West, R. A.; Yelle, R. V.

    2018-06-01

    The entry of the Cassini-Huygens spacecraft into orbit around Saturn in July 2004 marked the start of a golden era in the exploration of Titan, Saturn's giant moon. During the Prime Mission (2004-2008), ground-breaking discoveries were made by the Cassini orbiter including the equatorial dune fields (flyby T3, 2005), northern lakes and seas (T16, 2006), and the large positive and negative ions (T16 & T18, 2006), to name a few. In 2005 the Huygens probe descended through Titan's atmosphere, taking the first close-up pictures of the surface, including large networks of dendritic channels leading to a dried-up seabed, and also obtaining detailed profiles of temperature and gas composition during the atmospheric descent. The discoveries continued through the Equinox Mission (2008-2010) and Solstice Mission (2010-2017) totaling 127 targeted flybys of Titan in all. Now at the end of the mission, we are able to look back on the high-level scientific questions from the start of the mission, and assess the progress that has been made towards answering these. At the same time, new scientific questions regarding Titan have emerged from the discoveries that have been made. In this paper we review a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan's deep interior to the exosphere. Our intention is to help formulate the science goals for the next generation of planetary missions to Titan, and to stimulate new experimental, observational and theoretical investigations in the interim.

  20. Latitudinal and altitudinal controls of Titan's dune field morphometry

    Science.gov (United States)

    Le Gall, A.; Hayes, A. G.; Ewing, R.; Janssen, M. A.; Radebaugh, J.; Savage, C.; Encrenaz, P.; the Cassini Radar Team

    2012-01-01

    Dune fields dominate ˜13% of Titan's surface and represent an important sink of carbon in the methane cycle. Herein, we discuss correlations in dune morphometry with altitude and latitude. These correlations, which have important implications in terms of geological processes and climate on Titan, are investigated through the microwave electromagnetic signatures of dune fields using Cassini radar and radiometry observations. The backscatter and emissivity from Titan's dune terrains are primarily controlled by the amount of interdune area within the radar footprint and are also expected to vary with the degree of the interdunal sand cover. Using SAR-derived topography, we find that Titan's main dune fields (Shangri-La, Fensal, Belet and Aztlan) tend to occupy the lowest elevation areas in Equatorial regions occurring at mean elevations between ˜-400 and ˜0 m (relative to the geoid). In elevated dune terrains, we show a definite trend towards a smaller dune to interdune ratio and possibly a thinner sand cover in the interdune areas. A similar correlation is observed with latitude, suggesting that the quantity of windblown sand in the dune fields tends to decrease as one moves farther north. The altitudinal trend among Titan's sand seas is consistent with the idea that sediment source zones most probably occur in lowlands, which would reduce the sand supply toward elevated regions. The latitudinal preference could result from a gradual increase in dampness with latitude due to the asymmetric seasonal forcing associated with Titan's current orbital configuration unless it is indicative of a latitudinal preference in the sand source distribution or wind transport capacity.

  1. ALMA observations of Titan's atmospheric chemistry and seasonal variation

    Science.gov (United States)

    Cordiner, Martin

    2017-04-01

    Titan is the largest moon of Saturn, with a thick (1.45 bar) atmosphere composed primarily of molecular nitrogen and methane. Photochemistry in Titan's upper atmosphere results in the production of a wide range of organic molecules, including hydrocarbons, nitriles and aromatics, some of which could be of pre-biotic relevance. Thus, we obtain insights into the possible molecular inventories of primitive (reducing) planetary atmospheres. Titan's atmosphere also provides a unique laboratory for testing our understanding of fundamental processes involving the chemistry and spectroscopy of complex organic molecules. In this talk, results will be presented from our studies using the Atacama Large Millimeter/submillimeter Array (ALMA) during the period 2012-2015, focussing in particular on the detection and mapping of emission from various nitrile species. By combining data from multiple ALMA observations, our spectra have reached an unprecedented sensitivity level, enabling the first spectroscopic detection and mapping of C2H3CN (vinyl cyanide) on Titan. Liquid-phase simulations of Titan's seas indicate that vinyl cyanide molecules could combine to form vesicle membranes (similar to the cells of terrestrial biology), and the astrobiological implications of this discovery will be discussed. Furthermore, ALMA observations provide instantaneous snapshot mapping of Titan's entire Earth-facing hemisphere, for gases inaccessible to previous instruments. Combined with complementary data obtained from the Cassini Saturn orbiter, as well as theoretical models and laboratory studies, our observed, seasonally variable, spatially resolved abundance patterns are capable of providing new insights into photochemical production and transport in primitive planetary atmospheres in the Solar System and beyond.

  2. Cross-poling textures in a lead zirconate titanate piezoelectric material

    International Nuclear Information System (INIS)

    Wan, Shan; Bowman, Keith J.

    2000-01-01

    Tetragonal ferroelectric materials are polarized to induce the anisotropy necessary for the piezoelectric effect. This poling of the material is inherently an orientation process. Pole figure texture measurements of poling and cross-poling in a lead zirconate titanate Navy VI material show domain motion. The resulting axisymmetric and three-dimensional textures demonstrate the contribution of 90 degree sign domain motion to piezoelectricity. Cross-poling results in strong orientations with lower applied fields than in the initial poling steps. (c) 2000 Materials Research Society

  3. Lunar occultation of Saturn. II - The normal reflectance of Rhea, Titan, and Iapetus

    Science.gov (United States)

    Elliot, J. L.; Dunham, E. W.; Veverka, J.; Goguen, J.

    1978-01-01

    An inversion procedure to obtain the reflectance of the central region of a satellite's disk from lunar occultation data is presented. The scheme assumes that the limb darkening of the satellite depends only on the radial distance from the center of the disk. Given this assumption, normal reflectances can be derived that are essentially independent of the limb darkening and the diameter of the satellite. The procedure has been applied to our observations of the March 1974 lunar occultation of Tethys, Dione, Rhea, Titan, and Iapetus. In the V passband we derive the following normal reflectances: Rhea (0.97 plus or minus 0.20), Titan (0.24 plus or minus 0.03), Iapetus, bright face (0.60 plus or minus 0.14). For Tethys and Dione the values derived have large uncertainties, but are consistent with our result for Rhea.

  4. Crater topography on Titan: Implications for landscape evolution

    Science.gov (United States)

    Neish, C.; Kirk, R.; Lorenz, R.; Bray, V.; Schenk, P.; Stiles, B.; Turtle, E.; Cassini Radar Team

    2012-04-01

    Unique among the icy satellites, Titan’s surface shows evidence for extensive modification by fluvial and aeolian erosion, which act to change the topography of its surface over time. Quantifying the extent of this landscape evolution is difficult, since the original, ‘non-eroded’ surface topography is generally unknown. However, fresh craters on icy satellites have a well-known shape and morphology, which has been determined from extensive studies on the airless worlds of the outer solar system (Schenk et al., 2004). By comparing the topography of craters on Titan to similarly sized, pristine analogues on airless bodies, we can obtain one of the few direct measures of the amount of erosion that has occurred on Titan. Cassini RADAR has imaged >30% of the surface of Titan, and more than 60 potential craters have been identified in this data set (Wood et al., 2010; Neish and Lorenz, 2012). Topographic information for these craters can be obtained from a technique known as ‘SARTopo’, which estimates surface heights by comparing the calibration of overlapping synthetic aperture radar (SAR) beams (Stiles et al., 2009). We present topography data for several craters on Titan, and compare the data to similarly sized craters on Ganymede, for which topography has been extracted from stereo-derived digital elevation models (Bray et al., 2012). We find that the depths of craters on Titan are generally within the range of depths observed on Ganymede, but several hundreds of meters shallower than the average (Fig. 1). A statistical comparison between the two data sets suggests that it is extremely unlikely that Titan’s craters were selected from the depth distribution of fresh craters on Ganymede, and that is it much more probable that the relative depths of Titan are uniformly distributed between ‘fresh’ and ‘completely infilled’. This is consistent with an infilling process that varies linearly with time, such as aeolian infilling. Figure 1: Depth of

  5. A PMMA coated PMN–PT single crystal resonator for sensing chemical agents

    International Nuclear Information System (INIS)

    Frank, Michael; Kassegne, Sam; Moon, Kee S

    2010-01-01

    A highly sensitive lead magnesium niobate–lead titanate (PMN–PT) single crystal resonator coated with a thin film of polymethylmethacrylate (PMMA) useful for detecting chemical agents such as acetone, methanol, and isopropyl alcohol is presented. Swelling of the cured PMMA polymer layer in the presence of acetone, methanol, and isopropyl alcohol vapors is sensed as a mass change transduced to an electrical signal by the PMN–PT thickness shear mode sensor. Frequency change in the PMN–PT sensor is demonstrated to vary according to the concentration of the chemical vapor present within the sensing chamber. For acetone, the results indicate a frequency change more than 6000 times greater than that which would be expected from a quartz crystal microbalance coated with PMMA. This study is the first of its kind to demonstrate vapor loading of adsorbed chemical agents onto a polymer coated PMN–PT resonator

  6. Investigation on corrosion resistance of metal superficially modified with alkoxy titanates

    International Nuclear Information System (INIS)

    Yao Kangde; Song Shizhe; Shen Ningxiang

    1991-01-01

    A study has been made in order to determine corrosion protection performance of alkoxy titanate modified iron in a 3% NaCl solution. The effectiveness of alkoxy titanates as corrosion retarders for chloride environments is confirmed by both stepped potential sweep technique and electrochemical impedance spectroscopy (EIS). Ion microanalysis (IMA) depth profiles are used to elucidate the corrosion inhibitive action of different alkoxy titanate. (orig.)

  7. Cassini/CIRS Observations of Water Vapor in Titan's Stratosphere

    Science.gov (United States)

    Bjoraker, Gordon L.; Achterberg, R. K.; Anderson, C. M.; Samuelson, R. E.; Carlson, R. C.; Jennings, D. E.

    2008-01-01

    The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained spectra of Titan during most of the 44 flybys of the Cassini prime mission. Water vapor on Titan was first detected using whole-disk observations from the Infrared Space Observatory (Coustenis et al 1998, Astron. Astrophys. 336, L85-L89). CIRS data permlt the retrieval of the latitudinal variation of water on Titan and some limited information on its vertical profile. Emission lines of H2O on Titan are very weak in the CIRS data. Thus, large spectral averages as well as improvements in calibration are necessary to detect water vapor. Water abundances were retrieved in nadir spectra at 55 South, the Equator, and at 19 North. Limb spectra of the Equator were also modeled to constrain the vertical distribution of water. Stratospheric temperatures in the 0.5 - 4.0 mbar range were obtained by inverting spectra of CH4 in the v4 band centered at 1304/cm. The temperature in the lower stratosphere (4 - 20 mbar) was derived from fitting pure rotation lines of CH4 between 80 and 160/cm. The origin of H2O and CO2 is believed to be from the ablation of micrometeorites containing water ice, followed by photochemistry. This external source of water originates either within the Saturn system or from the interplanetary medium. Recently, Horst et al (J. Geophys. Res. 2008, in press) developed a photochemical model of Titan in which there are two external sources of oxygen. Oxygen ions (probably from Enceladus) precipitate into Titan's atmosphere to form CO at very high altitudes (1100 km). Water ice ablation at lower altitudes (700 km) forms H2O and subsequent chemistry produces CO2. CIRS measurements of CO, CO2, and now of H2O will provide valuable constraints to these photochemical models and - improve our understanding of oxygen chemistry on Titan.

  8. Lightning generation in Titan due to the electrical self-polarization properties of Methane

    Science.gov (United States)

    Quintero, A.; Falcón, N.

    2009-05-01

    We describe an electrical charge process in Titan's thunderclouds, due to the self-polarization properties or pyroelectricity of methane, which increases the internal electric field in thunderclouds and facilitates the charge generation and separation processes. Microphysics that generates lightning flashes is associated with the physical and chemical properties of the local atmosphere, so methane could be the principal agent of the electrical activity because of its great concentration in Titan's atmosphere. Besides, Titan's electrical activity should not be very influenced by Saturn's magnetosphere because lightning occurs at very low altitude above Titan's surface, compared with the greater distance of Saturn's magnetosphere and Titan's troposphere. Using an electrostatic treatment, we calculate the internal electric field of Titan's thunderclouds due to methane's pyroelectrical properties, 7.05×10^11 Vm^-1; and using the telluric capacitor approximation for thunderclouds, we calculate the total charge obtained for a typical Titan thundercloud, 2.67×10^9 C. However, it is not right to use an electrostatic treatment because charge times are very fast due to the large methane concentration in Titan's clouds and the life time of thunderclouds is very low (around 2 hours). We consider a time dependent mechanism, employing common Earth atmospheric approaches, because of the similitude in chemical composition of both atmospheres (mainly nitrogen), so the typical charge of a thundercloud in Titan should reach between 20 C to 40 C, like on Earth. We obtain that lightning occurs with a frequency between 2 and 6 KHz. In Titan's atmosphere, methane concentration is higher than on Earth, and atmospheric electrical activity is stronger, so this model could be consistent with the observed phenomenology.

  9. Titan: a laboratory for prebiological organic chemistry

    Science.gov (United States)

    Sagan, C.; Thompson, W. R.; Khare, B. N.

    1992-01-01

    When we examine the atmospheres of the Jovian planets (Jupiter, Saturn, Uranus, and Neptune), the satellites in the outer solar system, comets, and even--through microwave and infrared spectroscopy--the cold dilute gas and grains between the stars, we find a rich organic chemistry, presumably abiological, not only in most of the solar system but throughout the Milky Way galaxy. In part because the composition and surface pressure of the Earth's atmosphere 4 x 10(9) years ago are unknown, laboratory experiments on prebiological organic chemistry are at best suggestive; but we can test our understanding by looking more closely at the observed extraterrestrial organic chemistry. The present Account is restricted to atmospheric organic chemistry, primarily on the large moon of Saturn. Titan is a test of our understanding of the organic chemistry of planetary atmospheres. Its atmospheric bulk composition (N2/CH4) is intermediate between the highly reducing (H2/He/CH4/NH3/H2O) atmospheres of the Jovian planets and the more oxidized (N2/CO2/H2O) atmospheres of the terrestrial planets Mars and Venus. It has long been recognized that Titan's organic chemistry may have some relevance to the events that led to the origin of life on Earth. But with Titan surface temperatures approximately equal to 94 K and pressures approximately equal to 1.6 bar, the oceans of the early Earth have no ready analogue on Titan. Nevertheless, tectonic events in the water ice-rich interior or impact melting and slow re-freezing may lead to an episodic availability of liquid water. Indeed, the latter process is the equivalent of a approximately 10(3)-year-duration shallow aqueous sea over the entire surface of Titan.

  10. Theoretical Calculations on Sediment Transport on Titan, and the Possible Production of Streamlined Forms

    Science.gov (United States)

    Burr, D. M.; Emery, J. P.; Lorenz, R. D.

    2005-01-01

    The Cassini Imaging Science System (ISS) has been returning images of Titan, along with other Saturnian satellites. Images taken through the 938 nm methane window see down to Titan's surface. One of the purposes of the Cassini mission is to investigate possible fluid cycling on Titan. Lemniscate features shown recently and radar evidence of surface flow prompted us to consider theoretically the creation by methane fluid flow of streamlined forms on Titan. This follows work by other groups in theoretical consideration of fluid motion on Titan's surface.

  11. Adsorption of carbon dioxide on TEPA-modified TiO_2/titanate composite nano-rods

    International Nuclear Information System (INIS)

    Kapica-Kozar, Joanna; Michalkiewicz, Beata; Wrobel, Rafal J.; Mozia, Sylwia; Pirog, Ewa; Usiak-Nejman, Ewelina K.; Serafin, Jaroslaw; Morawski, Antoni W.; Narkiewicz, Urszula

    2017-01-01

    A titanate-TiO_2 composite was obtained through hydrothermal treatment of TiO_2 in KOH solution. The presence of a titanate phase was confirmed by X-ray diffraction (XRD), whereas scanning electron microscopy (SEM) measurements showed the porous nano-rod structure of the material. The obtained nano-rods were treated with tetra-ethylene-pentamine (TEPA). Such synthesized sorbents were applied for CO_2 removal. The CO_2 capacity under a pressure of 1 bar and at 80 C was 0.47, 0.34, and 3.11 mmol.g"-"1 for the starting TiO_2, the titanate-TiO_2 composite and the TEPA-titanate-TiO_2 composite (27.4 wt% of TEPA), respectively. The experimental isotherms of CO_2 were analysed using the Langmuir, Freundlich, Sips, Toth, Unilan, Redlich-Peterson, Radke-Prausnitz, Dubinin-Radushkevich, Temkin and Pyzhev, and Jovanovich models. The error sums of squares (SSR) function was used to test the fit of the models. The analysis revealed that the Sips isotherm is the best-fitting model for the CO_2 adsorption on the starting TiO_2, whereas the Freundlich equation should be used to describe the CO_2 adsorption isotherm on the titanate-TiO_2 composite. The CO_2 adsorption on the TEPA-modified sorbents was proposed to be described using the Sips isotherm for physical sorption and the modified Sips model for chemical sorption. The calculated isosteric heat of adsorption was found to be E46 kJ mol"-"1, which is about two times higher than the heat of CO_2 absorption in liquid TEPA reported in the literature (i.e. E85 kJ.mol"-"1). Therefore, it was concluded that the TEPA-titanate-TiO_2 composite is an attractive alternative for liquid amines due to the lower energy of regeneration in the sorption-desorption process. The material was proved to be stable during multiple sorption-desorption cycles. Moreover, its thermal stability up to 150 C was confirmed by thermogravimetric analysis (TGA). All these features make it a promising alternative for sorbents based on liquid amines. (authors)

  12. The safety designs for the TITAN reversed-field pinch reactor study

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Cheng, E.T.; Creedon, R.L.; Hoot, C.G.; Schultz, K.R.; Grotz, S.P.; Blanchard, J.; Sharafat, S.; Najmabadi, F.

    1989-01-01

    TITAN is a study to investigate the potential of the reversed-field pinch concept as a compact, high-power density energy system. Two reactor concepts were developed, a self-cooled lithium design with vanadium structure and an aqueous solution loop-in-pool design, both operating at 18 MW/m 2 . The key safety features of the TITAN-I lithium-vanadium blanket design are in material selection, fusion power core configuration selection, lithium piping connections, and passive lithium drain tank system. Based on these safety features and results from accident evaluation, TITAN-I can at least be rated at a level 3 of safety assurance. For the TITAN-II aqueous loop-in-pool design, the key passive feature is the complete submersion of the fusion power core and the corresponding primary coolant loop system into a pool of low temperature water. Based on this key safety design feature, the TITAN-II design can be rated at a level 2 of safety assurance. (orig.)

  13. The safety designs for the TITAN reversed-field pinch reactor study

    International Nuclear Information System (INIS)

    Wong, C.P.C.; Cheng, E.T.; Creedon, R.L.; Hoot, C.G.; Schultz, K.R.; Grotz, S.P.; Blanchard, J.P.; Sharafat, S.; Najmabadi, F.

    1988-01-01

    TITAN is a study to investigate the potential of the reversed-field pinch concept as a compact, high-power density energy system. Two reactor concepts were developed, a self-cooled lithium design with vanadium structure and an aqueous solution loop-in-pool design, both operating at 18 MW/m 2 . The key safety features of the TITAN-I lithium-vanadium blanket design are in material selection, fusion power core configuration selection, lithium piping connections and passive lithium drain tank system. Based on these safety features and results from accident evaluation, TITAN-I can at least be rated as level 3 of safety assurance. For the TITAN-II aqueous loop-in-pool design, the key passive feature is the complete submersion of the fusion power core and the corresponding primary coolant loop system into a pool of low temperature water. Based on this key safety design feature, the TITAN-II design can be rated as level 2 of safety assurance. 7 refs., 2 figs

  14. Tritium release from lithium titanate, a low-activation tritium breeding material

    International Nuclear Information System (INIS)

    Kopasz, J.P.; Miller, J.M.; Johnson, C.E.

    1994-01-01

    The goals for fusion power are to produce energy in as safe, economical, and environmentally benign a manner as possible. To ensure environmentally sound operation low-activation materials should be used where feasible. The ARIES Tokamak Reactor Study has based reactor designs on the concept of using low-activation materials throughout the fusion reactor. For the tritium breeding blanket, the choices for low activation tritium breeding materials are limited. Lithium titanate is an alternative low-activation ceramic material for use in the tritium breeding blanket. To date, very little work has been done on characterizing the tritium release for lithium titanate. We have thus performed laboratory studies of tritium release from irradiated lithium titanate. The results indicate that tritium is easily removed from lithium titanate at temperatures as low as 600 K. The method of titanate preparation was found to affect the tritium release, and the addition of 0.1% H 2 to the helium purge gas did not improve tritium recovery. ((orig.))

  15. Detection and mapping of organic molecules in Titan's atmosphere using ALMA

    Science.gov (United States)

    Cordiner, Martin

    2016-06-01

    Titan's atmospheric photochemistry results in the production of a wide range of organic molecules, including hydrocarbons, nitriles, aromatics and other complex species of possible pre-biotic relevance. Studies of Titan's atmospheric chemistry thus provide a unique opportunity to explore the origin and evolution of organic matter in primitive (terrestrial) planetary atmospheres. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new facility, well suited to the study of molecular emission from Titan's upper and middle-atmosphere. Results will be presented from our ongoing studies of Titan using ALMA data obtained during the period 2012-2014 [1,2], including detection and mapping of emission from C2H5CN, HNC, HC3N, CH3CN and CH3CCH. In addition, combining data from multiple ALMA Band 6 observations, we obtained high-resolution spectra with unprecedented sensitivity, enabling the first detection of C2H3CN (vinyl cyanide) on Titan, and derived a mean C2H3CN C2H5CN abundance ratio above 300 km of 0.3. Vinyl cyanide has recently been investigated as a possible constituent of (pre-biotic) vesicle membranes in Titan's liquid CH4 oceans [3]. Radiative transfer models and possible chemical formation pathways for the detected molecules will be discussed. ALMA observations provide instantaneous snapshot mapping of Titan's entire Earth-facing hemisphere for gases inaccessible to previous studies, and therefore provide new insights into photochemical production and transport, particularly at higher altitudes. Our maps show spatially resolved peaks in Titan's northern and southern hemispheres, consistent with the molecular distributions found in previous studies at infrared wavelengths by Voyager and Cassini, but high-altitude longitudinal asymmetries in our nitrile data indicate that the mesosphere may be more spatially variable than previously thought.

  16. The Influence of Runoff and Surface Hydrology on Titan's Weather and Climate

    Science.gov (United States)

    Faulk, S.; Lora, J. M.; Mitchell, J.; Moon, S.

    2017-12-01

    Titan's surface liquid distribution has been shown by general circulation models (GCMs) to greatly influence the hydrological cycle, producing characteristic weather and seasonal climate patterns. Simulations from the Titan Atmospheric Model (TAM) with imposed polar methane "wetlands" reservoirs realistically produce observed cloud features and temperature profiles of Titan's atmosphere, whereas "aquaplanet" simulations with a global methane ocean are not as successful. In addition, wetlands simulations, unlike aquaplanet simulations, demonstrate strong correlations between extreme rainfall behavior and observed geomorphic features, indicating the influential role of precipitation in shaping Titan's surface. The wetlands configuration is, in part, motivated by Titan's large-scale topography featuring low-latitude highlands and high-latitude lowlands, with the implication being that methane may concentrate in the high-latitude lowlands by way of runoff and subsurface flow of a global or regional methane table. However, the extent to which topography controls the surface liquid distribution and thus impacts the global hydrological cycle by driving surface and subsurface flow is unclear. Here we present TAM simulations wherein the imposed wetlands reservoirs are replaced by a surface runoff scheme that allows surface liquid to self-consistently redistribute under the influence of topography. We discuss the impact of surface runoff on the surface liquid distribution over seasonal timescales and compare the resulting hydrological cycle to observed cloud and surface features, as well as to the hydrological cycles of the TAM wetlands and aquaplanet simulations. While still idealized, this more realistic representation of Titan's hydrology provides new insight into the complex interaction between Titan's atmosphere and surface, demonstrates the influence of surface runoff on Titan's global climate, and lays the groundwork for further surface hydrology developments in Titan

  17. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Hoerst, S. M.; Tolbert, M. A, E-mail: sarah.horst@colorado.edu [Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO (United States)

    2013-06-10

    The organic haze produced from complex CH{sub 4}/N{sub 2} chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH{sub 4} concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  18. Infrared Spectra and Optical Constants of Nitrile Ices Relevant to Titan's Atmosphere

    Science.gov (United States)

    Anderson, Carrie; Ferrante, Robert F.; Moore, W. James; Hudson, Reggie; Moore, Marla H.

    2011-01-01

    Spectra and optical constants of nitrile ices known or suspected to be in Titan?s atmosphere have been determined from 2.0 to 333.3 microns (approx.5000 to 30/cm). These results are relevant to the ongoing modeling of Cassini CIRS observations of Titan?s winter pole. Ices studied were: HCN, hydrogen cyanide; C2N2, cyanogen; CH3CN, acetonitrile; C2H5CN, propionitrile; and HC3N, cyanoacetylene. Optical constants were calculated, using Kramers-Kronig analysis, for each nitrile ice?s spectrum measured at a variety of temperatures, in both the amorphous- and crystalline phases. Spectra were also measured for many of the nitriles after quenching at the annealing temperature and compared with those of annealed ices. For each of these molecules we also measured the real component, n, of the refractive index for amorphous and crystalline phases at 670 nm. Several examples of the information contained in these new data sets and their usefulness in modeling Titan?s observed features will be presented (e.g., the broad emission feature at 160/cm; Anderson and Samuelson, 2011).

  19. IN SITU MEASUREMENTS OF THE SIZE AND DENSITY OF TITAN AEROSOL ANALOGS

    International Nuclear Information System (INIS)

    Hörst, S. M.; Tolbert, M. A

    2013-01-01

    The organic haze produced from complex CH 4 /N 2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's surface and participate in both fluvial and aeolian processes. Models that seek to understand these processes require information about the physical properties of the particles including their size and density. Although measurements obtained by Cassini-Huygens have placed constraints on the size of the haze particles, their densities remain unknown. We have conducted a series of Titan atmosphere simulation experiments and measured the size, number density, and particle density of Titan aerosol analogs, or tholins, for CH 4 concentrations from 0.01% to 10% using two different energy sources, spark discharge and UV. We find that the densities currently in use by many Titan models are higher than the measured densities of our tholins.

  20. Study of the dielectric properties of barium titanate-polymer composites

    International Nuclear Information System (INIS)

    Pant, H.C.; Patra, M.K.; Verma, Aditya; Vadera, S.R.; Kumar, N.

    2006-01-01

    A comparative study of complex dielectric properties has been carried out at the X-band of microwave frequencies of composites of barium titanate (BaTiO 3 ) with two different polymer matrices: insulating polyaniline (PANI) powder (emeraldine base) and maleic resin. From these studies, it is observed that the composites of BaTiO 3 with maleic resin show normal composite behavior and the dielectric constant follows the asymmetric Bruggeman model. In contrast, the composites of BaTiO 3 with PANI show an unusual behavior wherein even at a low concentration of PANI (5 wt.%) there is a drastic reduction in the dielectric constant of BaTiO 3 . This behavior of the dielectric constant is explained on the basis of coating of BaTiO 3 particles by PANI which in turn is attributed to the highly surface adsorbing character. The materials have also been characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and optical microscopy studies

  1. Technological properties and structure of titanate melts

    International Nuclear Information System (INIS)

    Morozov, A.A.

    2002-01-01

    Power substantiation of existence of tough stream of complex anion ([TiO 6 ] 8- ) as a prevalent unit in titanate melts is given on the base of up-to-date knowledge about structure of metallurgical slags and results of investigations of thermophysical properties of these melts. It is shown that high crystallization ability of titanate melts at technological temperatures is determined by heterogeneity of liquid state - by presence up to 30 % of dispersed particles of solid phase solutions in matrix liquid [ru

  2. Observations of CO in Titan's Atmosphere Using ALMA

    Science.gov (United States)

    Serigano, Joseph; Nixon, Conor A.; Cordiner, Martin; Irwin, Patrick G. J.; Teanby, Nicholas; Charnley, Steven B.; Lindberg, Johan E.; Remijan, Anthony J.

    2015-11-01

    The advent of the Atacama Large Millimeter/submillimeter Array (ALMA) has provided a powerful facility for probing the atmospheres of solar system targets at long wavelengths (84-720 GHz) where the rotational lines of small, polar molecules are prominent. In the dense, nitrogen-dominated atmosphere of Titan, photodissociation of molecular nitrogen and methane leads to a wealth of complex hydrocarbons and nitriles in small abundances. Past millimeter/submillimeter observations, including ground-based observations as well as those by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft, have proven the significance of this wavelength region for the derivation of vertical mixing profiles, latitudinal and seasonal variations, and molecular detections. Previous ALMA studies of Titan have presented mapping and vertical column densities of hydrogen isocyanide (HNC) and cyanoacetylene (HC3N) (Cordiner et al. 2014) as well as the first spectroscopic detection of ethyl cyanide (C2H5CN) in Titan’s atmosphere (Cordiner et al. 2015).Here, we report several submillimetric observations of carbon monoxide (CO) and its isotopologues 13CO, C18O, and C17O in Titan’s atmosphere obtained with flux calibration data from the ALMA Science Archive. We employ NEMESIS, a line-by-line radiative transfer code, to determine the stratospheric abundances of these molecules. The abundance of CO in Titan's atmosphere is determined to be approximately 50±1 ppm, constant with altitude, and isotopic ratios are determined to be approximately 12C/13C = 90, 16O/18O = 470, and 16O/17O = 2800. This report presents the first spectroscopic detection of C17O in the outer solar system, detected at >11σ confidence. This talk will focus on isotopic ratios in CO in Titan's atmosphere and will compare our results to previously measured values for Titan and other bodies in the Solar System. General implications for the history of Titan from measurements of CO and its isotopologues will be

  3. Titan's Primordial Soup: Formation of Amino Acids via Low Temperature Hydrolysis of Tholins

    Science.gov (United States)

    Neish, Catherine; Somogyi, Á.; Smith, M. A.

    2009-09-01

    Titan, Saturn's largest moon, is a world rich in the "stuff of life". Reactions occurring in its dense nitrogen-methane atmosphere produce a wide variety of organic molecules, which subsequently rain down onto its surface. Water - thought to be another important ingredient for life - is likewise abundant on Titan. Theoretical models of Titan's formation predict that its interior consists of an ice I layer several tens of kilometers thick overlying a liquid ammonia-rich water layer several hundred kilometers thick (Tobie et al., 2005). Though its surface temperature of 94K dictates that Titan is on average too cold for liquid water to persist at its surface, melting caused by impacts and/or cryovolcanism may lead to its episodic availability. Impact melt pools on Titan would likely remain liquid for 102 - 104 years before freezing (O'Brien et al., 2005). The combination of complex organic molecules and transient locales of liquid water make Titan an interesting natural laboratory for studying prebiotic chemistry. In this work, we sought to determine what biomolecules might be formed under conditions analogous to those found in transient liquid water environments on Titan. We hydrolyzed Titan organic haze analogues, or "tholins", in 13 wt. % ammonia-water at 253K and 293K for a year. Using a combination of high resolution mass spectroscopy and tandem mass spectroscopy fragmentation techniques, four amino acids were identified in the hydrolyzed tholin sample. These four species have been assigned as the amino acids asparagine, aspartic acid, glutamine, and glutamic acid. This represents the first detection of biologically relevant molecules created under conditions similar to those found in impact melt pools and cryolavas on Titan. Future missions to Titan should therefore carry instrumentation capable of detecting amino acids and other prebiotically relevant molecules on its surface This work was supported by the NASA Exobiology Program.

  4. MICROSTRUCTURE CHARACTERISTIC OF ALUMINUM TITANATE SYNTHESIED BY BOTH SOLID- STATE AND SOL-GEL PROCESSES

    Directory of Open Access Journals (Sweden)

    M. Khosravi Saghezchi

    2015-12-01

    Full Text Available A comparing study on formation and microstructure features of aluminum titanate is investigated through both solid-state and sol-gel processes. Aluminum titanate formed by firing at 1350ºC and 1450ºC for 4h in solid-state process. In the sol-gel process formation of submicron sized particles is followed by addition of sucrose into the transparent sol. XRD analysis was confirmed the formation of aluminum titanate at 1400ºC  in lower duration of calcination (3h without any additives in the sol-gel process. In this work 2wt% MgO is added to the samples as the additive for forming acceleration of aluminum titanate. The influence of MgO addition and heat treatment are studied on phase formation and microstructure development of aluminum titanate in both procedures. Additive optimizes aluminum titanate formation at lower temperatures (1300-1350ºC. Phase and microstructure studies of Mg containing samples optimally show significance in aluminum titanate formation.

  5. Large catchment area recharges Titan's Ontario Lacus

    Science.gov (United States)

    Dhingra, Rajani D.; Barnes, Jason W.; Yanites, Brian J.; Kirk, Randolph L.

    2018-01-01

    We seek to address the question of what processes are at work to fill Ontario Lacus while other, deeper south polar basins remain empty. Our hydrological analysis indicates that Ontario Lacus has a catchment area spanning 5.5% of Titan's surface and a large catchment area to lake surface area ratio. This large catchment area translates into large volumes of liquid making their way to Ontario Lacus after rainfall. The areal extent of the catchment extends to at least southern mid-latitudes (40°S). Mass conservation calculations indicate that runoff alone might completely fill Ontario Lacus within less than half a Titan year (1 Titan year = 29.5 Earth years) assuming no infiltration. Cassini Visual and Infrared Mapping Spectrometer (VIMS) observations of clouds over the southern mid and high-latitudes are consistent with precipitation feeding Ontario's large catchment area. This far-flung rain may be keeping Ontario Lacus filled, making it a liquid hydrocarbon oasis in the relatively dry south polar region.

  6. Light scattering measurements with Titan's aerosols analogues produced by dusty plasma

    Science.gov (United States)

    Hadamcik, E.; Renard, J.-B.; Szopa, C.; Cernogora, G.; Levasseur-Regourd, A. C.

    The Titan s atmosphere contains solid aerosols produced by the photochemistry of nitrogen and methane These aerosols are at the origin of the characteristic brown yellow colour of Titan During the descent of the Huygens probe the 14 th January 2005 optical measurements of the Titan s haze and Titan s surface have been done In order to explain the obtained results laboratory simulations are necessary We produce analogues of the Titan s aerosols in a RF capacitively coupled low-pressure plasma in a N 2 --CH 4 mixture representative of the Titan s atmosphere Szopa et al 2006 Szopa et al this conference The morphology of the produced solid aerosols is observed by SEM analyses They are quasi spherical and their mean size is function of the plasma conditions Moreover their colour changes from yellow to brown as a function of CH 4 ratio in the plasma In order to have information on the optical properties of the produced aerosols measurements have been performed with the PROGRA2 experiment Renard et al 2002 The PROGRA2 experiment measures the phase dependence of the linear polarization of the light scattered by dust particles for two wavelengths 543 5 nm and 632 8 nm The particles are lifted either in microgravity in the CNES ESA dedicated airplane or by an air-draught in ground-based conditions The aim of this work is to build a database for further modelling of the optical properties of Titan s in connection with the Huygens data These particles have also an astrophysical interest as organic compounds Hadamcik et

  7. Fiscal 1999 research result report. Research on improvement of boiling heat transfer characteristics by photocatalyst wall; 1999 nendo hikari shokubai hekimen ni yoru futto netsu dentatsu tokusei kaizen ni kansuru kenkyu chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Research was made on improvement of the wettability and boiling heat transfer characteristics of a photocatalyst wall. Measurement experiment of the wettability was made for anatase type titan oxide-coated Al, SUS and Pb plates, rutil type titan oxide-flame coated SUS plate, raw plate, and oxide-plasma coated titan plate. In the ground experiment, the contact angles of distilled water and oil on specimen surfaces were measured. In the microgravity experiment, falling droplet images were recorded by using the facility of Japan Microgravity Center (JAMIC). For obtaining the effect of radioactive emission, UV irradiation, {gamma} ray and neutron beam irradiation by nuclear reactor, and {gamma} ray irradiation by Co-60 were carried out. As the experiment result, the rutil type titan oxide-flame coated SUS plate, nonconductor-coated titan plate, and zircaloy plate showed large improvement of the wettability by {gamma} ray irradiation with Co-60. It was also confirmed that in particular, titan shows the large effect of radioactive emission, and the wettability deteriorates rapidly after {gamma} ray irradiation. (NEDO)

  8. Study of the growth of CeO2 nanoparticles onto titanate nanotubes

    Science.gov (United States)

    Marques, Thalles M. F.; Ferreira, Odair P.; da Costa, Jose A. P.; Fujisawa, Kazunori; Terrones, Mauricio; Viana, Bartolomeu C.

    2015-12-01

    We report the study of the growth of CeO2 nanoparticles on the external walls and Ce4+ intercalation within the titanate nanotubes. The materials were fully characterized by multiple techniques, such as: Raman spectroscopy, infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The ion exchange processes in the titanate nanotubes were carried out using different concentrations of Ce4+ in aqueous solution. Our results indicate that the growth of CeO2 nanoparticles grown mediated by the hydrolysis in the colloidal species of Ce and the attachment onto the titanate nanotubes happened and get it strongly anchored to the titanate nanotube surface by a simple electrostatic interaction between the nanoparticles and titanate nanotubes, which can explain the small size and even distribution of nanoparticles on titanate supports. It was demonstrated that it is possible to control the amount and size of CeO2 nanoparticles onto the nanotube surface, the species of the Ce ions intercalated between the layers of titanate nanotubes, and the materials could be tuned for using in specific catalysis in according with the amount of CeO2 nanoparticles, their oxygen vacancies/defects and the types of Ce species (Ce4+ or Ce3+) present into the nanotubes.

  9. Thermal stability of titanate nanorods and titania nanowires formed from titanate nanotubes by heating

    Czech Academy of Sciences Publication Activity Database

    Brunátová, T.; Matěj, Z.; Oleynikov, P.; Vesely, J.; Danis, S.; Popelková, Daniela; Kuzel, R.

    2014-01-01

    Roč. 98, December (2014), s. 26-36 ISSN 1044-5803 Institutional support: RVO:61389013 Keywords : titania nanowires * titanate nanorods * X-ray diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.845, year: 2014

  10. Coexistence of Dunes and Humid Conditions at Titan's Tropics

    Science.gov (United States)

    Radebaugh, Jani; Lorenz, R. D.; Lunine, J. I.; Kirk, R. L.; Ori, G. G.; Farr, T. G.; Malaska, M.; Le Gall, A.; Liu, Z. Y. C.; Encrenaz, P. J.; Paillou, P.; Hayes, A.; Lopes, R. M. C.; Turtle, E. P.; Wall, S. D.; Stofan, E. R.; Wood, C. A.; Cassini RADAR Team

    2012-10-01

    At Titan's equatorial latitudes there are tens of thousands of dunes, a landform typical of desert environments where sand does not become anchored by vegetation or fluids. Model climate simulations predict generally dry conditions at the equator and humid conditions near the poles of Titan, where lakes of methane/ethane are found. However, moderate relative methane humidity was observed at the Huygens landing site, recent rainfall was seen by Cassini ISS near the Belet Sand Sea, and a putative transient lake in Shangri-La was observed by Cassini VIMS, all of which indicate abundant fluids may be present, at least periodically, at Titan's equatorial latitudes. Terrestrial observations and studies demonstrate dunes can exist and migrate in conditions of high humidity. Active dunes are found in humid climates, indicating the movement of sand is not always prohibited by the presence of fluids. Sand mobility is related to precipitation, evaporation and wind speed and direction. If dune surfaces become wetted by rainfall or rising subsurface fluids, they can become immobilized. However, winds can act to dry the uppermost layers, freeing sands for saltation and enabling dune migration in wet conditions. Active dunes are found in tropical NE Brazil and NE Australia, where there are alternating dry and wet periods, a condition possible for Titan's tropics. Rising and falling water levels lead to the alteration of dune forms, mainly from being anchored by vegetation, but also from cementation by carbonates or clays. Studies of Titan's dunes, which could undergo anchoring of organic sediments by hydrocarbon fluids, could inform the relative strength of vegetation vs. cementation at humid dune regions on Earth. Furthermore, a comprehensive survey of dune morphologies near regions deemed low by SARTopo and stereo, where liquids may collect in wet conditions, could reveal if bodies of liquid have recently existed at Titan's tropics.

  11. Crystal structure of red lead titanate thin films

    International Nuclear Information System (INIS)

    Bursill, L.A.; Peng, J.L.; Jiang, B.; Li, X.

    1998-01-01

    Orange-red lead titanate thin films are examined by high-resolution transmission electron microscopy and diffraction. It is remarkable that the structure is based on that of tetragonal-tungsten-bronze (TTB) rather than perovskite-type. The chemical basis for this result is examined. It is deduced that the TTB structure is stabilized by inclusion of hydroxyl ions during synthesis by a sol-gel route involving hydrolysis of n-Butyl titanate

  12. Predicting Passenger Survival Rates on the Titanic

    OpenAIRE

    Prateek Chanda

    2017-01-01

    The sinking of the RMS Titanic is one of the most infamous shipwrecks in history. On April 15, 1912, during her maiden voyage, the Titanic sank after colliding with an iceberg, killing 1502 out of 2224 passengers and crew. This sensational tragedy shocked the international community and led to better safety regulations for ships. One of the reasons that the shipwreck led to such loss of life was that there were not enough lifeboats for the passengers and crew. Although there was some el...

  13. Behavior under Extreme Conditions: The Titanic Disaster

    OpenAIRE

    Bruno S. Frey; David A. Savage; Benno Torgler

    2011-01-01

    During the night of April 14, 1912, the RMS Titanic collided with an iceberg on her maiden voyage. Two hours and 40 minutes later she sank, resulting in the loss of 1,501 lives—more than two-thirds of her 2,207 passengers and crew. This remains one of the deadliest peacetime maritime disasters in history and by far the most famous. For social scientists, evidence about how people behaved as the Titanic sunk offers a quasi-natural field experiment to explore behavior under extreme conditions o...

  14. Spectroscopy of carbonated chains: experimental investigation and observation of Titan's atmosphere

    International Nuclear Information System (INIS)

    Jolly, Antoine

    2012-01-01

    In this report for an Accreditation to Supervise Research (HDR), the author proposes an overview of his research works. These works first addressed quantitative spectroscopy and more particularly the measurement of absolute absorption coefficients which are necessary parameters for the quantification of molecules which are remotely sensed through their spectroscopic signature. Secondly, the author addresses the adjustment of line lists in the infrared for a better investigation of recent observations of Titan's atmosphere made by the Cassini mission. Thirdly, he reports the use of this line list for the processing of observations of Titan. The last part addresses an experimental atmospheric simulation which aims at reproducing Titan's atmosphere by submitting its main components (nitrogen and methane) to an energetic flow representative of what is present on Titan

  15. Low temperature fabrication of barium titanate hybrid films and their dielectric properties

    International Nuclear Information System (INIS)

    Kobayashi, Yoshio; Saito, Hirobumi; Kinoshita, Takafumi; Nagao, Daisuke; Konno, Mikio

    2011-01-01

    A method for incorporating BT nano-crystalline into barium titanate (BT) films is proposed for a low temperature fabrication of high dielectric constant films. BT nanoparticles were synthesized by hydrolysis of a BT complex alkoxide in 2-methoxyethanol (ME)/ethanol cosolvent. As the ME volume fraction in the cosolvent (ME fraction) increased from 0 to 100%, the particle and crystal sizes tended to increase from 13.4 to 30.2 nm and from 15.8 to 31.4 nm, respectively, and the particle dispersion in the solution became more improved. The BT particles were mixed with BT complex alkoxide dissolved in an ME/ethanol cosolvent for preparing a precursor solution that was then spin-coated on a Pt substrate and dried at 150 o C. The dielectric constant of the spin-coated BT hybrid film increased with an increase in the volume fraction of the BT particles in the film. The dissipation factor of the hybrid film tended to decrease with an increase in the ME fraction in the precursor solution. The hybrid film fabricated at a BT fraction of 30% and an ME fraction of 25% attained a dielectric constant as high as 94.5 with a surface roughness of 14.0 nm and a dissipation factor of 0.11.

  16. TiO2/silane coupling agent composed of two layers structure: A super-hydrophilic self-cleaning coating applied in PV panels

    International Nuclear Information System (INIS)

    Zhong, Hong; Hu, Yan; Wang, Yuanhao; Yang, Hongxing

    2017-01-01

    Highlights: •A self-coating with composited layer structure can applied in PV panels is proposed. •This coating is consisted of TiO 2 and KH550. •pH in hydrothermal reaction is an important factor to control the self-cleaning property and light transmittance of coating. •This coating can increase the output of PV panels in outside test. -- Abstract: To improve the properties of anti-dust for PV modules, the concept of self-cleaning has been proposed for many years. However, the traditional self-cleaning coating is unstable in nature environment, which limited its application in the PV panels. Therefore, this study aims to design a novel super-hydrophilic coating with high stability and corrosion resistance, which would be very advantageous to apply in the PV panels. The super-hydrophilic self-cleaning coating is composed of 3-triethoxysilylpropylamine (KH550) and TiO 2 . KH550 is a kind of surface modification agent, which creates more active groups on the surface of glasses. TiO 2 is prepared by a hydrothermal reaction with titanium ethoxide, and the influence of pH is investigated as an important factor during the application in PV panels. The composition was measured by UV/VIS/NIR spectrophotometer, and the particle size distribution and the surface structure were characterized by Scanning Electron Microscope (SEM). The TiO 2 nanocrystal was investigated by X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM). The water contact angle (WCA) was measured by contact angle instrument. It was found that the static water contact angle on the surface of super-hydrophobic coating was as lower than 5°, which show an excellent super-hydrophilic property. Abstract should state the principal results and conclusions briefly, and the significance of this study.

  17. Calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray and post-deposition thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ctibor, Pavel [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Kotlan, Jiri, E-mail: kotlan@ipp.cas.cz [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6 (Czech Republic); Pala, Zdenek [Materials Engineering Department, Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, Prague 8 (Czech Republic); Sedlacek, Josef [Department of Electrotechnology, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6 (Czech Republic); Hajkova, Zuzana; Grygar, Tomas Matys [Institute of Inorganic Chemistry ASCR, v.v.i., Husinec-Rez 1001, Rez (Czech Republic)

    2015-12-15

    Highlights: • Calcium titanate was sprayed by two different plasma spray systems. • Significant improvement of dielectric properties after annealing was observed. • Calcium titanate self-supporting parts can be fabricated by plasma spraying. - Abstract: This paper studies calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray technology. A water stabilized plasma gun (WSP) as well as a widely used gas stabilized plasma gun (GSP) were employed in this study to deposit three sample sets at different spray conditions. Prepared specimens were annealed in air at atmospheric pressure for 2 h at various temperatures from 530 to 1170 °C. X-ray diffraction (XRD), Raman spectroscopy and porosity measurements were used for sample characterization. Dielectric spectroscopy was applied to obtain relative permittivity, conductivity and loss factor frequency dependence. Band gap energy was estimated from reflectance measurements. The work is focused on the explanation of changes in microstructure and properties of a plasma sprayed deposit after thermal annealing. Obtained results show significant improvement of dielectric properties after thermal annealing.

  18. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  19. Ethane ocean on Titan

    Science.gov (United States)

    Lunine, J. I.; Stevenson, D. J.; Yung, Y.L.

    1983-01-01

    Voyager I radio occultation data is employed to develop a qualitative model of an ethane ocean on Titan. It is suggested that the ocean contains 25 percent CH4 and that the ocean is in dynamic equilibrium with an N2 atmosphere. Previous models of a CH4 ocean are discounted due to photolysis rates of CH4 gas. Tidal damping of Titan's orbital eccentricity is taken as evidence for an ocean layer approximately 1 km deep, with the ocean floor being covered with a solid C2H2 layer 100 to 200 m thick. The photolytic process disrupting the CH4, if the estimates of the oceanic content of CH4 are correct, could continue for at least one billion years. Verification of the model is dependent on detecting CH4 clouds in the lower atmosphere, finding C2H6 saturation in the lower troposphere, or obtaining evidence of a global ocean.

  20. Organic chemistry on Titan

    Science.gov (United States)

    Chang, S.; Scattergood, T.; Aronowitz, S.; Flores, J.

    1979-01-01

    Features taken from various models of Titan's atmosphere are combined in a working composite model that provides environmental constraints within which different pathways for organic chemical synthesis are determined. Experimental results and theoretical modeling suggest that the organic chemistry of the satellite is dominated by two processes: photochemistry and energetic particle bombardment. Photochemical reactions of CH4 in the upper atmosphere can account for the presence of C2 hydrocarbons. Reactions initiated at various levels of the atmosphere by cosmic rays, Saturn 'wind', and solar wind particle bombardment of a CH4-N2 atmospheric mixture can account for the UV-visible absorbing stratospheric haze, the reddish appearance of the satellite, and some of the C2 hydrocarbons. In the lower atmosphere photochemical processes will be important if surface temperatures are sufficiently high for gaseous NH3 to exist. It is concluded that the surface of Titan may contain ancient or recent organic matter (or both) produced in the atmosphere.

  1. Effect of cerium (IV) ions on the anticorrosion properties of siloxane-poly(methyl methacrylate) based film applied on tin coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Suegama, P.H. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, CP 61548, 05424-970 Sao Paulo, SP (Brazil); Sarmento, V.H.V. [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil); Montemor, M.F. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Benedetti, A.V. [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil); de Melo, H.G.; Aoki, I.V. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, CP 61548, 05424-970 Sao Paulo, SP (Brazil); Santilli, C.V., E-mail: santilli@iq.unesp.b [Departamento Fisico-Quimica, Instituto de Quimica, Universidade Estadual Paulista, UNESP, CP 355, 14801-970 Araraquara, SP (Brazil)

    2010-07-15

    This work investigates the influence of the addition of cerium (IV) ions on the anticorrosion properties of organic-inorganic hybrid coatings applied to passivated tin coated steel. In order to evaluate the specific effect of cerium (IV) addition on nanostructural features of the organic and inorganic phases of the hybrid coating, the hydrolytic polycondensation of silicon alkoxide and the radical polymerization of the methyl methacrylate (MMA) function were induced separately. The corrosion resistance of the coatings was evaluated by means of linear polarization, Tafel type curves and electrochemical impedance measurements. The impedance results obtained for the hybrid coatings were discussed based on an electrical equivalent circuit used to fit the experimental data. The electrochemical results clearly showed the improvement of the protective properties of the organic-inorganic hybrid coating mainly when the cerium (IV) was added to the organic phase solution precursor, which seemed to be due to the formation of a more uniform and densely reticulated siloxane-PMMA film.

  2. Effect of cerium (IV) ions on the anticorrosion properties of siloxane-poly(methyl methacrylate) based film applied on tin coated steel

    International Nuclear Information System (INIS)

    Suegama, P.H.; Sarmento, V.H.V.; Montemor, M.F.; Benedetti, A.V.; de Melo, H.G.; Aoki, I.V.; Santilli, C.V.

    2010-01-01

    This work investigates the influence of the addition of cerium (IV) ions on the anticorrosion properties of organic-inorganic hybrid coatings applied to passivated tin coated steel. In order to evaluate the specific effect of cerium (IV) addition on nanostructural features of the organic and inorganic phases of the hybrid coating, the hydrolytic polycondensation of silicon alkoxide and the radical polymerization of the methyl methacrylate (MMA) function were induced separately. The corrosion resistance of the coatings was evaluated by means of linear polarization, Tafel type curves and electrochemical impedance measurements. The impedance results obtained for the hybrid coatings were discussed based on an electrical equivalent circuit used to fit the experimental data. The electrochemical results clearly showed the improvement of the protective properties of the organic-inorganic hybrid coating mainly when the cerium (IV) was added to the organic phase solution precursor, which seemed to be due to the formation of a more uniform and densely reticulated siloxane-PMMA film.

  3. Equinoctial Activity Over Titan Dune Fields Revealed by Cassini/vims

    Science.gov (United States)

    Rodriguez, S.; Le Mouelic, S.; Barnes, J. W.; Hirtzig, M.; Rannou, P.; Sotin, C.; Brown, R. H.; Bow, J.; Vixie, G.; Cornet, T.; Bourgeois, O.; Narteau, C.; Courrech Du Pont, S.; Le Gall, A.; Reffet, E.; Griffith, C. A.; Jaumann, R.; Stephan, K.; Buratti, B. J.; Clark, R. N.; Baines, K. H.; Nicholson, P. D.; Coustenis, A.

    2012-12-01

    Titan, the largest satellite of Saturn, is the only satellite in the solar system with a dense atmosphere. The close and continuous observations of Titan by the Cassini spacecraft, in orbit around Saturn since July 2004, bring us evidences that Titan troposphere and low stratosphere experience an exotic, but complete meteorological cycle similar to the Earth hydrological cycle, with hydrocarbons evaporation, condensation in clouds, and rainfall. Cassini monitoring campaigns also demonstrate that Titan's cloud coverage and climate vary with latitude. Titan's tropics, with globally weak meteorological activity and widespread dune fields, seem to be slightly more arid than the poles, where extensive and numerous liquid reservoirs and sustained cloud activity have been discovered. Only a few tropo-spheric clouds have been observed at Titan's tropics during the southern summer. As equinox was approaching (in August 2009), they occurred more frequently and appeared to grow in strength and size. We present here the observation of intense brightening at Titan's tropics, very close to the equinox. These detections were conducted with the Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini. We will discuss the VIMS images of the three individual events detected so far, observed during the Titan's flybys T56 (22 May 2009), T65 (13 January 2010) and T70 (21 June 2010). T56, T65 and T70 observations show an intense and transient brighten-ing of large regions very close to the equator, right over the extensive dune fields of Senkyo, Belet and Shangri-La. They all appear spectrally and morphologically different from all transient surface features or atmospheric phenomena previously reported. Indeed, these events share in particular a strong brightening at wavelengths greater than 2 μm (especially at 5 μm), making them spectrally distinct from the small tropical clouds observed before the equinox and the large storms observed near the equator in September and October

  4. What Does Titan's Atmosphere Look Like Near The Poles At The End Of The Cassini Mission ?

    Science.gov (United States)

    Nixon, C. A.; Coustenis, A.; Jennings, D. E.; Achterberg, R. K.; Bampasidis, G.; Cottini, V.; Flasar, F. M.; Lavvas, P.

    2017-12-01

    The Cassini mission ends on Sept. 15, 2017, after - among other - 127 targeted Titan flybys. We have monitored the seasonal evolution near Titan's poles during the mission. Titan's North pole had been enhanced in chemical species since the beginning of the observations, but since 2010, we observe at Titan's south pole a strong temperature decrease and the onset of a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously observed only at high northern latitudes (Coustenis et al. 2016 and references therein). This is due to the transition of Titan's seasons from northern winter in 2002 to northern summer in 2017 and, at the same time, the advent of winter in the south pole, during which time species with longer chemical lifetimes remain in the north for a little longer undergoing slow photochemical destruction, while those with shorter lifetimes disappear, reappearing in the south. An opposite effect has been expected in the North, but not observed with any significant certainty until 2016. We present here an analysis of nadir spectra acquired by Cassini/CIRS (Jennings et al., 2017) at high resolution in the past years and describe the newly observed decrease in chemical abundances of the components in the North. From 2013 until 2016, the Northern polar region has shown a temperature increase of 10 K, while the South had shown a more significant decrease in a similar period of time. The chemical content in the North is finally showing a clear depletion for most molecules since 2015 (Coustenis et al., 2017). References: Coustenis et al., 2016, Icarus 270, 409-420 ; Coustenis et al., 2017, submitted; Jennings et al., 2017, Applied Optics 56, no 18, 5274-5294.

  5. Descent imager/spectral radiometer (DISR) instrument aboard the Huygens probe of Titan

    Science.gov (United States)

    Tomasko, Martin G.; Doose, Lyn R.; Smith, Peter H.; Fellows, C.; Rizk, B.; See, C.; Bushroe, M.; McFarlane, E.; Wegryn, E.; Frans, E.; Clark, R.; Prout, M.; Clapp, S.

    1996-10-01

    The Huygen's probe of the atmosphere of Saturn's moon Titan includes one optical instrument sensitive to the wavelengths of solar radiation. The goals of this investigation fall into four broad areas: 1) the measurement of the profile of solar heating to support an improved understanding of the thermal balance of Titan and the role of the greenhouse effect in maintaining Titan's temperature structure; 2) the measurement of the size, vertical distribution, and optical properties of the aerosol and cloud particles in Titan's atmosphere to support studies of the origin, chemistry, life cycles, and role in the radiation balance of Titan played by these particles; 3) the composition of the atmosphere, particularly the vertical profile of the mixing ratio of methane, a condensable constituent in Titan's atmosphere; and 4) the physical state, composition, topography, and physical processes at work in determining the nature of the surface of Titan and its interaction with Titan's atmosphere. In order to accomplish these objectives, the Descent Imager/Spectral Radiometer (DISR) instrument makes extensive use of fiber optics to bring the light from several different sets of foreoptics to a silicon CCD detector, to a pair of InGaAs linear array detectors, and to three silicon photometers. Together these detectors permit DISR to make panoramic images of the clouds and surface of Titan, to measure the spectrum of upward and downward streaming sunlight from 350 to 1700 nm at a resolving power of about 200, to measure the reflection spectrum of >= 3000 locations on the surface, to measure the brightness and polarization of the solar aureole between 4 and 30 degrees from the sun at 500 and 935 nm, to separate the direct and diffuse downward solar flux at each wavelength measured, and to measure the continuous reflection spectrum of the ground between 850 and 1600 nm using an onboard lamp in the last 100 m of the descent.

  6. Formation of hydroxyapatite on Ti-coated Ti-Zr-Cu-Pd bulk metallic glass

    International Nuclear Information System (INIS)

    Qin, F.X.; Wang, X.M.; Wada, T.; Xie, G.Q.; Asami, K.; Inoue, A.

    2009-01-01

    In this research, Ti coating was conducted on Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glass (BMG) in order to increase the formation rate of hydroxyapatite layer. The formation behavior of bone-like hydroxyapatite on Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glasses (BMGs) was studied. The surface morphology of Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results revealed that the alkali pretreatment in 5 M NaOH solution at 60degC for 24 h had a beneficial effect on the formation of porous sodium titanate on Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG. A bone-like hydroxyapatite layer was able to form on the alkali-treated Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG after a short-time immersion in simulated body fluid (SBF). On the contrary, hydroxyapatite formation was not observed on the uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG after the same chemical treatments. (author)

  7. Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter

    Science.gov (United States)

    Sagan, Carl; Khare, B. N.; Thompson, W. R.; Mcdonald, G. D.; Wing, Michael R.; Bada, Jeffrey L.; Vo-Dinh, Tuan; Arakawa, E. T.

    1993-01-01

    PAHs are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites, are identified, with a net abundance of about 0.0001 g/g (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins.

  8. The key to Mars, Titan and beyond?

    International Nuclear Information System (INIS)

    Zubrin, R.M.

    1990-01-01

    This paper discusses the use of nuclear rockets using indigenous Mars propellants for future missions to Mars and Titan, which would drastically reduce the mass and cost of the mission while increasing its capability. Special attention is given to the CO2-powered nuclear rocket using indigenous Martian fuel (NIMF) vehicle for hopping around on Mars. If water is available on Mars, it could make a NIMF propellant yielding an exhaust velocity of 3.4 km/sec, good enough to allow a piloted NIMF spacecraft to ascent from the surface of Mars and propel itself directly to LEO; if water is available on Phobos, a NIMF spacecraft could travel to earth orbit and then back to Phobos or Mars without any additional propellant from earth. One of the many exciting missions beyond Mars that will be made possible by NIMF technology is the exploration of Saturn's moon Titan. A small automated NIMF Titan explorer, with foldout wings and a NERVA (Nuclear Engine for Rocket Vehicle Applications) engine, is proposed

  9. Modified titanate perovskites in photocatalytic water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Wlodarczak, M.; Ludwiczak, M.; Laniecki, M. [A. Mickiewicz Univ. (Poland)

    2010-07-01

    Received materials have structure of perovskite, what was shown by XRD diffraction patterns. Perovskite structure is present in all samples with strontium, barium and one sample with calcium. Moreover, received barium and strontium titanate are very similar to pattern materials. XRD results show, that temperature 500 C is too low to create perovskite structure in CaTiO{sub 3}. However, it is high enough in case of SrTiO{sub 3} and BaTiO{sub 3}. One regularity is obvious, surface area increases for samples calcined in lower temperature. There is a connection between surface area and dispersion of platinum. Both of them reach the greatest value to the calcium titanate. Catalytic activity was shown by all of received samples. Measurable values were received to samples calcined in 700 C. Calcium titanate had the best catalytic activity, both an amount of hydrogen and a ratio of hydrogen to platinum. There is one regularity to all samples, the ration of hydrogen to platinum increase when amount of platinum decrease. (orig.)

  10. Silver decorated titanate/titania nanostructures for efficient solar driven photocatalysis

    International Nuclear Information System (INIS)

    Gong, Dangguo; Ho, Weng Chye Jeffrey; Tang Yuxin; Tay Qiuling; Lai Yuekun; Highfield, James George; Chen Zhong

    2012-01-01

    Photocatalysis has attracted significant interest to solve both the energy crisis and effectively combat environmental contamination. However, as the most widely used photocatalyst, titania (TiO 2 ) suffers from inefficient utilization of solar energy due to its wide band gap. In the present paper, we describe a method to extend the absorption edge of photocatalyst to visible region by the surface plasmon effect of silver. Silver ions are photo-reduced onto the surface of titanate nanotubes, which are synthesized by a conventional hydrothermal method. The as-synthesized Ag/titanate composite is transformed into Ag/titania nanoparticles by annealing at different temperatures. It is found that the interaction of Ag nanoparticles with the supports (titanate/titania) plays a key role for the visible light activity. The samples annealed at low temperature (<350 °C) do not show significant activity under our conditions, while the one annealed at 450 °C shows fast-degradation of methyl orange (MO) under visible light irradiation. The detailed mechanisms are also discussed. - Graphical abstract: Silver nanoparticles decorated titanate/titania as visible light active photocatalysts: silver nanoparticles could be excited by visible light due to its surface plasmon effect and excited electrons could be transferred to the conduction band of the semiconductor, where the reduction process occurs. Highlights: ► Uniform Ag nanoparticles are photo-reduced onto titanate and titania nanostructures. ► Titania crystal is formed by annealing hydrogen titanate at different temperatures. ► Best visible-light activity is achieved by Ag-loaded titania annealed at 450 °C. ► The visible light activity is attributed to the surface plasmonic resonance effect.

  11. Crystal structure of red lead titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bursill, L.A.; Peng, J.L.; Jiang, B. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Li, X. [Jilin Univ., Changchun, JL (China). Dept of Chemistry

    1998-09-01

    Orange-red lead titanate thin films are examined by high-resolution transmission electron microscopy and diffraction. It is remarkable that the structure is based on that of tetragonal-tungsten-bronze (TTB) rather than perovskite-type. The chemical basis for this result is examined. It is deduced that the TTB structure is stabilized by inclusion of hydroxyl ions during synthesis by a sol-gel route involving hydrolysis of n-Butyl titanate 7 refs., 1 tab., 4 figs.

  12. Titan's interior from its rotation axis orientation and its Love number

    Science.gov (United States)

    Baland, Rose-Marie; Gabriel, Tobie; Axel, Lefèvre

    2013-04-01

    The tidal Love number k2 of Titan has been recently estimated from Cassini flybys radio-tracking and is consistent with the presence of a global ocean in Titan's interior, located between two ice layers (Iess et al. 2012), in accordance with prediction from interior and evolutionary models for Titan. Previously, the orientation of the rotation axis of Titan has been measured on the basis of radar images from Cassini (Stiles et al. 2008). Titan's obliquity, is about 0.3. The measured orientation is more consistent with the presence of a global internal liquid ocean than with an entirely solid Titan (Baland et al. 2011). The global topography data of Titan seem to indicate some departure from the hydrostatic shape expected for a synchronous satellite under the influence of its rotation and the static tides raised by the central planet (Zebker et al. 2009). This may be explained by a differential tidal heating in the ice shell which flattens the poles (Nimmo and Bills 2010). A surface more flattened than expected implies compensation in depth to explain the measured gravity coefficients C20 and C22 of Iess et al. (2012). Here, all layers are assumed to have a tri-axial ellipsoid shape, but with polar and equatorial flattenings that differ from the hydrostatic expected ones. We assess the influence of this non-hydrostatic shape on the conclusions of Baland et al. (2011), which developped a Cassini state model for the orientation of the rotation axis of a synchronous satellite having an internal liquid layer. We assess the possibility to constrain Titan's interior (and particularly the structure of the water/ice layer) from both the rotation axis orientation and the Love number. We consider a range of internal structure models consistent with the mean density and the mean radius of Titan, and made of a shell, an ocean, a mantle, and a core, from the surface to the center, with various possible compositions (e.g. ammonia mixed with water for the ocean). The internal

  13. Improvement of conditions for ceramics sintering on the base of lead zirconate-titanate

    International Nuclear Information System (INIS)

    Glinchuk, M.D.; Kim, P.V.; Bykov, I.P.; Lyashchenko, A.B.

    1989-01-01

    Lead zirconate-titanate powders of different graininess are studied for their phase composition. The finest grains of the powder consist of lead zirconate-titanate with the rhombohedral structure. Grains of 3-5 μm size are a mixture of lead zirconate-titanate and lead titanate, the latter exceeding 50% (by weight) causes the effect of anomalous expansion in the process of sintering. Control of the technological parameters of the synthesis permits producing powder with favourable correlation of the above phases and grain sizes. Sintering of such a powder induces no effect of the anomalous expansion with an increased density of the product attained

  14. Anion and cation diffusion in barium titanate and strontium titanate; Anionen- und Kationendiffusion in Barium- und Strontiumtitanat

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, Markus Franz

    2012-12-19

    Perovskite oxides show various interesting properties providing several technical applications. In many cases the defect chemistry is the key to understand and influence the material's properties. In this work the defect chemistry of barium titanate and strontium titanate is analysed by anion and cation diffusion experiments and subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS). The reoxidation equation for barium titanate used in multi-layer ceramic capacitors (MLCCs) is found out by a combination of different isotope exchange experiments and the analysis of the resulting tracer diffusion profiles. It is shown that the incorporation of oxygen from water vapour is faster by orders of magnitude than from molecular oxygen. Chemical analysis shows the samples contain various dopants leading to a complex defect chemistry. Dysprosium is the most important dopant, acting partially as a donor and partially as an acceptor in this effectively acceptor-doped material. TEM and EELS analysis show the inhomogeneous distribution of Dy in a core-shell microstructure. The oxygen partial pressure and temperature dependence of the oxygen tracer diffusion coefficients is analysed and explained by the complex defect chemistry of Dy-doped barium titanate. Additional fast diffusion profiles are attributed to fast diffusion along grain boundaries. In addition to the barium titanate ceramics from an important technical application, oxygen diffusion in cubic, nominally undoped BaTiO{sub 3} single crystals has been studied by means of {sup 18}O{sub 2}/{sup 16}O{sub 2} isotope exchange annealing and subsequent determination of the isotope profiles in the solid by ToF-SIMS. It is shown that a correct description of the diffusion profiles requires the analysis of the diffusion through the surface space-charge into the material's bulk. Surface exchange coefficients, space-charge potentials and bulk diffusion coefficients are analysed as a function of oxygen partial

  15. Landform Evolution Modeling of Specific Fluvially Eroded Physiographic Units on Titan

    Science.gov (United States)

    Moore, J. M.; Howard, A. D.; Schenk, P. M.

    2015-01-01

    Several recent studies have proposed certain terrain types (i.e., physiographic units) on Titan thought to be formed by fluvial processes acting on local uplands of bedrock or in some cases sediment. We have earlier used our landform evolution models to make general comparisons between Titan and other ice world landscapes (principally those of the Galilean satellites) that we have modeled the action of fluvial processes. Here we give examples of specific landscapes that, subsequent to modeled fluvial work acting on the surfaces, produce landscapes which resemble mapped terrain types on Titan.

  16. Titan Density Reconstruction Using Radiometric and Cassini Attitude Control Flight Data

    Science.gov (United States)

    Andrade, Luis G., Jr.; Burk, Thomas A.

    2015-01-01

    This paper compares three different methods of Titan atmospheric density reconstruction for the Titan 87 Cassini flyby. T87 was a unique flyby that provided independent Doppler radiometric measurements on the ground throughout the flyby including at Titan closest approach. At the same time, the onboard accelerometer provided an independent estimate of atmospheric drag force and density during the flyby. These results are compared with the normal method of reconstructing atmospheric density using thruster on-time and angular momentum accumulation. Differences between the estimates are analyzed and a possible explanation for the differences is evaluated.

  17. Effects of additives on microstructures of titanate based nanotubes prepared by the hydrothermal process

    International Nuclear Information System (INIS)

    Kubo, Takashi; Sugimoto, Keijiro; Onoki, Takamasa; Nakahira, Atsushi; Yamasaki, Yuki

    2009-01-01

    Silica-containing TiO 2 -derived titanate nanotubes were prepared by the addition of a small amount of tetraethyl orthosilicate (TEOS) to TiO 2 -derived titanate nanotubes prepared by the hydrothermal process and a subsequent heat-treatment at 473 K in air. The microstructure and thermal behavior of synthesized silica containing TiO 2 -derived titanate nanotubes were investigated by various methods such as X-ray diffraction (XRD), X-ray absorption fine structure (XAF), and X-ray photoelectron spectroscopy (XPS). As a result, the addition of a small amount of TEOS leaded to the improvement of the thermal stability for TiO 2 -derived titanate nanotubes. XPS results revealed that Si was combined onto the surface of TiO 2 -derived titanate nanotubes, forming partial Si-O-Ti chemical bonds. Therefore, it was inferred that the thermal stability could be modified by forming partial Si-O-Ti chemical bonds at interface of silica and TiO 2 -derived titanate nanotubes. (author)

  18. Influence of Applied Voltage and Film-Formation Time on Microstructure and Corrosion Resistance of Coatings Formed on Mg-Zn-Zr-Ca Bio-magnesium Alloy

    Science.gov (United States)

    Yandong, Yu; Shuzhen, Kuang; Jie, Li

    2015-09-01

    The influence of applied voltage and film-formation time on the microstructure and corrosion resistance of coatings formed on a Mg-Zn-Zr-Ca novel bio-magnesium alloy has been investigated by micro-arc oxidation (MAO) treatment. Phase composition and microstructure of as-coated samples were analyzed by the x-ray diffraction, energy dispersive x-ray spectroscopy and scanning electron microscopy. And the porosity and average of micro-pore aperture of the surface on ceramic coatings were analyzed by general image software. Corrosion microstructure of as-coated samples was caught by a microscope digital camera. The long-term corrosion resistance of as-coated samples was tested in simulated body fluid for 30 days. The results showed that the milky white smooth ceramic coating formed on the Mg-Zn-Zr-Ca novel bio-magnesium alloy was a compound of MgO, Mg2SiO4 and MgSiO3, and its corrosion resistance was significantly improved compared with that of the magnesium substrate. In addition, when the MAO applied voltage were 450 V and 500 V and film-formation time were 9 min and 11 min, the surface micro-morphology and the corrosion resistance of as-coated samples were relatively improved. The results provided a theoretical foundation for the application of the Mg-Zn-Zr-Ca novel bio-magnesium alloy in biomedicine.

  19. Characterization of barium titanate powder doped with sodium and potassium ions by using Rietveld refining; Caracterizacao do po de titanato de bario dopado com ions sodio e potasio com o refinamento de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, M.C.; Assis, J.T.; Pereira, F.R., E-mail: mcalixto@iprj.uerj.b [Universidade do Estado do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico; Araujo, J.C. [Universidade do Estado do Rio de Janeiro (FFP/UERJ), Sao Goncalo, RJ (Brazil). Fac. de Formacao de Professores; Moreira, E.L.; Moraes, V.C.A.; Lopes, A.R. [Centro Brasileiro de Pesquisas Fisicas (CBPF/MCT), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    A solid-reaction synthesis of doped barium titanate was done by employing barium carbonates, sodium, potassium and titanium oxides with classic procedures. Rietveld refining of X ray diffraction data of perovskite samples with tetragonal symmetry was applying and show good agreement. Besides, the treatment performed from 600 deg C produces nanocrystals of barium titanate with average size of 33 nm. The presence of endothermic peaks related to BaTiO{sub 3} formation at relatively low temperatures was determined by thermal analysis. A pseudo-Voigt Thompson-Cox-Hastings function was used to fit the standard samples of barium titanate. The Rietveld method has showed be efficient to detect the influences of temperature and doping on barium titanate microstructures. (author)

  20. Quality of Coated Particles : Physical - Mechanical Characterization of Polymeric Film Coatings

    NARCIS (Netherlands)

    Perfetti, G.

    2012-01-01

    All coated particle producers, when applying the coating layer(s) would like to know precisely what is the best coating system to use in order to answer customer’s requests. It is, therefore, of very high relevance for many industries, to have a clear understanding of what are the parameters I need

  1. Method and apparatus for coating thin foil with a boron coating

    Science.gov (United States)

    Lacy, Jeffrey L.

    2018-01-16

    An apparatus and a process is disclosed for applying a boron coating to a thin foil. Preferably, the process is a continuous, in-line process for applying a coating to a thin foil comprising wrapping the foil around a rotating and translating mandrel, cleaning the foil with glow discharge in an etching chamber as the mandrel with the foil moves through the chamber, sputtering the foil with boron carbide in a sputtering chamber as the mandrel moves through the sputtering chamber, and unwinding the foil off the mandrel after it has been coated. The apparatus for applying a coating to a thin foil comprises an elongated mandrel. Foil preferably passes from a reel to the mandrel by passing through a seal near the initial portion of an etching chamber. The mandrel has a translation drive system for moving the mandrel forward and a rotational drive system for rotating mandrel as it moves forward. The etching chamber utilizes glow discharge on a surface of the foil as the mandrel moves through said etching chamber. A sputtering chamber, downstream of the etching chamber, applies a thin layer comprising boron onto the surface of the foil as said mandrel moves through said sputtering chamber. Preferably, the coated foil passes from the mandrel to a second reel by passing through a seal near the terminal portion of the sputtering chamber.

  2. Titan: a distant but enticing destination for human visitors.

    Science.gov (United States)

    Nott, Julian

    2009-10-01

    Until recently, very little was known about Saturn's largest satellite, Titan. But that has changed dramatically since the Cassini spacecraft started orbiting in the Saturn system in 2004. Larger than Mercury and with a dense atmosphere, Titan has many of the characteristics of a planet. Indeed, many scientists now see it as the most interesting place in the Solar System for robotic exploration, with many unique features and even the possibility of exotic forms of life. This paper points out that Titan is also a potential destination for humans. With its predominantly nitrogen atmosphere, moderate gravity, and available water and oxygen, it also appears that, once it becomes possible to travel there, it will prove to be much more hospitable for human visitors than any other destination in the Solar System.

  3. Barium titanate thick films prepared by screen printing technique

    Directory of Open Access Journals (Sweden)

    Mirjana M. Vijatović

    2010-06-01

    Full Text Available The barium titanate (BaTiO3 thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i pure, ii doped with lanthanum and iii doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed.

  4. Implications of Wind-Assisted Aerial Navigation for Titan Mission Planning and Science Exploration

    Science.gov (United States)

    Elfes, A.; Reh, K.; Beauchamp, P.; Fathpour, N.; Blackmore, L.; Newman, C.; Kuwata, Y.; Wolf, M.; Assad, C.

    2010-01-01

    The recent Titan Saturn System Mission (TSSM) proposal incorporates a montgolfiere (hot air balloon) as part of its architecture. Standard montgolfiere balloons generate lift through heating of the atmospheric gases inside the envelope, and use a vent valve for altitude control. A Titan aerobot (robotic aerial vehicle) would have to use radioisotope thermoelectric generators (RTGs) for electric power, and the excess heat generated can be used to provide thermal lift for a montgolfiere. A hybrid montgolfiere design could have propellers mounted on the gondola to generate horizontal thrust; in spite of the unfavorable aerodynamic drag caused by the shape of the balloon, a limited amount of lateral controllability could be achieved. In planning an aerial mission at Titan, it is extremely important to assess how the moon-wide wind field can be used to extend the navigation capabilities of an aerobot and thereby enhance the scientific return of the mission. In this paper we explore what guidance, navigation and control capabilities can be achieved by a vehicle that uses the Titan wind field. The control planning approach is based on passive wind field riding. The aerobot would use vertical control to select wind layers that would lead it towards a predefined science target, adding horizontal propulsion if available. The work presented in this paper is based on aerodynamic models that characterize balloon performance at Titan, and on TitanWRF (Weather Research and Forecasting), a model that incorporates heat convection, circulation, radiation, Titan haze properties, Saturn's tidal forcing, and other planetary phenomena. Our results show that a simple unpropelled montgolfiere without horizontal actuation will be able to reach a broad array of science targets within the constraints of the wind field. The study also indicates that even a small amount of horizontal thrust allows the balloon to reach any area of interest on Titan, and to do so in a fraction of the time needed

  5. NIAC Phase 1 Final Study Report on Titan Aerial Daughtercraft

    Science.gov (United States)

    Matthies, Larry

    2017-01-01

    Saturns giant moon Titan has become one of the most fascinating bodies in the Solar System. Even though it is a billion miles from Earth, data from the Cassini mission reveals that Titan has a very diverse, Earth-like surface, with mountains, fluvial channels, lakes, evaporite basins, plains, dunes, and seas [Lopes 2010] (Figure 1). But unlike Earth, Titans surface likely is composed of organic chemistry products derived from complex atmospheric photochemistry [Lorenz 2008]. In addition, Titan has an active meteorological system with observed storms and precipitation-induced surface darkening suggesting a hydrocarbon cycle analogous to Earths water cycle [Turtle 2011].Titan is the richest laboratory in the solar system for studying prebiotic chemistry, which makes studying its chemistry from the surface and in the atmosphere one of the most important objectives in planetary science [Decadal 2011]. The diversity of surface features on Titan related to organic solids and liquids makes long-range mobility with surface access important [Decadal 2011]. This has not been possible to date, because mission concepts have had either no mobility (landers), no surface access (balloons and airplanes), or low maturity, high risk, and/or high development costs for this environment (e,g. large, self-sufficient, long-duration helicopters). Enabling in situ mobility could revolutionize Titan exploration, similarly to the way rovers revolutionized Mars exploration. Recent progress on several fronts has suggested that small-scale rotorcraft deployed as daughtercraft from a lander or balloon mothercraft may be an effective, affordable approach to expanding Titan surface access. This includes rapid progress on autonomous navigation capabilities of such aircraft for terrestrial applications and on miniaturization, driven by the consumer mobile electronics market, of high performance of sensors, processors, and other avionics components needed for such aircraft. Chemical analysis, for

  6. Experimental studies on 3D printing of barium titanate ceramics for medical applications

    Directory of Open Access Journals (Sweden)

    Schult Mark

    2016-09-01

    Full Text Available The present work deals with the 3D printing of porous barium titanate ceramics. Barium titanate is a biocompatible material with piezoelectric properties. Due to insufficient flowability of the starting material for 3D printing, the barium titanate raw material has been modified in three different ways. Firstly, barium titanate powder has been calcined. Secondly, flow additives have been added to the powder. And thirdly, flow additives have been added to the calcined powder. Finally, a polymer has been added to the three materials and specimens have been printed from these three material mixtures. The 3D printed parts were then sintered at 1320°C. The sintering leads to shrinkage which differs between 29.51–71.53% for the tested material mixtures. The porosity of the parts is beneficial for cell growth which is relevant for future medical applications. The results reported in this study demonstrate the possibility to fabricate porous piezoelectric barium titanate parts with a 3D printer that can be used for medical applications. 3D printed porous barium titanate ceramics can especially be used as scaffold for bone tissue engineering, where the bone formation can be promoted by electrical stimulation.

  7. The Michigan Titan Thermospheric General Circulation Model (TTGCM)

    Science.gov (United States)

    Bell, J. M.; Bougher, S. W.; de Lahaye, V.; Waite, J. H.

    2005-12-01

    The Cassini flybys of Titan since late October, 2004 have provided data critical to better understanding its chemical and thermal structures. With this in mind, a 3-D TGCM of Titan's atmosphere from 600km to the exobase (~1450km) has been developed. This paper presents the first results from the partially operational code. Currently, the TTGCM includes static background chemistry (Lebonnois et al 2001, Vervack et al 2004) coupled with thermal conduction routines. The thermosphere remains dominated by solar EUV forcing and HCN rotational cooling, which is calculated by a full line-by-line radiative transfer routine along the lines of Yelle (1991) and Mueller-Wodarg (2000, 2002). In addition, an approximate treatment of magnetospheric heating is explored. This paper illustrates the model's capabilities as well as some initial results from the Titan Thermospheric General Circulation model that will be compared with both the Cassini INMS data and the model of Mueller-Wodarg (2000,2002).

  8. A post-Cassini view of Titan's methane-based hydrologic cycle

    Science.gov (United States)

    Hayes, Alexander G.; Lorenz, Ralph D.; Lunine, Jonathan I.

    2018-05-01

    The methane-based hydrologic cycle on Saturn's largest moon, Titan, is an extreme analogue to Earth's water cycle. Titan is the only planetary body in the Solar System, other than Earth, that is known to have an active hydrologic cycle. With a surface pressure of 1.5 bar and temperatures of 90 to 95 K, methane and ethane condense out of a nitrogen-based atmosphere and flow as liquids on the moon's surface. Exchange processes between atmospheric, surface and subsurface reservoirs produce methane and ethane cloud systems, as well as erosional and depositional landscapes that have strikingly similar forms to their terrestrial counterparts. Over its 13-year exploration of the Saturn system, the Cassini-Huygens mission revealed that Titan's hydrocarbon-based hydrology is driven by nested methane cycles that operate over a range of timescales, including geologic, orbital (for example, Croll-Milankovitch cycles), seasonal and that of a single convective storm. In this Review Article, we describe the dominant exchange processes that operate over these timescales and present a post-Cassini view of Titan's methane-based hydrologic system.

  9. Co-crystal formation between two organic solids on the surface of Titan

    Science.gov (United States)

    Cable, M. L.; Vu, T. H.; Maynard-Casely, H. E.; Hodyss, R. P.

    2017-12-01

    Laboratory experiments of Titan molecular materials, informed by modeling, can help us to understand the complex and dynamic surface processes occurring on this moon at cryogenic temperatures. We previously demonstrated that two common organic materials on Titan, ethane and benzene, form a unique and stable co-crystalline structure at Titan surface temperatures. We have now characterized a second co-crystal that is stable on Titan, this time between two solids: acetylene and ammonia. The co-crystal forms within minutes at Titan surface temperature, as evidenced by new Raman spectral features in the lattice vibration and C-H bending regions. In addition, a red shift of the C-H stretching mode suggests that the acetylene-ammonia co-crystal is stabilized by a network of C-H···N interactions. Thermal stability studies indicate that this co-crystal remains intact to >110 K, and experiments with liquid methane and ethane reveal the co-crystal to be resistant to fluvial or pluvial exposure. Non-covalently bound structures such as these co-crystals point to far more complex surface interactions than previously believed on Titan. New physical and mechanical properties (deformation, plasticity, density, etc.), differences in storage of key species (i.e., ethane versus methane), variations in surface transport and new chemical gradients can all result in diverse surface features and chemistries of astrobiological interest.

  10. Titan's fluvial valleys: Morphology, distribution, and spectral properties

    Science.gov (United States)

    Langhans, M.H.; Jaumann, R.; Stephan, K.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Baines, K.H.; Nicholson, P.D.; Lorenz, R.D.; Soderblom, L.A.; Soderblom, J.M.; Sotin, Christophe; Barnes, J.W.; Nelson, R.

    2012-01-01

    Titan's fluvial channels have been investigated based on data obtained by the Synthetic Aperture Radar (SAR) instrument and the Visible and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. In this paper, a database of fluvial features is created based on radar-SAR data aiming to unveil the distribution and the morphologic and spectral characteristics of valleys on Titan on a global scale. It will also study the spatial relations between fluvial valleys and Titan's geologic units and spectral surface units which have become accessible thanks to Cassini-VIMS data. Several distinct morphologic types of fluvial valleys can be discerned by SAR-images. Dendritic valley networks appear to have much in common with terrestrial dendritic systems owing to a hierarchical and tree-shaped arrangement of the tributaries which is indicative of an origin from precipitation. Dry valleys constitute another class of valleys resembling terrestrial wadis, an indication of episodic and strong flow events. Other valley types, such as putative canyons, cannot be correlated with rainfall based on their morphology alone, since it cannot be ruled out that they may have originated from volcanic/tectonic action or groundwater sapping. Highly developed and complex fluvial networks with channel lengths of up to 1200 km and widths of up to 10 km are concentrated only at a few locations whereas single valleys are scattered over all latitudes. Fluvial valleys are frequently found in mountainous areas. Some terrains, such as equatorial dune fields and undifferentiated plains at mid-latitudes, are almost entirely free of valleys. Spectrally, fluvial terrains are often characterized by a high reflectance in each of Titan's atmospheric windows, as most of them are located on Titan's bright 'continents'. Nevertheless, valleys are spatially associated with a surface unit appearing blue due to its higher reflection at 1.3??m in a VIMS false color RGB composite with R: 1.59/1.27??m, G: 2

  11. The thermal structure of Titan's atmosphere

    Science.gov (United States)

    Mckay, Christopher P.; Pollack, James B.; Courtin, Regis

    1989-01-01

    The present radiative-convective model of the Titan atmosphere thermal structure obtains the solar and IR radiation in a series of spectral intervals with vertical resolution. Haze properties have been determined with a microphysics model encompassing a minimum of free parameters. It is determined that gas and haze opacity alone, using temperatures established by Voyager observations, yields a model that is within a few percent of the radiative convective balance throughout the Titan atmosphere. Model calculations of the surface temperature are generally colder than the observed value by 5-10 K; better agreement is obtained through adjustment of the model parameters. Sunlight absorption by stratospheric haze and pressure-induced gas opacity in the IR are the most important thermal structure-controlling factors.

  12. Composition and Performance of Nanostructured Zirconium Titanium Conversion Coating on Aluminum-Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Sheng-xue Yu

    2013-01-01

    Full Text Available Nanostructured conversion coating of Al-Mg alloy was obtained via the surface treatment with zirconium titanium salt solution at 25°C for 10 min. The zirconium titanium salt solution is composed of tannic acid 1.00 g·L−1, K2ZrF6 0.75 g·L−1, NaF 1.25 g·L−1, MgSO4 1.0 g/L, and tetra-n-butyl titanate (TBT 0.08 g·L−1. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR were used to characterize the composition and structure of the obtained conversion coating. The morphology of the conversion coating was obtained by atomic force microscopy (AFM and scanning electron microscopy (SEM. Results exhibit that the zirconium titanium salt conversion coating of Al-Mg alloy contains Ti, Zr, Al, F, O, Mg, C, Na, and so on. The conversion coating with nm level thickness is smooth, uniform, and compact. Corrosion resistance of conversion coating was evaluated in the 3.5 wt.% NaCl electrolyte through polarization curves and electrochemical impedance spectrum (EIS. Self-corrosion current density on the nanostructured conversion coating of Al-Mg alloy is 9.7×10-8A·cm-2, which is only 2% of that on the untreated aluminum-magnesium alloy. This result indicates that the corrosion resistance of the conversion coating is improved markedly after chemical conversion treatment.

  13. A Raman Study of Titanate Nanotubes | Liu | South African Journal ...

    African Journals Online (AJOL)

    The effect of the addition of NaOH or KOH on commercial Degussa Titania P25 was investigated using TEM, Raman and in situ Raman spectroscopy. Treatment of titania with conc. NaOH generated a tubular material corresponding to a sodium titanate. An in situ Raman study on the sodium titanate nanotubes as a function ...

  14. The dynamics in the upper atmospheres of Mars and Titan

    Science.gov (United States)

    Bell, Jared M.

    2008-06-01

    This thesis explores the dynamics of two terrestrial bodies: Mars and Titan. At Mars, the coupled Mars General Circulation Model - Mars Thermospheric General Circulation Model (MGCM-MTGCM) is employed to investigate the phenomenon known as Mars winter polar warming. At Titan, a new theoretical model, the Titan Global Ionosphere - Thermosphere Model (T-GITM), is developed, based upon previous work by Ridley et al. [2006]. Using this new model, three separate numerical studies quantify the impacts of solar cycle, seasons, and lower boundary zonal winds on the Titan thermosphere structure and dynamics. At Mars, this thesis investigates thermospheric winter polar warming through three major studies: (1) a systematic analysis of vertical dust mixing in the lower atmosphere and its impact upon the dynamics of the lower thermosphere (100-130 km), (2) an interannual investigation utilizing three years of lower atmosphere infrared (IR) dust optical depth data acquired by the Thermal Emission Spectrometer (TES) instrument on board Mars Global Surveyor (MGS), and finally (3) a brief study of the MTGCM's response to variations in upward propagating waves and tides from the lower atmosphere. Ultimately, this investigation suggests that an interhemispheric summer-to-winter Hadley circulation, originating in the lower atmosphere and extending into the upper atmosphere, is responsible for thermospheric winter polar warming [ Bell etal. , 2007]. A major branch of this thesis builds upon the previous work of Müller-Wodarg et al. [2000], Müller-Wodarg et al. [2003], M7uuml;ller-Wodarg et al. [2006], and Yelle et al. [2006] as it attempts to explain the structures in Titan's upper atmosphere, between 500-1500 km. Building also upon the recent development of GITM by Ridley et al. [2006], this thesis presents a new theoretical framework, T-GITM. This model is then employed to conduct a series of numerical experiments to quantify the impacts of the solar cycle, the season, and the

  15. Crystallinity and electrical properties of neodymium-substituted bismuth titanate thin films

    International Nuclear Information System (INIS)

    Chen, Y.-C.; Hsiung, C.-P.; Chen, C.-Y.; Gan, J.-Y.; Sun, Y.-M.; Lin, C.-P.

    2006-01-01

    We report on the properties of Nd-substituted bismuth titanate Bi 4-x Nd x Ti 3 O 12 (BNdT) thin films for ferroelectric non-volatile memory applications. The Nd-substituted bismuth titanate thin films fabricated by modified chemical solution deposition technique showed much improved properties compared to pure bismuth titanate. A pyrochlore free crystalline phase was obtained at a low annealing temperature of 640 deg. C and grain size was found to be considerably increased as the annealing temperature increased. The film properties were found to be strongly dependent on the Nd content and annealing temperatures. The measured dielectric constant of BNdT thin films was in the range 172-130 for Bi 4-x Nd x Ti 3 O 12 with x 0.0-0.75. Ferroelectric properties of Nd-substituted bismuth titanate thin films were significantly improved compared to pure bismuth titanate. For example, the observed 2P r and E c for Bi 3.25 Nd 0.75 Ti 3 O 12 , annealed at 680 deg. C, were 38 μC/cm 2 and 98 kV/cm, respectively. The improved microstructural and ferroelectric properties of BNdT thin films suggest their suitability for high density ferroelectric random access memory applications

  16. Spectroscopic detection and mapping of vinyl cyanide on Titan

    Science.gov (United States)

    Cordiner, Martin; Yukiko Palmer, Maureen; Lai, James; Nixon, Conor A.; Teanby, Nicholas; Charnley, Steven B.; Vuitton, Veronique; Kisiel, Zbigniew; Irwin, Patrick; Molter, Ned; Mumma, Michael J.

    2017-10-01

    The first spectroscopic detection of vinyl cyanide (otherwise known as acrylonitrile; C2H3CN) on Titan was obtained by Palmer et al. (2017), based on three rotational emission lines observed with ALMA at millimeter wavelengths (in receiver band 6). The astrobiological significance of this detection was highlighted due to the theorized ability of C2H3CN molecules to combine into cell membrane-like structures under the cold conditions found in Titan's hydrocarbon lakes. Here we report the detection of three additional C2H3CN transitions at higher frequencies (from ALMA band 7 flux calibration data). We present the first emission maps for this gas on Titan, and compare the molecular distribution with that of other nitriles observed with ALMA including HC3N, CH3CN, C2H5CN and HNC. The molecular abundance patterns are interpreted based on our understanding of Titan's high-altitude photochemistry and time-variable global circulation. Similar to the short-lived HC3N molecule, vinyl cyanide is found to be most abundant in the vicinity of the southern (winter) pole, whereas the longer-lived CH3CN is more concentrated in the north. The vertical abundance profile of C2H3CN (from radiative transfer modeling), as well as its latitudinal distribution, are consistent with a short photochemical lifetime for this species. Complementary results from our more recent (2017) nitrile mapping studies at higher spatial resolution will also be discussed.REFERENCES:Palmer, M. Y., Cordiner, M. A., Nixon, C. A. et al. "ALMA detection and astrobiological potential of vinyl cyanide on Titan", Sci. Adv. 2017, 3, e1700022

  17. Study of the dielectric properties of barium titanate-polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Pant, H.C. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Patra, M.K. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Verma, Aditya [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Vadera, S.R. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Kumar, N. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India)]. E-mail: nkjainjd@yahoo.com

    2006-07-15

    A comparative study of complex dielectric properties has been carried out at the X-band of microwave frequencies of composites of barium titanate (BaTiO{sub 3}) with two different polymer matrices: insulating polyaniline (PANI) powder (emeraldine base) and maleic resin. From these studies, it is observed that the composites of BaTiO{sub 3} with maleic resin show normal composite behavior and the dielectric constant follows the asymmetric Bruggeman model. In contrast, the composites of BaTiO{sub 3} with PANI show an unusual behavior wherein even at a low concentration of PANI (5 wt.%) there is a drastic reduction in the dielectric constant of BaTiO{sub 3}. This behavior of the dielectric constant is explained on the basis of coating of BaTiO{sub 3} particles by PANI which in turn is attributed to the highly surface adsorbing character. The materials have also been characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and optical microscopy studies.

  18. Big Impacts and Transient Oceans on Titan

    Science.gov (United States)

    Zahnle, K. J.; Korycansky, D. G.; Nixon, C. A.

    2014-01-01

    We have studied the thermal consequences of very big impacts on Titan [1]. Titan's thick atmosphere and volatile-rich surface cause it to respond to big impacts in a somewhat Earth-like manner. Here we construct a simple globally-averaged model that tracks the flow of energy through the environment in the weeks, years, and millenia after a big comet strikes Titan. The model Titan is endowed with 1.4 bars of N2 and 0.07 bars of CH4, methane lakes, a water ice crust, and enough methane underground to saturate the regolith to the surface. We assume that half of the impact energy is immediately available to the atmosphere and surface while the other half is buried at the site of the crater and is unavailable on time scales of interest. The atmosphere and surface are treated as isothermal. We make the simplifying assumptions that the crust is everywhere as methane saturated as it was at the Huygens landing site, that the concentration of methane in the regolith is the same as it is at the surface, and that the crust is made of water ice. Heat flow into and out of the crust is approximated by step-functions. If the impact is great enough, ice melts. The meltwater oceans cool to the atmosphere conductively through an ice lid while at the base melting their way into the interior, driven down in part through Rayleigh-Taylor instabilities between the dense water and the warm ice. Topography, CO2, and hydrocarbons other than methane are ignored. Methane and ethane clathrate hydrates are discussed quantitatively but not fully incorporated into the model.

  19. Corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by a sol-gel based silane coating filled with amino and isocyanate silane functionalized graphene oxide nanosheets

    Science.gov (United States)

    Parhizkar, Nafise; Ramezanzadeh, Bahram; Shahrabi, Taghi

    2018-05-01

    This research has focused on the effect of graphene oxide (GO) nano-fillers embedded in the sol-gel based silane coating on the corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by silane coatings. For this purpose, a mixture of Methyltriethoxysilane (MTES) and Tetraethylorthosilicate (TEOS) silane precursors was used for preparation of composite matrix and the GO nanosheets, which are covalently functionalized with 3-(Triethoxysilyl)propyl isocyanate (TEPI, IGO nano-fillers) and 3-aminopropyltriethoxysilane (APTES, AGO nano-fillers), were used as filler. The GO, AGO and IGO nanosheets were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible analysis and field emission-scanning electron microscopy techniques. The performance of the silane/epoxy coatings was investigated by pull-off adhesion, cathodic delamination, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results revealed that AGO and IGO nano-fillers significantly improved the corrosion resistance and adhesion properties of the top epoxy coating due to better compatibility with silane matrix, excellent barrier properties and the formation of covalent bonds with the top epoxy coating.

  20. Corrosion Resistance Properties of Aluminum Coating Applied by Arc Thermal Metal Spray in SAE J2334 Solution with Exposure Periods

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2016-03-01

    Full Text Available Arc thermal metal spray coating provides excellent corrosion, erosion and wear resistance to steel substrates. This paper incorporates some results of aluminum coating applied by this method on plain carbon steel. Thereafter, coated panels were exposed to an environment known to form stable corrosion products with aluminum. The coated panels were immersed in Society of Automotive Engineers (SAE J2334 for different periods of time. This solution consists of an aqueous solution of NaCl, CaCl2 and NaHCO3. Various electrochemical techniques, i.e., corrosion potential-time, electrochemical impedance spectroscopy (EIS and the potentiodynamic were used to determine the performance of stimulants in improving the properties of the coating. EIS studies revealed the kinetics and mechanism of corrosion and potentiodynamic attributed the formation of a passive film, which stifles the penetration of aggressive ions towards the substrate. The corrosion products that formed on the coating surface, identified using Raman spectroscopy, were Dawsonite (NaAlCO3(OH2 and Al(OH3. These compounds of aluminum are very sparingly soluble in aqueous solution and protect the substrate from pitting and uniform corrosion. The morphology and composition of corrosion products determined by scanning electron microscopy and energy dispersive X-ray analyses indicated that the environment plays a decisive role in improving the corrosion resistance of aluminum coating.

  1. Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics for capacitor applications

    Directory of Open Access Journals (Sweden)

    Zhang Chen

    2018-03-01

    Full Text Available Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics, prepared by solid state method, were investigated with non-stoichiometric level and various La2O3 content, using XRD, SEM and LCR measuring system. With an increase of non-stoichiometric level, the unit cell volumes of perovskite lattices for the single phase Ti-rich barium strontium titanate ceramics increased due to the decreasing A site vacancy concentration V″A. The unit cell volume increased and then decreased slightly with the increasing La2O3 content. Relatively high non-stoichiometric level and high La2O3 content in Ti-rich barium strontium titanate ceramics contributed to the decreased average grain size as well as fine grain size distribution, which correspondingly improved the temperature stability of the relative dielectric constant. The relative dielectric constant єrRT, dielectric loss tanδRT and the maximum relative dielectric constant єrmax decreased and then increased with the increasing non-stoichiometric level. With the increase of La2O3 doping content, the relative dielectric constant єrRT increased initially and then decreased. The maximum relative dielectric constant єrmax can be increased by applying low doping content of La2O3 in Ti-rich barium strontium titanate ceramics due to the increased spontaneous polarization.

  2. Titanic või turist? / Karin Paulus

    Index Scriptorium Estoniae

    Paulus, Karin, 1975-

    2006-01-01

    Tallinnas Tartu maanteel asuva endise Turisti poe (arhitektid Peep Jänes, Henno Sepmann) asemele tahavad hoone omanikud ehitada kõrghoone nimega Titanic. Hoone ajutine võtmine muinsuskaitse alla on põhjustanud kohtuvaidluse

  3. DETECTION OF PROPENE IN TITAN'S STRATOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Nixon, C. A.; Flasar, F. M. [Planetary Systems Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Jennings, D. E. [Detector Systems Branch, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bézard, B.; Vinatier, S.; Coustenis, A. [LESIA, Observatoire de Paris, CNRS, 5 Place Jules Janssen, F-92195 Meudon Cedex (France); Teanby, N. A. [School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen' s Road, Bristol BS8 1RJ (United Kingdom); Sung, K. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, CA 91109 (United States); Ansty, T. M. [Department of Space Science, Cornell University, Ithaca, NY 14853 (United States); Irwin, P. G. J. [Atmospheric, Oceanic and Planetary Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom); Gorius, N. [IACS, Catholic University of America, Washington, DC 20064 (United States); Cottini, V. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2013-10-10

    The Voyager 1 flyby of Titan in 1980 gave a first glimpse of the chemical complexity of Titan's atmosphere, detecting many new molecules with the infrared interferometer spectrometer (IRIS). These included propane (C{sub 3}H{sub 8}) and propyne (CH{sub 3}C{sub 2}H), while the intermediate-sized C{sub 3}H {sub x} hydrocarbon (C{sub 3}H{sub 6}) was curiously absent. Using spectra from the Composite Infrared Spectrometer on Cassini, we show the first positive detection of propene (C{sub 3}H{sub 6}) in Titan's stratosphere (5σ significance), finally filling the three-decade gap in the chemical sequence. We retrieve a vertical abundance profile from 100-250 km, that varies slowly with altitude from 2.0 ± 0.8 ppbv at 125 km, to 4.6 ± 1.5 ppbv at 200 km. The abundance of C{sub 3}H{sub 6} is less than both C{sub 3}H{sub 8} and CH{sub 3}C{sub 2}H, and we remark on an emerging paradigm in Titan's hydrocarbon abundances whereby alkanes > alkynes > alkenes within the C{sub 2}H {sub x} and C{sub 3}H {sub x} chemical families in the lower stratosphere. More generally, there appears to be much greater ubiquity and relative abundance of triple-bonded species than double-bonded, likely due to the greater resistance of triple bonds to photolysis and chemical attack.

  4. Non-LTE diagnositics of infrared radiation of Titan's atmosphere

    Science.gov (United States)

    Feofilov, Artem; Rezac, Ladislav; Kutepov, Alexander; Vinatier, Sandrine; Rey, Michael; Nikitin, Andrew; Tyuterev, Vladimir

    2016-06-01

    Yelle (1991) and Garcia-Comas et al, (2011) demonstrated the importance of accounting for the local thermodynamic equilibrium (LTE) breakdown in the middle and upper atmosphere of Titan for the interpretation of infrared radiances measured at these heights. In this work, we make further advance in this field by: • updating the non-LTE model of CH4 emissions in Titan's atmosphere and including a new extended database of CH4 spectroscopic parameters • studying the non-LTE CH4 vibrational level populations and the impact of non-LTE on limb infrared emissions of various CH4 ro-vibrational bands including those at 7.6 and 3.3 µm • implementing our non-LTE model into the LTE-based retrieval algorithm applied by Vinatier et al., (2015) for processing the Cassini/CIRS spectra. We demonstrate that accounting for non-LTE leads to an increase in temperatures retrieved from CIRS 7.6 µm limb emissions spectra (˜10 K at 600 km altitude) and estimate how this affects the trace gas density retrieval. Finally, we discuss the effects of including a large number of weak one-quantum and combinational bands on the calculated daytime limb 3.3 µm emissions and the impact they may have on the CH4 density retrievals from the Cassini VIMS 3.3 µm limb emission observations.

  5. Humidity control and hydrophilic glue coating applied to mounted protein crystals improves X-ray diffraction experiments

    International Nuclear Information System (INIS)

    Baba, Seiki; Hoshino, Takeshi; Ito, Len; Kumasaka, Takashi

    2013-01-01

    A new crystal-mounting method has been developed that involves a combination of controlled humid air and polymer glue for crystal coating. This method is particularly useful when applied to fragile protein crystals that are known to be sensitive to subtle changes in their physicochemical environment. Protein crystals are fragile, and it is sometimes difficult to find conditions suitable for handling and cryocooling the crystals before conducting X-ray diffraction experiments. To overcome this issue, a protein crystal-mounting method has been developed that involves a water-soluble polymer and controlled humid air that can adjust the moisture content of a mounted crystal. By coating crystals with polymer glue and exposing them to controlled humid air, the crystals were stable at room temperature and were cryocooled under optimized humidity. Moreover, the glue-coated crystals reproducibly showed gradual transformations of their lattice constants in response to a change in humidity; thus, using this method, a series of isomorphous crystals can be prepared. This technique is valuable when working on fragile protein crystals, including membrane proteins, and will also be useful for multi-crystal data collection

  6. Humidity control and hydrophilic glue coating applied to mounted protein crystals improves X-ray diffraction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Seiki; Hoshino, Takeshi; Ito, Len; Kumasaka, Takashi, E-mail: kumasaka@spring8.or.jp [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2013-09-01

    A new crystal-mounting method has been developed that involves a combination of controlled humid air and polymer glue for crystal coating. This method is particularly useful when applied to fragile protein crystals that are known to be sensitive to subtle changes in their physicochemical environment. Protein crystals are fragile, and it is sometimes difficult to find conditions suitable for handling and cryocooling the crystals before conducting X-ray diffraction experiments. To overcome this issue, a protein crystal-mounting method has been developed that involves a water-soluble polymer and controlled humid air that can adjust the moisture content of a mounted crystal. By coating crystals with polymer glue and exposing them to controlled humid air, the crystals were stable at room temperature and were cryocooled under optimized humidity. Moreover, the glue-coated crystals reproducibly showed gradual transformations of their lattice constants in response to a change in humidity; thus, using this method, a series of isomorphous crystals can be prepared. This technique is valuable when working on fragile protein crystals, including membrane proteins, and will also be useful for multi-crystal data collection.

  7. Titan Ice and Dust Experiment (TIDE): Detection and Analysis of Compounds of Interest to Astrobiology in the Lower Atmosphere and Surface of Titan

    Science.gov (United States)

    Kojiro, Daniel R.; Holland Paul M.; Stimac, Robert M.; Kaye, William J.; Takeruchi, Noreshige

    2004-01-01

    The Titan Orbiter Aerorover Mission (TOAM) is a proposed concept for the Solar System Exploration Visions Mission, Titan Explorer, a follow-on to the Cassini-Huygens mission. TOAM would use a Titan polar orbiter and a lighter-than-air aerorover to investigate the surface and atmosphere of Titan. Astrobiology issues will be addressed though TOAM investigations including, for example: Distribution and composition of organics (atmospheric, aerosol, surface); Organic chemical processes, their chemical context and energy sources; and Seasonal variations and interactions of the atmosphere and surface. The TIDE instrument will perform in-situ analyses to obtain comprehensive and sensitive molecular and elemental assays of volatile organics in the atmosphere, oceans and surface. TIDE chemical analyses are conducted by a Gas Chromatograph-Ion Mobility Spectrometer (GC-IMS). This TIDE GC-IMS was a component of the mini-Cometary Ice and Dust Experiment (mini-CIDEX) developed for the chemical analysis of a cometary environment. Both the GC and helium IMS of mini-CIDEX have been further developed to better meet the analytical and operational requirements of the TOAM. application. A Micro-ElectroMechanical System (MEMS) GC and Mini-Cell helium IMS are under development to replace their respective mini-CIDEX components, providing similar or advanced analytical capabilities.

  8. Formation of chemical compounds under vacuum plasma-arc deposition of nickel and its alloy onto piezoceramics

    International Nuclear Information System (INIS)

    Grinchenko, V.T.; Lyakhovich, T.K.; Prosina, N.I.; Khromov, S.M.

    1988-01-01

    The phase composition of the transition layer appearing during vacuum-arc coating of nickel and nickel alloy with copper on barium titanate and lead zirconate-titanate is identified. During vacuum plasma-arc coating of nickel and its alloy at the boundary with barium titanate and lead zirconate-titanate the Ni 2 Ti 4 O compound appears which has the crystal lattice type identical with substrate with the parity of lattice parameters. The transition layer contains nickel oxides and NiTiO 3 in the case of barium titanate. When titanate content in substrate increases the zone of reaction diffusion increases in value and becomes more complicate in composition

  9. Aluminum titanate crucible for molten uranium

    International Nuclear Information System (INIS)

    Asbury, J.J.

    1975-01-01

    An improved crucible for molten uranium is described. The crucible or crucible liner is formed of aluminum titanate which essentially eliminates contamination of uranium and uranium alloys during molten states thereof. (U.S.)

  10. The effect of graphene oxide on surface features, biological performance and bio-stability of calcium phosphate coating applied by pulse electrochemical deposition

    Science.gov (United States)

    Fathyunes, Leila; Khalil-Allafi, Jafar

    2018-04-01

    In the current study, the effect of second phase of graphene oxide (GO) on the surface features and biological behavior of calcium phosphate (CaP) coating was evaluated. To do so, the GO-CaP composite coating was applied on TiO2 nanotubular arrays using pulse electrochemical deposition. The SEM and AFM images showed that, the CaP-based coating with uniform and refined microstructure could be formed through its compositing with GO sheets. The biological assessment of the coatings was also conducted by cell culture test and MTT assay. Based on findings, the GO-CaP coating showed the better biocompatibility compared to the CaP coating. This could be owing to the fact that the composite coating provided the lower roughness, moderately wettable surface with a contact angle of 23.5° ± 2.6° and the higher stability in the biological environments because of being involved with only the stable phase of CHA. However, in the CaP coating, spreading of cells could be limited by the plate-like crystals with larger size. The higher solubility of the CaP coating in the cell culture medium possibly owing to the existence of some metastable CaP phases like OCP in addition to the dominant phase of CHA in this coating could be another reason for its less biocompatibility. At last, the CaP coating showed the higher apatite-forming ability in SBF solution after its compositing with GO.

  11. Syntheses, Structures, and Magnetic Properties of Nickel-Doped Lepidocrocite Titanates

    DEFF Research Database (Denmark)

    Gao, Tao; Norby, Poul; Okamoto, Hiroshi

    2009-01-01

    Ni-doped titanate CsxTi2−x/2Nix/2O4 and its protonic derivative HxTi2−x/2Nix/2O4·xH2O (x = 0.7) were synthesized and characterized by means of synchrotron X-ray diffraction, Raman scattering, X-ray photoelectron spectroscopy (XPS), and magnetic measurements. CsxTi2−x/2Nix/2O4 crystallizes......H2O. Ni- and Mg-codoped titanates CsxTi2−x/2(NiyMg1−y)x/2O4 (x = 0.7, 0 ≤ y ≤ 1) were also reported. The crystal structure, interlayer chemistry, and magnetic properties of the titanates depend on the Ni substitution levels, indicating opportunities for tuning of the properties by controlling...

  12. Synergism of Saturn, Enceladus and Titan and Formation of HCNO Prebiotic Molecules

    Science.gov (United States)

    Sittler, Edward C.; Cooper, John F.

    2011-01-01

    Saturn as a system has two very exotic moons Titan and Enceladus. Titan, taking in energy from Saturn's magnetosphere, solar UV irradiation, and cosmic rays, can make HCN based molecules as discussed in earlier paper by Raulin and Owen. Space radiation effects at both moons, and as coupled by the Saturn magnetosphere, could cause an unexpected series of events potentially leading to prebiotic chemical evolution at Titan with HCNO from magnetospheric oxygen as the new ingredient. The "Old Faithful" model suggests that Enceladus, highly irradiated by Saturn magnetospheric electrons and thus having a source of chemical energy from radiolytic gas production, has episodic ejections of water vapor, carbon dioxide, and various hydrocarbons into Saturn's magnetosphere. The hydrocarbons do not survive transport through the plasma environment, but oxygen ions from Enceladus water molecules become the dominant ion species in the outer magnetosphere. At Titan, Cassini discovered that 1) keV oxygen ions, evidently from Enceladus, are bombarding Titan's upper atmosphere and 2) heavy positive and negative ions exist in significant abundances within Titan's upper atmosphere. Initial models of heavy ion formation in Titan's upper atmosphere invoked polymerization of aromatics such as benzenes and their radicals to make polycyclic aromatic hydrocarbons (PAH) , while a more recent model by Sittler et al., has raised the possibility of carbon chains forming from the polymerization of acetylene and its radicals to make fullerenes. Laboratory measurements indicate that fullerenes, which are hollow carbon shells, can trap keV oxygen ions. Clustering of the fullerenes with aerosol mixtures from PAHs and the dominant nitrogen molecules could form larger aerosols enriched in trapped oxygen. Aerosol precipitation could then convey these chemically complex structures deeper into the atmosphere and to the moon surface. Ionizing solar UV, magnetospheric electron, and galactic cosmic ray

  13. Integration of PanDA workload management system with Titan supercomputer at OLCF

    Science.gov (United States)

    De, K.; Klimentov, A.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Schovancova, J.; Vaniachine, A.; Wenaus, T.

    2015-12-01

    The PanDA (Production and Distributed Analysis) workload management system (WMS) was developed to meet the scale and complexity of LHC distributed computing for the ATLAS experiment. While PanDA currently distributes jobs to more than 100,000 cores at well over 100 Grid sites, the future LHC data taking runs will require more resources than Grid computing can possibly provide. To alleviate these challenges, ATLAS is engaged in an ambitious program to expand the current computing model to include additional resources such as the opportunistic use of supercomputers. We will describe a project aimed at integration of PanDA WMS with Titan supercomputer at Oak Ridge Leadership Computing Facility (OLCF). The current approach utilizes a modified PanDA pilot framework for job submission to Titan's batch queues and local data management, with light-weight MPI wrappers to run single threaded workloads in parallel on Titan's multicore worker nodes. It also gives PanDA new capability to collect, in real time, information about unused worker nodes on Titan, which allows precise definition of the size and duration of jobs submitted to Titan according to available free resources. This capability significantly reduces PanDA job wait time while improving Titan's utilization efficiency. This implementation was tested with a variety of Monte-Carlo workloads on Titan and is being tested on several other supercomputing platforms. Notice: This manuscript has been authored, by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

  14. A Model of Titan-like Chemistry to Connect Experiments and Cassini Observations

    Science.gov (United States)

    Raymond, Alexander W.; Sciamma-O’Brien, Ella; Salama, Farid; Mazur, Eric

    2018-02-01

    A numerical model is presented for interpreting the chemical pathways that lead to the experimental mass spectra acquired in the Titan Haze Simulation (THS) laboratory experiments and for comparing the electron density and temperature of the THS plasma to observations made at Titan by the Cassini spacecraft. The THS plasma is a pulsed glow-discharge experiment designed to simulate the reaction of N2/CH4-dominated gas in Titan's upper atmosphere. The transient, one-dimensional model of THS chemistry tracks the evolution of more than 120 species in the direction of the plasma flow. As the minor species C2H2 and C2H4 are added to the N2/CH4-based mixture, the model correctly predicts the emergence of reaction products with up to five carbon atoms in relative abundances that agree well with measured mass spectra. Chemical growth in Titan's upper atmosphere transpires through ion–neutral and neutral–neutral chemistry, and the main reactions involving a series of known atmospheric species are retrieved from the calculation. The model indicates that the electron density and chemistry are steady during more than 99% of the 300 μs long discharge pulse. The model also suggests that the THS ionization fraction and electron temperature are comparable to those measured in Titan's upper atmosphere. These findings reaffirm that the THS plasma is a controlled analog environment for studying the first and intermediate steps of chemistry in Titan's upper atmosphere.

  15. The MR-TOF-MS isobar separator for the TITAN facility at TRIUMF

    Science.gov (United States)

    Jesch, Christian; Dickel, Timo; Plaß, Wolfgang R.; Short, Devin; Ayet San Andres, Samuel; Dilling, Jens; Geissel, Hans; Greiner, Florian; Lang, Johannes; Leach, Kyle G.; Lippert, Wayne; Scheidenberger, Christoph; Yavor, Mikhail I.

    2015-11-01

    At TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) will extend TITAN's capabilities and facilitate mass measurements and in-trap decay spectroscopy of exotic nuclei that so far have not been possible due to strong isobaric contamination. This MR-TOF-MS will also enable mass measurements of very short-lived nuclides (half-life > 1 ms) that are produced in very low quantities (a few detected ions overall). In order to allow the installation of an MR-TOF-MS in the restricted space on the platform, on which the TITAN facility is located, novel mass spectrometric methods have been developed. Transport, cooling and distribution of the ions inside the device is done using a buffer gas-filled RFQ-based ion beam switchyard. Mass selection is achieved using a dynamic retrapping technique after time-of-flight analysis in an electrostatic isochronous reflector system. Only due to the combination of these novel methods the realization of an MR-TOF-MS based isobar separator at TITAN has become possible. The device has been built, commissioned off-line and is currently under installation at TITAN.

  16. Iron-catalyzed oxidative biaryl cross-couplings via mixed diaryl titanates: significant influence of the order of combining aryl Grignard reagents with titanate.

    Science.gov (United States)

    Liu, Kun Ming; Wei, Juan; Duan, Xin Fang

    2015-03-18

    The mixed diaryl titanates were used for the first time to modify the reactivity of two aryl Grignard reagents. Two titanate intermediates, Ar[Ar'Ti(OR)3]MgX and Ar'[ArTi(OR)3]MgX, formed via alternating the sequence of combining Grignard reagents with ClTi(OR)3 showed a significant reactivity difference. Taking advantage of such different reactivity, two highly structurally similar aryl groups could be facilely assembled through iron-catalyzed oxidative cross-couplings using oxygen as the oxidant.

  17. Ultrafast carrier dynamics of titanic acid nanotubes investigated by transient absorption spectroscopy.

    Science.gov (United States)

    Wang, Li; Zhao, Hui; Pan, Lin Yun; Weng, Yu Xiang; Nakato, Yoshihiro; Tamai, Naoto

    2010-12-01

    Carrier dynamics of titanic acid nanotubes (phase of H2Ti2O5.H2O) deposited on a quartz plate was examined by visible/near-IR transient absorption spectroscopy with an ultraviolet excitation. The carrier dynamics of titanic acid nanotubes follows the fast trapping process which attributed to the intrinsic tubular structure, the relaxation of shallow trapped carriers and the recombination as a second-order kinetic process. Transient absorption of titanic acid nanotubes was dominated by the absorption of surface-trapped holes in visible region around 500 nm, which was proved by the faster decay dynamics in the presence of polyvinyl alcohol as a hole-scavenger. However, the slow relaxation of free carriers was much more pronounced in the TiO2 single crystals, as compared with the transient absorption spectra of titanic acid nanotubes under the similar excitation.

  18. Heat capacity measurements on dysprosium titanate

    International Nuclear Information System (INIS)

    Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.

    2014-01-01

    Dysprosium titanate is considered as a candidate material for use in the control rods of future nuclear reactors. The Dy 2 TiO 5 compound was prepared by solid-state synthesis and characterized by XRD technique. The high temperature enthalpy increments of dysprosium titanates have been measured for the first time by employing the method of inverse drop calorimetry in the temperature range 748-1645 K by using high temperature drop calorimeter. The calorimeter, the method of measurement and the procedure adopted for enthalpy increment measurements and analysis of the measured data to compute thermodynamic functions have been described elsewhere. The measured enthalpy increments were fitted to polynomial in temperature by using the least squares method. The fit equation in the temperature range from 298 to 1800 K is given

  19. Development of Strontium Titanate Thin films on Technical Substrates for Superconducting Coated Conductors

    DEFF Research Database (Denmark)

    Pallewatta, Pallewatta G A P; Yue, Zhao; Grivel, Jean-Claude

    2012-01-01

    SrTiO3 is a widely studied perovskite material due to its advantages as a template for high temperature superconducting tapes. Heteroepitaxial SrTiO3 thin films were deposited on Ni/W tapes using dip-coating in a precursor solution followed by drying and annealing under reducing conditions. Nearl...

  20. Inductive thermal plasma generation applied for the materials coating

    International Nuclear Information System (INIS)

    Pacheco, J.; Pena, R.; Cota, G.; Segovia, A.; Cruz, A.

    1996-01-01

    The coatings by thermal plasma are carried out introducing particles into a plasma system where they are accelerated and melted (total or partially) before striking the substrate to which they adhere and are suddenly cooled down. The nature of consolidation and solidification of the particles allows to have control upon the microstructure of the deposit. This technique is able to deposit any kind of material that is suitable to be merged (metal, alloy, ceramic, glass) upon any type of substrate (metal, graphite, ceramic, wood) with an adjustable thickness ranging from a few microns up to several millimeters. The applications are particularly focused to the coating of materials in order to improve their properties of resistance to corrosion, thermal and mechanical efforts as well as to preserve the properties of the so formed compound. In this work the electromagnetic induction phenomenon in an ionized medium by means of electric conductivity, is described. Emphasis is made on the devices and control systems employed in order to generate the thermal plasma and in carrying out the coatings of surfaces by the projection of particles based on plasma

  1. Strontium titanate thin film deposition - structural and electronical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hanzig, Florian; Hanzig, Juliane; Stoecker, Hartmut; Mehner, Erik; Abendroth, Barbara; Meyer, Dirk C. [TU Bergakademie Freiberg, Institut fuer Experimentelle Physik (Germany); Franke, Michael [TU Bergakademie Freiberg, Institut fuer Elektronik- und Sensormaterialien (Germany)

    2012-07-01

    Strontium titanate is on the one hand a widely-used model oxide for solids which crystallize in perovskite type of structure. On the other hand, with its large band-gap energy and its mixed ionic and electronic conductivity, SrTiO{sub 3} is a promising isolating material in metal-insulator-metal (MIM) structures for resistive switching memory cells. Here, we used physical vapour deposition methods (e. g. electron-beam and sputtering) to produce strontium titanate layers. Sample thicknesses were probed with X-ray reflectometry (XRR) and spectroscopic ellipsometry (SE). Additionally, layer densities and dielectric functions were quantified with XRR and SE, respectively. Using infrared spectroscopy free electron concentrations were obtained. Phase and element composition analysis was carried out with grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. Subsequent temperature treatment of samples lead to crystallization of the initially amorphous strontium titanate.

  2. Numerical study on lithium titanate battery thermal response under adiabatic condition

    International Nuclear Information System (INIS)

    Sun, Qiujuan; Wang, Qingsong; Zhao, Xuejuan; Sun, Jinhua; Lin, Zijing

    2015-01-01

    Highlights: • The thermal behavior of lithium titanate battery during cycling was investigated. • The temperature rate in charging was less than that of discharging in the cycling. • The temperature difference was less than 0.02 °C at 0.5 C in adiabatic condition. • The temperature distribution and thermal runaway of the battery were predicted. - Abstract: To analyze the thermal behavior of 945 mA h lithium titanate battery during charging and discharging processes, the experimental and numerical studies are performed in this work. The cathode and anode of the 945 mA h lithium titanate soft package battery are the lithium nickel–cobalt–manganese-oxide and lithium titanate, respectively. In the experiment, an Accelerating Rate Calorimeter combined with battery cycler is employed to investigate the electrochemical–thermal behavior during charge–discharge cycling under the adiabatic condition. In numerical simulation, one electrochemical-thermal model is adopted to predict the thermal response and validated with the experimental results. From both experimental and simulated results, the profile of potential and current, the heat generation, the temperature, the temperature changing rate and the temperature distribution in the cell are obtained and thermal runaway is predicted. The analysis of the electrochemical and thermal behavior is beneficial for the commercial application of lithium titanate battery in the fields of electric vehicles and hybrid electric vehicles

  3. Behaviour of solid phase ethyl cyanide in simulated conditions of Titan

    Science.gov (United States)

    Couturier-Tamburelli, I.; Toumi, A.; Piétri, N.; Chiavassa, T.

    2018-01-01

    In order to simulate different altitudes in the atmosphere of Titan, we investigated using infrared spectrometry and mass spectrometry the photochemistry of ethyl cyanide (CH3CH2CN) ices at different temperatures. Heating experiments of the solid phase until complete desorption showed up three phase transitions with a first one appearing to be approximately at the temperature of Titan's surface (94 K), measured by the Huygens probe. Ethyl cyanide, whose presence has been suggested in solid phase in Titan, can be considered as another nitrile for photochemical models of the Titan atmosphere after our first study (Toumi et al., 2016) concerning vinyl cyanide (CH2CHCN). The desorption energy of ethyl cyanide has been calculated to be 36.75 ( ± 0.55) kJ mol-1 using IRTF and mass spectroscopical techniques. High energetic photolysis (λ > 120 nm) have been performed and we identified ethyl isocyanide, vinyl cyanide, cyanoacetylene, ethylene, acetylene, cyanhydric acid and a methylketenimine form as photoproducts from ethyl cyanide. The branching ratios of the primary products were determined at characteristic temperatures of Titan thanks to the value of the νCN stretching band strength of ethyl cyanide that has been calculated to be 4.12 × 10-18 cm molecule-1. We also report here for the first time the values of the photodissociation cross sections of C2H5CN for different temperatures.

  4. In situ Sn2+-incorporation synthesis of titanate nanotubes for photocatalytic dye degradation under visible light illumination

    International Nuclear Information System (INIS)

    Tsai, Chien-Cheng; Chen, Liang-Che; Yeh, Te-Fu; Teng, Hsisheng

    2013-01-01

    Highlights: ► Sn 2+ ions sensitize titanate nanotubes for photocatalysis under visible-light illumination. ► The Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanates. ► The presence of Sn 2+ lifts the valence band of titanate nanotubes by approximately 0.9 eV. ► The doped Sn 2+ sites are active in donating photo-induced charges to dye degradation. - Abstract: Sn 2+ -incorporated titanate nanotubes, prepared by washing a layered sodium titanate with a SnCl 2 solution for tube formation, exhibit noticeable photocatalytic activity under visible light irradiation. This in situ synthesis results in a Sn/Ti ratio of approximately 0.6. Because of the introduction of Sn 2+ ions, the Sn 5s orbital replaces the O 2p orbital as the top level of the valence band of titanate nanotubes. Optical absorption analysis shows that Sn doping reduces the bandgap of titanate nanotubes from 3.5 to 2.6 eV. Oxidation of the Sn 2+ -incorporated titanate nanotubes leads to oxidation of Sn 2+ to Sn 4+ , hence, widening the bandgap. Under visible light irradiation, Sn 2+ -incorporated titanate nanotubes effectively degrade methylene blue in an aqueous solution, whereas the bare titanate nanotubes exhibit substantially lower photocatalytic activity. Photoluminescence analysis demonstrates that the induced charges from excitation of the Sn 2+ ions tend to be relaxed through chemical interactions, rather than irradiative recombination.

  5. Partially collisional model of the Titan hydrogen torus

    International Nuclear Information System (INIS)

    Hilton, D.A.

    1987-01-01

    A numerical model was developed for atomic hydrogen densities in the Titan hydrogen torus. The effects of occasional collisions were included in order to accurately simulate physical conditions inferred from the Voyager 1 and 2 Ultraviolet Spectrometer (UVS) results of Broadfoot et al. (1981) and Sandel et al. (1982). The model employed Lagrangian perturbation of orbital elements of hydrogen atoms launched from Titan and Monte Carlo simulation of collisions and loss mechanisms. The torus is found to be azimuthally symmetric with the density sharply peaked at Titan's orbit, and decreasing rapidly in the outward and perpendicular directions and more gradually inward from 17 to 5 R/sub s/. The energetic hydrogen atoms from Saturn's upper atmosphere, first predicted by Shemansky and Smith (1982), were also investigated. Collisions of these Saturnian atoms with the torus population do not contribute to the torus density, and will lead to a net loss of torus atoms if their launch speeds from Saturn extend above 40 km/sec. The Saturnian atoms produce a corona which was modeled using the theory of Chamberlain (1963)

  6. Titan Exploration Using a Radioisotopically-Heated Montgolfiere Balloon

    Science.gov (United States)

    Elliott, John O.; Reh, Kim; Spilker, Tom

    2007-01-01

    This paper describes results of a recent Titan exploration mission study; one which includes an aerial vehicle in the form of a hot air balloon, or montgolfiere. Unlike terrestrial montgolfieres which require burning fuel, the dual use of MMRTGs to provide a continuous source of heat as well as electrical power would give the balloon an inherent ability to float for a very long time in the atmosphere of Titan. It would ride with the easterly winds at a cruising altitude of about 10,000 km, occasionally changing altitude to take advantage of possible reverse wind directions and even descending to the surface to physically sample sites of interest. Seasonal and tidal north-south winds would allow the mission to explore different latitudes, which Cassini data have shown to be amazingly diverse in geologic nature. Communication from the aerial vehicle would be relayed through an accompanying orbiter spacecraft, as well as transmitted directly to Earth, providing the potential for data return from Titan's surface equivalent to that provided by many comparable orbiter missions at much closer destinations.

  7. Dielectric characterization of low-loss calcium strontium titanate fibers produced by laser floating zone technique for wireless communication

    International Nuclear Information System (INIS)

    Amaral, F.; Valente, M.A.; Costa, L.C.; Costa, F.M.

    2014-01-01

    Wireless communication technology assisted to a huge development during the last two decades, responding to the growing demand for small size and low weight devices such as cell phones and global positioning systems. The need for miniaturization and higher autonomy resulted in the development of new dielectric oxide ceramics with very specific properties, to be applied as dielectric resonators in filters, oscillators, and antennas. Some crucial properties as a high quality factor, high dielectric constant, and near zero temperature coefficient of resonant frequency must be considered during the selection of the appropriate materials. The present work deals with the preparation of calcium titanate (CaTiO 3 ), strontium titanate (SrTiO 3 ), and calcium strontium titanate (Ca x Sr 1-x TiO 3 ) fibers produced by laser floating zone (LFZ) technique. Our results show that fibers grown at lower pulling rates exhibit higher ε', for all the studied frequency range, including the microwave region. Moreover, the quality factor is always high envisaging the possibility to include these materials in future wireless device applications. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Dielectric characterization of low-loss calcium strontium titanate fibers produced by laser floating zone technique for wireless communication

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, F. [Department of Physics and I3N, University of Aveiro, 3810-193, Aveiro (Portugal); Polytechnic Institute of Coimbra, 3000-271, Coimbra (Portugal); Valente, M.A.; Costa, L.C.; Costa, F.M. [Department of Physics and I3N, University of Aveiro, 3810-193, Aveiro (Portugal)

    2014-09-15

    Wireless communication technology assisted to a huge development during the last two decades, responding to the growing demand for small size and low weight devices such as cell phones and global positioning systems. The need for miniaturization and higher autonomy resulted in the development of new dielectric oxide ceramics with very specific properties, to be applied as dielectric resonators in filters, oscillators, and antennas. Some crucial properties as a high quality factor, high dielectric constant, and near zero temperature coefficient of resonant frequency must be considered during the selection of the appropriate materials. The present work deals with the preparation of calcium titanate (CaTiO{sub 3}), strontium titanate (SrTiO{sub 3}), and calcium strontium titanate (Ca{sub x}Sr{sub 1-x}TiO{sub 3}) fibers produced by laser floating zone (LFZ) technique. Our results show that fibers grown at lower pulling rates exhibit higher ε', for all the studied frequency range, including the microwave region. Moreover, the quality factor is always high envisaging the possibility to include these materials in future wireless device applications. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Cassini-Huygens makes first close approach to Titan

    Science.gov (United States)

    2004-10-01

    Purple zaze hi-res Size hi-res: 88 kb Credits: NASA/JPL/Space Science Institute Purple haze around Titan This NASA/ESA/ASI Cassini-Huygens image of Titan was taken with the narrow-angle camera on 3 July 2004, from a distance of about 789 000 kilometres from Titan. The image scale is 4.7 kilometres per pixel. This image shows two thin haze layers. The outer haze layer is detached and appears to float high in the atmosphere. Because of its thinness, the high haze layer is best seen at the moon's limb. The image was taken using a spectral filter sensitive to wavelengths of ultraviolet light centred at 338 nanometres. The image has been falsely coloured, the globe of Titan retains the pale orange hue our eyes would usually see, but both the main atmospheric haze and the thin detached layer have been brightened and given a purple colour to enhance their visibility. At the time of the closest approach, which is scheduled for 18:44 CEST, the spacecraft will be travelling only 1200 kilometres above the surface of the moon, almost grazing the outer atmosphere, at a speed of six kilometres per second (21 800 kilometres per hour)! Confirmation that the fly-by was successful and that all the data were received will not take place until 03:30 CEST on 27 October. This fly-by not only allows important surface science to be performed, such as radar analysis at close quarters, but also it significantly changes the orbit of the spacecraft around Saturn. Currently Cassini-Huygens has an orbital period of four months, which will change to 48 days, thus setting the course for the next close Titan fly-by on 13 December 2004 and the Huygens probe release on 25 December. Several of the observations performed during this fly-by will provide important information for ESA’s Huygens team, who will be using the data gathered to double-check atmospheric models for entry and descent on 14 January 2005. The Huygens probe will need to perform reliably in some of the most challenging and remote

  10. Topography on Titan : New Results on Large and Small Scales

    Science.gov (United States)

    Lorenz, R. D.; Cassini Radar Team

    2011-12-01

    Although topographic coverage of Titan is and will remain sparse, some significant results have been obtained from global, regional and local measurements, via stereo, radarclinometry (shape-from-shading), autostereo (deviation from an assumed symmetric shape due to the inclined incidence), altimetry and SARtopo (monopulse) techniques. The global ellipsoidal shape (Zebker et al., 2009) provides important geophysical constraints on the interior. Hypsometry (Lorenz et al., 2011) provides insight into the balance of constructional and erosive processes and the strength of the lithosphere. Some local observations to be summarized in the talk include the measurement of mountains, the quantification of slopes that divert dunes and that drive fluid flow in river networks, as well as depth measurement of several impact craters and the assessment of candidate cryovolcanic structures. A recent new observation is a long altimetry pass T77 along the equator at the western edge of Xanadu, acquired both to constrain Titan's global shape and to understand the surface slopes and properties that may maintain the striking contrast between the dune fields of Shangri-La and the rugged and radiometrically anomalous Xanadu region. T77 also featured a SAR observation of the Ksa impact structure (discovered in SAR on T17), allowing a stereo DEM to be constructed. A feature shared by Earth and Titan is the ephemeral topography of liquids on the surface. Titan's lakes and seas likely vary in depth on geological (Myr-Gyr) and astronomical (~10 kyr) timescales : the depth of Ontario Lacus has been observed to vary on a seasonal timescale (~1 m/yr). Periodic changes of the order of 0.2-5m may occur diurnally, forced by Saturn gravitational tides. Finally, waves may be generated, at least during the windy season (which for Titan's north may be just about to begin) which can be constrained by radar and optical scattering measurements. Looking to the future, a Phase A study of the Titan Mare

  11. Dragonfly: In Situ Exploration of Titan's Organic Chemistry and Habitability

    Science.gov (United States)

    Turtle, E. P.; Barnes, J. W.; Trainer, M. G.; Lorenz, R. D.

    2017-12-01

    Titan's abundant complex carbon-rich chemistry, interior ocean, and past presence of liquid water on the surface make it an ideal destination to study prebiotic chemical processes and document the habitability of an extraterrestrial environment. Titan exploration is a high science priority due to the level of organic synthesis that it supports. Moreover, opportunities for organics to have interacted with liquid water at the surface (e.g., in impact melt sheets) increase the potential for chemical processes to progress further, providing an unparalleled opportunity to investigate prebiotic chemistry, as well as to search for signatures of potential water-based or even hydrocarbon-based life. The diversity of Titan's surface materials and environments drives the scientific need to be able to sample a variety of locations, thus mobility is key for in situ measurements. Titan's atmosphere is 4 times denser than Earth's reducing the wing/rotor area required to generate a given amount of lift, and the low gravity reduces the required magnitude of lift, making heavier-than-air mobility highly efficient. Dragonfly is a rotorcraft lander mission proposed to NASA's New Frontiers Program to take advantage of Titan's unique natural laboratory to understand how far chemistry can progress in environments that provide key ingredients for life. Measuring the compositions of materials in different environments will reveal how far organic chemistry has progressed. Surface material can be sampled into a mass spectrometer to identify the chemical components available and processes at work to produce biologically relevant compounds. Bulk elemental surface composition can be determined by a neutron-activated gamma-ray spectrometer. Meteorology measurements can characterize Titan's atmosphere and diurnal and spatial variations therein. Geologic features can be characterized via remote-sensing observations, which also provide context for samples. Seismic sensing can probe subsurface

  12. 3D hybrid simulation of the Titan's plasma environment

    Science.gov (United States)

    Lipatov, Alexander; Sittler, Edward, Jr.; Hartle, Richard

    2007-11-01

    Titan plays an important role as a simulation laboratory for multiscale kinetic plasma processes which are key processes in space and laboratory plasmas. A development of multiscale combined numerical methods allows us to use more realistic plasma models at Titan. In this report, we describe a Particle-Ion--Fluid-Ion--Fluid--Electron method of kinetic ion-neutral simulation code. This method takes into account charge-exchange and photoionization processes. The model of atmosphere of Titan was based on a paper by Sittler, Hartle, Vinas et al., [2005]. The background ions H^+, O^+ and pickup ions H2^+, CH4^+ and N2^+ are described in a kinetic approximation, where the electrons are approximated as a fluid. In this report we study the coupling between background ions and pickup ions on the multiple space scales determined by the ion gyroradiis. The first results of such a simulation of the dynamics of ions near Titan are discussed in this report and compared with recent measurements made by the Cassini Plasma Spectrometer (CAPS, [Hartle, Sittler et al., 2006]). E C Sittler Jr., R E Hartle, A F Vinas, R E Johnson, H T Smith and I Mueller-Wodarg, J. Geophys. Res., 110, A09302, 2005.R E Hartle, E C Sittler, F M Neubauer, R E Johnson, et al., Planet. Space Sci., 54, 1211, 2006.

  13. Electrical and thermal properties of lead titanate glass ceramics

    International Nuclear Information System (INIS)

    Shankar, J.; Deshpande, V.K.

    2011-01-01

    Glass samples with composition of (50-X)PbO-(25+X)TiO 2 -25B 2 O 3 (where X=0, 5, 10 and 12.5 mol%) were prepared using conventional quenching technique. The glass transition temperature, T g and crystallization temperature T c were determined from the DTA. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The glass ceramic samples were characterized by XRD, SEM and dielectric constant measurements. The XRD results revealed the formation of ferroelectric lead titanate (PT) as a major crystalline phase in the glass ceramics. The density increases and the CTE decreases for all glass ceramics with increase in X (mol%). This may be attributed to increase in PT phase. The SEM results which show rounded crystallites of lead titanate, also supports other results. Hysteresis loops observed at room temperature confirms the ferroelectric nature of glass ceramics. The optimized glass ceramic sample exhibits high dielectric constant which is of technical importance. -- Research Highlights: →Lead titanate glass ceramics prepared by conventional quenching technique. →Lead titanate is a major crystalline phase in the glass ceramics. →The ferroelectric nature of glass ceramics is confirmed by the hysteresis study. →The high value of ε observed at room temperature is quite promising in the study.

  14. Safe prescribing: a titanic challenge.

    Science.gov (United States)

    Routledge, Philip A

    2012-10-01

    The challenge to achieve safe prescribing merits the adjective 'titanic'. The organisational and human errors leading to poor prescribing (e.g. underprescribing, overprescribing, misprescribing or medication errors) have parallels in the organisational and human errors that led to the loss of the Titanic 100 years ago this year. Prescribing can be adversely affected by communication failures, critical conditions, complacency, corner cutting, callowness and a lack of courage of conviction, all of which were also factors leading to the Titanic tragedy. These issues need to be addressed by a commitment to excellence, the final component of the 'Seven C's'. Optimal prescribing is dependent upon close communication and collaborative working between highly trained health professionals, whose role is to ensure maximum clinical effectiveness, whilst also protecting their patients from avoidable harm. Since humans are prone to error, and the environments in which they work are imperfect, it is not surprising that medication errors are common, occurring more often during the prescribing stage than during dispensing or administration. A commitment to excellence in prescribing includes a continued focus on lifelong learning (including interprofessional learning) in pharmacology and therapeutics. This should be accompanied by improvements in the clinical working environment of prescribers, and the encouragement of a strong safety culture (including reporting of adverse incidents as well as suspected adverse drug reactions whenever appropriate). Finally, members of the clinical team must be prepared to challenge each other, when necessary, to ensure that prescribing combines the highest likelihood of benefit with the lowest potential for harm. © 2012 The Author. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  15. [Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

    Science.gov (United States)

    Han, Xiao-hui; Zhang, Jia-yu; Cai, Jian-qiu; Shi, Ming-guang

    2011-05-10

    To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

  16. Extrusion and properties of lead zirconate titanate piezoelectric ceramics

    DEFF Research Database (Denmark)

    Cai, S.; Millar, C.E.; Pedersen, L.

    1997-01-01

    The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

  17. Steps in growth of Nb-doped layered titanates with very high surface area suitable for water purification

    International Nuclear Information System (INIS)

    Milanović, Marija; Nikolić, Ljubica M.; Stijepović, Ivan; Kontos, Athanassios G.; Giannakopoulos, Konstantinos P.

    2014-01-01

    Nb-doped layered titanates, as highly efficient adsorbents, have been synthesized by hydrothermal reaction for variable duration and at 150 °C in a highly alkaline solution with NbCl 5 as the Nb source. The results have shown the formation of nanosheets already after 1 h of hydrothermal processing, but morphology and phase composition change as the reaction proceeds. The prepared layered titanates have been structurally investigated via scanning and transmission electron microscopy, X-ray diffraction, as well as Raman and Fourier transform infrared spectroscopies. The steps of layered titanate growth have been followed and an intermediate layered anatase phase is identified. Thus optimized growth of mesoporous titanate materials with 10% Nb atomic content present very high specific surface area of 345.3 m 2  g −1 , and perform as very efficient adsorbents for wastewater treatment applications. - Highlights: • Nb-doped layered titanates have been prepared by a hydrothermal procedure. • Introduction of Nb to precursor lowers the rate of layered titanate formation. • Steps in growth of Nb-doped layered titanates are considered. • Nb-doped layered titanates show high/fast MB adsorption from concentrated solution

  18. Diffusion barrier performance of novel Ti/TaN double layers for Cu metallization

    International Nuclear Information System (INIS)

    Zhou, Y.M.; He, M.Z.; Xie, Z.

    2014-01-01

    Highlights: • Novel Ti/TaN double layers offering good stability as a barrier against Cu metallization have been made achievable by annealing in vacuum. • The Ti/TaN double layers improved the adhesion with Cu thin films and showed good diffusion barrier between Cu and SiO 2 /Si up to the annealing condition. • The failure mechanism of Ti/TaN bi-layer is similar with the Cu/TaN/Si metallization system in which Cu atoms diffuse through the grain boundary of barrier and react with silicon to form Cu 3 Si. - Abstract: Novel Ti/TaN double layers offering good stability as a barrier against Cu metallization have been made achievable by annealing in vacuum better than 1 × 10 −3 Pa. Ti/TaN double layers were formed on SiO 2 /Si substrates by DC magnetron sputtering and then the properties of Cu/Ti/TaN/SiO 2 /Si film stacks were studied. It was found that the Ti/TaN double layers provide good diffusion barrier between Cu and SiO 2 /Si up to 750 °C for 30 min. The XRD, Auger and EDS results show that the Cu–Si compounds like Cu 3 Si were formed by Cu diffusion through Ti/TaN barrier for the 800 °C annealed samples. It seems that the improved diffusion barrier property of Cu/Ti/TaN/SiO 2 /Si stack is due to the diffusion of nitrogen along the grain boundaries in Ti layer, which would decrease the defects in Ti film and block the diffusion path for Cu diffusion with increasing annealing temperature. The failure mechanism of Ti/TaN bi-layer is similar to the Cu/TaN/Si metallization system in which Cu atoms diffuse through the grain boundary of barrier and react with silicon to form Cu 3 Si

  19. Applying quality by design (QbD) concept for fabrication of chitosan coated nanoliposomes.

    Science.gov (United States)

    Pandey, Abhijeet P; Karande, Kiran P; Sonawane, Raju O; Deshmukh, Prashant K

    2014-03-01

    In the present investigation, a quality by design (QbD) strategy was successfully applied to the fabrication of chitosan-coated nanoliposomes (CH-NLPs) encapsulating a hydrophilic drug. The effects of the processing variables on the particle size, encapsulation efficiency (%EE) and coating efficiency (%CE) of CH-NLPs (prepared using a modified ethanol injection method) were investigated. The concentrations of lipid, cholesterol, drug and chitosan; stirring speed, sonication time; organic:aqueous phase ratio; and temperature were identified as the key factors after risk analysis for conducting a screening design study. A separate study was designed to investigate the robustness of the predicted design space. The particle size, %EE and %CE of the optimized CH-NLPs were 111.3 nm, 33.4% and 35.2%, respectively. The observed responses were in accordance with the predicted response, which confirms the suitability and robustness of the design space for CH-NLP formulation. In conclusion, optimization of the selected key variables will help minimize the problems related to size, %EE and %CE that are generally encountered when scaling up processes for NLP formulations. The robustness of the design space will help minimize both intra-batch and inter-batch variations, which are quite common in the pharmaceutical industry.

  20. Studies on the effects of titanate and silane coupling agents on the performance of poly (methyl methacrylate)/barium titanate denture base nanocomposites.

    Science.gov (United States)

    Elshereksi, Nidal W; Ghazali, Mariyam J; Muchtar, Andanastuti; Azhari, Che H

    2017-01-01

    This study aimed to fabricate and characterise silanated and titanated nanobarium titanate (NBT) filled poly(methyl methacrylate) (PMMA) denture base composites and to evaluate the behaviour of a titanate coupling agent (TCA) as an alternative coupling agent to silane. The effect of filler surface modification on fracture toughness was also studied. Silanated, titanated and pure NBT at 5% were incorporated in PMMA matrix. Neat PMMA matrix served as a control. NBT was sonicated in MMA prior to mixing with the PMMA. Curing was carried out using a water bath at 75°C for 1.5h and then at 100°C for 30min. NBT was characterised via Fourier transform-infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis before and after surface modification. The porosity and fracture toughness of the PMMA nanocomposites (n=6, for each formulation and test) were also evaluated. NBT was successfully functionalised by the coupling agents. The TCA exhibited the lowest percentage of porosity (0.09%), whereas silane revealed 0.53% porosity. Statistically significant differences in fracture toughness were observed among the fracture toughness values of the tested samples (pPMMA composites. Thus, TCA seemed to be more effective than silane. Minimising the porosity level could have the potential to reduce fungus growth on denture base resin to be hygienically accepTable Such enhancements obtained with Ti-NBT could lead to promotion of the composites' longevity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Hydrothermal synthesis of highly water-dispersible anatase nanocrystals from transparent aqueous sols of titanate colloids

    International Nuclear Information System (INIS)

    Ban, Takayuki; Tanaka, Yusuke; Ohya, Yutaka

    2011-01-01

    Transparent colloidal aqueous solutions of anatase nanocrystals were hydrothermally synthesized from aqueous transparent sols with tetramethylammonium titanate colloids, the surfaces of which were modified with citric acid, by structural conversion of the titanate to anatase. This modification hindered coalescence of the titanate colloids during the hydrothermal synthesis. Although the amount of citric acid adsorbed on the colloids was reduced during hydrothermal treatment, a small amount of citric acid was adsorbed on the resulting anatase nanocrystals. Moreover, the use of the titanate colloids as a precursor was compared with the use of a citrato Ti complex, tetramethylammonium citratotitanate. The hydrothermal treatment of the transparent aqueous solutions of the Ti complex yielded opaque solutions with large anatase colloids, suggesting that the titanate colloids were useful for preparing transparent anatase colloidal solutions. Because the shape and size of resulting colloids may be dependent on the size and shape of starting colloids, the use of titanate colloids as a precursor may make it easy to control size and shape of anatase colloids.

  2. Conventional hydrothermal synthesis of titanate nanotubes: Systematic discussions on structural, optical, thermal and morphological properties

    Directory of Open Access Journals (Sweden)

    S. Muniyappan

    2017-12-01

    Full Text Available Titanate nanotubes were successfully synthesized by hydrothermal technique under acidic-base medium. The anatase and titanate phase of the starting TiO2 and tubular titanate was confirmed by powder XRD technique. The UV–vis-NIR spectroscopy was used to study the absorption nature of titanate nanotubes and the band gap was calculated as 3.3 eV. Infrared technique was employed to detect the presence of all the functional groups in the synthesized titanate nanotube material. Thermal properties of the title material were studied by TG-DTA analyses. The shrinkage of interlayer distance of TiO2 network confirms the nanotube formation. Morphology and size information about the synthesized material were carried out using FESEM and TEM analysis. Titanate nanotubes are having the maximum length of 2.24 µm and the average diameter of 169.73 nm. EDX analysis gives out the elemental composition of the as synthesized product. This report may fetch an efficient way to synthesize TiO2 nanotubes using TiO2 nanoparticles.

  3. 77 FR 59690 - Titan Resources International, Corp.; Order of Suspension of Trading

    Science.gov (United States)

    2012-09-28

    ... a lack of current and accurate information concerning the securities of Titan Resources... concerning Titan's business operations and financial condition. The Commission is of the opinion that the public interest and the protection of investors require a suspension of trading in the securities of...

  4. Laboratory investigation of nitrile ices of Titan's stratospheric clouds

    Science.gov (United States)

    Nna Mvondo, D.; Anderson, C. M.; McLain, J. L.; Samuelson, R. E.

    2017-09-01

    Titan's mid to lower stratosphere contains complex cloud systems of numerous organic ice particles comprised of both hydrocarbon and nitrile compounds. Most of these stratospheric ice clouds form as a result of vapor condensation formation processes. However, there are additional ice emission features such as dicyanoacetylene (C4N2) and the 220 cm-1 ice emission feature (the "Haystack") that are difficult to explain since there are no observed vapor emission features associated with these ices. In our laboratory, using a high-vacuum chamber coupled to a FTIR spectrometer, we are engaged in a dedicated investigation of Titan's stratospheric ices to interpret and constrain Cassini Composite InfraRed Spectrometer (CIRS) far-IR data. We will present laboratory transmittance spectra obtained for propionitrile (CH3CH2CN), cyanogen (C2N2) and hydrogen cyanide (HCN) ices, as well as various combinations of their mixtures, to better understand the cloud chemistry occurring in Titan's stratosphere.

  5. Study of barium bismuth titanate prepared by mechanochemical synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2009-01-01

    Full Text Available Barium-bismuth titanate, BaBi4Ti4O15 (BBT, a member of Aurivillius bismuth-based layer-structure perovskites, was prepared from stoichiometric amounts of barium titanate and bismuth titanate obtained via mechanochemical synthesis. Mechanochemical synthesis was performed in air atmosphere in a planetary ball mill. The reaction mechanism of BaBi4Ti4O15 and the preparation and characteristics of BBT ceramic powders were studied using XRD, Raman spectroscopy, particle analysis and SEM. The Bi-layered perovskite structure of BaBi4Ti4O15 ceramic forms at 1100 °C for 4 h without a pre-calcination step. The microstructure of BaBi4Ti4O15 exhibits plate-like grains typical for the Bi-layered structured material and spherical and polygonal grains. The Ba2+ addition leads to changes in the microstructure development, particularly in the change of the average grain size.

  6. Photometric changes on Saturn's Titan: Evidence for active cryovolcanism

    Science.gov (United States)

    Nelson, R.M.; Kamp, L.W.; Lopes, R.M.C.; Matson, D.L.; Kirk, R.L.; Hapke, B.W.; Wall, S.D.; Boryta, M.D.; Leader, F.E.; Smythe, W.D.; Mitchell, K.L.; Baines, K.H.; Jaumann, R.; Sotin, Christophe; Clark, R.N.; Cruikshank, D.P.; Drossart, P.; Lunine, J.I.; Combes, M.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Formisano, V.; Filacchione, G.; Langevin, Y.; McCord, T.B.; Mennella, V.; Nicholson, P.D.; Sicardy, B.; Irwin, P.G.J.; Pearl, J.C.

    2009-01-01

    We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7??S, 138??W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March 18, 2006. We previously reported spectrophotometric variability at another location (26??S, 78??W). Cassini Synthetic Aperture RADAR (SAR) images find that the surface morphology at both locations is consistent with surface flows possibly resulting from cryovolcanic activity (Wall et al., companion paper, this issue). The VIMS-reported time variability and SAR morphology results suggest that Titan currently exhibits intermittent surface changes consistent with present ongoing surface processes. We suggest that these processes involve material from Titan's interior being extruded or effiised and deposited on the surface, as might be expected from cryovolcanism. ?? 2009.

  7. Titan Montgolfiere Buoyancy Modulation System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Titan is ideally suited for balloon exploration due to its low gravity and dense atmosphere. Current NASA mission architectures baseline Montgolfiere balloon...

  8. Overview of the TITAN-II reversed-field pinch aqueous fusion power core design

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.P.C.; Creedon, R.L.; Grotz, S.; Cheng, E.T.; Sharafat, S.; Cooke, P.I.H.

    1988-03-01

    TITAN-II is a compact, high power density Reversed-Field Pinch fusion power reactor design based on the aqueous lithium solution fusion power core concept. The selected breeding and structural materials are LiNO/sub 3/ and 9-C low activation ferritic steel, respectively. TITAN-II is a viable alternative to the TITAN-I lithium self-cooled design for the Reversed-Field Pinch reactor to operate at a neutron wall loading of 18 MWm/sup 2/. Submerging the complete fusion power core and the primary loop in a large pool of cool water will minimize the probability of radioactivity release. Since the protection of the large pool integrity is the only requirement for the protection of the public, TITAN-II is a passive safety assurance design. 13 refs., 3 figs., 1 tab.

  9. Overview of the TITAN-II reversed-field pinch aqueous fusion power core design

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.P.C.; Creedon, R.L.; Cheng, E.T. (General Atomic Co., San Diego, CA (USA)); Grotz, S.P.; Sharafat, S.; Cooke, P.I.H. (California Univ., Los Angeles (USA). Dept. of Mechanical, Aerospace and Nuclear Engineering; California Univ., Los Angeles, CA (USA). Inst. for Plasma and Fusion Research); TITAN Research Group

    1989-04-01

    TITAN-II is a compact, high-power-density Reversed-Field Pinch fusion power reactor design based on the aqueous lithium solution fusion power core concept. The selected breeding and structural materials are LiNO/sub 3/ and 9-C low activation ferritic steel, respectively. TITAN-II is a viable alternative to the TITAN-I lithium self-cooled design for the Reversed-Field Pinch reactor to operate at a neutron wall loading of 18 MW/m/sup 2/. Submerging the complete fusion power core and the primary loop in a large pool of cool water will minimize the probability of radioactivity release. Since the protection of the large pool integrity is the only requirement for the protection of the public, TITAN-II is a level 2 of passive safety assurance design. (orig.).

  10. Remember the Titans: A Theoretical Analysis

    Directory of Open Access Journals (Sweden)

    Rameca Leary

    2013-06-01

    Full Text Available This paper addresses a pivotal time in American history, when a 1971 Supreme Court mandate required southern school districts to end segregation (Daugherity, 2011. In Alexandria, Virginia, the merger of three rival high schools yielded a racially diverse football team and coaching staff. Beforehand, blacks and whites had their own schools. Many wondered how the new T.C. Williams Titans football team would fare. This paper takes an in-depth look at the film, Remember the Titans, which is based on this story. It analyzes the film using Gordon Allport’s (1954 Intergroup Contact Theory to assess how people from different backgrounds interact within group settings. It explores how communication barriers and the absence of knowledge can lead to ignorance. A 21st century legacy is also discussed, including ideas for further research. 

  11. Remember the Titans: A Theoretical Analysis

    Directory of Open Access Journals (Sweden)

    Rameca Leary

    2013-06-01

    Full Text Available This paper addresses a pivotal time in American history, when a 1971 Supreme Court mandate required southern school districts to end segregation (Daugherity, 2011. In Alexandria, Virginia, the merger of three rival high schools yielded a racially diverse football team and coaching staff. Beforehand, blacks and whites had their own schools. Many wondered how the new T.C. Williams Titans football team would fare. This paper takes an in-depth look at the film, Remember the Titans, which is based on this story. It analyzes the film using Gordon Allport’s (1954 Intergroup Contact Theory to assess how people from different backgrounds interact within group settings. It explores how communication barriers and the absence of knowledge can lead to ignorance. A 21st century legacy is also discussed, including ideas for further research.

  12. ASSESSMENT OF STRIPPABLE COATINGS FOR DEACTIVATION AND DECOMMISSIONING

    International Nuclear Information System (INIS)

    Ebadian, M.A.

    1999-01-01

    Strippable coatings are polymer mixtures, such as water-based organic polymers, that are applied to a surface by paintbrush, roller, or spray applicator. As the polymer reacts, it attracts, absorbs, and chemically binds the contaminants; then, during the curing process, it mechanically locks the contaminants into the polymer matrix. Incorporating fiber reinforcement (such as a cotton scrim) into the coating may enhance the strength of these coatings. Once the coating dries, it can be stripped manually from the surface, In the case of auto-release coatings, the mixture cracks, flakes, and is collected by vacuuming. The surface properties of these coatings may be modified by applying a thin top coat (e.g., polyvinyl alcohol), which may provide a smoother, less permeable surface that would become less severely contaminated. In such a duplex, the thicker basis layer provides the required mechanical properties (e.g., strength and abrasion resistance), while the top layer provides protection from contamination. Once the strippable coating is removed, the loose surface contamination is removed with the coating, producing a dry, hard, non-airborne waste product. The use of strippable coatings during D and D operations has proved a viable option. These coatings can be used in the following three functions: As a protective coating, when applied to an uncontaminated surface in an area where contamination is present, so that on its removal the surface remains uncontaminated; As a decontamination agent, when applied to a contaminated surface, so that on its removal a significant decontamination of loose particulate activity is achieved; and As a fixative or tie-down coating, when applied to a contaminated surface, so that any loose contamination is tied down, thus preventing the spread of contamination during subsequent handling

  13. Synthesis and sorption properties of new synthesized rare-earth-doped sodium titanate

    International Nuclear Information System (INIS)

    Ali, I.M.

    2010-01-01

    A series of rare-earth-doped sodium titanates with the chemical formula R x H y Na 4-(x+y) TiO 4 ·nH 2 O (where R = Ce 3+ , Nd 3+ and Sm 3+ ) were grown employing solid-state fusion reaction technique. The physico-chemical investigations indicated that the new materials were self engineered into large particles enough to be used in sorption process and having crystalline structures containing localized Na + ions. Equilibrium studies revealed that an enhancement in sorption efficiency of sodium titanate after rare-earth doping. The neodymium-rich sodium titanate exhibited a better exchange affinity for Cs + compared to the other studied series. Data on the kinetics of cesium exchange fit well to pseudo-second order and intra-particle diffusion models. In a separate experiment, it was reported that the R-HNaTi series showed responsible sorption affinity toward Ce, Nd and Sm ions in their solution mixture with insignificant selectivity trend which reflects the high stability of titanate matrices. (author)

  14. SODIUM TITANATE NANOBELT AS A MICROPARTICLE TO INDUCE CLAY FLOCCULATION WITH CPAM

    Directory of Open Access Journals (Sweden)

    Wenxia Liu

    2010-07-01

    Full Text Available Sodium titanate nanobelt was synthesized by treating titanium dioxide hydrothermally in concentrated sodium hydroxide solution. The product was characterized by SEM analysis and zeta potential measurement. It served as a microparticle to constitute a microparticle retention system with cationic polyacrylamide (CPAM, while the microparticle system was employed to induce the flocculation of kaolin clay. The flocculation behavior of kaolin clay in such a system was investigated by using a photometric dispersion analyzer connected with a dynamic drainage jar. It was found that the sodium titanate nanobelt carried negative charges and had a lower zeta potential at higher pH. It gave a large synergistic flocculation effect with CPAM at a very low dosage, and showed higher flocculation effect with CPAM under neutral and weak alkaline conditions. A suitably high shear level was helpful for the re-flocculation of clay by sodium titanate nanobelt. The clay flocculation induced by CPAM/titanate nanobelt system demonstrated high shear resistance and also generated dense flocs.

  15. Radiation curable compositions useful as transfer coatings

    International Nuclear Information System (INIS)

    McCarty, W.H.; Nagy, F.A.; Guarino, J.P.

    1983-01-01

    The invention is on a method for applying a coating to a thin porous substrate and reducing absorption of the coating into the substrate by applying a radiation-curable composition to a carrying web; the radiation-curable coating composition having a crosslink density of 0.02 to about 1.0 determined by calculation of the gram moles of branch points per 100 grams of uncured coating, and a glass transition temperature of the radiation cured coating within the approximate range of -80 degrees to +100 degrees C. The carrying web being of a nature such that the coating composition, when cured, will not adhere to its surface

  16. Chemistry of the galactic cosmic ray induced ionosphere of Titan

    Science.gov (United States)

    Molina-Cuberos, G. J.; López-Moreno, J. J.; Rodrigo, R.; Lara, L. M.

    1999-09-01

    Titan's lower ionosphere (from 1 to 400 km) has been studied with a one-dimensional ion-neutral model. In this region of the atmosphere, galactic cosmic rays (GCRs) are the main ionization source. They penetrate to the deeper atmosphere and ionize the neutral constituents of Titan's atmosphere (mainly N2, CH4, Ar, H2, and CO) to produce N2+, N+, Ar+, CH4+, CH3+, CH2+, H2+, H+, and CO+. Fast reactions with the neutrals convert these ions into ions such as CH5+, C2H5+, and N2H+. Different pathways are proposed to obtain the ion and electron densities. The most abundant ions are cluster ions, like CH5+.CH4, HCO+.H2, and HCNH+.C2H4, and long chain hydrocarbon ions. In atmospheres very rich in N2, such as Titan's, ions like H4C7N+ and CH3CNH+ also represent an important contribution to the total positive ion density. Three-body reactions may play an important role in the dense atmosphere of Titan, and special attention is devoted to them. The calculated electron density in the lower atmosphere reaches a peak of ~2150 cm-3 at an altitude of 90 km.

  17. Study of the Metallurgical Aspects of Steel Micro-Alloying by Titan

    Directory of Open Access Journals (Sweden)

    Kijac, J.

    2006-01-01

    Full Text Available The metal properties upgrading applying it’s alloying with the simultaneous limitation of the impurities represents a prospective possibility of the metallurgical production further development. The interaction of the alloying substance active element with oxygen in metal and adjacent multiphase environment occurs under the actual conditions. Present paper is oriented particularly to the thermodynamic aspects of deoxygenation by titan in process of production of micro alloyed low carbon steel in two plants (oxygen converter 1-OC1 and 2-OC2 with the different effect of micro-alloy exploitation. Analysis of the effect of the metallurgical factors on the titan smelting loss in micro-alloyed steel production points at the need to master the metal preparation for the alloying and especially has got the decisive effect upon the oxidizing ability and rate of the slag phase availability. When comparing the micro-alloying matter yield among the individual production units, disclosed have been better results obtained in plant OC 2. Confirmed has been the effect of the slag amount (average amount of 7,3 t at OC 1 and 5,83 t at OC 2 and its quality during the steel tapping as one among the most significant factors affecting the alloying process and which also represent its oxidizing potential.

  18. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  19. Poster 9: Isotopic Ratios of Carbon and Oxygen in Titan's CO using ALMA

    Science.gov (United States)

    Serigano, Joseph; Nixion, Conor A.; Cordiner, Martin A.; Irwin, Patrick G. J.; Teanby, Nick A.; Charnley, Steven B.; Lindberg, Johan E.

    2016-06-01

    The advent of the Atacama Large Millimeter/Submillimeter Array (ALMA) has provided a new and powerful facility for probing the atmospheres of solar system targets at long wavelengths (84-720 GHz) where the rotational lines of small, polar molecules are prominent. In the complex atmosphere of Titan, photochemical processes dissociate and ionize molecular nitrogen and methane in the upper atmosphere, creating a complex inventory of trace hydrocarbons and nitriles. Additionally, the existence of oxygen on Titan facilitates the synthesis of molecules of potential astrobiological importance. Utilization of ground-based submillimeter observations of Titan has proven to be a powerful tool to complement results from spacecraft observations. ALMA provides the ability to probe this region in greater detail with unprecedented spectral and spatial resolution at high sensitivity, allowing for the derivation of vertical mixing profiles, molecular detections, and observations of latitudinal and seasonal variations. Recent ALMA studies of Titan have presented spectrally and spatially-resolved maps of HNC and HC3N emission (Cordiner et al. 2014), as well as the first spectroscopic detection of ethyl cyanide (C2H5CN) in Titan's atmosphere (Cordiner et al. 2015). This poster will focus on ALMA observations of carbon monoxide (CO) and its isotopologues 13CO, C18O, and C 17O in Titan's atmosphere. Molecular abundances and the vertical atmospheric temperature profile were derived by modeling the observed emission line profiles using NEMESIS, a line-by-line radiative transfer code (Irwin et al. 2008). This study reports the first spectroscopic detection of 17O in the outer solar system with C17O detected at >8σ confidence. The abundances of these molecules and isotopic ratios of 12C/13C, 16O/18O, and 16O/17O will be presented. General implications for the history of Titan from these measurements will be discussed.

  20. Properties and DEFC tests of nafion added functionalized titanate nanotubes prepared by extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Matos, B.R.; Goulart, C.A.; Isidoro, R.A.; Silva, J.S. da; Santiago, E.I.; Fonseca, F.C.; Tavares, A.C. [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2016-07-01

    Full text: Composite electrolyte membranes based on the incorporation of a second inorganic phase into ionomer matrices such as Nafion revealed to possess enhanced properties such as increased mechanical resistance and reduced permeability of solvents. It has been reported that surface functionalized titanate nanotubes (H2Ti3O7.nH2O) display a proton conductivity of ∼ 10-2 Scm-1, which is attractive for the use of such composites in direct ethanol fuel cells (DEFC). Herein, composite membranes based on the addition of sulfonic acid groups functionalized titanate nanotubes into Nafion matrix were prepared by grafting followed by extrusion. These membranes were characterized by infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), acid-base titration, proton conductivity measurements and DEFC tests. FTIR measurements confirmed both the grafting of the titanate nanotubes. BET measurements showed that the functionalized titanate nanotubes possess a high surface specific area. Acid-base titration evidenced that additional sulfonic acid groups are present in the composite membranes compared to the pristine ionomer. The conductivity measurements show that the increase in the titanate nanotube volume fraction into the ionomers has not resulted in a decrease of the proton conductivity. The results show that the addition of functionalized titanate nanotubes into Nafion polymer matrix resulted in an improvement of the electric transport properties, reduction of the fuel crossover and, consequently, a higher DEFC performance for the composites were observed with respect to the pristine Nafion. (author)

  1. Properties and DEFC tests of nafion added functionalized titanate nanotubes prepared by extrusion

    International Nuclear Information System (INIS)

    Matos, B.R.; Goulart, C.A.; Isidoro, R.A.; Silva, J.S. da; Santiago, E.I.; Fonseca, F.C.; Tavares, A.C.

    2016-01-01

    Full text: Composite electrolyte membranes based on the incorporation of a second inorganic phase into ionomer matrices such as Nafion revealed to possess enhanced properties such as increased mechanical resistance and reduced permeability of solvents. It has been reported that surface functionalized titanate nanotubes (H2Ti3O7.nH2O) display a proton conductivity of ∼ 10-2 Scm-1, which is attractive for the use of such composites in direct ethanol fuel cells (DEFC). Herein, composite membranes based on the addition of sulfonic acid groups functionalized titanate nanotubes into Nafion matrix were prepared by grafting followed by extrusion. These membranes were characterized by infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), acid-base titration, proton conductivity measurements and DEFC tests. FTIR measurements confirmed both the grafting of the titanate nanotubes. BET measurements showed that the functionalized titanate nanotubes possess a high surface specific area. Acid-base titration evidenced that additional sulfonic acid groups are present in the composite membranes compared to the pristine ionomer. The conductivity measurements show that the increase in the titanate nanotube volume fraction into the ionomers has not resulted in a decrease of the proton conductivity. The results show that the addition of functionalized titanate nanotubes into Nafion polymer matrix resulted in an improvement of the electric transport properties, reduction of the fuel crossover and, consequently, a higher DEFC performance for the composites were observed with respect to the pristine Nafion. (author)

  2. Solar Electric and Chemical Propulsion Technology Applications to a Titan Orbiter/Lander Mission

    Science.gov (United States)

    Cupples, Michael

    2007-01-01

    Several advanced propulsion technology options were assessed for a conceptual Titan Orbiter/Lander mission. For convenience of presentation, the mission was broken into two phases: interplanetary and Titan capture. The interplanetary phase of the mission was evaluated for an advanced Solar Electric Propulsion System (SEPS), while the Titan capture phase was evaluated for state-of-art chemical propulsion (NTO/Hydrazine), three advanced chemical propulsion options (LOX/Hydrazine, Fluorine/Hydrazine, high Isp mono-propellant), and advanced tank technologies. Hence, this study was referred to as a SEPS/Chemical based option. The SEPS/Chemical study results were briefly compared to a 2002 NASA study that included two general propulsion options for the same conceptual mission: an all propulsive based mission and a SEPS/Aerocapture based mission. The SEP/Chemical study assumed identical science payload as the 2002 NASA study science payload. The SEPS/Chemical study results indicated that the Titan mission was feasible for a medium launch vehicle, an interplanetary transfer time of approximately 8 years, an advanced SEPS (30 kW), and current chemical engine technology (yet with advanced tanks) for the Titan capture. The 2002 NASA study showed the feasibility of the mission based on a somewhat smaller medium launch vehicle, an interplanetary transfer time of approximately 5.9 years, an advanced SEPS (24 kW), and advanced Aerocapture based propulsion technology for the Titan capture. Further comparisons and study results were presented for the advanced chemical and advanced tank technologies.

  3. The effect of physiologic aqueous solutions on the perovskite material lead-lanthanum-zirconium titanate (PLZT)

    Science.gov (United States)

    Foster, William J.; Meen, James K.; Fox, Donald A.

    2016-01-01

    Context Perovskite compounds, including Lead-Lanthanum-Zirconium Titanate (PLZT), have wide technological application because of their unique physical properties. The use of PLZT in neuro-prosthetic systems, such as retinal implants, have been discussed in a number of publications. Since inorganic lead is a retinotoxic compound that produces retinal degeneration, the long-term stability of PLZT in aqueous biological solutions must be determined. Objective We evaluated the stability and effects of prolonged immersion of a PLZT-coated crystal in a buffered balanced salt solution. Materials and Methods Scanning Electron Microscopy and Electron Dispersive Spectroscopy (EDS) using a JEOL JSM 5410 microscope equipped with EDS were utilized to evaluate the samples before and after prolonged immersion. Results We found that lead and other constituents of PLZT leached into the surrounding aqueous medium. Discussion By comparing the unit cell of PLZT with that of CaTiO3, which has been found to react with aqueous fluids, Lead is in the same site in PLZT as Ca is in CaTiO3. It is thus reasonable that PLZT will react with aqueous solutions. Conclusion The results suggest that PLZT must either be coated with a protective layer or is not appropriate for long-term in vivo or in vitro biological applications. PMID:22697294

  4. ALMA Spectroscopy of Titan's Atmosphere: First Detections of Vinyl Cyanide and Acetonitrile Isotopologues

    Science.gov (United States)

    Cordiner, Martin; Y Palmer, Maureen; Nixon, Conor A.; Charnley, Steven B.; Mumma, Michael J.; Irwin, Pat G. J.; Teanby, Nick A.; Kisiel, Zbigniew; Serigano, Joseph

    2015-11-01

    Studies of Titan's atmospheric chemistry provide a unique opportunity to explore the origin and evolution of complex organic matter in primitive planetary atmospheres. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new telescope, well suited to the study of molecular emission from Titan's stratosphere and mesosphere. Here we present early results from our ongoing study to exploit the large volume of Titan data taken using ALMA in Early Science Mode (during the period 2012-2014). Combining data from multiple ALMA Band 6 observations, we obtained high-resolution mm-wave spectra with unprecedented sensitivity, enabling the first detection of vinyl cyanide (C2H3CN) in Titan's atmosphere. Initial estimates indicate a mesospheric abundance ratio with respect to ethyl cyanide (C2H5CN) of [C2H3CN]/[C2H5CN] = 0.31. In addition, we report the first detections on Titan of the 13C and 15N-substituted isotopologues of acetonitrile (13CH3CN and CH3C15N). Radiative transfer models and possible chemical formation pathways for these molecules will be discussed.

  5. Electrical Properties of Thin-Film Capacitors Fabricated Using High Temperature Sputtered Modified Barium Titanate

    Directory of Open Access Journals (Sweden)

    Robert Mamazza

    2012-04-01

    Full Text Available Simple thin-film capacitor stacks were fabricated from sputter-deposited doped barium titanate dielectric films with sputtered Pt and/or Ni electrodes and characterized electrically. Here, we report small signal, low frequency capacitance and parallel resistance data measured as a function of applied DC bias, polarization versus applied electric field strength and DC load/unload experiments. These capacitors exhibited significant leakage (in the range 8–210 μA/cm2 and dielectric loss. Measured breakdown strength for the sputtered doped barium titanate films was in the range 200 kV/cm −2 MV/cm. For all devices tested, we observed clear evidence for dielectric saturation at applied electric field strengths above 100 kV/cm: saturated polarization was in the range 8–15 μC/cm2. When cycled under DC conditions, the maximum energy density measured for any of the capacitors tested here was ~4.7 × 10−2 W-h/liter based on the volume of the dielectric material only. This corresponds to a specific energy of ~8 × 10−3 W-h/kg, again calculated on a dielectric-only basis. These results are compared to those reported by other authors and a simple theoretical treatment provided that quantifies the maximum energy that can be stored in these and similar devices as a function of dielectric strength and saturation polarization. Finally, a predictive model is developed to provide guidance on how to tailor the relative permittivities of high-k dielectrics in order to optimize their energy storage capacities.

  6. Effect of multi-layered bottom electrodes on the orientation of strontium-doped lead zirconate titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskaran, M. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)], E-mail: madhu.bhaskaran@gmail.com; Sriram, S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia); Mitchell, D.R.G.; Short, K.T. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, New South Wales 2234 (Australia); Holland, A.S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)

    2008-09-30

    This article discusses the results from X-ray diffraction (XRD) analysis of piezoelectric strontium-doped lead zirconate titanate (PSZT) thin films deposited on multi-layer coatings on silicon. The films were deposited by RF magnetron sputtering on a metal coated substrate. The aim was to exploit the pronounced piezoelectric effect that is theoretically expected normal to the substrate. This work highlighted the influence that the bottom electrode architecture exerts on the final crystalline orientation of the deposited thin films. A number of bottom electrode architectures were used, with the uppermost metal layer on which PSZT was deposited being gold or platinum. The XRD analysis revealed that the unit cell of the PSZT thin films deposited on gold and on platinum were deformed, relative to expected unit cell dimensions. Experimental results have been used to estimate the unit cell parameters. The XRD results were then indexed based on these unit cell parameters. The choice and the thickness of the intermediate adhesion layers influenced the relative intensity, and in some cases, the presence of perovskite peaks. In some cases, undesirable reactions between the bottom electrode layers were observed, and layer architectures to overcome these reactions are also discussed.

  7. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F.L.; Van Vliet, L.J.; Hartman Kok, P.J.A.; Vromans, H.; Frijlink, H.W.; Van der Voort Maarschalk, K.

    2008-01-01

    Purpose This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. Methods The method applies the MATLAB image processing toolbox to images of coated

  8. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F L; Van Vliet, L J; Hartman Kok, P J A; Vromans, H; Frijlink, H W; Van der Voort Maarschalk, K

    This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. The method applies the MATLAB image processing toolbox to images of coated particles taken

  9. Impurities in barium titanate posistor ceramics

    Czech Academy of Sciences Publication Activity Database

    Korniyenko, S. M.; Bykov, I. P.; Glinchuk, M. J.; Laguta, V. V.; Belous, A. G.; Jastrabík, Lubomír

    2000-01-01

    Roč. 239, - (2000), s. 1209-1218 ISSN 0015-0193 Institutional research plan: CEZ:AV0Z1010914 Keywords : barium titanate phase transition * ESR * positive temperature coefficient of resistivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.547, year: 2000

  10. Study of irradiation of flash lightning type in a Titan simulated atmosphere; Estudio de irradiaciones tipo relampago en una atmosfera simulada de Titan

    Energy Technology Data Exchange (ETDEWEB)

    Rosa C, J.G. De la

    2001-07-01

    Titan is the greatest satellite of the Saturn planet and the unique moon of the Solar System which presents a dense atmosphere constituted by nitrogen, methane and traces of hydrocarbons and nitriles. Constantly it is bombarded by different energy sources which interacting with the atmosphere cause countless of chemical reactions which have giving origin to the synthesis of organic molecules from its formation since 4.5 thousand millions of years ago. The electric activity was not detected in the satellite when the space probe Voyager I had its nearest match with Titan in November 1980, however, due to the presence of methane clouds rain and of convective activity in the troposphere of the satellite, it is thought in the possible existence of electrical activity in this. In this work it is studied the production of gaseous compounds generated by irradiations type flash lightning in the Titan simulated atmosphere constituted by nitrogen and methane. The lightning are imitated by laser induced plasma (LIP) with similar physical properties to the naturals produced in the Earth. The separation and identification of the organic compounds generated by simulated lightning s were carried out by attached methods of analysis such as the Gas chromatography, Infrared spectroscopy with Fourier transform (FTIR-S) and Mass spectroscopy (MS). The compounds which were identified are: hydrocarbons and nitriles, some of them already have been identified in Titan as well as the hydrogen cyanide (HCN), acetylene, etilene and cyanoacetylene. Moreover we studied the influence that different parameters of irradiation have in the production of organic molecules generated submitting to discharges type lightning the simulated atmosphere of Titan. It was realized an estimation of the available energy in the satellite which could be vanished as discharges type lightning. By means of a model based on conditions of thermodynamic equilibria it was calculated the temperature to which are freeze

  11. Formation of titanate nanostructures under different NaOH concentration and their application in wastewater treatment

    International Nuclear Information System (INIS)

    Huang Jiquan; Cao Yongge; Deng Zhonghua; Tong Hao

    2011-01-01

    The effects of the concentration of NaOH on the formation and transformation of various titanate nanostructures were studied. With increasing NaOH concentration, three different formation mechanisms were proposed. Nanotubes can only be obtained under moderate NaOH conditions, and should transform into nanowires with prolonged hydrothermal treatment, and their formation rate is accelerated by increasing NaOH concentration. Low concentration of NaOH results in the direct formation of nanowires, while extra high concentration of NaOH leads to the formation of amorphous nanoparticles. Adsorption and photocatalysis studies show that titanate nanowires and nanotubes might be potential adsorbents for the removal of both heavy metal ions and dyes and photocatalysts for the removal of dyes from wastewater. -- Graphical abstract: The morphologies of the titanates depend deeply on the concentration of NaOH. With increasing NaOH concentration, three different formation mechanisms were proposed. The application of these titanate nanostructures in the wastewater treatment was studied. Display Omitted Research highlights: → Effect of NaOH concentration on the structures of various titanates was reported. → Three different formation mechanisms were presented with increasing NaOH concentration. → Various titanates were used as adsorbents/photocatalysts in wastewater treatment.

  12. Titan Coupled Surface/Atmosphere Retrievals

    Science.gov (United States)

    West, R. A.; Pitman, K. M.

    2009-05-01

    Titan's thick haze obscures its surface at visible wavelengths and hinders surface photometric studies in the near-infrared. The large vertical extent of the haze produces two effects which require radiative transfer analysis beyond the capability of plane-parallel multi-scatter models. Haze aerosols extend to altitudes above 500 km and require a spherical-shell RT algorithm close to the limb or terminator. Even near nadir viewing, horizontal scattering at spatial scales less than a few hundred km requires a code capable of simulating the adjacency effect. The adjacency effect will reduce contrast more for small spatial scales than for large spatial scales, and the amount of contrast reduction depends on many factors (haze optical thickness, vertical distribution, single scattering albedo, scattering geometry, spatial scale). Titan's haze is strongly forward scattering even near 1-µm wavelength and many RT codes do a poor job. Fortunately the problem is more tractable at longer wavelengths. We show how data from the Cassini VIMS and ISS instruments can be used to understand surface contrast and atmospheric haze properties.

  13. Materials and ceramics on the base of aluminium titanate

    International Nuclear Information System (INIS)

    Gulamova, D.

    1997-01-01

    The influence of the doping and technological parameters on the thermodynamical stability of the aluminium titanate is investigated. The condition necessary to make aluminium titanate stable and established. it is shown, how the condition of the synthesis and the content of the admixture phases affect the stability of the solid solutions. The technology of obtaining the ceramics stable with respect to decay (with thermal expansion coefficient CTE = 26x10/sup -6/ grad/sup -1/ and thermoresistancy > 80 heating cycles, sigma curve equal or greater than 80 Mpa) is worked out. (author)

  14. Titan's Gravitational Field

    Science.gov (United States)

    Schubert, G.; Anderson, J. D.

    2013-12-01

    Titan's gravitational field is inferred from an analysis of archived radio Doppler data for six Cassini flybys. The analysis considers each flyby separately in contrast to the approach of lumping all the data together in a massive inversion. In this way it is possible to gain an improved understanding of the character of each flyby and its usefulness in constraining the gravitational coefficient C22 . Though our analysis is not yet complete and our final determination of C22 could differ from the result we report here by 1 or 2 sigma, we find a best-fit value of C22 equal to (13.21 × 0.17) × 10-6, significantly larger than the value of 10.0 × 10-6 obtained from an inversion of the lumped Cassini data. We also find no determination of the tidal Love number k2. The larger value of C22 implies a moment of inertia factor equal to 0.3819 × 0.0020 and a less differentiated Titan than is suggested by the smaller value. The larger value of C22 is consistent with an undifferentiated model of the satellite. While it is not possible to rule out either value of C22 , we prefer the larger value because its derivation results from a more hands on analysis of the data that extracts the weak hydrostatic signal while revealing the effects of gravity anomalies and unmodeled spacecraft accelerations on each of the six flybys.

  15. Ferroelastic domain switching fatigue in lead zirconate titanate ceramics

    International Nuclear Information System (INIS)

    Pojprapai, Soodkhet; Jones, Jacob L.; Studer, Andrew J.; Russell, Jennifer; Valanoor, Nagarajan; Hoffman, Mark

    2008-01-01

    The influence of the frequency and amplitude of cyclic mechanical loading on soft, tetragonal lead zirconate titanate (PZT) ceramics was investigated via neutron diffraction. Intensity change in the {2 0 0} reflections provided quantitative measurements of domain switching behavior, domain texture and the strain resulting from domain switching. The results are explained using a viscoelasticity model. It was found that the magnitude of applied stress affects the level of strain accumulated, while its frequency affects the time taken for the strain to reach saturation. Furthermore, markedly different behaviors are exhibited by poled and unpoled samples. For samples loaded under identical conditions, the frequency effect is more pronounced in unpoled samples and the accumulated ferroelastic strain is greater in poled samples

  16. Electronic structure of barium strontium titanate by soft-x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Y. [Mitsubishi Electric Co., Hyogo (Japan); Underwood, J.H.; Gullikson, E.M.; Perera, R.C.C. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Perovskite-type titanates, such as Strontium Titanate (STO), Barium Titanate (BTO), and Lead Titanate (PTO) have been widely studied because they show good electric and optical properties. In recent years, thin films of Barium Strontium Titanate (BST) have been paid much attention as dielectrics of dynamic random access memory (DRAM) capacitors. BST is a better insulator with a higher dielectric constant than STO and can be controlled in a paraelectric phase with an appropriate ratio of Ba/Sr composition, however, few studies have been done on the electronic structure of the material. Studies of the electronic structure of such materials can be beneficial, both for fundamental physics research and for improving technological applications. BTO is a famous ferroelectric material with a tetragonal structure, in which Ti and Ba atoms are slightly displaced from the lattice points. On the other hand, BST keeps a paraelectric phase, which means that the atoms are still at the cubic lattice points. It should be of great interest to see how this difference of the local structure around Ti atoms between BTO and BST effects the electronic structure of these two materials. In this report, the authors present the Ti L{sub 2,3} absorption spectra of STO, BTO, and BST measured with very high accuracy in energy of the absorption features.

  17. Electronic structure of barium strontium titanate by soft-x-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Uehara, Y.; Underwood, J.H.; Gullikson, E.M.; Perera, R.C.C.

    1997-01-01

    Perovskite-type titanates, such as Strontium Titanate (STO), Barium Titanate (BTO), and Lead Titanate (PTO) have been widely studied because they show good electric and optical properties. In recent years, thin films of Barium Strontium Titanate (BST) have been paid much attention as dielectrics of dynamic random access memory (DRAM) capacitors. BST is a better insulator with a higher dielectric constant than STO and can be controlled in a paraelectric phase with an appropriate ratio of Ba/Sr composition, however, few studies have been done on the electronic structure of the material. Studies of the electronic structure of such materials can be beneficial, both for fundamental physics research and for improving technological applications. BTO is a famous ferroelectric material with a tetragonal structure, in which Ti and Ba atoms are slightly displaced from the lattice points. On the other hand, BST keeps a paraelectric phase, which means that the atoms are still at the cubic lattice points. It should be of great interest to see how this difference of the local structure around Ti atoms between BTO and BST effects the electronic structure of these two materials. In this report, the authors present the Ti L 2,3 absorption spectra of STO, BTO, and BST measured with very high accuracy in energy of the absorption features

  18. Geodetic data support trapping of ethane in Titan's polar crust

    Science.gov (United States)

    Sotin, Christophe; Rambaux, Nicolas

    2016-04-01

    Titan's surface is characterized by polar depressions that strongly influence interpretations of the gravity data. This study investigates several geodynamical models that can explain these depressions. For each model, the values of the three moments of inertia are computed numerically by discretizing the interior in spherical coordinates. The study shows that a Pratt model where the polar subsurface is made of ethane clathrates can explain the polar depression, the abrupt jump in altitude at about 60 degrees latitude, and the values of the degree 2 gravity coefficients. This model, proposed by Choukroun and Sotin [1], is based on the stability of ethane clathrate hydrates relative to methane clathrate hydrates. In addition to fitting the geodetic data, it explains the absence of ethane in Titan's atmosphere although ethane is the main product of the photolysis of methane. Other geophysical models based on latitudinal variations in the tidal heating production or in the heat flux at the base of the icy crust do not provide such a good match to the gravity and topographic observations. The ethane-clathrate model predicts that all the ethane produced by photolysis of methane at the present rate during the last billion years could be stored in the polar subsurface. It is consistent with the age of Titan's surface and that of Titan's atmospheric methane inferred from geological and geochemical observations by the Cassini/Huygens mission. The present study also emphasizes the role of mass anomalies on the interpretation of the degree 2 gravity coefficients. It shows that for Titan, a slow rotator, the values of the two equatorial moments of inertia (MoI) are largely affected by the polar depressions whereas the value of polar MoI is not. Therefore, as pointed out by previous calculations [2], calculating the moment of inertia (MoI) factor from the value of J2 could lead to major errors. This is not the case for our preferred Titan's model for which the negative polar

  19. Investigations of the Structure of Titanate Nanoscrolls

    International Nuclear Information System (INIS)

    Sheppard, D.A.; Buckley, C.E.

    2005-01-01

    Full text: Nanosized materials have attracted much research lately due to their unique properties and their potential application in nanoelectronic and optoelectronic devices. Nanostructured materials have also sparked interest as possible hydrogen storage candidates. Research at Curtin University has shown titanate nanoscrolls to absorb modest amounts of hydrogen at low temperatures. Whether or not this capacity can be improved will be dependent on a thorough understanding of the structure and the way it interacts with hydrogen. Titanate nanoscrolls are made via a soft chemical process that involves ageing TiO 2 powder in a concentrated NaOH solution. The resultant nanoscrolls, once filtered and washed, are typically 8-10 nm in diameter and hundreds of nanometers long. The walls consist of 3-5 layers and the diameter of the hollow centre is typically 5 nm. A number of different structures have been assigned to nanoscrolls produced via the soft chemical process. These include anatase, H 2 Ti 3 O 7 , lepidocrocite-type structure and H 2 Ti 4 O 9 .H 2 O. Many of these structures are similar, consisting of titanate type layers, and qualitatively reproduce the X-ray diffraction data. However, preliminary data suggests that these structures are inconsistent with neutron diffraction data. Here we attempt a more quantitative analysis of the structure than those published previously using neutron and X-ray diffraction. (authors)

  20. Titan's Emergence from Winter

    Science.gov (United States)

    Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

    2011-01-01

    We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

  1. NANOCOVERING OF TITAN WITH SILICON AND MOLYBDENUM AS ACTIVATOR OF FORMATION AND REACTIONARY AGGLOMERATION OF FILTERS AND MEMBRANES

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevski

    2014-01-01

    Full Text Available The technology of production of porous powder materials with frame structure on the basis of spherical particles of titan powder by means of applying on them technological coverings (Si + Mo + C with the thickness up to 2 mm is developed. Formation of powders with covering was carried out in the mold at pressure below yield point (up to 150 MPa.

  2. Organic chemistry in Titan's atmosphere

    Science.gov (United States)

    Scattergood, T.

    1982-01-01

    Laboratory photochemical simulations and other types of chemical simulations are discussed. The chemistry of methane, which is the major known constituent of Titan's atmosphere was examined with stress on what can be learned from photochemistry and particle irradiation. The composition of dust that comprises the haze layer was determined. Isotope fractionation in planetary atmospheres is also discussed.

  3. Untangling the Chemical Evolution of Titan's Atmosphere and Surface -- From Homogeneous to Heterogeneous Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Ralf I.; Maksyutenko, Pavlo; Ennis, Courtney; Zhang, Fangtong; Gu, Xibin; Krishtal, Sergey P.; Mebel, Alexander M.; Kostko, Oleg; Ahmed, Musahid

    2010-03-16

    The arrival of the Cassini-Huygens probe at Saturn's moon Titan - the only Solar System body besides Earth and Venus with a solid surface and a thick atmosphere with a pressure of 1.4 atm at surface level - in 2004 opened up a new chapter in the history of Solar System exploration. The mission revealed Titan as a world with striking Earth-like landscapes involving hydrocarbon lakes and seas as well as sand dunes and lava-like features interspersed with craters and icy mountains of hitherto unknown chemical composition. The discovery of a dynamic atmosphere and active weather system illustrates further the similarities between Titan and Earth. The aerosol-based haze layers, which give Titan its orange-brownish color, are not only Titan's most prominent optically visible features, but also play a crucial role in determining Titan's thermal structure and chemistry. These smog-like haze layers are thought to be very similar to those that were present in Earth's atmosphere before life developed more than 3.8 billion years ago, absorbing the destructive ultraviolet radiation from the Sun, thus acting as 'prebiotic ozone' to preserve astrobiologically important molecules on Titan. Compared to Earth, Titan's low surface temperature of 94 K and the absence of liquid water preclude the evolution of biological chemistry as we know it. Exactly because of these low temperatures, Titan provides us with a unique prebiotic 'atmospheric laboratory' yielding vital clues - at the frozen stage - on the likely chemical composition of the atmosphere of the primitive Earth. However, the underlying chemical processes, which initiate the haze formation from simple molecules, have been not understood well to date.

  4. Cassini/VIMS hyperspectral observations of the HUYGENS landing site on Titan

    Science.gov (United States)

    Rodriguez, S.; Le, Mouelic S.; Sotin, Christophe; Clenet, H.; Clark, R.N.; Buratti, B.; Brown, R.H.; McCord, T.B.; Nicholson, P.D.; Baines, K.H.

    2006-01-01

    Titan is one of the primary scientific objectives of the NASA-ESA-ASI Cassini-Huygens mission. Scattering by haze particles in Titan's atmosphere and numerous methane absorptions dramatically veil Titan's surface in the visible range, though it can be studied more easily in some narrow infrared windows. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini spacecraft successfully imaged its surface in the atmospheric windows, taking hyperspectral images in the range 0.4-5.2 ??m. On 26 October (TA flyby) and 13 December 2004 (TB flyby), the Cassini-Huygens mission flew over Titan at an altitude lower than 1200 km at closest approach. We report here on the analysis of VIMS images of the Huygens landing site acquired at TA and TB, with a spatial resolution ranging from 16 to14.4 km/pixel. The pure atmospheric backscattering component is corrected by using both an empirical method and a first-order theoretical model. Both approaches provide consistent results. After the removal of scattering, ratio images reveal subtle surface heterogeneities. A particularly contrasted structure appears in ratio images involving the 1.59 and 2.03 ??m images north of the Huygens landing site. Although pure water ice cannot be the only component exposed at Titan's surface, this area is consistent with a local enrichment in exposed water ice and seems to be consistent with DISR/Huygens images and spectra interpretations. The images show also a morphological structure that can be interpreted as a 150 km diameter impact crater with a central peak. ?? 2006 Elsevier Ltd. All rights reserved.

  5. Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

    Directory of Open Access Journals (Sweden)

    B. Kazeminejad

    2005-06-01

    Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

  6. Reorientation Timescales and Pattern Dynamics for Titan's Dunes: Does the Tail Wag the Dog or the Dragon?

    Science.gov (United States)

    Hayes, A. G.; Ewing, R. C.; Cassini Radar Science Team, T.

    2011-12-01

    Fields of bedform patterns persist across many orders of magnitude, from cm-scale sub-aqueous current ripples to km-scale aeolian dunes, and form with surprisingly little difference in expression despite a range of formative environments. Because of the remarkable similarity between and among patterns, extracting information about climate and environment from these patterns is a challenge. For example, crest orientation is not diagnostic of a particular flow regime; similar patterns form under many different flow configurations. On Titan, these challenges have played out with many attempts to reconcile dune-field patterns with modeled and expected wind regimes. We propose that thinking about the change in dune orientation, rather than the orientation itself, can provide new insights on the long-term stability of the dune-field patterns and the formative wind regime. In this work, we apply the re-orientation model presented by Werner and Kocurek [Geology, 1997] to the equatorial dune fields of Titan. We measure variations in pattern parameters (crest spacing, crest length and defect density, which is the number of defect pairs per total crest length) both within and between Titan's dune fields to describe pattern maturity and identify areas where changes in dune orientation are likely to occur (or may already be occurring). Measured defect densities are similar to Earth's largest linear dune fields, such as the Namib Sand Sea and the Simpson Desert. We use measured defect densities in the Werner and Kocurek model to estimate crestline reorientation rates. We find reorientation timescales varying from ten to a hundred thousand times the average migration timescale (time to migrate a bedform one meter, ~1 Titan year according to Tokano (Aeolian Research, 2010)). Well organized patterns have the longest reorientation time scales (~10^5 migration timescales), while the topographically or spatially isolated patches of dunes show the shortest reorientation times (~10

  7. Characterization and formation of hydroxyapatite on Ti6Al4V coated by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Durdu, Salih; Deniz, Ömer Faruk; Kutbay, Işıl; Usta, Metin

    2013-01-01

    Highlights: ► Ti6Al4V alloys were coated by PEO in calcium acetate and β-calcium glycerophosphate. ► Hydroxyapatite and calcium apatite based phases were directly formed on Ti6Al4V. ► Hydroxyapatite coatings were characterized systematically for different times. ► After 5 min, hydroxyapatite and calcium based phases begin to form on the coating. ► HAp on the coating is amorphous due to the rapid solidification during PEO. - Abstract: In this study, Ti6Al4V alloy was coated in the solution consisting of calcium acetate (CA) and β-calcium glycerophosphate (β-Ca-GP) by plasma electrolytic oxidation (PEO) to produce hydroxyapatite and calcium apatite-based composite used as of bioactive and biocompatible materials in biomedical applications. The phase structures, surface morphologies, functional groups of molecules, chemical compositions of the surfaces and the binding energies of atoms in the coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. Anatase, rutile, calcium oxide, titanium phosphide, whitlockite, tri-calcium phosphate (TCP), perovskite calcium titanate and hydroxyapatite phases on the coating were detected by XRD analysis. The surface of coatings produced by PEO method has a porous structure. The amount of amorphous hydroxyapatite is the highest value for the coating produced at 5 min in XPS and ATR-FTIR results, whereas the amount of crystalline hydroxyapatite has the highest value for coating produced at 120 min in XRD results.

  8. Anti fouling effect of two saturated copper coatings applied on carbon steel structures

    International Nuclear Information System (INIS)

    Guiamet, P. S.; Gomez de Saravia, S. G.

    2008-01-01

    Biofouling is the colonization of man-made substrata by sessile organisms. The aim of this paper is to evaluate the performance of two anti fouling saturated copper coating. Bioassays were carried out at a harbor in Argentine (38 degree centigrade 02' S-57 degree centigrade 32'W). during six months, one series of pipes and panels were removed monthly to estimate the recruitment of macro and micro fouling species and immediately replaced by clean ones. Another series was removed from the beginning of exposure to monitor the development of the established community (accumulative pipes and panels along six months). Data obtained from control (without a saturated copper coating) and saturated-copper coated pipes and panels were compared in order to estimate performance of the coating. One of two saturated copper coating demonstrated a good effect anti fouling. (Author) 25 refs

  9. Titan's Primordial Soup: Formation of Amino Acids via Low-Temperature Hydrolysis of Tholins

    Science.gov (United States)

    Neish, Catherine D.; Somogyi, Árpád; Smith, Mark A.

    2010-04-01

    Titan organic haze analogues, or "tholins," produce biomolecules when hydrolyzed at low temperature over long timescales. By using a combination of high-resolution mass spectroscopy and tandem mass spectrometry fragmentation techniques, four amino acids were identified in a tholin sample that had been hydrolyzed in a 13 wt % ammonia-water solution at 253 ± 1 K and 293 ± 1 K for 1 year. These four species have been assigned as the amino acids asparagine, aspartic acid, glutamine, and glutamic acid. This represents the first detection of biologically relevant molecules created under conditions thought to be similar to those found in impact melt pools and cryolavas on Titan, which are at a stage of chemical evolution not unlike the "primordial soup" of the early Earth. Future missions to Titan should therefore carry instrumentation capable of, but certainly not limited to, detecting amino acids and other prebiotic molecules on Titan's surface.

  10. Chemistry in Titan

    Science.gov (United States)

    Plessis, S.; Carrasco, N.; Pernot, P.

    2009-04-01

    Modelling the chemical composition of Titan's ionosphere is a very challenging issue. Latest works perform either inversion of CASSINI's INMS mass spectra (neutral[1] or ion[2]), or design coupled ion-neutral chemistry models[3]. Coupling ionic and neutral chemistry has been reported to be an essential feature of accurate modelling[3]. Electron Dissociative Recombination (EDR), where free electrons recombine with positive ions to produce neutral species, is a key component of ion-neutral coupling. There is a major difficulty in EDR modelling: for heavy ions, the distribution of neutral products is incompletely characterized by experiments. For instance, for some hydrocarbon ions only the carbon repartition is measured, leaving the hydrogen repartition and thus the exact neutral species identity unknown[4]. This precludes reliable deterministic modelling of this process and of ion-neutral coupling. We propose a novel stochastic description of the EDR chemical reactions which enables efficient representation and simulation of the partial experimental knowledge. The description of products distribution in multi-pathways reactions is based on branching ratios, which should sum to unity. The keystone of our approach is the design of a probability density function accounting for all available informations and physical constrains. This is done by Dirichlet modelling which enables one to sample random variables whose sum is constant[5]. The specifics of EDR partial uncertainty call for a hierarchiral Dirichlet representation, which generalizes our previous work[5]. We present results on the importance of ion-neutral coupling based on our stochastic model. C repartition H repartition (measured) (unknown ) → C4H2 + 3H2 + H .. -→ C4 . → C4H2 + 7H → C3H8. + CH C4H+9 + e- -→ C3 + C .. → C3H3 + CH2 + 2H2 → C2H6 + C2H2 + H .. -→ C2 + C2 . → 2C2H2 + 2H2 + H (1) References [1] J. Cui, R.V. Yelle, V. Vuitton, J.H. Waite Jr., W.T. Kasprzak

  11. Titan from Cassini-Huygens

    CERN Document Server

    Brown, Robert H; Waite, J. Hunter

    2010-01-01

    This book reviews our current knowledge of Saturn's largest moon Titan featuring the latest results obtained by the Cassini-Huygens mission. A global author team addresses Titan’s origin and evolution, internal structure, surface geology, the atmosphere and ionosphere as well as magnetospheric interactions. The book closes with an outlook beyond the Cassini-Huygens mission. Colorfully illustrated, this book will serve as a reference to researchers as well as an introduction for students.

  12. Hydroxyapatite coatings for biomedical applications

    CERN Document Server

    Zhang, Sam

    2013-01-01

    Hydroxyapatite coatings are of great importance in the biological and biomedical coatings fields, especially in the current era of nanotechnology and bioapplications. With a bonelike structure that promotes osseointegration, hydroxyapatite coating can be applied to otherwise bioinactive implants to make their surface bioactive, thus achieving faster healing and recovery. In addition to applications in orthopedic and dental implants, this coating can also be used in drug delivery. Hydroxyapatite Coatings for Biomedical Applications explores developments in the processing and property characteri

  13. Large Abundances of Polycyclic Aromatic Hydrocarbons in Titan's Upper Atmosphere

    Science.gov (United States)

    Lopez-Puertas, M.; Dinelli, B. M.; Adriani, A.; Funke, B.; Garcia-Comas, M.; Moriconi, M. L.; D'Aversa, E.; Boersma, C.; Allamandola, L. J.

    2013-01-01

    In this paper, we analyze the strong unidentified emission near 3.28 micron in Titan's upper daytime atmosphere recently discovered by Dinelli et al.We have studied it by using the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbons (PAHs), after absorbing UV solar radiation, are able to emit strongly near 3.3 micron. By using current models for the redistribution of the absorbed UV energy, we have explained the observed spectral feature and have derived the vertical distribution of PAH abundances in Titan's upper atmosphere. PAHs have been found to be present in large concentrations, about (2-3) × 10(exp 4) particles / cubic cm. The identified PAHs have 9-96 carbons, with a concentration-weighted average of 34 carbons. The mean mass is approx 430 u; the mean area is about 0.53 sq. nm; they are formed by 10-11 rings on average, and about one-third of them contain nitrogen atoms. Recently, benzene together with light aromatic species as well as small concentrations of heavy positive and negative ions have been detected in Titan's upper atmosphere. We suggest that the large concentrations of PAHs found here are the neutral counterpart of those positive and negative ions, which hence supports the theory that the origin of Titan main haze layer is located in the upper atmosphere.

  14. Pressure-induced absorption coefficients for radiative transfer calculations in Titan's atmosphere

    Science.gov (United States)

    Courtin, Regis

    1988-01-01

    The semiempirical theory of Birnbaum and Cohen (1976) is used to calculate the FIR pressure-induced absorption (PIA) spectra of N2, CH4, N2 + Ar, N2 + CH4, and N2 + H2 under conditions like those in the Titan troposphere. The results are presented graphically and compared with published data from laboratory measurements of PIA in the same gases and mixtures (Dagg et al., 1986; Dore et al., 1986). Good agreement is obtained, with only a slight underestimation of PIA at 300-400/cm in the case of CH4. The absorption coefficients are presented in tables, and it is suggested that the present findings are of value for evaluating the effects of tropospheric clouds on the Titan FIR spectrum and studying the greenhouse effect near the Titan surface.

  15. Formation of barium strontium titanate powder by solid state reaction using different calcination temperatures

    International Nuclear Information System (INIS)

    Teoh Wah Tzu; Ahmad Fauzi Mohd Noor; Zainal Arifin Ahmad

    2002-01-01

    The unique electrical properties of large permittivity in Barium Strontium Titanate have been widely used to make capacitors; it can be produced by solid state reaction. In this study, the mixture of Barium Carbonate, Strontium Carbonate and Titanium Dioxide was calcined at 500 degree C, 1000 degree C, 1100 degree C , 1150 degree C, 1200 degree C, 1250 degree C and 1300 degree C. The results of the phases change in each stage were investigated via X ay Diffraction. The results show that the formation of Barium Strontium Titanate started at 1100 degree C with the presence of other phases. The mixture is fully reacted to form Barium Strontium Titanate at 1150 degree C. Only Barium Strontium Titanate was formed as the calcination temperature was set higher. (Author)

  16. Characteristics of (Ti,Ta)N thin films prepared by using pulsed high energy density plasma

    Energy Technology Data Exchange (ETDEWEB)

    Feng Wenran [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Chen Guangliang [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Li Li [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Lv Guohua [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Zhang Xianhui [College of Science, Changchun University of Science and Technology, Changchun 130022, Jilin Province (China); Niu Erwu [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Liu Chizi [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Yang Size [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2007-07-21

    (Ti,Ta)N films were prepared by pulsed high energy density plasma (PHEDP) from a coaxial gun in N{sub 2} gas. The coaxial gun is composed of a tantalum inner electrode and a titanium outer one. Material characteristics of the (Ti,Ta)N film were investigated by x-ray photoelectron spectroscopy and x-ray diffraction. The microstructure of the film was observed by a scanning electron microscope. The elemental composition and the interface of the film/substrate were analysed using Auger electron spectrometry. Our results suggest that the binary metal nitride film (Ti,Ta)N, can be prepared by PHEDP. It also shows that dense nanocrystalline (Ti,Ta)N film can be achieved.

  17. Chemical compatibility study of lithium titanate with Indian reduced activation ferritic martensitic steel

    International Nuclear Information System (INIS)

    Sonak, Sagar; Jain, Uttam; Haldar, Rumu; Kumar, Sanjay

    2015-01-01

    Highlights: • Chemical compatibility between Li_2TiO_3 and Indian RAFM steel has been studied at ITER operating temperature. • The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. • The layer grew in a parabolic manner as a function of heating time. • Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer. - Abstract: Chemical compatibility between lithium titanate and Indian reduced activation ferritic-martensitic steel (In-RAFMS) was studied for the first time under ITER operating temperature. Lithium titanate required for the study was synthesized in-house. Coupons of In-RAFMS were packed inside lithium titanate powder and heated at 550 °C up to 900 h under inert argon atmosphere. The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. The layer grew in a parabolic manner as a function of heating time. Microstructural and phase evolution of this oxide layer was studied using XRD, SEM and EPMA. Iron and chromium enriched zones were found within the oxide layer. Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer.

  18. Titan's Surface Temperatures Maps from Cassini - CIRS Observations

    Science.gov (United States)

    Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Samuelson, R. E.; Irwin, P. G. J.; Flasar, F. M.

    2009-09-01

    The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 μm (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the instrument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature profile by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). In future, application of our methodology over wide areas should greatly increase the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp. 1136-1150, 2008. Rodgers, C. D.: "Inverse Methods For Atmospheric Sounding: Theory and Practice". World Scientific, Singapore, 2000. Jennings, D.E., et al.: "Titan's Surface Brightness Temperatures." Ap. J. L., Vol. 691, pp. L103-L

  19. Photoreactivity of condensed species in Titan lower atmosphere

    Science.gov (United States)

    Fleury, Benjamin; Gudipati, Murthy; Couturier-Tamburelli, Isabelle; Carrasco, Nathalie

    2017-10-01

    Photochemical processes initiated in the thermosphere of Titan at about 1000 km by the dissociation and the ionization of N2 and CH4 by the VUV solar photons [1] lead to the formation of a number of hydrocarbons and nitriles species. Some of these species can condense in the troposphere and the lower stratosphere of Titan ( 300 nm) can reach these lower atmospheric layers [4], ongoing possible further solid-state chemistry as demonstrated experimentally [5]. We will present here an experimental study simulating the reactivity of ices in the atmosphere of Titan and will discuss the photoreactivity occurring in the lower atmospheric layers of Titan despite the absorption of the most energetic photons.AcknowledgmentsThis work is supported by NASA Solar System Workings grant " Photochemistry in Titan’s Lower Atmosphere". The research work has been carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. NC acknowledges the European Research Council for their financial support (ERC Starting Grant PRIMCHEM, grant agreement n°636829).References[1] Waite, J. H., et al., The process of Tholin formation in Titan’s upper atmosphere, (2007), Science 316, 870-875.[2] Barth, E. L., Modeling survey of ices in Titan’s stratosphere, (2017), Planetary and Space Science 137, 20-31.[3] Fulchignoni, M., et al., In situ measurements of the physical characteristics of Titan’s environment, (2005), Nature 438, 785-791.[4] Tomasko, M. G., et al., Rain, winds and haze during the Huygens probe’s descent to Titan’s surface, (2005), Nature 438, 765-778.[5] Gudipati, M. S., et al., Photochemical activity of Titan’s low-altitude condensed haze, (2013), Nature Communications, 4: p1648.

  20. ALMA OBSERVATIONS OF HCN AND ITS ISOTOPOLOGUES ON TITAN

    Energy Technology Data Exchange (ETDEWEB)

    Molter, Edward M.; Nixon, C. A.; Cordiner, M. A.; Charnley, S. B.; Lindberg, J. E. [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Serigano, J. [Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218 (United States); Irwin, P. G. J. [Atmospheric, Oceanic, and Planetary Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom); Teanby, N. A., E-mail: edward.m.molter@nasa.gov [School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS8 1RJ (United Kingdom)

    2016-08-01

    We present sub-millimeter spectra of HCN isotopologues on Titan, derived from publicly available ALMA flux calibration observations of Titan taken in early 2014. We report the detection of a new HCN isotopologue on Titan, H{sup 13}C{sup 15}N, and confirm an earlier report of detection of DCN. We model high signal-to-noise observations of HCN, H{sup 13}CN, HC{sup 15}N, DCN, and H{sup 13}C{sup 15}N to derive abundances and infer the following isotopic ratios: {sup 12}C/{sup 13}C = 89.8 ± 2.8, {sup 14}N/{sup 15}N = 72.3 ± 2.2, D/H = (2.5 ± 0.2) × 10{sup −4}, and HCN/H{sup 13}C{sup 15}N = 5800 ± 270 (1 σ errors). The carbon and nitrogen ratios are consistent with and improve on the precision of previous results, confirming a factor of ∼2.3 elevation in {sup 14}N/{sup 15}N in HCN compared to N{sub 2} and a lack of fractionation in {sup 12}C/{sup 13}C from the protosolar value. This is the first published measurement of D/H in a nitrile species on Titan, and we find evidence for a factor of ∼2 deuterium enrichment in hydrogen cyanide compared to methane. The isotopic ratios we derive may be used as constraints for future models to better understand the fractionation processes occurring in Titan’s atmosphere.

  1. Rapidly curable electrically conductive clear coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Mark P.; Anderson, Lawrence G.; Post, Gordon L.

    2018-01-16

    Rapidly curable electrically conductive clear coatings are applied to substrates. The electrically conductive clear coating includes to clear layer having a resinous binder with ultrafine non-stoichiometric tungsten oxide particles dispersed therein. The clear coating may be rapidly cured by subjecting the coating to infrared radiation that heats the tungsten oxide particles and surrounding resinous binder. Localized heating increases the temperature of the coating to thereby thermally cure the coating, while avoiding unwanted heating of the underlying substrate.

  2. Duplex aluminized coatings

    Science.gov (United States)

    Gedwill, M. A.; Grisaffe, S. J. (Inventor)

    1975-01-01

    The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

  3. Preparation of poly(methyl methacrylate) grafted titanate nanotubes by in situ atom transfer radical polymerization

    International Nuclear Information System (INIS)

    Gao Yuan; Zhou Yongfeng; Yan Deyue; Gao Xueping

    2008-01-01

    This paper reports the successful preparation of core-shell hybrid nanocomposites by a 'grafting from' approach based on in situ atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) from titanate nanotubes (TNTs). Transmission electron microscope (TEM) images of the products provide direct evidence for the formation of a core-shell structure, possessing a hard core of TNTs and a soft shell of poly-MMA (PMMA). Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance ( 1 H NMR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) were used to determine the chemical structure, morphology, and the grafted PMMA quantities of the resulting products. The grafted PMMA content was well controlled and increased with increasing monomer/initiator ratio. Further copolymerization of hydroxyethyl methacrylate (HEMA) with PMMA-coated TNTs as initiators was realized, illustrating the 'living' characteristics of the ATRP method used in this paper.

  4. Method for Qualification of Coatings Applied to Wet Surfaces

    Science.gov (United States)

    2009-12-16

    The field application of a pipeline repair or rehabilitation coating usually cannot wait until ambient conditions become optimal. In a humid environment, water can condense on the pipe surface because the pipe surface is usually cooler than the ambie...

  5. The evolution of Titan's high-altitude aerosols under ultraviolet irradiation

    Science.gov (United States)

    Carrasco, Nathalie; Tigrine, Sarah; Gavilan, Lisseth; Nahon, Laurent; Gudipati, Murthy S.

    2018-04-01

    The Cassini-Huygens space mission revealed that Titan's thick brownish haze is initiated high in the atmosphere at an altitude of about 1,000 km, before a slow transportation down to the surface. Close to the surface, at altitudes below 130 km, the Huygens probe provided information on the chemical composition of the haze. So far, we have not had insights into the possible photochemical evolution of the aerosols making up the haze during their descent. Here, we address this atmospheric aerosol aging process, simulating in the laboratory how solar vacuum ultraviolet irradiation affects the aerosol optical properties as probed by infrared spectroscopy. An important evolution was found that could explain the apparent contradiction between the nitrogen-poor infrared spectroscopic signature observed by Cassini below 600 km of altitude in Titan's atmosphere and a high nitrogen content as measured by the aerosol collector and pyrolyser of the Huygens probe at the surface of Titan.

  6. Radioisotope Stirling Engine Powered Airship for Atmospheric and Surface Exploration of Titan

    Science.gov (United States)

    Colozza, Anthony J.; Cataldo, Robert L.

    2014-01-01

    The feasibility of an advanced Stirling radioisotope generator (ASRG) powered airship for the near surface exploration of Titan was evaluated. The analysis did not consider the complete mission only the operation of the airship within the atmosphere of Titan. The baseline airship utilized two ASRG systems with a total of four general-purpose heat source (GPHS) blocks. Hydrogen gas was used to provide lift. The ASRG systems, airship electronics and controls and the science payload were contained in a payload enclosure. This enclosure was separated into two sections, one for the ASRG systems and the other for the electronics and payload. Each section operated at atmospheric pressure but at different temperatures. The propulsion system consisted of an electric motor driving a propeller. An analysis was set up to size the airship that could operate near the surface of Titan based on the available power from the ASRGs. The atmospheric conditions on Titan were modeled and used in the analysis. The analysis was an iterative process between sizing the airship to carry a specified payload and the power required to operate the electronics, payload and cooling system as well as provide power to the propulsion system to overcome the drag on the airship. A baseline configuration was determined that could meet the power requirements and operate near the Titan surface. From this baseline design additional trades were made to see how other factors affected the design such as the flight altitude and payload mass and volume.

  7. Microwave-hydrothermal synthesis of barium strontium titanate nanoparticles

    International Nuclear Information System (INIS)

    Simoes, A.Z.; Moura, F.; Onofre, T.B.; Ramirez, M.A.; Varela, J.A.; Longo, E.

    2010-01-01

    Research highlights: → Barium strontium titanate nanoparticles were obtained by the Hydrothemal microwave technique (HTMW) → This is a genuine technique to obtain nanoparticles at low temperature and short times → Barium strontium titanate free of carbonates with tetragonal structure was grown at 130 o C. - Abstract: Hydrothermal-microwave method (HTMW) was used to synthesize crystalline barium strontium titanate (Ba 0.8 Sr 0.2 TiO 3 ) nanoparticles (BST) in the temperature range of 100-130 o C. The crystallization of BST with tetragonal structure was reached at all the synthesis temperatures along with the formation of BaCO 3 as a minor impurity at lower syntheses temperatures. Typical FT-IR spectra for tetragonal (BST) nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH- groups, commonly found in materials obtained by HTMW process. FE/SEM revealed that lower syntheses temperatures led to a morphology that consisted of uniform grains while higher syntheses temperature consisted of big grains isolated and embedded in a matrix of small grains. TEM has shown BST nanoparticles with diameters between 40 and 80 nm. These results show that the HTMW synthesis route is rapid, cost effective, and could serve as an alternative to obtain BST nanoparticles.

  8. Develop techniques for ion implantation of PLZT [lead-lanthanum-zirconate-titanate] for adaptive optics

    International Nuclear Information System (INIS)

    Batishko, C.R.; Brimhall, J.L.; Pawlewicz, W.T.; Stahl, K.A.; Toburen, L.H.

    1987-09-01

    Research was conducted at Pacific Northwest Laboratory to develop high photosensitivity adaptive optical elements utilizing ion implanted lanthanum-doped lead-zirconate-titanate (PLZT). One centimeter square samples were prepared by implanting ferroelectric and anti-ferroelectric PLZT with a variety of species or combinations of species. These included Ne, O, Ni, Ne/Cr, Ne/Al, Ne/Ni, Ne/O, and Ni/O, at a variety of energies and fluences. An indium-tin oxide (ITO) electrode coating was designed to give a balance of high conductivity and optical transmission at near uv to near ir wavelengths. Samples were characterized for photosensitivity; implanted layer thickness, index of refraction, and density; electrode (ITO) conductivity; and in some cases, residual stress curvature. Thin film anti-ferroelectric PLZT was deposited in a preliminary experiment. The structure was amorphous with x-ray diffraction showing the beginnings of a structure at substrate temperatures of approximately 550 0 C. This report summarizes the research and provides a sampling of the data taken during the report period

  9. Orientation of rapid thermally annealed lead zirconate titanate thin films on (111) Pt substrate

    International Nuclear Information System (INIS)

    Brooks, K.G.; Reaney, I.M.; Klissurska, R.; Huang, Y.; Bursill, L.A.; Setter, N.

    1994-01-01

    The nucleation, growth and orientation of lead zirconate titanate thin films prepared from organometallic precursor solutions by spin coating on (111) oriented platinum substrates and crystallized by rapid thermal annealing was investigated. The effects of pyrolysis temperature, post-pyrolysis thermal treatments, excess lead addition, and Nb dopant substitution are reported. The use of post pyrolysis oxygen anneals at temperatures in the regime of 350-450 deg C was found to strongly effect the kinetics of subsequent amorphous-pyrochlore perovskite crystallization by rapid thermal annealing. It has also allowed films of reproducible microstructure and textures (both (100) and (111)) to be prepared by rapid thermal annealing. It is suggested that such anneals and pyrolysis temperature affect the oxygen concentration/average Pb valence in the amorphous films prior to annealing. The changes in Pb valence state then affect the stability of the transient pyrochlore phase and thus the kinetics of perovskite crystallization. Nb dopant was also found to influence the crystallization kinetics. 28 refs., 18 figs

  10. Effects of PEG4000 template on sol-gel synthesis of porous cerium titanate photocatalyst

    Science.gov (United States)

    Zhang, Wenjie; Tao, Yingjie; Li, Chuanguo

    2018-04-01

    Porous cerium titanate was synthesized by sol-gel method, using polyethylene glycol (PEG4000) as template agent. Brannerite structured CeTi2O6 in monoclinic system is the major substance formed in the materials. Formation of CeO2 and rutile TiO2 depends on the amount of PEG4000. The addition of PEG4000 leads to production of fine particles in the samples, but it does not apparently affect the band gap energy. Pore volume of the cerium titanate sample continuously increases with rising PEG4000 amount. The sample obtained using 3.5 g PEG4000 has BET surface area of 16.2 m2/g and pore volume of 0.0232 cm3/g. The addition of PEG4000 can obviously promote photocatalytic activity of cerium titanate, which can be proven by both enhanced production of hydroxyl radical and ofloxacin degradation efficiency. As much as 95.2% of the initial ofloxacin molecules are removed from the solution after 50 min of photocatalytic degradation on the cerium titanate obtained using 3.5 g PEG4000, while only 48.4% ofloxacin is removed on cerium titanate obtained without PEG4000.

  11. Investigating the Chemical Pathways to PAH- and PANH-Based Aerosols in Titan's Atmospheric chemistry

    Science.gov (United States)

    Sciamma-O'Brien, Ella Marion; Contreras, Cesar; Ricketts, Claire Louise; Salama, Farid

    2011-01-01

    A complex organic chemistry between Titan's two main constituents, N2 and CH4, leads to the production of more complex molecules and subsequently to solid organic aerosols. These aerosols are at the origin of the haze layers giving Titan its characteristic orange color. In situ measurements by the Ion Neutral Mass Spectrometer (INMS) and Cassini Plasma Spectrometer (CAPS) instruments onboard Cassini have revealed the presence of large amounts of neutral, positively and negatively charged heavy molecules in the ionosphere of Titan. In particular, benzene (C6H6) and toluene (C6H5CH3), which are critical precursors of polycyclic aromatic hydrocarbon (PAH) compounds, have been detected, suggesting that PAHs might play a role in the production of Titan s aerosols. Moreover, results from numerical models as well as laboratory simulations of Titan s atmospheric chemistry are also suggesting chemical pathways that link the simple precursor molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN ...) to benzene, and to PAHs and nitrogen-containing PAHs (or PANHs) as precursors to the production of solid aerosols.

  12. The Titan Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal; Jinschek, Jörg R.

    2009-01-01

    University of Denmark (DTU) provides a unique combination of techniques for studying materials of interest to the catalytic as well as the electronics and other communities [5]. DTU’s ETEM is based on the FEI Titan platform providing ultrahigh microscope stability pushing the imaging resolution into the sub...

  13. [Effect of sintering gold paste coating on the bonding strength of pure titanium and three low-fusing porcelains].

    Science.gov (United States)

    Zhang, Ya-li; Luo, Xiao-ping; Zhou, Li

    2012-05-01

    To study the effect of sintering gold paste coating of pure titanium on the adhesion of three porcelains following the protocol ISO 9693, and to investigate the titanium-porcelains interfaces. Sixty machined pure titanium samples were prepared in a rectangular shape according to ISO 9693 and divided equally into six groups. Half of the strips were coated with gold paste (Deckgold) and sintered. Three ultra-low-fusing dental porcelains (I: Initial Ti, S: Super porcelain Ti-22, T: TitanKeramik) were fused onto the titanium surfaces. A thin layer of bonding agent was only applied on the surfaces of uncoated gold specimens. The interface of the porcelain and titanium was observed with a field emission scanning electron microscope (FE-SEM) after metallographic preparation and sputtered with a very thin carbon layer of the embedded titanium-porcelain interface. After three-point bending test was performed, optical stereomicroscope was used to characterize the titanium-porcelains adhesion and determine the mode of failure. FE-SEM illustrated intermetallic compounds of Au-Ti formed with some visible microcracks in the gold layer and the interface of gold layer and ceramic. All the uncoated gold titanium-porcelain system showed predominately adhesive fracture at the titanium oxidation, whereas the failure modes in all gold coated systems were cohesive and adhesive, mainly cohesive. The three-point-bending test showed that the bonding strength of GS and GI groups [(37.08 ± 4.32) and (36.20 ± 2.40) MPa] were higher than those in uncoated groups [(31.56 ± 3.74) and (30.88 ± 2.60) MPa, P 0.05). The gold paste intermediate coatings can improve bond strengths of Super porcelain Ti-22 system and Initial Ti system, which have potential applications in clinical fields.

  14. Electronic properties of lithium titanate ceramic

    International Nuclear Information System (INIS)

    Padilla-Campos, Luis; Buljan, Antonio

    2001-01-01

    Research on tritium breeder material is fundamental to the development of deuterium-tritium type fusion reactors for producing clean, non contaminating, electrical energy, since only energy and helium, a harmless gas, are produced from the fusion reaction. Lithium titanate ceramic is one of the possible candidates for the tritium breeder material. This last material is thought to form part of the first wall of the nucleus of the reactor which will provide the necessary tritium for the fusion and will also serve as a shield. Lithium titanate has advantageous characteristics compared to other materials. Some of these are low activation under the irradiation of neutrons, good thermal stability, high density of lithium atoms and relatively fast tritium release at low temperatures. However, there are still several physical and chemical properties with respect to the tritium release mechanism and mechanical properties that have not been studied at all. This work presents a theoretical study of the electronic properties of lithium titanate ceramic and the corresponding tritiated material. Band calculations using the Extended H kel Tight-Binding approach were carried out. Results show that after substituting lithium for tritium atoms, the electronic states for the latter appear in the middle of prohibited band gap which it is an indication that the tritiated material should behave as a semiconductor, contrary to Li 2 TiO 3 which is a dielectric isolator. A study was also carried out to determine the energetically most favorable sites for the substitution of lithium for tritium atoms. Additionally, we analyzed possible pathways for the diffusion of a tritium atom within the crystalline structure of the Li 2 TiO 3

  15. Lanthanoid titanate film structure deposited at different temperatures in vacuum

    International Nuclear Information System (INIS)

    Kushkov, V.D.; Zaslavskij, A.M.; Mel'nikov, A.V.; Zverlin, A.V.; Slivinskaya, A.Eh.

    1991-01-01

    Influence of deposition temperature on the structure of lanthanoid titanate films, prepared by the method of high-rate vacuum condensation. It is shown that formation of crystal structure, close to equilibrium samples, proceeds at 1100-1300 deg C deposition temperatures. Increase of temperature in this range promotes formation of films with higher degree of structural perfection. Amorphous films of lanthanoid titanates form at 200-1000 deg C. Deposition temperature shouldn't exceed 1400 deg C to prevent the formation of perovskite like phases in films

  16. Internal gravity waves in Titan's atmosphere observed by Voyager radio occultation

    Science.gov (United States)

    Hinson, D. P.; Tyler, G. L.

    1983-01-01

    The radio scintillations caused by scattering from small-scale irregularities in Titan's neutral atmosphere during a radio occultation of Voyager 1 by Titan are investigated. Intensity and frequency fluctuations occurred on time scales from about 0.1 to 1.0 sec at 3.6 and 13 cm wavelengths whenever the radio path passed within 90 km of the surface, indicating the presence of variations in refractivity on length scales from a few hundred meters to a few kilometers. Above 25 km, the altitude profile of intensity scintillations closely agrees with the predictions of a simple theory based on the characteristics of internal gravity waves propagating with little or no attenuation through the vertical stratification in Titan's atmosphere. These observations support a hypothesis of stratospheric gravity waves, possibly driven by a cloud-free convective region in the lowest few kilometers of the stratosphere.

  17. TITAN: an advanced three-dimensional neutronics/thermal-hydraulics code for light water reactor safety analysis

    International Nuclear Information System (INIS)

    Griggs, D.P.; Kazimi, M.S.; Henry, A.F.

    1982-01-01

    The initial development of TITAN, a three-dimensional coupled neutronics/thermal-hydraulics code for LWR safety analysis, has been completed. The transient neutronics code QUANDRY has been joined to the two-fluid thermal-hydraulics code THERMIT with the appropriate feedback mechanisms modeled. A detailed steady-state and transient coupling scheme based on the tandem technique was implemented in accordance with the important structural and operational characteristics of QUANDRY and THERMIT. A two channel sample problem formed the basis for steady-state and transient analyses performed with TITAN. TITAN steady-state results were compared with those obtained with MEKIN and showed good agreement. Null transients, simulated turbine trip transients, and a rod withdrawal transient were analyzed with TITAN and reasonable results were obtained

  18. Preparation of Li4Ti5O12 by solution ion-exchange of sodium titanate nanotube and evaluation of electrochemical performance

    International Nuclear Information System (INIS)

    Zhang, Jingwei; Zhang, Fenli; Li, Jiuhe; Cai, Wei; Zhang, Jiwei; Yu, Laigui; Jin, Zhensheng; Zhang, Zhijun

    2013-01-01

    Nano-sized spinel lithium titanate (Li 4 Ti 5 O 12 ) was synthesized using sodium titanate nanotube as precursor via a facile solution ion-exchange method in association with subsequent calcination treatment at relatively low temperature. The influences of precursors, ion-exchange condition, and calcination temperature on the microstructure and electrochemical performance of the products were studied. Results indicate that pure-phase Li 4 Ti 5 O 12 can be harvested from sodium titanate nanotube precursor through an ion-exchanging at room temperature and calcination at 500 °C. The products exhibit a better performance as Li-ion battery anode material than the counterparts prepared from protonic titanate nanotube (H-titanate) precursor. The reason may lie in that sodium titanate nanotube is easier than protonic titanate nanotube to synthesize lithium titanate without TiO 2 impurity, resulting in reduced electron transfer ability and Li-ion transport ability. The capacity of Li 4 Ti 5 O 12 prepared from sodium titanate nanotube is 146 mAh/g at 10 C, and it has only 0.7 % decay after 200 charge/discharge cycles

  19. Titan Submarine: Exploring the Depths of Kraken

    Data.gov (United States)

    National Aeronautics and Space Administration — Titan is unique in the outer solar system in that it is the only one of the bodies outside the Earth with liquid lakes and seas on its surface. The Titanian seas,...

  20. Noble gases, nitrogen, and methane from the deep interior to the atmosphere of Titan

    Science.gov (United States)

    Glein, Christopher R.

    2015-04-01

    Titan's thick N2-CH4 atmosphere is unlike any in the Solar System, and its origin has been shrouded in mystery for over half a century. Here, I perform a detailed analysis of chemical and isotopic data from the Cassini-Huygens mission to develop the hypothesis that Titan's (non-photochemical) atmospheric gases came from deep within. It is suggested that Titan's CH4, N2, and noble gases originated in a rocky core buried inside the giant satellite, and hydrothermal and cryovolcanic processes were critical to the creation of Titan's atmosphere. Mass balance and chemical equilibrium calculations demonstrate that all aspects of this hypothesis can be considered geochemically plausible with respect to contemporary observational, experimental, and theoretical knowledge. Specifically, I show that a rocky core with a bulk noble gas content similar to that in CI carbonaceous meteorites would contain sufficient 36Ar and 22Ne to explain their reported abundances. I also show that Henry's law constants for noble gases in relevant condensed phases can be correlated with the size of their atoms, which leads to expected mixing ratios for 84Kr (∼0.2 ppbv) and 132Xe (∼0.01 ppbv) that can explain why these species have yet to be detected (Huygens upper limit serpentinization). I show that sufficient CH4 can be produced to replenish Titan's atmosphere many times over in the face of irreversible photolysis and escape of CH4, which is consistent with the favored model of episodic cryovolcanic outgassing. There should also have been enough NH3 inside Titan so that its thermal decomposition in a hot rocky core can generate the observed atmospheric N2, and if correct this model would imply that Titan's interior has experienced vigorous hydrothermal processing. The similarity in 14N/15N between cometary NH3 and Titan's N2 is consistent with this picture. As for the isotopes in CH4, I show that their observed relative abundances can be explained by low-temperature (∼20 °C) equilibria

  1. Method of applying a coating to a steel plate

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, T; Murakami, S; Chihara, Y; Iijima, K

    1968-07-19

    An application of a coating material containing a radically or ionically polymerizable monomer that can be changed into a high molecular compound by irradiation with ionizing radiations is provided to protect steel from corrosion and the adhesion of organic material. In this irradiation, the radiation doses are not more than 30 Mrad. The coating material is at least one kind of vehicle selected from the group consisting of a radically or ionically polymerizable monomer, polymer, copolymer, or compound of this monomer. They are, for example, styrene, acrylate, methacrylate, vinyl pyridine and their derivatives, acrylonitrile, acrylamide, and other vinyl compounds, etc. The absorption doses may be 30 or less Mrad, but preferably in the range of from 10 to 1 Mrad. Advantages are that the auxiliary heating can be performed below 100/sup 0/C, and that hardening can be carried out below 50/sup 0/C. Furthermore, the irradiation time is shorter than 30 seconds; may kinds of vehicles can be used; and solvent is unnecessary. In one example, 15 parts of acrylamide, 40 parts of styrene and 45 parts of ethyl acrylate are copolymerized. This copolymer is dissolved into 100 parts of styrene and is mixed with 50 parts of rutile and 50 parts of yellow lead. The obtained vehicle is hardened with 10 Mrad. The coated film 30..mu.. thick shows no defects due to weathering after 3 months. In another example, a mixture of 80 parts of unsaturated polyester and 20 parts of ethylene dimethacrylate gives 3H by irradiation with 6 Mrad in inert gas.

  2. Coating compositions comprising bismuth-alloyed zinc

    DEFF Research Database (Denmark)

    2008-01-01

    The present application discloses (i) a coating composition comprising a particulate zinc-based alloyed material, said material comprising 0.05-0.7% by weight of bismuth (Bi), the D50 of the particulate material being in the range of 2.5-30 µm; (ii) a coated structure comprising a metal structure...... having a first coating of the zinc-containing coating composition applied onto at least a part of the metal structure in a dry film thickness of 5-100 µm; and an outer coating applied onto said zinc-containing coating in a dry film thickness of 30-200 µm; (iii) a particulate zinc-based alloyed material......, wherein the material comprises 0.05-0.7%(w/w) of bismuth (Bi), and wherein the D50 of the particulate material is in the range of 2.5-30 µm; (iv) a composite powder consisting of at least 25%(w/w) of the particulate zinc-based alloyed material, the rest being a particulate material consisting of zinc...

  3. Thermal stability of titanate nanotubes

    Czech Academy of Sciences Publication Activity Database

    Králová, Daniela; Kužel, R.; Kovářová, Jana; Dybal, Jiří; Šlouf, Miroslav

    2009-01-01

    Roč. 16, 2a (2009), s. 41-43 ISSN 1211-5894. [Struktura - Colloquium of Czech and Slovak Crystallographic Association. Hluboká nad Vltavou, 22.06.2009-25.06.2009] R&D Projects: GA ČR GA203/07/0717; GA AV ČR KAN200520704 Institutional research plan: CEZ:AV0Z40500505 Keywords : titanate nanotubes * thermal stability Subject RIV: CD - Macromolecular Chemistry

  4. The MR-TOF-MS isobar separator for the TITAN facility at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Jesch, Christian; Dickel, Timo, E-mail: t.dickel@gsi.de; Plaß, Wolfgang R. [Justus-Liebig-University (Germany); Short, Devin [Simon Fraser University (Canada); Ayet San Andres, Samuel [Justus-Liebig-University (Germany); Dilling, Jens [TRIUMF (Canada); Geissel, Hans; Greiner, Florian; Lang, Johannes [Justus-Liebig-University (Germany); Leach, Kyle G. [Simon Fraser University (Canada); Lippert, Wayne; Scheidenberger, Christoph [Justus-Liebig-University (Germany); Yavor, Mikhail I. [Institute for Analytical Instrumentation, Russian Academy of Science (Russian Federation)

    2015-11-15

    At TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN) a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) will extend TITAN’s capabilities and facilitate mass measurements and in-trap decay spectroscopy of exotic nuclei that so far have not been possible due to strong isobaric contamination. This MR-TOF-MS will also enable mass measurements of very short-lived nuclides (half-life > 1 ms) that are produced in very low quantities (a few detected ions overall). In order to allow the installation of an MR-TOF-MS in the restricted space on the platform, on which the TITAN facility is located, novel mass spectrometric methods have been developed. Transport, cooling and distribution of the ions inside the device is done using a buffer gas-filled RFQ-based ion beam switchyard. Mass selection is achieved using a dynamic retrapping technique after time-of-flight analysis in an electrostatic isochronous reflector system. Only due to the combination of these novel methods the realization of an MR-TOF-MS based isobar separator at TITAN has become possible. The device has been built, commissioned off-line and is currently under installation at TITAN.

  5. A Three-Dimensional View of Titan's Surface Features from Cassini RADAR Stereogrammetry

    Science.gov (United States)

    Kirk, R. L.; Howington-Kraus, E.; Redding, B. L.; Becker, T. L.; Lee, E. M.; Stiles, B. W.; Hensley, S.; Hayes, A.; Lopes, R. M.; Lorenz, R. D.; Mitchell, K. L.; Radebaugh, J.; Paganelli, F.; Soderblom, L. A.; Stofan, E. R.; Wood, C. A.; Wall, S. D.; Cassini RADAR Team

    2008-12-01

    As of the end of its four-year Prime Mission, Cassini has obtained 300-1500 m resolution synthetic aperture radar images of the surface of Titan during 19 flybys. The elongated image swaths overlap extensively, and ~2% of the surface has now been imaged two or more times. The majority of image pairs have different viewing directions, and thus contain stereo parallax that encodes information about Titan's surface relief over distances of ~1 km and greater. As we have previously reported, the first step toward extracting quantitative topographic information was the development of rigorous "sensor models" that allowed the stereo systems previously used at the USGS and JPL to map Venus with Magellan images to be used for Titan mapping. The second major step toward extensive topomapping of Titan has been the reprocessing of the RADAR images based on an improved model of the satellite's rotation. Whereas the original images (except for a few pairs obtained at similar orbital phase, some of which we have mapped previously) were offset by as much as 30 km, the new versions align much better. The remaining misalignments, typically carbono)logic" cycle of precipitation, evaporation, and surface and subsurface fluid flow?

  6. Environmental risks and environmental justice, or how titanic risks are not so titanic after all.

    Science.gov (United States)

    Alario, Margarita V; Freudenburg, William R

    2010-01-01

    Some of the best-known social scientific theories of risks are those that have been elaborated by Anthony Giddens and Ulrich Beck. Although their arguments differ greatly, they agree in seeing the technologically induced risks of today's "Risk Society" as global - so pervasive that they transcend all socioeconomic as well as geopolitical and national boundaries. Most empirical work, however, provides greater support for a theoretical tradition exemplified by Short and Erikson. In this paper, we argue that many of the technological mega-risks described by Giddens and Beck as "transcending" social boundaries are better described as "Titanic risks," referring not so much to their colossal impact as to the fact that - as was the case for the majority of the victims on the Titanic - actual risks are related to victims' socioeconomic as well as sociogeographic locations. Previous research has shown this to be the case with high-risk technologies, such as nuclear energy and weaponry, and also with localized ones, such as toxic waste disposal. This article illustrates that the same is true even for the most genuinely "global" risks of all, namely those associated with global climate disruption.

  7. All Aboard the "Titanic": Character Journals Are Just the Tip of the Iceberg.

    Science.gov (United States)

    Mercurio, Mia Lynn

    1999-01-01

    Describes how a 7th-grade reading class used character journals to explore the sailing and the sinking of the "Titanic." Describes how the students took ownership of their research and enjoyed reading and writing about actual events as they became a passenger or crew member aboard the "Titanic," explored the ship, experienced…

  8. METHOD OF PROTECTIVELY COATING URANIUM

    Science.gov (United States)

    Eubank, L.D.; Boller, E.R.

    1959-02-01

    A method is described for protectively coating uranium with zine comprising cleaning the U for coating by pickling in concentrated HNO/sub 3/, dipping the cleaned U into a bath of molten zinc between 430 to 600 C and containing less than 0 01% each of Fe and Pb, and withdrawing and cooling to solidify the coating. The zinccoated uranium may be given a; econd coating with another metal niore resistant to the corrosive influences particularly concerned. A coating of Pb containing small proportions of Ag or Sn, or Al containing small proportions of Si may be applied over the zinc coatings by dipping in molten baths of these metals.

  9. Silane based coating of aluminium mold

    DEFF Research Database (Denmark)

    2013-01-01

    having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding...... of structures which would otherwise be difficult to mold. The resistance of the coated aluminium mold is significantly improved by applying a silane-based coating layer....

  10. Fatigue-free lead zirconate titanate-based capacitors for nonvolatile memories

    International Nuclear Information System (INIS)

    Shannigrahi, S. R.; Jang, Hyun M.

    2001-01-01

    The development of lead zirconate titanate (PZT)-based capacitors has been a long time goal of ferroelectric random access memories (FRAM). However, PZT-based perovskites with common platinum (Pt) electrodes have suffered from a significant reduction of the remanent polarization (P r ) after a certain number of read/write cycles (electrical fatigue). We now report the development of fatigue-free lanthanum-modified PZT capacitors using common Pt electrodes. The capacitors fabricated at 580 o C by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5 x 10 10 switching cycles, a quite stable charge retention profile with time, and comparatively high P r values, all of which assure their suitability for practical FRAM applications. Copyright 2001 American Institute of Physics

  11. Heteronanostructure of Ag particle on titanate nanowire membrane with enhanced photocatalytic properties and bactericidal activities

    International Nuclear Information System (INIS)

    Shang Lu; Li Bingjie; Dong Wenjun; Chen Benyong; Li Chaorong; Tang Weihua; Wang Ge; Wu Jian; Ying Yibin

    2010-01-01

    A novel seed induced method has been developed for syntheses of Ag particles on titanate nanowires, and then the heteronanostructured Ag/titanate nanowires were assembled into porous, flexible membranes. These titanate nanowires were about several hundreds micrometers in length and about 80 nm in diameter. The size of the Ag particle can be tuned within 300-700 nm. The pore size and thickness of the heteronanostructured membrane were easily controlled. An Ag/titanate nanowire membrane reactor has been developed to study the photocatalytic degradation of methamidophos in aqueous solution, and 87.0% of the methamidophos can be degraded in a concurrent filtration and photocatalytic oxidation process. The antibacterial activity was also investigated on the heteronanostructured membrane with UVA light (365 nm) irradiation, and a 99.99% satisfactory antibacterial effect on Escherichia coli was achieved.

  12. NEITSYTMATKA BIBLIOGRAFIOIDEN MAAILMAAN JÄÄVUORIA VÄISTELLEN : Bibliografia Titanic-tietoteoksista

    OpenAIRE

    Posio, Paula

    2016-01-01

    Titanic on saavuttanut myyttiset mittasuhteet reilussa sadassa vuodessa. Onnettomuus oli merenkulun historiassa poikkeuksellinen ja yhden aikakauden loppu. Titanicista ja onnettomuudesta on selvittämättä paljon asioita, ja osa jääneekin mysteeriksi. Lisäksi tutkijat taistelevat aikaa vastaan monessa asiassa. Nämä seikat saavat tutkijat edelleen tutkimaan aihetta eri puolilta. Tämä opinnäytetyö on toiminnallinen opinnäytetyö, jossa on laadittu Titanic-tutkija Juha Peltoselle bibliografia e...

  13. SOL-GEL SILICA-BASED Ag–Ca–P COATINGS WITH AGRESSIVE PRETREATMENT OF TITANIUM SUBSTRATE

    Directory of Open Access Journals (Sweden)

    ELENA BORSHCHEVA

    2011-12-01

    Full Text Available The aim of the experiment was the obtaining of thin silica coatings on titanium by sol-gel method, using mechanical (SiC - paper No.180 and chemical (leaching in HF pretreatments of the titanium substrates. The solutions were based on TEOS. For the sol-gel dipping process 4 different solutions were prepared: silica, silica with AgNO3 and silica + AgNO3 with brushite (CaHPO4·2H2O or monetite (CaHPO4 powders. The solutions were aged for 7 and 14 days at laboratory temperature. After sol-gel dip-coating process the samples were dried and fired. The adhesion of fired coatings was measured by tape test according to ASTM procedure and the bioactivity of the coatings was tested using in vitro test. The surfaces of the samples after firing, tape test and in vitro test were observed with the optical and electron microscopes. The firing results showed that silica-silver coatings did not change, brushite sol-gel coatings have cracked and the monetite sol-gel coatings have cracked also, but less than brushite ones. In spite of coating´s crackings, the square’s frames made on the surfaces were without any breakdowns after tape tests and the adhesion of all coatings was very good, classified by the highest grade 5. The results of in vitro tests showed that all coatings interacted with simulated body fluid (SBF. After exposition in SBF the new layer formed on substrates. In case of 7 days aged coatings containing brushite the new layer was uniform and compact. In case of 7 days aged coatings containing monetite the new layer was formed by crystals aggregated tightly together. The monetite and brushite coatings prepared from 14 days aged sol were the same as previous ones, but they were thicker. X-ray analyses after in vitro test confirmed dellaite, titanate and hydroxyapatite phases.

  14. Direct tritium measurement in lithium titanate for breeding blanket mock-up experiments with D-T neutrons

    International Nuclear Information System (INIS)

    Klix, A.; Ochiai, K.; Nishitani, T.; Takahashi, A.

    2004-01-01

    At Fusion Neutronics Source (FNS) of JAERI, tritium breeding experiments with blanket mock-ups consisting of advanced fusion reactor materials are in progress. The breeding zones are thin layers of lithium titanate which is one of the candidate tritium breeder materials for the DEMO fusion power reactor. It is anticipated that the application of small pellet-shaped lithium titanate detectors manufactured from the same material as the breeding layer will reduce experimental uncertainties arising from necessary corrections due to different isotopic lithium volume concentrations in breeding material and detector. Therefore, a method was developed to measure the local tritium production by means of lithium titanate pellet detectors and a liquid scintillation counting technique. The lithium titanate pellets were dissolved in concentrated hydrochloric acid solution and the resulting acidic solution was neutralized. Two ways of further processing were followed: direct incorporation into a liquid scintillation cocktail and distillation of the solution followed by mixing with liquid scintillator. Two types of lithium titanate pellets were investigated with different 6 Li enrichment and manufacturing procedure. It was found that lithium titanate is suitable for tritium production measurements. However some discrepancies in the measurement accuracy remained with one of the investigated pellet detectors when compared with a well-established lithium carbonate measurement technique and this issue needs further investigation

  15. Surface coating of graphite pebbles for Korean HCCR TBM

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngmin [National Fusion Research Institute, Daejeon (Korea, Republic of); Yun, Young-Hoon, E-mail: yunh2@dsu.ac.kr [Dongshin University, Naju (Korea, Republic of); Park, Yi-Hyun; Ahn, Mu-Young; Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Highlights: • A CVR-SiC coating was successfully formed on graphite pebbles for neutron reflector. • Dense and fine-grained surface morphologies of the SiC coatings were observed. • Oxidation resistance of the CVR-SiC-coated graphite pebbles was improved. - Abstract: The new concept of the recently modified Helium-Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) is to adopt a graphite reflector in the form of a pebble bed. A protective SiC coating is applied to the graphite pebbles to prohibit their reaction with steam or air as well as dust generation during TBM operation. In this research, the chemical vapor reaction (CVR) method was applied to fabricate SiC-coated graphite pebbles in a silica source. Relatively dense CVR-SiC coating was successfully formed on the graphite pebbles through the reduction of the graphite phase with SiO gas that was simply created from the silica source at 1850 °C (2 h). The microstructural features, XRD patterns, pore-size distribution and oxidation behavior of the SiC-coated graphite pebbles were investigated. To develop the practical process, which will be applied for mass production hereafter, a novel alternative method was applied to form the layer of SiC coating on the graphite pebbles over the silica source.

  16. Surface coating of graphite pebbles for Korean HCCR TBM

    International Nuclear Information System (INIS)

    Lee, Youngmin; Yun, Young-Hoon; Park, Yi-Hyun; Ahn, Mu-Young; Cho, Seungyon

    2014-01-01

    Highlights: • A CVR-SiC coating was successfully formed on graphite pebbles for neutron reflector. • Dense and fine-grained surface morphologies of the SiC coatings were observed. • Oxidation resistance of the CVR-SiC-coated graphite pebbles was improved. - Abstract: The new concept of the recently modified Helium-Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) is to adopt a graphite reflector in the form of a pebble bed. A protective SiC coating is applied to the graphite pebbles to prohibit their reaction with steam or air as well as dust generation during TBM operation. In this research, the chemical vapor reaction (CVR) method was applied to fabricate SiC-coated graphite pebbles in a silica source. Relatively dense CVR-SiC coating was successfully formed on the graphite pebbles through the reduction of the graphite phase with SiO gas that was simply created from the silica source at 1850 °C (2 h). The microstructural features, XRD patterns, pore-size distribution and oxidation behavior of the SiC-coated graphite pebbles were investigated. To develop the practical process, which will be applied for mass production hereafter, a novel alternative method was applied to form the layer of SiC coating on the graphite pebbles over the silica source

  17. The effect of physiologic aqueous solutions on the perovskite material lead-lanthanum-zirconium titanate (PLZT): potential retinotoxicity.

    Science.gov (United States)

    Foster, William J; Meen, James K; Fox, Donald A

    2013-03-01

    Perovskite compounds, including lead-lanthanum-zirconium titanate (PLZT), have wide technological application because of their unique physical properties. The use of PLZT in neuro-prosthetic systems, such as retinal implants, has been discussed in a number of publications. Since inorganic lead is a retinotoxic compound that produces retinal degeneration, the long-term stability of PLZT in aqueous biological solutions must be determined. We evaluated the stability and effects of prolonged immersion of a PLZT-coated crystal in a buffered balanced salt solution. Scanning Electron Microscopy and Electron Dispersive Spectroscopy (EDS) using a JEOL JSM 5410 microscope equipped with EDS were utilized to evaluate the samples before and after prolonged immersion. We found that lead and other constituents of PLZT leached into the surrounding aqueous medium. By comparing the unit cell of PLZT with that of CaTiO(3), which has been found to react with aqueous fluids, Lead is in the same site in PLZT as Ca is in CaTiO(3). It is thus reasonable that PLZT will react with aqueous solutions. The results suggest that PLZT must either be coated with a protective layer or is not appropriate for long-term in vivo or in vitro biological applications.

  18. Satisfaction and complications with the Titan® one-touch release penile implant

    DEFF Research Database (Denmark)

    Lindeborg, Lisa; Fode, Mikkel; Fahrenkrug, Lasse

    2014-01-01

    OBJECTIVE: The aim of this study was to assess complication rates and patient satisfaction with Coloplast Titan® one-touch release (OTR) inflatable penile implants inserted at one university hospital centre between November 2008 and April 2011. MATERIAL AND METHODS: Overall, 33 patients with orga......OBJECTIVE: The aim of this study was to assess complication rates and patient satisfaction with Coloplast Titan® one-touch release (OTR) inflatable penile implants inserted at one university hospital centre between November 2008 and April 2011. MATERIAL AND METHODS: Overall, 33 patients...... with organic erectile dysfunction underwent penile implant surgery during the study period. The Titan OTR inflatable penile implants were inserted using a penoscrotal approach. Patient and partner satisfaction was assessed with the Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) questionnaire...

  19. Indentation plasticity of barium titanate single crystals: Dislocation influence on ferroelectric domain walls

    International Nuclear Information System (INIS)

    Liu, D.; Chelf, M.; White, K.W.

    2006-01-01

    The plastic behaviors of barium titanate (001) and (110) single crystals are studied with atomic force microscopy and piezoresponse force microscopy (PFM) following nanoindendation damage. Plastic deformation mechanisms of ferroelectric barium titanate single crystals are discussed with a focus on the interaction between PFM response and dislocation activities. Nanoindentation tests indicate that the theoretical strength is approached prior to the first pop-in event, consistent with the creation of dislocation nucleation sites required for the onset of plasticity. Surface topographic and piezoelectric analyses indicate that pile-ups around indents result from dislocation activities on the primary slip system, {110} pc pc . The more complex indentation-induced domain patterns observed on (110) barium titanate are also discussed

  20. FEI Titan G2 60-300 HOLO

    Directory of Open Access Journals (Sweden)

    Chris Boothroyd

    2016-02-01

    Full Text Available The FEI Titan G2 60-300 HOLO is a unique fourth generation transmission electron microscope, which has been specifically designed for the investigation of electromagnetic fields of materials using off-axis electron holography. It has a Lorentz lens to allow magnetic field free imaging plus two electron biprisms, which in combination enable more uniform holographic fringes to be used. The instrument also has an ultra-wide objective lens pole piece gap which is ideal for in situ experiments. For these purposes, the FEI Titan G2 60-300 HOLO is equipped with a Schottky type high-brightness electron gun (FEI X-FEG, an image Cs corrector (CEOS, a post-column energy filter system (Gatan Tridiem 865 ER as well as a 4 megapixel CCD system (Gatan UltraScan 1000 XP. Typical examples of use and technical specifications for the instrument are given below.

  1. Single-piece maintenance procedures for the TITAN reversed-field pinch reactor

    International Nuclear Information System (INIS)

    Grotz, S.P.; Creedon, R.L.; Cooke, P.I.H.; Duggan, W.P.; Krakowski, R.A.; Najmabadi, F.; Wong, C.P.C.

    1987-01-01

    The TITAN reactor is a compact (major radius of 3.9 m and minor plasma radius of 0.6 m), high neutron wall loading (--18MW/m 2 ) fusion energy system based on the reversed-field pinch (RFP) concept. The TITAN-I fusion power core (FPC) is a lithium, self-cooled design with vanadium alloy (V-3Ti-1Si) structural material. The compact design of the TITAN fusion power core (FPC) reduces the system to a few small and relatively low mass components, making toroidal segmentation of the FPC unnecessary. A single-piece maintenance procedure in which the replaceable first wall and blanket is removed as a single unit is, therefore, possible. The TITAN FPC design provides for top access to the reactor with vertical lifts used to remove the components. The number of remote handling procedures is few and the movements are uncomplicated. The annual torus replacement requires that the reusable ohmic-heating coil set and hot-shield assembly be removed and temporarily stored in a hot cell. The used first wall and blanket assembly is drained and disconnected from the coolant supply system, then lifted to a processing room where it is cooled and prepared for Class-C waste burial. The new, pre-tested first wall and blanket assembly is then lowered into position and the removal procedure is reversed to complete the replacement process

  2. Composition And Geometry Of Titan'S Dunes

    Science.gov (United States)

    Le Gall, Alice; Janssen, M. A.; Wye, L. C.; Lorenz, R. D.; Radebaugh, J.; Cassini RADAR Team

    2009-09-01

    Fields of linear dunes cover a large portion of Titan's equatorial regions. As the Cassini mission continues, more of them are unveiled and examined by the microwave Titan RADAR Mapper both in the active and passive modes of operation of the instrument and with an increasing variety of observational geometries. In this presentation, we will show that the joint analysis of the SAR (Synthetic Aperture Radar) and radiometry observations of the dunes at closest approach supports the idea of different composition between the dunes and the interdunes. It suggests that the icy bedrock of Titan may be exposed, or partially exposed, in the interdunes. We also see regional differences among dune fields. Dunes are highly directional features; their visibility is controlled by the look direction and the incidence angle. We have developed a backscatter and emissivity model that takes into account the topography of the dunes relative to the geometry of observation as well as the composition of the dunes and interdunes. Compared to observations and, in particular, to multiple observations of areas at the overlap of several swaths, we argue the need for a diffuse scattering mechanism. The presence of ripples in the dunes and/or interdunes might account for the recorded backscatter. In this presentation we will also report the results of the T61 experiment. The T61 HiSAR sequence (on August 25, 2009) was designed to examine a small region of the Shangri-La dune field with a substantial sampling of incidence angles around the direction perpendicular to the dunes long axis. The spot in question was already observed during the T55 SAR swath and the T61 experiment should allow us to determine the slope of the dunes.

  3. Study of the rheological properties of casting slips obtained from titanium oxide and bariun titanate in order to obtain pieces by means of casting in plaster moulds

    International Nuclear Information System (INIS)

    Amarante Junior, A.

    1986-01-01

    The behaviour of titanium-oxide (TiO 2 ) and barium titanate used in slip casting with plaster moulds is studied. Some data in several tests, as well as materials and methods applied are presented. (M.J.C.) [pt

  4. Storms in the tropics of Titan.

    Science.gov (United States)

    Schaller, E L; Roe, H G; Schneider, T; Brown, M E

    2009-08-13

    Methane clouds, lakes and most fluvial features on Saturn's moon Titan have been observed in the moist high latitudes, while the tropics have been nearly devoid of convective clouds and have shown an abundance of wind-carved surface features like dunes. The presence of small-scale channels and dry riverbeds near the equator observed by the Huygens probe at latitudes thought incapable of supporting convection (and thus strong rain) has been suggested to be due to geological seepage or other mechanisms not related to precipitation. Here we report the presence of bright, transient, tropospheric clouds in tropical latitudes. We find that the initial pulse of cloud activity generated planetary waves that instigated cloud activity at other latitudes across Titan that had been cloud-free for at least several years. These observations show that convective pulses at one latitude can trigger short-term convection at other latitudes, even those not generally considered capable of supporting convection, and may also explain the presence of methane-carved rivers and channels near the Huygens landing site.

  5. Chemistry in the Dunes of Titan: Tribochemical Reactions of Complex Organics and Water Ice

    Science.gov (United States)

    Beauchamp, J. L.; Thomas, D. A.

    2010-12-01

    Titan’s N2-CH4 atmosphere provides the starting material for a wide array of organic compounds to be formed via photochemistry, and the presence of unsaturated hydrocarbon, amine, and polycyclic aromatic species has been supported by data from the Cassini-Huygens mission [1,2]. Production of tholins by UV irradiation of a simulated N2-CH4 environment has yielded products that match the observed optical properties of Titan haze, suggesting that these compounds provide suitable analogs to Titan aerosol compounds [3, 4, 5]. Organics produced in Titan’s atmosphere eventually settle to the surface and very likely contribute to the particulate matter comprising the expansive longitudinal dune features observed at mid-latitudes [6]. Once on the surface, conditions that lead to incorporation of oxygen via contact with water ice or liquid water in Titan’s low temperature environment are of particular interest and have important implications for astrobiology [7; 8]. In this work, we postulate that the mechanical energy from wind-driven grains in the dunes of Titan can ultimately drive chemical processes and lead to the incorporation of oxygen into organic compounds via tribochemical reactions [9] and describe experiments designed to test this hypothesis. While the exact composition of the dunes of Titan is unknown, it is likely that they mainly comprise organic and water ice particles approximately 0.2 mm in diameter, the ideal size for saltation by the winds of Titan [6]. During the saltation process, organic particles undergo charging due to friction between particles, leading in turn to formation of ions and free radicals in localized electrical discharges at particle interfaces [10]. These reactive intermediates can initiate processes such as free radical and ionic polymerization that further transform organics. Of particular interest is the incorporation of oxygen into organic molecules, providing a pathway to the synthesis of biologically relevant compounds

  6. Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

    International Nuclear Information System (INIS)

    Hollis, Kendall J.; Pena, Maria I.

    2010-01-01

    Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

  7. Continuous fiber reinforced mesh bond coat for environmental barrier coating system

    Science.gov (United States)

    Zhang, James; Das, Rupak; Roberts III, Herbert Chidsey; Delvaux, John McConnell

    2017-09-26

    A gas turbine blade may have a bond coat applied to its surface. A porous substrate may be applied to the bond layer and one or more protective layers may be applied to the bond layer such that the fiber mesh is embedded between the bond layer and the protective layer to prevent creep.

  8. Spectroscopy, morphometry, and photoclinometry of Titan's dunefields from Cassini/VIMS

    Science.gov (United States)

    Barnes, J.W.; Brown, R.H.; Soderblom, L.; Sotin, Christophe; Le, Mouelic S.; Rodriguez, S.; Jaumann, R.; Beyer, R.A.; Buratti, B.J.; Pitman, K.; Baines, K.H.; Clark, R.; Nicholson, P.

    2008-01-01

    Fine-resolution (500 m/pixel) Cassini Visual and Infrared Mapping Spectrometer (VIMS) T20 observations of Titan resolve that moon's sand dunes. The spectral variability in some dune regions shows that there are sand-free interdune areas, wherein VIMS spectra reveal the exposed dune substrate. The interdunes from T20 are, variously, materials that correspond to the equatorial bright, 5-??m-bright, and dark blue spectral units. Our observations show that an enigmatic "dark red" spectral unit seen in T5 in fact represents a macroscopic mixture with 5-??m-bright material and dunes as its spectral endmembers. Looking more broadly, similar mixtures of varying amounts of dune and interdune units of varying composition can explain the spectral and albedo variability within the dark brown dune global spectral unit that is associated with dunes. The presence of interdunes indicates that Titan's dunefields are both mature and recently active. The spectrum of the dune endmember reveals the sand to be composed of less water ice than the rest of Titan; various organics are consistent with the dunes' measured reflectivity. We measure a mean dune spacing of 2.1 km, and find that the dunes are oriented on the average in an east-west direction, but angling up to 10?? from parallel to the equator in specific cases. Where no interdunes are present, we determine the height of one set of dunes photoclinometrically to be between 30 and 70 m. These results pave the way for future exploration and interpretation of Titan's sand dunes. ?? 2007 Elsevier Inc. All rights reserved.

  9. Reorientation Timescales and Pattern Dynamics for Titan's Dunes: Does the Tail Wag the Dog or the Dragon?

    Science.gov (United States)

    Ewing, R. C.; Hayes, A. G.; McCormick, C.; Ballard, C.; Troy, S. A.

    2012-04-01

    Fields of bedform patterns persist across many orders of magnitude, from cm-scale sub-aqueous current ripples to km-scale aeolian dunes, and form with surprisingly little difference in expression despite a range of formative environments. Because of the remarkable similarity among bedform patterns, extracting information about climate and environment from these patterns is a challenge. For example, crestline orientation is not diagnostic of a particular flow regime; similar patterns form under many different flow configurations. On Titan, these challenges have played out with many attempts to reconcile dune crestline orientation with modeled and expected wind regimes. We propose that thinking about the time-scale of the change in dune orientation, rather than the orientation itself, can provide new insights on the long-term stability of the dune-field patterns and the formative wind regime. In this work, we apply the crestline re-orientation model developed by Werner and Kocurek [Geology, 1997] to the equatorial dune fields of Titan. We use Cassini Synthetic Aperture Radar images processed through a de-noising algorithm recently developed by Lucas et al. [LPSC, 2012] to measure variations in pattern parameters (crest spacing, crest length and defect density, which is the number of defect pairs per total crest length) both within and between Titan's dune fields to describe pattern maturity and identify areas where changes in dune orientation are likely to occur (or may already be occurring). Measured defect densities are similar to Earth's largest linear dune fields, such as the Namib Sand Sea and the Simpson Desert. We use measured defect densities in the Werner and Kocurek model to estimate crestline reorientation rates. We find reorientation timescales varying from ten to a hundred thousand times the average migration timescale (time to migrate a bedform one meter, ~1 Titan year according to Tokano (Aeolian Research, 2010)). Well-organized patterns have the

  10. Thin coatings for heavy industry: Advanced coatings for pipes and valves

    Science.gov (United States)

    Vernhes, Luc

    characteristics suitable for applications such as pipes and valves. From these general objectives, three specific objectives were derived: 1) to select and assess the best candidates for alternatives to hard chromium electroplating, which has been classified by the U.S. Environmental Protection Agency (EPA) as an environmentally unfriendly process; 2) to investigate recurrent failures occurring in the field with thermal sprayed HVOF Cr3C 2-NiCr coating applied to Inconel 718 PH when exposed to supercritical steam lines and thermal shocks in supercritical power plants (determining the root causes of coating failures and assessing potential coating alternatives to alleviate these issues); and 3) to develop new coating architectures, including complex microstructures and interfaces, and to better understand and optimize complex tribomechanical properties. The main results are presented in the form of articles in peer-reviewed journals. In the first article, a variety of chromium-free protective coatings were assessed as alternatives to hard chromium (HC) electroplating, such as nanostructured cobalt-phosphor (NCP) deposited by electroplating and tungsten/tungsten carbide (W/WC) applied by chemical vapor deposition. In order to compare performance across the coatings, a series of laboratory tests were performed, including hardness, microscratch, pin-on-disk, and electrochemical polarization measurements. Mechanical and fatigue resistance were also determined using prototype valves with coated ball under severe tribocorrosion conditions. It was found that W/WC coating exhibits superior wear and corrosion resistance due to high hardness and high pitting resistance, respectively, whereas NCP exhibits better wear resistance than HC with alumina ball as well as low corrosion potential, making it suitable for use as sacrificial protective coating. Both nanostructured coatings exhibited superior tribomechanical and functional characteristics compared to HC. The second article presents an

  11. Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators.

    Science.gov (United States)

    Reichmann, Klaus; Feteira, Antonio; Li, Ming

    2015-12-04

    The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.

  12. Applications of inorganic ion exchangers; I-sorption and fixation of some radionuclides in synthetic iron (III)titanate ion exchanger

    International Nuclear Information System (INIS)

    Abou-Mesalam, M.M.; El-Naggar, I.M.

    2002-01-01

    Iron(III) titanate as inorganic ion exchange material has been synthesized by addition of ferric nitrate solution to titanium tetrachloride (dissolved in 4M HCI) with molar ratio equal to unity. The data obtained proposed that the chemical formula of iron(III) titanate may written either as Fe 1 .3 (TiO). 2h 2 O or Fe(TiO 4 ) 0 .76.1.5H 2 O. The surface area values of unloaded and loaded iron(III) titanate with Cs + , Co 2 + and Eu 3 + ions were measured using BET-technique. The selectiy sequence for sorption of Cs + , Co 2 + and Fu 3 + ions on iron (III) titanate was found to be; Co 2 + > Eu 3 + > Cs + . The leach rate values of Cs + , Co 2 + and Fu 3 + ions from iron (II) titanate heated to 1000 degree C different leachants were determined and shows lower values compared to those obtained from unheated iron (III) titanate (dried at 50 degree C) which elucidate the suitability of iron (III) titanate in fixation of Cs + , Co 2 + and Eu 3 + ions by thermal treatment up to1000 degree.

  13. The development of CVR coatings for PBR fuels

    Science.gov (United States)

    Barletta, R. E.; Vanier, P. E.; Dowell, M. B.; Lennartz, J. A.

    Particle bed reactors (PBR's) are being developed for both space power and propulsion applications. These reactors operate with exhaust gas temperatures of 2500 to 3000 K and fuel temperatures hundreds of degrees higher. One fuel design for these reactors consists of uranium carbide encapsulated in either carbon or graphite. This fuel kernel must be protected from the coolant gas, usually H2, both to prevent attack of the kernel and to limit fission product release. Refractory carbide coatings have been proposed for this purpose. The typical coating process used for this is a chemical vapor deposition. Testing of other components have indicated the superiority of refractory carbide coatings applied using a chemical vapor reaction (CVR) process, however technology to apply these coatings to large numbers of fuel particles with diameters on the order of 500 pm were not readily available. A process to deposit these CVR coatings on surrogate fuel consisting of graphite particles is described. Several types of coatings have been applied to the graphite substrate: NbC in various thicknesses and a bilayer coating consisting of NbC and TaC with a intermediate layer of pyrolytic graphite. These coated particles have been characterized prior to test; results are presented.

  14. ETV Program Report: Coatings for Wastewater Collection ...

    Science.gov (United States)

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Material and Technology (CIGMAT) Laboratory at the University of Houston. Testing was conducted over a period of six months to evaluate the coating’s (1) chemical resistance and (2) bonding strength for infrastructure applications. For chemical resistance, coated concrete and clay bricks with holidays (holes created in the coating) were used to evaluate the chemical resistance of the coating/substrate bond under a corrosive environment. Twenty coated concrete (dry and wet) and 20 coated clay brick (dry and wet) specimens were exposed to DI water and sulfuric acid solution (pH=1), and the specimens were visually inspected and weight changes measured. Evaluation of the coating-to-substrate bonding strength was determined using two modified ASTM test methods – one to determine bond strength of the coating with two specimens sandwiched together using the coating, and the second to determine the bond strength by applying a tensile load to the coating applied to specimens of each substrate. Forty-eight bonding tests were performed over the six month evaluation. The tests resulted in the following conclusions about Standard Cement’s SEC 4553 coating: • After the six-month chemi

  15. Computational homogenisation for thermoviscoplasticity: application to thermally sprayed coatings

    Science.gov (United States)

    Berthelsen, Rolf; Denzer, Ralf; Oppermann, Philip; Menzel, Andreas

    2017-11-01

    Metal forming processes require wear-resistant tool surfaces in order to ensure a long life cycle of the expensive tools together with a constant high quality of the produced components. Thermal spraying is a relatively widely applied coating technique for the deposit of wear protection coatings. During these coating processes, heterogeneous coatings are deployed at high temperatures followed by quenching where residual stresses occur which strongly influence the performance of the coated tools. The objective of this article is to discuss and apply a thermo-mechanically coupled simulation framework which captures the heterogeneity of the deposited coating material. Therefore, a two-scale finite element framework for the solution of nonlinear thermo-mechanically coupled problems is elaborated and applied to the simulation of thermoviscoplastic material behaviour including nonlinear thermal softening in a geometrically linearised setting. The finite element framework and material model is demonstrated by means of numerical examples.

  16. Miller-Urey Experiments to Assess the Production of Amino Acids under Impact Conditions on Early Titan

    Science.gov (United States)

    Turse, Carol; Khan, A.; Leitner, J. J.; Firneis, M. G.; Schulze-Makuch, D.

    2012-05-01

    We performed Miller-Urey type experiments to determine the organic synthesis of amino acids under conditions that have likely occurred on Saturn's moon Titan and are also relevant to Jupiter's moon Europa. We conducted the first set of experiments under early Earth conditions, similar to the original Miller-Urey experiments (Miller, 1953). In brief, the 250ml round bottom flask was filled with approximately 200mL of filtered sterile water and the apparatus was placed under vacuum for 10 minutes to purge the water of gases. The system was then flushed with hydrogen gas and placed under vacuum three times. Gases were then added in the following order: hydrogen gas to 0.1 bar, methane gas to 0.45 bar and ammonia to 0.45 bar ( 1bar total). The water was then brought to a boil and the spark was applied using the tesla coil up to a maximum of 50,000 volts. The apparatus was run for approximately 5-7 days. Between the runs the apparatus was cleaned using a hot 10% sodium hydroxide solution followed by a dilute sulfuric acid wash and four rinses with Millipure water. In the second set of experiments we simulated conditions that could have existed on an early, warm Titan or after an asteroid strike on Titan (Schulze-Makuch and Grinspoon, 2005), particularly if the strike would have occurred in the subpolar areas that exhibit vast ethane-methane lakes. If the asteroid or comet would be of sufficient size, it would also puncture the icy crust and access a vast reservoir of the subsurface liquid ammonia-water mixture. Thompson and Sagan (1992) showed that a liquid water-ammonia body could exist for millions of years on Titan after an asteroid impact. Thus, we modified the experimental conditions as described above and report on the results. Assuming a moderate impact in the subpolar areas of Titan, we used an atmosphere of currently 1.5 bar, but increased the partial pressure of methane to 1 bar (and 0.1 bar ammonia assuming a minor amount of ammonia-water ice being evaporated

  17. Tribological coatings for liquid metal and irradiation environments

    International Nuclear Information System (INIS)

    Johnson, R.N.

    1986-01-01

    Several metallurgical coatings have been developed that provide good tribological performances in high-temperature liquid sodium and that are relatively unaffected by neutron fluences to 6 X 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). The coatings that have consistently provided the best tribological performance have been the nickel aluminide diffusion coatings created by the pack cementation process, chromium carbide or Tribaloy 700 trade mark (a nickel-base hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing materials applied by the electro-spark deposition process. The latter process is a relatively recent development for nuclear applications and is expected to find wide usage. Other coating processes, such as plasma-spray coating, sputtering, and chemical vapor deposition, were candidates for use on various components, but the coatings did not pass the required qualification tests or were not economically competitive. The advantages and limitations of the three selected processes are discussed, the tribological performance of the coatings is reviewed, and representative applications and their performance requirements are described

  18. Upper limit set for level of lightning activity on Titan

    Science.gov (United States)

    Desch, M. D.; Kaiser, M. L.

    1990-01-01

    Because optically thick cloud and haze layers prevent lightning detection at optical wavelength on Titan, a search was conducted for lightning-radiated signals (spherics) at radio wavelengths using the planetary radioastronomy instrument aboard Voyager 1. Given the maximum ionosphere density of about 3000/cu cm, lightning spherics should be detectable above an observing frequency of 500 kHz. Since no evidence for spherics is found, an upper limit to the total energy per flash in Titan lightning of about 10 to the 6th J, or about 1000 times weaker than that of typical terrestrial lightning, is inferred.

  19. Organic chemistry in the atmosphere. [laboratory modeling of Titan atmosphere

    Science.gov (United States)

    Sagan, C.

    1974-01-01

    The existence of an at least moderately complex organic chemistry on Titan is stipulated based on clear evidence of methane, and at least presumptive evidence of hydrogen in its atmosphere. The ratio of methane to hydrogen is the highest of any atmosphere in the solar system. Irradiation of hydrogen/methane mixtures produces aromatic and aliphatic hydrocarbons. A very reasonable hypothesis assumes that the red cloud cover of Titan is made of organic chemicals. Two-carbon hydrocarbons experimentally produced from irradiated mixtures of methane, ammonia, water, and hydrogen bear out the possible organic chemistry of the Titanian environment.

  20. Statistical experimental design for refractory coatings

    International Nuclear Information System (INIS)

    McKinnon, J.A.; Standard, O.C.

    2000-01-01

    The production of refractory coatings on metal casting moulds is critically dependent on the development of suitable rheological characteristics, such as viscosity and thixotropy, in the initial coating slurry. In this paper, the basic concepts of mixture design and analysis are applied to the formulation of a refractory coating, with illustration by a worked example. Experimental data of coating viscosity versus composition are fitted to a statistical model to obtain a reliable method of predicting the optimal formulation of the coating. Copyright (2000) The Australian Ceramic Society

  1. Experimental measurement of effective thermal conductivity of packed lithium-titanate pebble bed

    International Nuclear Information System (INIS)

    Mandal, D.; Sathiyamoorthy, D.; Vinjamur, M.

    2012-01-01

    Lithium titanate is a promising solid breeder material for the fusion reactor blanket. Packed lithium titanate pebble bed is considered for the blanket. The thermal energy; that will be produced in the bed during breeding and the radiated heat from the reactor core absorbed must be removed. So, the experimental thermal property data are important for the blanket design. In past, a significant amount of works were conducted to determine the effective thermal conductivity of packed solid breeder pebble bed, in helium atmosphere, but no flow of gas was considered. With increase in gas flow rate, effective thermal conductivity of pebble bed increases. Particle size and void fraction also affect the thermal properties of the bed significantly. An experimental facility with external heat source was designed and installed. Experiments were carried out with lithium-titanate pebbles of different sizes at variable gas flow rates and at different bed wall temperature. It was observed that effective thermal conductivity of pebble bed is a function of particle Reynolds number and temperature. From the experimental data two correlations have been developed to estimate the effective thermal conductivity of packed lithium-titanate pebble bed for different particle Reynolds number and at different temperatures. The experimental details and results are discussed in this paper.

  2. Evidence for the existence of supercooled ethane droplets under conditions prevalent in Titan's atmosphere.

    Science.gov (United States)

    Sigurbjörnsson, Omar F; Signorell, Ruth

    2008-11-07

    Recent evidence for ethane clouds and condensation in Titan's atmosphere raise the question whether liquid ethane condensation nuclei and supercooled liquid ethane droplets exist under the prevalent conditions. We present laboratory studies on the phase behaviour of pure ethane aerosols and ethane aerosols formed in the presence of other ice nuclei under conditions relevant to Titan's atmosphere. Combining bath gas cooling with infrared spectroscopy, we find evidence for the existence of supercooled liquid ethane aerosol droplets. The observed homogeneous freezing rates imply that supercooled ethane could be a long-lived species in ethane-rich regions of Titan's atmosphere similar to supercooled water in the Earth's atmosphere.

  3. Indentation plasticity of barium titanate single crystals: Dislocation influence on ferroelectric domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [Department of Mechanical Engineering, University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)]. E-mail: duo.liu@mail.uh.edu; Chelf, M. [Department of Mechanical Engineering, University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States); White, K.W. [Department of Mechanical Engineering, University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)

    2006-10-15

    The plastic behaviors of barium titanate (001) and (110) single crystals are studied with atomic force microscopy and piezoresponse force microscopy (PFM) following nanoindendation damage. Plastic deformation mechanisms of ferroelectric barium titanate single crystals are discussed with a focus on the interaction between PFM response and dislocation activities. Nanoindentation tests indicate that the theoretical strength is approached prior to the first pop-in event, consistent with the creation of dislocation nucleation sites required for the onset of plasticity. Surface topographic and piezoelectric analyses indicate that pile-ups around indents result from dislocation activities on the primary slip system, {l_brace}110{r_brace}{sub pc}<11-bar 0>{sub pc}. The more complex indentation-induced domain patterns observed on (110) barium titanate are also discussed.

  4. Phase 1 Final Report: Titan Submarine

    Science.gov (United States)

    Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.

    2015-01-01

    The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase 1 for 2014. The proposal stated the desire to investigate what science a submarine for Titan's liquid hydrocarbon seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (100 kg), it was found that a submersible platform can accomplish extensive science both above and below the surface of the Kraken Mare. Submerged science includes mapping using side-looking sonar, imaging and spectroscopy of the lake, as well as sampling of the lake's bottom and shallow shoreline. While surfaced, the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 km inland. This imaging requirement pushed the landing date to Titan's next summer period (2047) to allow for lighted conditions, as well as direct-to-Earth communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid, sediment, and chemical interactions. An estimated 25 Mb of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system.The baseline 90-day mission would be to sail submerged and surfaced around and through Kraken Mare investigating the shoreline and inlets to evaluate the sedimentary interaction both on the surface and then below. Depths of Kraken have yet to be sensed (Ligeia to the north is thought to be 200 m (656 ft) deep), but a maximum depth of 1,000 m (3,281 ft) for Kraken Mare was assumed for the design). The sub would spend 20 d at the interface between Kraken Mare and Ligeia Mare for clues to the drainage of

  5. Electrophoretic growth of lead zirconate titanate nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Limmer, S.J.; Seraji, S.; Forbess, M.J.; Wu Yun; Chou, T.P.; Nguyen, C.; Cao Guozhong [Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering

    2001-08-16

    Nanorods of lead zirconate titanate (PZT)-a ferro- and piezoelectric material-up to 10 {mu}m in length and 70 to 150 nm in diameter are produced by sol-gel electrophoresis of PZT in a track-etched polycarbonate membrane, which is used as a template. (orig.)

  6. Insights on landscape evolution and climatic forcing on Titan

    Science.gov (United States)

    Lucas, A.; Daudon, C.; Rodriguez, S.; Cornet, T.; Perron, J. T.

    2017-12-01

    The landscapes of Titan were observed for nearly 13 years by the Cassini spacecraft and Huygens probe. With dunes, mountains, seas, lakes, rivers..., the great morphological variety observed testifies to the geological richness that Titan shares with the Earth. In this study, we combine analysis of radar and hyperspectral data provided by the Cassini-Huygens mission, with models of valley and river network evolution to better understand the processes at work that sculpt these familiar landscapes. We develop quantitative criteria for comparing 3D morphologies obtained by numerical simulation with those derived for Titan by photogrammetry. These criteria are validated on Earth's landscapes. We simulate morphologies similar to those observed and show that landscapes at the equator and poles are mainly controlled by river incision and mass wasting such as landslides for which we quantify their respective contribution. Subsequently, we relate modeling to precipitation rates of methane and show values that are to be compared with general circulation model predictions (GCM). Our results also show a very young age of formation of the observed morphologies, less than a few million years. Finally, we provide new constraints on current amplitude of the tidal effects and organic precipitation rates from atmosphere chemistry.

  7. Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

    International Nuclear Information System (INIS)

    Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

    2008-01-01

    In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

  8. Capture of toxic radioactive and heavy metal ions from water by using titanate nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jiasheng, E-mail: jiashengxu@bhu.edu.cn [Liaoning Province Key Laboratory for Synthesis and Application of Functional Compounds, College of Chemistry, Chemical Engineering and Food Safety, Center of Science and Technology Experiment, Bohai University, 19 Sci-tech Road, Jinzhou 121013 (China); Zhang, He; Zhang, Jie [Liaoning Province Key Laboratory for Synthesis and Application of Functional Compounds, College of Chemistry, Chemical Engineering and Food Safety, Center of Science and Technology Experiment, Bohai University, 19 Sci-tech Road, Jinzhou 121013 (China); Kim, Eui Jung [School of Chemical Engineering and Bioengineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

    2014-11-25

    Highlights: • Three types of titanate nanofibers were prepared via a hydrothermal porcess. • These nanofibers show availability for removal of the toxic ions from water. • The equilibrium data were fitted well with the Langmuir model. - Abstract: Three types of titanate nanofibers (sodium titanate nanofibers (TNF-A), potassium/sodium titanate nanofibers (TNF-B), potassium titanate nanofibers (TNF-C)) were prepared via a hydrothermal treatment of anatase powders in different alkali solutions at 170 °C for 96 h, respectively. The as-prepared nanofibers have large specific surface area and show availability for the removal of radioactive and heavy metal ions from water system, such as Ba{sup 2+} (as substitute of {sup 226}Ra{sup 2+}) and Pb{sup 2+} ions. The TNF-A shows a better capacity in the removal of Ba{sup 2+} and Pb{sup 2+} than TNF-B and TNF-C. Structural characterization of the materials was performed with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and with inductively coupled plasma optical emission spectrometry (ICP-OES). It is found that the equilibrium data fit well with the Langmuir model. This study highlights that nanoparticles of inorganic ion exchangers with layered structure are potential materials for efficient removal of the toxic ions from contaminated water.

  9. Nanosized lithium titanates produced by plasma technique

    International Nuclear Information System (INIS)

    Grabis, J; Orlovs, A; Rasmane, Dz

    2007-01-01

    The synthesis of nanosized lithium titanates is studied by evaporation of coarse grained commercially available titanium and lithium carbonate particles in radio-frequency plasma flow with subsequent controlling formation and growth conditions of product particles. In accordance with the XRD analysis the phase composition of the obtained powders is determined by feeding rate of precursors and strongly by ratio of lithium and titanium. The Li 2 TiO 3 and Li 4 Ti 5 O 12 particles containing small amounts of extra phases were obtained at ratio of Li/Ti = 2 and Li/Ti = 0.8 respectively, feeding rate of precursors being in the range of 0.6-0.9 kg/h. Specific surface area of powders is in the range of 20-40 m2/g depending on concentration of vapours in gas flow and cooling rate of the products. Additional calcination of nanosize particles at 800-900 deg. C improves phase composition of lithium titanates

  10. Performance of ceramic coatings on diesel engines

    International Nuclear Information System (INIS)

    MacAdam, S.; Levy, A.

    1986-01-01

    Partially stabilized zirconia ceramic thermal barrier coatings were plasma sprayed on the valve faces and tulips and the piston crowns and cylinder heads of a locomotive size diesel engine at a designated thickness of 375μm (0.015''). They were tested over a range of throttle settings for 500 hours using No. 2 diesel oil fuel. Properly applied coatings performed with no change in composition, morphology or thickness. Improperly applied coatings underwent spalling durability was dependent on quality control of the plasma spray process

  11. Layer-by-Layer Alginate and Fungal Chitosan Based Edible Coatings Applied to Fruit Bars.

    Science.gov (United States)

    Bilbao-Sainz, Cristina; Chiou, Bor-Sen; Punotai, Kaylin; Olson, Donald; Williams, Tina; Wood, Delilah; Rodov, Victor; Poverenov, Elena; McHugh, Tara

    2018-05-30

    Food waste is currently being generated at an increasing rate. One proposed solution would be to convert it to biopolymers for industrial applications. We recovered chitin from mushroom waste and converted it to chitosan to produce edible coatings. We then used layer-by-layer (LbL) electrostatic deposition of the polycation chitosan and the polyanion alginate to coat fruit bars enriched with ascorbic acid. The performance of the LbL coatings was compared with those containing single layers of fungal chitosan, animal origin chitosan and alginate. Bars containing alginate-chitosan LbL coatings showed increased ascorbic acid content, antioxidant capacity, firmness and fungal growth prevention during storage. Also, the origin of the chitosan did not affect the properties of the coatings. Mushroom stalk bases could be an alternative source for isolating chitosan with similar properties to animal-based chitosan. Also, layer-by-layer assembly is a cheap, simple method that can improve the quality and safety of fruit bars. © 2018 Institute of Food Technologists®.

  12. Retention Behaviour of Copper, Zinc, Cadmium and Lead Ions on Synthesized Zirconium Titanate Ion Exchanger

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; Abdel-Galil, E.A.; Moustafa, M.E.; Mahmoud, M.Y.

    2013-01-01

    Zr(IV) titanate as inorganic ion exchange material has been synthesized and utilized as the adsorbent for the removal of Cu 2+ , Zn 2+ , Cd 2+ and Pb 2+ ions from aqueous waste solutions. The experimental data were analyzed by Langmuir and Freundlich models of adsorption. The results suggest that the adsorption of the studied metals Cu 2+ , Zn 2+ , Cd 2+ and Pb 2+ ions on Zr(IV) titanate was favourable for the Freundlich isotherm more than Langmuir isotherm. The numerical values of 1/n for the studied metal ions were found to be smaller than the one (1/n L ) was found to be R L > 1 which confirmed that the prepared Zr(IV) titanate unfavourable the Langmuir isotherm. Based on the obtained results, practical separation experiments for the above mentioned cations on Zr(IV) titanate (ZrTi) column from aqueous waste solutions were carried out.

  13. New concepts for interplanetary balloons and blimps, particularly for Titan

    Science.gov (United States)

    Nott, J.

    This paper proposes novel approaches for balloons for planets Titan BALLUTE A balloon or blimp arriving at a planet or moon with an atmosphere might inflate falling under a parachute or after landing Neither is ideal In both cases the envelope must include qualities needed for inflation as well as those for flight A ballute BALLoon parachUTE could be used thus a ballute is like a hot air balloon with a large mouth Initially it fills by ram pressure descending through an atmosphere As proposed it would then be heated by solid propellant It would stop descending and float level with hot air lift It is now a perfect location for inflation without wind or movement through the atmosphere and away from the uncertainties of the surface A ballute could be used over several bodies in the solar system BALLOONS FOR LOW TEMPERATURES Flight in very low temperatures is also discussed Conditions are so different that it is useful to examine basic factors These apply for any planet with low temperature and weather calm enough for balloons or blimps First for terrestrial hot air balloons thermal radiation is usually the dominant way heat is lost But radiation rises with the 4th power of absolute temperature At Titan radiation will be one or two orders of magnitude smaller Also the dense atmosphere allows small balloons small temperature differences So convection is small It appears a hot air balloon can easily be heated by a radioactive source likely carried to make electricity Pinholes are not important in such a balloon

  14. Lab-on-a-Chip Instrument Development for Titan Exploration

    Science.gov (United States)

    Willis, P. A.; Greer, F.; Fisher, A.; Hodyss, R. P.; Grunthaner, F.; Jiao, H.; Mair, D.; Harrison, J.

    2009-12-01

    This contribution will describe the initial stages of a new ASTID-funded research program initiated in Fall 2009 aimed at lab-on-a-chip system development for astrobiological investigations on Titan. This technology development builds off related work at JPL and Berkeley [1-3] on the ultrasensitive compositional and chiral analysis of amino acids on Mars in order to search for signatures of past or present life. The Mars-focused instrument system utilizes a microcapillary electrophoresis (μCE) system integrated with on-chip perfluoropolyether (PFPE) membrane valves and pumps for automated liquid sample handling, on-chip derivitization of samples with fluorescent tags, dilution, and mixing with standards for data calibration. It utilizes a four-layer wafer stack design with CE channels patterned in glass, along with a PFPE membrane, a pneumatic manifold layer, and a fluidic bus layer. Three pneumatically driven on-chip diaphragm valves placed in series are used to peristaltically pump reagents, buffers, and samples to and from capillary electrophoresis electrode well positions. Electrophoretic separation occurs in the all-glass channels near the base of the structure. The Titan specific lab-on-a-chip system under development here focuses its attention on the unique organic chemistry of Titan. In order to chromatographically separate mixtures of neutral organics such as polycyclic aromatic hydrocarbons (PAHs), the Titan-specific microfluidic platform utilizes the related technique of microcapillary electrochromatography (μCEC). This technique differs from conventional μCE in that microchannels are filled with a porous stationary phase that presents surfaces upon which analyte species can adsorb/desorb. It is this additional surface interaction that enables separations of species critical to the understanding of the astrobiological potential of Titan that are not readily separated by the μCE technique. We have developed two different approaches for the integration

  15. High performance fuel electrode for a solid oxide electrochemical cell

    DEFF Research Database (Denmark)

    2013-01-01

    perovskite oxides selected from the group consisting of niobium-doped strontium titanate, vanadium-doped strontium titanate, tantalum-doped strontium titanate and mixtures thereof, thereby obtaining a porous anode backbone, (b) sintering the coated electrolyte at a high temperature, such as 1200 DEG C...

  16. Influence of the Addition of Montmorillonite in an Epoxy Powder Coating Applied on Carbon Steel

    OpenAIRE

    Piazza,Diego; Baldissera,Alessandra Fiorini; Kunst,Sandra Raquel; Rieder,Ester Schmidt; Scienza,Lisete Cristine; Ferreira,Carlos Arthur; Zattera,Ademir José

    2015-01-01

    AbstractPolymer coatings have been used for the corrosion protection of metal surfaces acting as a physical barrier against several corroding media. In spite of the good efficiency of these coatings their resistance is limited due to the presence of localized defects which give place to localized corrosion. Aiming to improve the barrier properties of these coatings this work has proposed the use of nanocomposites as powder coatings based on a standard formulation of a commercial powder varnis...

  17. Electrostatic coating technologies for food processing.

    Science.gov (United States)

    Barringer, Sheryl A; Sumonsiri, Nutsuda

    2015-01-01

    The application of electrostatics in both powder and liquid coating can improve the quality of food, such as its appearance, aroma, taste, and shelf life. Coatings can be found most commonly in the snack food industry, as well as in confectionery, bakery, meat and cheese processing. In electrostatic powder coating, the most important factors influencing coating quality are powder particle size, density, flowability, charge, and resistivity, as well as the surface properties and characteristics of the target. The most important factors during electrostatic liquid coating, also known as electrohydrodynamic coating, include applied voltage and electrical resistivity and viscosity of the liquid. A good understanding of these factors is needed for the design of optimal coating systems for food processing.

  18. Coating system to permit direct brazing of ceramics

    Science.gov (United States)

    Cadden, Charles H.; Hosking, F. Michael

    2003-01-01

    This invention relates to a method for preparing the surface of a ceramic component that enables direct brazing using a non-active braze alloy. The present invention also relates to a method for directly brazing a ceramic component to a ceramic or metal member using this method of surface preparation, and to articles produced by using this brazing method. The ceramic can be high purity alumina. The method comprises applying a first coating of a silicon-bearing oxide material (e.g. silicon dioxide or mullite (3Al.sub.2 O.sub.3.2SiO.sub.2) to the ceramic. Next, a thin coating of active metal (e.g. Ti or V) is applied. Finally, a thicker coating of a non-active metal (e.g. Au or Cu) is applied. The coatings can be applied by physical vapor deposition (PVD). Alternatively, the active and non-active metals can be co-deposited (e.g. by sputtering a target made of mullite). After all of the coatings have been applied, the ceramic can be fired at a high temperature in a non-oxidizing environment to promote diffusion, and to enhance bonding of the coatings to the substrate. After firing, the metallized ceramic component can be brazed to other components using a conventional non-active braze alloy. Alternatively, the firing and brazing steps can be combined into a single step. This process can replace the need to perform a "moly-manganese" metallization step.

  19. Transparency of the 2 μm (5000 cm-1) methane window in Titan's atmosphere and impact on retrieved surface reflectivity

    Science.gov (United States)

    Rannou, Pascal; Seignovert, Benoit; Le Mouélic, Stéphane; Sotin, Christophe

    2016-10-01

    The study of Titan properties with remote sensing relies on a good knowledge of the atmosphere properties. The in-situ observations made by Huygens combined with recent advances in the definition of methane properties enable to model and interpret observations with a very good accuracy. Thanks to these progresses, we can analyze in this work the observations made at the limb of Titan in order to retrieve information on the haze properties as its vertical profiles and its spectral behaviour along the VIMS/Cassini range (from 0.88 to 5.1 μm). However, for applications to real atmospheres, one need to account for the widening of the spectroscopic lines (e.g., Voigt profile) and apply an empirical cut-off of the far wings. In general, this is a multiplying function of the wavenumber, f(ν), applied to the Voigt profile that allows a faster decay of the wing profile beyond a given distance from the center of the line ν0 : f(ν)=1 if |ν- ν0| ≤ Δν, and f(ν)=exp(-|ν- ν0|/ σ) if |ν- ν0| > Δν. Although the 2-μm window is apparently straitforward to model, it appears that the standard cut-off parameters (that is Δν ~ 26 cm-1 and σ ~ 120 cm-1) which is used for other windows in Titan's atmosphere is not adequat for this window. Other sets of parameter must be used to reproduce Titan spectrum at 2 μm. However, there is no convergence of the results between these works and a large variety of cut-off parameters are used. Alternatively, it was found that some gas absorptions (ethane and another unknown gas) leave a signature around 2-μm and also affect the transparency in this window. In our study we make an exhaustive investigation on the cut-off parameters to determine which are the best couples of parameters to fit the 2-μm window. We also evaluated how gaseous absorptions can allow to reach a satisfactory agreement and, especially, if it allows to match observations with the standard cut-off. Finally, we investigate the impact of the different solutions

  20. The TITAN reversed-field-pinch fusion reactor study

    International Nuclear Information System (INIS)

    1990-01-01

    This paper on titan plasma engineering contains papers on the following topics: reversed-field pinch as a fusion reactor; parametric systems studies; magnetics; burning-plasma simulations; plasma transient operations; current drive; and physics issues for compact RFP reactors