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Sample records for zirconate titanate pzt

  1. A Ferroelastic Switching Model for Lead Zirconate-Titanate (PZT)

    E-print Network

    A Ferroelastic Switching Model for Lead Zirconate-Titanate (PZT) Brian L. Ball1 , Ralph C. Smith2 which characterizes the ferroelastic switching mechanisms inherent to lead zirconate-titanate (PZT and prediction of experimental PLZT data. 2 Ferroelectric and Ferroelastic Switching Mechanisms Lead zirconate-titanate

  2. Lead zirconate titanate ceramics

    SciTech Connect

    Walker, B.E. Jr.

    1986-12-02

    This patent describes a lead zirconate titanate (PZT) piezoelectric ceramic composition which, based on total composition weight, consists essentially of a solid solution of lead zirconate and lead titanate in a PbZrO/sub 3/:PbTiO/sub 3/ ratio from about 0.505:0.495 to about 0.54:0.46; a halide salt selected from the group consisting of fluorides and chlorides of alkali metal and alkaline earth elements and mixtures thereof except for francium and radium in an amount from about 0.5 to 2 weight percent; and an oxide selected from the group consisting of magnesium, barium, scandium, aluminum, lanthanum, praesodynium, neodymium, samarium, and mixtures thereof in an amount from about 0.5 to about 6 weight percent, the relative amount of oxide being from about 1 to about 4 times that of the halide.

  3. Wafer-scale fabrication of self-actuated piezoelectric nanoelectromechanical resonators based on lead zirconate titanate (PZT)

    NASA Astrophysics Data System (ADS)

    Dezest, D.; Thomas, O.; Mathieu, F.; Mazenq, L.; Soyer, C.; Costecalde, J.; Remiens, D.; Deü, J. F.; Nicu, L.

    2015-03-01

    In this paper we report an unprecedented level of integration of self-actuated nanoelectromechanical system (NEMS) resonators based on a 150?nm thick lead zirconate titanate (PZT) thin film at the wafer-scale. A top-down approach combining ultraviolet (UV) lithography with other standard planar processing technologies allows us to achieve high-throughput manufacturing. Multilayer stack cantilevers with different geometries have been implemented with measured fundamental resonant frequencies in the megahertz range and Q-factor values ranging from ~130 in air up to ~900 in a vacuum at room temperature. A refined finite element model taking into account the exact configuration of the piezoelectric stack is proposed and demonstrates the importance of considering the dependence of the beam’s cross-section upon the axial coordinate. We extensively investigate both experimentally and theoretically the transduction efficiency of the implemented piezoelectric layer and report for the first time at this integration level a piezoelectric constant of {{d}31}=15 ?fm?V-1. Finally, we discuss the current limitations to achieve piezoelectric detection.

  4. Nanoshell tubes of ferroelectric lead zirconate titanate and barium titanate Yun Luo, Izabela Szafraniak, and Nikolai D. Zakharov

    E-print Network

    Ramesh, R.

    Nanoshell tubes of ferroelectric lead zirconate titanate and barium titanate Yun Luo, Izabela templates, barium titanate and lead zirconate titanate tubes with diameters ranging from 50 nm up to several (PbZr0.52Ti0.48O3 ,PZT) and barium titanate (BaTiO3 ,BTO) nanotubes were fabricated by using

  5. Direct printing of lead zirconate titanate thin films

    E-print Network

    Bathurst, Stephen, 1980-

    2008-01-01

    Thus far, use of lead zirconate titanate (PZT) in MEMS has been limited due to the lack of process compatibility with existing MEMS manufacturing techniques. Direct printing of thin films eliminates the need for photolithographic ...

  6. Symmetries and multiferroic properties of novel room-temperature magnetoelectrics: Lead iron tantalate – lead zirconate titanate (PFT/PZT)

    DOE PAGESBeta

    Sanchez, Dilsom A.; Ortega, N.; Kumar, Ashok; Roque-Malherbe, R.; Polanco, R.; Scott, J. F.; Katiyar, Ram S.

    2011-12-01

    Mixing 60-70% lead zirconate titanate with 40-30% lead iron tantalate produces a single-phase, low-loss, room-temperature multiferroic with magnetoelectric coupling: (PbZr?.??Ti?.??O?) (1-x)- (PbFe?.?Ta?.?O?)x. The present study combines x-ray scattering, magnetic and polarization hysteresis in both phases, plus a second-order dielectric divergence (to epsilon = 6000 at 475 K for 0.4 PFT; to 4000 at 520 K for 0.3 PFT) for an unambiguous assignment as a C2v-C4v (Pmm2-P4mm) transition. The material exhibits square saturated magnetic hysteresis loops with 0.1 emu/g at 295 K and saturation polarization Pr = 25 ?C/cm², which actually increases (to 40 ?C/cm²) in the high-T tetragonal phase, representingmore »an exciting new room temperature oxide multiferroic to compete with BiFeO?. Additional transitions at high temperatures (cubic at T>1300 K) and low temperatures (rhombohedral or monoclinic at T« less

  7. Intrinsic and Extrinsic Size Effects in Fine-Grained Morphotropic-Phase-Boundary Lead Zirconate Titanate Ceramics

    E-print Network

    Cao, Wenwu

    Titanate Ceramics Clive A. Randall,* Namchul Kim, John-Paul Kucera,* Wenwu Cao, and Thomas R. Shrout The processing, electromechanical properties, and micro- structure of lead zirconate titanate (PZT) ceramics over

  8. Ferroelastic domains in lead-free barium zirconate titanate - barium calcium titanate piezoceramics

    NASA Astrophysics Data System (ADS)

    Ehmke, Matthias Claudius

    Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions. Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions.

  9. Measurement of incident position of hypervelocity particles on piezoelectric lead zirconate titanate detector

    NASA Astrophysics Data System (ADS)

    Takechi, Seiji; Onishi, Toshiyuki; Minami, Shigeyuki; Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki; Nogami, Ken-ichi; Ohashi, Hideo; Sasaki, Sho; Shibata, Hiromi; Iwai, Takeo; Grün, Eberhard; Srama, Ralf; Okada, Nagaya

    2008-04-01

    A cosmic dust detector for use onboard a satellite is currently being developed by using piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector have been studied by bombarding it with hypervelocity iron (Fe) particles supplied by a Van de Graaff accelerator. One central electrode and four peripheral electrodes were placed on the front surface of the PZT detector to measure the impact positions of the incident Fe particles. It was demonstrated that the point of impact on the PZT detector could be identified by using information on the time at which the first peak of the output signal obtained from each electrode appeared.

  10. Fundamental study of hydrothermally synthesized lead zirconate titanate polycrystals deposited on a Ti substrate during nucleation

    NASA Astrophysics Data System (ADS)

    Abe, Toshinobu; Ozeki, Seiya; Kuribayashi Kurosawa, Minoru; Takeuchi, Shinichi

    2015-07-01

    We previously fabricated a piezoelectric transducer from a lead zirconate titanate (PZT) polycrystalline film deposited on a Ti substrate by a hydrothermal synthesis method. However, the hydrothermal synthesis required a long deposition time to achieve the necessary film thickness. In this study, we confirmed that the thickness of the PZT polycrystalline film increased when the solution was stirred at 245 rpm during synthesis, and that the optimum deposition time was 5 h.

  11. Relationship between orientation factor of lead zirconate titanate nanowires and dielectric permittivity of nanocomposites

    SciTech Connect

    Tang, Haixiong E-mail: hsodano@ufl.edu; Malakooti, Mohammad H.; Sodano, Henry A. E-mail: hsodano@ufl.edu

    2013-11-25

    The relationship between the orientation of lead zirconate titanate (PZT) nanowires dispersed in nanocomposites and the resulting dielectric constants are quantified. The orientation of the PZT nanowires embedded in a polymer matrix is controlled by varying the draw ratio and subsequently quantified using Herman's Orientation Factor. Consequently, it is demonstrated that the dielectric constants of nanocomposites are improved by increasing the orientation factor of the PZT nanowires. This technique is proposed to improve the dielectric constant of the nanocomposites without the need for additional filler volume fraction since the nanocomposites are utilized in a wide range of high dielectric permittivity electronic components.

  12. Helmholtz Resonator for Lead Zirconate Titanate Acoustic Energy Harvester

    NASA Astrophysics Data System (ADS)

    Matsuda, Tomohiro; Tomii, Kazuki; Hagiwara, Saori; Miyake, Shuntaro; Hasegawa, Yuichi; Sato, Takamitsu; Kaneko, Yuta; Nishioka, Yasushiro

    2013-12-01

    Acoustic energy harvesters that function in environments where sound pressure is extremely high (~150 dB), such as in engine rooms of aircrafts, are expected to be capable of powering wireless health monitoring systems. This paper presents the power generation performances of a lead-zirconate-titanate (PZT) acoustic energy harvester with a vibrating PZT diaphragm. The diaphragm had a diameter of 2 mm, consisting of Al(0.1 ?m)/PZT(1 ?m)/Pt(0.1 ?m)/Ti(0.1 ?m)/SiO2(1.5 ?m). The harvester generated a power of 1.7×10-13 W under a sound pressure level of 110 dB at the first resonance frequency of 6.28 kHz. It was found that the generated power was increased to 6.8×10-13 W using a sound-collecting Helmholtz resonator cone with the height of 60 mm. The cone provided a Helmholtz resonance at 5.8 kHz, and the generated power increased from 3.4×10-14 W to 1.4×10-13 W at this frequency. The cone was also effective in increasing the bandwidth of the energy harvester.

  13. Simulation and calculation of the piezoelectric modulus of a lead zirconate-titanate thin film in a test microstructure

    SciTech Connect

    Amelichev, V. V.; Saikin, D. A.; Roshchin, V. M.; Silibin, M. V.

    2010-12-15

    Results of simulation of stresses in the test structure of a silicon beam and analytical calculation of piezoelectric modulus d{sub 31} of a lead zirconate-titanate (PZT) thin film arranged in the region of an elastic element are presented. The characteristics of the sensitive element of acceleration are calculated based on a PZT thin film with an inertial mass made of silicon.

  14. Optimization of PZT processing using thermal ink-jet printing

    E-print Network

    Jeon, Jessie Sungyun

    2008-01-01

    Lead zirconate titanate (PZT) has been known for its strong piezoelectric property for micro-sensors and actuators. Yet, its use in MEMS has been constrained by limitations in processing PZT with current MEMS fabrication ...

  15. Ink jet printing of PZT thin films for MEMS

    E-print Network

    Bathurst, Stephen, 1980-

    2012-01-01

    Of the readily available piezoelectric engineering materials perovskite phase lead zirconate titanate (PZT) has the strongest mechanical to electrical coupling. PZT based devices have the potential to have the highest ...

  16. Pyroelectric response of lead zirconate titanate thin films on silicon: Effect of thermal stresses

    SciTech Connect

    Kesim, M. T.; Zhang, J.; Alpay, S. P.; Trolier-McKinstry, S.; Mantese, J. V.; Whatmore, R. W.

    2013-11-28

    Ferroelectric lead zirconate titanate [Pb(Zr{sub x}Ti{sub 1-x}O){sub 3}, (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25–800?°C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042??C cm{sup ?2}?°C{sup ?1}, comparable to bulk values) at a growth temperature of 550?°C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process.

  17. Pyroelectric response of lead zirconate titanate thin films on silicon: Effect of thermal stresses

    NASA Astrophysics Data System (ADS)

    Kesim, M. T.; Zhang, J.; Trolier-McKinstry, S.; Mantese, J. V.; Whatmore, R. W.; Alpay, S. P.

    2013-11-01

    Ferroelectric lead zirconate titanate [Pb(ZrxTi1-xO)3, (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25-800 °C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042 ?C cm-2 °C-1, comparable to bulk values) at a growth temperature of 550 °C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process.

  18. Improved Performances of Acoustic Energy Harvester Fabricated Using Sol/Gel Lead Zirconate Titanate Thin Film

    NASA Astrophysics Data System (ADS)

    Kimura, Shu; Tomioka, Syungo; Iizumi, Satoshi; Tsujimoto, Kyohei; Sugou, Tomohisa; Nishioka, Yasushiro

    2011-06-01

    Energy harvesters integrable on smart sensor systems have been strongly demanded. Microelectromechanical system (MEMS) acoustic energy harvesters using the first resonance vibration of a lead zirconate titanate (PZT) thin film as a diaphragm have recently been reported. Similar acoustic energy harvesters using the third resonance of a PZT diaphragm fabricated by sol/gel PZT thin film processes exhibited improved generated power density, and it was suggested that the PZT acoustic energy harvester might be suitable for use as a possible power source for silicon integrated circuits. We present further improved power generation performances of PZT MEMS acoustic energy harvesters fabricated by improved PZT capacitor fabrication processes. The PZT acoustic energy harvester with the diaphragm diameter of 1.2 mm fabricated by a sol/gel process generated an even higher energy density of 98 µW/m2 under the sound pressure level of 100 dB (0.01 W/m2) at 16.7 kHz.

  19. Fabrication of lead zirconate titanate actuator via suspension polymerization casting

    NASA Astrophysics Data System (ADS)

    Miao, Weiguo

    2000-10-01

    The research presented herein has focused on the fabrication of a lead zirconate titanate (PZT) telescopic actuator from Suspension Polymerization Casting (SPC). Two systems were studied: an acrylamide-based hydrogel, and an acrylate-based nonaqueous system. Analytical tools such as thermomechanical analysis (TMA), differential scanning calorimetry (DSC), chemorheology, thermogravimetric analysis (TGA), and differential thermal analysis (DTA) were used to investigate the polymerization and burnout processes. The acrylamide hydrogel polymerization casting process used hydroxymethyl acrylamide (HMAM) monofunctional monomer with methylenebisacrylamide (MBAM) difunctional monomer, or used methacrylamide (MAM) as monofunctional monomer. High solid loading PZT slurries with low viscosities were obtained by optimizing the amounts of dispersant and the PZT powders. The overall activation energy of gelation was calculated to be 60--76 kJ/mol for the monomer solution, this energy was increased to 91 kJ/mol with the addition of PZT powder. The results show that the PZT powder has a retardation effect on gelation. Although several PZT tubes were made using the acrylamide-based system, the demolding and drying difficulties made this process unsuitable for building internal structures, such as the telescopic actuator. The acrylate-based system was used successfully to build telescopic actuator. Efforts were made to study the influence of composition and experimental conditions on the polymerization process. Temperature was found to have the largest impact on polymerization. To adjust the polymerization temperature and time, initiator and/or catalyst were used. PZT powder has a catalytic effect on the polymerization process. Compared with acrylamide systems, acrylate provided a strong polymer network to support the ceramic green body. This high strength is beneficial for the demolding process, but it can easily cause cracks during the burnout process. To solve the burnout issue, non-reactive decalin was used as a solvent to lower the stress inside the green body. The addition of decalin has no large impact on the polymerization process. With 15 wt% decalin in the monomer solution, the burnout process was successfully solved. The burnout process was monitored by TGA/DTA and TMA. A 51 vol% PZT filled acrylate slurry was cast into a mold made by Stereolithography (SLA), and after curing, the telescopic actuator was removed from the mold. This indirect SLA method provides an efficient way to build ceramic parts. PZT samples were sintered at 1275°C for 4 hours, with density over 98%. SEM analysis showed the sample made by SPC has a uniform microstructure, which may be beneficial to the electric properties. The sample made by polymerization has a d33 value about 680 pm/V, which is better than the literature value (580 pm/V). The electric tests showed this telescopic actuator produced a maximum deflection of 24.7 mum at 250 kV/m, in line with theoretical calculations. Compared with actuators made by other methods, the actuator made by SPC provides a comparable structural factor (187.5). The distortion in actuators is caused by fabrication and sintering.

  20. Effects of electric field and biaxial flexure on the failure of poled lead zirconate titanate.

    PubMed

    Wang, Hong; Wereszczak, Andrew A

    2008-12-01

    Reliable design of lead zirconate titanate (PZT) piezo stack actuators demands that several issues, including electromechanical coupling and ceramic strength-size scaling, be scrutinized. This study addresses those through the use of ball-on-ring (BoR) biaxial flexure strength tests of a PZT piezoelectric material that is concurrently subjected to an electric field. The Weibull strength distributions and fracture surfaces were examined. The mechanical failures were further analyzed in terms of internal stress, energy release rate, and domain-switching toughening. Both the sign and the magnitude of an electric field had a significant effect on the strength of poled PZT within the tested range. A surface flaw type with an average depth of around 18 microm was identified to be the strength limiter and responsible for the failure of the tested PZT under both mechanical and electromechanical loadings. With a value of 0.74 MPa.m(1/2) in the absence of electric field, the fracture toughness of the poled PZT was affected by an applied electric field just as the strength was affected. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators. PMID:19126481

  1. Development of a stress sensor based on the piezoelectric lead zirconate titanate for impact stress measurement

    NASA Astrophysics Data System (ADS)

    Liu, Yiming; Xu, Bin; Li, Lifei; Li, Bing

    2011-11-01

    The measurement of stress of concrete structures under impact loading and other strong dynamic loadings is crucial for the monitoring of health and damage detection. Due to its main advantages including availability, extremely high rigidity, high natural frequency, wide measuring range, high stability, high reproducibility, high linearity and wide operating temperature range, piezoelectric (Lead Zirconate Titanate, PZT) ceramic materials has been a widely used smart material for both sensing and actuation for monitoring and control in engineering structures. In this paper, a kind of stress sensor based on piezoelectric ceramics for impact stress measuring of concrete structures is developed. Because the PZT is fragile, in order to employ it for the health monitoring of concrete structures, special handling and treatment should be taken to protect the PZT and to make it survive and work properly in concrete. The commercially available PZT patch with lead wires is first applied with an insulation coating to prevent water and moisture damage, and then is packaged by jacketing it by two small precasted cylinder concrete blocks with enough strength to form a smart aggregate (SA). The employed PZT patch has a dimension of 10mm x 10mm x 0.3mm. In order to calibrate the PZT based stress sensor for impact stress measuring, a dropping hammer was designed and calibration test on the sensitivity of the proposed transducer was carried out with an industry charge amplifier. The voltage output of the stress sensor and the impact force under different free falling heights and impact mass were recorded with a high sampling rate data acquisition system. Based on the test measurements, the sensibility of the PZT based stress sensor was determined. Results show that the output of the PZT based stress sensor is proportional to the stress level and the repeatability of the measurement is very good. The self-made piezoelectric stress sensor can be easily embedded in concrete and provide reliable stress sensing under dynamic loadings.

  2. Development of a stress sensor based on the piezoelectric lead zirconate titanate for impact stress measurement

    NASA Astrophysics Data System (ADS)

    Liu, Yiming; Xu, Bin; Li, Lifei; Li, Bing

    2012-04-01

    The measurement of stress of concrete structures under impact loading and other strong dynamic loadings is crucial for the monitoring of health and damage detection. Due to its main advantages including availability, extremely high rigidity, high natural frequency, wide measuring range, high stability, high reproducibility, high linearity and wide operating temperature range, piezoelectric (Lead Zirconate Titanate, PZT) ceramic materials has been a widely used smart material for both sensing and actuation for monitoring and control in engineering structures. In this paper, a kind of stress sensor based on piezoelectric ceramics for impact stress measuring of concrete structures is developed. Because the PZT is fragile, in order to employ it for the health monitoring of concrete structures, special handling and treatment should be taken to protect the PZT and to make it survive and work properly in concrete. The commercially available PZT patch with lead wires is first applied with an insulation coating to prevent water and moisture damage, and then is packaged by jacketing it by two small precasted cylinder concrete blocks with enough strength to form a smart aggregate (SA). The employed PZT patch has a dimension of 10mm x 10mm x 0.3mm. In order to calibrate the PZT based stress sensor for impact stress measuring, a dropping hammer was designed and calibration test on the sensitivity of the proposed transducer was carried out with an industry charge amplifier. The voltage output of the stress sensor and the impact force under different free falling heights and impact mass were recorded with a high sampling rate data acquisition system. Based on the test measurements, the sensibility of the PZT based stress sensor was determined. Results show that the output of the PZT based stress sensor is proportional to the stress level and the repeatability of the measurement is very good. The self-made piezoelectric stress sensor can be easily embedded in concrete and provide reliable stress sensing under dynamic loadings.

  3. Structural heterogeneity and diffuse scattering in morphotropic lead zirconate-titanate single crystals.

    PubMed

    Burkovsky, R G; Bronwald, Yu A; Filimonov, A V; Rudskoy, A I; Chernyshov, D; Bosak, A; Hlinka, J; Long, X; Ye, Z-G; Vakhrushev, S B

    2012-08-31

    Complementary diffuse and inelastic synchrotron x-ray scattering measurements of lead zirconate-titanate single crystals with composition near the morphotropic phase boundary (x=0.475) are reported. In the temperature range 293 KPZT at its morphotropic phase boundary is essentially structurally inhomogeneous. PMID:23002887

  4. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    SciTech Connect

    Wang, Hong Lee, Sung-Min; Wang, James L.; Lin, Hua-Tay

    2014-12-21

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0?kV/mm, 100?Hz to 10{sup 8} cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications, such as piezoelectric fuel injectors in heavy-duty diesel engines.

  5. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    SciTech Connect

    Wang, Hong; Lee, Sung Min; Wang, James L; Lin, Hua-Tay

    2014-01-01

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 10^8 cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications such as piezoelectric fuel injectors in heavy-duty diesel engines.

  6. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Lee, Sung-Min; Wang, James L.; Lin, Hua-Tay

    2014-12-01

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 108 cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications, such as piezoelectric fuel injectors in heavy-duty diesel engines.

  7. High Quality Factor Silicon Cantilever Transduced by Piezoelectric Lead Zirconate Titanate Film for Mass Sensing Applications

    NASA Astrophysics Data System (ADS)

    Lu, Jian; Ikehara, Tsuyoshi; Zhang, Yi; Mihara, Takashi; Itoh, Toshihiro; Maeda, Ryutaro

    2007-12-01

    In this paper, we present a single-crystal silicon cantilever integrated with piezoelectric lead zirconate titanate (PZT) film as both an actuator and a sensor for resonant-based mass sensing applications. The pattern size of the PZT film was restricted to the fixed end of the cantilever to suppress intrinsic energy loss from the PZT film and multi layered structure. The energy dissipation mechanism of the cantilever was discussed. The mechanical quality factor (Q-factor) and sensitivity dependence on the cantilever’s geometry were investigated. It was found that the Q-factor and sensitivity of the cantilever can be markedly improved by partially covering the cantilever with the PZT film. Under atmospheric pressure, excellent Q-factor of 808 was achieved by a 30-?m-wide 100-?m-long cantilever at fundamental resonant mode. Under reduced pressure, the proposed cantilever exhibits Q-factor several times greater than that of our previous reported fully PZT-covered cantilever. Moreover, high-mode vibration was successfully demonstrated using the proposed structure for the pursuit of higher mass-detection sensitivity.

  8. Lead-Zirconate-Titanate Acoustic Energy Harvesters with Dual Top Electrodes

    NASA Astrophysics Data System (ADS)

    Tomioka, Shungo; Kimura, Shu; Tsujimoto, Kyohei; Iizumi, Satoshi; Uchida, Yusuke; Tomii, Kazuki; Matsuda, Tomohiro; Nishioka, Yasushiro

    2011-09-01

    In this paper, we present the power generation performances of a lead-zirconate-titanate (PZT) microelectromechanical system (MEMS) acoustic energy harvester having dual top electrodes to utilize the different polarizations of charges on the surface of a vibrating PZT diaphragm at first resonance. The PZT acoustic energy harvester had a diaphragm with a diameter of 2 mm consisting of Al (0.1 µm)/PZT (1 µm)/Pt (0.1 µm)/Ti (0.1 µm)/SiO2 (1.5 µm), and the diaphragm vibrations were excited by sound pressure. The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of 5.28×10-11 W, and the central energy harvester generated a power of 4.25×10-11 W at a sound pressure level of 100 dB (0.01 W/m2) at 4.92 kHz. Thus, nearly 80% of the total power of the energy harvesters can be increased by utilizing the polarization at the central part of the diaphragm, which was usually not considered when only the peripheral part of the diaphragm was utilized.

  9. Hydrogen diffusion in Lead Zirconate Titanate and Barium Titanate

    SciTech Connect

    Alvine, Kyle J.; Vijayakumar, M.; Bowden, Mark E.; Schemer-Kohrn, Alan L.; Pitman, Stan G.

    2012-08-28

    Hydrogen is a potential clean-burning, next-generation fuel for vehicle and stationary power. Unfortunately, hydrogen is also well known to have serious materials compatibility issues in metals, polymers, and ceramics. Piezoelectric actuator materials proposed for low-cost, high efficiency high-pressure hydrogen internal combustion engines (HICE) are known to degrade rapidly in hydrogen. This limits their potential use and poses challenges for HICE. Hydrogen-induced degradation of piezoelectrics is also an issue for low-pressure hydrogen passivation in ferroelectric random access memory. Currently, there is a lack of data in the literature on hydrogen species diffusion in piezoelectrics in the temperature range appropriate for the HICE as charged via a gaseous route. We present 1HNMR quantification of the local hydrogen species diffusion within lead zirconate titanate and barium titanate on samples charged by exposure to high-pressure gaseous hydrogen ?32?MPa. Results are discussed in context of theoretically predicted interstitial hydrogen lattice sites and aqueous charging experiments from existing literature.

  10. Biaxial Flexural Strength of Poled Lead Zirconate Titanate under High Electric Field with Extended Field Range

    SciTech Connect

    Zhang, Kewei; Zeng, Fan W; Wang, Hong; Lin, Hua-Tay

    2013-01-01

    In the present work, as-received poled lead zirconate titanate, or PZT 5A, was examined using ball-on-ring (BoR) mechanical testing coupled with an electric field. Electric fields in the range of 4Ec (Ec, coercive field) with controlled loading paths were applied, and mechanical tests at a substantial number of characteristic electric field levels were conducted. Commercial electronic liquid FC-40 was used to prevent the setup from dielectric breakdown under a high electric field. Weibull strength distribution was used to interpret the mechanical strength data. The data showed that the strength levels of the PZT-5A tested under OC (open circuit) in air and in FC-40 were almost the same. It was further revealed that , for the studied cases, the effect of loading history on the biaxial flexural strength of the PZT was significant in -Ec, but not in OC or zero field as well as 4Ec . An asymmetry V curve was observed for the characteristic strength-electric field graph, and the bottom of V curve was located near the negative coercive field. Microscopy analysis showed that surface-located volume-distributed flaws were the strength limiter and responsible for the failure of the tested PZT under electromechanical loadings.

  11. Thickness dependence of structural and electrical properties in epitaxial lead zirconate titanate films

    E-print Network

    Alpay, S. Pamir

    Thickness dependence of structural and electrical properties in epitaxial lead zirconate titanate of misfit strain on the microstructure and properties of ferroelectric lead zirconate titanate thin films and subsequently control it. The earliest studies on the switching behavior of lead zirconate titanate thin films

  12. Transverse piezoelectric coefficient measurement of flexible lead zirconate titanate thin films

    NASA Astrophysics Data System (ADS)

    Dufay, T.; Guiffard, B.; Thomas, J.-C.; Seveno, R.

    2015-05-01

    Highly flexible lead zirconate titanate, Pb(Zr,Ti)O3 (PZT), thin films have been realized by modified sol-gel process. The transverse piezoelectric coefficient d31 was determined from the tip displacement of bending-mode actuators made of PZT cantilever deposited onto bare or RuO2 coated aluminium substrate (16 ?m thick). The influence of the thickness of ruthenium dioxide RuO2 and PZT layers was investigated for Pb(Zr0.57Ti0.43)O3. The modification of Zr/Ti ratio from 40/60 to 60/40 was done for 3 ?m thick PZT thin films onto aluminium (Al) and Al/RuO2 substrates. A laser vibrometer was used to measure the beam displacement under controlled electric field. The experimental results were fitted in order to find the piezoelectric coefficient. Very large tip deflections of about 1 mm under low voltage (˜8 V) were measured for every cantilevers at the resonance frequency (˜180 Hz). For a given Zr/Ti ratio of 58/42, it was found that the addition of a 40 nm thick RuO2 interfacial layer between the aluminium substrate and the PZT layer induces a remarkable increase of the d31 coefficient by a factor of 2.7, thus corresponding to a maximal d31 value of 33 pC/N. These results make the recently developed PZT/Al thin films very attractive for both low frequency bending mode actuating applications and vibrating energy harvesting.

  13. Microwave emission from lead zirconate titanate induced by impulsive mechanical load

    NASA Astrophysics Data System (ADS)

    Aman, A.; Majcherek, S.; Hirsch, S.; Schmidt, B.

    2015-10-01

    This paper focuses on microwave emission from Lead zirconate titanate Pb [ZrxTi1-x] O3 (PZT) induced by mechanical stressing. The mechanical stress was initiated by impact of a sharp tungsten indenter on the upper surface of PZT ceramic. The sequences of microwave and current impulses, which flew from indenter to electric ground, were detected simultaneously. The voltage between the upper and lower surface of ceramic was measured to obtain the behavior of mechanical force acting on ceramic during the impact. It was found that the amplitude, form, and frequency of measured microwave impulses were different by compression and restitution phase of impact. Two different mechanisms of electron emission, responsible for microwave impulse generation, were proposed based on the dissimilar impulse behavior. The field emission from tungsten indenter is dominant during compression, whereas ferroemission dominates during restitution phase. Indeed, it was observed that the direction of the current flow, i.e., sign of current impulses is changed by transitions from compression to restitution phase of impact. The observed dissimilar behavior of microwave impulses, caused by increasing and decreasing applied force, can be used to calculate the contact time and behavior of mechanical force during mechanical impact on ceramic surface. It is shown that the generation of microwave impulses exhibits high reproducibility, impulse intensity, a low damping factor, and high mechanical failure resistance. Based on these microwave emission properties of PZT, the development of new type of stress sensor with spatial resolution of few microns becomes possible.

  14. Strength Properties of Aged Poled Lead Zirconate Titanate Subjected to Electromechanical Loadings

    SciTech Connect

    Zhang, Kewei; Zeng, Fan W; Wang, Hong; Lin, Hua-Tay

    2012-01-01

    Electric field and aging time are two important factors that affect the mechanical strength and long-term reliability of lead zirconate titanate or PZT actuators. In the present work, a commercial PZT-5A aged four years was examined using ball-on-ring (BoR) mechanical testing under coupled electric fields. The electric field range of -3E{sub c} to +3E{sub c} (E{sub c}, coercive electric field) was studied (i.e., -3E{sub c}, -E{sub c}, 0, +E{sub c}, +2E{sub c}, and +3E{sub c}) with a controlled electric loading path. A Weibull distribution was used to interpret the mechanical strength data. With an electric field preloaded from 0 to -3E{sub c}, it was found that subsequent increases in the electric field resulted in an asymmetrical V-shaped curve of mechanical strength against the electric field. The bottom of the V curve was located near the zero electric field level. Microscopy analysis showed that pores were the strength limiter for the tested PZT under electromechanical loadings.

  15. A statistical model approximation for perovskite solid-solutions: A Raman study of lead-zirconate-titanate single crystal

    NASA Astrophysics Data System (ADS)

    Frantti, J.; Fujioka, Y.; Puretzky, A.; Xie, Y.; Ye, Z.-G.; Glazer, A. M.

    2013-05-01

    Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B-cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.

  16. Piezoelectric and Dielectric Performance of Poled Lead Zirconate Titanate Subjected to Electric Cyclic Fatigue

    SciTech Connect

    Wang, Hong; Matsunaga, Tadashi; Lin, Hua-Tay; Mottern, Alexander M; Wereszczak, Andrew A

    2012-01-01

    Poled lead zirconate titanate (PZT) material as a single-layer plate was tested using piezodilatometer under electric cyclic loading in both unipolar and bipolar modes. Their responses were evaluated using unipolar and bipolar measurements on the same setup. Mechanical strain and charge density or polarization loops exhibited various variations when the material was cycled to more than 10^8 cycles. Important quantities including loop amplitude, hysteresis, switchable polarization, coercive field have been characterized accordingly under corresponding measurement conditions. At the same time, offset polarization and bias electric field of the material were observed to be changed and the trend was found to be related to the measurement condition also. Finally, the piezoelectric and dielectric coefficients were analyzed and their implications to the application of interest have been discussed.

  17. Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling

    SciTech Connect

    Zeng, Fan W; Wang, Hong; Lin, Hua-Tay

    2013-01-01

    Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 10^5 to 7 10^5 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 10^8 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. A scanning acoustic microscope also was employed as a nondestructive tool to detect the presence of defects. Failed plates were subsequently sectioned, and the extensive cracks and porous regions were observed to be across the PZT layers. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to monitor the behavior of PZT stacks.

  18. EPDM composite membranes modified with cerium doped lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Zaharescu, T.; Dumitru, A.; Lungulescu, M. E.; Velciu, G.

    2016-01-01

    This study was performed on ?-irradiated ethylene-propylene diene terpolymer (EPDM) loaded with lead zirconate titanate. The inorganic phase has a perovskite structure with general formula Pb(Zr0.65-xCexTi0.35)O3. The three composites with different Ce dopant concentrations revealed the stabilization activity of filler against oxidation proved by chemiluminescence investigation in respect to pristine polymer. The presence of cerium low concentrations in the solid lead zirconate titanate nanoparticles causes significant slowing of oxidation rate during radiation exposure. The improvement in the stabilization feature of filler is correlated with the existence of traps, whose interaction with free radicals assumes medium energy due to their convenient depth.

  19. A circular array transducer for photoacoustic imaging by using piezoelectric single crystal lead magnesium niobate-lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Cao, Yonggang; Ha, Kanglyeol; Kim, Moojoon; Kang, Hyunwook; Oh, Jung-Hwan; Kim, Jungsoon

    2015-07-01

    The ultrasound transducers of which center frequencies are lower than 10 MHz are commonly used in low frequency photoacoustic (PA) imaging systems. However, the improvement of their sensitivity is still needed to detect weak PA signals. In this study, a circular array transducer was constructed by using 120 needle hydrophones made of piezoelectric single crystal lead magnesium niobate-lead zirconate titanate (PMN-PZT). The needle hydrophone was designed to have high sensitivity and wide bandwidth through the Krimtholz-Leedom-Matthaei (KLM) simulation of receiving impulse response. The sensitivity of the fabricated PMN-PZT hydrophone was compared with a commercial poly(vinylidene fluoride) (PVDF) needle hydrophone. The usefulness of the circular array transducer was demonstrated by applying it to a PA system for obtaining images.

  20. Design and modeling of a PZT thin film based piezoelectric micromachined ultrasonic transducer (PMUT)

    E-print Network

    Smyth, Katherine Marie

    2012-01-01

    The design and modelling framework for a piezoelectric micromachined ultrasonic transducer (PMUT) based on the piezoelectric thin film deposition of lead zirconate titanate (PZT) is defined. Through high frequency vibration ...

  1. The fabrication of silicon-based PZT microstructures using an aerosol deposition method

    NASA Astrophysics Data System (ADS)

    Wang, Xuan-Yu; Lee, Chi-Yuan; Hu, Yuh-Chung; Shih, Wen-Pin; Lee, Chih-Cheng; Huang, Jung-Tang; Chang, Pei-Zen

    2008-05-01

    This paper presents a series of processes for fabricating lead-zirconate-titanate (PZT) microstructures on a silicon substrate. An aerosol deposition method was used to deposit PZT thick film at room temperature. The low temperature deposition enabled a special lift-off process for patterning thick PZT films using a THB-151N photoresist. The milling rate of THB-151N by PZT particles was found to be the same as the PZT deposition rate of 5 ?m h-1. Using this patterning technique, complex configurations of PZT microstructures have been demonstrated. Suspended multi-layer PZT microstructures have also been realized in this work.

  2. Strontium doped lead zirconate titanate ceramics: study of calcination and sintering process to improve piezo effect.

    PubMed

    Khalid, Muhammad; Shoaib, Muhammad; Khan, Amir Azam

    2011-06-01

    Perovskite crystal structure is found in many ionic solids like CaTiO3, BaTiO3 and Lead Zirconate Titanates (PZT). In this structure off-center position of cations in oxygen octahedral causes polarization and produces direct and indirect piezoelectric responses in ceramic materials that are suitable for many ultrasonic applications. In the present study 9% Sr doped PZT ceramics were prepared and their dielectric and piezoelectric properties measured. X ray Diffraction (XRD) analysis of calcined powders demonstrated a decrease in the PbO content during the calcination stage at 850 degrees C. This was counterbalanced by adding excess PbO at the time of preparation of mixtures. Sintering was carried out at 1200 degrees C for 2 hours in lead rich atmosphere. The properties achieved were Dielectric Constant (K) = 1440, Tangent Loss (Tan delta) = 0.0062, Charge Coefficient (d33) = 335 pC/N and density = 7.55 g/cm3. SEM analysis of sintered samples demonstrated that grain size was 2-3 microm with clean grain boundaries and no large size porosity observed. XRD analysis of sintered pellets exhibited that material prepared was free of any precipitated phase usually harmful for the piezo effect. PMID:21770202

  3. The extrinsic nature of nonlinear behavior observed in lead zirconate titanate ferroelectric ceramic

    E-print Network

    Cao, Wenwu

    to include the nonlinear contributions. With only 90" wall vibration being considered, the theory leadsThe extrinsic nature of nonlinear behavior observed in lead zirconate titanate ferroelectric February 1991) The nonlinear electric and electromechanical responses of lead zirconate titanate Pb

  4. Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting.

    PubMed

    Qin, Lifeng; Sun, Yingying; Wang, Qing-Ming; Zhong, Youliang; Ou, Ming; Jiang, Zhishui; Tian, Wei

    2012-12-01

    In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ?(T)(33)/?(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application. PMID:23221230

  5. Effect of Hydrogen Anneals on Niobium-Doped Lead Zirconate Titanate Capacitors with Lanthanum Strontium Cobalt Oxide/Platinum Electrodes

    NASA Astrophysics Data System (ADS)

    Evans, Joe; Jr., Jr.; Boyer, Leonard; Velasquez, Geri; Ramesh, Ramamoorthy; Aggarwal, Sanjeev; Keramidas, Vassillis

    1999-09-01

    Ferroelectric capacitors, being oxide ceramics, are very sensitive to the effects of hydrogen environments at elevated temperatures [H. Ashida et al..: Integr. Ferroelectr. 21 (1998) 97]. After a capacitor has been exposed directly to a annealing hydrogen environment at low hydrogen partial pressures, the electrical properties of the device can deteriorate and leakage currents can increase. At higher hydrogen concentration gradients, such as the formidable forming gas annealing, physical failure of the inter-layer dielectric (ILD) and/or top electrode adhesion can occur. The authors have examined various structural approaches to mitigate the effects of hydrogen damage on integrated ferroelectric lead zirconate titanate (PZT) capacitors. These approaches, including the use of a titanium dioxide barrier layer above the PZT to impede the reducing effect of hydrogen on the ceramic and the use of electrode layers other than platinum to eliminate the generation of free hydrogen ions by catalyst action [S. Aggarwal et al..: Appl. Phys. Lett. 73 (1998) 1973]. The authors have found that niobium-doped PZT capacitors using LSCO/platinum electrodes passivated with titanium dioxide will recover from 1% forming gas annealing within 30 minutes at 450°C in nitrogen.

  6. In situ, in-liquid, all-electrical detection of Salmonella typhimurium using lead titanate zirconate/gold-coated glass cantilevers at any dipping depth.

    PubMed

    Zhu, Qing; Shih, Wan Y; Shih, Wei-Heng

    2007-06-15

    Most biosensing techniques are indirect, slow, and require labeling. Even though silicon-based microcantilever sensors are sensitive and label-free, they are not suitable for in-liquid detection. More recently lead zirconate titanate (PZT) thin-film-based microcantilevers are shown to be sensitive and in situ. However, they require microfabrication and must be electrically insulated. In this study, we show that highly sensitive, in situ, Salmonella typhimurium detection can be achieved at 90% relative humidity using a lead zirconate titanate (PZT)/gold-coated glass cantilever 0.7 mm long with a non-piezoelectric 2.7 mm long gold-coated glass tip by partially dipping the gold-coated glass tip in the suspension at any depth without electrically insulating the PZT. In particular, we showed that at 90% relative humidity and with a dipping depth larger than 0.8mm the PZT/gold-coated glass cantilever showed virtually no background resonance frequency up-shift due to water evaporation and exhibited a mass detection sensitivity of Deltam/Deltaf=-5 x 10(-11)g/Hz. The concentration sensitivities of this PZT/gold-coated glass cantilever were 1 x 10(3) and 500 cells/ml in 2 ml of liquid with a 1 and 1.5mm dipping depth, respectively, both more than two orders of magnitude lower than the infectious dose and more than one order of magnitude lower than the detection limit of a commercial Raptor sensor. PMID:17387007

  7. Luminescence studies of perovskite structured titanates: A review

    NASA Astrophysics Data System (ADS)

    Nag Bhargavi, G.; Khare, Ayush

    2015-06-01

    Apart from widely known dielectric and ferroelectric properties, the perovskite type materials also constitute a class of materials, which are recently investigated for their optical properties. These materials are being used for fabrication of various microelectronics and optoelectronic devices. Photoluminescence (PL), mechanoluminescence (ML) and thermoluminescence (TL) are such phenomena offering numerous applications in different fields like electro-optics, flat panel displays, LED technology, sensors, dynamic visualization etc. This paper briefly reviews the status and new progress in luminescence studies of ferroelectric materials like barium titanate (BT), barium zirconate titanate (BZT), calcium titanate (CT), calcium zirconate titanate (CZT), lead titanate (PT), lead zirconate titanate (PZT), etc., prepared through various methods.

  8. Ferroelectric PZT RF MEMS Resonators Jeffrey S. Pulskamp, Sarah S. Bedair, Ronald G.

    E-print Network

    Afshari, Ehsan

    Ferroelectric PZT RF MEMS Resonators Jeffrey S. Pulskamp, Sarah S. Bedair, Ronald G. Polcawich- piezoelectric lead zirconate titanate (PZT) RF MEMS resonators. Several research topics are introduced including (~117dB) parallel resonant mode with DC bias tunable rejection, a MEMS support design for the mitigation

  9. Converse mode piezoelectric coefficient for lead zirconate titanate thin film with interdigitated electrode

    NASA Astrophysics Data System (ADS)

    Chidambaram, N.; Balma, D.; Nigon, R.; Mazzalai, A.; Matloub, R.; Sandu, C. S.; Muralt, P.

    2015-04-01

    The use of interdigitated electrodes (IDEs) in conjunction with ferroelectric thin films shows many attractive features for piezoelectric MEMS applications. In this work, growth of {1?0?0}-textured lead zirconate titanate (PZT) thin films was achieved on insulating MgO buffered, oxidized silicon substrates. IDEs were fabricated by lift-off techniques and cantilevers were formed by dicing. The deflection upon application of a sweeping voltage was measured as large signal response in parallel to the ferroelectric polarization (PV loop). Likewise, the small signal piezoelectric response was measured in parallel to the capacitance-voltage (CV) measurement. In this way, a complete picture of the ferroelectric-piezoelectric element was obtained. From the deflection, the in-plane piezoelectric stress in the PZT thin film was derived and, from this, the effective piezoelectric coefficients. For the latter, two types were defined: an engineering type corresponding to the average value along the IDE, which can directly be compared to coefficient of a parallel plate electrode (PPE) capacitor and a second one that approximately yields the idealized coefficient governing between the electrode fingers. The IDE structures were experimentally compared with PPE structures of identical film thickness. The resulting coefficients were of opposite sign, as expected. In spite of a much better polarization loop, the IDE device showed a lower average piezoelectric stress. The estimated peak value between the fingers was about the same as in the PPE device, corresponding to about 20 C m-2. Nevertheless, the result is very promising for cases where compressive piezoelectric stresses are required and for preventing cracking due to large piezoelectric tensile stresses in PPE systems.

  10. Formation and properties of porous films of lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Seregin, D. S.; Vorotilov, K. A.; Sigov, A. S.; Zubkova, E. N.; Abdullaev, D. A.; Kotova, N. M.; Vishnevskiy, A. S.

    2015-03-01

    The processes of formation and the properties of porous ceramic lead zirconate titanate films have been considered. The porous structure formed by thermal destruction of polyvinylpyrrolidone (PVP) with the molecular weight 29000 makes it possible to increase the cracking-free film thickness (by a factor of approximately two for one deposition at 20 wt % PVP; in this case, the volume porosity is 33%). An increase in the porosity decreases the permittivity ?; at 20 wt % PVP, ? = 432-456 depending on the film thickness. These values are less than those in nonporous films by a factor of more than two. An increase in the porosity is accompanied by an increase in the remanent polarization in the films. However, the hysteresis loop shape changes in the region of saturation polarization.

  11. Vibration Characteristics of Piezoelectric Lead Zirconate Titanate by Fluid Flow in Intravascular Oxygenator

    NASA Astrophysics Data System (ADS)

    Kim, Gi?Beum; Hong, Chul?Un; Kwon, Tae?Kyu

    2006-04-01

    In this paper, we describe the enhancement in oxygen transfer rate in hollow-fiber-membrane (HFM) modules using a plumbum piezoelectric lead zirconate titanate (PZT) actuator and a piezoelectric poly vinylidene fluoride (PVDF) sensor. We developed a vibrating intravascular lung assist device (VIVLAD) for patients having chronic respiratory problems and performed experiments on hydrodynamic flow through a bundle of sinusoidal vibrating hollow fibers. These modules were used to provide some insight into how wall vibrations might enhance the performance of an intravascular lung assist device. The experimental design and procedure are then applied to the fabrication of a device used to assess the effectiveness of membrane vibrations. The test section was a cylindrical duct with an inner diameter of 30 mm. The flow rate was controlled by a pump and monitored by a built-in flowmeter. The vibration apparatus was composed of a piezovibrator, a function generator, and a power amplifier. The direction of vibration was radial to the fluid flow. Gas flow rates of up to 6 L/min through 120-cm-long hollow fibers were achieved by exciting the piezovibrator. The time and frequency responses of PVDF sensors were investigated through various frequencies in VIVLAD. In these devices, the flow of blood and the source of oxygen were separated by a semipermeable membrane that allows oxygen and carbon dioxide to diffuse into and out of the fluid, respectively. Results of the experiments have shown that a vibrating intravascular lung assist device performs effectively.

  12. Fabrication and modeling of bismuth titanate-PZT ceramic transducers for high temperature applications

    NASA Astrophysics Data System (ADS)

    Reinhardt, B.; Searfass, C.; Cyphers, R.; Sinding, K.; Pheil, C.; Tittmann, B.

    2013-01-01

    Utilization of a spray-on deposition technique of ferroelectric bismuth titanate (Bi4Ti3O12) composites has a competitive advantage to standard ultrasonic transducers. These can conform to curved surfaces, can operate at high temperature (Curie-Weiss temperature 685 °C) and are mechanically well-coupled to a substrate. However, an issue with many high temperature transducers such as bismuth titanate ceramics is that they have relatively low transduction efficiency, i.e. d33 is about 12-14 pC/F in Bi4Ti3O12 versus 650 pC/F in PZT-5H. It is a common conception that high-temperature capability comes at the cost of electro-mechanical coupling. It will be shown that the high temperature capability of bismuth-titanate-PZT composite transducers using the spray-on deposition technique previously developed, improves the electro-mechanical coupling while maintaining the high temperature performance and mechanical coupling. This material could provide advantages in harsh environments where high signal-to-noise ratios are needed.

  13. Electrical Properties and Microstructure of Low-Temperature-Crystallized Lead Zirconate Titanate Thin Films Prepared by 2.45 GHz Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Zhan Jie; Otsuka, Yuka; Cao, Zhiping; Kokawa, Hiroyuki

    2009-09-01

    Lead zirconate titanate (PZT) thin films were coated on Pt/Ti/SiO2/Si substrates by a sol-gel method and then crystallized at 490 °C using the magnetic field of 2.45 GHz microwave irradiation. The crystalline phases and microstructures as well as the electrical properties of the PZT thin films were investigated. X-ray diffraction analysis indicated that the films were crystallized well into the perovskite phase. Scanning electron microscopy showed that the PZT films had a typical rosette structure, which consisted of large round grains on a matrix of fine grains. A transmission electron microscopy (TEM) study revealed that the fine grains were also mainly crystallized into the perovskite phase. The average remanent polarization and coercive field of the PZT films were approximately 21 ?C/cm2 and 92 kV/cm, respectively, whereas the dielectric constant and loss value measured at 1 kHz were approximately 510 and 0.07, respectively.

  14. Electrical Properties and Microstructure of Low-Temperature-Crystallized Lead Zirconate Titanate Thin Films Prepared by 2.45 GHz Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Jie Wang, Zhan; Otsuka, Yuka; Cao, Zhiping; Kokawa, Hiroyuki

    2009-09-01

    Lead zirconate titanate (PZT) thin films were coated on Pt/Ti/SiO2/Si substrates by a sol-gel method and then crystallized at 490 °C using the magnetic field of 2.45 GHz microwave irradiation. The crystalline phases and microstructures as well as the electrical properties of the PZT thin films were investigated. X-ray diffraction analysis indicated that the films were crystallized well into the perovskite phase. Scanning electron microscopy showed that the PZT films had a typical rosette structure, which consisted of large round grains on a matrix of fine grains. A transmission electron microscopy (TEM) study revealed that the fine grains were also mainly crystallized into the perovskite phase. The average remanent polarization and coercive field of the PZT films were approximately 21 µC/cm2 and 92 kV/cm, respectively, whereas the dielectric constant and loss value measured at 1 kHz were approximately 510 and 0.07, respectively.

  15. Evaluation of antibacterial properties of Barium Zirconate Titanate (BZT) nanoparticle

    PubMed Central

    Mohseni, Simin; Aghayan, Mahdi; Ghorani-Azam, Adel; Behdani, Mohammad; Asoodeh, Ahmad

    2014-01-01

    So far, the antibacterial activity of some organic and inorganic compounds has been studied. Barium zirconate titanate [Ba(ZrxTi1-x)O3] (x = 0.05) nanoparticle is an example of inorganic materials. In vitro studies have provided evidence for the antibacterial activity of this nanoparticle. In the current study, the nano-powder was synthesized by sol-gel method. X-ray diffraction showed that the powder was single-phase and had a perovskite structure at the calcination temperature of 1000 °C. Antibacterial activity of the desired nanoparticle was assessed on two gram-positive (Staphylococcus aureus PTCC1431 and Micrococcus luteus PTCC1625) and two gram-negative (Escherichia coli HP101BA 7601c and clinically isolated Klebsiella pneumoniae) bacteria according to Radial Diffusion Assay (RDA). The results showed that the antibacterial activity of BZT nano-powder on both gram-positive and gram-negative bacteria was acceptable. The minimum inhibitory concentration of this nano-powder was determined. The results showed that MIC values for E. coli, K. pneumoniae, M. luteus and S. aureus were about 2.3 ?g/mL, 7.3 ?g/mL, 3 ?g/mL and 12 ?g/mL, respectively. Minimum bactericidal concentration (MBC) was also evaluated and showed that the growth of E. coli, K. pneumoniae, M. luteus and S. aureus could be decreased at 2.3, 14, 3 and 18 ?g/mL of BZT. Average log reduction in viable bacteria count in time-kill assay ranged between 6 Log10 cfu/mL to zero after 24 h of incubation with BZT nanoparticle. PMID:25763046

  16. Detection of indentation induced Fe-to-Afe phase transformation in lead zirconate titanate.

    SciTech Connect

    Baddorf, Arthur P.; Shin, Junsoo; Gogotsi, Yury G.; Buchheit, Thomas Edward; Watson, Chad Samuel; Kalinin, Sergei; Juliano, Thomas F.

    2005-08-01

    Instrumented indentation was combined with microscopy and spectroscopy analysis to investigate the local mechanically induced ferroelectric to anti-ferroelectric phase transformation of niobium-modified lead zirconate titanate 95/5. Indentation experiments to a depth of 2 {micro}m were performed using a Berkovich pyramidal three-sided diamond tip. Subsequent Raman spectroscopy and piezoelectric force microscopy revealed that indentation locally induced the ferroelectric to antiferroelectric phase transformation. Piezoelectric force microscopy demonstrated the ability to map the individual phases within and near indented regions on the niobium-modified lead zirconate titanate ceramics.

  17. Piezoelectric thick bismuth titanate/lead zirconate titanate composite film transducers for smart NDE of metals

    NASA Astrophysics Data System (ADS)

    Kobayashi, M.; Jen, C.-K.

    2004-08-01

    Thick film piezoelectric ceramic sensors have been successfully deposited on different metallic substrates with different shapes by a sol-gel spray technique. The ball-milled bismuth titanate fine powders were dispersed into PZT solution to achieve the gel. The films with desired thickness up to 200 µm have been obtained through the multilayer coating approach. These thick films were also effectively coated onto thin sheet metals of thickness down to 25 µm. Self-support films with flat and shell geometries were made. Piezoelectricity was achieved using the corona discharge poling method. The area of the top silver paste electrode was also optimized. The center frequencies of ultrasonic signals generated by these films ranged from 3.6 to 30 MHz and their bandwidth was broad as well. The ultrasonic signals generated and received by these ultrasonic transducers (UTs) operated in the pulse/echo mode had a signal to noise ratio more than 30 dB. The main advantages of such sensors are that they (1) do not need couplant, (2) can serve as piezoelectric and UT, (3) can be coated onto curved surfaces and (4) can operate up to 440 °C. The capability of these thick film UTs for non-destructive evaluation of materials at 440 °C has been demonstrated.

  18. Raman study of lead zirconate titanate under uniaxial stress

    SciTech Connect

    TALLANT, DAVID R.; SIMPSON, REGINA L.; GRAZIER, J. MARK; ZEUCH, DAVID H.; OLSON, WALTER R.; TUTTLE, BRUCE A.

    2000-04-01

    The authors used micro-Raman spectroscopy to monitor the ferroelectric (FE) to antiferroelectric (AFE) phase transition in PZT ceramic bars during the application of uniaxial stress. They designed and constructed a simple loading device, which can apply sufficient uniaxial force to transform reasonably large ceramic bars while being small enough to fit on the mechanical stage of the microscope used for Raman analysis. Raman spectra of individual grains in ceramic PZT bars were obtained as the stress on the bar was increased in increments. At the same time gauges attached to the PZT bar recorded axial and lateral strains induced by the applied stress. The Raman spectra were used to calculate an FE coordinate, which is related to the fraction of FE phase present. The authors present data showing changes in the FE coordinates of individual PZT grains and correlate these changes to stress-strain data, which plot the macroscopic evolution of the FE-to-AFE transformation. Their data indicates that the FE-to-AFE transformation does not occur simultaneously for all PZT grains but that grains react individually to local conditions.

  19. Oriented lead zirconate titanate thin films: Characterization of film crystallization

    SciTech Connect

    Voigt, J.A.; Tuttle, B.A.; Headley, T.J.; Eatough, M.O.; Lamppa, D.L.; Goodnow, D.

    1993-11-01

    Film processing temperature and time was varied to characterize the pyrochlore-to-perovskite crystallization of solution-derived PZT 20/80 thin films. 3000 {Angstrom} thick films were prepared by spin deposition using <100> single crystal MgO as substrate. By controlled rapid thermal processing, films at different stages in the perovskite crystallization process were prepared with the tetragonal PZT 20/80 phase being <100>/<001> oriented relative to the MgO surface. An activation energy for the conversion process of 326 kJ/mole was determined by use of an Arrhenius expression using rate constants found by application of the method of Avrami. Activation energy for formation of the PZT 20/80 perovskite phase of the solution-derived films compared favorably with that calculated from data by Kwok and Desu for sputter-deposited 3500 {Angstrom} thick PZT 55/45 films. Similarity in activation energies indicates that the energetics of the conversion process are not strongly dependent on the method used for film deposition.

  20. Ultra-low voltage ferroelectric electron emission from lead zirconate titanate thin films with nanostructured top electrodes

    NASA Astrophysics Data System (ADS)

    Becherer, J.; Mieth, O.; Vidyarthi, V. S.; Gerlach, G.; Eng, L. M.

    2011-07-01

    Electron emission from thin ferroelectric Pb(Zr0.4 Ti0.6)O3 films is demonstrated reaching emission current densities of up to 3×10-8 A cm-2 for pulsed excitation voltages of 60 V. Nevertheless, the emission process sets in at voltages as low as 10 V. Thin lead zirconate titanate (PZT) films were prepared with a structured top electrode, which exhibits nanometer-sized regularly arranged apertures. The emission current was measured under UHV conditions by both a single electron detector for small emission currents and an amperemeter for larger currents. The voltage dependent polarization state within the emission apertures was imaged using piezoresponse force microscopy and revealed that an increased fraction of the free surface area is switched by an increased applied voltage. This shows that the emission process is strongly correlated to the switching of ferroelectric polarization. Moreover, with the help of a metal grid in front of the detector, the maximum kinetic energy of emitted electrons was investigated and found to be limited by the excitation voltage, only.

  1. Lead zirconate titanate nanowire textile nanogenerator for wearable energy-harvesting and self-powered devices.

    PubMed

    Wu, Weiwei; Bai, Suo; Yuan, Miaomiao; Qin, Yong; Wang, Zhong Lin; Jing, Tao

    2012-07-24

    Wearable nanogenerators are of vital importance to portable energy-harvesting and personal electronics. Here we report a method to synthesize a lead zirconate titanate textile in which nanowires are parallel with each other and a procedure to make it into flexible and wearable nanogenerators. The nanogenerator can generate 6 V output voltage and 45 nA output current, which are large enough to power a liquid crystal display and a UV sensor. PMID:22713250

  2. A PZT nanofiber composites sensor for structure health monitoring

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Shi, Yong

    2011-04-01

    A nanoscale active fiber composites (NAFCs) based acoustic emission (AE) sensor with high sensitivity is developed. The lead zirconate titanate (PZT) nanofibers, with the diameter of approximately 80 nm, were electrospun on a silicon substrate. Nanofibers were parallel aligned on the substrate under a controlled electric field. The interdigitated electrodes were deposited on the PZT nanofibers and packaged by spinning a thin soft polymer layer on the top of the sensor. The hysteresis loop shows a typical ferroelectric property of as-spun PZT nanofibers. The mathematical model of the voltage generation when the elastic waves were reaching to sensor was studied. The sensor was tested by mounting on a steel surface and the measured output voltage under the periodic impact of a grounded steel bar was over 35 mV. The small size of the developed PZT NAFCs AE sensor shows a promising application in monitoring the structures by integrated into composites.

  3. Power harvesting using PZT ceramics embedded in orthopedic implants.

    PubMed

    Chen, Hong; Liu, Ming; Jia, Chen; Wang, Zihua

    2009-09-01

    Battery lifetime has been the stumbling block for many power-critical or maintenance-free real-time embedded applications, such as wireless sensors and orthopedic implants. Thus a piezoelectric material that could convert human motion into electrical energy provides a very attractive solution for clinical implants. In this work, we analyze the power generation characteristics of stiff lead zirconate titanate (PZT) ceramics and the equivalent circuit through extensive experiments. Our experimental framework allows us to explore many important design considerations of such a PZT-based power generator. Overall we can achieve a PZT element volume of 0.5 x 0.5 x 1.8 cm, which is considerably smaller than the results reported so far. Finally, we outline the application of our PZT elements in a total knee replacement (TKR) implant. PMID:19812004

  4. Low Temperature Sintering of PZT

    NASA Astrophysics Data System (ADS)

    Medesi, A.; Greiner, T.; Benkler, M.; Megnin, C.; Hanemann, T.

    2014-11-01

    This paper describes the fabrication and characterization of lead zirconate titanate (PZT) films fired in a liquid-phase sintering process at 900 °C in air. In detail the manufacturing of piezoelectric multilayers with internal pure silver (Tm = 961 °C) electrodes are reported. The feasibility of ten sintering aids in two different volume fractions was investigated for a commercial hard PZT powder (PIC 181, PI Ceramics) with respect to density, microstructure, mechanical behaviour, and piezoelectric properties. Li2O, Li2CO3, PbO, MnO2, V2O5, CuO, Bi2O3, the eutectic mixtures Cu2O·PbO and PbO·WO3 and the ternary system Li2CO3·Bi2O3·CuO (LBCu) have been tested as liquid phase sintering aids. The combination of PZT with LBCu showed the best results. With 5 vol.% LBCu an average relative density of 97% and a characteristic breaking strength of 77 MPa was achieved. Composition of PZT with 2 vol.% LBCu exhibits the highest averaged piezoelectrical charge constant (d33) of 181 pC/N.

  5. Structural description of the macroscopic piezo- and ferroelectric properties of lead zirconate titanate.

    PubMed

    Hinterstein, M; Rouquette, J; Haines, J; Papet, Ph; Knapp, M; Glaum, J; Fuess, H

    2011-08-12

    An in situ structural description of the origin of the ferroelectric properties as a function of the applied electric field E was obtained by synchrotron x-ray diffraction. A setup was used to average the effects of the preferred orientation induced by the strong piezoelectric strain and solve in situ the crystal structure as a function of the applied electric field. Hence, we were able to describe the microscopic origin of the macroscopic ferro- and piezoelectric properties of the most widely used ferroelectric material, lead zirconate titanate. PMID:21902430

  6. Effects of porosity on dielectric and piezoelectric properties of porous lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Yang, An-Kun; Wang, Chang-An; Guo, Rui; Huang, Yong

    2011-04-01

    We report porous lead zirconate titanate ceramics fabricated by tert-butyl alcohol-based gel-casting process which show a very high thickness electromechanical coupling coefficient (0.77), high hydrostatic figure of merit (9594×10-15 m2/N), and low acoustic impedance (3.7 Mrayls). We show that the porosity effectively affects the performance of the samples in two ways: (1) a higher porosity simplifies the resonance behavior, leading to more efficient energy transduction; (2) its replacement of active ceramic phase leads to low relative permittivity, high hydrostatic figure of merit, and low acoustic impedance. It was confirmed the properties could be tailored by controlling the porosity.

  7. PVDF-PZT nanocomposite film based self-charging power cell

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Zhang, Yujing; Xue, Xinyu; Cui, Chunxiao; He, Bin; Nie, Yuxin; Deng, Ping; Wang, Zhong Lin

    2014-03-01

    A novel PVDF-PZT nanocomposite film has been proposed and used as a piezoseparator in self-charging power cells (SCPCs). The structure, composed of poly(vinylidene fluoride) (PVDF) and lead zirconate titanate (PZT), provides a high piezoelectric output, because PZT in this nanocomposite film can improve the piezopotential compared to the pure PVDF film. The SCPC based on this nanocomposite film can be efficiently charged up by the mechanical deformation in the absence of an external power source. The charge capacity of the PVDF-PZT nanocomposite film based SCPC in 240 s is ˜0.010 ?A h, higher than that of a pure PVDF film based SCPC (˜0.004 ?A h). This is the first demonstration of using PVDF-PZT nanocomposite film as a piezoseparator for SCPC, and is an important step for the practical applications of SCPC for harvesting and storing mechanical energy.

  8. PVDF-PZT nanocomposite film based self-charging power cell.

    PubMed

    Zhang, Yan; Zhang, Yujing; Xue, Xinyu; Cui, Chunxiao; He, Bin; Nie, Yuxin; Deng, Ping; Lin Wang, Zhong

    2014-03-14

    A novel PVDF-PZT nanocomposite film has been proposed and used as a piezoseparator in self-charging power cells (SCPCs). The structure, composed of poly(vinylidene fluoride) (PVDF) and lead zirconate titanate (PZT), provides a high piezoelectric output, because PZT in this nanocomposite film can improve the piezopotential compared to the pure PVDF film. The SCPC based on this nanocomposite film can be efficiently charged up by the mechanical deformation in the absence of an external power source. The charge capacity of the PVDF-PZT nanocomposite film based SCPC in 240 s is ?0.010 ?A h, higher than that of a pure PVDF film based SCPC (?0.004 ?A h). This is the first demonstration of using PVDF-PZT nanocomposite film as a piezoseparator for SCPC, and is an important step for the practical applications of SCPC for harvesting and storing mechanical energy. PMID:24531887

  9. Temperature effects on the mechanical behaviour of PZT 95/5

    NASA Astrophysics Data System (ADS)

    Khan, A. S.; Balzer, J. E.; Wilgeroth, J. M.; Proud, W. G.

    2014-05-01

    This research is to develop a better understanding of the piezoelectric ceramic lead zirconate titanate (PZT) 95/5 with varying temperatures, porosities and strain rates. Here, unpoled PZT samples of two different porosities were subjected to a range of compression rates, using quasi-static loading equipment, drop-weight towers and Split Hopkinson Pressure Bars (SHPBs). Varying temperatures were achieved using purpose-made environmental chambers. The resulting stress-strain relationships are compared. The samples were square tiles, 7.5 × 7.5 mm and 3 mm thickness. The density of the standard PZT used here was 7.75 g cm-3 (henceforth described as PZT), whilst the density of the higher porosity PZT was 7.38 g cm-3 (henceforth described as PPZT). This research is part of a wider study.

  10. Topographical Evolution of Lead Zirconate Titanate (PZT) Thin Films Patterned by Micromolding in Capillaries

    E-print Network

    Aksay, Ilhan A.

    silicon-based integrated circuit (IC) manufacturing methods and materials are combined with specialized-based IC manufacturing but are of limited utility to proposed thin film materials such as inorganic implementation of thin film ferroelectric materials in micrometer scale structures requires new additive

  11. Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring

    NASA Astrophysics Data System (ADS)

    Dagdeviren, Canan; Su, Yewang; Joe, Pauline; Yona, Raissa; Liu, Yuhao; Kim, Yun-Soung; Huang, Yongan; Damadoran, Anoop R.; Xia, Jing; Martin, Lane W.; Huang, Yonggang; Rogers, John A.

    2014-08-01

    The ability to measure subtle changes in arterial pressure using devices mounted on the skin can be valuable for monitoring vital signs in emergency care, detecting the early onset of cardiovascular disease and continuously assessing health status. Conventional technologies are well suited for use in traditional clinical settings, but cannot be easily adapted for sustained use during daily activities. Here we introduce a conformal device that avoids these limitations. Ultrathin inorganic piezoelectric and semiconductor materials on elastomer substrates enable amplified, low hysteresis measurements of pressure on the skin, with high levels of sensitivity (~0.005?Pa) and fast response times (~0.1?ms). Experimental and theoretical studies reveal enhanced piezoelectric responses in lead zirconate titanate that follow from integration on soft supports as well as engineering behaviours of the associated devices. Calibrated measurements of pressure variations of blood flow in near-surface arteries demonstrate capabilities for measuring radial artery augmentation index and pulse pressure velocity.

  12. Preparation of Lead Zirconate Titanate (Pb(Zr0.52Ti0.48)O3) by Homogeneous Precipitation and Calcination

    E-print Network

    Tas, A. Cuneyt

    Preparation of Lead Zirconate Titanate (Pb(Zr0.52Ti0.48)O3) by Homogeneous Precipitation-ray spectroscopy (EDXS). I. Introduction LEAD ZIRCONATE TITANATE (PbZrxTi1-xO3) ceramics are of great technological, and TiO2). However, because of intermediate reactions which lead to the formation of PbTiO3 (PT) and Pb

  13. Ultra large deflection of thin PZT/aluminium cantilever beam

    NASA Astrophysics Data System (ADS)

    Seveno, Raynald; Guiffard, Benoit; Regoin, Jean-Pierre

    2015-04-01

    Flexible piezoelectric cantilever beam has been realized by depositing lead zirconate titanate (PZT) thin film (4.5 ?m) by chemical solution deposition (CSD) onto very thin aluminium foil (16 ?m). The tip deflection of the beam has been measured as a function of the frequency of the applied sinusoidal voltage to the PZT film for different amplitudes. Resonance curves have been compared to a classical model of an oscillating system under sinusoidal stress with a very good agreement. Despite of weak ferroelectric properties (remnant polarization: 13 ?C/cm2), ultra-large deflection amplitudes have been measured under very moderate applied voltage values: 750 ?m@10 V for quasi-static mode and 5 mm@10 V at the resonance frequency ( 12 Hz), which makes this PZT/aluminium composite film very promising for highly flexible actuation applications where large displacements are wanted.

  14. Optical and Photoelectrochemical Properties of Lead Zirconate Titanate Thin Films Obtained by the Sol-Gel Method

    NASA Astrophysics Data System (ADS)

    Poznyak, S. K.; Kulak, A. I.

    2014-11-01

    We obtained optically transparent n-type semiconductor films of lead zirconate titanate Pb(ZrxTi1-x)O3 by reaction of individual sols of hydrated titanium dioxide and zirconium dioxide with lead ions, followed by heat treatment at 500-800°C. We established that these films, when in contact with an aqueous electrolyte, can generate a photopotential and a photocurrent when exposed to UV radiation (250-400 nm). The average values of the bandgap energy from optical absorption and photocurrent spectroscopy data are slightly dependent on the composition of the lead zirconate titanate solid solution (they increase by 0.07-0.12 eV on going from Pb(Zr0.2Ti0.8)O3 to Pb(Zr0.52Ti0.48)O3), which may be connected with features of the band structure in these materials.

  15. Pressure wave and fluid velocity in a bend-mode inkjet nozzle with double PZT actuators

    NASA Astrophysics Data System (ADS)

    Kim, Sungu; Sung, Jaeyong; Lee, Myeong Ho

    2013-02-01

    A new concept of bend-mode inkjet nozzle with double PZT (lead zirconate titanate) actuators has been designed and fabricated in the present study. Then the pressure wave and fluid velocity at the nozzle exit have been investigated. The complex pressure behavior inside the channel was solved numerically based on the narrow channel acoustic theory. The two PZTs attached to a rectangular channel were actuated sequentially by setting the waveforms of each PZT to be center-aligned with various pulse widths. As a result, the double PZT actuation is superior to the single PZT actuation in view of strong momentum force and fast dissipation of residual pressure. The maximum fluid velocity at the nozzle exit is observed when the respective pulse widths equal to their optimum pulse widths. The numerical results are supported by the experimental results with the fabricated inkjet device by measuring the speed of meniscus just out of the nozzle.

  16. New Fabrication of High-Frequency (100-MHz) Ultrasound PZT Film Kerfless Linear Array

    PubMed Central

    Zhu, Benpeng; Chan, Ngai Yui; Dai, Jiyan; Shung, K. Kirk; Takeuchi, Shinichi; Zhou, Qifa

    2013-01-01

    The paper describes the design, fabrication, and measurements of a high-frequency ultrasound kerfless linear array prepared from hydrothermal lead zirconate titanate (PZT) thick film. The 15-µm hydrothermal PZT thick film with an area of 1 × 1 cm, obtained through a self-separation process from Ti substrate, was used to fabricate a 32-element 100-MHz kerfless linear array with photolithography. The bandwidth at ?6 dB without matching layer, insertion loss around center frequency, and crosstalk between adjacent elements were measured to be 39%, ?30 dB, and ?15 dB, respectively. PMID:23549547

  17. Effect of crystallinity on thermal transport in textured lead zirconate titanate thin films.

    PubMed

    Varghese, Ronnie; Harikrishna, Hari; Huxtable, Scott T; Reynolds, W T; Priya, Shashank

    2014-05-14

    We demonstrate the use of the time domain thermoreflectance (TDTR) technique towards understanding thermal transport in textured Pb(Zr,Ti)O3 (PZT) thin films grown by a sol-gel process on platinized silicon substrates. PZT films were grown with preferred crystallographic orientations of (100), (110), and (111). Grain orientation was controlled by manipulating the heterogeneous nucleation and growth characteristics at the interface between the film and the underlying Pt layer on the substrate. TDTR was used to measure both the PZT film thermal conductivity and the interface thermal conductance between the PZT and Pt as well as that between the PZT and an Al thermoreflectance layer evaporated on the PZT surface. We find a hierarchical dependence of thermal conductivity on the crystallographic orientation of the PZT films and observed differences in the thermal conductances between the Al-PZT and PZT-Pt interfaces for a varying degree of preferred orientations (100), (110), and (111). Thus, the technique based upon nanoscale thermal measurements can be used to delineate PZT samples with different crystallographic orientations. The thermal conductivities of the PZT films with different crystal orientations were in the range of 1.45-1.80 W m(-1) K(-1). The interface thermal conductance between the PZT and Pt layer was in the range of 30-65 MW m(-2) K(-1), while the conductance between the Al layer and PZT was in the range of 90-120 MW m(-2) K(-1). These interfacial conductances exhibit significant correlations to the texture of the PZT film and elemental concentration and densities at those interfaces. PMID:24689852

  18. Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

    SciTech Connect

    Hernandez-Sanchez, Bernadette A.; Tuttle, Bruce Andrew

    2009-06-01

    Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

  19. Optical anisotropy near the relaxor-ferroelectric phase transition in lanthanum lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Moore, Nathan W.; Brown-Shaklee, Harlan J.; Rodriguez, Mark A.; Brennecka, Geoff L.

    2013-08-01

    We examine the optical activity, birefringence, and transparency of Lanthanum-doped, lead zirconate titanate (PLZT 7/65/35) bulk ceramic wafer sections over visible and near-IR spectra and on heating. Optical transitions are compared to both crystallographic (rhombohedral-cubic) and domain (relaxor-ferroelectric) transitions identified with x-ray diffraction, dielectric, and calorimetry measurements. Optical activity and birefringence are shown to be enhanced for disordered domains near room temperature, to attenuate above the relaxor-ferroelectric transition and to gradually decay above the Curie point regardless of the initial poling state. The results are interpreted in light of the change of crystallographic symmetry due to the local strains induced by ferroelectric architecture. The heterogeneous local strains more strongly influence the optical properties than the macro-scale structure of the polycrystalline PLZT ceramic. This mechanism is significant for understanding optical rotation and birefringence in polycrystalline systems. Finally, the specific rotation (up to 350°/mm) lies among the highest reported for crystalline materials. Along with strong poling contrast and comparatively small dispersion for the unpoled state, these properties are promising for electro-optics applications.

  20. Effect of compositional variations in the lead lanthanum zirconate stannate titanate system on electrical properties

    SciTech Connect

    Markowski, K.; Park, S.E.; Yoshikawa, Shoko; Cross, L.E.

    1996-12-01

    The purpose of this work was to evaluate the effect of compositional modifications on the electrical properties of lead lanthanum zirconate stannate titanate (PLZST) ceramics, as well as to examine their electrically induced phase-change behavior. Variations in the Ti:Sn ratio were evaluated. Increased Ti{sup 4+} content produced the following: decreased switching field, related to an increased antiferroelectric-ferroelectric (AFE-FE) transition temperature; constant hysteresis ({Delta}E) correlated with a constant temperature of the maximum dielectric constant (T{sub max}); a sharper dielectric-constant maximum peak; and increased room-temperature dielectric constant (K). Variations in the Zr:Sn ratio also were evaluated. Increased Zr{sup 4+} content produced the following: increased hysteresis with increased T{sub max}, decreased maximum dielectric constant, and decreased switching field with increased AFE-FE transition temperature (T{sub AFE-FE}). From these results, with respect to compositional modifications, the AFE-FE switching field (E{sub AFE-FE}) and {Delta}E were observed to be dependent strongly on T{sub AFE-FE} and T{sub max}, respectively. Negligible change existed in the strain achievable at the switching field, which remained constant for all compositions at {approximately}0.16%. The significance of this research was the ability demonstrated to tailor the properties of phase-change materials through compositional modifications.

  1. Develop techniques for ion implantation of (lead-lanthanum-zirconate-titanate) for adaptive optics

    NASA Astrophysics Data System (ADS)

    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 C. This report summarizes the research and provides a sampling of the data taken during the report period.

  2. Microstrain in tetragonal lead-zirconate-titanate: The effect of pressure on the ionic displacements

    SciTech Connect

    Frantti, J. Fujioka, Y.; Zhang, J.; Zhu, J.; Vogel, S. C.; Zhao, Y.

    2014-08-15

    Piezoelectric materials respond to external stimuli by adjusting atomic positions. In solid-solutions, the changes occurring in atomic scale are very complex since the short- and long-range order are different. Standard methods used in diffraction data analysis fail to model the short-range order accurately. Pressure-induced cation displacements in ferroelectric Pb(Zr{sub 0.45}Ti{sub 0.55})O{sub 3} perovskite oxide are modeled by starting from a short-range order. We show that the model gives the average structure correctly and properly describes the local structure. The origin of the microstrain in lead zirconate titanate is the spatially varying Zr and Ti concentration and atomic distances, which is taken into account in the simulation. High-pressure neutron powder diffraction and simulation techniques are applied for the determination of atomic positions and bond-valences as a function of pressure. Under hydrostatic pressure, the material loses its piezoelectric properties far before the transition to the cubic phase takes place. The total cation valence +6 is preserved up to 3.31 GPa by compensating the increasing B-cation valence by decreasing Pb-displacement from the high-symmetry position. At 3.31 GPa, Pb-displacement is zero and the material is no more ferroelectric. This is also the pressure at which the Pb-valence is minimized. The average structure is still tetragonal. The model for microstrain predicts that the transition occurs over a finite pressure range: Pb-displacements are spatially varying and follow the distribution of Zr and Ti ions.

  3. Thermally induced modifications of the optic properties of lead zirconate titanate thin films obtained on different substrates by sol-gel synthesis

    NASA Astrophysics Data System (ADS)

    D'Elia, Stefano; Castriota, Marco; Policicchio, Alfonso; Scaramuzza, Nicola; Versace, Carlo; Cazzanelli, Enzo; Agostino, Raffaele Giuseppe; Vena, Carlo; Strangi, Giuseppe; Bartolino, Roberto

    2008-12-01

    Lead zirconium titanate PbZr0.53Ti0.47O3 (PZT) thin films have been obtained by sol-gel synthesis, deposited on different substrates [float glass, indium tin oxide (ITO)-coated float glass, and intrinsic silicon wafer], and later subjected to different thermal treatments. The morphologic and the structural properties of both PZT thin films and substrates have been investigated by scanning electron microscope and their composition was determined by energy dispersive x-ray (EDX) analysis. Moreover, variable angle spectroscopic ellipsometry provides relevant information on the electronic and optical properties of the samples. In particular, the optical constant dispersion of PZT deposited on ITO-coated float glasses shows a small absorption resonance in the near IR region, not observed in PZT films deposited on the other substrates, so that such absorption resonance can be explained by interfacial effects between ITO and PZT layers. This hypothesis is also supported by EDX measurements, showing an interdiffusion of lead and indium ions, across the PZT-ITO interface, that can generate a peculiar charge distribution in this region.

  4. Piezoelectric Energy Harvesting Using PZT Bimorphs and Multilayered Stacks

    NASA Astrophysics Data System (ADS)

    Panda, Prasanta Kumar; Sahoo, Benudhar; Chandraiah, M.; Raghavan, Sreekumari; Manoj, Bindu; Ramakrishna, J.; Kiran, P.

    2015-11-01

    Piezoelectric materials have a unique ability to interchange electrical and mechanical energy. This property allows the absorption of mechanical energy such as ambient vibration and its transformation into electrical energy. The electrical energy generated can be used to power low-power electronic devices. In the present study, energy harvesting by lead zirconate titanate (PZT) multilayer (ML) stacks and bimorphs is presented. The devices were fabricated by a tape casting technique and were poled at 2 kV/mm for 30 min immersed in a silicone oil bath maintained at 60°C. The energy harvesting characteristics of the fabricated devices were measured in a suitably assembled test setup. The output voltage obtained from the PZT bimorphs and ML stacks was 450 mV and 125 mV, respectively. The higher output voltage from the bimorph is due to its low capacitance.

  5. Temperature Dependent Mechanical Property of PZT Film: An Investigation by Nanoindentation

    PubMed Central

    Li, Yingwei; Feng, Shangming; Wu, Wenping; Li, Faxin

    2015-01-01

    Load-depth curves of an unpoled Lead Zirconate Titanate (PZT) film composite as a function of temperature were measured by nanoindentation technique. Its reduce modulus and hardness were calculated by the typical Oliver-Pharr method. Then the true modulus and hardness of the PZT film were assessed by decoupling the influence of substrate using methods proposed by Zhou et al. and Korsunsky et al., respectively. Results show that the indentation depth and modulus increase, but the hardness decreases at elevated temperature. The increasing of indentation depth and the decreasing of hardness are thought to be caused by the decreasing of the critical stress needed to excite dislocation initiation at high temperature. The increasing of true modulus is attributed to the reducing of recoverable indentation depth induced by back-switched domains. The influence of residual stress on the indentation behavior of PZT film composite was also investigated by measuring its load-depth curves with pre-load strains. PMID:25768957

  6. Temperature dependent mechanical property of PZT film: an investigation by nanoindentation.

    PubMed

    Li, Yingwei; Feng, Shangming; Wu, Wenping; Li, Faxin

    2015-01-01

    Load-depth curves of an unpoled Lead Zirconate Titanate (PZT) film composite as a function of temperature were measured by nanoindentation technique. Its reduce modulus and hardness were calculated by the typical Oliver-Pharr method. Then the true modulus and hardness of the PZT film were assessed by decoupling the influence of substrate using methods proposed by Zhou et al. and Korsunsky et al., respectively. Results show that the indentation depth and modulus increase, but the hardness decreases at elevated temperature. The increasing of indentation depth and the decreasing of hardness are thought to be caused by the decreasing of the critical stress needed to excite dislocation initiation at high temperature. The increasing of true modulus is attributed to the reducing of recoverable indentation depth induced by back-switched domains. The influence of residual stress on the indentation behavior of PZT film composite was also investigated by measuring its load-depth curves with pre-load strains. PMID:25768957

  7. Properties of Sr- and Sb-doped PZT-Portland cement composites

    NASA Astrophysics Data System (ADS)

    Chaipanich, A.; Rujijanagul, G.; Tunkasiri, T.

    2009-02-01

    Lead zirconate titanate (PZT) ceramic-cement-based composites have increasingly been recognized as an attractive new composite material for use as a sensor in structural applications. In this work, PZT was doped with Sr and Sb (PSZT) to give it greater dielectric constant ( ? r) and higher piezoelectric coefficient ( d 33) values than normal PZT and is the first time that it is mixed with normal Portland cement to produce a 0-3 connectivity PSZT-Portland cement composite using PSZT contents of 50% and 70% by volume. Scanning electron micrographs show PSZT ceramic particles closely surrounded by the hydrated cement matrix where a dense microstructure can be observed in the interfacial zone. Both the ? r and d 33 values were found to increase with PSZT content and the values are amongst the highest so far for these types of composites, where the ? r and d 33 values reached 590 and 48 pC/N, respectively.

  8. Domain pinning near a single-grain boundary in tetragonal and rhombohedral lead zirconate titanate films

    NASA Astrophysics Data System (ADS)

    Marincel, D. M.; Zhang, H. R.; Britson, J.; Belianinov, A.; Jesse, S.; Kalinin, S. V.; Chen, L. Q.; Rainforth, W. M.; Reaney, I. M.; Randall, C. A.; Trolier-McKinstry, S.

    2015-04-01

    The interaction of grain boundaries with ferroelectric domain walls strongly influences the extrinsic contribution to piezoelectric activity in Pb Zr1 -x,TixO3 (PZT), ubiquitous in modern transducers and actuators. However, the fundamental understanding of these phenomena has been limited by complex mechanisms originating from the interplay of atomic-level domain wall pinning, collective domain wall dynamics, and emergent mesoscopic behavior. This contribution utilizes engineered grain boundaries created by depositing epitaxial PZT films with various Zr:Ti ratios onto 24° tilt SrTi O3 bicrystals. The nonlinear piezoelectric response and surface domain structure across the boundary are investigated using piezoresponse force microscopy while the cross-sectional domain structure is studied using transmission electron microscopy. The grain boundary reduces domain wall motion over a width of 800 ±70 nm for PZT 45:55 and 450 ±30 nm for PZT 52:48. Phase field modeling provides an understanding of the elastic and electric fields associated with the grain boundary and local domain configurations. This study demonstrates that complex mesoscopic behaviors can be explored to complement atomic-level pictures of the material system.

  9. Grain growth kinetics and electrical properties of lanthanum modified lead zirconate titanate (9/65/35) based ferroelectric ceramics

    SciTech Connect

    Roca, R. Alvarez; Guerrero, F.; Botero, E. R.; Garcia, D.; Eiras, J. A.; Guerra, J. D. S.

    2009-01-01

    The influence of the microstructural characteristics on the dielectric and electrical properties has been investigated for Nd{sup 3+} doped lanthanum modified lead zirconate titanate ferroelectric ceramics, obtained by the conventional solid-state reaction method, by taking into account different sintering conditions. The grain growth mechanism has been investigated and a cubic-type grain growth law was observed for samples with grain size varying from 1.00 up to 2.35 {mu}m. The porosity and grain size dependences of the phase transition parameters, such as the maximum dielectric permittivity and its corresponding temperature ({epsilon}{sub m} and T{sub m}, respectively) were also investigated. The ac conductivity analyses followed the universal Jonscher law. The behavior of the frequency exponent (s) was analyzed through the correlated barrier hopping model. Both ac and dc conductivity results have been correlated with the observed microstructural features.

  10. Deformation in lead zirconate titanate ceramics under large signal electric field loading measured by digital image correlation

    NASA Astrophysics Data System (ADS)

    Chen, Di; Kamlah, Marc

    2015-11-01

    Digital image correlation, a noncontact and nondestructive method, was employed to monitor the deformation of lead zirconate titanate piezoelectric ceramics. This method is based on imaging a speckle pattern on the specimen surface during the test and subsequently correlating each image of the deformed pattern to that in the reference state. In our work, both longitudinal and transverse strains were calculated from imaging a bulk sample under a ±2 kV/mm electric field. Compared with linear variable displacement transducer data, the results from this correlation method were validated. At the same time, based on this optical technique, different strain-electric field butterfly loops can be drawn from correspondingly selected regions of interest. Combined with contour plots of strain on the surface of the sample, the deformation of bulk ceramic sample under uniaxial electric field loading without any mechanical constraints is proven to be highly homogenous under macro-observing scale.

  11. Modified Johnson model for ferroelectric lead lanthanum zirconate titanate at very high fields and below Curie temperature.

    SciTech Connect

    Narayanan, M.; Tong, S.; Ma, B.; Liu, S.; Balachandran, U.

    2012-01-01

    A modified Johnson model is proposed to describe the nonlinear field dependence of the dielectric constant ({var_epsilon}-E loop) in ferroelectric materials below the Curie temperature. This model describes the characteristic ferroelectric 'butterfly' shape observed in typical {var_epsilon}-E loops. The predicted nonlinear behavior agreed well with the measured values in both the low- and high-field regions for lead lanthanum zirconate titanate films. The proposed model was also validated at different temperatures below the ferroelectric-to-paraelectric Curie point. The anharmonic coefficient in the model decreased from 6.142 x 10{sup -19} cm{sup 2}/V{sup 2} to 2.039 x 10{sup -19} cm{sup 2}/V{sup 2} when the temperature increased from 25 C to 250 C.

  12. Polar-axis-oriented crystal growth of tetragonal PZT films on stainless steel substrate using pseudo-perovskite nanosheet buffer layer

    NASA Astrophysics Data System (ADS)

    Minemura, Yoshiki; Ichinose, Daichi; Nagasaka, Kohei; Kim, Jin Woon; Shima, Hiromi; Nishida, Ken; Kiguchi, Takanori; Konno, Toyohiko J.; Oshima, Naoya; Funakubo, Hiroshi; Uchida, Hiroshi

    2015-07-01

    Lead zirconate titanate (PZT) film with polar axis orientation was grown on a SUS 316L stainless steel substrate with the help of a Ca2Nb3O10 nanosheet (ns-CN) layer that had a pseudo-perovskite-type crystal structure. The ns-CN buffer layer was supported on a platinized SUS 316L (Pt/SUS) substrate, followed by chemical solution deposition (CSD) of the PZT films with tetragonal symmetry (Zr/Ti =40/60). The PZT films consisting of c-domain, with [001]-axis orientation of the perovskite unit cell, were deposited on the ns-CN/Pt/SUS substrate owing to (i) epitaxial lattice matching between the unit cell of PZT and substrate surface and (ii) in-plane thermal stress applied to the PZT film during cooling-down step of CSD procedure. The c-domain-oriented PZT film on ns-CN/Pt/SUS substrate exhibited enhanced remanent polarization of approximately 52 ?C/cm2 and lowered dielectric permittivity of approximately 230, which are superior to those of conventional PZT films with random crystal orientation and comparable to those of epitaxial PZT films grown on (100)SrRuO3//(100)SrTiO3 substrates.

  13. Titan

    NASA Technical Reports Server (NTRS)

    Owen, Tobias; Gautier, Daniel; Raulin, Francois; Scattergood, Thomas

    1992-01-01

    The following topics are discussed with respect to Titan: observations of the atmosphere; laboratory simulations and theoretical models of Titan's atmosphere; endpoints of atmospheric chemistry - aerosols and oceans; exobiology; and the next steps in understanding Titan.

  14. PZT Thin Film Piezoelectric Traveling Wave Motor

    NASA Technical Reports Server (NTRS)

    Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

    1995-01-01

    With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

  15. Influence of crystal phase and transparent substrates on electro-optic properties of lead zirconate titanate films

    SciTech Connect

    Zhu, M. M.; Du, Z. H.; Ma, J.

    2010-12-01

    Pb(Zr{sub x}Ti{sub 1-x})O{sub 3}[x=0.52, PZT(52) near morphotropic phase boundary], tetragonal PZT(65), and rhombohedral PZT(20) thin films have been fabricated on different transparent substrates by radio frequency sputtering. The optical studies show that the band gap energies and refractive indices of the PZT thin films are crystal phase dependent. The largest electro-optic (EO) coefficient of 219.6 pm/V has been achieved by controlling the crystal phase of the PZT thin films. The linear EO coefficients of PZT(52) films on the (Pb{sub 0.86}La{sub 0.14})TiO{sub 3}-coated glass, indium tin oxides, and MgO substrates are also studied. Such study could contribute to the crystal phase and substrate dependent PZT films for electro-optic devices and multifunctional integrated circuits.

  16. Application of Multiplexed FBG and PZT Impedance Sensors for Health Monitoring of Rocks

    PubMed Central

    Yang, Yaowen; Annamdas, Venu Gopal Madhav; Wang, Chao; Zhou, Yingxin

    2008-01-01

    Reliable structural health monitoring (SHM) including nondestructive evaluation (NDE) is essential for safe operation of infrastructure systems. Effective monitoring of the rock components of civil infrastructures such as tunnels and caverns remains challenging. The feasibility of employing smart optical fibre sensor (OFS) and piezoelectric impedance sensor made up of lead zirconate titanate (PZT) for comprehensive health monitoring of rocks, covering load history monitoring/retrieval as well as damage assessment is presented in this paper. The rock specimens are subjected to cyclic loading and their conditions are continuously monitored using OFS and PZT sensors. OFS based multiplexed fibre Bragg grating (FBG) sensors are surface bonded on the rock specimens. Their strain sensing performance is compared with the conventional electric strain gauges (ESGs). In addition, PZT patches are also bonded on the specimens to study the damage pattern during different loading cycles. Unlike the FBGs or ESGs, PZT patches are used as bi-functional sensors and actuators, enabling them to be efficient detectors of incipient damages using the principle of electromechanical impedance. The experimental study demonstrated superior performance of these smart FBG and PZT impedance sensors. This work is expected to be useful for SHM based NDE application of rock structures such as caverns and tunnels.

  17. A reusable PZT transducer for monitoring initial hydration and structural health of concrete.

    PubMed

    Yang, Yaowen; Divsholi, Bahador Sabet; Soh, Chee Kiong

    2010-01-01

    During the construction of a concrete structure, strength monitoring is important to ensure the safety of both personnel and the structure. Furthermore, to increase the efficiency of in situ casting or precast of concrete, determining the optimal time of demolding is important for concrete suppliers. Surface bonded lead zirconate titanate (PZT) transducers have been used for damage detection and parameter identification for various engineering structures over the last two decades. In this work, a reusable PZT transducer setup for monitoring initial hydration of concrete and structural health is developed, where a piece of PZT is bonded to an enclosure with two bolts tightened inside the holes drilled in the enclosure. An impedance analyzer is used to acquire the admittance signatures of the PZT. Root mean square deviation (RMSD) is employed to associate the change in concrete strength with changes in the PZT admittance signatures. The results show that the reusable setup is able to effectively monitor the initial hydration of concrete and the structural health. It can also be detached from the concrete for future re-use. PMID:22399929

  18. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-07-01

    High energy synchrotron XRD was employed to determine the lattice strain ?{111} and diffraction peak intensity ratio R{200} in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the ?{111}-cos2 ? plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90° ferroelectric domains, quantified in terms of R{200}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks.

  19. Residual stress relief due to fatigue in tetragonal lead zirconate titanate ceramics

    SciTech Connect

    Hall, D. A.; Mori, T.; Comyn, T. P.; Ringgaard, E.; Wright, J. P.

    2013-07-14

    High energy synchrotron XRD was employed to determine the lattice strain {epsilon}{l_brace}111{r_brace}and diffraction peak intensity ratio R{l_brace}200{r_brace}in tetragonal PZT ceramics, both in the virgin poled state and after a bipolar fatigue experiment. It was shown that the occurrence of microstructural damage during fatigue was accompanied by a reduction in the gradient of the {epsilon}{l_brace}111{r_brace}-cos{sup 2} {psi} plot, indicating a reduction in the level of residual stress due to poling. In contrast, the fraction of oriented 90 Degree-Sign ferroelectric domains, quantified in terms of R{l_brace}200{r_brace}, was not affected significantly by fatigue. The change in residual stress due to fatigue is interpreted in terms of a change in the average elastic stiffness of the polycrystalline matrix due to the presence of inter-granular microcracks.

  20. A method to decrease the harmonic distortion in Mn-Zn ferrite/PZT and Ni-Zn ferrite/PZT layered composite rings exhibiting high magnetoelectric effects

    NASA Astrophysics Data System (ADS)

    Loyau, V.; Morin, V.; Fortineau, J.; LoBue, M.; Mazaleyrat, F.

    2015-10-01

    We have investigated the magnetoelectric (ME) effect in layered composite rings subjected to circumferential AC magnetic fields and DC magnetic fields in radial, axial, or circumferential directions. Bilayer samples were obtained combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low magnetostriction saturation ( ?s<10-6 ) and low magneto-crystalline anisotropy constants show high ME capabilities when associated with PZT in ring structures. In certain conditions, these ME effects are higher than those obtained with Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive and mechanical characterizations have given results that explain these high ME performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages responses with low linearity especially at high signal level. Based on the particular structure of the ME device, a method to decrease the nonlinear harmonic distortion of the ME voltages is proposed. Harmonic distortion analysis of ME voltages measured in different configurations allows us to explain the phenomenon.

  1. Ferroelectric domain switching of individual nanoscale grains in polycrystalline lead zirconate titanate thin films

    NASA Astrophysics Data System (ADS)

    Jing, Yuanyuan

    2011-12-01

    This thesis will focus on the switching behavior of nanoscale ferroelectric domains in polycrystalline thin films. Ferroelectrics are a class of dielectric materials that demonstrate spontaneous polarizations under zero applied electric field. A region with the same polarization is called a ferroelectric domain. One important attribute of ferroelectrics is the domain switching from one thermodynamically stable state to another by application of an external electric field. Ferroelectric domain switching has been intensively investigated in epitaxial thin films. However, little is known about the domain switching in polycrystalline thin films. The main reason is that each grain is differently orientated and each is in a unique local stress and electric field determined by neighboring grains. To understand and deterministically control the nanoscale domain switching in polycrystalline thin films, it's critical to experimentally identify the effect of local microstructure (grain orientation and grain boundary misorientation) on the individual grain switching behavior. In this thesis, the effect of local microstructure on domain switching has been quantitatively analyzed in a 100 nm thick polycrystalline PbZr 0.2Ti0.8O3 thin film. The ferroelectric domains are characterized by Piezoresponse Force Microscopy (PFM), with their switching behavior analyzed by Polarization Difference Maps (PDMs, an analytical technique developed in this work). The local microstructure is determined by Electron Back Scattering Diffraction (EBSD). The results are discussed in chapter 3 to 6. Chapter 3 introduces the PDMs technique that enables the rapid identification of 0o, 90o switching and 180o switching in polycrystalline thin films. By assigning different colors to different types of switching, the full nature of polarization switching can be visualized simultaneously for large number of domains or grains in one map. In chapter 4, an external electric field reversal experiment has been carried out in a polycrystalline PZT thin film. Using PDMs, 90° switching of individual grains is identified in addition to the expected 180° switching. What is noteworthy is that a significant number of grains undergo 90° switching in both switching and relaxation processes, a striking contrast with epitaxial thin films where only 180o switching have been reported. In chapter 5, the reason that a large amount of 90o switching occurred in a polycrystalline thin film is studied by experimentally characterizing the local microstructure. The preliminary results show a direct correlation between the crystal orientation of a chosen grain and its switching type, indicating that the switching of a grain is dominated by its orientation. For a minority of the grains, however, the neighboring grain should play a dominant role. The effects of neighboring grains on the center grain switching are studied in chapter 6. Switching loops are carried out at different positions within individual grains. A correlation across grain boundaries in the coercive bias was observed for almost all measured grain boundaries. Even inside the same grain, different grain boundaries can either facilitate or hinder the switching, depending on the grain boundary misorientation. Future work is discussed in chapter 7, including the non-deterministic domain switching in polycrystalline thin films, the influence of electron beams on the domain switching behavior, and the domain relaxation through 90o switching. In conclusion, a large fraction of 90o switching is found in a polycrystalline PZT thin film. The switching of an individual grain is found to be mainly determined by the grain orientation and the grain boundary misorientations. Grains orientated close to the [001] direction are more likely to go through a 90o switching than a 180o switching. Grain boundaries with different misorientation angles tend to either hinder or facilitate the switching of grains on both sides.

  2. Effects of acetylacetone additions on PZT thin film processing

    SciTech Connect

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

    1995-02-01

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

  3. Analyzing the defect structure of CuO-doped PZT and KNN piezoelectrics from electron paramagnetic resonance.

    PubMed

    Jakes, Peter; Kungl, Hans; Schierholz, Roland; Eichel, Rüdiger-A

    2014-09-01

    The defect structure for copper-doped sodium potassium niobate (KNN) ferroelectrics has been analyzed with respect to its defect structure. In particular, the interplay between the mutually compensating dimeric (Cu(Nb)'''-V(O)··) and trimeric (V(O)··-Cu(Nb)'''-V(O)··)· defect complexes with 180° and non-180° domain walls has been analyzed and compared to the effects from (Cu'' - V(O)··)(x)× dipoles in CuO-doped lead zirconate titanate (PZT). Attempts are made to relate the rearrangement of defect complexes to macroscopic electromechanical properties. PMID:25167144

  4. Dielectric properties and field-induced phase switching of lead zirconate titanate stannate antiferroelectric thick films on silicon substrates

    NASA Astrophysics Data System (ADS)

    Xu, Baomin; Ye, Yaohong; Cross, L. Eric

    2000-03-01

    Thick (˜5 ?m) films of antiferroelectric compositions in the lead zirconate titanate stannate family of solid state solutions have been fabricated by sol-gel methods on platinum-buffered silicon substrates. Dielectric properties, electric field induced ferroelectric polarization, and associated elastic strain and the temperature dependence of the dielectric response have been explored as a function of composition. Films with high tin content are shown to undergo a diffuse antiferroelectric-paraelectric phase transition with temperature, probably because of compositional inhomogeneity associated with the high tin content. This type of film also demonstrates a diffuse field-induced antiferroelectric-ferroelectric phase switching under high electric field with the appearance of "slim loop" double hysteresis, which can be attributed to the compositional heterogeneity and the high level of tensile stress in the film because of the thermal mismatch between the film and substrate. On the other hand, the film with high zirconium and low tin content demonstrates a typical antiferroelectric-paraelectric phase change with a sharp peak in dielectric constant on increasing temperature and a typical antiferroelectric-ferroelectric phase switching under high electric field with the appearance of "square loop" double hysteresis. Corresponding to the characteristic of polarization-field hysteresis the film with high tin content possesses a gradual increase of phase switching elastic strain with applied field, reaching a maximum strain level ˜0.38% and suitable for analogue actuation. The film with high zirconium content possesses a sharp jump of phase switching strain with applied field and reaches a maximum strain level ˜0.48%, attractive for high strain digital applications.

  5. In situ transmission electron microscopy study of the electric field-induced transformation of incommensurate modulations in a Sn-modified lead zirconate titanate ceramic

    NASA Astrophysics Data System (ADS)

    He, H.; Tan, X.

    2004-10-01

    Electric field-induced transformation of incommensurate modulations in a Sn-modified lead zirconate titanate ceramic was investigated with an electric field in situ transmission electron microscopy technique. It is found that the spacing between the (1/x){110} satellite spots and the fundamental reflections do not change with external electric field, indicating that the modulation wavelength stays constant under applied field. The intensity of these satellites starts to decrease when the field level reaches a critical value. Further increase in the field strength eventually leads to the complete disappearance of the satellite reflections. In addition, the 1/2 {111}-type superlattice reflections showed no response to electrical stimuli.

  6. Static/dynamic trade-off performance of PZT thick film micro-actuators

    NASA Astrophysics Data System (ADS)

    Bienaimé, Alex; Chalvet, Vincent; Clévy, Cédric; Gauthier-Manuel, Ludovic; Baron, Thomas; Rakotondrabe, Micky

    2015-07-01

    Piezoelectric actuators are widespread in the design of micro/nanorobotic tools and microsystems. Studies toward the integration of such actuators in complex micromechatronic systems require the size reduction of these actuators while retaining a wide range of performance. Two main fabrication processes are currently used for the fabrication of piezoelectric actuators, providing very different behaviors: (i) the use of a bulk lead zirconate titanate (PZT) layer and (ii) the use of thin film growth. In this paper, we propose a trade-off between these two extreme processes and technologies in order to explore the performance of new actuators. This resulted in the design and fabrication of thick film PZT unimorph cantilevers. They allowed a high level of performance, both in the static (displacement) and dynamic (first resonance frequency) regimes, in addition to being small in size. Such cantilever sizes are obtained through the wafer scale bonding and thinning of a PZT plate onto a silicon on insulator wafer. The piezoelectric cantilevers have a 26 ?m thick PZT layer with a 5 ?m thick silicon layer, over a length of 4 mm and a width of 150 ?m. Experimental characterization has shown that the static displacements obtained are in excess of 4.8 ?m V-1 and the resonance frequencies are up to 1103 Hz, which are useful for large displacements and low voltage actuators.

  7. Fast and wide-band response infrared detector using porous PZT pyroelectric thick film

    NASA Astrophysics Data System (ADS)

    Wu, C. G.; Sun, X. Y.; Meng, J.; Luo, W. B.; Li, P.; Peng, Q. X.; Luo, Y. S.; Shuai, Y.

    2014-03-01

    Porous lead zirconate titanate (PbZr0.3Ti0.7O3, PZT30/70) thick films and detectors for pyroelectric applications have been fabricated on alumina substrates by screen-printing technology. Low temperature sintering of PZT thick films have been achieved at 850 °C by using Li2CO3 and Bi2O3 sintering aids. The microstructure of PZT thick film has been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were measured using HP 4284 at 1 kHz under 25 °C. The permittivity and loss tangent of the thick films were 94 and 0.017, respectively. Curie temperature of PZT thick film was 425 °C as revealed by dielectric constant temperature measurement. The pyroelectric coefficient was determined to be 0.9 × 10-8 Ccm-2 K-1 by dynamic current measurement. Infrared detector sensitive element of dual capacitance was fabricated by laser directly write technology. Detectivity of the detectors were measured using mechanically chopped blackbody radiation. Detectivity ranging from 1.23 × 108 to 1.75 × 108 (cm Hz1/2 W-1) was derived at frequency range from 175.5 Hz to 1367 Hz, and D*'s -3 dB cut-off frequency bandwidth was 1.2 kHz. The results indicate that the infrared detectors based on porous thick films have great potential applications in fast and wide-band frequency response conditions.

  8. Titan

    NASA Astrophysics Data System (ADS)

    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. PZT Thin-Film Micro Probe Device with Dual Top Electrodes

    NASA Astrophysics Data System (ADS)

    Luo, Chuan

    Lead zirconate titanate (PZT) thin-film actuators have been studied intensively for years because of their potential applications in many fields. In this dissertation, a PZT thin-film micro probe device is designed, fabricated, studied, and proven to be acceptable as an intracochlear acoustic actuator. The micro probe device takes the form of a cantilever with a PZT thin-film diaphragm at the tip of the probe. The tip portion of the probe will be implanted in cochlea later in animal tests to prove its feasibility in hearing rehabilitation. The contribution of the dissertation is three-fold. First, a dual top electrodes design, consisting of a center electrode and an outer electrode, is developed to improve actuation displacement of the PZT thin-film diaphragm. The improvement by the dual top electrodes design is studied via a finite element model. When the dimensions of the dual electrodes are optimized, the displacement of the PZT thin-film diaphragm increases about 30%. A PZT thin-film diaphragm with dual top electrodes is fabricated to prove the concept, and experimental results confirm the predictions from the finite element analyses. Moreover, the dual electrode design can accommodate presence of significant residual stresses in the PZT thin-film diaphragm by changing the phase difference between the two electrodes. Second, a PZT thin-film micro probe device is fabricated and tested. The fabrication process consists of PZT thin-film deposition and deep reactive ion etching (DRIE). The uniqueness of the fabrication process is an automatic dicing mechanism that allows a large number of probes to be released easily from the wafer. Moreover, the fabrication is very efficient, because the DRIE process will form the PZT thin-film diaphragm and the special dicing mechanism simultaneously. After the probes are fabricated, they are tested with various possible implantation depths (i.e., boundary conditions). Experimental results show that future implantation depths should be less than 3 mm in order to guarantee the first resonant frequency above 60 kHz. Finally, a package for the PZT thin-film micro probe device is developed to ensure its proper function in an aqueous environment, such as inside of cochlea. The package is an insulation layer of parylene coating on the probe. A finite element analysis indicates that a coating thickness of less than 1 mum will reduce the PZT diaphragm displacement by less than 10%. A special fixture is designed to hold a large number of probes for parylene deposition of a thickness of 250 nm. A packaged probe is then submerged in deionized water and functions properly for at least 55 hours. Displacement and impedance of the probe are measured via a laser Doppler vibrometer and an impedance analyzer, respectively. Experimental results show that displacement of the PZT diaphragm increases about 30% in two hours, after the probe is submerged in the deionized water. The impedance measurement shows consistent trends. A hypothesis to explain this unusual phenomenon is diffusion of water molecules into the PZT thin film. High-resolution SEM images of the probe indicate presence of numerous nano-pores in the surface of the PZT thin film, indirectly confirming the hypothesis. Keywords: PZT, Thin-Film, Dual Electrodes, Parylene Coating, Aqueous Environment, Cochlear Implant

  10. An experimental investigation of lead zirconate titanate--epoxy-multi-walled carbon nanotube bulk and flexible thick film composites

    NASA Astrophysics Data System (ADS)

    Banerjee, Sankha

    Piezoelectric sensors and actuators are needed for a wide range of applications from physiological measurement to industrial monitoring systems. Sensors that can be easily integrated with the host, while maintaining high sensitivity and reliability over a wide range of frequencies are not readily feasible and economical with homogenous piezoelectric materials. It is well known that two-phase piezoelectric-epoxy composites offer several benefits over their single phase counterparts, as the properties of the constituent phases combine to improve the range of applicability. However, the piezoelectric properties of these materials suffer from the electrically insulating properties of the epoxy matrix. The electrical properties of the matrix may be enhanced by including electrically conducting inclusions however, less is known about the mechanisms that drive the changes in these properties. Hence, this experimental investigation of sensor materials builds on the previous work in two-phase piezoelectric composites, where the aims are to understand the roles that specific fabrication parameters and inclusion composition play in determining the piezoelectric and dielectric performance the aforementioned composites. The materials under investigation will be comprised of Lead Zirconate Titanate, Epofix Cold-Setting Embedding Resin and multi-walled carbon nanotubes, i.e. the piezoelectric, epoxy and electrical inclusions respectively. Our work suggests that inclusion of MWCNTs enhances the piezoelectric and dielectric properties with increasing volume fraction below the percolation threshold. This work seeks to understand how the processing parameters: poling temperature, poling type and particle distribution influence the contact resistance, space charge double layer at the piezoelectric and conductor interfaces and electric field intensity at the piezoelectric boundary, which all ultimately dictate the piezoelectric and dielectric performance of the composite materials. Conventional solid oxide mixing, spin coating and deposition techniques will be used to fabricate the bulk and thick films. The piezoelectric and dielectric performance will be determined from the measurement of the piezoelectric strain coefficients, d33 and d31, dielectric constant, impedance and dielectric spectrum, dielectric loss tangent, and capacitance. These measurements will be correlated with inclusion size, shape, distribution, and surface morphology observations obtained from the scanning electron microscope (SEM) and transmission electron microscope (TEM).

  11. Rapid Crystallization of Sol-Gel-Deposited Lead Zirconate Titanate Thin Films by 2.45 GHz Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Zhan Jie; Otsuka, Yuka; Cao, Ziping; Yoshikawa, Noboru; Kokawa, Hiroyuki

    2008-09-01

    Pb(Zr0.52Ti0.48)O3 (PZT) thin films were coated onto Pt/Ti/SiO2/Si substrates by a sol-gel method and then crystallized by 2.45 GHz microwave irradiation in a magnetic field. The crystalline phases and microstructures as well as the electrical properties of the microwave-irradiated PZT films were investigated as a function of the elevated temperature generated by microwave irradiation. The perovskite PZT thin films with good electrical properties could be obtained by microwave irradiation at 650 °C for 60 s. The average values of the remanent polarization and the coercive field of the PZT films were approximately 27 ?C/cm2 and 95 kV/cm, respectively, whereas the dielectric constant and loss value measured at 1 kHz were approximately 1100 and 0.18, respectively. It is clear that microwave irradiation is effective for obtaining well-crystallized PZT films with good properties in a short process time.

  12. Aerosol deposited PZT actuated 2D scanner system

    NASA Astrophysics Data System (ADS)

    Schipf, David R.; Chen, Chao-Ting; Kuo, Chun-Liang; Chu, Kang-Yu; Wu, Wen-Jong; Wang, Wei-Chih

    2015-04-01

    A new lead-zirconium-titanate (PZT) actuator design for a micro scanning illuminating device is being developed. The thin PZT film is deposited directly on stainless steel by using an aerosol deposition machine. The aerosol deposition method enables inexpensive, quick, room temperature fabrication while producing high quality PZT films. The presented scanners would be attractive for endoscopic device applications, where inexpensive systems with high resolution would be a move toward disposal endoscopes. The design of this scanning illuminator and fabrication method are presented. Measurements of the PZT layer surface roughness and the aerosol deposited PZT powder particle diameter are presented. Ongoing work and fabrication challenges are discussed.

  13. Titan!

    NASA Astrophysics Data System (ADS)

    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.

  14. Field-enhanced piezoelectric deformation during the high temperature/low temperature rhombohedral (FERh/FERL) phase transformation for tin modified lead zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Yang, Pin; Moore, Roger H.; Burns, George R.

    2002-06-01

    An unusual field-enhanced piezoelectric deformation near the FERH/FERL structural phase transformation was observed in a tin modified lead zirconate titanate solid solution. In addition to the typical field-induced domain reorientation and the piezoelectric strain, this additional field-enhanced deformation only observed near the phase transformation increases linearly with external electric field strength. A 78% increase in field-enhanced strain was observed at a field strength of 32 kV/cm. Comparison of the dielectric susceptibility at low and high field conditions suggests that the observed unusual behavior is created by a field-induced lattice softening during the structural phase transformation. Experimental observations on the field-induced softening phenomena are reported.

  15. An in situ diffraction study of domain wall motion contributions to the frequency dispersion of the piezoelectric coefficient in lead zirconate titanate

    SciTech Connect

    Seshadri, Shruti B.; Prewitt, Anderson D.; Jones, Jacob L.; Studer, Andrew J.; Damjanovic, Dragan

    2013-01-28

    The contribution of non-180 Degree-Sign domain wall displacement to the frequency dependence of the longitudinal piezoelectric coefficient has been determined experimentally in lead zirconate titanate using time-resolved, in situ neutron diffraction. Under subcoercive electric fields of low frequencies, approximately 3% to 4% of the volume fraction of non-180 Degree-Sign domains parallel to the field experienced polarization reorientation. This subtle non-180 Degree-Sign domain wall motion directly contributes to 64% to 75% of the magnitude of the piezoelectric coefficient. Moreover, part of the 33 pm/V decrease in piezoelectric coefficient across 2 orders of magnitude in frequency is quantitatively attributed to non-180 Degree-Sign domain wall motion effects.

  16. A study of PZT thin films and ferroelectric field effect transistors

    NASA Astrophysics Data System (ADS)

    Abdul Basit, Nasir

    Lead zirconate titanate (Pb(Zr,Ti)Osb3 or PZT) is a well known ferroelectric material for its high polarization values, dielectric constant, and resistivity. We have studied PZT films, and ferroelectric field effect transistors (FEFETs) incorporating PZT films. One of the primary factors in synthesis and crystallization of PZT films is the proper control of the lead content of the films. We obtained highly oriented and ferroelectric PZT thin films by RF magnetron sputtering. The stoichiometric PZT target with Zr/Ti ratio of 53/47 was used. No excess lead was used either during sputtering or during post-deposition annealing. Films deposited at 200sp°C or below crystallize into a perovskite phase on receiving anneal treatment at 590sp°C or above. The annealing study, carried out using a conventional furnace, also revealed that the perovskite formation completes during the first 5 minutes of annealing. The annealed films are highly (100) oriented on (111)-Pt coated oxidized Si substrates. Maximum polarization of 36 muC/cmsp2, remanent polarization of 20 muC/cmsp2, and coercive field of 22 kV/cm were obtained with excellent fatigue resistance. This suggests that the low thermal-budget process, low-temperature deposition and short-time anneal in a conventional furnace, with a stoichiometric target may be appropriate as a reliable, simple, and economical method of preparing PZT films. Depositions at 500sp°C or higher, however, resulted in TisbxOsby or ZrTiOsb4 films suggesting that lead was significantly lost during deposition. FEFETs provide a nonvolatile memory with a nondestructive read-out. FEFETs have been fabricated by incorporating a ferroelectric layer in the gate structure of a MOSFET but the interface problems have resulted in devices with poor characteristics. We used an MgO buffer layer between PZT film and Si substrate. A thin oxide layer was grown on Si before MgO deposition to provide a clean channel between source and drain. The devices fabricated in this way clearly show the memory effect. The theoretical aspects were studied and a model was developed for the device based on ferroelectric hysteresis curve. A good comparison between the experimental and model values was observed.

  17. Lanthanide-Assisted Deposition of Strongly Electro-optic PZT Thin Films on Silicon: Toward Integrated Active Nanophotonic Devices.

    PubMed

    George, J P; Smet, P F; Botterman, J; Bliznuk, V; Woestenborghs, W; Van Thourhout, D; Neyts, K; Beeckman, J

    2015-06-24

    The electro-optical properties of lead zirconate titanate (PZT) thin films depend strongly on the quality and crystallographic orientation of the thin films. We demonstrate a novel method to grow highly textured PZT thin films on silicon using the chemical solution deposition (CSD) process. We report the use of ultrathin (5-15 nm) lanthanide (La, Pr, Nd, Sm) based intermediate layers for obtaining preferentially (100) oriented PZT thin films. X-ray diffraction measurements indicate preferentially oriented intermediate Ln2O2CO3 layers providing an excellent lattice match with the PZT thin films grown on top. The XRD and scanning electron microscopy measurements reveal that the annealed layers are dense, uniform, crack-free and highly oriented (>99.8%) without apparent defects or secondary phases. The EDX and HRTEM characterization confirm that the template layers act as an efficient diffusion barrier and form a sharp interface between the substrate and the PZT. The electrical measurements indicate a dielectric constant of ?650, low dielectric loss of ?0.02, coercive field of 70 kV/cm, remnant polarization of 25 ?C/cm(2), and large breakdown electric field of 1000 kV/cm. Finally, the effective electro-optic coefficients of the films are estimated with a spectroscopic ellipsometer measurement, considering the electric field induced variations in the phase reflectance ratio. The electro-optic measurements reveal excellent linear effective pockels coefficients of 110 to 240 pm/V, which makes the CSD deposited PZT thin film an ideal candidate for Si-based active integrated nanophotonic devices. PMID:26043103

  18. Temperature dependence of a PZT piezoelectric sensor for Mercury Dust Monitor up to 150 °C

    NASA Astrophysics Data System (ADS)

    Iwai, Takeo

    We have been developing a cosmic dust detector for BepiColombo Mercury exploration mission, called Mercury Dust Monitor (MDM). The MDM uses piezoelectric sensors made of lead zirconate titanate (PZT) ceramics for estimation of dust flux and momentum of incident particles. The PZT sensors of MDM, installed on the surface of a side panel of the MMO without a sunshade, will be exposed to severe heat influx from the sun. The sensors are expected to reach their maximum temperature of 167 ° C at perihelion. Since the MDM is not just a dust counter but a particle analyzer, the dependence of the impact signals on temperature is essential to deduce quantitative information on the incident particles from the signals. We have carried out experiments on the temperature dependence of impact signals between room temperature and 150 ° C. A halogen lamp heater is used for heating of a disk PZT sensor in a vacuum chamber at the end of a beam line from the electrostatic accelerator at Max Planck Institute for Nuclear Physics (MPI-K). A linear correlation between the output amplitude voltage of the first oscillation and the momentum of accelerated particles remains even at 150 ° C, and, more importantly, there is no clear difference in the slopes of the linear correlation for room temperature and 150 ° C. This result is quite preferable because it should make the practical data analysis from the MDM easy.

  19. Low frequency acoustic energy harvesting using PZT piezoelectric plates in a straight tube resonator

    NASA Astrophysics Data System (ADS)

    Li, Bin; You, Jeong Ho; Kim, Yong-Joe

    2013-05-01

    A novel and practical acoustic energy harvesting mechanism to harvest traveling sound at low audible frequency is introduced and studied both experimentally and numerically. The acoustic energy harvester in this study contains a quarter-wavelength straight tube resonator with lead zirconate titanate (PZT) piezoelectric cantilever plates placed inside the tube. When the tube resonator is excited by an incident sound at its acoustic resonance frequency, the amplified acoustic pressure inside the tube drives the vibration motions of piezoelectric plates, resulting in the generation of electricity. To increase the total voltage and power, multiple PZT plates were placed inside the tube. The number of PZT plates to maximize the voltage and power is limited due to the interruption of air particle motion by the plates. It has been found to be more beneficial to place the piezoelectric plates in the first half of the tube rather than along the entire tube. With an incident sound pressure level of 100 dB, an output voltage of 5.089 V was measured. The output voltage increases linearly with the incident sound pressure. With an incident sound pressure of 110 dB, an output voltage of 15.689 V and a power of 12.697 mW were obtained. The corresponding areal and volume power densities are 0.635 mW cm-2 and 15.115 ?W cm-3, respectively.

  20. Phase diagrams, dielectric response, and piezoelectric properties of epitaxial ultrathin (001) lead zirconate titanate films under anisotropic misfit strains

    NASA Astrophysics Data System (ADS)

    Qiu, Q. Y.; Alpay, S. P.; Nagarajan, V.

    2010-06-01

    We develop a nonlinear thermodynamic model to predict the phase stability of ultrathin epitaxial (001)-oriented ferroelectric PbZr1-xTixO3 (PZT) films with x =1.0, 0.9, 0.8, and 0.7 on substrates which induce anisotropic in-plane strains. The theoretical formalism incorporates the relaxation by misfit dislocations at the film deposition temperature, the possibility of formation of ferroelectric polydomain structures, and the effect of the internal electric field that is generated due to incomplete charge screening at the film-electrode interfaces and the termination of the ferroelectric layer. This analysis allows the development of misfit strain phase diagrams that provide the regions of stability of monodomain and polydomain structures at a given temperature, film thickness, and composition. It is shown that the range of stability for rotational monodomain phase is markedly increased in comparison to the same ferroelectric films on isotropic substrates. Furthermore, the model finds a strong similarity between ultrathin PbTiO3 and relatively thicker PZT films in terms of phase stability. The combinations of the in-plane misfit strains that yield a phase transition sequence that results in a polarization rotation from the c-phase (polarization parallel to the [001] direction in the film) to the r-phase, and eventually to an in-plane polarization parallel to the [110] direction (the aa-phase) is determined to be the path with the most attractive dielectric and piezoelectric coefficients resulting in enhancements of 10 to 100 times in the dielectric permittivity and piezoresponse compared to bulk tetragonal ferroelectrics of the same PZT composition.

  1. Identification of crystalline elastic anisotropy in PZT ceramics from in-situ blocking stress measurements

    SciTech Connect

    Daniel, L.; Hall, D. A.; Withers, P. J.; Webber, K. G.; King, A.

    2014-05-07

    High energy x-ray diffraction measurements of lattice strains were performed on a rhombohedral Lead Zirconate Titanate ceramic (PZT 55-45) under combinations of applied electric field and compressive stress. These measurements allow the construction of blocking stress curves for different sets of crystallographic orientations which reflect the single crystal elastic anisotropy. A micro-mechanical interpretation of the results is then proposed. Assuming cubic symmetry for the crystalline elastic stiffness tensor and isotropy for the macroscopic elastic properties, the elastic properties of the single crystal are extracted from the measured data. An anisotropy ratio close to 0.3 is found (compared to 1 for isotropic materials). The high level of anisotropy found in this work suggests that crystalline elastic anisotropy should not be neglected in the modelling of ferroelectric materials.

  2. Large Stroke Vertical PZT Microactuator With High-Speed Rotational Scanning

    PubMed Central

    Qiu, Zhen; Rhee, Choong-Ho; Choi, Jongsoo; Wang, Thomas D.; Oldham, Kenn R.

    2014-01-01

    A thin-film piezoelectric microactuator using a novel combination of active vertical translational scanning and passive resonant rotational scanning is presented. Thin-film lead-zirconate-titanate unimorph bending beams surrounding a central platform provide nearly 200-?m displacement at 18 V with bandwidth greater than 200 Hz. Inside the platform, a mirror mount, or mirror surface, supported by silicon dioxide spring beams can be excited to resonance by low-voltage; high-frequency excitation of the outer PZT beams. Over ±5.5° mechanical resonance is obtained at 3.8 kHz and ±2 V. The combination of large translational vertical displacements and high-speed rotational scanning is intended to support real-time cross-sectional imaging in a dual axes confocal endomicroscope. PMID:25506187

  3. Fabrication and characterization of micromachined high-frequency tonpilz transducers derived by PZT thick films.

    PubMed

    Zhou, Qifa; Cannata, Jonathan M; Meyer, Richard J; van Tol, David J; Tadigadapa, Srinivas; Hughes, W Jack; Shung, K Kirk; Trolier-McKinstry, Susan

    2005-03-01

    Miniaturized tonpilz transducers are potentially useful for ultrasonic imaging in the 10 to 100 MHz frequency range due to their higher efficiency and output capabilities. In this work, 4 to 10-microm thick piezoelectric thin films were used as the active element in the construction of miniaturized tonpilz structures. The tonpilz stack consisted of silver/lead zirconate titanate (PZT)/lanthanum nickelate (LaNiO3)/silicon on insulator (SOI) substrates. First, conductive LaNiO3 thin films, approximately 300 nm in thickness, were grown on SOI substrates by a metalorganic decomposition (MOD) method. The room temperature resistivity of the LaNiO3 was 6.5 x 10(-6) omega x m. Randomly oriented PZT (52/48) films up to 7-microm thick were then deposited using a sol-gel process on the LaNiO3-coated SOI substrates. The PZT films with LaNiO3 bottom electrodes showed good dielectric and ferroelectric properties. The relative dielectric permittivity (at 1 kHz) was about 1030. The remanent polarization of PZT films was larger than 26 microC/cm2. The effective transverse piezoelectric e31,f coefficient of PZT thick films was about -6.5 C/m2 when poled at -75 kV/cm for 15 minutes at room temperature. Enhanced piezoelectric properties were obtained on poling the PZT films at higher temperatures. A silver layer about 40-microm thick was prepared by silver powder dispersed in epoxy and deposited onto the PZT film to form the tail mass of the tonpilz structure. The top layers of this wafer were subsequently diced with a saw, and the structure was bonded to a second wafer. The original silicon carrier wafer was polished and etched using a Xenon difluoride (XeF2) etching system. The resulting structures showed good piezoelectric activity. This process flow should enable integration of the piezoelectric elements with drive/receive electronics. PMID:15857042

  4. A PZT-based smart aggregate for compressive seismic stress monitoring

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2012-10-01

    A PZT-based smart aggregate (SA) for compressive seismic stress monitoring is proposed in this paper. The proposed SA consists of a piece of PZT (lead zirconate titanate) patch sandwiched between a pair of marble cubes through epoxy. A soft PZT is selected, rendering the SA as a potential actuator in active sensing. Finite element analysis (FEA) was conducted to investigate the stress distribution in the SA under compression, which is used for calculating its sensitivity to compressive stresses. With a commercially available charge amplifier, the frequency response of both the amplitude and the phase shift of the sensing system are investigated by applying the frequency sweep loading scheme on the proposed SA. The frequency ranges from 0.01 to 10 Hz, corresponding to the range of seismic frequency response of most building structures. The alternating load for evaluating SA sensitivity was applied by the servo-hydraulic machine. The lower limit of frequency response is determined to be 0.5 Hz. The depolarization process of the piezoelectric coefficient of the selected PZT material was investigated to decide the load-holding time in calibration tests. The degradation of the piezoelectric coefficient with a series of compressive pre-stresses from 4.8 to 24 MPa was evaluated, and the experimental results showed that the influence from the considered range of pre-stresses is negligible. Using a commercially available charge amplifier, the proposed SA-based sensing system can monitor the seismic stress of low- and middle-rise building structures under moderate earthquakes.

  5. Development of dual PZT transducers for reference-free crack detection in thin plate structures.

    PubMed

    Sohn, Hoon; Kim, Seuno Bum

    2010-01-01

    A new Lamb-wave-based nondestructive testing (NDT) technique, which does not rely on previously stored baseline data, is developed for crack monitoring in plate structures. Commonly, the presence of damage is identified by comparing "current data" measured from a potentially damaged stage of a structure with "baseline data" previously obtained at the intact condition of the structure. In practice, structural defects typically take place long after collection of the baseline data, and the baseline data can be also affected by external loading, temperature variations, and changing boundary conditions. To eliminate the dependence on the baseline data comparison, the authors previously developed a reference-free NDT technique using 2 pairs of collocated lead zirconate titanate (PZT) transducers placed on both sides of a plate. This reference-free technique is further advanced in the present study by the necessity of attaching transducers only on a single surface of a structure for certain applications such as aircraft. To achieve this goal, a new design of PZT transducers called dual PZT transducers is proposed. Crack formation creates Lamb wave mode conversion due to a sudden thickness change of the structure. This crack appearance is instantly detected from the measured Lamb wave signals using the dual PZT transducers. This study also suggests a reference-free statistical approach that enables damage classification using only the currently measured data set. Numerical simulations and experiments were conducted using an aluminum plate with uniform thickness and fundamental Lamb waves modes to demonstrate the applicability of the proposed technique to reference-free crack detection. PMID:20040449

  6. PZT-based active damage detection techniques for steel bridge components

    NASA Astrophysics Data System (ADS)

    Park, Seunghee; Yun, Chung-Bang; Roh, Yongrae; Lee, Jong-Jae

    2006-08-01

    This paper presents the results of experimental studies on piezoelectric lead-zirconate-titanate (PZT)-based active damage detection techniques for nondestructive evaluations (NDE) of steel bridge components. PZT patches offer special features suitable for real-time in situ health monitoring systems for large and complex steel structures, because they are small, light, cheap, and useful as built-in sensor systems. Both impedance and Lamb wave methods are considered for damage detection of lab-size steel bridge members. Several damage-sensitive features are extracted: root mean square deviations (RMSD) in the impedances and wavelet coefficients (WC) of Lamb waves, and the times of flight (TOF) of Lamb waves. Advanced signal processing and pattern recognition techniques such as continuous wavelet transform (CWT) and support vector machine (SVM) are used in the current system. Firstly, PZT patches were used in conjunction with the impedance and Lamb waves to detect the presence and growth of artificial cracks on a 1/8 scale model for a vertical truss member of Seongsu Bridge, Seoul, Korea, which collapsed in 1994. The RMSD in the impedances and WC of Lamb waves were found to be good damage indicators. Secondly, two PZT patches were used to detect damage on a bolt-jointed steel plate, which was simulated by removing bolts. The correlation of the Lamb wave transmission data with the damage classified by in and out of the wave path was investigated by using the TOF and WC obtained from the Lamb wave signals. The SVM was implemented to enhance the damage identification capability of the current system. The results from the experiments showed the validity of the proposed methods.

  7. Development of tough anti cavitation hydrophone by deposition of hydrothermally synthesized lead zirconate titanate poly-crystalline film on reverse surface of titanium front layer

    NASA Astrophysics Data System (ADS)

    Takeuchi, Shinichi; Ishikawa, Mutsuo; Kawashima, Norimichi; Uchida, Takeyoshi; Yoshioka, Masahiro; Kikuchi, Tsuneo; Okada, Nagaya; Kurosawa, Minoru; Kuribayashi

    2012-05-01

    It is difficult to measure the high intensity ultrasound field with generation of acoustic cavitaion, since the electrode of hydrophone will be damaged by erosion and acoustic cavitation. Therefore, we developed the original miniature hydrophone by using hydrothermally synthesized lead zirconate titanate poly-crystalline film deposited on a reverse surface of a titanium film front layer as protection layer from damage by acoustic cavitation and erosion. Our hydrophone could be used to measure the high intensity ultrasound field with generation of acoustic cavitation such as focal area of 1.6 MHz HIFU treatment equipment and in a vessel of a 47 kHz ultrasound cleaner without any damage. However, we observed the output waveform of the hydrophone without nonlinear distortion in spite of measurement in high intensity ultrasound field like focal area of 1.6 MHz HIFU treatment equipment. We considered on the cause of above problem and its improving methods by computer simulation with MASON's equivalent circuit and one dimensional acoustic transmission model for the titanium front layer. As results, it was found that the cause of above problem was decrease of its receiving sensitivity in higher frequency region. Furthermore, we could propose two types of structure of hydrophones with improved frequency characteristics of receiving sensitivities. One type of hydrophone has titanium front layer thinner than 5?m. Another type has titanium front layer with thickness of 50?m and backing material with specific acoustic impedance of about 24 MRayl.

  8. Investigations on structural and multiferroic properties of artificially engineered lead zirconate titanate-cobalt iron oxide layered nanostructures

    NASA Astrophysics Data System (ADS)

    Ortega Achury, Nora Patricia

    Mutiferroics are a novel class of next generation multifunctional materials, which display simultaneous magnetic, electric, and ferroelastic ordering, have drawn increasing interest due to their multi-functionality for a variety of device applications. Since, very rare single phase materials exist in nature this kind of properties, an intensive research activity is being pursued towards the development of new engineered materials with strong magneto-electric (ME) coupling. In the present investigation, we have fabricated polycrystalline and highly oriented PbZr0.53,Ti0.47O3--CoFe 2O4 (PZT/CFO) artificially multilayers (MLs) engineered nanostructures thin films which were grown on Pt/TiO2/SiO2/Si and La 0.5Sr0.5CoO3 (LSCO) coated (001) MgO substrates respectively, using the pulsed laser deposition technique. The effect of various PZT/CFO sandwich configurations having 3, 5, and 9 layers, while maintaining similar total PZT and CFO thickness, has been systematically investigated. The first part of this thesis is devoted to the analysis of structural and microstructure properties of the PZT/CFO MLs. X-ray diffraction (XRD) and micro Raman analysis revealed that PZT and CFO were in the perovskite and spinel phases respectively in the all layered nanostructure, without any intermediate phase. The TEM and STEM line scan of the ML thin films showed that the layered structure was maintained with little inter-diffusion near the interfaces at nano-metric scale without any impurity phase, however better interface was observed in highly oriented films. Second part of this dissertation was dedicated to study of the dielectric, impedance, modulus, and conductivity spectroscopies. These measurements were carried out over a wide range of temperatures (100 K to 600 K) and frequencies (100 Hz to 1 MHz) to investigate the grain and grain boundary effects on electrical properties of MLs. The temperature dependent dielectric and loss tangent illustrated step-like behavior and relaxation peaks near the step-up characteristic respectively. The Cole-Cole plots indicate that the most of the dielectric response came from the bulk (grains) MLs below 300 K, whereas grain boundaries and electrode-MLs effects prominent at elevated temperature. The dielectric loss relaxation peaks shifted to higher frequency side with increase in temperature, finally above 300 K, it went out experimental frequency window. Our Cole-Cole fitting of dielectric loss spectra indicated marked deviation from the ideal Debye type of relaxation which is more prominent at elevated temperature. Master modulus spectra support the observation from impedance spectra, it also indicate that the difference between C g and Cgb are higher compared to polycrystalline MLs indicating less effects of grain boundary in highly oriented MLs. We have explained these electrical properties of MLs by Maxwell-Wagner type contributions arising from the interfacial charge at the interface of the MLs structure. Three different types of frequency dependent conduction process were observed at elevated temperature (>300 K), which well fitted with the double power law, sigma(o) = sigma(0) + A 1on1 + A 2on2, it indicates conduction at: Low frequency (<1 kHz) may be due to long range ordering (frequency independent), mid frequency (<10 kHz) may be due to short range hopping, and high frequency (<1 MHz) due to the localized relaxation hopping mechanism. The last part of the thesis is devoted to the study of the multiferroic and magnetoelectric properties of the ML thin films. Both polycrystalline and highly oriented films showed well saturated ferroelectric and ferromagnetic hysteresis loops at room temperature. Temperature dependence of ferroelectric properties showed that polarization slowly decreases from 300 K to 200 K, with complete collapse of polarization at ˜ 100 K, but there was complete recovery of the polarization during heating, which was repeatable over many different experiments. At the same time, in the same temperature interval the remanent magnetization of the MLs showed slo

  9. Emission, plasma formation, and brightness of a PZT ferroelectric cathode

    SciTech Connect

    Sampayan, S.; Caporaso, G.; Trimble, D.; Westenskow, G.

    1995-04-27

    We have measured an 36-A-cm{sup {minus}2} current emission density over the surface area of an 11.4-cm{sup 2}-area Lead-Titanate- Zirconate (PZT) ferroelectric cathode with a pulsed anode-cathode (A-K) potential of 50 kV. We have also observed currents above those predicted by classical Child-Langmuir formula for a wide variety of cases. Since a plasma within the A-K gap could also lead to increase current emission we are attempting to measure the properties of the plasma near the cathode surface at emission time. In other measurements, we have observed strong gap currents in the absence of an A-K potential. Further, we continue to make brightness measurements of the emitted beam and observe spatially non-uniform emission and large shot-to-shot variation. Measurements show individual beamlets with a brightness as high 10{sup 11} Am{sup {minus}2} rad{sup {minus}2}.

  10. A PZT-based smart aggregate for seismic shear stress monitoring

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2013-06-01

    A lead zirconate titanate (PZT)-based smart aggregate (SA) is proposed for seismic shear stress monitoring in concrete structures. This SA uses a d15-mode PZT as the sensing element. A calibration test is designed in which a cyclic shear stress with a dominant frequency of the earthquake response spectrum is applied on the two opposite sides of the proposed SA using a specially designed loading mold. The test is repeated on six copies of the proposed SA. The maximum applied shear stress is larger than the shear strength of ordinary concrete to allow measurements during failure. The output voltage of the SA is experimentally verified as varying linearly with the applied stress in the loading range. The sensitivity of the proposed SA to the applied stress under the given boundary conditions is examined. The calibrated sensitivity value is then compared with the calculated value, which is obtained by computing the stress distribution in the SA using finite element analysis (FEA). The calculated values and the calibrated values are approximately the same, indicating that the established finite element (FE) model is reliable. Monotonic loading is also applied on the proposed SA to induce cracks between the SA and the loading mold, and the SA’s response to cracking processes is examined. It is found that the proposed SA underestimates the cracking process. This study demonstrates that the proposed SA can be used in monitoring the overall shear stress development process in concrete during a seismic event.

  11. Powering low-power implants using PZT transducer discs operated in the radial mode

    NASA Astrophysics Data System (ADS)

    Sanni, Ayodele; Vilches, Antonio

    2013-11-01

    This paper reports experimental results that are used to compare operation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic discs operated in the radial mode. The devices are driven to radially vibrate at their lowest fundamental resonant frequency and thus transmit and receive power when immersed in a liquid phantom. A number of 1 mm × 10 mm (thickness × diameter) PZT discs are characterized experimentally within a propagation tank and results discussed. On the basis of these measured characteristics, a novel application is developed and reported for the first time. This consists of a tuned LC resonator circuit which is used at the receiving disc to maximize sensitivity as well as a Seiko start-up IC S-882Z which is employed to charge a capacitor that drives a PIC microcontroller (?C) once the voltage exceeds 2 V DC. We show that a mean input power of 486 mW RMS results in 976 ?W RMS received over a range of 80 mm and that this is sufficient to periodically (every 60 s) power the ?C to directly drive a red LED for 5 ms with a current of 4.8 mA/flash. This approach is suitable for low-power, periodically activated analogue bio-implant applications.

  12. Fatigue Response of a PZT Multilayer Actuator under High-Field Electric Cycling with Mechanical Preload

    SciTech Connect

    Wang, Hong; Wereszczak, Andrew A; Lin, Hua-Tay

    2009-01-01

    An electric fatigue test system has been developed for piezoelectric actuator with a mechanical loading capability. Fatigue responses of a lead zirconate titanate (PZT) multilayer actuator (MLA) with a plate-through electrode configuration have been studied under an electric field (1.7 times that of a coercive field of PZT material) and a concurrent mechanical preload (30.0 MPa). A total of 1.0x10^9 cycles were carried out. Variations in charge density and mechanical strain under a high electric field and constant mechanical loads were observed during the fatigue test. The dc and the first harmonic (at 10 Hz) dielectric and piezoelectric coefficients were subsequently characterized by using FFT (Fast Fourier Transformation). It has been observed that both the dielectric and the piezoelectric coefficients underwent a monotonic decrease prior to 2.86x10^8 cycles under the relevant preload, and then fluctuated to a certain extent. Both the dielectric loss tangent and the piezoelectric loss tangent also exhibited the fluctuations after a certain amount of drop but at different levels relative to the pre-fatigue. And finally, the results were discussed with respect to domain wall mobility, microcracking, and other pre-existing anomalies.

  13. Direct strain energy harvesting in automobile tires using piezoelectric PZT-polymer composites

    NASA Astrophysics Data System (ADS)

    van den Ende, D. A.; van de Wiel, H. J.; Groen, W. A.; van der Zwaag, S.

    2012-01-01

    Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical failure or depolarization, especially at elevated temperatures. In this work, three kinds of ceramic-polymer composite piezoelectric materials were evaluated and compared against state-of-the-art piezoelectric materials. The new composites are unstructured and structured composites containing granular lead zirconate titanate (PZT) particles or PZT fibers in a polyurethane matrix. The composites were used to build energy harvesting patches which were attached to a tire and tested under simulated rolling conditions. The energy density of the piezoelectric ceramic-polymer composite materials is initially not as high as that of the reference materials (a macro-fiber composite and a polyvinylidene fluoride polymer). However, the area normalized power output of the composites after temperature and strain cycling is comparable to that of the reference devices because the piezoelectric ceramic-polymer composites did not degrade during operation.

  14. Preparation and characterization of sol-gel-derived PZT thin films for microactuators

    NASA Astrophysics Data System (ADS)

    Wang, Zhanjie; Maeda, Ryutaro; Kikuchi, Kaoru M.

    1999-03-01

    Crack-free ferroelectric thin films of lead zirconate titanate with thickness of 3 micrometers for microactuators were fabricated using Sol-Gel spin-coating onto Pt/Ti/SiO2/Si substrates. The precursor solution was prepared from lead acetate, zirconium-n-propoxide and titanium tetraisopropoxide. 2-propanol was used as the solvent. The crystalline phase as well as preferred orientation in the PZT films were investigated using x-ray diffraction analysis. The microstructure and composition of the films were studied by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy, respectively. The well-crystallized perovskite phase and the preferred orientations in the direction of the (100) plane were obtained using the heat treatment for dry at 120 degrees C, for pyrolysis at 300 degrees C and for crystallization at 600 degrees C. The prepared films showed nanometer grains with smooth and uniform surface. The dielectric constants and loss values of these films measured at 1 kHz were approximately 1250 and 0.04, respectively, while the remnant polarization and the coercive field were 45.5 (mu) C/cm2 and 58.5 kV/cm. Our results suggest that fabrication of good structural quality PZT films of a few micrometers thick for use in micro actuators is possible.

  15. Optical amplification in disordered electrooptic Tm{sup 3+} and Ho{sup 3+} codoped lanthanum-modified lead zirconate titanate ceramics and study of spectroscopy and communication between cations

    SciTech Connect

    Zhao, Hua; Zhang, Kun; Xu, Long; Sun, Fankui; Zhang, Jingwen; Chen, Xuesheng; Li, Kewen K.

    2014-02-21

    Rare earth doped electro-optic (EO) ceramics of lanthanum-modified lead zirconate titanate (PLZT) are promising in building multifunctional optical devices, by taking advantage of both EO effect and optical activity. In this work, the combination of the measured spectra of absorption and photoluminescence, the fluorescent decay, the calculated Judd-Ofelt parameters, and measured single pass gain in Tm{sup 3+}, Ho{sup 3+} codoped PLZT ceramics have marked them out as promising gain media in building electrically controllable lasers/optical amplifiers and other multifunctional devices. Optical energy storage was also observed in the optical amplification dynamics.

  16. Clamping effect on the piezoelectric responses of screen-printed low temperature PZT/Polymer films on flexible substrates

    NASA Astrophysics Data System (ADS)

    Almusallam, A.; Yang, K.; Zhu, D.; Torah, R. N.; Komolafe, A.; Tudor, J.; Beeby, S. P.

    2015-11-01

    This paper introduces a new flexible lead zirconate titanate (PZT)/polymer composite material that can be screen-printed onto fabrics and flexible substrates, and investigates the clamping effect of these substrates on the characterization of the piezoelectric material. Experimental results showed that the optimum blend of PZT/polymer binder with a weight ratio of 12:1 provides a dielectric constant of 146. The measured value of the piezoelectric coefficient d33 was found to depend on the substrate used. Measured d33clp values of 70, 40, 36 pC N?1 were obtained from the optimum formulation printed on Polyester–cotton with an interface layer, Kapton and alumina substrates, respectively. The variation in the measured d33clp values occurs because of the effect of the mechanical boundary conditions of the substrate. The piezoelectric film is mechanically bonded to the surface of the substrate and this constrains the film in the plane of the substrate (the 1-direction). This constraint means that the perpendicular forces (applied in the 3-direction) used to measure d33 introduce a strain in the 1-direction that produces a charge of the opposite polarity to that induced by the d33 effect. This is due to the negative sign of the d31 coefficient and has the effect of reducing the measured d33 value. Theoretical and experimental investigations confirm a reduction of 13%, 50% and 55% in the estimated freestanding d33fs values (80 pC N?1) on Polyester–cotton, Kapton and alumina substrates, respectively. These results demonstrate the effect of the boundary conditions of the substrate/PZT interface on the piezoelectric response of the PZT/polymer film and in particular the reduced effect of fabric substrates due to their lowered stiffness.

  17. Measurement of effective piezoelectric coefficients of PZT thin films for energy harvesting application with interdigitated electrodes.

    PubMed

    Chidambaram, Nachiappan; Mazzalai, Andrea; Muralt, Paul

    2012-08-01

    Interdigitated electrode (IDE) systems with lead zirconate titanate (PZT) thin films play an increasingly important role for two reasons: first, such a configuration generates higher voltages than parallel plate capacitor-type electrode (PPE) structures, and second, the application of an electric field leads to a compressive stress component in addition to the overall stress state, unlike a PPE structure, which results in tensile stress component. Because ceramics tend to crack at relatively moderate tensile stresses, this means that IDEs have a lower risk of cracking than PPEs. For these reasons, IDE systems are ideal for energy harvesting of vibration energy, and for actuators. Systematic investigations of PZT films with IDE systems have not yet been undertaken. In this work, we present results on the evaluation of the in-plane piezoelectric coefficients with IDE systems. Additionally, we also propose a simple and measurable figure of merit (FOM) to analyze and evaluate the relevant piezoelectric parameter for harvesting efficiency without the need to fabricate the energy harvesting device. Idealized effective coefficients e(IDE) and h(IDE) are derived, showing its composite nature with about one-third contribution of the transverse effect, and about two-thirds contribution of the longitudinal effect in the case of a PZT film deposited on a (100)-oriented silicon wafer with the in-plane electric field along one of the <011> Si directions. Randomly oriented 1-?m-thick PZT 53/47 film deposited by a sol-gel technique, was evaluated and yielded an effective coefficient e(IDE) of 15 C·m(-2). Our FOM is the product between effective e and h coefficient representing twice the electrical energy density stored in the piezoelectric film per unit strain deformation (both for IDE and PPE systems). Assuming homogeneous fields between the fingers, and neglecting the contribution from below the electrode fingers, the FOM for IDE structures with larger electrode gap is derived to be twice as large as for PPE structures, for PZT-5H properties. The experiments yielded an FOM of the IDE structures of 1.25 × 10(10) J/m(3) and 14 mV/? strain. PMID:22899110

  18. Elimination of PZT thin film breakage caused by electric current arcing and intrinsic differential strains during poling

    E-print Network

    AlSaeed, Abdulelah (Abdulelah Ibrahim)

    2012-01-01

    Historically, substrate breakage during the poling process has been responsible for a 2% yield loss for a contract manufacturer specializing in volume production of lead zirconate titatate (PZT) thin film devices. In this ...

  19. Low-temperature growth of ferroelectric lead zirconate titanate thin films using the magnetic field of low power 2.45 GHz microwave irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Z. J.; Cao, Z. P.; Otsuka, Y.; Yoshikawa, N.; Kokawa, H.; Taniguchi, S.

    2008-06-01

    Pb(ZrxTi1-x)O3 (PZT) thin films were coated on Pt /Ti/SiO2/Si substrates by the sol-gel method and then crystallized by using the magnetic field of 2.45GHz microwave irradiation. The elevated temperature generated by microwave irradiation used to obtain the perovskite phase was only 450°C, which is significantly lower than that of conventional thermal processing. The PZT films crystallized by microwave irradiation showed similar ferroelectric properties to those of the films crystallized by conventional thermal processing at 600°C. It is clear that single-mode 2.45GHz microwave irradiation in the microwave magnetic field is effective for obtaining perovskite PZT thin films at low temperatures.

  20. Local piezoelectric behavior in PZT-based thin films for ultrasound transducers

    NASA Astrophysics Data System (ADS)

    Griggio, Flavio

    Piezoelectric microelectromechanical systems (MEMS) are currently used in inkjet printers and precision resonators; numerous additional applications are being investigated for sensors, low-voltage actuators, and transducers. This work was aimed at improving piezoelectric MEMS by taking two approaches: 1) identifying factors affecting the piezoelectric response of ferroelectric thin films and 2) demonstrating integration of these films into a high frequency array transducer. It was found that there are several key factors influencing the piezoelectric response of thin films for a given material composition. First, large grain size improves the piezoelectric response. This was demonstrated using chemical solution deposited lead nickel niobate -- lead zirconate titanate (0.3)Pb(Ni 0.33Nb0.67)O3 - (0.7)Pb(Zr0.45Ti 0.55O3), (PNN-PZT) ferroelectric thin films. It was shown that this composition allows greater microstructural control than does PZT. Dielectric permittivities ranging from 1350 to 1520 and a transverse piezoelectric coefficient e31,f as high as -- 9.7 C/m 2 were observed for films of about 0.25 mum in thickness. The permittivity and piezoelectric response as well as extrinsic contributions to the dielectric constant increased by 14 and 12 % respectively for samples with grain sizes ranging from 110 to 270 nm. A second factor influencing the piezoelectric response is film composition with respect to the morphotropic phase boundary (MPB). The composition dependence of the dielectric and piezoelectric nonlinearities was characterized in epitaxially grown (0.3)Pb(Ni0.33Nb0.67)O3-(0.7)Pb(Zr xTi1-xO3) thin films deposited on SrTiO 3 to minimize the influence of large-angle grain boundaries. Tetragonal, MPB and rhombohedral films were prepared by changing the Zr/Ti ratio. The largest dielectric and piezoelectric nonlinearities were observed for the rhombohedral sample; this resulted from a higher domain wall mobility due to a smaller ferroelectric distortion and superior crystal quality. Thirdly, changes in the mechanical boundary conditions experienced by a ferroelectric thin film were found to influence both the properties and the length scale for correlated motion of domain walls. Microfabrication was employed to release the PZT films from the Si substrate. Nonlinear piezoelectric maps, by band excitation piezoforce microscopy, showed formation of clusters of higher nonlinear activities of similar size for clamped PZT films with different microstructures. However PZT films that had been released from the Si substrate showed a distinct increase in the correlation length associated with coupled domain wall motion, suggesting that the local mechanical boundary conditions, more than microstructure or composition govern the domain wall dynamics. Release of both the local and the global stress states in films produced dielectric nonlinearities comparable to those of bulk ceramics. The second research direction was targeted at demonstrating the functionality of a one dimensional transducer array. A diaphragm geometry was used for the transducer arrays in order to benefit from the unimorph-type displacement of the PZT-SiO2 layers. For this purpose, the PZT and remaining films in the stack were patterned using reactive ion etching and partially released from the underlying silicon substrate by XeF2 etching from the top. Admittance measurements on the fabricated structures showed resonance frequencies at ˜40 MHz for a 80 mum diameter-wide diaphragms with a PZT thickness of 1.74 mum. In-water transmit and receive functionalities were demonstrated. A bandwidth on receive of 80 % centered at 40 MHz was determined during pitch-mode tests.

  1. Real-Time, Label-Free, All-Electrical Detection of Salmonella typhimurium Using Lead Zirconate Titanate/Gold-Coated Glass Cantilevers at any Relative Humidity

    PubMed Central

    Zhu, Qing; Shih, Wan Y.; Shih, Wei-Heng

    2007-01-01

    We have examined non-insulated PZT/gold-coated glass cantilevers for real-time, label-free detection of Salmonella t. by partial dipping at any relative humidity. The PZT/gold-coated glass cantilevers were consisted of a 0.127 mm thick PZT layer about 0.8 mm long, 2 mm wide bonded to a 0.15 mm thick gold-coated glass layer with a 3.0 mm long gold-coated glass tip for detection. We showed that by placing the water level at the nodal point, about 0.8 mm from the free end of the gold-glass tip, there was a 1-hr window in which the resonance frequency was stable despite the water level change by evaporation at 20% relative humidity or higher. By dipping the cantilevers to their nodal point, we were able to do real-time, label-free detection without background resonance frequency corrections at any relative humidity. The partially dipped PZT/gold-coated glass cantilever exhibited mass detection sensitivity, ?m/?f = ?5×10?11g/Hz, and a detection concentration sensitivity, 5×103 cells/ml in 2 ml of liquid, which was about two orders of magnitude lower than that of a 5 MHz QCM. It was also about two orders of magnitude lower than the infection dosage and one order of magnitude lower that the detection limit of a commercial Raptor sensor. PMID:22872784

  2. Micromachined bulk PZT tissue contrast sensor for fine needle aspiration biopsy.

    PubMed

    Li, Tao; Gianchandani, Roma Y; Gianchandani, Yogesh B

    2007-02-01

    This paper describes a micromachined piezoelectric sensor, integrated into a cavity at the tip of a biopsy needle, and preliminary experiments to determine if such a device can be used for real-time tissue differentiation, which is needed for needle positioning guidance during fine needle aspiration (FNA) biopsy. The sensor is fabricated from bulk lead zirconate titanate (PZT), using a customized process in which micro electro-discharge machining is used to form a steel tool that is subsequently used for batch-mode ultrasonic micromachining of bulk PZT ceramic. The resulting sensor is 50 microm thick and 200 microm in diameter. It is placed in the biopsy needle cavity, against a steel diaphragm which is 300 microm diameter and has an average thickness of 23 microm. Devices were tested in materials that mimic the ultrasound characteristics of human tissue, used in the training of physicians, and with porcine fat and muscle tissue. In both schemes, the magnitude and frequency of an electrical impedance resonance peak showed tissue-specific characteristics as the needle was inserted. For example, in the porcine tissue, the impedance peak frequency changed approximately 13 MHz from the initial 163 MHz, and the magnitude changed approximately 1600 Omega from the initial 2100 Omega, as the needle moved from fat to muscle. Samples including oils and saline solution were tested for calibration, and an empirical tissue contrast model shows an approximately proportional relationship between measured frequency shift and sample acoustic impedance. These results suggest that the device can complement existing methods for guidance during biopsies. PMID:17268619

  3. Characterization of a Pt-core PZT fiber/Al matrix composite

    NASA Astrophysics Data System (ADS)

    Richeson, M.; Erturun, U.; Waxman, R.; Mossi, K.; Kunikata, J.; Asanuma, H.

    2010-04-01

    The objective of this study is to design and characterize a piezoelectric composite and evaluate its suitability for viscosity-measuring applications, i.e., monitoring the coagulation rate of blood. The composite is manufactured of a platinum-core lead zirconate titanate (PZT) fiber inserted into an aluminum matrix. This study characterizes the described composite by testing its impedance, capacitance, voltage sensitivity response to vibrational inputs, and deformation due to electrical input. As actuators, different voltage inputs are fed into the probes and displacement is measured with results on the range of nanometers. As sensors, the devices are used to monitor cantilever beam vibrations. The probe's response is in the mV range and follows the same pattern as an accelerometer. Additional tests in air, water, and deionized water are carried out to evaluate the sensor's suitability for measuring viscosity using two probes: one as an actuator and the other as a sensor. Results of the gain and phase between the two probes indicate that the phase shift may be used as an indicator of viscosity changes. The first significant phase shift was measured as 2.45, 2.77, and 4.065x107Hz, for water, air, and oil, respectively, which is directly proportional to the kinematic viscosity of each fluid.

  4. Array lead zirconate titanate?glass piezoelectric microcantilevers for real-time detection of Bacillus anthracis with 10 spores?ml sensitivity and 1?1000 selectivity in bacterial mixtures

    PubMed Central

    McGovern, John-Paul; Shih, Wei-Heng; Rest, Richard F.; Purohit, Mitali; Mattiucci, Mark; Pourrezaei, Kambiz; Onaral, Banu; Shih, Wan Y.

    2009-01-01

    An array of three identical piezoelectric microcantilever sensors (PEMSs) consisting of a lead zirconate titanate layer bonded to a glass layer was fabricated and examined for simultaneous, in situ, real-time, all-electrical detection of Bacillus anthracis (BA) spores in an aqueous suspension using the first longitudinal extension mode of resonance. With anti-BA antibody immobilized on the sensor surfaces all three PEMS exhibited identical BA detection resonance frequency shifts at all tested concentrations, 10–107 spores?ml with a standard deviation of less than 10%. The detection concentration limit of 10 spores?ml was about two orders of magnitude lower than would be permitted by flexural peaks. In blinded-sample testing, the array PEMS detected BA in three samples containing BA: (1) 3.3×103 spores?ml, (2) a mixture of 3.3×103 spores?ml and 3.3×105S. aureus (SA) and P. aeruginosa (PA) per ml, and (3) a mixture of 3.3×103 spores?ml with 3.3×106 SA+PA?ml. There was no response to a sample containing only 3.3×106 SA+PA?ml. These results illustrate the sensitivity, specificity, reusability, and reliability of array PEMS for in situ, real-time detection of BA spores. PMID:20059167

  5. Array lead zirconate titanate/glass piezoelectric microcantilevers for real-time detection of Bacillus anthracis with 10 spores/ml sensitivity and 1/1000 selectivity in bacterial mixtures

    NASA Astrophysics Data System (ADS)

    McGovern, John-Paul; Shih, Wei-Heng; Rest, Richard F.; Purohit, Mitali; Mattiucci, Mark; Pourrezaei, Kambiz; Onaral, Banu; Shih, Wan Y.

    2009-12-01

    An array of three identical piezoelectric microcantilever sensors (PEMSs) consisting of a lead zirconate titanate layer bonded to a glass layer was fabricated and examined for simultaneous, in situ, real-time, all-electrical detection of Bacillus anthracis (BA) spores in an aqueous suspension using the first longitudinal extension mode of resonance. With anti-BA antibody immobilized on the sensor surfaces all three PEMS exhibited identical BA detection resonance frequency shifts at all tested concentrations, 10-107 spores/ml with a standard deviation of less than 10%. The detection concentration limit of 10 spores/ml was about two orders of magnitude lower than would be permitted by flexural peaks. In blinded-sample testing, the array PEMS detected BA in three samples containing BA: (1) 3.3×103 spores/ml, (2) a mixture of 3.3×103 spores/ml and 3.3×105 S. aureus (SA) and P. aeruginosa (PA) per ml, and (3) a mixture of 3.3×103 spores/ml with 3.3×106 SA+PA/ml. There was no response to a sample containing only 3.3×106 SA+PA/ml. These results illustrate the sensitivity, specificity, reusability, and reliability of array PEMS for in situ, real-time detection of BA spores.

  6. Magnetoelectric effect in layered ferrite/PZT composites. Study of the demagnetizing effect on the magnetoelectric behavior

    NASA Astrophysics Data System (ADS)

    Loyau, V.; Morin, V.; Chaplier, G.; LoBue, M.; Mazaleyrat, F.

    2015-05-01

    We report the use of high magnetomechanical coupling ferrites in magnetoelectric (ME) layered composites. Bilayer samples combining (Ni0.973 Co0.027)1-xZnxFe2O4 ferrites (x = 0-0.5) synthesized by non conventional reactive Spark Plasma Sintering and commercial lead zirconate titanate (PZT) were characterized in term of ME voltage coefficients measured at sub-resonant frequency. Strong ME effects are obtained and we show that an annealing at 1000 °C and a quenching in air improve the piezomagnetic behavior of Zn-rich compositions. A theoretical model that predicts the ME behavior was developed, focusing our work on the demagnetizing effects in the transversal mode as well as the longitudinal mode. The model shows that: (i) high ME coefficients are obtained when ferrites with high magnetomechanical coupling are used in bilayer ME composites, (ii) the ME behavior in transversal and longitudinal modes is quite similar, and differences in the shapes of the ME curves are mainly due the demagnetizing effects, (iii) in the transversal mode, the magnetic field penetration depends on the ferrite layer thickness and the ME coefficient is affected accordingly. The two later points are confirmed by measurements on ME samples and calculations. Performances of the ME composites made with high magnetomechanical coupling ferrites are compared to those obtained using Terfenol-D materials in the same conditions of size, shape, and volume ratio. It appears that a ferrite with an optimized composition has performances comparable to those obtained with Terfenol-D material. Nevertheless, the fabrication processes of ferrites are quite simpler. Finally, a ferrite/PZT based ME composite was used as a current sensor.

  7. A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

    PubMed Central

    Choi, Jongsoo; Qiu, Zhen; Rhee, Choong-Ho; Wang, Thomas; Oldham, Kenn

    2014-01-01

    A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, ?x, ?y) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 ?m of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 ?m of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 ?m, which approaches the desired imaging resolution, 5 ?m, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system. PMID:25506131

  8. High performance Au/PZT/TiOxNy/Si MFIS structure for next generation ferroelectric memory applications

    NASA Astrophysics Data System (ADS)

    Sharma, Deepak K.; Khosla, Robin; Sharma, Satinder K.

    2015-05-01

    The Metal-Ferroelectric-Insulator-Semiconductor (MFIS) capacitors with thin 20 nm lead zirconate titanate (PZT) and titanium oxynitride (TiOxNy) buffer layer were fabricated by RF magnetron sputtering technique and characterized. TiOxNy as a buffer layer deposited for the first time for MFIS application at different thicknesses and fabricated structure was found to exhibit excellent electrical characteristics at 14 nm TiOxNy. Memory window of 0.4 V was found at low sweep voltage of ± 3 V which increases to 1.8 V at sweep voltage of ±14 V indicating multilevel data storage. Moreover the fabricated structure possesses low leakage current density of ˜4 µA/cm2 at 36 nm TiOxNy which increases to 12 µA/cm2 at 4 nm TiOxNy at 5 V, reasonable limit. Furthermore, the fabricated structure possesses outstanding data retention capability at 14 nm TiOxNy; the high and low capacitance becomes constant after few seconds and clearly distinguishable for 1h and 30 min. This shows that proposed MFIS structure is suitable for high performance ferroelectric memory applications.

  9. Processing of PZT ceramics: aqueous mixing procedures for powder consolidation

    SciTech Connect

    Bunker, B.C.; Lamppa, D.L.; Moore, R.H.

    1986-02-01

    Inhomogeneities in chemical compositions and microstructures can result in lot-to-lot variations in the charge release characteristics of ferroelectric lead-zirconate-titanate ceramics. One source of inhomogeneity is agglomeration and selective sedimentation which occurs during aqueous mixing of the constituent oxides. Procedures using electrostatic and steric stabilization of oxide powders were developed for fabricating homogeneous powder compacts. Use of lead carbonate instead of lead oxide minimizes problems encountered using various slurry stabilization techniques.

  10. Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

    NASA Astrophysics Data System (ADS)

    James, N. K.; Lafont, U.; van der Zwaag, S.; Groen, W. A.

    2014-05-01

    Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT-Zn ionomer composites have better piezoelectric properties compared to PZT-EMAA composites. The static and fatigue properties of the composites were investigated. The PZT-Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing.

  11. Scalable synthesis of morphotropic phase boundary lead zirconium titanate nanowires for energy harvesting.

    PubMed

    Zhou, Zhi; Tang, Haixiong; Sodano, Henry A

    2014-12-01

    Lead zirconium titanate (PZT) nanowires are synthesized using a scalable two-step hydrothermal reaction. The piezo-electric coupling coefficient of the PZT NWs shows the highest value for PZT nano-wires in the literature (80 ± 5 pm/V). A PZT-NW-based nanocomposite is fabri-cated to demonstrate an energy-harvesting application with an open-circuit voltage up to 7 V and a power density up to 2.4 ?W/cm(3) . PMID:25312483

  12. Biologically functionalized nanochannels on ferroelectric lead zirconium titanate surfaces.

    SciTech Connect

    Ocola, L. E.; Pan, W. C.; Kuo, M.; Tirumala, V. R.; Reiss, B. D.; Firestone, M. A.; Illinois Mathematics and Science Academy

    2005-01-01

    We recently started a program at Argonne to exploit patterned, polarizable ferroelectric surfaces, such as lead zirconium titanate (PZT), as a means to create field-responsive inorganic-biomolecule interfaces to study and manipulate biomatter on surfaces. In this paper we will discuss the integration of nanochannels on the surface of PZT films and their selective functionalization to create nanovalves to control nanofluidic flow. Microfluidic devices have been fabricated using a variety of methods, ranging from thermal decomposition of buried patterned channels, to fabricating trenches via plasma etch or hot embossing followed by trench capping. Our work focuses on an alternative method by using a bilayer resist in an inverted configuration normally used for T- and Gamma- gate fabrication. This method is capable of yielding sub-100 nm nanochannels with high aspect ratios and sub-500nm alignment. We have recently demonstrated that the polarization hysteresis loop of PZT is the same before and after exposure to an aqueous environment. This opens the possibility of selective surface modification of PZT via coupling of a wide range of biomolecules (e.g., peptides, proteins) and the use of the electric-field-responsive properties of PZT to manipulate the function (e.g., orientation) of the tethered biomolecules. We have used phage display techniques to evolve specific peptide motifs that selectively bind to PZT. The optimum heptapeptide that facilitates both the attachment of functional biological molecules to the surface of PZT has been identified.

  13. The effects of non-hydrostatic compression and applied electric field on the electromechanical behavior of poled PZT 95/5-2Nb ceramic during the F{sub R1} {yields} A{sub 0} polymorphic phase transformation

    SciTech Connect

    Zeuch, D.H.; Montgomery, S.T.; Zimmerer, D.J.

    1995-10-01

    We conducted hydrostatic and constant-stress-difference (CSD) experiments at room temperature on two different sintered batches of poled, niobium-doped lead-zirconate-titanate ceramic (PZT 95/5-2Nb). The objective of this test plan was to quantify the effects of nonhydrostatic stress on the electromechanical behavior of the ceramic during the ferroelectric, rhombohedral {yields} antiferroelectric, orthorhombic (FE {yields} AFE) phase transformation. We also performed a series of hydrostatic and triaxial compression experiments in which a 1000 V potential was applied to poled specimens to evaluate any effect of a sustained bias on the transformation. As we predicted from earlier tests on unpoled PZT 95/5-2Nb, increasing the stress difference up to 200 MPa (corresponding to a maximum resolved shear stress of 100 MPa) decreases the mean stress and confining pressure at which the transformation occurs by 25--33%, for both biased and unbiased conditions. This same stress difference also retards the rate of transformation at constant pressurization rate, resulting in reductions of up to an order of magnitude in the rate of charge release and peak voltage attained in our tests. This shear stress-voltage effect offers a plausible, though qualitative explanation for certain systematic failures that have occurred in neutron generator power supplies when seemingly minor design changes have been made. Transformation strains in poled ceramic are anisotropic (differing by up to 33%) in hydrostatic compression, and even more anisotropic under non-hydrostatic stress states. Application of a 1000 V bias appears to slightly increase (by {le}2%) the transformation pressure for poled ceramic, but evidence for this conclusion is weak.

  14. Novel lead-free piezoelectric ceramics in the solid solution (1-x) bismuth iron oxide-barium titanate

    NASA Astrophysics Data System (ADS)

    Leontsev, Serhiy

    Piezoelectric materials are widely used in many areas of science and technology due to their electromechanical properties. The transformation of mechanical energy into electrical signals and vice versa based on the piezoelectric effect has led to the development of sensor devices and piezoelectric actuators used in accelerometers, pressure and vibration meters, micropositioning devices, ultrasound generators, motors etc. The most technologically important piezoelectric material is lead zirconate titanate PbZrO3-PbTiO3 (PZT), however, the commercial manufacture and application of PZT as a lead-based material represent serious health hazards. The need to reduce environmental contamination by lead-based substances has created the current drive to develop alternative lead-free piezoelectric materials. The present work describes a detailed investigation of the novel multifunctional ceramic material in a solid solution of bismuth iron oxide and barium titanate (1-x)BiFeO 3-xBaTiO3 (BFBT) with an emphasis on the room temperature piezoelectric properties and structural study. BFBT ceramics were prepared via the metal oxide solid-state preparation route. Addition of manganese oxide MnO2 increased the DC resistance by one to five orders of magnitude allowing high-field poling and piezoelectric strain measurements in Mn-modified BFBT ceramics. Piezoelectric d33 coefficients of 116 pC/N (low-field, Berlincourt) and 326 pC/N (effective, high-field) are reported for the compositions with x=0.25 and 0.33 respectively. Piezoelectric measurements using the Rayleigh law under applied large DC electric field indicated an increased low-field piezoelectric d33 coefficient to 150 pC/N (x=0.33). The DC bias is believed to stabilize the ferroclectric domain structure leading to stronger intrinsic and extrinsic contributions to the piezoelectric response in BFBT. Bright field TEM imaging confirmed formation of macroscopic domains following high field poling from initially frustrated domain state indicating the ability to induce long-range polarization order in BFBT ceramics. It is believed that the results of this work will contribute to the development of a family of lead-free piezoelectric materials based on BiFeO3-BaTiO3 system. KEYWORDS: Bismuth ferrite, Barium titanate, Lead-free, Piezoelectric ceramics, Crystal Structure

  15. Ceramic with zircon coating

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  16. Improvement of the dielectric breakdown strength and leakage currents of nano-sized CFO PZT particulate composite thin film with high particle loadings by controlled percolation for magnetoelectric applications

    NASA Astrophysics Data System (ADS)

    Muchenik Cena, Tomas Ignacio

    Magnetic and electric properties of a nano-sized particulate composite thin film consisting of non-percolating 11 nm superparamagnetic CoFe2O4 (CFO, Cobalt Ferrite) particles dispersed in a pure perovskite Pb[Zr 0.52Ti0.48]O3 (PZT, Lead Zirconate Titanate) matrix have been studied. The main objective of the study was to fabricate a composite with high particle loading conserving good dielectric breakdown strength (DBS) and leakage currents, which are commonly decreased at high loadings levels due to percolation. In this work, a composite with 38 vol% particulate loading showing no sign of percolation was prepared and characterized by DBS, leakage and polarization measurements. This improvement is explained with an analytical model proposed by Kusy, where percolation is increased when the diameter of the particulates is larger than the diameter of the matrix precursor. As a result of this, the leakage currents measurements, at 667 kV/cm, indicated an increase from 3*10--6 to 6 *10--5 A/cm2 ( 5 *10--10 and 9 *10--9 S/m ) for the samples with 1 and 38 vol% particulate loading, respectively, that remains lower than the leakage current of the PZT thin film, 6* 10--3A/cm2 (9 * 10--7 S/m), due to the reduction in crystallite size and grain orientation. No percolation was observed by the DBS characterization either, the increase of conductive CFO particles from 1 to 38 vol% decreased the DBS from 1800 kV/cm to 1200 kV/cm, respectively, which is still considerably higher than the DBS of the PZT thin film, 700 kV/cm, due to same reasons. Moreover, the behavior of the DBS for different particulate loadings is explained by an non-percolative analytical model consisting in the grain size effect and reduction of the effective film thickness given by the conductive phase, showing a good fit to the experimental data. This is in contrast to previously reported particulate composites, with magnetic and electric properties, that show percolation for low amounts of particulate loadings destroying the electric properties of the ferroelectric phase. The design proposed in this work is of great interest for the fabrication of films with high magnetic particulate loadings without degrading the electric properties for magnetoelectric applications.

  17. Optical and electro-optic properties of micrometric thick lead zirconate titanate films on (Pb{sub 0.86},La{sub 0.14})TiO{sub 3}/glass

    SciTech Connect

    Zhu, M. M.; Du, Z. H.; Ma, J.

    2009-07-15

    Highly (100)-oriented Pb(Zr{sub 0.52},Ti{sub 0.48})O{sub 3} (PZT) films of up to approx2.4 mum are deposited on the (Pb{sub 0.86},La{sub 0.14})TiO{sub 3} (PLT)-coated amorphous substrate by one cycle of sputtering and annealing. The films possess fibrous columnar nanostructures and vertically grow on the PLT/glass substrate. Microstructure analysis and property characterization indicate that the films possess very promising optical, waveguiding, and electro-optic (EO) properties, as well as low propagation loss. The transparency of >80% in the range of lambda=400-1200 nm and the linear EO coefficient of 341.4 pm/V have been measured in the films. Due to the large EO coefficient and the micrometric thickness, a giant phase retardation of 2.93 rad has been measured under an electric field of 50 kV/mm.

  18. Uniaxial Compression Experiments on Lead Zirconate Titanate 95/5-2Nb Ceramic: Evidence for an Orientation-Dependent, ''Maximum Compressive Stress'' Criterion for Onset of the Ferroelectric - Antiferroelectric Polymorphic Transformation

    SciTech Connect

    Zeuch, D.H.; Montgomery, S.T.; Holcomb, D.J.

    1999-07-26

    Some time ago we presented evidence that, under nonhydrostatic loading, the F{sub R1} {r_arrow} A{sub O} polymorphic transformation of unpoled PZT 95/5-2Nb (PNZT) ceramic began when the maximum compressive stress equaled the hydro-static pressure at which the transformation otherwise took place. Recently we showed that this simple criterion did not apply to nonhydrostatically compressed, poled ceramic. However, unpoled ceramic is isotropic, whereas poled ceramic has a preferred crystallographic orientation and is mechanically anisotropic. If we further assume that the transformation depends not only on the magnitude of the compressive stress, but also its orientation relative to some feature(s) of PNZT's crystallography, then these disparate results can be qualitatively resolved. It has long been known that this transformation can be triggered in uniaxial compression. Our modified hypothesis makes two predictions for transformation of unpoled polycrystals under uniaxial stress: (i) the transformation should begin when the maximum compressive stress, {sigma}{sub 1}, equals the hydrostatic pressure for transformation, and (ii) a steadily increasing axial stress should be required to drive the transformation.

  19. Polarization characterization of PZT disks and of embedded PZT plates by thermal wave methods

    SciTech Connect

    Eydam, Agnes Suchaneck, Gunnar Gerlach, Gerald; Esslinger, Sophia; Schönecker, Andreas; Neumeister, Peter

    2014-11-05

    In this work, the thermal wave method was applied to characterize PZT disks and embedded PZT plates with regard to the polarization magnitude and spatial homogeneity. The samples were exposed to periodic heating by means of a laser beam and the pyroelectric response was determined. Thermal relaxation times (single time constants or distributions of time constants) describe the heat losses of the PZT samples to the environment. The resulting pyroelectric current spectrum was fitted to the superposition of thermal relaxation processes. The pyroelectric coefficient gives insight in the polarization distribution. For PZT disks, the polarization distribution in the surface region showed a characteristic decrease towards the electrodes.

  20. Electrical properties of calcium modified PZT (52/48) ceramics

    NASA Astrophysics Data System (ADS)

    Kour, P.; Kumar, Pawan; Sinha, S. K.; Kar, Manoranjan

    2014-07-01

    To optimize the electrical properties of lead zirconate titanate, it was modified by calcium. Pb1-xCaxZr0.52Ti0.48O3, x=0.00, 0.02, 0.04, 0.06 and 0.10 composition, was prepared by the sol-gel technique. All the samples have been crystallized to a mixture of rhombohedral and tetragonal crystallographic phases. The dielectric constant increases with the increase in calcium concentration due to the increase in electronic polarization. The Curie temperature decreases with increase in calcium concentration of the sample. The ac conductivity of the sample obeys the Jonscher power law. The ac conductivity of the sample increases with the increase in calcium concentration. The impedance study shows the contribution from grain and grain boundary.

  1. Titan's Astrobiology

    NASA Astrophysics Data System (ADS)

    Raulin, F.; McKay, C.; Lunine, J.; Owen, T.

    This chapter describes the aspects of Saturn's moon Titan of astrobiological interest. Titan's prebiotic-like chemistry is reviewed, from the high atomosphere to the surface and subsurface, using the Cassini-Huygens data, with the help of theoretical modeling and experimental simulations. Similarities with and differences from the environment of the pre-biotic Earth are presented, and the lessons to be learned for Earth's organic chemical evolution on the prebiotic Earth discussed. The question of habitability and life on and in Titan is then considered, including the possibility of an exotic type of life that might exist in the liquid methane/ ethane lakes. Finally, the relation between Titan and the destiny of life on Earth is discussed.

  2. Titan Karst

    NASA Astrophysics Data System (ADS)

    Malaska, M. J.; Mitchell, K. L.; Hodyss, R.; Nerenberg, P. S.; Hayes, A. G.

    2015-10-01

    The morphological evidence, theoretical calculations, and laboratory simulation are all consistent with the concept that karst could be a viable explanation for the features and closed depressions observed on Titan.

  3. Characterizing Titan's Upper Atmosphere Using the Titan

    E-print Network

    Johnson, Robert E.

    Characterizing Titan's Upper Atmosphere Using the Titan Global Ionosphere-Thermosphere Model Jared the Thermosphere · We model the upper atmosphere from 500 km up to 1500 km. · Use the Titan Global Ionosphere, Titan (and now Jupiter and Saturn). ­ Details in Ridley et al. [2006], Bell et al. [2010a, 2010b

  4. Process 2.3 Sol-gel PZT

    E-print Network

    Healy, Kevin Edward

    -piezoelectric pyrochlore-phase PZT. 2.3 It is advisable to avoid high-temperature (>300 o C) processing post by piezoelectric PZT 4.6 Pyrochlore: the non-piezoelectric phase of PZT #12;C. Sherman & Y. Zhu 1/23/2015 5

  5. Modified lead titanate thin films for pyroelectric infrared detectors on gold electrodes

    NASA Astrophysics Data System (ADS)

    Ahmed, Moinuddin; Butler, Donald P.

    2015-07-01

    Pyroelectric infrared detectors provide the advantage of both a wide spectral response and dynamic range, which also has enabled systems to be developed with reduced size, weight and power consumption. This paper demonstrates the deposition of lead zirconium titanate (PZT) and lead calcium titanate (PCT) thin films for uncooled pyroelectric detectors with the utilization of gold electrodes. The modified lead titanate thin films were deposited by pulsed laser deposition on gold electrodes. The PZT and PCT thins films deposited and annealed at temperatures of 650 °C and 550 °C respectively demonstrated the best pyroelectric performance in this work. The thin films displayed a pyroelectric effect that increased with temperature. Poling of the thin films was carried out for a fixed time periods and fixed dc bias voltages at elevated temperature in order to increase the pyroelectric coefficient by establishing a spontaneous polarization of the thin films. Poling caused the pyroelectric current to increase one order of magnitude.

  6. Very High Frequency (Beyond 100 MHz) PZT Kerfless Linear Arrays

    PubMed Central

    Wu, Da-Wei; Zhou, Qifa; Geng, Xuecang; Liu, Chang-Geng; Djuth, Frank; Shung, K. Kirk

    2010-01-01

    This paper presents the design, fabrication, and measurements of very high frequency kerfless linear arrays prepared from PZT film and PZT bulk material. A 12-µm PZT thick film fabricated from PZT-5H powder/solution composite and a piece of 15-µm PZT-5H sheet were used to fabricate 32-element kerfless high-frequency linear arrays with photolithography. The PZT thick film was prepared by spin-coating of PZT sol-gel composite solution. The thin PZT-5H sheet sample was prepared by lapping a PZT-5H ceramic with a precision lapping machine. The measured results of the 2 arrays were compared. The PZT film array had a center frequency of 120 MHz, a bandwidth of 60% with a parylene matching layer, and an insertion loss of 41 dB. The PZT ceramic sheet array was found to have a center frequency of 128 MHz with a poorer bandwidth (40% with a parylene matching layer) but a better sensitivity (28 dB insertion loss). PMID:19942516

  7. Genetic Adaptive Control for PZT Actuators

    NASA Technical Reports Server (NTRS)

    Kim, Jeongwook; Stover, Shelley K.; Madisetti, Vijay K.

    1995-01-01

    A piezoelectric transducer (PZT) is capable of providing linear motion if controlled correctly and could provide a replacement for traditional heavy and large servo systems using motors. This paper focuses on a genetic model reference adaptive control technique (GMRAC) for a PZT which is moving a mirror where the goal is to keep the mirror velocity constant. Genetic Algorithms (GAs) are an integral part of the GMRAC technique acting as the search engine for an optimal PID controller. Two methods are suggested to control the actuator in this research. The first one is to change the PID parameters and the other is to add an additional reference input in the system. The simulation results of these two methods are compared. Simulated Annealing (SA) is also used to solve the problem. Simulation results of GAs and SA are compared after simulation. GAs show the best result according to the simulation results. The entire model is designed using the Mathworks' Simulink tool.

  8. Ti site occupancy in zircon

    NASA Astrophysics Data System (ADS)

    Tailby, N. D.; Walker, A. M.; Berry, A. J.; Hermann, J.; Evans, K. A.; Mavrogenes, J. A.; O'Neill, H. St. C.; Rodina, I. S.; Soldatov, A. V.; Rubatto, D.; Sutton, S. R.

    2011-02-01

    Ti site occupancy in zircon (ZrSiO 4) is fundamental to thermobarometry because substitution mechanisms control Ti content-temperature relations. Here we describe the results of three independent methods used to demonstrate that Ti substitutes for Si and not Zr in zircon. Zircon grains were synthesized from oxide powders held in a Na 2WO 4 flux at 1 bar and 1300 °C. Zircon grains equilibrated with rutile + cristobalite show Ti contents (1201 ppm) nearly half that of zircon grains equilibrated with srilankite ((Ti,Zr)O 2) + tetragonal zirconia (2640 ppm). The lower Ti content of zircon grains produced at silica-saturated conditions indicates that Ti substitution predominately occurs on the Si site. Moreover, the higher Ti contents of silica-saturated experiments at 1 bar (1201 ppm), relative to those at 1 GPa (457 ppm, Ferry and Watson, 2007), indicates a substantial pressure effect on Ti solubility in zircon. Measured Ti K-? edge X-ray Absorption Near Edge Structure (XANES) spectra of synthetic zircon grains show energies and normalized intensities akin to those seen among tetrahedrally coordinated Ti-bearing standard minerals, strongly suggesting that Ti occupies the Si site. Density functional theory (DFT) calculations confirm that Ti substitution is most likely to occur on the Si site and predict a Ti-O bond length of 1.797 Å (compared to an average of 2.160 Å for substitution on the Zr site), in excellent agreement with X-ray Absorption Fine Structure (EXAFS) spectra of experimentally grown zircon grains which indicate a value of 1.76(1) Å. The software FEFF 8.4 was used to simulate XANES spectra from the defect structures determined by DFT for Ti substituting on both the Si and Zr sites. The predicted spectrum for Ti on the Si site reproduces all the key features of the experimental zircon spectra, whereas Ti on the Zr site is markedly different. All applied methods confirm that Ti substitutes for Si in zircon. Consequently, the Ti content of zircon at a given pressure is not only a function of temperature, but will increase with decreasing silica activity. Because elements that activate or quench cathodoluminescence (CL) in zircon are incorporated into the Zr site, a decoupling of CL from Ti contents - incorporated on the Si site in zircon is expected. This hypothesis has been verified by a systematic CL-trace element study of natural and experimental zircon.

  9. Sensitivity of Micro Cantilever Mass Sensor Transduced by PZT Film

    NASA Astrophysics Data System (ADS)

    Lu, Jian; Ikehara, Tsuyoshi; Konno, Mitsuo; Maeda, Ryutaro; Mihara, Takashi

    Piezoelectric thin film transduced micro resonator offers competitive potential applications in mass sensing technology because of its low driving-voltage, self-actuation self-sensation capability and better impedance-matching with electronics. In this paper, the authors fabricated PZT cantilevers with different geometries and PZT thicknesses. Then the authors investigated the essential aspects of the PZT cantilever for mass-detection sensitivity from the viewpoint of mechanical quality factor of the cantilever and piezoelectric induced output of the PZT film. It was found that the mass-detection sensitivity of the cantilever was improved at thicker PZT film under atmospheric conditions by taking advantage of quality factor. The sensitivity can be further improved several times when pressure was reduced into the molecular flow region and the intrinsic region. For a given material properties and structural layer thickness, the cantilever with thicker PZT film was expected to exhibit high open circuit voltage output, while the cantilever with thinner PZT film was expected to show high piezoelectric charge output. In addition, the residual stress of PZT film was found decreased at thicker film. The effects of residual stress in PZT film on cantilever's sensitivity were therefore discussed in this paper.

  10. Etching fission tracks in zircons

    USGS Publications Warehouse

    Naeser, C.W.

    1969-01-01

    A new technique has been developed whereby fission tracks can be etched in zircon with a solution of sodium hydroxide at 220??C. Etching time varied between 15 minutes and 5 hours. Colored zircon required less etching time than the colorless varieties.

  11. Spectral Maps of Titan’s Surface

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin Ann; Penteado, Paulo; Turner, Jake D.; Khamsi, Tymon; Montiel, Nicholas J.

    2015-11-01

    Titan’s surface can be observed most clearly at 7 spectral regions that lie in between the strong methane bands in Titan’s spectrum. Within these ”windows”, between 0.8 to 5 microns, the surface is nonetheless obscured by methane and haze, the latter of which is optically thick at lower wavelengths. Studies of Titan’s surface must eliminate the effects of atmospheric extinction, which particularly at high latitudes, are not well constrained. A more general challenge in the study of planetary surfaces is the extraction of subtle spectral features from a large quantity of low-resolution data, which have dominant spectral trends, upon which lesser trends reside. This characteristic (a dominant spectral trend) is seen in Titan’s data: images at all 7 wavelengths appear essentially the same, with the bright terrain relatively bright at all wavelengths and vise versa. The question arises as to how to discern and map the smaller and orthogonal spectral trends of Titan’s surface in order to investigate the composition. Towards this goal we have constructed spectral maps of Titan’s surface by minimizing the covariance matrix of the I/F values (and separately the surface albedo) at the 7 window wavelengths. This application of the Principal Components Analyses (PCA) yields the orthogonal spectral trends based on the variance of the I/F values, and, separately, the surface albedos derived from radiative transfer models. Here we will present some of the interesting spectral trends detected through the application of this method to small sections of Titan’s surface.

  12. Zircons from kimberlite: New insights from oxygen isotopes, trace elements, and Ti in zircon thermometry

    E-print Network

    Meyers, Stephen R.

    Zircons from kimberlite: New insights from oxygen isotopes, trace elements, and Ti in zircon 2007; available online 21 May 2007 Abstract Zircons found in mantle-sourced kimberlite provide probes about the conditions of formation of these zircons. A suite of 88 zircons found in kimberlites from

  13. Crystallographic changes in lead zirconate titanate due to neutron irradiation

    DOE PAGESBeta

    Henriques, Alexandra; Graham, Joseph T.; Landsberger, Sheldon; Ihlefeld, Jon F.; Brennecka, Geoff L.; Brown, Donald W.; Forrester, Jennifer S.; Jones, Jacob L.

    2014-11-17

    Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method) is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure maymore »be investigated.« less

  14. Crystallographic changes in lead zirconate titanate due to neutron irradiation

    SciTech Connect

    Henriques, Alexandra; Graham, Joseph T.; Landsberger, Sheldon; Ihlefeld, Jon F.; Brennecka, Geoff L.; Brown, Donald W.; Forrester, Jennifer S.; Jones, Jacob L.

    2014-11-17

    Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method) is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure may be investigated.

  15. Zircon Recycling in Arc Intrusions

    NASA Astrophysics Data System (ADS)

    Miller, J.; Barth, A.; Matzel, J.; Wooden, J.; Burgess, S.

    2008-12-01

    Recycling of zircon has been well established in arc intrusions and arc volcanoes, but a better understanding of where and how zircons are recycled can help illuminate how arc magma systems are constructed. To that end, we are conducting age, trace element (including Ti-in-zircon temperatures; TzrnTi) and isotopic studies of zircons from the Late Cretaceous (95-85 Ma) Tuolumne Intrusive Suite (TIS) in the Sierra Nevada Batholith (CA). Within the TIS zircons inherited from ancient basement sources and/or distinctly older host rocks are uncommon, but recycled zircon antecrysts from earlier periods of TIS-related magmatism are common and conspicuous in the inner and two most voluminous units of the TIS, the Half Dome and Cathedral Peak Granodiorites. All TIS units have low bulk Zr ([Zr]<150 ppm) and thus low calculated zircon saturation temperatures (Tzrnsat). Within the Half Dome and Cathedral Peak, TzrnTi values are predominantly at or below average Tzrnsat, and there is no apparent correlation between age and TzrnTi. At temperatures appropriate for granodiorite/tonalite melt generation (at or above biotite dehydration; >825°C), [Zr] in the TIS is a factor of 2 to 3 lower than saturation values. Low [Zr] in TIS rocks might be attributed to a very limited supply of zircon in the source, by disequilibrium melting and rapid melt extraction [1], by melting reactions involving formation of other phases that can incorporate appreciable Zr [2], or by removal of zircon at an earlier stage of magma evolution. Based on a preliminary compilation of literature data, low [Zr] is common to Late Cretaceous N.A. Cordilleran granodioritic/tonalitic intrusions (typically <200 ppm and frequently 100-150 ppm for individual large intrusions or intrusive suites). We infer from this that [Zr] in anatectic melts is probably not limited by zircon supply and is primarily controlled by melting parameters. Comparison of the data from TIS with one of these intrusions, the smaller but otherwise similar Late Cretaceous Bear Lake Intrusive Suite (BLIS) in the San Bernardino Mountains (CA), is especially illuminating. Like the TIS the BLIS zircons also have low TzrnTi values (at or below Tzrnsat). However, unlike in the TIS, inherited zircons (or zircon cores) are common (BLIS is intruded into Paleoproterozoic basement). This comparison suggests that lack of abundant inherited or xenocrystic zircon in TIS rocks may be a function of whether they are in high abundance in the melt source or host rocks rather than strong initial undersaturation, and that low [Zr] might reflect melting at temperatures below biotite or amphibole dehydration. The high abundance of zircons with low TzrnTi could also reflect low anatectic temperatures as intermediate-felsic magmas that are initially undersaturated should be dominated by zircons with TzrnTi > Tzrnsat [3]. A corollary is that slightly older zircon antecrysts that are common in the inner units of the TIS could be considered inherited if they are derived from remelting of slightly older intrusions. Remelting at such low temperatures in the arc would require a source of external water. Refs: [1] Sawyer, J.Pet 32:701-738; [2] Fraser et al, Geology 25:607-610; [3] Harrison et al, Geology 35:635- 638

  16. Titanic: A Statistical Exploration.

    ERIC Educational Resources Information Center

    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. Chemically prepared PZT films doped with niobium

    SciTech Connect

    Tuttle, B.A.; Doughty, D.H.; Schwartz, R.; Garino, T.J.; Martinez, S.L.; Goodnow, D.; Hernandez, C.L.; Tissot, R.G.

    1989-01-01

    We report on the first ferroelectric measurements of chemically prepared thin films of PZT containing niobium, (PNZT). Polycrystalline, perovskite PNZT thin films were fabricated by spin coating Pt coated SiO{sub 2}/Si substrates with alkoxide solutions. We systematically doped our base composition, PZT 53/47, with niobium (0 to 10 at.%). Further compositional modifications included the variation of Zr/Ti ratio for films containing 2 at.% Nb. The dielectric constants measured for PNZT 2/56/44, 2/53/47 and 2/48/52 films were in good agreement with bulk values. Dielectric constants on the order of 700, 1000 and 500, respectively, were measured for these three films. Both linear and nonlinear current-voltage behavior was observed for our Pt/PNZT/Pt device structures, depending on the amplitude of the applied voltage and the temperature of measurement. We were able to make ferroelectric films of PNZT 2/53/47 (2 at.% Nb doping) with spontaneous polarizations of 0.2 C/m{sup 2} and coercive fields of 2.5 MV/m. PNZT films containing larger niobium additions (5 and 10 at.%) had inferior ferroelectric properties because of the presence of nonperovskite phases. 8 refs., 5 figs.

  18. Tides in Titan

    NASA Technical Reports Server (NTRS)

    Rappaport, Nicole J.

    1997-01-01

    Tides raised in Titan by Saturn give rise to a static and a periodic deformation; both will be measured with Doppler tracking during the CASSINI Tour of the Saturnian System. The latter deformation is due to the significant eccentricity of Titan's orbit and has a frequency equal to the orbital angular velocity of Titan.

  19. Titan Haze

    NASA Technical Reports Server (NTRS)

    Anderson, Carrie M.; West, Robert; Lavvas, Panayotis

    2011-01-01

    The Titan haze exerts a dominating influence on surface visibility and atmospheric radiative heating at optical and near-infrared wavelengths and our desire to understand surface composition and atmospheric dynamics provides a strong motivation to study the properties of the haze. Prior to the Cassini/Huygens missions the haze was known to be global in extent, with a hemispheric contrast asymmetry, with a complicated structure in the polar vortex region poleward of about 55 deg latitude, and with a distinct layer near 370 km altitude outside of the polar vortex at the time of the Voyager 2 flyby. The haze particles measured by the Pioneer and Voyager spacecraft were both highly polarizing and strongly forward scattering, a combination that seems to require an aggregation of small (several tens of nm radius) primary particles. These same properties were seen in the Cassini orbiter and Huygens Probe data. The most extensive set of optical measurements were made inside the atmosphere by the Descent Imager/Spectral Radiometer (DISR) instrument on the Huygens Probe. At the probe location as determined by the DISR measurements the average haze particle contained about 3000 primary particles whose radius is about 40 nm. Three distinct vertical regions were seen in the DISR data with differing particle properties. Refractive indices of the particles in the main haze layer resemble those reported by Khare et al. between O.3S and about 0.7 micron but are more absorbing than the Khare et al. results between 0.7 micron and the long-wavelength limit of the DISR spectra at 1.6 micron. These and other results are described by Tomasko et al., and a broader summary of results was given by Tomasko and West,. New data continue to stream in from the Cassini spacecraft. New data analyses and new laboratory and model results continue to move the field forward. Titan's 'detached' haze layer suffered a dramatic drop in altitude near equinox in 2009 with implications for the circulation and seasonal change in the stratosphere. The book chapter associated with this talk will also present new material on thermal-infrared data analysis and on new developments in laboratory work and haze microphysical modeling.

  20. Interior of Titan

    NASA Technical Reports Server (NTRS)

    Stevenson, David J.

    1992-01-01

    General principles of Titan formation and evolution are addressed. Attention is focused on the volatile reservoir (defined as all constituents more volatile than water) of Titan's interior. Volatile poor models, in which Titan is like Granymede or Callisto with a thin (observed) volatile veneer are discussed and discarded. Volatile rich models in which the present Titan consists of a methane clathrate shell overlying a deep water ammonia ocean and solid ammonia hydrate are discussed. Titan has a central core of rock which is about one half of the total mass, and a superficial hydrocarbon 'ocean' stored in subsurface caverns and pore space.

  1. Ferroelectric capped magnetization in multiferroic PZT/LSMO tunnel junctions

    SciTech Connect

    Kumar, Ashok Shukla, A. K.; Barrionuevo, D.; Ortega, N.; Katiyar, Ram S.; Shannigrahi, Santiranjan; Scott, J. F.

    2015-03-30

    Self-poled ultra-thin ferroelectric PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) (5 and 7?nm) films have been grown by pulsed laser deposition technique on ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) (30?nm) to check the effect of polar capping on magnetization for ferroelectric tunnel junction devices. PZT/LSMO heterostructures with thick polar PZT (7?nm) capping show nearly 100% enhancement in magnetization compared with thin polar PZT (5?nm) films, probably due to excess hole transfer from the ferroelectric to the ferromagnetic layers. Core-level x-ray photoelectron spectroscopy studies revealed the presence of larger Mn 3s exchange splitting and higher Mn{sup 3+}/Mn{sup 4+} ion ratio in the LSMO with 7?nm polar capping.

  2. Fabrication of Flexible Piezoelectric PZT/Fabric Composite

    PubMed Central

    Chen, Caifeng; Hong, Daiwei; Wang, Andong; Ni, Chaoying

    2013-01-01

    Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24?h, and reaction temperature 200°C. PMID:24348194

  3. Ferroelectric capped magnetization in multiferroic PZT/LSMO tunnel junctions

    NASA Astrophysics Data System (ADS)

    Kumar, Ashok; Barrionuevo, D.; Ortega, N.; Shukla, A. K.; Shannigrahi, Santiranjan; Scott, J. F.; Katiyar, Ram S.

    2015-03-01

    Self-poled ultra-thin ferroelectric PbZr0.52Ti0.48O3 (PZT) (5 and 7 nm) films have been grown by pulsed laser deposition technique on ferromagnetic La0.67Sr0.33MnO3 (LSMO) (30 nm) to check the effect of polar capping on magnetization for ferroelectric tunnel junction devices. PZT/LSMO heterostructures with thick polar PZT (7 nm) capping show nearly 100% enhancement in magnetization compared with thin polar PZT (5 nm) films, probably due to excess hole transfer from the ferroelectric to the ferromagnetic layers. Core-level x-ray photoelectron spectroscopy studies revealed the presence of larger Mn 3s exchange splitting and higher Mn3+/Mn4+ ion ratio in the LSMO with 7 nm polar capping.

  4. Tetragonal to rhombohedral transformation in the lead zirconium titanate lead magnesium niobate-lead titanate crystalline solution

    SciTech Connect

    Gupta, S.M.; Viehland, D.

    1998-01-01

    Evidence of a transformation from tetragonal to rhombohedral phases in a 80/20 mixture of lead ziconate titanate (PZT) (53/47) and lead magnesium niobate-lead titanate (PMN-PT) (65/35) was observed by x-ray diffraction, microstructural analysis, dielectric spectroscopy, and electrically-induced strain measurements. An increase in the electrically-induced strain and remanent polarization were found near 175{degree}C, which was significantly below the transition temperature (370{degree}C). Near this temperature, dielectric loss measurements revealed small changes, x-ray diffraction studies demonstrated a reduction in tetragonality, and hot-stage electron diffraction patterns revealed a change in spot splitting along the {l_angle}110{r_angle}. At room temperature, bright-field imaging revealed that normal size domains coexisted with polar nanodomains. These results are then compared to corresponding investigations of PZT and PMN-PT morphotropic phase boundary compositions. {copyright} {ital 1998 American Institute of Physics.}

  5. Titan Saturn System Mission

    NASA Technical Reports Server (NTRS)

    Reh, Kim R.

    2009-01-01

    Titan is a high priority for exploration, as recommended by NASA's 2006 Solar System Exploration (SSE) Roadmap. NASA's 2003 National Research Council (NRC) Decadal Survey and ESA's Cosmic Vision Program Themes. Recent revolutionary Cassini-Huygens discoveries have dramatically escalated interest in Titan as the next scientific target in the outer solar system. This study demonstrates that an exciting Titan Saturn System Mission (TSSM) that explores two worlds of intense astrobiological interest can be initiated now as a single NASA/ESA collaboration.

  6. Dielectric and ferroelectric analysis of nanoparticle/nanocrystalline barium titanate and PLZT.

    SciTech Connect

    DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William

    2010-07-01

    Attractive for numerous technological applications, ferroelectronic oxides constitute an important class of multifunctional compounds. Intense experimental efforts have been made recently in synthesizing, processing and understanding ferroelectric nanostructures. This work will present the systematic characterization and optimization of barium titanate and lead lanthanum zirconate titanate nanoparticle based ceramics. The nanoparticles have been synthesized using several solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric and ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

  7. Phosphorus chemistry on Titan

    NASA Astrophysics Data System (ADS)

    Pasek, Matthew A.; Mousis, Olivier; Lunine, Jonathan I.

    2011-04-01

    Phosphorus is a key element in biology and acts in many critical biochemical functions. The chemistry of phosphorus in the outer Solar System has not yet been quantified, hence the astrobiological relevance of phosphorus to possible life on places like Titan is unconstrained. We evaluate phosphorus chemistry on Titan using a combination of modeling and laboratory techniques. We show that phosphorus chemistry on Titan consists of exogenous phosphates and reduced oxidation state phosphorus compounds, and accretionary phosphine. Accretionary phosphorus is shown to be delivered primarily by rocks and ices in the saturnian sub-nebula, and heating during accretion concentrates phosphine in the crust of Titan. The exogenous compounds are capable of performing biologically-relevant chemistry, however they are active only in environments with substantial liquid water, either pure, or as a mixture with NH 3 or nitrile compounds. In contrast, we show that phosphine is soluble in methane and ethane on Titan's surface, hence phosphine likely participates in the hydrocarbon cycle on Titan. The lack of mobility of phosphate compounds on Titan's surface suggests that if life is present on Titan, it must have a fundamentally different biochemistry than does terrestrial life.

  8. Registration of ‘Titan’ Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Titan’ (Reg. no. CV- , PI ) virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea), developed and tested as VT 9506083-3 by the Virginia Agricultural Experiment Station, was released in May 2010. In Virginia, Titan was tested from 1997 to 2005 at several locations thr...

  9. Clash of the Titans

    ERIC Educational Resources Information Center

    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,"…

  10. Scaling laws In PZT/Si(001) Thin Films

    NASA Astrophysics Data System (ADS)

    Ramírez, Juan; Cortes, Alexander; Lopera, Wilson; Gómez, Maria Elena; Prieto, Pedro

    2006-03-01

    Self-affine scaling behavior of ferroelectric Pb(Zr1-xTix)O3 (PZT) thin films grown on Si(001) substrates has been investigated by AFM Atomic Force Microscope. PZT thin films were grown via Rf-sputtering technique at high oxygen pressures and at substrate temperatures 600 ^oC varying the deposition time and keeping all parameters. growth constant. The ?-global rough-exponent was founded close to 0.7 indicating a correlated growth. Anomalous scaling behavior was founded in all PZT/Si surfaces. A value of 0.5.for the ?-local value was founded. The local value of the roughness exponent is associated to the diffusional process on the first stage growth. Saturation roughness showed oscillation dependence with the PZT-thickness. This dependence can be explained by the mismatch between Si substrate and PZT thin film. These results are corroborated calculating the grain size for all samples. This work was supported by COLCIENCIAS under the Excellence Center for Novel Materials Contract no 0043-2005.

  11. Titan's Exotic Weather

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.

    2006-09-01

    Images of Titan, taken during the joint NASA and European Space Agency Cassini-Huygens mission, invoke a feeling of familiarity: washes wind downhill to damp lakebeds; massive cumuli form and quickly dissipate, suggestive of rain; and dark oval regions resemble lakes. These features arise from Titan's unique similarity with Earth: both cycle liquid between their surfaces and atmospheres, but in Titan's cool atmosphere it is methane that exists as a gas, liquid, and ice. While Titan enticingly resembles Earth, its atmosphere is 10 times thicker, so that its radiative time constant near the surface exceeds a Titan year, and prohibits large thermal gradients and seasonal surface temperature variations exceeding 3K. Titan also lacks oceans - central to Earth's climate - and instead stores much of its condensible in its atmosphere. As a result, Titan's weather differs remarkably from Earth's. Evidence for this difference appears in the location of Titan's large clouds, which frequent a narrow band at 40S latitude and a region within 30 latitude of the S. Pole. Ground-based and Cassini observations, combined with thermodynamic considerations, indicate that we are seeing large convective cloud systems. Detailed cloud models and general circulation models further suggest that these are severe rain storms, which will migrate with the change in season. Outside these migrating "gypsy" cloud bands, the atmosphere appears to be calm, humid and thus frequented by thin stratiform clouds. An intriguingly alien environment is predicted. Yet, the combined effects of Titan's patchy wet surface, atmospheric tides, possible ice volcanoes, and detailed seasonal variations remain unclear as we have witnessed only one season so far. This talk will review observations of Titan's lower atmosphere and modeling efforts to explain the observations, and explore the questions that still elude us.

  12. The evolution of the Titan rocket - Titan I to Titan II

    NASA Astrophysics Data System (ADS)

    Adams, Laurence J.

    1990-10-01

    The Titan I and Titan II rockets are described. The designs of the stages, test stands, and basing systems are considered, and the developmental history of each rocket is briefly recapitulated. The ways in which Titan II represents an evolution from Titan I are pointed out.

  13. Aerosol growth in Titan’s ionosphere

    PubMed Central

    Lavvas, Panayotis; Yelle, Roger V.; Koskinen, Tommi; Bazin, Axel; Vuitton, Véronique; Vigren, Erik; Galand, Marina; Wellbrock, Anne; Coates, Andrew J.; Wahlund, Jan-Erik; Crary, Frank J.; Snowden, Darci

    2013-01-01

    Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan’s upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere. PMID:23382231

  14. Optical characterization of ferroelectric PZT thin films by variable angle spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Shafiqur; Garcia, Carlos D.; Bhalla, Amar; Guo, Ruyan

    2014-09-01

    Ferroelectric thin films are used as high dielectric constant capacitors, infrared detectors, piezoelectric transducers, optical modulators, optical waveguides, and nonvolatile memory chips for dynamic random access memory (DRAM) etc. While ferroelectric and dielectric properties of these films have been extensively investigated, their optical properties have been comparatively less studied and of limited use in quantitative evaluation of multilayer thin films. In this work we explored the variable angle spectroscopic ellipsometry (VASE) technique for its effectiveness in physical property characterization. The VASE combined with its computer modeling tool enables nondestructive, nonintrusive, and contactless optical means for optical characterization. Crystalline Lead Zirconium Titanate PbZr0.52Ti0.48O3 (PZT) thin films, fabricated on SrTiO3 layer atop of Si substrates, were characterized using VASE (J.A. Woollam; Lincoln, NE, USA) by determining the ellipsometric parameters ? and ? as a function of wavelengths (200-1000 nm) and incident angles (65°, 70°,75°) at room temperature. A physical representation of the multilayer system was constructed by a six layer model (analysis software WVASE32, J.A. Woollam) through a step-by-step method. Other physical properties characterized by several well-known techniques on structure, morphology and topographical features correspond well with the models developed using VASE alone. The technique and the methodology developed have shown promises in identifying the respective thickness and optical properties of multilayer thin film system, with limited input of processing or composition information.

  15. Trace element chemistry of zircons from oceanic crust: A method for distinguishing detrital zircon provenance

    USGS Publications Warehouse

    Grimes, Craig B.; John, Barbara E.; Kelemen, P.B.; Mazdab, F.K.; Wooden, J.L.; Cheadle, Michael J.; Hanghoj, K.; Schwartz, J.J.

    2007-01-01

    We present newly acquired trace element compositions for more than 300 zircon grains in 36 gabbros formed at the slow-spreading Mid-Atlantic and Southwest Indian Ridges. Rare earth element patterns for zircon from modern oceanic crust completely overlap with those for zircon crystallized in continental granitoids. However, plots of U versus Yb and U/Yb versus Hf or Y discriminate zircons crystallized in oceanic crust from continental zircon, and provide a relatively robust method for distinguishing zircons from these environments. Approximately 80% of the modern ocean crust zircons are distinct from the field defined by more than 1700 continental zircons from Archean and Phanerozoic samples. These discrimination diagrams provide a new tool for fingerprinting ocean crust zircons derived from reservoirs like that of modern mid-ocean ridge basalt (MORB) in both modern and ancient detrital zircon populations. Hadean detrital zircons previously reported from the Acasta Gneiss, Canada, and the Narryer Gneiss terrane, Western Australia, plot in the continental granitoid field, supporting hypotheses that at least some Hadean detrital zircons crystallized in continental crust forming magmas and not from a reservoir like modern MORB. ?? 2007 The Geological Society of America.

  16. Metallic lead nanospheres discovered in ancient zircons

    PubMed Central

    Kusiak, Monika A.; Dunkley, Daniel J.; Wirth, Richard; Whitehouse, Martin J.; Wilde, Simon A.; Marquardt, Katharina

    2015-01-01

    Zircon (ZrSiO4) is the most commonly used geochronometer, preserving age and geochemical information through a wide range of geological processes. However, zircon U–Pb geochronology can be affected by redistribution of radiogenic Pb, which is incompatible in the crystal structure. This phenomenon is particularly common in zircon that has experienced ultra-high temperature metamorphism, where ion imaging has revealed submicrometer domains that are sufficiently heterogeneously distributed to severely perturb ages, in some cases yielding apparent Hadean (>4 Ga) ages from younger zircons. Documenting the composition and mineralogy of these Pb-enriched domains is essential for understanding the processes of Pb redistribution in zircon and its effects on geochronology. Using high-resolution scanning transmission electron microscopy, we show that Pb-rich domains previously identified in zircons from East Antarctic granulites are 5–30 nm nanospheres of metallic Pb. They are randomly distributed with respect to zircon crystallinity, and their association with a Ti- and Al-rich silica melt suggests that they represent melt inclusions generated during ultra-high temperature metamorphism. Metallic Pb is exceedingly rare in nature and previously has not been reported in association with high-grade metamorphism. Formation of these metallic nanospheres within annealed zircon effectively halts the loss of radiogenic Pb from zircon. Both the redistribution and phase separation of radiogenic Pb in this manner can compromise the precision and accuracy of U–Pb ages obtained by high spatial resolution methods. PMID:25848043

  17. Metallic lead nanospheres discovered in ancient zircons.

    PubMed

    Kusiak, Monika A; Dunkley, Daniel J; Wirth, Richard; Whitehouse, Martin J; Wilde, Simon A; Marquardt, Katharina

    2015-04-21

    Zircon (ZrSiO4) is the most commonly used geochronometer, preserving age and geochemical information through a wide range of geological processes. However, zircon U-Pb geochronology can be affected by redistribution of radiogenic Pb, which is incompatible in the crystal structure. This phenomenon is particularly common in zircon that has experienced ultra-high temperature metamorphism, where ion imaging has revealed submicrometer domains that are sufficiently heterogeneously distributed to severely perturb ages, in some cases yielding apparent Hadean (>4 Ga) ages from younger zircons. Documenting the composition and mineralogy of these Pb-enriched domains is essential for understanding the processes of Pb redistribution in zircon and its effects on geochronology. Using high-resolution scanning transmission electron microscopy, we show that Pb-rich domains previously identified in zircons from East Antarctic granulites are 5-30 nm nanospheres of metallic Pb. They are randomly distributed with respect to zircon crystallinity, and their association with a Ti- and Al-rich silica melt suggests that they represent melt inclusions generated during ultra-high temperature metamorphism. Metallic Pb is exceedingly rare in nature and previously has not been reported in association with high-grade metamorphism. Formation of these metallic nanospheres within annealed zircon effectively halts the loss of radiogenic Pb from zircon. Both the redistribution and phase separation of radiogenic Pb in this manner can compromise the precision and accuracy of U-Pb ages obtained by high spatial resolution methods. PMID:25848043

  18. Titan's organic chemistry

    NASA Technical Reports Server (NTRS)

    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.

  19. Functionalization of layered titanates.

    PubMed

    Ide, Yusuke; Sadakane, Masahiro; Sano, Tsuneji; Ogawa, Makoto

    2014-03-01

    This review article describes the synthesis, modification, and function of lepidocrocite-type layered titanate (A(x)Ti(2-y)M(y)O4, A: A, interlayer cation; M, metal or vacancy). Due to the compositional variation, which affects cation exchange, semiconducting and swelling properties, lepidocrocite-type layered titanates have attracted increasing attention in solid-state materials chemistry. The immobilization of functional units has been done to improve the properties as well as to impart additional functions. Here, we highlight recent developments of hybrid materials derived from the intercalation of inorganic and organic cations, organic functional groups, and nanoparticles into lepidocrocite-type layered titanates. PMID:24745207

  20. Titan's thick haze layer

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Titan's thick haze layer is shown in this enhanced Voyager 1 image taken Nov. 12, 1980 at a distance of 435,000 kilometers (270,000 miles). Voyager images of Saturn's largest moon show Titan completely enveloped by haze that merges with a darker 'hood' or cloud layer over the north pole. Such a mantle is not present at the south pole. At Voyager's closest approach to Titan on Nov. 11, 1980, spacecraft instruments found that the moon has a substantial atmosphere, far denser than that of Mars and possibly denser than Earth's. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  1. A linearity tunable DBR fiber laser based on closed-loop PZT

    NASA Astrophysics Data System (ADS)

    Li, Guoyu; Li, Yan; Yang, Kang; Liu, Mingsheng

    2013-02-01

    A linearity tunable fiber laser based on closed-loop piezoelectric ceramics (PZT) is proposed and successfully demonstrated. The cavity of the distributed Bragg reflector (DBR) fiber laser is fixed on the PZT, and the displacement sensor attached on the PZT is monitoring and compensating the nonlinear hysteresis of the PZT real-timely. Experimental results show that the tuning curve of the DBR fiber laser is linear with the tuning range nearly 0.8 nm. Furthermore, the automatic tuning DBR fiber laser driven by the sawtooth wave is realized in closed-loop PZT operation.

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

    SciTech Connect

    Not Available

    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. Modeling and identification of nonlinear electroelastic and dissipative parameters for PZT-5A and PZT-5H bimorphs: a dynamical systems approach

    NASA Astrophysics Data System (ADS)

    Leadenham, Stephen; Ferri, Brian; Erturk, Alper

    2015-04-01

    Electroelastic and dissipative nonlinearities of commonly used soft piezoelectrics (PZT-5A and PZT-5H) are pronounced in various engineering applications such as actuation, sensing, vibration control, and most recently, in energy harvesting from dynamical systems. The present work investigates the nonlinear nonconservative dynamic behavior of bimorph piezoelectric cantilevers under low-to-high excitation levels with a focus on most popular soft piezoceramics: PZT-5A and PZT-5H. A unified mathematical framework we recently developed is analyzed by using the method of harmonic balance to identify and validate nonlinear system parameters based on a set of rigorous experiments for different samples.

  4. Titan Photochemistry 1974- 2014

    NASA Astrophysics Data System (ADS)

    Strobel, D. F.

    2014-04-01

    It has been 40 years since I published the first paper on Titan photochemistry (Strobel, Icarus, 21, 466- 470, 1974) and pointed out the fundamental difference between the giant planets and Titan. Namely, that unlike the giant planets, light constituents, principally H and H2, can readily escape from the atmosphere of Titan leading to irreversible loss of CH4 from photolysis and a requirement for replenishment by outgassing to maintain a stable presence in the atmosphere on timescales exceeding 50 MY. Since then we have had the Voyager Mission and now the on-going Cassini Huygens Mission plus ground-based telescope observations all contributing to our knowledge about the fascinating photochemical processes on Titan. The talk will finish with an analysis of where we are in our understanding and the outstanding issues that still need to be resolved.

  5. Titan's Lower Atmosphere

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin Ann

    2007-09-01

    Saturn's largest moon, Titan, sports an atmosphere 10 times thicker than Earth's. Like Earth, the moon's atmosphere is N2 based and possesses a rich organic chemistry. In addition, similar to the terrestrial hydrological cycle, Titan has a methane cycle, with methane clouds, rain and seas. Presently, there is a revolution in our understanding of the moon, as data flows in and is analyzed from the NASA and ESA Cassini-Huygens mission. For example, seas were detected only this year. Here I will discuss the evolution of our understanding of Titan's atmosphere, its composition, chemistry, dynamics and origin. Current open questions will also be presented. Studies of Titan's atmosphere began and evolved to the present state in less time than that of a single scientist's career. This short interlude of activity demonstrates the rigors of the scientific method, and raises enticing questions about the workings and evolution of an atmosphere.

  6. Titan Casts Revealing Shadow

    NASA Astrophysics Data System (ADS)

    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 diameter, which corresponds to the size of a dime as viewed from about two and a half miles. Illustration of Crab, Titan's Shadow and Chandra Illustration of Crab, Titan's Shadow and Chandra Unlike almost all of Chandra's images which are made by focusing X-ray emission from cosmic sources, Titan's X-ray shadow image was produced in a manner similar to a medical X-ray. That is, an X-ray source (the Crab Nebula) is used to make a shadow image (Titan and its atmosphere) that is recorded on film (Chandra's ACIS detector). Titan's atmosphere, which is about 95% nitrogen and 5% methane, has a pressure near the surface that is one and a half times the Earth's sea level pressure. Voyager I spacecraft measured the structure of Titan's atmosphere at heights below about 300 miles (500 kilometers), and above 600 miles (1000 kilometers). Until the Chandra observations, however, no measurements existed at heights in the range between 300 and 600 miles. Understanding the extent of Titan's atmosphere is important for the planners of the Cassini-Huygens mission. The Cassini-Huygens spacecraft will reach Saturn in July of this year to begin a four-year tour of Saturn, its rings and its moons. The tour will include close flybys of Titan that will take Cassini as close as 600 miles, and the launching of the Huygens probe that will land on Titan's surface. Chandra's X-ray Shadow of Titan Chandra's X-ray Shadow of Titan "If Titan's atmosphere has really expanded, the trajectory may have to be changed." said Tsunemi. The paper on these results has been accepted and is expected to appear in a June 2004 issue of The Astrophysical Journal. Other members of the research team were Haroyoski Katayama (Osaka University), David Burrows and Gordon Garmine (Penn State University), and Albert Metzger (JPL). Chandra observed Titan from 9:04 to 18:46 UT on January 5, 2003, using its Advanced CCD Imaging Spectrometer instrument. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters,

  7. Raising the Titanic.

    ERIC Educational Resources Information Center

    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)

  8. ORNL debuts Titan supercomputer

    E-print Network

    detail," said James Hack, director of ORNL's National Center for Computational Sciences. "The work through the process for final system acceptance. The lion's share of access to Titan in the coming. . . . . . . . . . . . .2 Service anniversaries . . . . . .3 Benefits. . . . . . . . . . . . . . . . . .4 Tennessee Science

  9. Titan's Ammonia Feature

    NASA Technical Reports Server (NTRS)

    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.

  10. Barium titanate nanocomposite capacitor FY09 year end report.

    SciTech Connect

    Stevens, Tyler E.; DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William; Fellows, Benjamin D.

    2009-11-01

    This late start RTBF project started the development of barium titanate (BTO)/glass nanocomposite capacitors for future and emerging energy storage applications. The long term goal of this work is to decrease the size, weight, and cost of ceramic capacitors while increasing their reliability. Ceramic-based nanocomposites have the potential to yield materials with enhanced permittivity, breakdown strength (BDS), and reduced strain, which can increase the energy density of capacitors and increase their shot life. Composites of BTO in glass will limit grain growth during device fabrication (preserving nanoparticle grain size and enhanced properties), resulting in devices with improved density, permittivity, BDS, and shot life. BTO will eliminate the issues associated with Pb toxicity and volatility as well as the variation in energy storage vs. temperature of PZT based devices. During the last six months of FY09 this work focused on developing syntheses for BTO nanoparticles and firing profiles for sintering BTO/glass composite capacitors.

  11. ALMA observations of Titan

    NASA Astrophysics Data System (ADS)

    Moreno, Raphael; Lellouch, Emmanuel; Vinatier, Sandrine; Gurwell, Mark A.; Lara, Luisa M.; Moullet, Arielle; Hidayat, Taufiq

    2014-11-01

    We report submm observations of Titan performed with the ALMA interferometer from our cycle 0 data, centered around the rotational frequencies of HCN(4-3) and HNC(4-3), i.e. 354 and 362 GHz. The most extended configuration of the array in cycle 0 yielded disk-resolved emission spectra of Titan with an angular resolution of 0.54x0.42 arcsec. Titan’s angular surface diameter was 0.77 arcsec. Data were acquired in June-August 2012 near the greatest eastern and western elongations of Titan at a spectral resolution of 122 kHz (?/d ? = 3.10^6).We have obtained maps of several nitriles present in Titan’ stratosphere: HCN, HC3N, CH3CN, HNC, DCN, and obtain the detection of the isotopes CH3C13N and HCCC15N as well as line spectroscopic detection of C2H5CN.This is a work in progress, maps of nitriles will be presented

  12. Spectral Characteristics of Titan's Surface

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.; Turner, Jake D.; Penteado, Paulo; Khamsi, Tymon B.; Soderblom, Jason M.

    2014-11-01

    Cassini/Huygens and ground-based measurements of Titan reveal an eroded surface, with lakes, dunes, and sinuous washes. These features, coupled with measurements of clouds and rain, indicate the transfer of methane between Titan’s surface and atmosphere. The presence of methane-damp lowlands suggests further that the atmospheric methane (which is continually depleted through photolysis) may be supplied by sub-surface reservoirs. The byproducts of methane photolysis condense onto the surface, leaving layers of organic sediments that record Titan’s past atmospheres.Thus knowledge of the source and history of Titan's atmosphere requires measurements of the large scale compositional makeup of Titan's surface, which is shrouded by a thick and hazy atmosphere. Towards this goal, we analyzed roughly 100,000 spectra recorded by Cassini’s Visual and Infrared Mapping Spectrometer (VIMS). Our study is confined to the latitude region (20S—20N) surrounding the landing site of the Huygens probe (at 10S, 192W), which supplied only measurement of the vertical profiles of the methane abundance and haze scattering characteristics. VIMS near-IR spectral images indicate subtle latitudinal and temporal variations in the haze characteristics in the tropics. We constrain these small changes with full radiative transfer analyses of each of the thousands of VIMS spectra, which were recorded of different terrains and at different lighting conditions. The resulting models of Titan’s atmosphere as a function of latitude and year indicate the seasonal migration of Titan’s tropical haze and enable the derivation of Titan’s surface albedo at 8 near-IR wavelength regions where Titan’s atmosphere is transparent enough to allow visibility to the surface. The resultant maps of Titan’s surface indicate a number of terrain types with distinct spectral characteristics that are suggestive of atmospheric and surficial processes, including the deposition of organic material, erosion of sediments and potential sources of methane.

  13. Dating metamorphism using zircons in metabasic rocks

    NASA Astrophysics Data System (ADS)

    Connelly, J. N.; McFarlane, C. R. M.

    2003-04-01

    Regional metamorphism typically occurs over time spans that exceed errors for U-Pb ages of zircon by an order of magnitude or more. As we attempt to refine our understanding of metamorphic excursions of rocks during tectonic events, our understanding of the reactions and processes that control isotopically derived ages become more critical. However, a range of variables affecting the formation and modification of these chronometric phases (rock and fluid compositions, cooling rates and specific PT geometries) complicate rigorous integration of geochronometric, petrogenetic, and geothermobarometric data to define meaningful PTt paths. Dating major metamorphic phases (GRT, CPX, PL, etc) offers the most direct link to the timing of specific mineral paragenesis or equilibria, but invalid assumptions regarding closure and initial equilibrium may yield misleading or spurious ages. Refining the use of conventionally employed minor chronometric phases will require a better understanding of their paragenetic relationship with major phases that are typically used to define PT conditions. Towards this end, metabasites may offer an under-utilized means to constrain the timing of reactions given: 1) their relatively simple major mineral paragenesis, 2) that primary zircon is nearly always absent, 3) the common occurrence of low-U metamorphic zircon, and 4) the robustness of these zircons through subsequent thermal events. Additionally, but not restricted to metabasites, high Pb-retention temperature(s) of pristine zircon ensures determining a reaction (rather than closure) age. To evaluate the utility of zircons in metabasites to define “metamorphic ages”, we present U-Pb zircon data from a range of geological settings. Of particular interest, metabasites from single outcrops may return independently robust but distinctly different ages. From this we infer that zircons form from different reactions at different times along the PT path, controlled by bulk composition and/or P(fluids). Furthermore, these ages are distinctly older than ages derived from Sm-Nd (GRT-TTN-CPX-AP) isochrons. We presume that zircon formation is linked to, and therefore dates, the first breakdown of pyroxene to lower temperature, hydrous phases, a reaction that liberates SiO2 and Zr. Formation of granulites directly from rocks with primary pyroxene may, therefore, preclude the formation of zircon during metamorphism. But once formed, zircon appears stable and isotopically robust through subsequent metamorphism. It is, therefore, not assured that zircons in metabasites will faithfully record all high temperature events. However, the potential to link zircon formation in metabasites directly to major phase reactions offers exciting prospects to examine metamorphic diachroneity across regionally metamorphosed terrains, date metamorphic reactions, and construct meaningful PTt paths.

  14. ALMA observations of Titan

    NASA Astrophysics Data System (ADS)

    Moreno, R.; Lellouch, E.; Vinatier, S.; Gurwell, M.; Moullet, A.; Lara, L. M.; Hidayat, T.

    2014-04-01

    We report submm observations of Titan performed with the ALMA interferometer centered at the rotational frequencies of HCN(4-3) and HNC(4-3), i.e. 354 and 362 GHz. The most extended configuration of the array in cycle 0 yielded diskresolved emission spectra of Titan with an angular resolution of 0.54x0.42 arcsec. Titan's angular surface diameter was 0.77 arcsec. Data were acquired in June-August 2012 near the greatest eastern and western elongations of Titan at a spectral resolution of 122 kHz (?/d ? = 3106). We have obtained maps of several nitriles present in Titan' stratosphere: HCN, HC3N, CH3CN, HNC and other weak lines (isotopes, vibrationally excited lines, …). A detailed study of the relative line intensities and FWHM is ongoing. With the combination of all these detected rotational lines, we expect to constrain the spatial and vertical distribution of these species and to derive the HNC/HCN ratio as well as isotopic ratios. Moreover, Doppler lineshift measurements will enable us to constrain the zonal wind flow in the upper atmosphere. This analysis will be presented, as well as a comparison with vertical profiles expected from photochemical models.

  15. Zircon dating of oceanic crustal accretion.

    PubMed

    Lissenberg, C Johan; Rioux, Matthew; Shimizu, Nobumichi; Bowring, Samuel A; Mével, Catherine

    2009-02-20

    Most of Earth's present-day crust formed at mid-ocean ridges. High-precision uranium-lead dating of zircons in gabbros from the Vema Fracture Zone on the Mid-Atlantic Ridge reveals that the crust there grew in a highly regular pattern characterized by shallow melt delivery. Combined with results from previous dating studies, this finding suggests that two distinct modes of crustal accretion occur along slow-spreading ridges. Individual samples record a zircon date range of 90,000 to 235,000 years, which is interpreted to reflect the time scale of zircon crystallization in oceanic plutonic rocks. PMID:19179492

  16. Flying by Titan

    NASA Technical Reports Server (NTRS)

    Pelletier, Frederic J.; Antreasian, Peter G.; Ardalan, Shadan M.; Criddle, Kevin E.; Ionasescu, Rodica; Jacobson, Robert A.; Jones, Jeremy B.; Parcher, Daniel W.; Roth, Duane C.; Thompson, Paul F.; Vaughan, Andrew T.

    2008-01-01

    The Cassini spacecraft encounters the massive Titan about once every month. These encounters are essential to the mission as Titan is the only satellite of Saturn that can provide enough gravity assist to shape the orbit tour and allow outstanding science for many years. From a navigation point of view, these encounters provide many challenges, in particular those that fly close enough to the surface for the atmospheric drag to perturb the orbit. This paper discusses the dynamics models developed to successfully navigate Cassini and determine its trajectory. This includes the moon's gravity pull with its second degree zonal harmonics J2, the attitude thrust control perturbations and the acceleration of drag.

  17. Titan's Winter Polar Vortex

    NASA Technical Reports Server (NTRS)

    Flasar, F.M.; Achterberg, R.K.; Schinder, P.J.

    2008-01-01

    Titan's atmosphere has provided an interesting study in contrasts and similarities with Earth's. While both have N$_2$ as the dominant constituent and comparable surface pressures $\\sim1$ bar, Titan's next most abundant molecule is CH$_4$, not O$_2$, and the dissociative breakup of CH$_4$ and N$_2$ by sunlight and electron impact leads to a suite of hydrocarbons and nitriles, and ultimately the photochemical smog that enshrouds the moon. In addition, with a 15.95-day period, Titan is a slow rotator compared to Earth. While the mean zonal terrestrial winds are geostrophic, Titan's are mostly cyclostrophic, whipping around the moon in as little as 1 day. Despite the different dynamical regime, Titan's winter stratosphere exhibits several characteristics that should be familiar to terrestrial meteorologists. The cold winter pole near the 1 -mbar level is circumscribed by strong winds (up to 190 m/s) that act as a barrier to mixing with airmasses at lower latitudes. There is evidence of enhancement of several organic species over the winter pole, indicating subsidence. The adiabatic heating associated with this subsidence gives rise to a warm anomaly at the 0.01-mbar level, raising the stratopause two scale heights above its location at equatorial latitudes. Condensate ices have been detected in Titan's lower stratosphere within the winter polar vortex from infrared spectra. Although not always unambiguously identified, their spatial distribution exhibits a sharp gradient, decreasing precipitously across the vortex away from the winter pole. The interesting question of whether there is important heterogeneous chemistry occurring within the polar vortex, analogous to that occurring in the terrestrial polar stratospheric clouds in the ozone holes, has not been addressed. The breakup of Titan's winter polar vortex has not yet been observed. On Earth, the polar vortex is nonlinearly disrupted by interaction with large-amplitude planetary waves. Large-scale waves have not been identified in Titan's atmosphere, so the decay of its polar vortex may be more gradual than on Earth. Observations from an extended Cassini mission into late northern spring should provide critical data indicating whether the vortex goes away with a bang or just fades away.

  18. Geometry adaptive control of a composite reflector using PZT actuator

    NASA Astrophysics Data System (ADS)

    Lan, Lan; Jiang, Shuidong; Zhou, Yang; Fang, Houfei; Tan, Shujun; Wu, Zhigang

    2015-04-01

    Maintaining geometrical high precision for a graphite fiber reinforced composite (GFRC) reflector is a challenging task. Although great efforts have been placed to improve the fabrication precision, geometry adaptive control for a reflector is becoming more and more necessary. This paper studied geometry adaptive control for a GFRC reflector with piezoelectric ceramic transducer (PZT) actuators assembled on the ribs. In order to model the piezoelectric effect in finite element analysis (FEA), a thermal analogy was used in which the temperature was applied to simulate the actuation voltage, and the piezoelectric constant was mimicked by a Coefficient of Thermal Expansion (CTE). PZT actuator's equivalent model was validated by an experiment. The deformations of a triangular GFRC specimen with three PZT actuators were also measured experimentally and compared with that of simulation. This study developed a multidisciplinary analytical model, which includes the composite structure, thermal, thermal deformation and control system, to perform an optimization analysis and design for the adaptive GFRC reflector by considering the free vibration, gravity deformation and geometry controllability.

  19. Refractory Materials of Zirconate. Part 2: Synthesis and some properties of strontium, zirconate, calcium zirconate and barium zirconate

    NASA Technical Reports Server (NTRS)

    Okubo, Tsutomo; Yonemochi, Osamu; Nakamura, Kazuo; Maeda, Minoru

    1988-01-01

    Chemical compounds SrZrO3, CaZrO3, and BaZrO3 were synthesized by solid reaction and arc fusion, and their properties examined. Results were as follows: (1) in the synthesis of CaZrO3 by solid reaction, ZrO2 solid solution with cubic form was produced, which then changed into CaZrO3; (2) the BaZrO3 was a cubic form and did not show any transformation, while SrZrO3 and CaZrO3 with an orthorhombic form transformed to a cubic form at high temperature; and (3) the solubility of BaZrO3 in acid and its vaporization rate at a high temperature were greater than those of zirconates.

  20. Zirconate pyrochlores under high pressure

    SciTech Connect

    Xiao, Haiyan; Zhang, Fuxiang; Gao, Fei; Ewing, Rodney C.; Weber, William J

    2010-01-01

    Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicate that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

  1. Zirconate pyrochlores under high pressure

    SciTech Connect

    Xiao, Haiyan Y.; Zhang, F. X.; Gao, Fei; Lang, Maik; Ewing, Rodney C.; Weber, William J.

    2010-07-12

    Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicates that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

  2. Solution Synthesis and Processing of PZT Materials for Neutron Generator Applications

    SciTech Connect

    Anderson, M.A.; Ewsuk, K.G.; Montoya, T.V.; Moore, R.H.; Sipola, D.L.; Tuttle, B.A.; Voigt, J.A.

    1998-12-01

    A new solution synthesis route has been developed for the preparation of lead-based ferroelectric materials (patent filed). The process produces controlled stoichiometry precursor powders by non-aqueous precipitation. For a given ferroelectric material to be prepared, a metal acetate/alkoxide solution containing constituent metal species in the appropriate ratio is mixed with an oxalic acid/n-propanol precipitant solution. An oxalate coprecipitate is instantly fonned upon mixing that quantitatively removes the metals from solution. Most of the process development was focused on the synthesis and processing of niobium-substituted lead zirconate titanate with a Zr-to-Ti ratio of 95:5 (PNZT 95/5) that has an application in neutron generator power supplies. The process was scaled to produce 1.6 kg of the PNZT 95/5 powder using either a sen-ii-batch or a continuous precipitation scheme. Several of the PNZT 95/5 powder lots were processed into ceramic slug form. The slugs in turn were processed into components and characterized. The physical properties and electrical performance (including explosive functional testing of the components met the requirements set for the neutron generator application. Also, it has been demonstrated that the process is highly reproducible with respect to the properties of the powders it produces and the properties of the ceramics prepared from its powders. The work described in this report was funded by Sandia's Laboratory Directed Research and Development Program.

  3. Isotopic Composition of Oxygen in Lunar Zircons

    NASA Technical Reports Server (NTRS)

    Nemchin, A. A.; Whitehouse, M. J.; Pidgeon, R. T.; Meyer, C.

    2005-01-01

    The recent discovery of heavy oxygen in zircons from the Jack Hills conglomerates Wilde et al. and Mojzsis et al. was interpreted as an indication of presence of liquid water on the surface of Early Earth. The distribution of ages of Jack Hills zircons and lunar zircons appears to be very similar and therefore analysis of oxygen in the lunar grains may provide a reference frame for further study of the early history of the Earth as well as give additional information regarding processes that operated on the Moon. In the present study we have analysed the oxygen isotopic composition of zircon grains from three lunar samples using the Swedish Museum of Natural History CAMECA 1270 ion microprobe. The samples were selected as likely tests for variations in lunar oxygen isotopic composition. Additional information is included in the original extended abstract.

  4. Sputtered highly oriented PZT thin films for MEMS applications

    NASA Astrophysics Data System (ADS)

    Kalpat, Sriram S.

    Recently there has been an explosion of interest in the field of micro-electro-mechanical systems (MEMS). MEMS device technology has become critical in the growth of various fields like medical, automotive, chemical, and space technology. Among the many applications of ferroelectric thin films in MEMS devices, microfluidics is a field that has drawn considerable amount of research from bio-technology industries as well as chemical and semiconductor manufacturing industries. PZT thin films have been identified as best suited materials for micro-actuators and micro-sensors used in MEMS devices. A promising application for piezoelectric thin film based MEMS devices is disposable drug delivery systems that are capable of sensing biological parameters, mixing and delivering minute and precise amounts of drugs using micro-pumps or micro mixers. These devices call for low driving voltages, so that they can be battery operated. Improving the performance of the actuator material is critical in achieving battery operated disposal drug delivery systems. The device geometry and power consumption in MEMS devices largely depends upon the piezoelectric constant of the films, since they are most commonly used to convert electrical energy into a mechanical response of a membrane or cantilever and vice versa. Phenomenological calculation on the crystal orientation dependence of piezoelectric coefficients for PZT single crystal have reported a significant enhancement of the piezoelectric d33 constant by more than 3 times along [001] in the rhombohedral phase as compared to the conventionally used orientation PZT(111) since [111] is the along the spontaneous polarization direction. This could mean considerable improvement in the MEMS device performance and help drive the operating voltages lower. The motivation of this study is to investigate the crystal orientation dependence of both dielectric and piezoelectric coefficients of PZT thin films in order to select the appropriate orientation that could improve the MEMS device performance. Potential application of these devices is as battery operated disposable drug delivery systems. This work will also investigate the fabrication of a flexural plate wave based microfluidic device using the PZT thin film of appropriate orientation that would enhance the device performance. (Abstract shortened by UMI.)

  5. Detrital Zircon Geochronology Applied to Basin Analysis

    NASA Astrophysics Data System (ADS)

    Gehrels, G. E.

    2014-12-01

    During the past ~15 years, detrital zircon geochronology has developed into a powerful tool for analyzing sedimentary features and processes. One of the most common applications is to use the ages of the youngest detrital zircons in a sample to constrain the maximum age of deposition. In an ideal case, for example in a region with active volcanism, the youngest zircon grains would have crystallized immediately prior to deposition and the lag time between crystallization and deposition is negligible. Such ages provide opportunities for reconstructing the chrono-stratigraphy of a sedimentary sequence, and establishing the chrono-correlation of sedimentary units and surfaces across broad regions. Most sedimentary units also yield detrital zircon grains that significantly predate deposition (because of the extreme durability of zircon). The ages of these grains provide a fingerprint (or chrono-facies) that can be used for comparison of sedimentary units. Such comparisons have traditionally been based on the presence/absence of age populations, but with larger data sets it is becoming possible to determine proportions of ages in a robust fashion, and thereby compare strata much more quantitatively. Common methodology for conducting these types of analyses is to determine ages for several hundred detrital zircon grains from each sample, with random selection of grains to generate a robust age distribution. If necessary, additional analyses are conducted on "young-looking" grains to improve precision on the max depo age. Such analyses commonly yield max depo ages that are reliable to 1-2%. Determining whether a max depo age approximates true depo age commonly requires geologic arguments (e.g., presence of volcanic lithic fragments, size/shape of the youngest zircon crystals, order of youngest ages in a sedimentary sequence). In addition to these chronologic applications, detrital zircon ages provide powerful tools for determining provenance, reconstructing dispersal pathways (commonly involving episodes of recycling), characterizing source regions, establishing connections between drainage areas and offshore basins, and evaluating reservoir characteristics.

  6. Propane on Titan

    E-print Network

    H. G. Roe; T. K. Greathouse; M. J. Richter; J. H. Lacy

    2003-09-23

    We present the first observations of propane (C$_3$H$_8$) on Titan that unambiguously resolve propane features from other numerous stratospheric emissions. This is accomplished using a $R=\\lambda/\\delta\\lambda\\approx10^5$ spectrometer (TEXES) to observe propane's $\

  7. The lakes of Titan

    USGS Publications Warehouse

    Stofan, E.R.; Elachi, C.; Lunine, J.I.; Lorenz, R.D.; Stiles, B.; Mitchell, K.L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.

    2007-01-01

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70?? north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table. ??2007 Nature Publishing Group.

  8. Future Titan Mission Studies

    NASA Astrophysics Data System (ADS)

    Kakuda, R.; Spilker, T.; Baines, K.; Lorenz, R.

    Exploration of Titan will remain a solar system science priority even (or especially) after Cassini. Not only does Titan offer an array of meteorological, oceanographical and geological phenomena richer than anywhere except Earth, but Titan's importance as an astrobiological target with a rich organic inventory has been long recognized. In-situ surface chemistry studies, meteorological and seismological monitoring and high-resolution geomorphological investigations are beyond Cassini's capabilities. Concepts for future missions involve a mobile airborne platform able to access sur- face materials at a number of locations, and an orbiter for communications support and survey observations. Detailed studies at JPL have evaluated mission options in- cluding a lander or a blimp (airship) supported by an orbiter, with launch in the 2010- 2015 timeframe, allowing early Cassini results to refine the mission science goals and implementation strategies. After a 10 year cruise and aerocapture, the mission would provide an enormous bounty of data from a 1-3 year tour of Titan. International col- laboration would broaden the scope of the mission and would build on the successful Cassini-Huygens experience.

  9. Sinking with the Titanic

    NASA Astrophysics Data System (ADS)

    Bagnoli, Franco

    2015-03-01

    In the Titanic movie, when the rear part of the ship is about to sink, Jack Dawson (Leonardo DiCaprio) says to Rose DeWitt Bukater (Kate Winslet) to get ready to swim, because the sinking body will suck them into the abysses. Is this sucking phenomenon really happening? And, if so, why?

  10. The lakes of Titan

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.; Elachi, C.; Lunine, J. I.; Lorenz, R. D.; Stiles, B.; Mitchell, K. L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W. T. K.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.

    2007-01-01

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70° north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface `liquid methane' table.

  11. Frozen Hydrocarbon Ponds on Titan: Implications for Titan’s Lakes and Seas

    NASA Astrophysics Data System (ADS)

    Soderblom, Jason M.; Barnes, Jason W.; Brown, Robert H.; Hayes, Alexander G.; Perry, Jason E.; Soderblom, Laurence A.; Turtle, Elizabeth P.

    2014-11-01

    Cassini Imaging Science Subsystem (ISS) observations have detected widespread darkening of Titan’s surface believed to be the result of rainfall: in 2005 at Arrakis Planitia, near Titan’s south pole (Turtle et al., 2009, GRL 36, L02204), and in 2009 in Titan’s tropics (Turtle et al., 2011, Science 331, 1414-1417). Cassini Visual and Infrared Mapping Spectrometer (VIMS) and ISS observations revealed that, following the tropics storm, the albedo of the wetted surfaces increased, beyond even their original albedo, then slowly faded back to a pre-rain brightness over ~10 months (Barnes et al., 2013, Planet. Sci. 2, 1). Herein we report on combined analysis of Cassini VIMS, Synthetic Aperture Radar (SAR), and ISS observations of Arrakis Planitia acquired in the years following the 2005 precipitation event. The low-albedo surface (observed in 2005 ISS images) correlates with local topography (inferred from 2008 SAR data), consistent with a liquid that has pooled on the surface. Like the equatorial event, the low-albedo surface at Arrakis Planitia is observed in VIMS data acquired from 2007 to 2009 to increase in albedo. Unlike the tropics event, however, four years after the initial precipitation event (more than 2 years after the increased albedo was first observed), these south-polar regions were still bright compared to their pre-precipitation albedo. The combined results support the hypothesis that hydrocarbons rained onto Titan’s surface and subsequently froze. Furthermore, because Titan's lakes and seas are almost certainly liquid, our results imply that some mechanism is preventing Titan's lakes and seas from freezing - one obvious hypothesis is that Titan’s lakes and seas differ in composition from Titan’s presumed methane-rich rain (likely the result of the concentration of minor constituents).

  12. Hydrocarbon Trapping in Titan Surface Materials

    NASA Astrophysics Data System (ADS)

    Cable, M. L.; Vu, T.; Choukroun, M.; Markus, C.; Hodyss, R.; Beauchamp, P.

    2014-02-01

    Benzene is found on Titan and is probably one of the most abundant evaporites to form around Titan lakes. We discovered trapping of ethane in crystalline benzene at 90 K, suggesting evaporite basins could act as hydrocarbon reservoirs on Titan.

  13. Titanic Weather Forecasting

    NASA Astrophysics Data System (ADS)

    2004-04-01

    New Detailed VLT Images of Saturn's Largest Moon Optimizing space missions Titan, the largest moon of Saturn was discovered by Dutch astronomer Christian Huygens in 1655 and certainly deserves its name. With a diameter of no less than 5,150 km, it is larger than Mercury and twice as large as Pluto. It is unique in having a hazy atmosphere of nitrogen, methane and oily hydrocarbons. Although it was explored in some detail by the NASA Voyager missions, many aspects of the atmosphere and surface still remain unknown. Thus, the existence of seasonal or diurnal phenomena, the presence of clouds, the surface composition and topography are still under debate. There have even been speculations that some kind of primitive life (now possibly extinct) may be found on Titan. Titan is the main target of the NASA/ESA Cassini/Huygens mission, launched in 1997 and scheduled to arrive at Saturn on July 1, 2004. The ESA Huygens probe is designed to enter the atmosphere of Titan, and to descend by parachute to the surface. Ground-based observations are essential to optimize the return of this space mission, because they will complement the information gained from space and add confidence to the interpretation of the data. Hence, the advent of the adaptive optics system NAOS-CONICA (NACO) [1] in combination with ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile now offers a unique opportunity to study the resolved disc of Titan with high sensitivity and increased spatial resolution. Adaptive Optics (AO) systems work by means of a computer-controlled deformable mirror that counteracts the image distortion induced by atmospheric turbulence. It is based on real-time optical corrections computed from image data obtained by a special camera at very high speed, many hundreds of times each second (see e.g. ESO Press Release 25/01 , ESO PR Photos 04a-c/02, ESO PR Photos 19a-c/02, ESO PR Photos 21a-c/02, ESO Press Release 17/02, and ESO Press Release 26/03 for earlier NACO images, and ESO Press Release 11/03 for MACAO-VLTI results.) The southern smile ESO PR Photo 08a/04 ESO PR Photo 08a/04 Images of Titan on November 20, 25 and 26, 2002 Through Five Filters (VLT YEPUN + NACO) [Preview - JPEG: 522 x 400 pix - 40k] [Normal - JPEG: 1043 x 800 pix - 340k] [Hires - JPEG: 2875 x 2205 pix - 1.2M] Caption: ESO PR Photo 08a/04 shows Titan (apparent visual magnitude 8.05, apparent diameter 0.87 arcsec) as observed with the NAOS/CONICA instrument at VLT Yepun (Paranal Observatory, Chile) on November 20, 25 and 26, 2003, between 6.00 UT and 9.00 UT. The median seeing values were 1.1 arcsec and 1.5 arcsec respectively for the 20th and 25th. Deconvoluted ("sharpened") images of Titan are shown through 5 different narrow-band filters - they allow to probe in some detail structures at different altitudes and on the surface. Depending on the filter, the integration time varies from 10 to 100 seconds. While Titan shows its leading hemisphere (i.e. the one observed when Titan moves towards us) on Nov. 20, the trailing side (i.e the one we see when Titan moves away from us in its course around Saturn) - which displays less bright surface features - is observed on the last two dates. ESO PR Photo 08b/04 ESO PR Photo 08b/04 Titan Observed Through Nine Different Filters on November 26, 2002 [Preview - JPEG: 480 x 400 pix - 36k] [Normal - JPEG: 960 x 800 pix - 284k] Caption: ESO PR Photo 08b/04: Images of Titan taken on November 26, 2002 through nine different filters to probe different altitudes, ranging from the stratosphere to the surface. On this night, a stable "seeing" (image quality before adaptive optics correction) of 0.9 arcsec allowed the astronomers to attain the diffraction limit of the telescope (0.032 arcsec resolution). Due to these good observing conditions, Titan's trailing hemisphere was observed with contrasts of about 40%, allowing the detection of several bright features on this surface region, once thought to be quite dark and featureless. ESO PR Photo 08c/04 ESO PR Photo 08c/04 Titan Surface Projections [Previ

  14. Self power generating piezoelectric elements applied to switching circuits

    NASA Astrophysics Data System (ADS)

    Imai, T.; Fujimoto, S.; Ichiki, M.

    2014-11-01

    In this study, we focused on lead zirconate titanate (PZT) as a power generating piezoelectric element. Niobium was added to each of the PZT elements to improve their power generation characteristics. The purpose of the study was to develop a high-efficiency PZT generator element that utilizes the vibration loads in the support members of a structure. We have previously reported the power generation characteristics of laminated PZT elements under vibration loads. Effect of vibration load, vibration frequency and number of PZT layers on generation characteristics of PZT elements was evaluated in the vibration test. We evaluate the power generation of laminated PZT elements and present the results of an experiment using a switching circuit as a load circuit in order to confirm the suitability of the laminated PZT element as a power source.

  15. Titanates and Titanate-Metal Compounds in Biological Contexts

    PubMed Central

    Chen, Yen-Wei; Drury, Jeanie L.; Chung, Whasun Oh; Hobbs, David T.; Wataha, John C.

    2015-01-01

    Metal ions are notorious environmental contaminants, some causing toxicity at exquisitely low (ppm-level) concentrations. Yet, the redox properties of metal ions make them attractive candidates for bio-therapeutics. Titanates are insoluble particulate compounds of titanium and oxygen with crystalline surfaces that bind metal ions; these compounds offer a means to scavenge metal ions in environmental contexts or deliver them in therapeutic contexts while limiting systemic exposure and toxicity. In either application, the toxicological properties of titanates are crucial. To date, the accurate measurement of the in vitro toxicity of titanates has been complicated by their particulate nature, which interferes with many assays that are optical density (OD)-dependent, and at present, little to no in vivo titanate toxicity data exist. Compatibility data garnered thus far for native titanates in vitro are inconsistent and lacking in mechanistic understanding. These data suggest that native titanates have little toxicity toward several oral and skin bacteria species, but do suppress mammalian cell metabolism in a cells-pecific manner. Titanate compounds bind several types of metal ions, including some common environmental toxins, and enhance delivery to bacteria or cells. Substantial work remains to address the practical applicability of titanates. Nevertheless, titanates have promise to serve as novel vehicles for metal-based therapeutics or as a new class of metal scavengers for environmental applications. PMID:26430701

  16. Electric properties and phase transition behavior in lead lanthanum zirconate stannate titanate ceramics with low zirconate content

    NASA Astrophysics Data System (ADS)

    Zeng, Tao; Lou, Qi-Wei; Chen, Xue-Feng; Zhang, Hong-Ling; Dong, Xian-Lin; Wang, Gen-Shui

    2015-11-01

    The phase transitions, dielectric properties, and polarization versus electric field (P–E) hysteresis loops of Pb0.97La0.02(Zr0.42Sn0.58?xTix)O3 (0.13? x ?0.18) (PLZST) bulk ceramics were systematically investigated. This study exhibited a sequence of phase transitions by analyzing the change of the P–E hysteresis loops with increasing temperature. The antiferroelectric (AFE) to ferroelectric (FE) phase boundary of PLZST with the Zr content of 0.42 was found to locate at the Ti content between 0.14 and 0.15. This work is aimed to improve the ternary phase diagram of lanthanum-doped PZST with the Zr content of 0.42 and will be a good reference for seeking high energy storage density in the PLZST system with low-Zr content. Project supported by the National Natural Science Foundation of China (Grant Nos. 51202273, 11204304, and 11304334) and the Science and Technology Commission of Shanghai Municipality, China (Grant No. 14DZ2261000).

  17. Geochemical signatures and magmatic stability of terrestrial impact produced zircon

    NASA Astrophysics Data System (ADS)

    Wielicki, Matthew M.; Harrison, T. Mark; Schmitt, Axel K.

    2012-03-01

    Understanding the role of impacts on early Earth has major implications to near surface conditions, but the apparent lack of preserved terrestrial craters > 2 Ga does not allow a direct sampling of such events. Ion microprobe U-Pb ages, REE abundances and Ti-in-zircon thermometry for impact produced zircon are reported here. These results from terrestrial impactites, ranging in age from ~ 35 Ma to ~ 2 Ga, are compared with the detrital Hadean zircon population from Western Australia. Such comparisons may provide the only terrestrial constraints on the role of impacts during the Hadean and early Archean, a time predicted to have a high bolide flux. Ti-in-zircon thermometry indicates an average of 773 °C for impact-produced zircon, ~ 100 °C higher than the average for Hadean zircon crystals. The agreement between whole-rock based zircon saturation temperatures for impactites and Ti-in-zircon thermometry (at aTiO2 = 1) implies that Ti-in-zircon thermometry record actual crystallization temperatures for impact melts. Zircon saturation modeling of Archean crustal rock compositions undergoing thermal excursions associated with the Late Heavy Bombardment predicts equally high zircon crystallization temperatures. The lack of such thermal signatures in the Hadean zircon record implies that impacts were not a dominant mechanism of producing the preserved Hadean detrital zircon record.

  18. Micro-motion exposure method based on PZT piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Sun, Wenjun; Zhang, Mei-heng; Meng, Zhong

    2009-07-01

    There mainly is laser digital photofinishing technique and digital photofinishing technique based on LCD consisting of TFT and LCOS in the digital photofinishing field at the present time. The former have a good many merit such as wide color gamut, high processing rate, large output size and high brightness, but his cost is very high, his maintain technique being comparatively complex, that result in difficult use for people. The utilization ratio of the latter is low because of lower resolution and lower aperture ratio for LCD, but the digital photofinishing based on LCD have lower cost and higher utilization ration, being suitable for people's current standard of living. Considering above mentioned problem, a micro-motion exposure method based on PZT piezoelectric ceramics used in digital image photofinishing is presented. The two-dimension micro-motion exposure system consisting of PZT piezoelectric ceramics, LCD panel, polarizing film and spring strip is designed. By means of PZT piezoelectric ceramics the LCD panel is removed about the one half of the pixel size of the LCD panel for four times from the original place, at the same time imaging system is exposed four times at the printing paper. The software is used to control the time synchronization, the exposure time and motion range of the LCD panel. The system has advantages such as shorter response time than 0.1seconds, lesser motion error than 0.01 microns, high stability and repeatability. Experimental results show that the proposed micro-motion exposure method improve the picture brightness and enlarge output size, at the meantime reducing the cost of the system.

  19. Stratospheric Ices in Titan's Atmosphere

    NASA Astrophysics Data System (ADS)

    Barth, E. L.

    2015-10-01

    Observations from Cassini, Voyager, and groundbased data point to the condensation of trace species in Titan's atmosphere, including HCN, C2H5CN, HC3N, C2H2, C2H6, and C4N2. These and a dozen other species have now been added to the Titan CARMA microphysics model, which shows condensation occurring between about 60 and 100 km in Titan's atmosphere. Results on condensation altitudes as well as particle size will be presented, and implications for the optical properties of Titan's stratospheric aerosol particles will be discussed.

  20. STRENGTH PROPERTIES OF POLED PZT SUBJECTED TO BIAXIAL FLEXURAL LOADING IN HIGH ELECTRIC FIELD

    SciTech Connect

    Wang, Hong; Lin, Hua-Tay; Wereszczak, Andrew A

    2010-01-01

    Failure of poled PZT has been experimentally studied using ball-on-ring (BoR) biaxial flexure strength tests with an electric field concurrently applied. The as-received and aged PZTs were tested in high electric fields of -3 to 4 times the coercive field. Both the sign and the magnitude of electric field had a significant effect on the strength of poled PZT. A surface flaw type with a depth of around 18 m was identified as the strength limiter and responsible for the failure of the tested PZT. With a value of 0.76 MPa m1/2 in the open circle condition, the fracture toughness of the poled PZT was affected by an applied electric field just as the strength was affected. These results and observations have the potential to serve probabilistic reliability analysis and design optimization of multilayer PZT piezo actuators.

  1. Organic chemistry on Titan

    NASA Technical Reports Server (NTRS)

    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.

  2. Titanic exploration with GIS

    USGS Publications Warehouse

    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. RADAR Reveals Titan Topography

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

    2005-01-01

    The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

  4. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, Rayford G. (Bryan, TX); Dosch, Robert G. (Albuquerque, NM)

    1993-01-01

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  5. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, R.G.; Dosch, R.G.

    1993-01-05

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  6. A Prototype PZT Matrix Transducer With Low-Power Integrated Receive ASIC for 3-D Transesophageal Echocardiography.

    PubMed

    Chen, Chao; Raghunathan, Shreyas B; Yu, Zili; Shabanimotlagh, Maysam; Chen, Zhao; Chang, Zu-Yao; Blaak, Sandra; Prins, Christian; Ponte, Jacco; Noothout, Emile; Vos, Hendrik J; Bosch, Johan G; Verweij, Martin D; de Jong, Nico; Pertijs, Michiel A P

    2016-01-01

    This paper presents the design, fabrication, and experimental evaluation of a prototype lead zirconium titanate (PZT) matrix transducer with an integrated receive ASIC, as a proof of concept for a miniature three-dimensional (3-D) transesophageal echocardiography (TEE) probe. It consists of an array of 9 ×12 piezoelectric elements mounted on the ASIC via an integration scheme that involves direct electrical connections between a bond-pad array on the ASIC and the transducer elements. The ASIC addresses the critical challenge of reducing cable count, and includes front-end amplifiers with adjustable gains and micro-beamformer circuits that locally process and combine echo signals received by the elements of each 3 ×3 subarray. Thus, an order-of-magnitude reduction in the number of receive channels is achieved. Dedicated circuit techniques are employed to meet the strict space and power constraints of TEE probes. The ASIC has been fabricated in a standard [Formula: see text] CMOS process and consumes only 0.44 mW/channel. The prototype has been acoustically characterized in a water tank. The ASIC allows the array to be presteered across ±37(°) while achieving an overall dynamic range of 77 dB. Both the measured characteristics of the individual transducer elements and the performance of the ASIC are in good agreement with expectations, demonstrating the effectiveness of the proposed techniques. PMID:26540683

  7. Landscape Evolution of Titan

    NASA Technical Reports Server (NTRS)

    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.

  8. The Lakes of Titan

    NASA Astrophysics Data System (ADS)

    Lunine, J.; Stofan, E.; Elachi, C.; Lorenz, R.; Stiles, B.; Mitchell, K. L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Callahan, P.; Anderson, Y.; Allison, M.; Boehmer, R.; Encrenaz, P.; Flamini, E.; Franceschetti, G.; Gim, Y.; Hamilton, G.; Hensely, S.; Johnson, W. T.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.; Orosei, R.

    2006-12-01

    The Cassini Radar flyby of Saturn's moon Titan on 22 July 2006 (T16) provides compelling evidence for the presence of liquid lakes on the surface of Titan. The radar images polewards of 70°N show over 75 circular to irregular radar dark patches from 3 km to over 170 km across, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. Some patches are uniformly dark in appearance, with no measureable echo, while others vary in brightness. We interpret these as lakes based on their very low radar reflectivity and morphological similarities to lakes, including associated channels, location in topographic depressions and multiple shorelines. Lakes appear in a number of apparent states, including fully drained, partially dry and liquid-filled. These northern hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface `liquid methane' table.

  9. Poling process optimization of piezo nano composite PZT/polimer

    NASA Astrophysics Data System (ADS)

    Ridlo, M. Rosyid; Lestari, Titik; Mardiyanto, Oemry, Achiar

    2013-09-01

    The objective of poling process is to make the electric dipole directions to be parallel in the inside perovskite crystal of piezo materials. In simply way, poling was carried out by giving the two sides of a piezo material by highly electrical potential. More parallel of electrical dipoles, it is more strength the piezo characteristics. The optimization involved control of temperature, time depth and the electrical voltage. The samples was prepared by solgel method with precursor tetrabutyl titanat Ti(OC4H9)4, zirconium nitrat Zr(NO3)4?5H2O, Pb(CH3COO)2?3H2O and solution ethylene glycol. Molar ratio Pb:Zr:Ti = 1,1:0,52:0,48 with concidering lossed Pb. Result of solgel process is nano powder PZT. The formed nano powder PZT was then mixed with polimer PVDF and pressed 10 MPa at 150 °C with the size 15 mm in diameter. After poling, piezoelectric constant d33 was measured. The highest d33 = 45 pC/N was found at poling parameters V = 5 kV/ mm, T = 120 °C dan time depth = 1 hours.

  10. ORIGINAL PAPER Ti-in-zircon thermometry: applications and limitations

    E-print Network

    Meyers, Stephen R.

    measured by ion microprobe. Samples come from 45 different igneous rocks (365 zircons), as well as zircon). Samples were chosen to represent a large range of igneous rock compositions. Most of the zir- cons contain average: 653 ± 124°C (2 standard deviations, 60 zircons) for felsic to intermediate igneous rocks, 758

  11. Fission track dating of kimberlitic zircons

    USGS Publications Warehouse

    Haggerty, S.E.; Raber, E.; Naeser, C.W.

    1983-01-01

    The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206Pb and 238U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.3 ?? 6.5 m.y.), Orapa (87.4 ?? 5.7 and 92.4 ?? 6.1 m.y.), Nzega (51.1 ?? 3.8 m.y.), Koffiefontein (90.0 ?? 8.2 m.y.), and Val do Queve (133.4 ?? 11.5 m.y.). In addition we report the first radiometric ages (707.9 ?? 59.6 and 705.5 ?? 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption. ?? 1983.

  12. Titan's Methane Cycle is Closed

    NASA Astrophysics Data System (ADS)

    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.

  13. Synthesis of nanosized sodium titanates

    DOEpatents

    Hobbs, David T.; Taylor-Pashow, Kathryn M. L.; Elvington, Mark C.

    2015-09-29

    Methods directed to the synthesis and peroxide-modification of nanosized monosodium titanate are described. Methods include combination of reactants at a low concentration to a solution including a nonionic surfactant. The nanosized monosodium titanate can exhibit high selectivity for sorbing various metallic ions.

  14. Zircon Th/U ratios in magmatic environs

    NASA Astrophysics Data System (ADS)

    Kirkland, C. L.; Smithies, R. H.; Taylor, R. J. M.; Evans, N.; McDonald, B.

    2015-01-01

    A comprehensive database of zircon composition in West Australian magmatic rocks reveals negative correlations between both U and Th zircon/whole rock ratio and the zircon saturation temperature, with the observed change with temperature less for U(zircon/whole rock) than for Th(zircon/whole rock). This observation implies a systematic increase in the zircon/rock ratio with falling crystallisation temperature, a result which replicates findings from experimental partition coefficient studies. Under equilibrium conditions there is a trend to lower zircon Th/U with increasing melt temperature which can be attributed to lattice strain. However, within a fractionating magma, Ti-in-zircon temperatures yield the opposite relationship of lower zircon Th/U in cooler melts. This is due to zircon growth under non-equilibrium conditions with greater incompatibility of Th relative to U, and the removal and segregation of mineral precipitates. These observations can be used as a tool to determine whether zircon growth was in a liquid of similar composition to the observed whole rock. We present an equation that estimates the degree of fractionation between the whole rock composition and the zircon parental liquid. This parameter demonstrates the dissimilarity between the liquid from which the zircon grew and the whole rock composition and aids in distinguishing mesostasis growth in fractionated melt versus cumulate growth in less fractionated magma. We use this ratio to investigate zircon growth in igneous rocks of the Musgrave Province. For a suite of c. 1200 Ma magmas that become progressively more fractionated, based on whole rock La/Sm, the fractionation index demonstrates increasing compositional differences between the whole rock and the zircon growth liquid. In the most extreme case independent petrographic evidence indicates mesostasis growth of zircon, whereas in the least fractionated melt zircon growth is established to be close to equilibrium with a zircon saturation temperature of c. 900 °C likely being accurate. In contrast, zircon crystals from a rhyolite of the c. 1070 Ma Giles Supervolcano have distinctive compositional discordances indicative of antecrystic components. The fractionation factor in this rock implies some zircon growth under higher temperature conditions than the whole rock zircon saturation temperature.

  15. Ferroelectric/electrode interfaces: Polarization switching and reliability of PZT capacitors in nonvolatile memories

    NASA Astrophysics Data System (ADS)

    Chen, Ye (Mike)

    The objective of this work was to investigate how the interface between electrode and PZT influences the PZT capacitor reliability. In order to conduct a well controlled experiment only the top-electrode PZT film interface was modified to study its effect on switching characteristics (i.e. hysteresis loop), voltage switching endurance and polarization retention of state of the art MOCVD grown film (nominally identical). The polycrystalline PZT film (50 -- 90 nm thick) are dominantly tetragonal with small fractions of the rhombohedral phase. XPS analyses of the as-deposited PZT film found the existence of a Pb-rich carbonate surface layer on all PZT film provided by industrial collaborators. Using materials characterizations such as in-situ XPS and ARXPS in tandem with electrical measurements it was determined that the Pb-rich surface layer appears to be an engineered sacrificial layer, which is beneficial in maximizing the switchable polarization and in improving the endurance and opposite-state retention behavior of PZT based FRAM capacitors with Pt electrode. This is because the excess Pb on the PZT surface and the Pb in the surface PZT reacts readily with the Pt during the Pt top electrode deposition creating a Pb-deficient non-ferroelectric interface layer between the top electrode and the PZT film. ARXPS analyses showed that this defective layer was approximately one nanometer thick and this is consistent with the hysteresis loop measurements that indicated a similar interface layer thickness. Inferior switching endurance and polarization retention was found in PZT film with an engineered initial thicker defective interface layer (via a HNO3-clean of the PZT surface prior to the top electrode deposition). This could be due to the fact that this defective interface layer may have thickened during the voltage cycling and/or retention bake. The thickening could be caused by greater carrier trapping and/or interface reaction between the Pb and the Pt. This thickening effectively stretched out the hysteresis curve and decreased remanent polarization that can be measured. To further investigate the interface effect on the switching phenomena and ferroelectric reliability, a monolayer HfO2 interface layer (experimentally determined optimal thickness) was inserted between the Pt top electrode and the PZT film by depositing the HfO2 monolayer coat by atomic layer deposition prior to room temperature Pt electrode deposition. Materials and electrical measurements showed that most of the applied electrical field was lost over this engineered interface layer (lower dielectric material) if its thickness was greater than 5 nanometer, effectively eliminating the switching phenomena. However, PZT capacitor with the monolayer HfO2 coat showed improved switching endurance and polarization retention. This is consistent with the preceding discussion because the engineering HfO 2 interface layer may have prevented the thickening of the interface layer during cycling and retention bake. Lastly, it was determined that the superior switching characteristics and reliability found in nominally identical PZT film with IrO2 top electrode was due to the inert chemical interface between the PZT and the top electrode. In-situ XPS analyses did not find any chemical reaction between the Pb in PZT surface and the IrO2 during the simulated IrO2 deposition. This is consistent with the higher switching polarization and greater voltage switching endurance found in PZT film with IrO2 top electrode.

  16. Cathodoluminescence of radiation-induced zircon

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Y.; Nishido, H.; Kayama, M.; Noumi, Y.

    2013-12-01

    Zircon occurs as a common accessory mineral in igneous, metamorphic and sedimentary rocks, and maintains much information on thermal history, metamorphic process and natural radiation dose accumulated in the mineral. U-Pb zircon dating (e.g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) image has been used for identification of internal zones and domains having different chemical compositions and/or structures with a high spatial resolution. The CL of zircon is derived from various types of emission centers, which are derived from impurities such as rare earth elements (REE) and structural defects. In fact, the CL features of zircon are closely related to metamorphic process and radiation from contained radionuclides as well as geochemical condition of its formation. Most zircon has yellow emission, which seems to be assigned to UO2 centers or radiation-induced defect during metamictization of the lattice by alpha particles from the decay of U and Th. In this study, the radiation effects on zircon CL have been studied for He+ ion-implanted samples annealed at various temperatures to clarify radiation-induced defect centers involved with the yellow CL emission in zircon. Single crystals of zircon from Malawi (MZ), Takidani granodiorite (TZ) and Kurobegawa granite (KZ) were selected for He+ ion implantation experiments. The polished plates of the samples were implanted by He+ ion 4.0 MeV corresponding to energy of alpha particle from 238 U and 232Th. CL spectra in the range from 300 to 800 nm with 1 nm step were measured by a scanning electron microscopy-cathodoluminescence (SEM-CL). CL spectra of untreated and annealed zircon show emission bands at ~370 nm assigned to intrinsic defect centers and at ~480, ~580 and ~760 nm to trivalent Dy impurity centers (Cesbron et al., 1995; Gaft et al, 2005). CL emissions in the yellow-region were observed in untreated zircon. The TZ and KZ indicate youngest formation ages of 1.93-1.20 Ma and 1.7-0.9 Ma, respectively (Harayama,1994; Harayama et al., 2010) in the world. In this case, it is hardly to detect yellow CL emissions derived from radiation-induced defect center, suggesting low radiation dose of alpha radiation from 238U and 232Th on them. CL spectra of MZ, TZ and KZ showed an increase in the intensities of yellow emissions with an increase in radiation dose of He+ ion implantation, though He+ ion implantation reduces the intensities of their impurity centers. CL intensity in the yellow region depends on radiation dose of He+ ion implantation. Therefore, if the component of yellow emission could be deconvoluted from the CL spectra in zircon, its intensity will be used for an indicator to evaluate total exposure doses on it during geological age.

  17. Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer layers

    E-print Network

    Alpay, S. Pamir

    Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer in their PE state. One of the leading material candidates for tunable materials is barium strontium titanate

  18. Titan's atmosphere from DISR

    NASA Astrophysics Data System (ADS)

    West, Robert

    This abstract distills information about Titan's atmosphere described in detail in a paper by M. G. Tomasko, L. Doose, S. Engel, L. E. Dafoe, R. West, M. Lemmon, E. Karkoschka and C. See, ‘A model of Titan's aerosols based on measurements made inside the atmosphere', Planetary and Space Sciences, in press, 2008. The Descent Imager Spectral Radiometer (DISR) observed Titan's sky and surface during the descent of the Huygens Probe in January, 2005. Measurements were made over the altitude range 160 Km to the surface near latitude -10 degrees. The DISR instrument package included several components to measure the radiation state as a function of altitude. These include upward and downward-looking visible and near-infrared spectrometers covering the wavelength range 450 to 1600 nm, an ultraviolet photometer, a solar aureole camera with polarizers, and a sun sensor. Measurements were made at a variety of azimuthal angles relative to the sun azimuth. Due to unanticipated behavior of the probe (reverse spin and high-amplitude, chaotic tip and tilt) the retrieval process has required more effort than was planned and the total science return is less than expected. Nevertheless the data yielded unsurpassed and unique information which constrain the optical and physical properties of the photochemical haze aerosols and condensate particles. The principal findings are (1) between 80 Km and 160 Km the photochemical haze is well mixed with the gas with a scale height of about 65 Km, (2) between 80 Km and the surface the particle optical depth is a linear function of altitude with a break in slope near 30 Km altitude, (3) optical properties of the haze do not depend much on altitude above 80 Km although more recent work by Tomasko and colleagues suggest a gradient in the stratosphere; below 80 Km there are changes in optical behavior which suggest that condensation plays a role, (4) the data confirm previous results which proposed a particle structure of aggregates of small monomers, but the DISR data indicate somewhat smaller monomer radius ( 0.05 micro meters) and many more total monomers ( 3000) in the average particle, and (5) above 80 Km altitude particle refractive indices are similar to what is expected from laboratory measurements for tholin (Khare, B. N., Sagan, C., Arakawa, E. T., Suits, F., Calcott, T. A., Williams, M. W., ‘Optical constants of organic tholins produced in a simulated Titanian atmosphere: from X-ray to microwave frequencies', Icarus 60, 127-137, 1984) but below 80 Km there is less absorption suggesting that condensates play a role. The analyses of DISR data also led to a revision of near-infrared methane absorption coefficients under Titan conditions (M. G. Tomasko, B. Bézard , L. Doose, S. Engel, and E. Karkoschka, e ‘Measurements of Methane Absorption by the Descent Imager/Spectral Radiometer (DISR) During its Descent through Titan's Atmosphere', Planetary and Space Sciences, in press, 2008) and to a much-improved determination of the radiation budget which is important for dynamics and climate studies (M. G. Tomasko, B. Bézard , L. Doose, S. Engel, E. Karkoschka and S. e Vinatier, ‘Heat Balance in Titan's Atmosphere', Planetary and Space Sciences, in press, 2008).

  19. Zinc titanate sorbents

    DOEpatents

    Gupta, Raghubir P. (Durham, NC); Gangwal, Santosh K. (Durham, NC); Jain, Suresh C. (Germantown, MD)

    1998-01-01

    The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750.degree. C. to about 950.degree. C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 .mu., and about 1 part titanium dioxide having a median particle size of less than about 1 .mu.. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

  20. Zinc titanate sorbents

    DOEpatents

    Gupta, R.P.; Gangwal, S.K.; Jain, S.C.

    1998-02-03

    The present invention provides a zinc titanate sorbent material useful in desulfurization applications. The zinc titanate material is in the form of generally spherical particles of substantially uniform chemical distribution. The sorbent material is capable of absorbing sulfur compounds from a gaseous feed in an amount of at least about 15 weight percent based on the weight of the sorbent. The sorbent material is prepared by a process including: (a) forming a zinc oxide/titanium dioxide dry blend, (b) preparing a substantially uniform aqueous slurry comprising the zinc oxide/titanium dioxide dry blend, organic binder, and at least about 1 weight percent inorganic binder based on the solids weight of the slurry, (c) spray drying the slurry to produce substantially spherical particles, and (d) calcining the particles at a temperature of between about 750 to about 950 C. The dry blend is formed by mixing between about 0.5 to about 2 parts zinc oxide having a median particle size of less than about 0.5 microns, and about 1 part titanium dioxide having a median particle size of less than about 1 micron. The slurry contains substantially no free silica and may be prepared by the process including (1) preparing an aqueous solution of organic binder, (2) adding the dry blend to the aqueous solution of organic binder, and (3) adding the inorganic binder to the solution of organic binder, and blend. Additional reagents, such as a surfactant, may also be incorporated into the sorbent material. The present invention also provides a process for desulfurizing a gaseous stream. The process includes passing a gaseous stream through a reactor containing an attrition resistant zinc titanate sorbent material of the present invention.

  1. Model-Based, Closed-Loop Control of PZT Creep for Cavity Ring-Down Spectroscopy

    PubMed Central

    McCartt, A D; Ognibene, T J; Bench, G; Turteltaub, K W

    2014-01-01

    Cavity ring-down spectrometers typically employ a PZT stack to modulate the cavity transmission spectrum. While PZTs ease instrument complexity and aid measurement sensitivity, PZT hysteresis hinders the implementation of cavity-length-stabilized, data-acquisition routines. Once the cavity length is stabilized, the cavity’s free spectral range imparts extreme linearity and precision to the measured spectrum’s wavelength axis. Methods such as frequency-stabilized cavity ring-down spectroscopy have successfully mitigated PZT hysteresis, but their complexity limits commercial applications. Described herein is a single-laser, model-based, closed-loop method for cavity length control. PMID:25395738

  2. Mechanism of hydrothermal growth of ferroelectric PZT nanowires

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Durussel, Alexandre; Sandu, Cosmin Silviu; Sahini, Mtabazi Geofrey; He, Zhangbing; Setter, Nava

    2012-05-01

    The formation mechanism of hydrothermally grown monocrystalline ferroelectric PZT nanowires is investigated. It is shown that the growth proceeds via a two-step process. Particles of the centrosymmetric PX-phase grow initially, having a fibrous morphology which is compatible with the highly anisotropic crystalline structure of this material. In the second stage, the PX-phase transforms into the ferroelectric perovskite phase, retaining the initial fibrous morphology. The solubility limit of Zr ions in the PX phase is maintained into the perovskite phase. While the PX and the perovskite phases have a similar composition, the reconstructive transformation process, in which edge-sharing octahedra chains of the PX-phase transform into a 3D network of corner sharing octahedra in the perovskite, involves incorporation and then release of oxygen (or hydroxyl).

  3. Touchdown on Titan

    NASA Technical Reports Server (NTRS)

    Morring, Frank, Jr.

    2004-01-01

    Europe's Huygens probe is on target for a Dec. 25 separation from the Cassini Saturn orbiter that has carried it like a baby for more than seven years. The probe will spend three weeks coasting to a plunge into Titan's thick atmosphere on the morning of Jan. 14. If all goes as planned, the 349-kg. Huygens will spend more than 2 hr. descending by parachute to the mysterious surface of the planet-sized moon, and hopefully devote yet more time to broadcasting data after it lands. Before the day is over, Huygens is programmed to beam about 30 megabytes of data - including some 1,100 images-back to Earth through Cassini, a trip that will take some 75 min. to complete over the 1- billion-km. distance that separates the two planets. Within that data should be answers to questions that date back to 1655, when Dutch astronomer Christiaan Huygens found the moon with a homemade telescope and named it for the family of giants the ancient Greeks believed once ruled the earth. In the Solar System, there is no other world like Titan, with a nitrogen and methane atmospheric and a cold, hidden surface darker than Earth under the full Moon.

  4. Fabrication and Characterization of PZT Thin-Film on Bulk Micromachined Si Motion Detectors

    SciTech Connect

    Clem, P.; Garino, T.J.; Laguna, G.; Tuttle, B.A.

    1999-01-07

    Motion detectors consisting of Pb(Zr{sub x}Ti{sub (1{minus}x)})O{sub 3} (PZT) thin films, between platinum electrodes, on micromachined silicon compound clamped-clamped or cantilever beam structures were fabricated using either hot KOH or High Aspect Ratio Silicon Etching (HARSE) to micromachine the silicon. The beams were designed such that a thicker region served as a test mass that produced stress at the top of the membrane springs that supported it when the object to which the detector was mounted moved. The PZT film devices were placed on these membranes to generate a charge or a voltage in response to the stress through the piezoelectric effect. Issues of integration of the PZT device fabrication process with the two etching processes are discussed. The effects of PZT composition and device geometry on the response of the detectors to motion is reported and discussed.

  5. CHARACTERIZATION OF POLED SINGLE-LAYER PZT FOR PIEZO STACK IN FUEL INJECTION SYSTEM

    SciTech Connect

    Wang, Hong; Matsunaga, Tadashi; Lin, Hua-Tay

    2010-01-01

    Poled single-layer PZT has been characterized in as-extracted and as-received states. PZT plate specimens in the former were extracted from a stack. Flexure strength of PZT was evaluated by using ball-on-ring and 4-point bend tests. Fractography showed that intergranular fractures dominated the fracture surface and that volume pores were the primary strength-limiting flaws. The electric field effect was investigated by testing the PZT in open circuit and coercive field levels. An asymmetrical response on the biaxial flexure strength with respect to the electric field direction was observed. These experimental results will assist reliability design of the piezo stack that is being considered in fuel injection system.

  6. Properties of PZT-Based Piezoelectric Ceramics Between -150 and 250 C

    NASA Technical Reports Server (NTRS)

    Hooker, Matthew W.

    1998-01-01

    The properties of three PZT-based piezoelectric ceramics and one PLZT electrostrictive ceramic were measured as a function of temperature. In this work, the dielectric, ferroelectric polarization versus electric field, and piezoelectric properties of PZT-4, PZT-5A, PZT-5H, and PLZT-9/65/35 were measured over a temperature range of -150 to 250 C. In addition to these measurements, the relative thermal expansion of each composition was measured from 25 to 600 C and the modulus of rupture of each material was measured at room temperature. This report describes the experimental results and compares and contrasts the properties of these materials with respect to their applicability to intelligent aerospace systems.

  7. The conductivity mechanism and an improved C-V model of ferroelectric PZT thin film

    NASA Astrophysics Data System (ADS)

    Liang, K.; Buditama, A.; Chien, D.; Cui, J.; Cheung, P. L.; Goljahi, S.; Tolbert, S. H.; Chang, J. P.; Lynch, C. S.

    2015-05-01

    A dense, homogeneous and crack-free ferroelectric PZT thin film with <100>-preferred orientation was produced using the sol-gel method. The volume fraction ?(100) of <100>-oriented grains in the PZT film was calculated [?(100) ? 80%] from XRD of the PZT thin film and powder. The PZT thin film exhibits an open polarization vs. electric field loop and a low leakage current density from 10-8 A/cm2 to 10-7 A/cm2. The electrical conduction data were fit to a Schottky-emission model with deep traps from 100 kV/cm to 250 kV/cm. A modified capacitance model was introduced that adds electrical domain capacitance based on a metal-ferroelectric-metal (MFM) system with Schottky contacts. The model reproduces the observed non-linear capacitance vs. voltage behavior of the film.

  8. Active buckling control of smart plate as diaphragm with PZT5 sensor/actuator patches

    NASA Astrophysics Data System (ADS)

    Viliani, N. S.; Pourrostami, H.; Mostafavi, S. M.; Hashemizadeh, F.; Safian, M. R.; Hashemi, M.

    2014-12-01

    In current study, buckling analyses of smart plate is presented. The various types of piezoelectric materials are under investigation for petrochemical industry and other applications. The PZT sensor output is used to determine the input to the PZT actuator using the feedback control algorithm for buckling control of FG plate. This study investigated the governing differential equations of motion of smart plate which includes FG plate as the membrane and PZT5 patches as actuator and sensor. The Fourier series method adopted to obtain the solution for the equation of motion. Also the effects of feedback gain and FGM volume fraction exponent on the critical buckling load for PZT-5A are studied. The potential application of current study can be found in optimal design of sensor's diaphragm. The variation of critical buckling load vs. feedback gain indicates that by increasing the feedback gain, the buckling load increases.

  9. Micro-Machined High-Frequency (80 MHz) PZT Thick Film Linear Arrays

    PubMed Central

    Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K. Kirk

    2010-01-01

    This paper presents the development of a micro-machined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 ?m and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT solgel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (?6 dB) of 60%. An insertion loss of ?41 dB and adjacent element crosstalk of ?21 dB were found at the center frequency. PMID:20889407

  10. Constraints on Hadean zircon protoliths from oxygen isotopes, Ti-thermometry, and rare earth elements

    E-print Network

    Mojzsis, Stephen J.

    zircon oxygen isotope ratios and reconnaissance Ti-in-zircon concentrations, guidedConstraints on Hadean zircon protoliths from oxygen isotopes, Ti-thermometry, and rare earth Australia. Zircon oxygen isotope results bolster the view that some Hadean (>3.85 Ga) zircon source melts

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

    SciTech Connect

    Not Available

    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.

  12. Titan's greenhouse and antigreenhouse effects

    NASA Technical Reports Server (NTRS)

    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.

  13. Seasonal Changes in Titan's Meteorology

    NASA Technical Reports Server (NTRS)

    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

  14. Ices in Titan's Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Anderson, Carrie

    2010-01-01

    Analyses of Cassini CIRS far-infrared limb spectra of Titan at 15N, 15S, and 58S reveal a broad emission feature between 70 and 270/cm, restricted to altitudes between 60 and 100 km. This emission feature is chemically different from Titan's photochemical aerosol, which has an emission feature peak around 145 cm-1. The shape of the observed broad emission feature resembles a mixture of the solid component of the two most abundant nitrites in Titan's stratosphere, that of HCN and HC3N. Following the saturation vapor pressure vertical profiles of HCN and HC3N, the 60 to 100 km altitude range corresponds closely to the vertical location where these nitriles are expected to condense out and form small, suspended ice particles. This is the first time ices in Titan's stratosphere have been identified at latitudes south of 50N. Results and physical implications will be discussed.

  15. Fluctus and Virgae of Titan

    NASA Astrophysics Data System (ADS)

    Wood, C. A.; Stofan, E. R.; Paganelli, F.; Lorenz, R. D.

    2009-03-01

    Fluctus are bright flows on Titan with lobate margins and linear sources. If they are volcanic features they are evidence for tectonic control. Shiwanni Virgae is dune material that diverts around obstacles. They are not tectonic.

  16. Zircon 4He/3He thermochronometry

    NASA Astrophysics Data System (ADS)

    Tripathy-Lang, Alka; Fox, Matthew; Shuster, David L.

    2015-10-01

    Multiple thermochronometric methods are often required to constrain time-continuous rock exhumation for studying tectonic processes or development of km-scale topography at Earth's surface. Here, we explore 4He/3He thermochronometry of zircon as a method for constraining continuous time-temperature (t-T) paths of individual samples through a temperature range that is complementary to methods such as 40Ar/39Ar thermochronometry of K-feldspar and 4He/3He thermochronometry of apatite. For different cooling rates and diffusion domain size, the temperature sensitivity of zircon 4He/3He thermochronometry ranges from slightly less than 100 °C to slightly greater than 250 °C; a typical sample provides continuous thermal constraints over ?100 °C within that range. Outside these temperatures, 4He in zircon will either be quantitatively retained or completely lost by volume diffusion. As proof-of-concept, we present stepwise release 4He/3He spectra and associated U and Th concentration maps measured by laser ablation ICP-MS analysis of individual crystal aliquots of Fish Canyon Tuff (FCT) zircon and of a more complex setting in the Sierra Nevada batholith that experienced reheating from a proximal basaltic intrusion, the Little Devil's Postpile (LDP). The FCT zircon 4He/3He release spectra are consistent with a 4He spatial distribution dominated by alpha-ejection from crystal surfaces. The spatial distributions of U and Th measured in the same crystals do not substantially influence 4He/3He release spectra that are predicted for the known thermal history, even when incorporating spatially variable diffusivity due to accumulation of radiation damage. Conversely, the LDP 4He/3He release spectra are strongly influenced by the observed parent nuclide zonation. A three-dimensional (3D) numerical model of 4He production and diffusion, which incorporates crystal geometry, U and Th zonation, and spatially variable He diffusion kinetics, substantially improves the fit between measured and modeled 4He/3He release spectra for the independently known thermal history of the sample. We conclude that zircon 4He/3He thermochronometry provides accurate thermal constraints through geologic time, but certain applications of this technique may require 3D numerical modeling approaches.

  17. Strain mediated coupling in magnetron sputtered multiferroic PZT/Ni-Mn-In/Si thin film heterostructure

    SciTech Connect

    Singh, Kirandeep; Kaur, Davinder; Singh, Sushil Kumar

    2014-09-21

    The strain mediated electrical and magnetic properties were investigated in PZT/Ni-Mn-In heterostructure deposited on Si (100) by dc/rf magnetron sputtering. X-ray diffraction pattern revealed that (220) orientation of Ni-Mn-In facilitate the (110) oriented tertragonal phase growth of PZT layer in PZT/Ni-Mn-In heterostructure. A distinctive peak in dielectric constant versus temperature plots around martensitic phase transformation temperature of Ni-Mn-In showed a strain mediated coupling between Ni-Mn-In and PZT layers. The ferroelectric measurement taken at different temperatures exhibits a well saturated and temperature dependent P-E loops with a highest value of P{sub sat}~55 ?C/cm² obtained during martensite-austenite transition temperature region of Ni-Mn-In. The stress induced by Ni-Mn-In layer on upper PZT film due to structural transformation from martensite to austenite resulted in temperature modulated Tunability of PZT/Ni-Mn-In heterostructure. A tunability of 42% was achieved at 290 K (structural transition region of Ni-Mn-In) in these heterostructures. I-V measurements taken at different temperatures indicated that ohmic conduction was the main conduction mechanism over a large electric field range in these heterostructures. Magnetic measurement revealed that heterostructure was ferromagnetic at room temperature with a saturation magnetization of ~123 emu/cm³. Such multiferroic heterostructures exhibits promising applications in various microelectromechanical systems.

  18. Strain mediated coupling in magnetron sputtered multiferroic PZT/Ni-Mn-In/Si thin film heterostructure

    NASA Astrophysics Data System (ADS)

    Singh, Kirandeep; Singh, Sushil Kumar; Kaur, Davinder

    2014-09-01

    The strain mediated electrical and magnetic properties were investigated in PZT/Ni-Mn-In heterostructure deposited on Si (100) by dc/rf magnetron sputtering. X-ray diffraction pattern revealed that (220) orientation of Ni-Mn-In facilitate the (110) oriented tertragonal phase growth of PZT layer in PZT/Ni-Mn-In heterostructure. A distinctive peak in dielectric constant versus temperature plots around martensitic phase transformation temperature of Ni-Mn-In showed a strain mediated coupling between Ni-Mn-In and PZT layers. The ferroelectric measurement taken at different temperatures exhibits a well saturated and temperature dependent P-E loops with a highest value of Psat ˜ 55 ?C/cm2 obtained during martensite-austenite transition temperature region of Ni-Mn-In. The stress induced by Ni-Mn-In layer on upper PZT film due to structural transformation from martensite to austenite resulted in temperature modulated Tunability of PZT/Ni-Mn-In heterostructure. A tunability of 42% was achieved at 290 K (structural transition region of Ni-Mn-In) in these heterostructures. I-V measurements taken at different temperatures indicated that ohmic conduction was the main conduction mechanism over a large electric field range in these heterostructures. Magnetic measurement revealed that heterostructure was ferromagnetic at room temperature with a saturation magnetization of ˜123 emu/cm3. Such multiferroic heterostructures exhibits promising applications in various microelectromechanical systems.

  19. From Titan's chemistry and exobiology to Titan's astrobiology

    NASA Astrophysics Data System (ADS)

    Raulin, François

    2015-04-01

    When the IDS proposal « Titan's chemistry and exobiology » was submitted to ESA 25 years ago, in the frame of what will become the Cassini-Huygens mission, Titan was already seen as a quite interesting planetary object in the solar system for Exobiology. Several organic compounds of prebiotic interest were identified in its atmosphere, which was thus was expected to be chemically very active, especially in term of organic processes. Atmospheric aerosols seemed to play a key role in this chemistry. Moreover, the presence of an internal aqueous ocean, compatible with life was suspected. A few years later, when astrobiology was (re)invented, Titan became one of the most interesting planetary target for this new (but very similar to exobiology) field. With the Cassini-Huygens mission, the exo/astrobiological interest of Titan has become more and more important. However, the mission has been providing a vision of Titan quite different from what it was supposed. Its atmospheric organic chemistry is very complex and starts in much higher zones than it was believed before, involving high molecular weight species in the ionosphere. Titan's surface appears to be far from homogeneous: instead of been covered by a global methane-ethane ocean, it is very diversified, with dunes, lakes, bright and dark areas, impact and volcanic craters with potential cryovolcanic activity. These various geological areas are continuously feeded by atmospheric aerosols, which represent an important step in the complexity of Titan's organic chemistry, but probably not the final one. Indeed, after being deposited on the surface, in the potential cryovolvanic zones, these particles may react with water ice and form compounds of exo/astrobiological interest, such as amino acids, purine and pyrimidine bases. Moreover, The Cassini-Huygens data strongly support the potential presence of an internal water ocean, which becomes less and less hypothetical and of great interest for exobiology. These various exobiological aspects of Titan, revealed from Cassini-Huygens observations, especially from the data of the Huygens instruments, coupled to laboratory works, both experimental simulations and modeling, will be quickely reviewed and summarized. References : Raulin, F. (2008), Astrobiology and habitability of Titan, Space Science Reviews 135 (1-4), 37-48 ; Raulin, F. et al. (2012), Prebiotic-like chemistry on Titan. Chemical Society Reviews. 41, 5380-5393 Acknowledgement: Supports from the European Space Agency (ESA) and the French Space Agency (CNES) is deeply acknowledged.

  20. Subterahertz excitations and magnetoelectric effects in hexaferrite-piezoelectric bilayers

    NASA Astrophysics Data System (ADS)

    Ustinov, Alexey B.; Srinivasan, G.

    2008-10-01

    A frequency-agile hexaferrite-piezoelectric composite for potential device applications at subterahertz frequencies is studied. The bilayer is composed of aluminum substituted barium hexagonal ferrite (BaAl2Fe10O19) and lead zirconate titanate (PZT). A dc electric field applied to PZT results in mechanical deformation of the ferrite, leading to a frequency shift in ferromagnetic resonance. The bilayer demonstrates magnetoelectric interaction coefficient of about 0.37Oecm/kV.

  1. Life on Titan

    NASA Astrophysics Data System (ADS)

    Potashko, Oleksandr

    Volcanoes engender life on heavenly bodies; they are pacemakers of life. All planets during their period of formation pass through volcanism hence - all planets and their satellites pass through the life. Tracks of life If we want to find tracks of life - most promising places are places with volcanic activity, current or past. In the case of just-in-time volcanic activity we have 100% probability to find a life. Therefore the most perspective “search for life” are Enceladus, Io and comets, further would be Venus, Jupiter’s satellites, Saturn’s satellites and first of all - Titan. Titan has atmosphere. It might be result of high volcanic activity - from one side, from other side atmosphere is a necessary condition development life from procaryota to eucaryota. Existence of a planet means that all its elements after hydrogen formed just there inside a planet. The forming of the elements leads to the formation of mineral and organic substances and further to the organic life. Development of the life depends upon many factors, e.g. the distance from star/s. The intensity of the processes of the element formation is inversely to the distance from the star. Therefore we may suppose that the intensity of the life in Mercury was very high. Hence we may detect tracks of life in Mercury, particularly near volcanoes. The distance from the star is only one parameter and now Titan looks very active - mainly due to interior reason. Its atmosphere compounds are analogous to comet tail compounds. Their collation may lead to interesting result as progress occurs at one of them. Volcanic activity is as a source of life origin as well a reason for a death of life. It depends upon the thickness of planet crust. In the case of small thickness of a crust the probability is high that volcanoes may destroy a life on a planet - like Noachian deluge. Destroying of the life under volcano influences doesn’t lead to full dead. As result we would have periodic Noachian deluge or nuclear winter. These events are known as extinctions or ice ages. The crust of a planet of the Earth group is formed at the outer edge of the body. The planets after asteroid belt like Jupiter or Saturn probably form their “crusts” in the centre of the body. Due to we may see internal kitchen of element forming in detail. This processes lead to the organic life, which we may detect at the atmospheres of Jupiter, Saturn, Neptune, and Pluto. But their satellites look like earth planet group - with outer crust. Huygens considered that God's wisdom and providence is clearest in the creation of life, and Earth holds no privileged position in the heavens that life must be universal. “Huygens” helps find life on Titan

  2. Hafnium isotopic heterogeneity in zircons from granitic rocks: Geochemical evaluation and modeling of “zircon effect” in crustal anatexis

    NASA Astrophysics Data System (ADS)

    Tang, Ming; Wang, Xiao-Lei; Shu, Xu-Jie; Wang, Di; Yang, Tao; Gopon, Phillip

    2014-03-01

    We carried out a geochemical evaluation and modeled the mechanism responsible for varied Hf isotopic ratios in magmatic zircons of a single granitic rock specimen. Five representative granitic samples were selected from southern China based on preliminary Hf isotopic data. Our new dataset of zircon Hf isotopes confirmed significant Hf-isotope variations (5-9 epsilon units) for each sample, and these zircons show roughly positive Th/U versus T (crystallizing temperature) correlations, while the Lu/Hf variation is independent from T. In addition, some zircons show significantly higher Ti concentrations in the rims compared to the interiors, implying reverse thermal zonation based on the Ti-in-zircon thermometry. These geochemical features in zircons suggest open-system processes which may have resulted from frequent replenishment. We modeled zircon dissolution during crustal anatexis to reveal the Hf isotopic evolution in the extracted melts. The model suggests that the extracted melts may have extremely variable Hf isotope compositions (>20 epsilon units) if the bulk Zr concentration in the source is initially above 100 ppm and the melting is rapid (>10-4 yr-1). The decoupled release of zircon Hf and non-zircon Hf from a single crust-derived magma source can lead to significant Hf-isotope variations in a solidified granitic body. This work provides an alternative explanation for the Hf isotopic heterogeneity in magmatic zircons of granitic rocks, which is in contrast to the common interpretation by mixing with mantle-derived magmas.

  3. A Raman spectroscopic study of zircons on micro-scale and Its significance in explaining the origin of zircons

    E-print Network

    Xuezhao Bao; Huiming Li; Songnian Lu

    2007-08-15

    The magmatic and metamorphic zircons were investigated with Raman spectrum microprobe analysis. We found notable differences between these two kinds of zircons exhibited by the variation trend of Raman peak intensity from core to rim of a crystal. In magmatic zircons, the intensity and the ratio H/W of Raman spectrum peaks gradually decrease from core to rim of a crystal, which is produced by an increase in metamictization degree and suggests an increase in U and Th concentrations from core to rim. In metamorphic zircons, there are two kinds of crystals according to their Raman spectra: the first group of zircons exhibits a variation trend opposite to those of magmatic zircons, tending to increase in the Raman peak intensity and H/W value from core to rim of a crystal, which is produced by a decrease in metamictization degree and indicates a decrease of U and Th concentrations from core to rim of a crystal. The second group of zircons exhibits no change in Raman peak intensity and H/W value through a crystal. The data of infrared and Raman spectra of these crystals show that they are well crystallized and have no lattice destruction induced by metamictization, and are thought to crystallize in high temperature stages of metamorphism. During these stages, the U and Th ions have been removed by metamorphic fluids from the parent rocks of these zircons. The other difference between magmatic and metamorphic zircons is the background level of their Raman spectra, which is high and sloped in magmatic zircons, but low and horizontal in metamorphic zircons. The differences between magmatic and metamorphic zircons can be used to identify the genesis of zircons and understand the origin and evolution history of their parent rocks.

  4. The crystallization age of eucrite zircon.

    PubMed

    Srinivasan, G; Whitehouse, M J; Weber, I; Yamaguchi, A

    2007-07-20

    Eucrites are a group of meteorites that represent the first planetary igneous activity following metal-silicate differentiation on an early planetesimal, similar to Asteroid 4 Vesta, and, thus, help date geophysical processes occurring on such bodies in the early solar system. Using the short-lived radionuclide (182)Hf as a relative chronometer, we demonstrate that eucrite zircon crystallized quickly within 6.8 million years of metal-silicate differentiation. This implies that mantle differentiation on the eucrite parent body occurred during a period when internal heat from the decay of (26)Al and (60)Fe was still available. Later metamorphism of eucrites took place at least 8.9 million years after the zircons crystallized and was likely caused by heating from impacts, or by burial under hot material excavated by impacts, rather than from lava flows. Thus, the timing of eucrite formation and of mantle differentiation is constrained. PMID:17641194

  5. Modeling of Carbochlorination of Zircon in Fluidized Bed Reactor

    NASA Astrophysics Data System (ADS)

    Jazini, M. H.; Ghoreishi, S. M.; Dadkhah, A. A.

    2010-02-01

    The chlorination of zircon is an integral part of the overall process for the production of zirconium. A two-phase hydrodynamic-type model was used to simulate the fluidized bed zircon carbochlorination reactor. In the plug-plug (P-P) model, the flow of gas in both dense and bubble phases was considered as a plug flow compared with the plug-mixed (P-M) model in which the flow in dense phase was assumed to be mixed. The zircon conversion obtained by model was compared with experimental measurements for model validation. The results of the P-M model indicated a stronger correlation with experimental data. Using the validated model, the effects of the zircon inlet size distribution, reactor temperature, inlet gas concentration, chlorine conversion velocity, and converted zircon were investigated. The results demonstrated that higher reactor temperature, smaller zircon size, and higher inlet gas velocity and concentration enhanced the chlorination rate.

  6. TITAN Overview 1 TITAN: A NextGeneration Infrastructure for Integrating

    E-print Network

    California at Berkeley, University of

    TITAN Overview 1 TITAN: A Next­Generation Infrastructure for Integrating Computing and communication infrastructure a new type of computing system, called Titan. This computing system comprises be examined on­line at URL http://www.cs/projects/titan/index.html In this report we outline the progress

  7. Nondetection of Titan lightning radio emissions with Cassini/RPWS after 35 close Titan flybys

    E-print Network

    Gurnett, Donald A.

    Nondetection of Titan lightning radio emissions with Cassini/RPWS after 35 close Titan flybys G on the nondetection of radio emissions associated with possible lightning flashes in Titan's atmosphere by the Cassini/RPWS (Radio and Plasma Wave Science) instrument. A valid proof for Titan lightning would be the detection

  8. Titan, Weird Chemistry, and Weird Life

    NASA Astrophysics Data System (ADS)

    Benner, S. A.; Kim, H.-J.

    2010-04-01

    Some hypothesize that life arises with high probability in complex chemical systems. Titan's methane and ammonia-water liquids are accessible to test this. Laboratory work is developing possible metabolisms and genetic systems in Titans.

  9. The Surface Composition of Titan

    NASA Astrophysics Data System (ADS)

    Clark, R. N.; Pearson, N.; Brown, R. H.; Cruikshank, D. P.; Barnes, J. W.; Jaumann, R.; Soderblom, L. A.; Griffith, C. A.; Rodriguez, S.; Le Mouelic, S.; Lunine, J.; Sotin, C.; Baines, K. H.; Buratti, B. J.; Nicholson, P. D.; Nelson, R.; Stephan, K.

    2011-12-01

    Determining the surface composition of Titan has been inhibited by the lack of spectral properties of potential compounds. We have measured the 0.35 to 5-micron spectral reflectance of a wide range of compounds that might be relevant to Titan and trends are now coming to light with possible spectral matches for classes of materials. While some compounds have been identified and mapped on Titan's surface, such as liquid ethane + methane lakes and benzene, the compounds responsible for the main spectral properties have remained elusive (Clark et al, JGR 2010). Titan's surface is seen in the near infrared in only a few spectral windows, near 0.94, 1.1, 1.3, 1.6, 2.0, 2.68-2.78, and 4.9-5.1 microns in the Cassini Visual and Infrared Mapping Spectrometer (VIMS) spectral range. At shorter wavelengths, UV absorption in the spectra of Titan's haze constrains the surface composition because haze particles settle onto Titan's surface. The average apparent reflectance in the IR windows generally decreases with increasing wavelength except for the 2.7 and 5-micron windows which are at similar levels. The decrease has led researchers to infer a number of compounds responsible for the observed decreasing spectral shape; the most common being water ice. But ice is incompatible with the 2.78/2.68 micron I/F ratio. Many organic compounds have absorptions that are not seen in spectra of Titan, eliminating them as possible major components at the surface, including many polycyclic aromatic hydrocarbons (PAH) previously thought to be compatible with parts of Titan's spectrum. We find that ring compounds similar to benzene rings, but with some C-H bonds replaced by NH have a closer match to Titan's overall spectrum and can explain the relative intensities observed in the spectral windows, including the 2.68 and 2.78-micron double window, the low 3-5 micron reflectance, and increased absorption near 2.1-microns. Key among these compounds that show general properties that match Titan are Cytosine (C4H5N3O), Uracil (C4H4N2O2), Guanine (C5H5N5O), and Adenine (C5H5N5). These compounds are the four nucleobases in the nucleic acid of RNA. If these compounds can be confirmed to be on Titan, their formation pathways may have implications for the formation of life. Other compounds that match features in Titan's spectra include the polycyclic aromatic hydrocarbon (PAH) coronene, consisting of 6 benzene rings. Coronene is also a naturally occurring mineral on Earth, known as karpatite. Combinations of coronene, phenanthene (C14H12), pentacene (C22H14), indole (C8H7N), Cytosine, Uracil, Guanine, and Adenine match the overall spectral structure of Titan spectra. Indole, Cytosine, and Uracil, have 1.5-micron bands that can explain the feature observed in DISR spectra of Titan's surface. These compounds can also help explain the pyrolysis results from the Huygens probe.

  10. The effect of phase transition on the failure behaviors of PZT 95/5 under shock compression

    NASA Astrophysics Data System (ADS)

    Zhang, Fuping; He, Hongliang; Liu, Gaomin; Liu, Yusheng

    2013-06-01

    PZT 95/5 ferroelectric ceramics has been utilized for the use in shock driven pulsed power supplies for many years. In previous studying, the low impendence failure layer had been confirmed in PZT 95/5 when the shock pressure is up to 2.4 GPa. But to the shock compression of the poled PZT 95/5, the failure behavior of this material is still unknown. In this paper, the failure behaviors of axially poled PZT 95/5 have been tested by measuring the particle velocity of the rear free surface at different pressures. Results show that the failure layer exists in poled PZT 95/5 when the shock pressure reaches 2.4 GPa. Through analysis the velocity profile of free surface, which shows that the velocity of failure layer is the same as the shock-wave speed and the delay time decreases with increasing the shock stress. Comparing the failure behaviors of unpoled PZT 95/5, it finds that the threshold pressure and the velocity of failure layer are the same, but the delay time in poled PZT 95/5 is slight higher than that in unpoled PZT 95/5. The FE to AFE phase transition has been suggested to explain the increase of the delay time in poled PZT 95/5.

  11. Role of zircon in tracing crustal growth and recycling

    NASA Technical Reports Server (NTRS)

    Compston, W.; Williams, I. S.; Armstrong, R. A.; Claoue-Long, J. C.; Kinny, P. D.; Foster, J. J.; Kroener, A.; Pidgeon, R. T.; Myers, J. S.

    1988-01-01

    Single crystal ion probe ages of zircons is discussed, which allow much better time resolution compared to other geochronological methods, although the technique is not without problems. Rocks from two areas that contain composite zircon populations, including true magmatic zircons as well as a variety of xenocrystic types are described. It is often difficult to distinguish these; xenocrystic zircons, for example, cannot always be identified on the basis of morphology alone. Additional evidence is needed before making age interpretations. Evidence is also presented of zircon growth long after the original time of crystallization, in some cases apparently at temperatures less than 300 C. The spectacular discovery of 4.1 to 4.2 Ga detrital zircons in metaquartzites from the Mount Narryer area of Western Australia is described. Similar zircons with ages as old as 4276 Ma have been found in the nearby Jack Hills area. The source areas or parent lithologies of these zircons have not yet been determined, but the author expects that they may be unrecognized or buried antecedents of the K rich Narryer gneisses. U or Th concentrations of zircon cannot be used to discriminate between felsic and mafic source rocks.

  12. Stability of zircon in dunite at 1400-1550°C

    NASA Astrophysics Data System (ADS)

    Anfilogov, V. N.; Krasnobaev, A. A.; Ryzhkov, V. M.; Kabanova, L. Ya.; Valizer, P. M.; Blinov, I. A.

    2015-09-01

    The results of experimental studies of interaction between zircon crystals and dunite at 1400-1550°C are given. At 1400°C no interaction of zircon with dunite takes place. At higher temperatures zircon interacts with olivine forming eutectoid mixture of baddeleyite and pyroxene grains. Change of free energy at interaction is close to zero and process is reversible. At 1550°C partial melting of dunite occurs, but character of interaction with dunite remains the same. Experiments results verify phase relationships in liquidus area at diagram. The obtained results allow explaining the ancient age of zircons in ultrabasite of folded areas.

  13. Mapping of Titan: Results from the first Titan radar passes

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.; Lunine, J. I.; Lopes, R.; Paganelli, F.; Lorenz, R. D.; Wood, C. A.; Kirk, R.; Wall, S.; Elachi, C.; Soderblom, L. A.; Ostro, S.; Janssen, M.; Radebaugh, J.; Wye, L.; Zebker, H.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W. T. K.; Kelleher, K.; Muhleman, D.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Stiles, B.; Vetrella, S.; West, R.

    2006-12-01

    The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes and two large impact craters. We interpret the brightness variations in much of the swaths to result from roughness variations caused by fracturing and erosion of Titan's icy surface, with additional contributions from a combination of volume scattering and compositional variations. Despite the small amount of Titan mapped to date, the significant differences between the terrains of the two swaths suggest that Titan is geologically complex. The overall scarcity of impact craters provides evidence that the surface imaged to date is relatively young, with resurfacing by cryovolcanism, fluvial erosion, aeolian erosion, and likely atmospheric deposition of materials. Future radar swaths will help to further define the nature of and extent to which internal and external processes have shaped Titan's surface.

  14. Mapping of Titan: Results from the first Titan radar passes

    USGS Publications Warehouse

    Stofan, E.R.; Lunine, J.I.; Lopes, R.; Paganelli, F.; Lorenz, R.D.; Wood, C.A.; Kirk, R.; Wall, S.; Elachi, C.; Soderblom, L.A.; Ostro, S.; Janssen, M.; Radebaugh, J.; Wye, L.; Zebker, H.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Stiles, B.; Vetrella, S.; West, R.

    2006-01-01

    The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes and two large impact craters. We interpret the brightness variations in much of the swaths to result from roughness variations caused by fracturing and erosion of Titan's icy surface, with additional contributions from a combination of volume scattering and compositional variations. Despite the small amount of Titan mapped to date, the significant differences between the terrains of the two swaths suggest that Titan is geologically complex. The overall scarcity of impact craters provides evidence that the surface imaged to date is relatively young, with resurfacing by cryovolcanism, fluvial erosion, aeolian erosion, and likely atmospheric deposition of materials. Future radar swaths will help to further define the nature of and extent to which internal and external processes have shaped Titan's surface. ?? 2006 Elsevier Inc. All rights reserved.

  15. Radioactivity in zircon and building tiles.

    PubMed

    Deng, W; Tian, K; Zhang, Y; Chen, D

    1997-08-01

    Zircon (ZrSiO4) is commonly used in the manufacture of glazed tiles. In this study we found high concentrations of the radionuclides 226Ra, 232Th, 40K in zircon sand. The average radium equivalent (A(Ra) + 1.26 A(Th) + 0.086 A(k)) in zircon sand is 17,500 Bq kg(-1), which is 106 times as much as that in ordinary building materials. The external radiation (gamma + beta) dose rates in air at 5 cm from the surface of piles of zircon sand sacks range from 1.1 to 4.9 x 10(-2) mGy h(-1) with an average of 2.1 x 10(-2) mGy h(-1). Although no elevated gamma-ray radiation or radon exhalation rate was detected in rooms decorated with glazed tiles, which is characteristic of combined alpha, beta and gamma emitting thin materials, the average gamma-ray radiation dose rate at the surface of the tile stacks in shops is 1.5 times as much as the indoor background level. The average area density of total beta emitting radionuclides in glazed floor tiles and glazed wall tiles is 0.30 Bq cm(-2) and 0.28 Bq cm(-2), respectively. It was estimated that the average beta dose rates in tissue at a depth 7 mg cm(-2) with a distance 20-100 cm from the floor tiles were 3.2 to 0.9 x 10(-7) Gy h(-1). The study indicates that the beta-rays from glazed tiles might be one of the main factors leading to an increase in ionizing radiation received by the general public. Workers in glazed tile manufacturing factories and in tile shops or stores may be exposed to elevated levels of both beta-rays and gamma-rays from zircon sand or glazed tile stacks. No elevated radiation from unglazed tiles was detected. PMID:9228172

  16. Titan's Spectacular Volte-Face

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.

    2013-10-01

    Like Earth, Titan sports lakes, storms and rainfall. These features derive from a methane cycle, reminiscent of Earth's hydrological cycle; methane exists as an ice, liquid and gas and transfers between the surface and atmosphere, according to the seasonal weather. Titan's seasons contrast Earth’s. Imagine a summer trip to 70 latitude, where hurricane-sized storms burst forth out of a clear sky every few months for about 15 years. Then they vanish for another 15 years. Envision a trip to the winter polar region. Here the sky is perhaps clear except that the high haze, which filters sunlight like a translucent globe, is somewhat thicker than it is in the summer. Imperceptibly, you are blocking the diffuse organic matter, which is slowly settling out of the hazy orb, and accumulating on the polar surface. These effects are a few of the many that derive from Titan’s circulation and its seasonal changes during the satellite's 29.5 Earth year orbit about the Sun. In particular, and as indicated in recent observations, Titan's circulation flip-flopped. Before equinox in 2009, on average, air rose in the southern polar region and downwelled in the northern polar region. Now the reverse appears to be happening. Here we discuss the observations ranging from the surface to ~500 km altitude that reveal the symphony of responses of Titan's surface and atmosphere to this dramatic shift. In addition we discuss the syntheses of these effects, from theoretical efforts involving microphysical models, local cloud models and general circulation models, with the question of why Titan's seasonal changes are so much more spectacular compared to those of Earth.

  17. Annealing effects on cathodoluminescence of zircon

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Y.; Nishido, H.; Noumi, Y.

    2011-12-01

    U-Pb zircon dating (e. g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) imaging allows us to recognize internal zones and domains with different chemical compositions and structural disorder at high spatial resolution. The CL of zircon is attributed by various types of emission centers, which are extrinsic ones such as REE impurities and intrinsic ones such as structural defects. Metamictization resulted from radiation damage to the lattice by alpha particles from the decay of U and Th mostly causes an effect on the CL features of zircon as a defect center. However, slightly radiation-damaged zircon, which is almost nondetectable by XRD, has not been characterized using CL method. In this study, annealing effects on CL of zircon has been investigated to clarify a recovery process of the damaged lattice at low radiation dose. A single crystal of zircon from Malawi was selected for CL measurements. It contains HfO2: 2.30 w.t %, U: 241 ppm and Th: 177 ppm. Two plate samples perpendicular to c and a axes were prepared for annealing experiments during 12 hours from room temperature to 1400 degree C. Color CL images were captured using a cold-cathode microscope (Luminoscope: Nuclide ELM-3R). CL spectral measurements were conducted using an SEM (JEOL: JSM-5410) combined with a grating monochromator (Oxford: Mono CL2) to measure CL spectra ranging from 300 to 800 nm in 1 nm steps with a temperature controlled stage. The dispersed CL was collected by a photoncounting method using a photomultiplier tube (Hamamatsu: R2228) and converted to digital data. All CL spectra were corrected for the total instrumental response. Spectral analysis reveals an anisotropy of the CL emission bands related to intrinsic defect center in blue region, radiation-induced defect center from 500 to 700 nm, and trivalent Dy impurity center at 480 and 580 nm, but their relative intensities are almost constant. CL on the surface perpendicular to c-axis, at which direction its intensity is maximum, was characterized in this study. Color CL imaging indicates yellow emission below 300 degree C, white to pale blue between 400 ~ 800 degree C and blue above 900 degree C. The broad band emission assigned to radiation-induced defect center in metamict state decreases in an increase of annealed temperature and disappeared above 700 degree C, whereas any change in XRD patterns was not detected. The blue CL emission caused by intrinsic defect center gradually increases in heating due to a recovery of its crystal field. Furthermore, the emission bands of trace amounts of trivalent Gd at 320 nm and Er at 400nm become to be appeared in response to a recrystallization by annealing. Therefore, CL analysis provides useful information on characteristics of the nature of metamict zircon rather than other conventional methods.

  18. Effects of thickness on the piezoelectric and dielectric properties of lead zirconate titanate thin films

    E-print Network

    Sottos, Nancy R.

    orientation were measured by a laser Doppler heterodyne interferometer. The weak-field dielectric constants Ferroelectric ceramics have been employed extensively in a variety of sensors and actuators including strain gauges, pressure transducers, and accelerometers. Bulk ferroelectric ceramic sensors have certain

  19. Nonaqueous solution synthesis process for preparing oxide powders of lead zirconate titanate and related materials

    DOEpatents

    Voigt, James A. (Corrales, NM); Sipola, Diana L. (Albuquerque, NM); Tuttle, Bruce A. (Albuquerque, NM); Anderson, Mark T. (Woodbury, MN)

    1999-01-01

    A process for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This process provides fine perovskite-phase powders with ferroelectric properties which are particularly useful in a variety of electronic applications.

  20. Microstructural evolution and macroscopic property relationship in antiferroelectric lead lanthanum stannate zirconate titanate ceramics

    NASA Astrophysics Data System (ADS)

    Chan, Wai-Hung; Xu, Z.; Zhang, Yong; Hung, T. F.; Chen, Haydn

    2003-10-01

    The antiferroelectric (AFE) Pb0.97La0.02(Zr0.60Sn0.30Ti0.10)O3 ceramic has a composition near the morphotropic phase boundary that separates the AFE from the ferroelectric (FE) phase. Its structural changes as well as macroscopic properties were investigated over a temperature range of -180-300 °C using transmission electron microscopy, dielectric spectroscopy, and Sawyer-Tower polarization measurements. The previously reported tetragonal AFE phase is shown to be an incommensurate orthorhombic phase and it exhibits a sequence of phase transformations on heating from the incommensurate AFE to a multicell cubic, then to a simple cubic phase. This microstructural evolution with temperature is consistent with the corresponding macroscopic dielectric and AFE behaviors. The temperature dependence of the AFE-FE switching field is closely associated with the corresponding temperature dependence of the incommensurate modulation wavelength.

  1. High-resolution x-ray diffraction study of single crystals of lead zirconate titanate

    NASA Astrophysics Data System (ADS)

    Gorfman, S.; Keeble, D. S.; Glazer, A. M.; Long, X.; Xie, Y.; Ye, Z.-G.; Collins, S.; Thomas, P. A.

    2011-07-01

    The symmetry of single-crystal piezoelectric PbZr1-xTixO3, with x?0.31 and x?0.46, has been investigated by high-resolution x-ray diffraction, both at room temperature and up to and above the Curie temperature. Reciprocal space maps around a selection of Bragg reflections were collected and self-consistent patterns showing Bragg splittings were observed. The analysis of the separation of peaks from different twin domains provides precise information on PbZr1-xTixO3 symmetry when approaching the morphotropic phase boundary at x=0.48 from the zirconium-rich side.

  2. Single Crystal Study of Competing Rhombohedral and Monoclinic Order in Lead Zirconate Titanate

    NASA Astrophysics Data System (ADS)

    Phelan, D.; Long, X.; Xie, Y.; Ye, Z.-G.; Glazer, A. M.; Yokota, H.; Thomas, P. A.; Gehring, P. M.

    2010-11-01

    Neutron diffraction data obtained on single crystals of PbZr1-xTixO3 with x=0.325 and x=0.460, which lie on the pseudorhombohedral side of the morphotropic phase boundary, suggest a coexistence of rhombohedral (R3m/R3c) and monoclinic (Cm) domains and that monoclinic order is enhanced by Ti substitution. A monoclinic phase with a doubled unit cell (Cc) is ruled out as the ground state.

  3. Nonaqueous solution synthesis process for preparing oxide powders of lead zirconate titanate and related materials

    DOEpatents

    Voigt, J.A.; Sipola, D.L.; Tuttle, B.A.; Anderson, M.T.

    1999-06-01

    A process is disclosed for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This process provides fine perovskite-phase powders with ferroelectric properties which are particularly useful in a variety of electronic applications. 4 figs.

  4. Fabrication and characterization of the multiferroic birelaxor lead-iron-tungstate/lead-zirconate-titanate

    NASA Astrophysics Data System (ADS)

    Kumar, Ashok; Katiyar, R. S.; Scott, J. F.

    2010-09-01

    We compare chemical solution deposition (CSD) and pulsed laser deposition (PLD), specimens of the room temperature, single-phase, multiferroic magnetoelectric, [PbFe0.67W0.33O3]x[PbZr0.53Ti0.47O3]1-x (PZTFWx˜0.40

  5. Polar nanodomains and local ferroelectric phenomena in relaxor lead lanthanum zirconate titanate ceramics

    SciTech Connect

    Shvartsman, V.V.; Kholkin, A.L.; Orlova, A.; Kiselev, D.; Bogomolov, A.A.; Sternberg, A.

    2005-05-16

    Transparent Pb{sub 0.9125}La{sub 0.0975}(Zr{sub 0.65}Ti{sub 0.35}){sub 0.976}O{sub 3} ceramics (conventionally abbreviated as PLZT 9.75/65/35) is a typical relaxor characterized by the absence of the ferroelectric order at the macroscopic scale. In this letter, we report on the observation of complex polar structures on the surface of this material via piezoresponse force microscopy (PFM). The irregular polarization patterns are associated with the formation of a glassy state, where random electric fields destroy the long-range ferroelectric order. The measure of the disorder, the correlation length of {approx}50 nm, was directly deduced from the PFM images. Local poling of relaxor ceramics resulted in the formation of a stable micron-size domain that could be continuously switched under varying dc bias (local relaxor-ferroelectric phase transition). Fractal analysis was applied to analyze the origin of local order in PLZT.

  6. Characterization of lead zirconate titanate piezoceramic using high frequency ultrasonic spectroscopy

    E-print Network

    Cao, Wenwu

    . The Kramers­Kronig relation between ultrasonic phase velocity and attenuation was compared to measured results were also used to verify the Kramers­Kronig relations.2 The ultrasonic spectroscopy method has been predicted by the Kramers­Kronig rela- tions. II. THE REFLECTION AND REFRACTION OF A LONGITUDINAL WAVE

  7. Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator.

    PubMed

    Luo, Chuan; Omelchenko, Irina; Manson, Robert; Robbins, Carol; Oesterle, Elizabeth C; Cao, Guo Zhong; Shen, I Y; Hume, Clifford R

    2015-01-01

    Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800?µm by 800?µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24?kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays. PMID:26631107

  8. Design of a distributive load sensor using PZT

    NASA Astrophysics Data System (ADS)

    Georgiades, G.; Oyadiji, S. O.; Liu, Z.

    2005-05-01

    The work presented relates to the design and construction of an inexpensive distributive load sensor. It is to be used for impact tests on samples which are in the form of flexible or deformable beams of a considerable length. The sensor compromises of forty fingers made of steel, arranged next to each other and covering a total length of about a meter. Both ends of each finger are clamped. PZT ceramic patches, which are bonded to the bottom surfaces of each finger, are used to convert the impact response into an electrical signal. An amplifier and filter were designed for each finger. The frequency range over which each finger operates is extended by the use of a Butterworth filter. An amplifier box was built containing the charge amplifier circuitry and filter of each of the forty fingers comprising the distributive sensor. Tests are performed on the distributive sensor in order to show that this simple and inexpensive distributive sensor is effective. The results are presented and discussed.

  9. Measurement and calculation of PZT thin film longitudinal piezoelectric coefficients.

    SciTech Connect

    Christman, J. A.; Kim, S.-H.; Kingon, A. I.; Maiwa, H.; Maria, J.-P.; Streiffer, S. K.

    1999-04-26

    The ferroelectric and piezoelectric properties of 2000 {angstrom} thick chemical solution deposited Pb(Zr{sub x}Ti{sub 1{minus}x})O{sub 3} (PZT) thin films were investigated. Several Zr/Ti ratios were studied: 30/70, 50/50 and 65/35, which correspond to tetragonal, near-morphotropic, and rhombohedral symmetries. In all samples, a {l_brace}111{r_brace}-texture is predominant. Longitudinal piezoelectric coefficients and their dc field dependence were measured using the contact AFM method. The expected trend of a maximum piezoelectric coefficient at or near to the MPB was not observed. The composition dependence was small, with the maximum d{sub 33} occurring in the tetragonal material. To explain the results, crystallographic texture and film thickness effects are suggested. Using a modified phenomenological approach, derived electrostrictive coefficients, and experimental data, d{sub 33} values were calculated. Qualitative agreement was observed between the measured and calculated coefficients. Justifications of modifications to the calculations are discussed.

  10. Organic chemistry on Titan: Surface interactions

    NASA Technical Reports Server (NTRS)

    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.

  11. Dynamics of Titan's thermosphere H. Rishbetha, b,

    E-print Network

    Yelle, Roger V.

    Dynamics of Titan's thermosphere H. Rishbetha, b, *, R.V. Yellea , M. Mendilloa a Center for Space; accepted 23 June 1999 Abstract We estimate the wind speeds in Titan's thermosphere by considering, but in Titan's thermosphere they are mainly controlled by the nonlinear advection and curvature forces

  12. 29 August 2011 2011 TECH TITAN

    E-print Network

    Chiao, Jung-Chih

    29 August 2011 2011 TECH TITAN Media Contact: Herb Booth, Office:817-272-7075, Cell:214 electrical engineering professor, a 2011 Tech Titan in the Technology Innovator category. The council has. The Tech Titans awards are in their 11 year of recognizing outstanding technology companies and North Texas

  13. Congratulations to the 2011 Tech Titan Recipients

    E-print Network

    Chiao, Jung-Chih

    Congratulations to the 2011 Tech Titan Recipients Published Tuesday, September 13, 2011 6:00 am Eleven new Tech Titans were crowned and $11,000 was pledged for the MTBC STEM Partnership Fund at his year's annual Tech Titans Gala, held Friday, August 26 at the Hilton Anatole Hotel near downtown Dallas

  14. Sputtering and heating of Titan's upper atmosphere

    E-print Network

    Johnson, Robert E.

    Sputtering and heating of Titan's upper atmosphere BY ROBERT E. JOHNSON 1,2,* 1 University, USA Titan is an important endpoint for understanding atmospheric evolution. Prior to Cassini's arrival ) and dominated by atmospheric sputtering. Recent analysis of the structure of Titan's thermosphere and corona

  15. Volume 108, number 1 CHI:M!C-AL PfiYSICS LETTERS 13 July 1984 FREQUENCY-DOMAIN PHOTOPYROELECTRIC SPECTROSCOPY OF CONDENSED PHASES (PPES)

    E-print Network

    Mandelis, Andreas

    ~~l~~~onestpiemefcctric transducers are usually made out of piezoetectric ceramic (e.g. lead zirconate titanate, PZT [l---3]). These ceramics es- hibit a ~nuch higher frequency response than micro- phone transducers, and thus they became dominant in photoacoustic applications where fast transducer response is required, such 3s pulsed laser PAS

  16. Processing of Fine-Scale Piezoelectric Ceramic/Polymer Composites for Sensors and Actuators

    NASA Technical Reports Server (NTRS)

    Janas, V. F.; Safari, A.

    1996-01-01

    The objective of the research effort at Rutgers is the development of lead zirconate titanate (PZT) ceramic/polymer composites with different designs for transducer applications including hydrophones, biomedical imaging, non-destructive testing, and air imaging. In this review, methods for processing both large area and multifunctional ceramic/polymer composites for acoustic transducers were discussed.

  17. Nonlinear properties of lead zirconatetitanate piezoceramics Wenhua Jiang

    E-print Network

    Cao, Wenwu

    temperature to temperatures above the Curie temperature. Our present work is devoted to study the nonlinear as their temperature dependence for modi- fied lead zirconate­titanate ceramics type Piezolan S2 , L, Tm , by means St. Hopkinton, MA 01748 , and high density PZT-5H HD Motorola at room temperature. By means

  18. doi:10.1016/S0301-5629(03)00953-0 Original Contribution

    E-print Network

    Konofagou, Elisa E.

    the localized oscillatory motion resulting from the harmonic radiation force produced by two focused ultrasound-element focused transducers and one lead zirconate-titanate (PZT) composite 16-element probe. Four agar gels were induced displacement was used. In experiments with gels of different stiffness, the resulting amplitude

  19. Effects of exchange interactions on magnetoacoustic resonance in layered nanocomposites of yttrium iron garnet

    E-print Network

    Srinivasan, Gopalan

    Effects of exchange interactions on magnetoacoustic resonance in layered nanocomposites of yttrium coefficient at MAR, about 75­100 V/cm Oe for yttrium­iron garnet (YIG)/lead zirconate­titanate (PZT) nano. Studies were performed on bilayers of yttrium iron garnet (YIG) films and (001) lead magnesium niobate

  20. IEEE TransacTIons on UlTrasonIcs, FErroElEcTrIcs, and FrEqUEncy conTrol, vol. 59, no. 5, May 2012 1043 08853010/$25.00 2012 IEEE

    E-print Network

    Afshari, Ehsan

    zirconate titanate (PZT) thin film on silicon RF micro electro-mechanical system (MEMS) plate, beam, ring coupling [1], [2]. However, the re- liance on film thickness to set frequency in the thickness- mode vibrations of FBars poses significant challenges to achieving compact integration of multiple frequencies

  1. Probing Titan's Atmosphere with ALMA

    NASA Astrophysics Data System (ADS)

    Serigano, J., IV; Nixon, C. A.; Cordiner, M. A.; Charnley, S. B.; Teanby, N. A.; Palmer, M.; Milam, S.; Villanueva, G. L.; Paganini, L.; Mumma, M. J.; Achterberg, R. K.; Kuan, Y. J.; Kisiel, Z.

    2014-12-01

    The advent of the Atacama Large Millimeter/Sub-millimeter 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. Previously, observatories such as the Sub Millimeter Array (SMA) and IRAM (30-m and Plateau de Bure Interferometer) have demonstrated the detection of molecules such as CO, HCN, HC3N and CH3CN in Titan's atmosphere, allowing the determination of vertical abundance gradients, and isotopic ratios of 13C/12C, 15N/14N and 18O/16O. More recently, the Herschel observatory made the first detection of hydrogen isocyanide (HNC) in Titan's atmosphere. However, to date all these observations have not resolved Titan's disk, and measured only disk-averaged abundances. ALMA changes this picture dramatically, since the full ALMA will eventually achieve a resolution of 0.004" at the shortest wavelengths, compared to Titan's angular size of 0.800". We will discuss early Titan science using ALMA, including the re-observation of species seen previously by SMA, IRAM and Herschel, and the search for new species and isotopes. We will also show the capability of ALMA to spatially map the emissions of stronger molecular species, and measure winds by using resolved spectral line profiles.

  2. Testing the reliability of information extracted from ancient zircon

    NASA Astrophysics Data System (ADS)

    Kielman, Ross; Whitehouse, Martin; Nemchin, Alexander

    2015-04-01

    Studies combining zircon U-Pb chronology, trace element distribution as well as O and Hf isotope systematics are a powerful way to gain understanding of the processes shaping Earth's evolution, especially in detrital populations where constraints from the original host are missing. Such studies of the Hadean detrital zircon population abundant in sedimentary rocks in Western Australia have involved analysis of an unusually large number of individual grains, but also highlighted potential problems with the approach, only apparent when multiple analyses are obtained from individual grains. A common feature of the Hadean as well as many early Archaean zircon populations is their apparent inhomogeneity, which reduces confidence in conclusions based on studies combining chemistry and isotopic characteristics of zircon. In order to test the reliability of information extracted from early Earth zircon, we report results from one of the first in-depth multi-method study of zircon from a relatively simple early Archean magmatic rock, used as an analogue to ancient detrital zircon. The approach involves making multiple SIMS analyses in individual grains in order to be comparable to the most advanced studies of detrital zircon populations. The investigated sample is a relatively undeformed, non-migmatitic ca. 3.8 Ga tonalite collected a few kms south of the Isua Greenstone Belt, southwest Greenland. Extracted zircon grains can be combined into three different groups based on the behavior of their U-Pb systems: (i) grains that show internally consistent and concordant ages and define an average age of 3805±15 Ma, taken to be the age of the rock, (ii) grains that are distributed close to the concordia line, but with significant variability between multiple analyses, suggesting an ancient Pb loss and (iii) grains that have multiple analyses distributed along a discordia pointing towards a zero intercept, indicating geologically recent Pb-loss. This overall behavior has important implications for the studies of detrital populations, suggesting that even zircon from a supposedly single population can form a complex age distribution pattern. Notably, the age groups are also very similar to those identified at this time interval in the zircon population from Jack Hills in Western Australia. Interestingly ?18O in zircon from the Greenland tonalite sample is very consistent at the mantle value and independent of the behavior of the U-Pb system, suggesting general stability of even metamict zircon as related to the O isotope exchange. At least it indicates that if this exchange takes place as it appears to be the case for the Hadean zircon, factors other than just the radiation damage have to play a role in the zircon modification.

  3. Large Particle Titanate Sorbents

    SciTech Connect

    Taylor-Pashow, K.

    2015-10-08

    This research project was aimed at developing a synthesis technique for producing large particle size monosodium titanate (MST) to benefit high level waste (HLW) processing at the Savannah River Site (SRS). Two applications were targeted, first increasing the size of the powdered MST used in batch contact processing to improve the filtration performance of the material, and second preparing a form of MST suitable for deployment in a column configuration. Increasing the particle size should lead to improvements in filtration flux, and decreased frequency of filter cleaning leading to improved throughput. Deployment of MST in a column configuration would allow for movement from a batch process to a more continuous process. Modifications to the typical MST synthesis led to an increase in the average particle size. Filtration testing on dead-end filters showed improved filtration rates with the larger particle material; however, no improvement in filtration rate was realized on a crossflow filter. In order to produce materials suitable for column deployment several approaches were examined. First, attempts were made to coat zirconium oxide microspheres (196 µm) with a layer of MST. This proved largely unsuccessful. An alternate approach was then taken synthesizing a porous monolith of MST which could be used as a column. Several parameters were tested, and conditions were found that were able to produce a continuous structure versus an agglomeration of particles. This monolith material showed Sr uptake comparable to that of previously evaluated samples of engineered MST in batch contact testing.

  4. Structure of Titan's evaporites

    E-print Network

    Cordier, D; Barnes, J W; MacKenzie, S M; Bahers, T Le; Nna-Mvondo, D; Rannou, P; Ferreira, A G

    2015-01-01

    Numerous geological features that could be evaporitic in origin have been identified on the surface of Titan. Although they seem to be water-ice poor, their main properties -chemical composition, thickness, stratification- are essentially unknown. In this paper, which follows on a previous one focusing on the surface composition (Cordier et al., 2013), we provide some answers to these questions derived from a new model. This model, based on the up-to-date thermodynamic theory known as "PC-SAFT", has been validated with available laboratory measurements and specifically developed for our purpose. 1-D models confirm the possibility of an acetylene and/or butane enriched central layer of evaporitic deposit. The estimated thickness of this acetylene-butane layer could explain the strong RADAR brightness of the evaporites. The 2-D computations indicate an accumulation of poorly soluble species at the deposit's margin. Among these species, HCN or aerosols similar to tholins could play a dominant role. Our model pre...

  5. PMN-PT–PZT composite films for high frequency ultrasonic transducer applications

    PubMed Central

    Hsu, Hsiu-Sheng; Benjauthrit, Vatcharee; Zheng, Fan; Chen, Rumin; Huang, Yuhong; Zhou, Qifa; Shung, K. Kirk

    2013-01-01

    We have successfully fabricated x(0.65PMN-0.35PT)–(1 ? x)PZT (xPMN-PT–(1 ? x)PZT), where x is 0.1, 0.3, 0.5, 0.7 and 0.9, thick films with a thickness of approximately 9 µm on platinized silicon substrate by employing a composite sol–gel technique. X-ray diffraction analysis and scanning electron microscopy revealed that these films are dense and creak-free with well-crystallized perovskite phase in the whole composition range. The dielectric constant can be controllably adjusted by using different compositions. Higher PZT content of xPMN-PT–(1 ? x)PZT films show better ferroelectric properties. A representative 0.9PMN-PT–0.1PZT thick film transducer is built. It has 200 MHz center frequency with a ?6 dB bandwidth of 38% (76 MHz). The measured two-way insertion loss is 65 dB. PMID:23750072

  6. Low-temperature processing of PZT thin films by 2.45 GHz microwave heating

    NASA Astrophysics Data System (ADS)

    Wang, Z. J.; Otsuka, Y.; Cao, Z.; Zhu, M. W.; Yoshikawa, N.; Kokawa, H.

    2008-12-01

    The effect of microwave heating with a frequency of 2.45 GHz on the low-temperature crystallization of Pb(ZrxTi1-x)O3 (PZT) films was investigated. PZT thin films were coated on Pt/Ti/SiO2/Si substrates by the sol-gel method and then crystallized by single-mode 2.45 GHz microwave irradiation in the magnetic field. The elevated temperature generated by microwave heating used to obtain the perovskite phase was only 450°C, which is significantly lower than that of conventional thermal processing. The PZT films crystallized by microwave heating at 450°C showed similar ferroelectric properties to those of the films crystallized by conventional thermal processing at 600°C. The average remanent polarization and coercive field of the PZT films are approximately 21 µC/cm2 and 90 kV/cm, respectively. It is clear that single-mode microwave irradiation in the magnetic field is effective for obtaining perovskite PZT thin films at low temperatures.

  7. Charged particles in Titan's ionosphere

    NASA Astrophysics Data System (ADS)

    Tripathi, Sachchida

    2010-05-01

    Charged particles in Titan's ionosphere Marykutty Michael1, Sachchida Nand Tripathi1,2,3, Pratima Arya1 1Indian Institute of Technology Kanpur 2Oak Ridge Associated Universities 3NASA Goddard Space Flight Center Observations by two instruments onboard the Cassini spacecraft, Ion Neutral Mass Spectrometer (INMS) and CAssini Plasma Spectrometer (CAPS), revealed the existence of heavy hydrocarbon and nitrile species with masses of several thousand atomic mass units at altitudes of 950 - 1400 km in the atmosphere of Titan (Waite et al., 2007; Crary et al., 2009). Though these particles were believed to be molecules, they are most likely aerosols formed by the clumping of smaller molecules (Waite et al., 2009). These particles were estimated to have a density of 10-3 kg m-3 and a size of up to 256 nm. The existence of very heavy ions has also been observed by the CAPS components with a mass by charge ratio of up to 10000 (Coates et al., 2007, 2009; Sittler et al., 2009). The goal of this paper is to find out whether the so called heavy ions (or charged particles) are generated by the charge transfer of ions and electrons to the particles. The charging of these particles has been studied by using the charge balance equations that include positive ions, negative ions, electrons, neutral and charged particles. Information on the most abundant ion clusters are obtained from Vuitton et al., (2009) and Wilson and Atreya, (2004). Mass by charge ratio thus calculated will be compared with those observed by Coates et al. (2007). References: Coates AJ, et al., Discovery of heavy negative ions in Titan's ionosphere, Geophys. Res. Lett., 34:L22103, 2007. Coates AJ, et al., Heavy negative ions in titan's ionosphere: altitude and latitude dependence. Planet. Space Sci., doi:10.1016/j.pss.2009.05.009, 2009. Crary F.J., et al., Heavy ions, temperatures and winds in titan's ionosphere: Combined cassini caps and inms observations. Planet. Space Sci., doi:10.1016/j.pss.2009.09.006, 2009. Sittler,E.C. et al., Heavy ion formation in Titan's ionosphere: Magnetospheric introduction of free oxygen and a source of Titan's aerosols? Planet. Space Sci., doi:10.1016/j.pss.2009.07.017, 2009. Vuitton, V., Negative ion chemistry in Titan's upper atmosphere, Planet. Space Sci., doi:10.1016/j.pss.2009.04.004, 2009. Waite J.H, et al., The process of tholin formation in Titan's upper atmosphere. Science, doi: 10.1126/science.1139727, 316, 870, 2007. Waite JH, et al., High altitude production of Titan's aerosols, In Titan from Cassini-Huygens, edited by RH. Brown, J.P Lebreton, JH Waite, Springer, 2009. Wilson, E.H. and S. Atreya, Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere, J. Geophys. Res., 109, E06002, doi:10.1029/2003JE002181, 2004.

  8. Preparation of Lead Zirconate by Homogeneous Precipitation and Calcination

    E-print Network

    Tas, A. Cuneyt

    Preparation of Lead Zirconate by Homogeneous Precipitation and Calcination Ersin Emre Oren, Ercan. Introduction LEAD ZIRCONATE (PbZrO3) is an antiferroelectric ceramic with a Curie temperature of 230°C electric field to the ceramic in the antifer- roelectric state) leads to significant energy storage

  9. Experimental calibration of oxygen isotope fractionation between quartz and zircon

    E-print Network

    Bindeman, Ilya N.

    Experimental calibration of oxygen isotope fractionation between quartz and zircon Dustin Trail a the results of an experimental calibration of oxygen isotope fractionation between quartz and zircon. Data was buffered at the fayalite­magne- tite­quartz equilibrium. Oxygen isotope fractionation shows no clear

  10. Will Titan lose its veil?

    NASA Astrophysics Data System (ADS)

    Dimitrov, V.

    2007-08-01

    Methane CH4 is the only highly reactive and short-lived background component in Titan's atmosphere, so its overall reserve predetermines both features and duration of atmospheric chemical activity. Titan's global chemical activity is considered in terms of methane cycle. One cycle is defined as a period T0=7.0.1014s of complete photochemical destruction of methane's observable atmospheric content CH04 = 2.33.1017 kg. Cycle duration T0, number of the past NP =200±20, future NF =500±50 and total Nmax=NP+NF =700±70 cycles are the main quantitative indices of the global chemical activity [2]. The fact that the period T0 is much less than Titan's lifetime TT =1.42*1017s implies that the current content CH04 is continuously replenishing by methane global circulation. There are two sources of this replenishment, i.e. the outgassing of primordial methane reserve trapped in Titan's interior as the clathrate, and the (sub)ground liquidphase reduction of non-saturated final products of the atmospheric photochemical process. Internal reserve provides the dominant portion (>95%) of general recycling, while reducing reconversion is the minor constituent of the global balance. Yet, there is the problem of the availability of the off-the-shelf trapped methane. Overall admissible stock of the trapped methane depends on its internal allocation and falls in the range (CH4)max1,2=(15.3÷33.3).1020 kg, while continuous atmospheric activity during the whole Titan's life TSun 5.0.1017s needs only (CH4)crit=(CH04 ).Nmax = .(CH4)max 1.65.1020 kg. In turn, this bulk (CH4)crit depends on the clathrate cage-filling efficiency (molecular packing index) {kg CH4/kg clathrate} and can be provided if equals respectively to [1] crit1= (TSun/T0).[(CH4)0/[(CH4)max1] = 5.45.10-3 crit2= (TSun/T0).[(CH4)0/[(CH4)max2] = 2.51.10-3 Thus, the interrelation of overall trapped stock (CH4)max and crucial -values assigns the critical value (CH4)crit that in turn predetermines the very fate of Titan's veil. If the real stock (CH4)real (CH4)crit=1.65.1020 kg, than Titan will lose its veil inevitably (scenario of the "mosaic history"), otherwise (CH4)real (CH4)crit the veil survives down to Titan's dying day ("continuous history"). References [1] H. B. Niemann and 17-co-authors, Nature, 438, 779, (2005). [2] V. Dimitrov, Prog. React. Kin. Mech. 30, N4, 227, (2006).

  11. 932 IEEE TRANSACTIONS ON MAGNETICS, VOL. 39, NO. 2, MARCH 2003 Vibration Control of a PZT Actuated Suspension

    E-print Network

    Horowitz, Roberto

    932 IEEE TRANSACTIONS ON MAGNETICS, VOL. 39, NO. 2, MARCH 2003 Vibration Control of a PZT Actuated Suspension Dual-Stage Servo System Using a PZT Sensor Yunfeng Li, Roberto Horowitz, and Robert Evans Abstract--Structural resonance modes of the head stack and suspension assembly are one of the major limiting factors

  12. A Flexible Ultrasound Transducer Array with Micro-Machined Bulk PZT

    PubMed Central

    Wang, Zhe; Xue, Qing-Tang; Chen, Yuan-Quan; Shu, Yi; Tian, He; Yang, Yi; Xie, Dan; Luo, Jian-Wen; Ren, Tian-Ling

    2015-01-01

    This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications. PMID:25625905

  13. An optimized strain demodulation method for PZT driven fiber Fabry-Perot tunable filter

    NASA Astrophysics Data System (ADS)

    Sheng, Wenjuan; Peng, G. D.; Liu, Yang; Yang, Ning

    2015-08-01

    An optimized strain-demodulation-method based on piezo-electrical transducer (PZT) driven fiber Fabry-Perot (FFP) filter is proposed and experimentally demonstrated. Using a parallel processing mode to drive the PZT continuously, the hysteresis effect is eliminated, and the system demodulation rate is increased. Furthermore, an AC-DC compensation method is developed to address the intrinsic nonlinear relationship between the displacement and voltage of PZT. The experimental results show that the actual demodulation rate is improved from 15 Hz to 30 Hz, the random error of the strain measurement is decreased by 95%, and the deviation between the test values after compensation and the theoretical values is less than 1 pm/??.

  14. Temperature field analysis for PZT pyroelectric cells for thermal energy harvesting.

    PubMed

    Hsiao, Chun-Ching; Ciou, Jing-Chih; Siao, An-Shen; Lee, Chi-Yuan

    2011-01-01

    This paper proposes the idea of etching PZT to improve the temperature variation rate of a thicker PZT sheet in order to enhance the energy conversion efficiency when used as pyroelectric cells. A partially covered electrode was proven to display a higher output response than a fully covered electrode did. A mesh top electrode monitored the temperature variation rate and the electrode area. The mesh electrode width affected the distribution of the temperature variation rate in a thinner pyroelectric material. However, a pyroelectric cell with a thicker pyroelectric material was beneficial in generating electricity pyroelectrically. The PZT sheet was further etched to produce deeper cavities and a smaller electrode width to induce lateral temperature gradients on the sidewalls of cavities under homogeneous heat irradiation, enhancing the temperature variation rate. PMID:22346652

  15. THE MONOCLINIC PHASE IN PZT: NEW LIGHT ON MORPHOTROPIC PHASE BOUNDARIES

    SciTech Connect

    NOHEDA,B.; GONZALO,J.A.; GUO,R.; PARK,S.E.; CROSS,L.E.; COX,D.E.; SHIRANE,G.

    2000-03-09

    A summary of the work recently carried out on the morphotropic phase boundary (MPB) of PZT is presented. By means of x-ray powder diffraction on ceramic samples of excellent quality, the MPB has been successfully characterized by changing temperature in a series of closely spaced compositions. As a result, an unexpected monoclinic phase has been found to exist in between the well-known tetragonal and rhombohedral PZT phases. A detailed structural analysis, together with the investigation of the field effect in this region of compositions, have led to an important advance in understanding the mechanisms responsible for the physical properties of PZT as well as other piezoelectric materials with similar morphotropic phase boundaries.

  16. Temperature Field Analysis for PZT Pyroelectric Cells for Thermal Energy Harvesting

    PubMed Central

    Hsiao, Chun-Ching; Ciou, Jing-Chih; Siao, An-Shen; Lee, Chi-Yuan

    2011-01-01

    This paper proposes the idea of etching PZT to improve the temperature variation rate of a thicker PZT sheet in order to enhance the energy conversion efficiency when used as pyroelectric cells. A partially covered electrode was proven to display a higher output response than a fully covered electrode did. A mesh top electrode monitored the temperature variation rate and the electrode area. The mesh electrode width affected the distribution of the temperature variation rate in a thinner pyroelectric material. However, a pyroelectric cell with a thicker pyroelectric material was beneficial in generating electricity pyroelectrically. The PZT sheet was further etched to produce deeper cavities and a smaller electrode width to induce lateral temperature gradients on the sidewalls of cavities under homogeneous heat irradiation, enhancing the temperature variation rate. PMID:22346652

  17. Synchrotron X-ray Microdiffraction Images of Polarization Switching in Epitaxial PZT Capacitors with Pt and SrRuO3 Top Electrodes

    E-print Network

    Evans, Paul G.

    Synchrotron X-ray Microdiffraction Images of Polarization Switching in Epitaxial PZT Capacitors ferroelectric polarization in PZT thin film capacitors was imaged using synchrotron x-ray microdiffraction with a submicron-diameter focused incident x-ray beam. To form the capacitors, an epitaxial Pb(Zr,Ti)O3 (PZT) thin

  18. [Raman scattering studies on 0.5PZN-0.5PZT piezoceramics].

    PubMed

    Chang, Li-min; Hou, Yu-dong; Zhu, Man-kang; Yan, Hui

    2007-12-01

    PZT based multi-system has shown super piezoelectric properties when the composition was located at morphotropic phase boundary (MPB), which divided the regions into rhombohedral and tetragonal structures equally. In the present paper, the diffuse phase transition and phase coexistence of rhombohedral and tetragonal phases of 0.5PZN-0.5PZT ceramics were investigated by Raman scattering spectroscopy in detail. The results revealed that compared with pure PZT, the width of Raman bands of 0.5PZN-0.5PZT was quite broad, indicating that the system has strong relaxor feature. According to the temperature dependence of dielectric permittivity, the indicator of degree of diffuseness, gamma, was calculated and the values were as high as 1.71. Through the separation by Gauss fitting of the Raman bands, the intensities of different Raman vibration modes, such as the tetragonal E (3TO), A1 (3TO), E (4LO) and A1 (3LO) modes, as well as the rhombohedral R1 and Rh modes, were determined. The results indicated that for 0.5PZN-0.5PZT system, the fraction of rhombohedral phase was equal to the tetragonal phase, which has also been affirmed by XRD results and suggested that the system was close to the MPB. Excellentpiezoelectric properties, such as kp (0.66) and d33 (425 pC/N), were found in 0.5PZN-0.5PZT system, showing a great promise of this system as practical materials for piezoelectric actuators. PMID:18330288

  19. Matrix cracking and creep behavior of monolithic zircon and zircon silicon carbide fiber composites

    NASA Astrophysics Data System (ADS)

    Anandakumar, Umashankar

    In this study, the first matrix cracking behavior and creep behavior of zircon matrix silicon carbide fiber composites were studied, together with the fracture and creep behavior of the monolithic zircon. These behaviors are of engineering and scientific importance, and the study was aimed at understanding the deformation mechanisms at elevated temperatures. The first matrix cracking behavior of zircon matrix uniaxially reinforced with silicon carbide fiber (SCS-6) composites and failure behavior of monolithic zircon were studied as a function of temperature (25°C, 500°C, and 1200°C) and crack length in three point bending mode. A modified vicker's indentation technique was used to vary the initial crack length in monolithic and composite samples. The interfacial shear strength was measured at these temperatures from matrix crack saturation spacing. The composites exhibited steady state and non steady state behaviors at the three different temperatures as predicted by theoretical models, while the failure stress of zircon decreased with increasing stress. The intrinsic properties of the composites were used to numerically determine the results predicted by three different matrix cracking models based on a fracture mechanics approach. The analysis showed that the model based on crack bridging analysis was valid at 25°C and 500°C, while a model based on statistical fiber failure was valid at 1200°C. Microstructural studies showed that fiber failure in the crack wake occurred at or below the matrix cracking stress at 1200°C, and no fiber failure occurred at the other two temperatures, which validated the results predicted by the theoretical models. Also, it was shown that the interfacial shear stress corresponding to debonding determined the matrix cracking stress, and not the frictional shear stress. This study showed for the first time, the steady state and non-steady state matrix cracking behavior at elevated temperatures, the difference in behavior between room temperature and elevated temperatures, and the validity of the various models of first matrix cracking behavior. In order to understand the creep behavior of composites, it is important to study the creep behavior of matrix, fiber, and composites under identical conditions to determine the role of various constituents. Creep studies were conducted in an inert atmosphere in four point bending and uniaxial tension modes on zircon and zircon silicon carbide fiber composites at four different temperatures of 1250°C, 1300°C, 1350°C, and 1400°C, and over the stress range of 10--200 MPa. The strain rate was measured as a function of the stress and temperature to determine the stress exponent and activation energy, and microstructural analysis was done on crept samples using scanning electron microscopy. The composites exhibited a much lower creep rate than the monolilth, indicating that the major portion of the creep load was carried by the fibers. In flexural mode, both zircon and composite samples exhibited bimodal creep behavior, with the stress exponent (n) increasing with increasing stress. For zircon, at lower-stresses n was in the range of 2.1--2.6 and increased to 7--7.9 at higher stresses. Microstructural studies showed that diffusional creep was the rate controlling mechanism at lower stresses, while the higher stress exponent observed at higher stresses, was due to linkage of cavities and damage accumulation resulting in a higher strain rate. In the case of composites, the stress exponent was ?1 at lower stresses, and increased to 3--5 at higher stresses, indicating that diffusional creep (and grain boundary sliding) was rate controlling at lower stresses, and either creep cavitation and crack growth or dislocation creep was the rate controlling mechanism at higher stresses. Anomalous creep curves with strain jumps were observed for the first time during the creep of ceramic composites at lower temperatures and higher stresses. Microstructural studies showed that matrix cracking during creep results in these strain jumps. These studies showed tha

  20. The Effect of Biaxial Texture on the Effective Electromechanical Constants of Pollycrystalline Barium Titanate and Lead Titanate Thin Films

    E-print Network

    Bhattacharya, Kaushik

    Barium Titanate and Lead Titanate Thin Films Jennifer L. Ruglovsky1 , Jiangyu Li2 , Kaushik Bhattacharya1 titanate films, but not for lead titanate. Twist texturing about these out-of-plane angles shows a further for a polycrystalline film. We explore tetragonal 4MM materials, and give specific results for barium titanate and lead

  1. The Crystal Structure of Lanthanide Zirconates

    NASA Astrophysics Data System (ADS)

    Clements, Richard; Kennedy, Brendan; Ling, Christopher; Stampfl, Anton P. J.

    2010-03-01

    The lanthanide zirconates of composition Ln2Zr2O7 (Ln = La-Gd) are of interest for use in inert matrix fuels and nuclear wasteforms. The series undergoes a pyrochlore to fluorite phase transition as a function of the Ln atomic radii. The phase transition has been attributed to disordering of both the cation and the anion [1]. We have undertaken a synthesis of the lanthanide zirconate series Ln2Zr2O7 (Ln = La-Gd), Ln0.2Zr0.8O1.9 (Ln = Tb-Yb) and NdxHo2-xZr2O7 (0

  2. A mechanical method to tuning a FBG-PZT voltage sensor

    NASA Astrophysics Data System (ADS)

    Ribeiro, Bessie A.; Werneck, Marcelo M.

    2015-09-01

    When using a Fiber Bragg Grating (FBG) for strain measurements it is always necessary to compensate the FBG against temperature fluctuations. In this paper it is shown an innovative method for mechanically compensating an FBG in a high voltage measurement application using an FBG-PZT sensor. The system takes advantage of a mechanical assembly that, as the PZT displaces, the screw where the FBG is bonded on displace in the opposite direction, keeping the FBG length constant. A theoretical analysis is done and experimental results are shown.

  3. GCM Simulations of Titan's Middle and Lower Atmosphere and Comparison to Observations

    E-print Network

    Russell, Joellen

    GCM Simulations of Titan's Middle and Lower Atmosphere and Comparison to Observations Accepted circulation model (GCM) of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible Modeling puzzling, and some formation alternatives are suggested. Keywords: Titan, atmosphere; Titan, hydrology

  4. Organic chemistry in Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    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.

  5. The organic aerosols of Titan

    NASA Technical Reports Server (NTRS)

    Khare, B. N.; Sagan, C.; Thompson, W. R.; Arakawa, E. T.; Suits, F.; Calcott, T. A.; Williams, M. W.; Shrader, S.; Ogino, H.; Willingham, T. O.

    1986-01-01

    A dark reddish organic solid, called tholin, is synthesized from simulated Titanian atmospheres by irradiation with high energy electrons in a plasma discharge. The visible reflection spectrum of this tholin is found to be similar to that of high altitude aerosols responsible for the albedo and reddish color of Titan. The real (n) and imaginary (k) parts of the complex refractive index of thin films of Titan prepared by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mb is determined from X-ray to microwave frequencies. Values of n (approx. 1.65) and k (approx. 0.004 to 0.08) in the visible are consistent with deductions made by groundbased and spaceborne observations of Titan. Many infrared absorption features are present in k(lambda), including the 4.6 micrometer nitrile band. Molecular analysis of the volatile components of this tholin was performed by sequential and nonsequential pyrolytic gas chromatography/mass spectrometry. More than one hundred organic compounds are released; tentative identifications include saturated and unsaturated aliphatic hydrocarbons, substituted polycylic aromatics, nitriles, amines, pyrroles, pyrazines, pyridines, pyrimidines, and the purine, adenine. In addition,acid hydrolysis produces a racemic mixture of biological and nonbiological amino acids. Many of these molecules are implicated in the origin of life on Earth, suggesting Titan as a contemporary laboratory environment for prebiological organic chemistry on a planetary scale.

  6. GCM Simulations of Titan's Paleoclimate

    NASA Astrophysics Data System (ADS)

    Lora, Juan M.; Lunine, Jonathan; Russell, Joellen; Hayes, Alexander

    2014-11-01

    The hemispheric asymmetry observed in the distribution of Titan's lakes and seas has been suggested to be the result of asymmetric seasonal forcing, where a relative moistening of the north occurs in the current epoch due to its longer and less intense summers. General circulation models (GCMs) of present-day Titan have also shown that the atmosphere transports methane away from the equator. In this work, we use a Titan GCM to investigate the effects that changes in Titan's effective orbital parameters have had on its climate in recent geologic history. The simulations show that the climate is relatively insensitive to changes in orbital parameters, with persistently dry low latitudes and wet polar regions. The amount of surface methane that builds up over either pole depends on the insolation distribution, confirming the influence of orbital forcing on the distribution of surface liquids. The evolution of the orbital forcing implies that the surface reservoir must be transported on timescales of ~30 kyr, in which case the asymmetry reverses with a period of ~125 kyr. Otherwise, the orbital forcing is insufficient for generating the observed dichotomy.

  7. Possible temperate lakes on Titan

    NASA Astrophysics Data System (ADS)

    Vixie, Graham; Barnes, Jason W.; Jackson, Brian; Rodriguez, Sébastien; Le Mouélic, Stéphane; Sotin, Christophe; MacKenzie, Shannon; Wilson, Paul

    2015-09-01

    We analyze southern mid-latitude albedo-dark features on Titan observed by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-latitudes would indicate that surface liquid can accumulate and remain stable away from Titan's poles. Candidate lakes were identified by looking for possible shorelines with lacustrine morphology. Then, we applied an atmospheric correction that empirically solved for their surface albedo. Finally, we looked for a specular reflection of the sky in the identified candidates. Using this prescription, we find two candidates that remain as potential temperature lakes. If candidate features do represent temperate lakes on Titan, they have implications for formation mechanisms such as clouds and rainfall or, in low elevation areas, percolation and subsurface flow. Clouds were observed near candidate lake locations on the T66 flyby and this latitude band showed many clouds during southern summer. Our techniques can be applied to areas of Titan that lack RADAR coverage to search for mid- and low-latitude lakes in the future.

  8. Photoelectrical properties of strontium titanate

    NASA Astrophysics Data System (ADS)

    Dedyk, A. I.; Semenov, A. A.; Pavlova, Yu. V.; Belyavskii, P. Yu.; Nikitin, A. A.; Pakhomov, O. V.; Myl'nikov, I. L.

    2015-04-01

    The influence of UV and visible radiations on the insulating properties of metal-insulator-metal structures based on single-crystalline strontium titanate is investigated. It is found that the capacitance of the structure stably grows under irradiation by light with a wavelength from the intrinsic absorption range both at low temperatures and at room temperature. Mechanisms underlying this effect are discussed.

  9. The Surface Composition of Titan

    NASA Astrophysics Data System (ADS)

    Clark, Roger Nelson; Pearson, N.; Brown, R. H.; Cruikshank, D. P.; Barnes, J.; Jaumann, R.; Soderblom, L.; Griffith, C.; Rannou, P.; Rodriguez, S.; Le Mouelic, S.; Lunine, J.; Sotin, C.; Baines, K. H.; Buratti, B. J.; Nicholson, P. D.; Nelson, R. M.; Stephan, K.

    2012-10-01

    Mapping the surface composition of Titan with the Cassini Visual and Infrared Mapping Spectrometer (VIMS) requires knowledge of the atmospheric absorption in the windows through which VIMS can observe the surface as well as the spectral properties of candidate materials. Recent atmospheric models are refining that knowledge. Titan's surface, in the VIMS spectral range, is seen in only a few spectral windows, near 0.94, 1.1, 1.3, 1.6, 2.0, 2.68-2.78, and 4.9-5.1 microns. Atmospheric models fail to fit the the observed spectra on the long wavelength side of the 2-micron window without invoking surface absorption at 2.1 microns. This new knowledge, along with the spectral shapes of the 2.68-2.78-micron, and 5-micron windows provide powerful constraints on Titan's surface composition. Water ice is incompatible with the observed 2.78/2.68 micron I/F ratio but likely exists below the surface. Many organic compounds have absorptions that are not seen in spectral windows of Titan, eliminating them as possible major components at the surface, including many polycyclic aromatic hydrocarbons (PAH). We find that some ring compounds and compounds with single N-H bonds have a close match to Titan's overall spectrum and can explain the relative intensities observed in the spectral windows, including the 2.68 and 2.78-micron double window, the low 3-5 micron reflectance, and increased absorption near 2.1-microns. Glycine is the only NH2 compound we have found that is also compatible. Combinations of coronene (C24H12), phenanthene (C14H12), pentacene (C22H14), indole (C8H7N), uracil (C4H4N2O2), and glycine (NH2CH2C00H) match the overall spectral structure of Titan spectra. We are searching for additional compounds that are also compatible. Indole, cytosine, and uracil, have 1.5-micron bands that are similar to the feature observed in Huygens DISR spectra of Titan's surface. These compounds, if present, can also help explain the pyrolysis results from the Huygens probe.

  10. Nitrogen compounds in Titan's stratosphere

    NASA Astrophysics Data System (ADS)

    Coustenis, A.; Cirs Investigation Team

    Titan's atmosphere is essentially composed of molecular nitrogen (N2). The chemistry between the two mother molecules (N2 and CH4) leads to the formation of a certain number of nitriles observed in Titan's stratosphere as early as at the time of the Voyager 1 encounter in 1980. In the spectra taken by the Infrared Radiometer Interferometer Spectrometer (IRIS) the signatures of HCN, HC3N, C2N2 and C4N2 (in solid form) were found and reported. Subsequent observations from the ground better described the vertical profiles of these constituents and allowed for the detection of CH3CN (acetonitrile) in the mm range [3,4]. Recent data recorded by the Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft during the Titan flybys (October 2004 - June 2006) give a handle on the temporal and latitudinal variations of these constituents. The nadir spectra characterize various regions on Titan from 85°S to 75°N with a variety of emission angles. We study the emission observed in the mid-infrared CIRS detector arrays (covering roughly the 600-1500 cm-1 spectral range with apodized resolutions of 2.54 or 0.53 cm-1 ). The composite spectrum shows several molecular signatures of nitriles. Information is retrieved on the meridional variations of the trace constituents and tied to predictions by dynamical-photochemical models [1,2,5]. The nitriles show a significant enhancement at high northern latitudes albeit not as marked as at the time of the Voyager encounter. We will give a review of our current understanding of the minor nitrile chemistry on Titan. References : [1] Coustenis et al., 2006. Icarus, in press. [2] Flasar et al., 2005. Science 308, 975. [3] Marten, A., et al., 2002, Icarus, 158, 532-544. [4] Marten, A. & Moreno, R., 2003. 35th Annual DPS Meeting, Monterey, Ca, BAAS, 35, 952. [5] Teanby et al., 2006. Icarus, 181, 243-255.

  11. Titan's Chemical Complexity and Dust

    NASA Astrophysics Data System (ADS)

    Vuitton, Véronique

    Titan, Saturn's largest satellite, harbors one of the richest atmospheric chemistry in the solar system, initiated by the dissociation of the major neutral species (nitrogen and methane) by ultraviolet solar radiation and associated photoelectrons. Until recently, it was believed that the dust observed in the stratosphere (i.e. micrometer size organic aerosols) was formed in situ through an intense neutral chemistry involving complex organic molecules. However, this understanding of Titan’s atmospheric chemistry is being strongly challenged by recent measurements from the Cassini spacecraft. They revealed an extraordinarily complex thermospheric composition with positive ions extending up to at least hundreds of u/q and negative ions up to at least thousands of u/q. These observations indicate that molecular growth starts at much higher altitudes than previously anticipated and suggest that new formation processes have to be put forward. We review our recent work on Titan's upper atmospheric chemistry. We base our discussion on Cassini observations as well as on a new generation of photochemical/microphysical models and laboratory experiments. We argue that positive ion chemistry is at the origin of complex organic molecules, such as benzene, ammonia and hydrogen isocyanide, and that radiative neutral-neutral association can efficiently form alkanes. We find that macromolecules (m/z > 100) attach electrons and therefore attract the abundant positive ions, which ultimately leads to the formation of the dust. In order to infer the dust chemical composition and structure, we turn towards the analysis of laboratory analogues by ultra-high resolution mass spectrometry. Finally, we emphasize that another space mission to Titan with a new generation of instruments is required to validate the effort currently under progress in the laboratory.

  12. Experimental high-grade alteration of zircon using akali- and Ca-bearing solutions: resetting the zircon geochronometer during metasomatism

    NASA Astrophysics Data System (ADS)

    Harlov, D. E.; Dunkley, D.

    2010-12-01

    In nature zircon is one of the principle accessory minerals used for the dating of geologic processes. As a consequence, the stability of zircon in the presence of various possible metamorphic and igneous fluids under a range of P-T conditions and its subsequent alteration with respect to some of these fluids has begun to be explored experimentally as well as speculated upon in a series of natural studies of metasomatised zircons (see review in Geisler et al., 2007 Elements 3, 43-50). Natural alteration of zircon takes place either via dissolution coupled with overgrowth or via fluid-aided coupled dissolution-reprecipitation (Putnis, 2009 Rev Mineral Geochem, vol 70, 87-124). This process results in the zircon being partially or totally replaced by new compositionally re-equilibrated zircon or a new mineral phase or both. In this study, fragments (50 to 200 microns) from a large, inclusion-free, clear, light brown, relatively non-metamict euhedral zircon collected from a nepheline syenite pegmatite (Seiland magmatic province, northern Norway) were experimentally reacted in 20 mg batches with a series of alkali-and Ca-bearing fluids plus a Th + Si source (5 mg ThO2 + ThSiO2 + SiO2) in sealed Pt capsules at 900 °C and 1000 MPa for 6 to 11 days in the piston cylinder press using a CaF2 setup with cylindrical graphite oven. Fluids included 5 mg 2 N NaOH, 5 mg 2 N KOH, 10 mg Na2Si2O5 + 5 mg H2O, 1 mg NaF + 5 mg H2O, and 1 - 5 mg Ca(OH)2 + 5 mg H2O. In each experiment, the fluid reacted with the zircon. This reaction took the form of partial replacement of the zircon with compositionally altered zircon via coupled dissolution-reprecipitation plus varying amounts of overgrowth. The reacted zircon is characterized by a sharp compositional boundary between the altered and original zircon as well as, in some cases, by a micro-porosity and/or inclusions of ZrO2 or ThSiO4. SIMS analysis of the replaced zircon indicates that it is strongly enriched in Th + Si, heavily depleted in U, and heavily to moderately depleted in (Y+REE). If YPO4 replaces (Th + Si) in the system, the altered zircon is enriched in YPO4 and heavily depleted in Th and U. In all experiments radiogenic 206Pb (3 to 5 ppm in the unaltered zircon) is strongly depleted in the altered zircon. Hafnium concentrations in the altered zircon retain the same value as in the original zircon. The results from these experiments indicate that zircon can be compositionally altered via alkali- and Ca-bearing fluids via coupled dissolution-reprecipitation processes under high-grade conditions and that their internal geochronometer can be reset due to the massive loss of radiogenic Pb.

  13. Surface Science Letters Wulff shape of strontium titanate nanocuboids

    E-print Network

    Marks, Laurence D.

    Surface Science Letters Wulff shape of strontium titanate nanocuboids Lawrence Crosby a, , James Transmission electron microscopy Nanocuboid Hydrothermal synthesis Strontium titanate Kirkendall effect Here we describe the Wulff shape of strontium titanate nanocuboids prepared by a hydrothermal method and annealed

  14. Dielectric, piezoelectric, and pyroelectric properties of lead zirconate-lead zinc niobate ceramics

    SciTech Connect

    Takenaka, T. ); Bhalla, A.S.; Cross, L.E. . Materials Research Lab.); Sakata, K. . Faculty of Science and Technology)

    1989-06-01

    This paper reports on piezoelectric and pyroelectric ceramics consisting of antiferroelectric lead zirconate (PZ) and relaxor ferroelectric lead zinc niobate (PZN) studied from an application viewpoint of the field-induced antiferroelectric-to-ferroelectric phase transition. An antiferroelectric-to-ferroelectric phase transition. An antiferroelectric-ferroelectric phase boundary exists in PbZr{sub x}(Zn{sub 1/3}Nb{sub 2/3}){sub 1 {minus} x}O{sub 3}(PZZN-1000x) close to x = 0.93 to 0.94 at room temperature. A new ferroelectric rhombohedral phase change, F{alpha}-F'{alpha} at low temperature is found and studied by the temperature dependence of the pyroelectric coefficient. Electrical poling in these ceramics is easy, and the coercive field E{sub c} {approx} 8 to 10 kV/cm is rather low. Samples with compositions in the range PZZN-86 to PZZN-92 have a large electromechanical coupling constant, k (k, and k {sub 15} {approx} 50% to 60%), and a low dielectric constant, {epsilon}{sub s}, ({epsilon}{sup T}{sub 33}/{epsilon}{sub 0} = 260 to 320, {epsilon}{sup T}{sub 11} {epsilon}{sub 0} = 380). PZZN ceramics appear to be potential candidates for high-frequency ultrasonic transducers used in the thickness shear mode. The pyroelectric figure of merit (F{sub v}) of these ceramics is comparable to the values published for the PZT-based or PbTiO{sub 3}-based materials.

  15. Interaction of rhyolite melts with monazite, xenotime, and zircon surfaces

    NASA Astrophysics Data System (ADS)

    Rustad, James R.

    2015-05-01

    The interfacial contact region between a rhyolite melt and the accessory minerals monazite, xenotime, and zircon is investigated using molecular dynamics simulations. On all surfaces, major structural rearrangement extends about 1 nm into the melt from the interface. As evidenced by the structural perturbations in the ion distribution profiles, the affinity of the melt for the surface increases in going from monazite to xenotime to zircon. Alkali ions are enriched in the melt in contact with an inert wall, as well as at the mineral surfaces. Melt in contact with zircon has a particularly strong level of aluminum enrichment. In xenotime, the enrichment of aluminum is less than that in zircon, but still notable. In monazite, the aluminum enrichment in the contact layer is much less. It is expected that the relative surface energies of these accessory minerals will be a strong function of the aluminum content of the melt and that nucleation of zircon, in particular, would be easier for melts with higher aluminum concentration. The crystal growth rate for zircon is expected to be slower at a higher aluminum concentration because of the effectiveness of aluminum in solvating the zircon surface. The variable interfacial concentration profiles across the series of accessory minerals will likely affect the kinetics of trace element incorporation, as the trace elements must compete with the major elements for surface sites on the growing accessory minerals.

  16. Geologic Features on Titan's Surface as Revealed by the Cassini Titan Radar Mapper

    NASA Astrophysics Data System (ADS)

    Lopes, R. M.; Stofan, E. R.; Paganelli, F.; Mitchell, K. L.; Kirk, R.; Lorenz, R.; Lunine, J.; Soderblom, L. A.; Wall, S. D.; Wood, C.; Radebaugh, J.; Robshaw, L. E.; Elachi, C.; Cassini RADAR Team

    2006-03-01

    Results from four Titan fly-bys using SAR are summarized and show that Titan has a complex and relatively young surface, with features formed by cryovolcanism, fluvial and aeolian activity, cratering, and possibly tectonism.

  17. Voltage generation of piezoelectric cantilevers by laser heating.

    PubMed

    Hsieh, Chun-Yi; Liu, Wei-Hung; Chen, Yang-Fang; Shih, Wan Y; Gao, Xiaotong; Shih, Wei-Heng

    2012-11-15

    Converting ambient thermal energy into electricity is of great interest in harvesting energy from the environment. Piezoelectric cantilevers have previously been shown to be an effective biosensor and a tool for elasticity mapping. Here we show that a single piezoelectric (lead-zirconate titanate (PZT)) layer cantilever can be used to convert heat to electricity through pyroelectric effect. Furthermore, piezoelectric-metal (PZT-Ti) bi-layer cantilever showed an enhanced induced voltage over the single PZT layer alone due to the additional piezoelectric effect. This type of device can be a way for converting heat energy into electricity. PMID:23258941

  18. Voltage generation of piezoelectric cantilevers by laser heating

    PubMed Central

    Hsieh, Chun-Yi; Liu, Wei-Hung; Chen, Yang-Fang; Shih, Wan Y.; Gao, Xiaotong; Shih, Wei-Heng

    2012-01-01

    Converting ambient thermal energy into electricity is of great interest in harvesting energy from the environment. Piezoelectric cantilevers have previously been shown to be an effective biosensor and a tool for elasticity mapping. Here we show that a single piezoelectric (lead-zirconate titanate (PZT)) layer cantilever can be used to convert heat to electricity through pyroelectric effect. Furthermore, piezoelectric-metal (PZT-Ti) bi-layer cantilever showed an enhanced induced voltage over the single PZT layer alone due to the additional piezoelectric effect. This type of device can be a way for converting heat energy into electricity. PMID:23258941

  19. Exploratory Study of the Acoustic Performance of Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    SantaMaria, O. S.; Thurlow, E. M.; Jones, M. G.

    1989-01-01

    The proposed ducted fan engine has prompted the need for increasingly lightweight and efficient noise control devices. Exploratory tests at the NASA Langley Research Center were conducted to evaluate three piezoelectric specimens as possible control transducers: a Polyvinylidene Flouride (PVDF) piezofilm sample and two composite samples of Lead Zirconate Titanate (PZT) rods embedded in fiberglass. The tests measured the acoustic output efficiency and evaluated the noise control characteristics when interacting with a primary sound source. The results showed that a PZT sample could diminish the reflected acoustic waves. However, the PZT acoustic output must increase by several orders of magnitude to qualify as a control transducer for the ducted fan engine.

  20. A reconnaissance ion-probe of hafnium isotopes in zircons

    SciTech Connect

    Kinny, P.D.; Compston, W.; Williams, I.S. )

    1991-03-01

    A SIMS technique for the isotopic analysis of hafnium in zircons using the SHRIMP ion microprobe has been developed, and a precision of typically 0.5{per thousand} (2{sigma}) achieved in the mean reduced {sup 176}Hf/{sup 177}Hf ratio measured at several spots on a single grain. Unfractionated (chondritic) initial Hf isotopic compositions have been measured on a number of Archaean zircon populations. These include the oldest-known terrestrial minerals, the 4.2 Ga-old Mount Narryer detrital zircons, thereby confirming their antiquity. In contrast, positive initial {epsilon}{sub Hf} (relative to the chondritic model composition) has been found in several post-Archaean zircon populations, reflecting the increasing involvement of isotopically evolved depleted mantle sources in the formation of younger crust. The 570 Ma-old Sri Lankan zircon standard SL7 yielded an exceptionally low initial {epsilon}{sub Hf} of {minus}23, implying a metamorphic origin as a reworked product of ancient crust. SHRIMP U-Pb analyses of zircons from Archaean tonalitic gneiss at Watersmeet, Michigan, yield a precise crystallization age of 3636 {plus minus}6 Ma (2{sigma}), and show that a previously reported correlation between {sup 176}Hf/{sup 177}Hf and U-Pb isotopic discordance in bulk zircon samples (Patchett, 1983) was caused by the addition of radiogenic Hf in discrete overgrowths of new zircon ca. 2.7 Ga ago. The original 3.64 Ga grains show no evidence of distrubance to their original (chondritic) Hf isotopic composition. There is presently no evidence for significant isotopic exchange of Hf between zircon and other minerals in crustal rocks.

  1. Dissolution on Titan and on Earth: Towards the age of Titan's karstic landscapes

    NASA Astrophysics Data System (ADS)

    Cornet, T.; Cordier, D.; Le Bahers, T.; Bourgeois, O.; Fleurant, C.; Le Mouélic, S.; Altobelli, N.

    2015-10-01

    The morphology of Titan's lacustrine depressions led to comparisons with terrestrial depressions developed by karstic dissolution. We tested this hypothesis by computing dissolution rates of Titan's solids in liquid methane. We inferred from these rates the timescales needed to create dissolution landforms of a given depth. Dissolution would be a very efficient geological process to shape Titan's surface, on timescales generally shorter than 100 Myrs, consistent with the youth of Titan's surface (<1 Gyr).

  2. Proton conductivity of potassium doped barium zirconates

    SciTech Connect

    Xu Xiaoxiang; Tao Shanwen; Irvine, John T.S.

    2010-01-15

    Potassium doped barium zirconates have been synthesized by solid state reactions. It was found that the solubility limit of potassium on A-sites is between 5% and 10%. Introducing extra potassium leads to the formation of second phase or YSZ impurities. The water uptake of barium zirconates was increased even with 5% doping of potassium at the A-site. The sintering conditions and conductivity can be improved significantly by adding 1 wt% ZnO during material synthesis. The maximum solubility for yttrium at B-sites is around 15 at% after introducing 1 wt% zinc. The conductivity of Ba{sub 0.95}K{sub 0.05}Zr{sub 0.85}Y{sub 0.11}Zn{sub 0.04}O{sub 3-{delta}} at 600 deg. C is 2.2x10{sup -3} S/cm in wet 5% H{sub 2}. The activation energies for bulk and grain boundary are 0.29(2), 0.79(2) eV in wet 5% H{sub 2} and 0.31(1), 0.74(3) eV in dry 5% H{sub 2}. A power density of 7.7 mW/cm{sup 2} at 718 deg. C was observed when a 1 mm thick Ba{sub 0.95}K{sub 0.05}Zr{sub 0.85}Y{sub 0.11}Zn{sub 0.04}O{sub 3-{delta}} pellet was used as electrolyte and platinum electrodes. - Graphical abstract: Potassium doped barium zirconates have been synthesized by solid state reactions. It was found that the solubility limit of potassium on A-sites is between 5% and 10 %. The sintering conditions and conductivity can be improved significantly by adding 1 wt% ZnO during material synthesis. Five percent doping of potassium at A-site can double the total conductivity.

  3. Effect of ?-damage on fission-track annealing in zircon

    USGS Publications Warehouse

    Kasuya, Masao; Naeser, Charles W.

    1988-01-01

    The thermal stability of confined fission-track lengths in four zircon samples having different spontaneous track densities (i.e., different amounts of ??-damage) has been studied by one-hour isochronal annealing experiments. The thermal stability of spontaneous track lengths is independent of initial spontaneous track density. The thermal stability of induced track lengths in pre-annealed zircon, however, is significantly higher than that of spontaneous track lengths. The results indicate that the presence of ??-damage lowers the thermal stability of fission-tracks in zircon.

  4. Hubble Observes Surface of Titan

    NASA Technical Reports Server (NTRS)

    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.

    Smith's group used the Hubble Space Telescope's WideField/Planetary Camera 2 at near-infrared wavelengths (between .85 and 1.05 microns). Titan's haze is transparent enough in this wavelength range to allow mapping of surface features according to their reflectivity. Only Titan's polar regions could not be mapped this way, due to the telescope's viewing angle of the poles and the thick haze near the edge of the disk. Their image-resolution (that is, the smallest distance seen in detail) with the WFPC2 at the near-infrared wavelength is 360 miles. The 14 images processed and compiled into the Titan surface map were as 'noise' free, or as free of signal interference, as the space telescope allows, Smith said.

    Titan makes one complete orbit around Saturn in 16 days, roughly the duration of the imaging project. Scientists have suspected that Titan's rotation also takes 16 days, so that the same hemisphere of Titan always faces Saturn, just as the same hemisphere of the Earth's moon always faces the Earth. Recent observations by Lemmon and colleagues at the University of Arizona confirm this true.

    It's too soon to conclude much about what the dark and bright areas in the Hubble Space Telescope images are -- continents, oceans, impact craters or other features, Smith said. Scientists have long suspected that Titan's surface was covered with a global ehtane-methane ocean. The new images show that there is at least some solid surface.

    Smith's team made a total 50 images of Titan last month in their program, a project to search for small scale features in Titan's lower atmosphere and surface. They have yet to analyze images for information about Titan's clouds and winds. That analysis could help explain if the bright areas are major impact craters in the frozen water ice-and-rock or higher-altitude features.

    The images are important information for the Cassini mission, which is to launch a robotic spacecraft on a 7-year journey to Saturn in October 1997. About three weeks before Cassini's first flyby

  5. Nitrogen Chemistry in Titan's Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    McKay, Christopher P.; Cuzzi, Jeffrey (Technical Monitor)

    1996-01-01

    In Titan's upper atmosphere N2 is dissociated to N by solar UV and high energy electrons. This flux of N provides for interesting organic chemistry in the lower atmosphere of Titan. Previously the main pathway for the loss of this N was thought to be the formation of HCN, followed by diffusion of this HCN to lower altitudes leading ultimately to condensation. However, recent laboratory simulations of organic chemistry in Titan's atmosphere suggest that formation of the organic haze may be an important sink for atmospheric N. Because estimates of the eddy diffusion profile on Titan have been based on the HCN profile, inclusion of this additional sink for N will affect estimates for all transport processes in Titan's atmosphere. This and other implications of this sink for the N balance on Titan are considered.

  6. Titan's Atmosphere Responds to Sunspot Cycle Observations of Titan's atmosphere have

    E-print Network

    Rathbun, Julie A.

    Titan's Atmosphere Responds to Sunspot Cycle Observations of Titan's atmosphere have revealed system with an atmosphere as thick as the Earth's, although its make-up is different: 98% nitrogen, 1 system, seasonal changes in the chemistry of Titan's atmosphere have been observed as it and Saturn orbit

  7. Fabrication and characterization of piezoelectric micromachined ultrasonic transducers with thick composite PZT films.

    PubMed

    Wang, Zhihong; Zhu, Weiguang; Zhu, Hong; Miao, Jianmin; Chao, Chen; Zhao, Changlei; Tan, Ooi Kiang

    2005-12-01

    Ferroelectric microelectromechanical systems (MEMS) has been a growing area of research in past decades, in which ferroelectric films are combined with silicon technology for a variety of applications, such as piezo-electric micromachined ultrasonic transducers (pMUTs), which represent a new approach to ultrasound detection and generation. For ultrasound-radiating applications, thicker PZT films are preferred because generative force and response speed of the diaphragm-type transducers increase with increasing film thickness. However, integration of 4- to 20-microm thick PZT films on silicon wafer, either the deposition or the patterning, is still a bottleneck in the micromachining process. This paper reports on a diaphragm-type pMUT. A composite coating technique based on chemical solution deposition and high-energy ball milled powder has been used to fabricate thick PZT films. Micromachining of the pMUTs using such thick films has been investigated. The fabricated pMUT with crack-free PZT films up to 7-microm thick was evaluated as an ultrasonic transmitter. The generated sound pressure level of up to 120 dB indicates that the fabricated pMUT has very good ultrasound-radiating performance and, therefore, can be used to compose pMUT arrays for generating ultrasound beam with high directivity in numerous applications. The pMUT arrays also have been demonstrated. PMID:16463494

  8. Large strain response in PZT-PZN-PAN lead-based ceramics

    NASA Astrophysics Data System (ADS)

    Wei, Linlin; Liu, Aiyun; Han, Hailong; Lin, Fangting; Jin, Chengchao; Wang, Peng; Yao, Qirong; Shi, Wangzhou; Jing, Chengbin

    2013-12-01

    Solid solutions of 0.8Pb(Zr0.52Ti0.48)O3-(0.2-x)Pb(Zn1/3Nb2/3)O3-xPb(Al1/2Nb1/2)O3 (PZT-PZN-PAN, PZT-PZN-xPAN) with x from 0 to 0.1 were fabricated and the dielectric, ferroelectric, piezoelectric properties were investigated in detail. Results show the crystal structure changes from coexists of tetragonal and rhombohedral to single rhombohedral phase. At a critical composition of 0.02, a maximum quasi-static piezoelectric coefficient d33 (410 pC/N) was obtained. Furthermore, it is found that the increment of PAN content could lead to increase the strain of PZT-PZN-xPAN ceramics, and a large strain response of ~0.24% with normalized strain Smax/Emax as high as 767 pm/V was obtained for the PZT-PZN-0.1PAN under a low electric field of ~3 kV/mm, which makes it a promising material for solid-state actuator applications.

  9. Embedded 3D electromechanical impedance model for strength monitoring of concrete using a PZT transducer

    NASA Astrophysics Data System (ADS)

    Wang, Dansheng; Song, Hongyuan; Zhu, Hongping

    2014-10-01

    The electromechanical (EM) impedance approach in which piezoelectric ceramics (PZT) simultaneously act as both a sensor and an actuator due to their direct and inverse piezoelectric effects has emerged as a powerful tool for structural health monitoring in recent years. This paper formulates a new 3D electromechanical impedance model that characterizes the interaction between an embedded square PZT transducer and the host structure based on the effective impedance. The proposed formulations can be conveniently used to extract the mechanical impedance of the host structure from the electromechanical admittance measurements of an embedded PZT patch. The proposed model is verified by experimental and numerical results from a smart concrete cube in which a square PZT transducer is embedded. Subsequently, this paper also presents a new methodology to monitor the compressive strength of concrete based on the effective mechanical impedance. By extracting the effective mechanical impedances from the electromechanical admittance signatures, measuring the compressive strength of the concrete cubes at different ages and combining these measurements with the index of the correlation coefficient (CC), a linear correlation between the concrete strength gain and the CC of the real mechanical admittances was found. The proposed approach is found to be feasible to monitor the compressive strength of concrete by age.

  10. Processing Effects for Integrated PZT: Residual Stress, Thickness, and Dielectric Properties

    E-print Network

    Sottos, Nancy R.

    Processing Effects for Integrated PZT: Residual Stress, Thickness, and Dielectric Properties Ryan J-Champaign, Urbana, Illinois 61801 Processing effects on the dielectric properties of sol­gel-derived PbZrO3­PbTiO3 composition (Pb (Zr0.53Ti0.47)O3), phase content (perovskite), grain size (B110 nm), crystallographic

  11. In-situ structural investigations of ferroelasticity in soft and hard rhombohedral and tetragonal PZT

    NASA Astrophysics Data System (ADS)

    Morozov, Maxim I.; Einarsrud, Mari-Ann; Tolchard, Julian R.; Geiger, Philipp T.; Webber, Kyle G.; Damjanovic, Dragan; Grande, Tor

    2015-10-01

    Despite the technological importance of hard and soft PZT, Pb(Zr,Ti)O3, ceramics, the mechanisms of ferroelectric hardening and softening remain widely discussed in the literature. The hardening and softening phenomena have traditionally been investigated in relation with dielectric manifestations such as aging of the dielectric susceptibility and constriction of the polarization-electric field hysteresis loop. Here, we present a systematic investigation of the ferroelectric and ferroelastic properties of soft and hard PZT in both the tetragonal and rhombohedral phases. A particular focus has been devoted to ferroelastic domain switching by characterizing the macroscopic mechanical constitutive behavior and in-situ synchrotron X-ray diffraction during compression. It is demonstrated that variation of the ordering state of point defects in PZT ceramics affects the switching behavior of both ferroelectric and ferroelastic domains under mechanical or electrical fields. Softening of the mechanical and electrical properties of originally hard PZT ceramics was conferred by quenching the materials from above the Curie temperature. The present findings are discussed with respect to the current understanding of hardening-softening transitions in ferroelectric materials.

  12. Simulations of Titan's Paleoclimate Supplementary Materials

    E-print Network

    Russell, Joellen

    Simulations of Titan's Paleoclimate Supplementary Materials Juan M. Lora1, Jonathan I. Lunine2 30 60 0 0 0 3 3 3 3 -60 -30 0 30 60 Time (Titan years) -10-4 10-4 90 90 Latitude Pressure(mbar) -60 -60 -30 0 30 60 -60 -30 0 30 60 Time (Titan years) 10 -4-10 -4 80 80 90 90 Latitude Pressure(mbar) -60

  13. Amino acidis derived from Titan tholins

    NASA Technical Reports Server (NTRS)

    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.

  14. Titan Oceanography from the Cassini

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph

    While the Cassini-Huygens mission was formulated against the speculative backdrop of a hydrocarbon ocean on Titan, the reality exposed by its measurements a quarter century later has proven more interesting. Instead of a global ocean, Titan has three modest seas, with dozens of small lakes, clustered around its north pole. The south is almost entirely bereft of surface liquids, the probable result of astronomically-forced climate cycles on Titan which are pumping ethane and methane vapor northwards across the equatorial deserts to accumulate in the long rainy season each boreal summer in the present epoch. Cassini’s RADAR instrument mapped the second-largest (~350km) sea, Ligiea Mare, while it was still in winter darkness, and has now covered the sprawling (~1000km) Kraken Mare, revealing shorelines indicating rising sea levels. The mapping allows the construction of numerical models of ocean circulation driven by winds and tides. Radar observations have placed tight limits (mm) on wave heights so far: near-infrared sunglint observations provide separate constraints on surface roughness. We will review latest observations and future plans: it is expected that winds will freshen as we move towards the culmination of the Cassini Solstice Mission in northern midsummer. The Ku-band (2.2cm) radar signals from Cassini penetrate a few meters into the possibly muddy dregs of Ontario Lacus in the south, yet remarkably allowed detection of a bottom echo at Ligeia Mare in a nadir-pointed altimetry observation in summer 2013. This not only allowed a depth estimation of ~170m, but also points to a very ‘clean’ composition, quite possibly rich in methane. This contrasts with near-infrared measurements at Ontario Lacus in the south, which show ethane and possibly an optically-muddy appearance. The stage is now set for detailed modeling of wind-driven and tidal circulations, mixing, stratification, sedimentation and shoreline processes on Titan. Beyond their insights into this environment, Cassini’s observations set the stage for future missions, which might include vehicles that float on, fly over, or even swim in, Titan’s exotic seas.

  15. Can Titan generate tori in Saturn's magnetosphere?

    NASA Astrophysics Data System (ADS)

    Smith, H. T.; Johnson, R. E.; Rymer, A. M.; Mitchell, D. G.

    2011-12-01

    Prior to Cassini's arrival at Saturn, nitrogen ions were thought to dominate heavy plasma in Saturn's magnetosphere and that Titan's atmosphere was the source of this nitrogen. Therefore, the presence of a Titan nitrogen torus was anticipated. However, it is now known water-group ions dominate Saturn's heavy ion plasma. While nitrogen ions have been detected beyond the orbit of Rhea, they appear to be originating from the Enceladus plumes with little nitrogen plasma detected in the magnetosphere near Titan's orbit. These results appear inconsistent with the expectation that Titan's dense relatively unprotected atmosphere should provide a significant source of heavy particles to Saturn's magnetosphere. This inconsistency suggests that the plasma environment at Titan's orbit is much more complex than originally anticipated. In this talk, we expand on our previous research that categorizes the plasma environments near Titan to include all locations along Titan's orbit. Using these categories, we develop characteristic plasma spectra of each type of environment and use these results in a 3D Monte Carlo model to more accurately examine fate of nitrogen and methane escaping Titan's atmosphere. These results are compared to Cassini observations to determine if Titan is capable of generating tori.

  16. The magnetic memory of Titan's ionized atmosphere.

    PubMed

    Bertucci, C; Achilleos, N; Dougherty, M K; Modolo, R; Coates, A J; Szego, K; Masters, A; Ma, Y; Neubauer, F M; Garnier, P; Wahlund, J-E; Young, D T

    2008-09-12

    After 3 years and 31 close flybys of Titan by the Cassini Orbiter, Titan was finally observed in the shocked solar wind, outside of Saturn's magnetosphere. These observations revealed that Titan's flow-induced magnetosphere was populated by "fossil" fields originating from Saturn, to which the satellite was exposed before its excursion through the magnetopause. In addition, strong magnetic shear observed at the edge of Titan's induced magnetosphere suggests that reconnection may have been involved in the replacement of the fossil fields by the interplanetary magnetic field. PMID:18787164

  17. The Global Energy Balance of Titan

    NASA Technical Reports Server (NTRS)

    Li, Liming; Nixon, Conor A.; Achterberg, Richard K.; Smith, Mark A.; Gorius, Nicolas J. P.; Jiang, Xun; Conrath, Barney J.; Gierasch, Peter J.; Simon-Miller, Amy A.; Flasar, F. Michael; Baines, Kevin H.; Ingersoll, Andrew P.; West, Robert A.; Vasavada, Ashwin R.; Ewald, Shawn P.

    2011-01-01

    We report the first measurement of the global emitted power of Titan. Longterm (2004-2010) observations conducted by the Composite Infrared Spectrometer (CIRS) onboard Cassini reveal that the total emitted power by Titan is (2.84 plus or minus 0.01) x 10(exp 8) watts. Together with previous measurements of the global absorbed solar power of Titan, the CIRS measurements indicate that the global energy budget of Titan is in equilibrium within measurement error. The uncertainty in the absorbed solar energy places an upper limit on the energy imbalance of 5.3%.

  18. Pluto's implications for a Snowball Titan

    NASA Astrophysics Data System (ADS)

    Wong, Michael L.; Yung, Yuk L.; Randall Gladstone, G.

    2015-01-01

    The current Cassini-Huygens Mission to the Saturn system provides compelling evidence that the present state of Titan's dense atmosphere is unsustainable over the age of the Solar System. Instead, for most of its existence, Titan's atmosphere might have been in a Snowball state, characterized by a colder surface and a smaller amount of atmospheric CH4, similar to that of Pluto or Triton. We run a 1-D chemical transport model and show that the rates of organic synthesis on a Snowball Titan are significantly slower than those on present-day Titan. The primary method of methane destruction-photosensitized dissociation in the stratosphere-is greatly dampened on Snowball Titan. The downward flux of higher-order molecules through the troposphere is dominated not by hydrocarbons such as ethane, as is the case on Titan today, but by nitriles. This result presents a testable observation that could confirm the Snowball Titan hypothesis. Because Pluto's atmosphere is similar to Titan's in composition, it serves as a basis for comparison. Future observations of Pluto by the New Horizons Mission will inform photochemical models of Pluto's atmosphere and can help us understand the photochemical nature of paleo-Titan's atmosphere.

  19. Magnetic field-dependent polarization of (111)-oriented PZT-Co ferrite nanobilayer: Effect of Co ferrite composition

    NASA Astrophysics Data System (ADS)

    Khodaei, M.; Seyyed Ebrahimi, S. A.; Jun Park, Yong; Son, Junwoo; Baik, Sunggi

    2015-05-01

    The perfect (111)-oriented PZT/CFO (CFO=CoFe2O4, Co0.8Fe2.2O4 and Co0.6Mn0.2Fe2.2O4) bilayer multiferroic thin films were grown on Pt(111)/Si substrate at 600 °C using pulsed laser deposition technique. The precision X-ray diffraction analysis (avoiding the shift of peak due to the sample misalignment) revealed that the CFO films on Pt(111)/Si substrate were under an out-of-plane contraction and deposition of PZT top layer led to more increase in the out-of-plane contraction, i.e. increase in the residual stresses. The PZT and CFO layers have significant effects on magnetic and ferroelectric properties of PZT/CFO bilayer films, respectively, leading to an enhanced in-plane magnetic anisotropy as well as increased and asymmetric polarization. The effect of composition of CFO layer on magnetic field-dependent polarization of PZT/CFO bilayer films was investigated by applying the magnetic field during P-E measurement. The polarization of PZT films were increased by applying the magnetic field as a result of strain transferred from magnetostrictive CFO underlayer. This increase in polarization for PZT/Co0.6Mn0.2Fe2.2O4 was higher than that for PZT/Co0.8Fe2.2O4 and both of them were significantly higher than that for PZT/CoFe2O4 bilayer film, which was discussed based on their magnetostriction properties.

  20. Improved zircon iron corals for the 1990s

    SciTech Connect

    Decker, C. )

    1992-03-01

    CIBA-GEIGY/Drakenfeld Colors is dedicated to the research and development of consistent and cost-effective ceramic stains for the whitewares industry. After identifying the trends in color for the 1990s. CIBA-GEIGY/Drakenfeld Colors initiated an extensive R D project to improve zircon ion corals for the whitewares industry. These color trends indicated a need for stronger and cleaner zircon iron corals. This paper discusses the chemistry and crystal structure of zircon iron corals. A historical review of Drakenfeld corals will also be presented. The most recent development in Drakenfeld corals will then be compared to other commercially available zircon iron corals. Taking into consideration these comparisons, conclusions will be drawn suggesting the coral of choice for the 1990s.

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

    NASA Astrophysics Data System (ADS)

    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) Icarus, 225, 367-377. [3] Choukroun M. and C. Sotin (2012) Geophys. Res. Lett., 39, L0420. [4] Barnes J.W. et al. (2011) Icarus, 216, 136-140. [5] MacKenzie S.M. et al. (2014) submitted to JGR.

  2. Cassini Imaging Results at Titan

    NASA Technical Reports Server (NTRS)

    McEwen, A.; Turtle, E.; Perry J.; Fussner, S.; Porco, C.; West, R.; Johnson, T.; Collins, G.; DelGenio, T.; Barbara, J.

    2005-01-01

    The Cassini Imaging Science Subsystem (ISS) images show striking albedo markings on the surface of Titan. In equatorial regions the albedo patterns have high contrast and exhibit prominent lineaments and linear/angular boundaries suggestive of tectonic influences or fracturing of brittle surficial materials. There are intriguing dark curving lines near the south pole. Here we present several working hypotheses to explain these patterns. We also briefly summarize atmospheric science results.

  3. Different appearance of Titan's dunes

    NASA Astrophysics Data System (ADS)

    Paganelli, F.; Callahan, P.; Hensley, S.; Lorenz, R.; Lunine, J.; Kirk, R.; Stiles, B.; Gim, Y.; West, R.; Janssen, M.; Lopes, R.; Stofan, E.; Wall, S.; Paillou, P.; Radebaugh, J.; Cassini RADAR Team

    2008-12-01

    In this paper we analyze Cassini's Titan Radar Mapper recent flybys and yet more evidence of dark linear dunes, in the latitude between 30° S and 30° N, whose orientations are somewhat comparable to previous dune observations but at closer study show morphological differences. The appearance of Titan's dunes depends on the projected look direction of the Cassini Radar antenna, incidence angle and resolution. Dune fields are generally oriented East/West on Titan, and for many radar observations the flyby is in the equatorial plane. At closest approach the imaging direction is most nearly normal to the dune direction such as in the central portion of the T8 swath. Away from that configuration, and especially past the -/+10 minutes from close approach, the relative azimuth angle that the projected look direction of the Cassini Radar antenna has with respect to the surface changes rapidly along with incidence angle and resolution resulting in signal attenuation of the imaged features. Observational biases in the SAR images are key for dunes comparison across Titan's equatorial belt. The results show that in some regions the projected look direction could be on the order of 60° and parallel to the long axis of the radar dark features direction (i.e. T16, T25, T28), therefore suggesting that the variation in backscatter must be a combination of compositional dunes dark material and bright interdune material, varying roughness and topography when present. This suggests that we cannot assume that all the dune fields currently imaged can be characterized simply on the bases of their orientation and therefore we suggest that the characterization of the imaged surface features should be divided into at least two categories: -1) topography driven (in which Radar-clinometry can be applied); -2) compositional or due to varying roughness.

  4. Safe prescribing: a titanic challenge.

    PubMed

    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. PMID:22738396

  5. Hadean diamonds in zircon from Jack Hills, Western Australia.

    PubMed

    Menneken, Martina; Nemchin, Alexander A; Geisler, Thorsten; Pidgeon, Robert T; Wilde, Simon A

    2007-08-23

    Detrital zircons more than 4 billion years old from the Jack Hills metasedimentary belt, Yilgarn craton, Western Australia, are the oldest identified fragments of the Earth's crust and are unique in preserving information on the earliest evolution of the Earth. Inclusions of quartz, K-feldspar and monazite in the zircons, in combination with an enrichment of light rare-earth elements and an estimated low zircon crystallization temperature, have previously been used as evidence for early recycling of continental crust, leading to the production of granitic melts in the Hadean era. Here we present the discovery of microdiamond inclusions in Jack Hills zircons with an age range from 3,058 +/- 7 to 4,252 +/- 7 million years. These include the oldest known diamonds found in terrestrial rocks, and introduce a new dimension to the debate on the origin of these zircons and the evolution of the early Earth. The spread of ages indicates that either conditions required for diamond formation were repeated several times during early Earth history or that there was significant recycling of ancient diamond. Mineralogical features of the Jack Hills diamonds-such as their occurrence in zircon, their association with graphite and their Raman spectroscopic characteristics-resemble those of diamonds formed during ultrahigh-pressure metamorphism and, unless conditions on the early Earth were unique, imply a relatively thick continental lithosphere and crust-mantle interaction at least 4,250 million years ago. PMID:17713532

  6. Zircon U-Pb ages and Hf isotopic compositions indicate multiple sources for Grenvillian detrital zircon deposited in western Laurentia

    NASA Astrophysics Data System (ADS)

    Howard, Amanda L.; Farmer, G. Lang; Amato, Jeffrey M.; Fedo, Christopher M.

    2015-12-01

    Combined U-Pb ages and Hf isotopic data from 1.0 Ga to 1.3 Ga (Grenvillian) detrital zircon in Neoproterozoic and Cambrian siliciclastic sedimentary rocks in southwest North America, and from igneous zircon in potential Mesoproterozoic source rocks, are used to better assess the provenance of detrital zircon potentially transported across Laurentia in major river systems originating in the Grenville orogenic highlands. High-precision hafnium isotopic analyses of individual ?1.1 Ga detrital zircon from Neoproterozoic siliciclastic sedimentary rocks in Sonora, northern Mexico, reveal that these zircons have low ?Hf (0) (-22 to -26) and were most likely derived from ?1.1 Ga granitic rocks embedded in local Mojave Province Paleoproterozoic crust. In contrast, Grenvillian detrital zircons in Cambrian sedimentary rocks in Sonora, the Great Basin, and the Mojave Desert, have generally higher ?Hf (0) (-15 to -21) as demonstrated both by high precision solution-based, and by lower precision laser ablation, ICPMS data and were likely derived from more distal sources further to the east/southeast in Laurentia. Comparison to new and existing zircon U-Pb geochronology and Hf isotopic data from Grenvillian crystalline rocks from the Appalachian Mountains, central and west Texas, and from Paleoproterozoic terranes throughout southwest North America reveals that zircon in Cambrian sandstones need not entirely represent detritus transported across the continent from Grenville province rocks in the vicinity of the present-day southern Appalachian Mountains. Instead, these zircons could have been derived from more proximal, high ?Hf (0), ?1.1 Ga, crystalline rocks such as those exposed today in the Llano Uplift in central Texas and in the Franklin Mountains of west Texas. Regardless of the exact source(s) of the Grenvillian detrital zircon, new and existing whole-rock Nd isotopic data from Neoproterozoic to Cambrian siliciclastic sedimentary rocks in the Mojave Desert demonstrate that the occurrences of higher ?Hf (0), Grenvillian detrital zircons are decoupled from the sources of the bulk of the sedimentary detritus in which the zircons are entrained. The Cambrian Wood Canyon Formation and the underlying "off craton" Neoproterozoic Johnnie Formation and Stirling Quartzite all contain higher ?Hf (0), Grenvillian detrital zircon, in some cases as the dominant detrital zircon population. However, only portions of the Wood Canyon Formation have whole rock Nd isotopic compositions consistent with a bulk sediment source in ?1.1 Ga sources rocks. Whole rock Nd isotopic compositions of the remaining portions of this unit, and all of the Johnnie Formation and Stirling Quartzite, require bulk sediment sources principally in Paleoproterozoic continental crust. We consider the observed decoupling in the sources of Grenvillian detrital zircon and bulk sediment in the Wood Canyon Formation and underlying siliciclastic sediments as a demonstration that detrital zircon U-Pb and Hf isotopic data alone can provide an incomplete picture of the source of sediments that comprise a given siliciclastic stratigraphic unit.

  7. The Minerageny of Two Groups of Zircons from Plagioclase- Amphibolite of Mayuan Group in Northern Fujian

    E-print Network

    Xuezhao Bao; Gan Xiaochun

    2007-08-15

    Zircons can crystallize in a wide range of physical and chemical conditions. At the same time, they have high stability and durability. Therefore zircons can grow and survive in a variety of geological processes. In addition, the diffusivity of chemical compositions in their crystals is very low. Consequently,we can trace back the evolution history of the planetary materials containing zircon with zircon U-Th-Pb geochronology and geochemistry studies. However, this depends on our ability to decipher its genesis, namely magmatic or metamorphic origins. In this paper, magmatic and metamorphic zircons were found from plagioclase-amphibolite samples. Their geneses have been determined by zircon morphology, chemical composition zonations and geological field setting combined with their zircon U-Th-Pb ages. We have found obvious differences in micro-scale Raman spectra between these magmatic and metamorphic zircons. The magmatic zircons exhibit a high sloping background in their Raman spectra, but the metamorphic zircons exhibit a low horizontal background in their Raman spectra, which suggest that the magmatic zircons may contain a much higher concentration of fluorescent impurities than the metamorphic zircons. Moreover, reverse variation trends in Raman spectrum peak intensities from core to rim of a crystal between the magmatic and metamorphic zircons have been found. We think that this can be attributed to their reverse chemical composition zonations. These differences can be used to distinguish magmatic and metamorphic zircons.

  8. Nitrile Compounds Observed on Titan

    NASA Astrophysics Data System (ADS)

    Marten, A.; Moreno, R.

    2003-05-01

    Heterodyne millimeter observations were performed on Titan with the IRAM Plateau-de-Bure Interferometer array in February-March 2003 near greatest eastern elongations. The most extended configuration of the array was used. The Titan's angular diameter, corresponding to the solid body value, was 0.8 arc sec. However, a larger diameter of about 1 arc sec needs to be considered in the analysis of emitted flux measurements. Two dual frequency receivers were utilized at 3- and 1.2-mm wavelengths, giving access to the 82-116 and 210-245 GHz spectral ranges. Therefore, to optimize our mapping program, observations were carried out in the HCN(1-0), HC3N(12-11), CH3CN(12-11), HC3N(25-24) and CO(2-1) transitions, near 88.6, 109.2, 220.7, 227.4 and 230.5 GHz, respectively. An angular resolution of 0.6 arc sec was obtained at shorter wavelengths, yielding disk-resolved spectra of Titan. Most of the HCN(1-0) and HC3N(12-11) data correspond to full-disk measurements since the equivalent synthesized beam of the array was larger than 1.3 arc sec at longer wavelengths. Narrow isolated lines of HC3N and CH3CN as well as the three components of HCN(1-0) were analyzed at a very high spectral resolution of 40 kHz. Lower values of 160 kHz and 2.5 MHz were chosen for recording broad-band spectra of HCN, CH3CN and CO. Disk-averaged spectra taken at the same frequencies with the IRAM single-dish 30-m telescope (Marten et al., 2002, Icarus, 158, 532) have been used for comparison. The vertical distributions of nitrile abundances inferred from those data served as a preliminary basis for radiative transfer computations considering a spherical geometry for Titan's atmosphere and an elliptical gaussian synthesized beam. Numerical calculations of HCN and CO spectra are found in remarkable agreement with the interferometric data. Significant differences exist for HC3N in the northern latitudes and CH3CN in midlatitude regions. Measured maps are presented at all observing frequencies along with representative cases for well-fit synthetic computations, with an emphasis on the nitrile composition variations across Titan's disk.

  9. Titania bound sodium titanate ion exchanger

    DOEpatents

    DeFilippi, Irene C. G. (Palatine, IL); Yates, Stephen Frederic (Rolling Meadows, IL); Shen, Jian-Kun (Lake Zurich, IL); Gaita, Romulus (Morton Grove, IL); Sedath, Robert Henry (Bensenville, IL); Seminara, Gary Joseph (Chicago, IL); Straszewski, Michael Peter (Novi, MI); Anderson, David Joseph (Oak Lawn, IL)

    1999-03-23

    This invention is method for preparing a titania bound ion exchange composition comprising admixing crystalline sodium titanate and a hydrolyzable titanium compound and, thereafter drying the titania bound crystalline sodium titanate and subjecting the dried titania bound ion exchange composition to optional compaction and calcination steps to improve the physical strength of the titania bound composition.

  10. Condensation of Ices in Titan's Stratosphere

    NASA Astrophysics Data System (ADS)

    Barth, Erika L.

    2014-11-01

    Processes in Titan's upper atmosphere, such as photochemical destruction of methane along with the destruction of nitrogen molecules from energetic electrons, result in the production of a number of hydrocarbon and nitrile compounds which are capable of condensing at the colder temperatures of Titan's mid to lower stratosphere. Stratospheric ices can contribute to the opacity of Titan's atmosphere as well as affect the chemistry of the more optically thick clouds seen in the troposphere, should they survive long enough to serve as condensation nuclei. There are a number of observations from both Cassini and Voyager data that point to the condensation of trace species in Titan’s atmosphere, including HCN, C2H5CN, HC3N, C2H2, C2H6, and C4N2. These and about a dozen other species have now been added to the Titan CARMA microphysics model, which shows condensation occurring between 50 and 100 km in Titan's atmosphere. Results on condensation altitudes as well as particle size will be presented, and implications for the optical properties of Titan's stratospheric aerosol particles will be discussed.

  11. Nitrogen loss from Titan V. I. Shematovich

    E-print Network

    Johnson, Robert E.

    Nitrogen loss from Titan V. I. Shematovich Institute of Astronomy, Russian Academy of Sciences; published 13 August 2003. [1] Dissociation and dissociative ionization of molecular nitrogen by solar UV sources of translationally excited (hot) nitrogen atoms and molecules in the upper atmosphere of Titan

  12. Photochemically Driven Collapse of Titan's Atmosphere

    E-print Network

    Lorenz, Ralph D.

    state with a thin atmosphere. Titan's present surface temperature differs from its effective temperature of the slight greenhouse effect resulting from the N2 opacity below (longward of) 200 cm 1 . These calculationsPhotochemically Driven Collapse of Titan's Atmosphere Ralph D. Lorenz,* Christopher P. Mc

  13. The mean molecular mass of Titan's atmosphere

    E-print Network

    Withers, Paul

    , Mars, Mars #12;Science Questions · Mean molecular mass (µ) -> Chemical composition · How did Titan formThe mean molecular mass of Titan's atmosphere an in situ measurement from Huygens without using the mass spectrometer proof of concept for a useful technique Paul Withers Boston University (withers

  14. A wind origin for Titan's haze structure

    E-print Network

    Hourdin, Chez Frédéric

    .............................................................. A wind origin for Titan's haze ............................................................................................................................................................................. Titan, the largest moon of Saturn, is the only satellite in the Solar System with a dense atmosphere that drives atmospheric circulation3,4 , shrouds the moon. The haze has numerous features that have remained

  15. Rivers, Lakes, Dunes, and Rain: Crustal Processes in Titan's

    E-print Network

    Reiners, Peter W.

    Rivers, Lakes, Dunes, and Rain: Crustal Processes in Titan's Methane Cycle Jonathan I. Lunine1-6597/09/0530-0299$20.00 Key Words hydrology, climate, hydrocarbons, atmospheres, planets, clouds Abstract Titan exhibits ample SETTING FOR A METHANE CYCLE ON TITAN Titan is Saturn's largest natural satellite and the second

  16. Simulations of Titan's paleoclimate Juan M. Lora a,

    E-print Network

    Russell, Joellen

    Simulations of Titan's paleoclimate Juan M. Lora a, , Jonathan I. Lunine b , Joellen L. Russell Available online 4 September 2014 Keywords: Titan Atmospheres, dynamics Atmospheres, evolution a b s t r a c methane distribution of Titan. Using a new general circulation model of Titan's atmosphere, we simulate

  17. Flight through Titan's Atmosphere Imke de Pater1

    E-print Network

    Adamkovics, Mate

    1 Flight through Titan's Atmosphere Imke de Pater1 , Máté Ádámkovics2 , Seran Gibbard3 , Henry G of Arizona, Tucson, AZ 85721 Abstract We assembled spectral image datacubes of Titan in H-band (1.413- 1 Titan's disk. We constructed images of Titan at each wavelength by `glueing' the spectra together

  18. Tuesday, March 13, 2007 POSTER SESSION I: TITAN

    E-print Network

    Rathbun, Julie A.

    and Comparisons with Cassini ISS and Radar Imagery [#1538] Arecibo 13 cm radar measurements of Titan's reflection Following Two Years of Titan Cloud Events with Cassini/VIMS [#1689] We present measurements from VIMS of the occurrence and location of Titan's clouds and propose the first global mapping of Titan's clouds coverage

  19. Bias in Crustal Growth Models Based on age and Isotopic Composition of Detrital Zircon: The Role of Zircon Fertility

    NASA Astrophysics Data System (ADS)

    Samson, S. D.

    2011-12-01

    Early models of continental crustal growth based on the ages of crystallization of granitoids were abandoned once it was understood that many silicic magmas form by remelting pre-existing crustal materials. Subsequent crustal evolution models focused on the age and whole-rock isotopic composition of granitoids or on the isotopic composition of fine-grained clastic sedimentary rocks; rare studies examined both igneous and sedimentary rock compositions. Recently there has been a resurgence of emphasizing major crustal growth events by compiling the ages of detrital zircon. This has led to interesting speculations, such as some supercontinent forming events represent the world's largest orogenies and periods of crustal growth, that there may have been significant hiatuses of crustal production in geologic time, and that there was episodicity in magma generation that is asynchronous with apparent growth peaks based on isotopic compositions of sedimentary rocks. Some workers have emphasized that the apparent trends observed in detrital zircon ages could be a function of selective preservation rather than a strict indication of the timing of major magmatic episodes. Others have noted that relying on ages of detrital crystals is equivalent to basing growth models on granitoid ages and does not discriminate between juvenile magmas and melts formed by complete crustal recycling. More sophisticated approaches involve dating detrital zircon crystals followed by determining their hafnium isotopic composition thereby assessing if the zircon crystallized from a juvenile or recycled magma. While this latter approach holds promise for constraining episodes of juvenile crustal construction it is based on the assumption that the abundance of detrital zircon of a certain age directly reflects the volume of magma generated at that time. In other words, the assumption is implicitly made that the 'zircon fertility' of most magmas is uniform. The assumption of uniform fertility is incorrect, however, as there is a clear bias in the amount of 1.3 - 1.0 Ga (i.e. Grenvillian) zircon in the detrital zircon record. As a whole, Grenvillian magmas have much higher Zr contents (i.e. > 500 ppm) compared to typical world-wide granitoids (100 - 200 ppm Zr). The super Zr fertility of Grenvillian magmas resulted in an extreme abundance of zircon crystals. This large zircon reservoir resulted in a significant bias in the detrital zircon record. This is best demonstrated in Cambrian sedimentary rocks in northwestern Canada. Despite being a continent-width away from exposed Grenville crust, clastic sedimentary rocks still contain a very high percentage of ~ 1 Ga zircon. This is also true in continents such as Australia, where the proportion of Grenville age crust is low but the abundance of Grenville detrital zircon is still very high. Thus estimates of the amount of juvenile crust generated based on geochronologic and isotopic analysis of detrital zircon could be biased if variation in zircon fertility is not taken into consideration.

  20. Size and shape of Saturn's moon Titan

    USGS Publications Warehouse

    Zebker, Howard A.; Stiles, Bryan; Hensley, Scott; Lorenz, Ralph; Kirk, Randolph L.; Lunine, Jonathan

    2009-01-01

    Cassini observations show that Saturn's moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 ± 0.05 kilometers (km), 2574.36 ± 0.03 km, and 2574.91 ± 0.11 km, respectively; its mean radius is 2574.73 ± 0.09 km. Titan's shape approximates a hydrostatic, synchronously rotating triaxial ellipsoid but is best fit by such a body orbiting closer to Saturn than Titan presently does. Titan's lack of high relief implies that most—but not all—of the surface features observed with the Cassini imaging subsystem and synthetic aperture radar are uncorrelated with topography and elevation. Titan's depressed polar radii suggest that a constant geopotential hydrocarbon table could explain the confinement of the hydrocarbon lakes to high latitudes.

  1. Growth mechanisms and dune orientation on Titan

    NASA Astrophysics Data System (ADS)

    Lucas, Antoine; Rodriguez, Sebastien; Narteau, Clement; Cahrnay, Benjamin; Courrech du Pont, Sylvain; Tokano, Tetsuya; Garcia, Amandine; Thiriet, Melanie; Hayes, Alexander; Lorenz, Ralph; Aharonson, Oded

    2015-04-01

    Dune fields on Titan cover more than 17 % of the moon's surface, constituting the largest known surface reservoir of organics. Their confinement to the equatorial belt, shape, and eastward direction of propagation offer crucial information regarding both the wind regime and sediment supply. Herein, we present a comprehensive analysis of Titan's dune orientations using automated detection techniques on non-local denoised radar images. By coupling a new dune growth mechanism with actual wind fields generated by climate modelling, we find that Titan's dunes grow by elongation on a non-mobile substratum. To be fully consistent with both the local crestline orientations and the eastward propagation of Titan's dunes, the sediment should be predominantly transported by strong eastward winds, most likely generated by equinoctial storms or occasional fast westerly gusts. Additionally, convergence of the meridional transport predicted in models can explain why Titan's dunes are confined within plus or minus 30 deg. latitudes, where sediment fluxes converge.

  2. Growth mechanisms and dune orientation on Titan

    NASA Astrophysics Data System (ADS)

    Lucas, Antoine; Rodriguez, Sébastien; Narteau, Clément; Charnay, Benjamin; Pont, Sylvain Courrech; Tokano, Tetsuya; Garcia, Amandine; Thiriet, Mélanie; Hayes, Alexander G.; Lorenz, Ralph D.; Aharonson, Oded

    2014-09-01

    Dune fields on Titan cover more than 17% of the moon's surface, constituting the largest known surface reservoir of organics. Their confinement to the equatorial belt, shape, and eastward direction of propagation offer crucial information regarding both the wind regime and sediment supply. Herein, we present a comprehensive analysis of Titan's dune orientations using automated detection techniques on nonlocal denoised radar images. By coupling a new dune growth mechanism with wind fields generated by climate modeling, we find that Titan's dunes grow by sediment transport on a nonmobile substratum. To be fully consistent with both the local crestline orientations and the eastward propagation of Titan's dunes, the sediment should be predominantly transported by strong eastward winds, most likely generated by equinoctial storms or occasional fast westerly gusts. Additionally, convergence of the meridional transport predicted in models can explain why Titan's dunes are confined within ±30° latitudes, where sediment fluxes converge.

  3. Titan Mission Studies - A Historical Review

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    The literature of previous mission studies to Titan is surveyed, with common themes and approaches highlighted. The relationship of this 35-year record of studies to the missions that have actually flown to Titan and elsewhere is considered, and the mission concepts studied in some detail in the last two years are set in a wider context. The Titan environment is such as to permit a wide range of vehicle types including orbiters, landers, boats, airplanes, balloons and penetrators. Particularly recurrent themes in Titan exploration are the use of multiple platforms to address a wide range of scientific goals, the use of aerocapture to efficiently deliver mass to Titan orbit, and the use of lighter-than-air vehicles for wide-ranging near-surface mobility.

  4. Interaction of Titan's ionosphere with Saturn's magnetosphere.

    PubMed

    Coates, Andrew J

    2009-02-28

    Titan is the only Moon in the Solar System with a significant permanent atmosphere. Within this nitrogen-methane atmosphere, an ionosphere forms. Titan has no significant magnetic dipole moment, and is usually located inside Saturn's magnetosphere. Atmospheric particles are ionized both by sunlight and by particles from Saturn's magnetosphere, mainly electrons, which reach the top of the atmosphere. So far, the Cassini spacecraft has made over 45 close flybys of Titan, allowing measurements in the ionosphere and the surrounding magnetosphere under different conditions. Here we review how Titan's ionosphere and Saturn's magnetosphere interact, using measurements from Cassini low-energy particle detectors. In particular, we discuss ionization processes and ionospheric photoelectrons, including their effect on ion escape from the ionosphere. We also discuss one of the unexpected discoveries in Titan's ionosphere, the existence of extremely heavy negative ions up to 10000amu at 950km altitude. PMID:19073464

  5. Size and shape of Saturn's moon Titan.

    PubMed

    Zebker, Howard A; Stiles, Bryan; Hensley, Scott; Lorenz, Ralph; Kirk, Randolph L; Lunine, Jonathan

    2009-05-15

    Cassini observations show that Saturn's moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 +/- 0.05 kilometers (km), 2574.36 +/- 0.03 km, and 2574.91 +/- 0.11 km, respectively; its mean radius is 2574.73 +/- 0.09 km. Titan's shape approximates a hydrostatic, synchronously rotating triaxial ellipsoid but is best fit by such a body orbiting closer to Saturn than Titan presently does. Titan's lack of high relief implies that most--but not all--of the surface features observed with the Cassini imaging subsystem and synthetic aperture radar are uncorrelated with topography and elevation. Titan's depressed polar radii suggest that a constant geopotential hydrocarbon table could explain the confinement of the hydrocarbon lakes to high latitudes. PMID:19342551

  6. On the origin of Titan's atmosphere.

    PubMed

    Owen, T C

    2000-01-01

    The present atmosphere of Titan exhibits evidence of extensive evolution, in the form of rapid photochemical destruction of methane and a large fractionation of the nitrogen and oxygen isotopes. Attempts to recover the initial inventory of volatiles lead toward a model in which nitrogen was originally supplied as NH3, essentially unmodified from its relative abundance in the outer solar nebula. Titan's atmospheric methane, in contrast, appears to have been formed from carbon and other carbon compounds, either by gas phase reactions in the subnebula or by accretional heating during the formation of Titan. These conclusions can be tested by further studies of abundances and isotope ratios in Titan's atmosphere, augmented by studies of comets. The possible similarity of carbon and nitrogen inventories on Titan to those on the inner planets makes this investigation particularly intriguing. PMID:11543520

  7. Titan Orbiter with Aerorover Mission (TOAM)

    NASA Technical Reports Server (NTRS)

    Sittler, E. C., Jr.; Cooper, J. F.; Mahaffy, P.; Esper, J.; Fairbrother, D.; Farley, R.; Pitman, J.; Kojiro, D. R.; Acuna, M.; Allen, M.; Bjoraker, G.; Brasunas, J.; Farrell, W.; Burchell, M. J.; Burger, M.; Chin, G.; Coates, A. J.; Farrell, W.; Flasar, M.; Gerlach, B.; Gorevan, S.; Hartle, R. E.; Im, Eastwood; Jennings, D.; Johnson, R. E.

    2007-01-01

    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. One could also use aerobraking to put spacecraft into orbit around Saturn first for an Enceladus phase of the mission and then later use aerocapture to put spacecraft into orbit around Titan. The Aerorover will probably use a hot air balloon concept using the waste heat from the MMRTG approx. 1000 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. Distinguishing primary and secondary inclusion assemblages in Jack Hills zircons

    NASA Astrophysics Data System (ADS)

    Bell, Elizabeth A.; Boehnke, Patrick; Hopkins-Wielicki, Michelle D.; Harrison, T. Mark

    2015-10-01

    Detrital igneous zircons from Jack Hills, Western Australia, range in age from ~ 3.0 to nearly 4.4 Ga and contain an inclusion assemblage dominated by quartz and muscovite, cited as evidence of their derivation from peraluminous granitoids. However, some phosphate inclusions in these zircons are known to be secondary from their post-depositional U-Pb ages and manifest mineralization along cracks. We undertook a survey of mineral inclusions in 4.3-3.0 Ga Jack Hills zircons with particular emphasis on their relationship to possible alteration features (e.g., cracks, disturbed internal zonation, and visual turbidity). Mineral inclusions revealed at polished surfaces show variations in modal mineralogy, mostly corresponding to their relationship with cracks. Muscovite is common both on and away from cracks, although the chemistry of muscovite inclusions shows little relationship with other potential alteration features. Inclusions filling cracks (secondary) and inclusions isolated from cracks differ in their modal mineralogy, although both suites are rich in muscovite and quartz. The higher incidence of crack-intersecting inclusions among younger zircons may reflect effects of the (generally larger) inclusion size among younger zircons. Mismatches between the isolated and crack-intersecting populations indicate selective loss of certain phases (e.g., feldspar, apatite) and over-representation of quartz and muscovite along cracks likely due to the effects of larger inclusion size and varying degrees of overpressure following zircon cooling and decompression. Inclusions not associated with cracks in magmatically zoned versus regions with disturbed zoning have similar phase proportions. This indicates only minor inclusion replacement away from cracks (i.e., the isolated assemblage is likely primary). This holds true also for inclusions within visually turbid versus clear volumes of zircon. Phase proportions within the inclusion assemblages differ with age indicating a provenance shift toward fewer mafic phases and apatite in < 3.6 Ga relative to Hadean granitoid sources.

  9. Fabrication of zircon for disposition of weapons plutonium

    SciTech Connect

    Kim, K.C.; Huang, J.Y.; Serrano, P.L.

    1997-07-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). In an effort to address the problems of long term storage and nuclear waste minimization, zircon has been proposed as a host medium for plutonium and other actinides recovered from dismantled nuclear weapons. The objective of this work is to investigate the feasibility of large scale fabrication of Pu-bearing zircon. Since PuO{sub 2} is thermodynamically less stable than ZrO{sub 2}, it is expected that the process parameters determined for synthesizing ZrSiO{sub 4} (zircon) would be applicable to those for PuSiO{sub 4} (Pu-zircon). Furthermore, since the foremost concern in plutonium processing is the potential for contamination release, this work emphasizes the development of process parameters, using zircon first, to anticipate potential material problems in the containment system for reaction mixtures during processing. Stoichiometric mixtures of ZrO{sub 2} and SiO{sub 2}, in hundred-gram batches, have been subjected to hot isostatic pressing (HIP) at temperatures near 1,500 C and pressures approximately 10,000 psi. The product materials have been analyzed by x-ray powder diffraction, and are found to consist of zircon after approximately two hours of reaction time. From this work, it is clear that the fabrication of large quantities of Pu-zircon is feasible. The most notable result of this work is evidence for the existence of container problems. This result, in turn, suggests potential solutions to these problems. Experiments with the quartz inner container, the glass sealant, a sacrificial metal barrier, and a metal outer container are being investigated to mitigate these potential hazards.

  10. A Stress-Dependent Hysteresis Model for PZT-Based Transducers

    E-print Network

    . For temperatures above the Curie temperature Tc, the structure of PbTiO3 is cubic whereas for T ) (b) Figure 1. (a) High temperature paraelectric cubic form of lead titanate, and (b) low temperature

  11. Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites

    NASA Astrophysics Data System (ADS)

    Breiter, Karel; Lamarão, Claudio Nery; Borges, Régis Munhoz Krás; Dall'Agnol, Roberto

    2014-04-01

    The trace element content in zircons from A-type granites and rhyolites was investigated by using back-scattered electron images and electron microprobe analyses. The studied Proterozoic (Wiborg batholith, Finland and Pará, Amazonas and Goiás states, Brazil) and Variscan (Krušné Hory/Erzgebirge, Czech Republic and Germany) plutons cover a wide range of rocks, from large rapakivi-textured geochemically primitive plutons to small intrusions of F-, Li-, Sn-, Nb-, Ta-, and U-enriched rare-metal granites. While zircon is one of the first crystallized minerals in less fractionated metaluminous and peraluminous granites, it is a late-crystallized phase in peralkaline granites and in evolved granites that may crystallize during the whole process of magma solidification. The early crystals are included in mica, quartz, and feldspar; the late grains are included in fluorite or cryolite or are interstitial. The zircon in hornblende-biotite and biotite granites from the non-mineralized plutons is poor in minor and trace elements; the zircon in moderately fractionated granite varieties is slightly enriched in Hf, Th, U, Y, and HREEs; whereas the zircon in highly fractionated ore-bearing granites may be strongly enriched in Hf (up to 10 wt.% HfO2), Th (up to 10 wt.% ThO2), U (up to 10 wt.% UO2), Y (up to 12 wt.% Y2O3), Sc (up to 3 wt.% Sc2O3), Nb (up to 5 wt.% Nb2O5), Ta (up to 1 wt.% Ta2O5), W (up to 3 wt.% WO3), F (up to 2.5 wt.% F), P (up to 11 wt.% P2O5), and As (up to 1 wt.% As2O5). Metamictized zircons may also be enriched in Bi, Ca, Fe, and Al. The increase in the Hf content coupled with the decrease in the Zr/Hf value in zircon is one of the most reliable indicators of granitic magma evolution. In the zircon of A-type granites, the Zr/Hf value decreases from 41-67 (porphyritic granite) to 16-19 (equigranular granite) in the Kymi stock, Finland, and from 49-52 (biotite granite) to 18-36 (leucogranite) in the Pedra Branca pluton, Brazil. In the in situ strongly fractionated Cínovec cupola (Erzgebirge), the Zr/Hf value decreases from 33-51 in the protolithionite granite at a depth of 1255 m to 7.5-25 in the zinnwaldite granite at a depth of 40 m. At the scale of individual crystals, the Zr/Hf value decreases from 86 to 68 from the cores to the rims of the zircons from the Teplice rhyolite and from 64 to 33 in the zircons from the biotite granite at Krupka, Erzgebirge. The contents of Hf and U in zircon are dependent mainly on the degree of granite fractionation and the nature and volume of the volatile phases and are independent of the A- or S-character of the parental melt. The zircon Zr/Hf ratios 55 and 25 are proposed to approximately distinguish common, moderately evolved and highly evolved granites. Zircons from the moderately and highly evolved granites of A- and S-type can be discriminated on the basis of their HREE content and the U/Th ratios. Nb, Ta, and W are present in zircon from the highly evolved granites from all studied areas, while high As, Bi, and Sc contents are typical only for the Erzgebirge.

  12. Active control of bending vibrations in thick bars using PZT stack actuators

    SciTech Connect

    Redmond, J.; Parker, G.; Barney, P.; Rodeman, R.

    1995-07-01

    An experimental investigation into active control of bending vibrations in thick bar and plate-like structural elements is described. This work is motivated by vibration problems in machine tools and photolithography machines that require greater control authority than available from conventional surface mounted PZT patches or PVDF films. Focus of this experiment is a cantilevered circular steel bar in which PZT stacks are mounted in cutouts near the bar root. Axially aligned and offset from the neutral axis, these actuators control the bending vibrations by generating moments in the bar through their compressive loads. A Positive Feedback control law is used to significantly augment the damping in the first bending mode. Implications of the experimental results for machine tool stability enhancement are discussed.

  13. MECHANICAL STRAIN AND PIEZOELECTRIC PROPERTIES OF PZT STACKS RELATED TO SEMI-BIPOLAR ELECTRIC CYCLING FATIGUE

    SciTech Connect

    Wang, Hong; Lin, Hua-Tay; Wereszczak, Andrew A; Cooper, Thomas A

    2009-01-01

    PZT stacks that had an inter-digital internal electrode configuration and consisted of a specific number of multilayer actuators were tested to more than 108 cycles by using a 100-Hz semi-bipolar sine wave with a field range of +4.5/-0.9 kV/mm and a 20-MPa mechanical preload. Significant reductions in mechanical strain and piezoelectric coefficients were observed during the fatigue cycling, depending on the measuring condition. Extensive surface discharges and arcs were also observed. These surface events as well as related dielectric breakdown resulted in the erosion of external electrode and outcrop of internal electrode, and that partially accounts for the reduction observed above. The data obtained in this study demonstrated the feasibility of using a semi-bipolar mode to drive a PZT stack with a designed mechanical preload applied and illustrated the potential fatigue of stack~{!/~}s performance during its service.

  14. Fluid Vessel Quantity Using Non-invasive PZT Technology Flight Volume Measurements Under Zero G Analysis

    NASA Technical Reports Server (NTRS)

    Garofalo, Anthony A

    2013-01-01

    The purpose of the project is to perform analysis of data using the Systems Engineering Educational Discovery (SEED) program data from 2011 and 2012 Fluid Vessel Quantity using Non-Invasive PZT Technology flight volume measurements under Zero G conditions (parabolic Plane flight data). Also experimental planning and lab work for future sub-orbital experiments to use the NASA PZT technology for fluid volume measurement. Along with conducting data analysis of flight data, I also did a variety of other tasks. I provided the lab with detailed technical drawings, experimented with 3d printers, made changes to the liquid nitrogen skid schematics, and learned how to weld. I also programmed microcontrollers to interact with various sensors and helped with other things going on around the lab.

  15. One-step firing for electroded PZT thick films applied to MEMS

    NASA Astrophysics Data System (ADS)

    Debéda, H.; Clément, P.; Llobet, E.; Lucat, C.

    2015-02-01

    Free-standing electroded piezoelectric thick-films are straightforwardly fabricated thanks to the association of the low-cost screen-printing technology to the sacrificial layer method. After subsequent printing and drying of a stack of sacrificial, Au, PZT and Au layers on an alumina substrate, the final firing is performed at 900 °C. Then, the partial or total releasing step of the Au/PZT/Au is achieved in a diluted acidic solution. Bridges (3.3 × 3.3 × 0.080 mm3) and cantilevers (8 × 2 × 0.09 mm3) are directly attached to the alumina substrate on top of which they are processed. Studies of the electromechanical behavior of these components show the influence of both the releasing and the densification processes on the piezoelectric properties of the final component. Cantilevers fabricated with this method exhibit favourable properties for sensing applications.

  16. Fluid Vessel Quantity using Non-Invasive PZT Technology Flight Volume Measurements Under Zero G Analysis

    NASA Technical Reports Server (NTRS)

    Garofalo, Anthony A.

    2013-01-01

    The purpose of the project is to perform analysis of data using the Systems Engineering Educational Discovery (SEED) program data from 2011 and 2012 Fluid Vessel Quantity using Non-Invasive PZT Technology flight volume measurements under Zero G conditions (parabolic Plane flight data). Also experimental planning and lab work for future sub-orbital experiments to use the NASA PZT technology for fluid volume measurement. Along with conducting data analysis of flight data, I also did a variety of other tasks. I provided the lab with detailed technical drawings, experimented with 3d printers, made changes to the liquid nitrogen skid schematics, and learned how to weld. I also programmed microcontrollers to interact with various sensors and helped with other things going on around the lab.

  17. Nitrogen Chemistry in Titan's Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Kammer, J. A.; Shemansky, D. E.; Zhang, X.; Yung, Y. L.

    2012-04-01

    Titan’s atmosphere has evolved over time into its current state through complex photochemical processes (Yung et al. 1984), involving nitrogen (N2), the dominant molecular species in the atmosphere, as well as methane (CH4). It has been proposed that this composition may be analogous to the early Earth’s, as it certainly provides an abundance of hydrocarbons the like from which early life may have arisen (Coustenis & Taylor 1999; Lunine 2005). Recent results from the Cassini spacecraft have greatly improved our knowledge of the current state of Titan’s atmosphere, and measurements made by the Ultraviolet Imaging Spectrograph (UVIS) in particular are able to probe the region of interest from 400 km to 1500 km in altitude where much of the photochemistry on Titan occurs (Shemansky et al. 2005, Koskinen et al. 2011). This photochemistry in part converts nitrogen from stable N2 molecules and incorporates it into detectable hydrocarbon products such as HCN, HC3N, and other heavier compounds. Therefore the nitrogen story is of particular interest, and we examine UVIS occultation observations in both the EUV and FUV regions of the spectrum in order to directly retrieve the vertical profiles of N2 in addition to its related hydrocarbon derivatives. Constraints from UVIS on temperature profiles of the upper atmosphere are also examined and compared to current results from the Ion and Neutral Mass Spectrometer (INMS), which probes a region above 1000 km altitude in Titan’s atmosphere (Westlake et al. 2011). References: Coustenis, A., and F. Taylor: “Titan: The Earth-Like Moon”. Singapore: World Scientific, 1999. Koskinen, T. T., et al.: “The mesosphere and thermosphere of Titan revealed by Cassini/UVIS stellar occultations”. Icarus, Vol. 216, pp. 507-534, 2011. Lunine, J. I.: “Astrobiology: A Multidisciplinary Approach”. San Francisco, CA: Pearson Addison Wesley, 2005. Shemansky, D. E., et al.: “The Cassini UVIS stellar probe of the Titan atmosphere”. Science, Vol. 308, pp. 978-982, 2005. Westlake, J. H., et al.: “Titan’s thermospheric response to various plasma environments”. J. Geophys. Res., Vol. 116, A03318, 2011. Yung, Y. L., et al.: “Photochemistry of the atmosphere of Titan: Comparison between model and observations”. Astrophys. J., Suppl. Ser., Vol. 55, pp. 465-506, 1984.

  18. Spacecraft Exploration of Titan and Enceladus

    NASA Astrophysics Data System (ADS)

    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 TSSM were developed by a Joint Science Definition Team (JSDT). In the TSSM study the orbiter was assumed to be NASA’s responsibility while the in situ elements were assumed to be provided by ESA. The engineering and flight operations aspects were developed in a collaborative study by NASA and ESA engineering teams. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The European part was conducted in ESA within the Cosmic Vision 1 plan. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

  19. Aerosol growth in Titan's ionosphere.

    PubMed

    Lavvas, Panayotis; Yelle, Roger V; Koskinen, Tommi; Bazin, Axel; Vuitton, Véronique; Vigren, Erik; Galand, Marina; Wellbrock, Anne; Coates, Andrew J; Wahlund, Jan-Erik; Crary, Frank J; Snowden, Darci

    2013-02-19

    Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere. PMID:23382231

  20. Developing Zircon as a Probe of Planetary Impact History

    NASA Astrophysics Data System (ADS)

    Wielicki, Matthew

    2014-12-01

    The identification of Meteor Crater in Arizona as an extraterrestrial impact by Eugene Shoemaker provided the first evidence of this geologic phenomenon and opened the door to a new field of research that has eventually lead to the identification of over ~150 terrestrial impact structures. Subsequently impacts have been evoked in the formation of the moon, delivery of volatiles and bio-precursors to early Earth, creation of habitats for the earliest life and, in more recent times, major mass extinction events. However, understanding the impact flux to the Earth-Moon system has been complicated by the constant weathering and erosion at Earth's surface and the complex nature of impactite samples such that only a hand full of terrestrial craters have been accurately and precisely dated. Currently 40Ar/39Ar step-heating analysis of impactite samples is commonly used to infer impact ages but can be problematic due to the presence of relic clasts, incomplete 40Ar outgassing or excess 40Ar, and recoil and shock effects. The work presented here attempts to develop zircon geochronology to probe planetary impact histories as an alternative to current methods and provides another tool by which to constrain the bolide flux to the Earth-Moon system. Zircon has become the premier geo-chronometer in earth science and geochemical investigation of Hadean zircon from Western Australia has challenged the long-standing, popular conception that the near-surface Hadean Earth was an uninhabitable and hellish world; Zircons may preserve environmental information regarding their formation and thus provide a rare window into conditions on early Earth. Isotopic and petrologic analyses of these ancient grains have been interpreted to suggest that early Earth was more habitable than previously envisioned, with water oceans, continental crust, and possibly even plate tectonics. The Hadean is also suspected to be a time of major planetary bombardment however identifying impact signatures within the Hadean population remains difficult and this study hopes to develop criteria to recognize impact zircon and possibly provide constraints on the early impactor flux. Five large terrestrial craters, Vredefort and Morokweng, South Africa, Sudbury and Manicouagan, Canada, and Popigai, Russia, are the focus of this study as smaller craters do not have the energy to produce thick melt sheets, which persist over time-scales sufficient for crystallization of zircon, permitting geochemical and geochronological analysis. Geochemical analysis of these impact-produced zircons yields similar chemical signatures to endogenic igneous zircon from crustal melts and highlights the need for well-developed criteria for discriminating impact and endogenic grains for impact geochronology. One such criterion is modeling of impact zircon crystallization temperature spectra for simulated impact events on targets of varying composition. Provided some assumptions the zircon crystallization spectra can be estimated from well established Zr systematics in crustal melts. Results for impacts into an Archean terrestrial surface (used as a proxy for the Hadean as little to no rock record exists >4.0 Ga) yields a crystallization spectra significantly higher than that reported for the Hadean zircon population and appears to rule out impacts as a dominant source for these ancient grains. When no dateable impact melt sheet exists, either due to the lack of energy of the impact itself or from subsequent erosion at Earth's surface, loss of radiogenic lead, Pb*, has been suggested as an alternative method to date the event. Pb*-loss was investigated from target rocks from Vredefort and Morokweng and suggests that Pb* diffusion, even in zircon isolated from shocked and brecciated target rocks, is remarkably slow. This may explain the seeming lack of 'reset' zircon in terrestrial impactites. Little is known about Pb* diffusion pathways associated with shock microstructures introduced during impact cratering and future diffusion studies may provide better constraints on this problem. Although li

  1. Author's personal copy Metamorphic zircon, trace elements and Neoarchean metamorphism in the

    E-print Network

    Mojzsis, Stephen J.

    Author's personal copy Metamorphic zircon, trace elements and Neoarchean metamorphism in the ca. 3: R.L. Rudnick Keywords: Eoarchean Nuvvuagittuq Metamorphism Zircon Geochronology Quebec to show that Neoarchean metamorphism in the belt reached upper amphibolite facies conditions (~640 °C

  2. Piezoelectric response of a PZT thin film to magnetic fields from permanent magnet and coil combination

    NASA Astrophysics Data System (ADS)

    Guiffard, B.; Seveno, R.

    2015-01-01

    In this study, we report the magnetically induced electric field E 3 in Pb(Zr0.57Ti0.43)O3 (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude B ac at 45 kHz) and static magnetic induction ( B dc) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to B dc——is achieved for the thin film with largest effective electrode. This magnetoelectric (ME) effect is interpreted in terms of coupling between eddy current-induced Lorentz forces (stress) in the electrodes of PZT and piezoelectricity. Such coupling was evidenced by convenient modelling of experimental variations of electric field magnitude with both B ac and B dc induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E 3 versus B dc could also be modelled. At last, the results show that similar to multilayered piezoelectric-magnetostrictive composite film, a PZT thin film made with a simple manufacturing process can behave as a static or dynamic magnetic field sensor. In this latter case, a large ME voltage coefficient of under B dc = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems.

  3. An experimental investigation on PZT behavior under mechanical and cycling loading

    NASA Astrophysics Data System (ADS)

    Abramovich, Haim; Tsikchotsky, Eugeny; Klein, Gregory

    2013-11-01

    The drive to produce electrical energy by directly compressing piezoceramic material using mechanical stress stands behind the present test series. To be able to correctly choose the right material, PZT disks manufactured by three different manufacturers have been tested under static mechanical compressive and cyclic loads. It was shown that although the disks can withstand high mechanical stresses (up to 100 MPa) without any visible damage, their transduction is confined to much lower stresses (50-75 MPa), a range in which the electrical output is a function of the square of the applied stress. This range is further reduced, when the PZT is subjected to cyclic mechanical loading, yielding an applicable mechanical stress in the range of 30-40 MPa, from which electrical power can be produced without further deterioration. To compensate for the low electric power, due to relatively low mechanical stresses applied on the PZT disks, one can increase the volume of the material used by placing layers of piezoelectric material one on top of the other, each subjected to the same mechanical stress. This will yield the required electric power from a safe given mechanical stress without reduction in its output.

  4. Chemistry and evolution of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Strobel, D. F.

    1982-01-01

    The chemistry and evolution of Titan's atmosphere are reviewed, in light of the scientific findings from the Voyager mission. It is argued that the present N2 atmosphere may be Titan's initial atmosphere, rather than one photochemically derived from an original NH3 atmosphere. The escape rate of hydrogen from Titan is controlled by photochemical production from hydrocarbons. CH4 is irreversibly converted to less hydrogen-rich hydrocarbons, which over geologic time accumulate on the surface to a layer thickness of about 0.5 km. Magnetospheric electrons interacting with Titan's exosphere may dissociate enough N2 into hot, escaping N atoms to remove about 0.2 of Titan's present atmosphere over geologic time. The energy dissipation of magnetospheric electrons exceeds solar EUV 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.

  5. Transient clouds in Titan's lower atmosphere.

    PubMed

    Griffith, C A; Owen, T; Miller, G A; Geballe, T

    1998-10-01

    The 1980 encounter by the Voyager 1 spacecraft with Titan, Saturn's largest moon, revealed the presence of a thick atmosphere containing nitrogen and methane (1.4 and approximately 0.05 bar, respectively). Methane was found to be nearly saturated at Titan's tropopause, which, with other considerations, led to the hypothesis that Titan might experience a methane analogue of Earth's vigorous hydrological cycle, with clouds, rain and seas. Yet recent analyses of Voyager data indicate large areas of super-saturated methane, more indicative of dry and stagnant conditions. A resolution to this apparent contradiction requires observations of Titan's lower atmosphere, which was hidden from the Voyager cameras by the photochemical haze (or smog) in Titan's stratosphere. Here we report near-infrared spectroscopic observations of Titan within four narrow spectral windows where the moon's atmosphere is ostensibly transparent. We detect pronounced flux enhancements that indicate the presence of reflective methane condensation clouds in the troposphere. These clouds occur at a relatively low altitude (15+/-10 km), at low latitudes, and appear to cover approximately 9 per cent of Titan's disk. PMID:9783583

  6. Chemical investigation of Titan and Triton tholins

    NASA Technical Reports Server (NTRS)

    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.

  7. Geomorphology of Afekan Crater, Titan: Terrain Relationships in Titan’s Blandlands

    NASA Astrophysics Data System (ADS)

    Malaska, Michael; Shoenfeld, Ashley M.; Lopes, Rosaly M.; Hayes, Alex G.; Le Gall, Alice; Birch, Sam; Solomonidou, Anezina; Neish, Catherine D.; Soderblom, Jason M.; Farr, Thomas G.

    2014-11-01

    The enigmatic mid-latitude undifferentiated plains of Saturn’s moon Titan cover an estimated 29% of the surface of that world, making them one of the most important terrain units. Nicknamed “blandlands”, they appear nearly featureless to the Cassini spacecraft’s Visual and Infrared Mapping Spectrometer (VIMS), Imaging Science Subsystems (ISS) and Synthetic Aperture Radar (SAR) imaging. The possible origins and identity of the vast undifferentiated plains have ranged from thick organic photochemical deposits to cryovolcanic flood deposits of aqueous materials. To help constrain these possibilities, we selected the region around Afekan Crater for detailed geomorphological mapping. We defined and determined terrain units in ArcGIS primarily using SAR images and used the resulting contact and embayment relationships to determine a preliminary stratigraphy between the previously known units and the undifferentiated plains.We find that although the plains are relatively featureless, they are not flat - some topographic variation is observed. Our work suggests Titan’s dunes embay the undifferentiated plains. This is consistent with dunes actively invading and depositing in the topographically low regions of the undifferentiated plains. Correlation of our defined undifferentiated plains regions with radiometric data is not consistent with large exposures of putative water-based cryovolcanic outflows, but is consistent with dune materials. The infrared reflectance obtained by Cassini VIMS and ISS show distinctive albedo differences between the dunes and undifferentiated plains materials. Combined, these results provide support that the undifferentiated plains are composed of organic materials, but that they are distinct from unmodified dune materials. Undifferentiated plains are found partially filling the interior of Afekan Crater, as well as in the presumed wind shadow of Afekan Crater, implying that plains material deposition happened after Afekan Crater was formed. Channels and other fluvial features are not abundant in the Afekan region at 300 m resolution, we interpret this to imply that the undifferentiated plains are porous, or that they only support sub-resolution channels and fluvial features.

  8. Strontium Titanate DC Electric Field Switchable and Tunable Bulk Acoustic Wave Solidly Mounted Resonator

    E-print Network

    York, Robert A.

    Strontium Titanate DC Electric Field Switchable and Tunable Bulk Acoustic Wave Solidly Mounted Abstract - A voltage switchable/tunable strontium titanate solidly mounted BAW resonator was implemented films, piezoelectric resonators. I. INTRODUCTION Strontium titanate (STO) and barium strontium titanate

  9. Titan's emission processes during eclipse

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; West, R. A.; Gronoff, G.; Rannou, P.

    2014-10-01

    Observations of Titan's emissions during its 2009 eclipse by Saturn revealed a weak airglow around the moon, as well as a brighter emission from its disk (West et al. [2012]. Geophys. Res. Lett. 39 (1), 18204). We explore here the potential mechanisms that could generate these emissions and more specifically the role of magnetospheric plasma and cosmic rays in the upper and lower atmosphere, respectively. We consider excitation of N2 by these energy sources and calculate the resulting emissions through a detailed model of N2 airglow followed by careful radiation transfer of the emitted photons through the atmosphere, and into the UVIS and ISS instruments. Our results indicate that the observed limb emissions are consistent with magnetospheric plasma energy input, while emissions instigated by cosmic ray excitation are very weak and cannot explain the observed disk emissions. We discuss possible contributions from other sources that could potentially explain the disk observations. The most likely scenario is that of scattered stellar light from Titan's disk.

  10. The greenhouse and antigreenhouse effects on Titan

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Planetary science. The weather on Titan.

    PubMed

    Lorenz, R D

    2000-10-20

    When the Voyager 1 spacecraft returned images in 1980, the dense atmosphere of Saturn's moon Titan was assumed to be bland and featureless. As Lorenz discusses in his Perspective, recent ground-based spectroscopy, and images from the Hubble Space Telescope, are changing this perception. Observations such as the short-lived clouds in Titan's atmosphere reported by Griffith et al. suggest that although average precipitation is likely to be low, individual precipitation events may be heavy enough to cause deep valleys on Titan's surface. PMID:11183770

  13. Growth of Zircone on Nanoporous Alumina Using Molecular Layer Deposition

    NASA Astrophysics Data System (ADS)

    Hall, Robert A.; George, Steven M.; Kim, Yeongae; Hwang, Woonbong; Samberg, Meghan E.; Monteiro-Riviere, Nancy A.; Narayan, Roger J.

    2014-04-01

    Molecular layer deposition (MLD) is a sequential and self-limiting process that may be used to create hybrid organic/inorganic thin films from organometallic precursors and organic alcohol precursors. In this study, films of a zirconium-containing hybrid organic/inorganic polymer known as zircone were grown on nanoporous alumina using MLD. Scanning electron microscopy data showed obliteration of the pores in zircone-coated nanoporous alumina. An in vitro cell viability study indicated that the growth of human epidermal keratinocytes was the greatest on zircone-coated nanoporous alumina than on uncoated nanoporous alumina. Our results suggest that MLD may be used to create biocompatible coatings for use in many types of medical devices.

  14. Milling assisted synthesis of calcium zirconate ??Zr?3

    NASA Astrophysics Data System (ADS)

    Kalinkin, A. M.; Nevedomskii, V. N.; Kalinkina, E. V.; Balyakin, K. V.

    2014-08-01

    Monophase calcium zirconate (CaZrO3) has been prepared from the equimolar ZrO2 + CaCO3 mixture by two-step synthesis process. In the first step, mechanical treatment of the mixture is performed in an AGO-2 planetary ball mill. In the second step, the milled mixture is annealed to form calcium zirconate. High-energy ball milling of the (ZrO2+CaCO3) mixture results in decrease in the temperature of CaZrO3 formation during annealing at 950 °C. The enhancement of CaZrO3 synthesis is due to accumulation of excess energy by the reagents, decreasing the particle size and notable increase in the interphase area because of “smearing” of CaCO3 on ZrO2 particles during milling. Nanocrystalline calcium zirconate has been produced by controlling the annealing temperature and time.

  15. Synthesis of Single-Crystalline Perovskite Nanorods Composed of Barium Titanate and Strontium Titanate

    E-print Network

    Walsworth, Ronald L.

    Synthesis of Single-Crystalline Perovskite Nanorods Composed of Barium Titanate and Strontium alkoxide precursors and 1 mmol of oleic acid (Aldrich, 99+%). The precursors, barium titanium isopropoxide

  16. Zircon-scale insights into the history of a Supervolcano, Bishop Tuff, Long Valley, California, with implications for the Ti-in-zircon geothermometer

    NASA Astrophysics Data System (ADS)

    Reid, Mary R.; Vazquez, Jorge A.; Schmitt, Axel K.

    2011-02-01

    Zircon has the outstanding capacity to record chronological, thermal, and chemical information, including the storage history of zoned silicic magma reservoirs like the one responsible for the Bishop Tuff of eastern California, USA. Our novel ion microprobe approach reveals that Bishop zircon rims with diverse chemical characteristics surround intermediate domains with broadly similar compositions. The highest Y, REE, U, and Th concentrations tend to accompany the largest excesses in Y + REE3+:P beyond what can be explained by xenotime substitution in zircon. Apparent Ti-in-zircon temperatures of <720°C for zircon rims are distinctly lower than most of the range in eruption temperatures, as estimated from FeTi-oxide equilibria and zircon solubility at quench. While permissive of crystallization of zircon at near-solidus conditions, the low Ti-in-zircon temperatures are probably better explained by sources of inaccuracy in the temperature estimates. After apparently nucleating from different melts, zircons from across the Bishop Tuff compositional spectrum may have evolved to broadly similar chemical and thermal conditions and therefore it is possible that there was no significant thermal gradient in the magma reservoir at some stage in its evolution. There is also no compelling evidence for punctuated heat ± chemical influxes during the intermediate stages of zircon growth. Judging by the zircon record, the main volume of the erupted magma evolved normally by secular cooling but the latest erupted portion is characterized by a reversal in chemistry that appears to indicate perfusion of the magma reservoir by—or zircon entrainment in—a less evolved melt from the one in which the zircons had previously resided.

  17. Zircon-scale insights into the history of a Supervolcano, Bishop Tuff, Long Valley, California, with implications for the Ti-in-zircon geothermometer

    USGS Publications Warehouse

    Reid, M.R.; Vazquez, J.A.; Schmitt, A.K.

    2011-01-01

    Zircon has the outstanding capacity to record chronological, thermal, and chemical information, including the storage history of zoned silicic magma reservoirs like the one responsible for the Bishop Tuff of eastern California, USA. Our novel ion microprobe approach reveals that Bishop zircon rims with diverse chemical characteristics surround intermediate domains with broadly similar compositions. The highest Y, REE, U, and Th concentrations tend to accompany the largest excesses in Y + REE3+:P beyond what can be explained by xenotime substitution in zircon. Apparent Ti-in-zircon temperatures of <720??C for zircon rims are distinctly lower than most of the range in eruption temperatures, as estimated from FeTi-oxide equilibria and zircon solubility at quench. While permissive of crystallization of zircon at near-solidus conditions, the low Ti-in-zircon temperatures are probably better explained by sources of inaccuracy in the temperature estimates. After apparently nucleating from different melts, zircons from across the Bishop Tuff compositional spectrum may have evolved to broadly similar chemical and thermal conditions and therefore it is possible that there was no significant thermal gradient in the magma reservoir at some stage in its evolution. There is also no compelling evidence for punctuated heat ?? chemical influxes during the intermediate stages of zircon growth. Judging by the zircon record, the main volume of the erupted magma evolved normally by secular cooling but the latest erupted portion is characterized by a reversal in chemistry that appears to indicate perfusion of the magma reservoir by-or zircon entrainment in-a less evolved melt from the one in which the zircons had previously resided. ?? 2010 Springer-Verlag.

  18. Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO

    E-print Network

    Haile, Sossina M.

    Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO Peter Babilo and Sossina M properties of doped barium zirconate have been examined. With the use of zinc ox- ide as a sintering aid, Ba of the material under flowing CO2 showed ZnO-modified barium zirconate to exhibit excellent chemical stability

  19. Titan's Magic Island: Transient features in a Titan sea

    NASA Astrophysics Data System (ADS)

    Hofgartner, J. D.; Hayes, A. G., Jr.; Lunine, J. I.; Zebker, H. A.; Stiles, B. W.; Sotin, C.; Barnes, J. W.; Turtle, E. P.; Baines, K. H.; Brown, R. H.; Buratti, B. J.; Clark, R. N.; Encrenaz, P.; Kirk, R. L.; Le Gall, A. A.; Lopes, R. M. C.; Lorenz, R. D.; Malaska, M. J.; Mitchell, K. L.; Nicholson, P. D.; Paillou, P.; Radebaugh, J.; Wall, S. D.; Wood, C. A.

    2014-12-01

    Transient bright features, popularly referred to as Titan's Magic Island, were observed in Cassini Synthetic Aperture Radar (SAR) images of the northern sea, Ligeia Mare, in July 2013 (Hofgartner et al., 2014, Nature Geosci. 7, 493). Images obtained prior and subsequent to the July 2013 detection do not include these bright features. The features are not consistent with ambiguities, scalloping, gain control or edge effects and are not considered to be standard SAR image artifacts. We compared the measured radar cross-sections from the region of the anomalies to a suite of quasi-specular plus diffuse backscatter models and found that this class of models for a permanent structure can be ruled out to 88% confidence. Thus we conclude that the appearance of the features is the result of a transformation and the subsequent non-detections indicate that they were transient. The observational constraints do not permit tides and/or sea level change to be the dominant cause of the transient expression. We suggest that ephemeral phenomena such as surface waves, rising bubbles, and suspended or floating solids best explain these features. Local meteorology could stimulate or enhance these phenomena, but we are unable to constrain its role in the appearance of these transients. These enigmatic features and the waves reportedly detected in Punga Mare (Barnes et al., 2014, Planetary Science, accepted) are likely the first glimpses of dynamic processes that are commencing in the northern lakes and seas as summer nears in the northern hemisphere. It is plausible that they are an expression of the changing seasons and as Titan's northern hemisphere continues transitioning toward summer they may occur with increased frequency. Ligeia Mare, including the region of the transients, will be observed again during the Cassini Titan flyby on August 21, 2014 and this observation could be diagnostic of the nature of these features. For example, if the transients are waves and waves are detectable at the 12 degrees incidence of the upcoming radar measurements, the predicted increase in wind speeds should result in a higher spatial density of these features.

  20. Molecular dynamics modelling of radiation damage in zircon

    NASA Astrophysics Data System (ADS)

    Grechanovsky, A. E.

    2009-04-01

    Zircon (ZrSiO4) is among actinide-bearing phases which has been proposed as a crystalline confinement matrix for nuclear waste management, especially for weapon-grade plutonium and UO2 spent fuel in the USA. Zircon is also widely used in geochronology. But, with accumulating ?-decay damage, zircon undergoes a radiation induced transition to an amorphous (or metamict) state. So, in the present work molecular dynamics simulations (MD simulations) of zircon structure have been performed to study radiation damage in zircon. In this technique, one simulates the propagation of an energetic particle in a system of atoms interacting via model potentials, by integrating the Newton equations of motion. Author has used version 3.09 of the DL_POLY molecular simulation package. Zircon structure containing 181944 atoms (19x19x21 unit cells) was equilibrated at 300 K for 10 ps, and one Zr atom (usually called the primary knock-on atom, PKA) was given a velocity corresponding to an implantation energy of about 20 keV. MD simulations were performed in the microcanonical ensemble that is under conditions of constant particle number, volume and energy. Results of the MD simulations show that the number of interstitials is equal to 840 atoms. This is very close (4000-5000 atoms for 70 keV recoil atom 234Th) to what is measured in the diffuse x-ray scattering and NMR experiments on amorphous metamict samples (damaged by natural irradiation) of geological age. It has been shown that the damaged structure contains several depleted regions with characteristic sized up to 2,5 nm after single event and up to 4,5 nm after three overlapping events. Furthermore, these events produce channels of depleted matter between the overlapping damaged regions. These channels provide a high-diffusivity path for radiogenic Pb (percolation effect). Loss of radiogenic Pb may result in to incorrect dating of rocks.

  1. Differential helium retention in zircons: Implications for nuclear waste containment

    NASA Astrophysics Data System (ADS)

    Gentry, Robert V.; Glish, Gary L.; McBay, Eddy H.

    A very sensitive helium leak detector was utilized to measure the helium liberated from groups of zircons extracted from six deep granite cores. The observed low differential loss of gaseous helium down to 2900 m (197°C) in these ancient Precambrian rocks is easily attributable to the greater diffusion of He at higher temperatures rather than losses due to corrosion of the zircons. This fact strongly suggests that deep granite burial should be a very safe corrosion-resistant containment procedure for long-term waste encapsulation.

  2. Cassini: Mission to Saturn and Titan

    NASA Technical Reports Server (NTRS)

    Kerridge, Stuart J.; Flury, Walter; Horn, Linda J.; Lebreton, Jean-Pierre; Stetson, Douglas S.; Stoller, Richard L.; Tan, Grace H.

    1992-01-01

    The Cassini Mission to Saturn and Titan represents an important step into the exploration of the outerplanets. It will expand on the flyby encounters of Pioneer and Voyager and parallel the detailed exploration of the Jupiter system to be accomplished by the Galileo Mission. By continuing the study of the two giant planets and enabling detailed comparisons of their structure and behavior, Cassini will provide a tremendous insight into the formation and evolution of the solar system. In addition, by virtue of its focus on the Saturnian satellite Titan, Cassini will return detailed data on an environment whose atmospheric chemistry may resemble that of the primitive Earth. The scientific objectives can be divided into five categories: Titan, Saturn, rings, icy satellites, and magnetospheres. The key area of interest to exobiologists is Titan; the other four scientific categories will be discussed briefly to provide a comprehensive overview of the Cassini Mission.

  3. Cassini RADAR: 10 years at Titan

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2014-04-01

    Cassini has turned Titan from a variegated orb into a dynamic world of exotic and yet also familiar landscapes. The Cassini RADAR investigation has been instrumental in that transformation. Here I review the highlights of how that process unfolded.

  4. Synthesis and characterization of new cystalline titanates 

    E-print Network

    Nge, Renita

    1994-01-01

    measurements, thermal gravimetric analysis and differential thermal analysis. By swelling and pillaring, the interlayer distance was increased up to 2.6 nm prior to calcination at 500 'C. Although pillaring the titanates, by employing n...

  5. Anomolous Radar Backscatter from Titan's Xanadu

    NASA Astrophysics Data System (ADS)

    Janssen, M. A.; Le Gall, A.; Wye, L. C.; Zebker, H. A.; Lorenz, R. D.; Paillou, P.; Paganelli, F.; Cassini RADAR Team

    2009-03-01

    We use simultaneously measured radar reflectivity and microwave emission from the Cassini Radar instrument to show that the radar backscattering seen across Titan's Xanadu region is too high to be explained by any known surface model.

  6. Prebiotic-like chemistry on Titan.

    PubMed

    Raulin, François; Brassé, Coralie; Poch, Olivier; Coll, Patrice

    2012-08-21

    Titan, the largest satellite of Saturn, is the only one in the solar system with a dense atmosphere. Mainly composed of dinitrogen with several % of methane, this atmosphere experiences complex organic processes, both in the gas and aerosol phases, which are of prebiotic interest and within an environment of astrobiological interest. This tutorial review presents the different approaches which can be followed to study such an exotic place and its chemistry: observation, theoretical modeling and experimental simulation. It describes the Cassini-Huygens mission, as an example of observational tools, and gives the new astrobiologically oriented vision of Titan which is now available by coupling the three approaches. This includes the many analogies between Titan and the Earth, in spite of the much lower temperature in the Saturn system, the complex organic chemistry in the atmosphere, from the gas to the aerosol phases, but also the potential organic chemistry on Titan's surface, and in its possible internal water ocean. PMID:22481630

  7. The thermal structure of Titan’s upper atmosphere, I: Temperature profiles from Cassini INMS observations

    NASA Astrophysics Data System (ADS)

    Snowden, D.; Yelle, R. V.; Cui, J.; Wahlund, J.-E.; Edberg, N. J. T.; Ågren, K.

    2013-09-01

    We derive vertical temperature profiles from Ion Neutral Mass Spectrometer (INMS) N2 density measurements from 32 Cassini passes. We find that the average temperature of Titan’s thermosphere varies significantly from pass-to-pass between 112 and 175 K. The temperatures from individual temperature profiles also varies considerably, with many passes exhibiting wave-like temperature perturbations and large temperature gradients. Wave-like temperature perturbations have wavelengths between 150 and 420 km and amplitudes between 3% and 22% and vertical wave power spectra of the INMS data and HASI data have a slope between -2 and -3, which is consistent with vertically propagating atmospheric waves. The lack of a strong correlation between temperature and latitude, longitude, solar zenith angle, or local solar time indicates that the thermal structure of Titan’s thermosphere is not primarily determined by the absorption of solar EUV flux. At N2 densities greater than 108 cm-3, Titan’s thermosphere is colder when Titan is observed in Saturn’s magnetospheric lobes compared to Saturn’s plasma sheet as proposed by Westlake et al. (Westlake, J.H. et al. [2011]. J. Geophys. Res. 116, A03318. http://dx.doi.org/10.1029/2010JA016251). This apparent correlation suggests that magnetospheric particle precipitation causes the temperature variability in Titan’s thermosphere; however, at densities smaller than 108 cm-3 the lobe passes are hotter than the plasma sheet passes and we find no correlation between the temperature of Titan’s thermosphere and ionospheric signatures of enhanced particle precipitation, which suggests that the correlation is not indicative of a physical connection. The temperature of Titan’s thermosphere also may have decreased by ?10 K around mid-2007. Finally, we classify the vertical temperature profiles to show which passes are hot and cold and which passes have the largest temperature variations. In a companion paper (Part II), we estimate the strength of energy sources and sinks in Titan’s thermosphere.

  8. Titan's Atmospheric Dynamics and Meteorology

    NASA Technical Reports Server (NTRS)

    Flasar, F. M.; Baines, K. H.; Bird, M. K.; Tokano, T.; West, R. A.

    2008-01-01

    Titan, after Venus, is the second example of an atmosphere with a global cyclostrophic circulation in the solar system, but a circulation that has a strong seasonal modulation in the middle atmosphere. Direct measurement of Titan's winds, particularly observations tracking the Huygens probe at 10degS, indicate that the zonal winds are generally in the sense of the satellites rotation. They become cyclostrophic approx. 35 km above the surface and generally increase with altitude, with the exception of a sharp minimum centered near 75 km, where the wind velocity decreases to nearly zero. Zonal winds derived from the temperature field retrieved from Cassini measurements, using the thermal wind equation, indicate a strong winter circumpolar vortex, with maximum winds at mid northern latitudes of 190 ms-' near 300 km. Above this level, the vortex decays. Curiously, the zonal winds and temperatures are symmetric about a pole that is offset from the surface pole by approx.4 degrees. The cause of this is not well understood, but it may reflect the response of a cyclostrophic circulation to the offset between the equator, where the distance to the rotation axis is greatest, and the solar equator. The mean meridional circulation can be inferred from the temperature field and the meridional distribution of organic molecules and condensates and hazes. Both the warm temperatures in the north polar region near 400 km and the enhanced concentration of several organic molecules suggests subsidence there during winter and early spring. Stratospheric condensates are localized at high northern latitudes, with a sharp cut-off near 50degN. Titan's winter polar vortex appears to share many of the same characteristics of winter vortices on Earth-the ozone holes. Global mapping of temperatures, winds, and composition in he troposphere, by contrast, is incomplete. The few suitable discrete clouds that have bee found for tracking indicate smaller velocities than aloft, consistent with the Huygens measurements. At low latitudes the zonal winds near the surface appear not to be westward as on Earth, but eastward. Because the net zonal-mean time-averaged torq exerted by the surface on the atmosphere should vanish, this implies westward flow o part of the surface; the question is where. The latitude contrast in tropospheric temperatures, deduced from radio occultations at low, mid, and high latitudes, is small approx.5 K at the tropopause and approx.3 K at the surface.

  9. Corona discharge of Titan's troposphere

    NASA Astrophysics Data System (ADS)

    Navarro-González, Rafael; Ramírez, Sandra I.

    1997-05-01

    The atmosphere of Titan is constantly bombarded by galactic cosmic rays and Saturnian magnetospheric electrons causing the formation of free electrons and primary ions, which are then stabilized by ion cluster formation and charging of aerosols. These charged particles accumulate in drops in cloud regions of the troposphere. Their abundance can substantially increase by friction, fragmentation or collisions during convective activity. Charge separation occurs with help of convection and gravitational settling leading to development of electric fields within the cloud and between the cloud and the ground. Neutralization of these charge particles leads to corona discharges which are characterized by low current densities. These electric discharges could induce a number of chemical reactions in the troposphere and hence it is of interest to explore such effects. We have therefore, experimentally studied the corona discharge of a simulated Titan's atmosphere (10% methane and 2% argon in nitrogen) at 500 Torr and 298 K by GC-FTIR-MS techniques. The main products have been identified as hydrocarbons (ethane, ethyne, ethene, propane, propene + propyne, cyclopropane, butane, 2-methylpropane, 2-methylpropene, n-butene, 2-butene, 2,2-dimethylpropane, 2-methylbutane, 2-methylbutene, n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, n-hexane, 2,2-dimethylhexane, 2,2-dimethylpentane, 2,2,3-trimethylbutane, 2,3-dimethylpentane and n-heptane), nitriles (hydrogen cyanide, cyanogen, ethanenitrile, propanenitrile, 2-methylpropanenitrile and butanenitrile) and an uncharacterized film deposit. We present their trends of formation as a function of discharge time in an ample interval and have derived their initial yields of formation. These results clearly demonstrate that a complex organic chemistry can be initiated by corona processes in the lower atmosphere. Although photochemistry and charged particle chemistry occurring in the stratosphere can account for many of the observed hydrocarbon species in Titan, the predicted abundance of ethene is to low by a factor of 10 to 40. While some ethene will be produced by charged-particle chemistry, its production by corona processes and subsequent diffusion into the stratosphere appears to be an adequate source. Because little UV penetrates to the lower atmosphere to destroy the molecules formed there, the corona-produced species may be long-lived and contribute significantly to the composition of the lower atmosphere and surface.

  10. Future Exploration of Titan and Enceladus

    NASA Astrophysics Data System (ADS)

    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 Team (JSDT). The orbiter was NASA's responsibility while the in situ elements were designed by ESA. The engineering and flight operations aspects of TSSM were developed in a collaborative study, conducted by NASA and ESA engineering teams working on both sides of the Atlantic. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The European part was conducted in ESA within the Cosmic Vision 1 plan. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

  11. Energy Deposition Processes in Titan's Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Sittler, Edward C., Jr.; Bertucci, Cesar; Coates, Andrew; Cravens, Tom; Dandouras, Iannis; Shemansky, Don

    2008-01-01

    Most of Titan's atmospheric organic and nitrogen chemistry, aerosol formation, and atmospheric loss are driven from external energy sources such as Solar UV, Saturn's magnetosphere, solar wind and galactic cosmic rays. The Solar UV tends to dominate the energy input at lower altitudes of approximately 1100 km but which can extend down to approximately 400 km, while the plasma interaction from Saturn's magnetosphere, Saturn's magnetosheath or solar wind are more important at higher altitudes of approximately 1400 km, but the heavy ion plasma [O(+)] of approximately 2 keV and energetic ions [H(+)] of approximately 30 keV or higher from Saturn's magnetosphere can penetrate below 950km. Cosmic rays with energies of greater than 1 GeV can penetrate much deeper into Titan's atmosphere with most of its energy deposited at approximately 100 km altitude. The haze layer tends to dominate between 100 km and 300 km. The induced magnetic field from Titan's interaction with the external plasma can be very complex and will tend to channel the flow of energy into Titan's upper atmosphere. Cassini observations combined with advanced hybrid simulations of the plasma interaction with Titan's upper atmosphere show significant changes in the character of the interaction with Saturn local time at Titan's orbit where the magnetosphere displays large and systematic changes with local time. The external solar wind can also drive sub-storms within the magnetosphere which can then modify the magnetospheric interaction with Titan. Another important parameter is solar zenith angle (SZA) with respect to the co-rotation direction of the magnetospheric flow. Titan's interaction can contribute to atmospheric loss via pickup ion loss, scavenging of Titan's ionospheric plasma, loss of ionospheric plasma down its induced magnetotail via an ionospheric wind, and non-thermal loss of the atmosphere via heating and sputtering induced by the bombardment of magnetospheric keV ions and electrons. This energy input evidently drives the large positive and negative ions observed below approximately 1100 km altitude with ion masses exceeding 10,000 daltons. We refer to these ions as seed particles for the aerosols observed below 300 km altitude. These seed particles can be formed, for example, from the polymerization of acetylene (C2H2) and benzene (C6H6) molecules in Titan's upper atmosphere to form polycyclic aromatic hydrocarbons (PAH) and/or fullerenes (C60). In the case of fullerenes, which are hollow spherical carbon shells, magnetospheric keV [O(+)] ions can become trapped inside the fullerenes and eventually find themselves inside the aerosols as free oxygen. The aerosols are then expected to fall to Titan's surface as polymerized hydrocarbons with trapped free oxygen where unknown surface chemistry can take place.

  12. Titan's Length-of-Day Variations

    NASA Astrophysics Data System (ADS)

    Folonier, Hugo Alberto; Ferraz-Mello, Sylvio

    2015-11-01

    The Cassini radar observation of Titan over several years show that the rotation period is slightly faster than the synchronous motion (Lorenz et al. 2008; Stiles et al. 2008 and 2011; Meriggiola 2012). The seasonal variation in the mean and zonal wind speed and direction in Titan’s lower troposphere causes the exchange of a substantial amount of angular momentum between the surface and the atmosphere (Tokano and Neubauer, 2005; Richard et al. 2014). The rotation variation is affected by the influence of the atmosphere when we assume that Titan is a differentiated body and the atmosphere interacts only with the outer layer.In this work, we calculate variations of Titan’s length-of-day when the body is formed by two independent rotating parts and assuming that friction occurs at the interface of them. The tides are considered using the extension of two different theories -- the Darwin tide theory and Ferraz-Mello’s creep tide theory -- to the case of one body formed by two homogeneous parts. The results are compared and their differences are discussed.

  13. An Analysis of Titan's Tropical Clouds

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin; Penteado, Paulo; Le Mouelic, Stéphane

    2008-09-01

    For the past 8 years, methane clouds have appeared primarily within 30 degrees of the south pole, and in a band centered at 40S latitude, where updrafts are predicted in Titan's circulation. The association of clouds with rising circulation branches is also seen on Earth. But unlike Earth, Titan's circulation is expected to change dramatically with season, with the roughly pole-to-pole circulation flipping such that rising branches occur in the summer hemisphere. Titan is currently approaching equinox, which will occur in 2010. Ground-based and Cassini observations indicate an increasingly greater prevalence of clouds in Titan's tropical atmosphere. These clouds are of interest not only because they are newcomers, and may manifest seasonal variations in Titan's atmosphere, but also because they occur very close to the Huygens landing site, where the methane and temperature profiles have been determined. Here we discuss radiative transfer derivation of the structure of Titan's tropical clouds, detected from VIMS observations, in concert with the structural information of the atmosphere, determined from Huygens observations, to understand the clouds' origins.

  14. Titan's ion chemistry: a laboratory perspective.

    PubMed

    McEwan, Murray J; Anicich, Vincent G

    2007-01-01

    Some of the most interesting objects in the solar system are those bodies that have significant atmospheres. The discovery that Titan, Saturn's largest satellite, has a substantial nitrogen-based atmosphere makes it a prime extraterrestrial object of interest. The advent of the Cassini orbiter spacecraft program that is able to observe and sample Titan's ionosphere adds greatly to this interest. We report here a summary of some of the efforts that have been made in the laboratory to understand the processes responsible for chemical processing of the primary ions formed in Titan's ionosphere, into the ions observed by in situ sampling. The presence of significant hydrocarbons and the colder temperatures of Titan's ionosphere lead to a much greater complexity in the ion chemistry of Titan than is apparent in the ion chemistry of Earth. A review of all the ion-molecule chemistry investigated in laboratory studies relevant to Titan is included as a table. The complexity of some of the hydrocarbon ion structures formed in just three reactive ion-molecule sequences from the primary ions has required a new experimental methodology which is discussed. PMID:17216629

  15. A facility for simulating Titan's environment

    NASA Astrophysics Data System (ADS)

    Wasiak, F. C.; Luspay-Kuti, A.; Welivitiya, W. D. D. P.; Roe, L. A.; Chevrier, V. F.; Blackburn, D. G.; Cornet, T.

    2013-04-01

    As a result of measurements acquired by the Cassini-Huygens mission of Titan's near surface atmospheric composition and temperature, Titan conditions can now be simulated in the laboratory and samples can subsequently be subjected to those conditions. Titan demonstrates an active hydrological-like cycle with its thick atmosphere, dynamic clouds, polar lakes of methane and ethane, moist regolith, and extensive fluvial erosive features. Unlike Earth, Titan's hydrological-like cycle likely involves several constituents, primarily methane and ethane. Here the properties of a new Titan simulation facility are presented, including conceptual methodology, design, implementation, and performance results. The chamber maintains Titan's surface temperature and pressure, and the sample cryogenic liquids undergoing experimentation are condensed within the chamber itself. During the experiments, the evaporation rates of the sample liquids are directly determined by continually measuring mass. Constituents are analyzed utilizing a Fourier Transform Infrared Spectroscopy (FTIR), and vapor concentrations are determined using a gas chromatograph fitted with a Flame Ionization Detector (FID). All pertinent data is logged via computer. Under laboratory conditions, the direct measurements of the evaporation rates of methane, ethane, and mixtures thereof can be achieved. Among the processes to be studied are the effects of regolith on transport from the subsurface to the atmosphere, the freezing point depression effects of dissolved nitrogen, and the solubility of various relevant organic compounds.

  16. Impact Craters on Titan? Cassini RADAR View

    NASA Technical Reports Server (NTRS)

    Wood, Charles A.; Lopes, Rosaly; Stofan, Ellen R.; Paganelli, Flora; Elachi, Charles

    2005-01-01

    Titan is a planet-size (diameter of 5,150 km) satellite of Saturn that is currently being investigated by the Cassini spacecraft. Thus far only one flyby (Oct. 26, 2004; Ta) has occurred when radar images were obtained. In February, 2005, and approximately 20 more times in the next four years, additional radar swaths will be acquired. Each full swath images about 1% of Titan s surface at 13.78 GHz (Ku-band) with a maximum resolution of 400 m. The Ta radar pass [1] demonstrated that Titan has a solid surface with multiple types of landforms. However, there is no compelling detection of impact craters in this first radar swath. Dione, Tethys and other satellites of Saturn are intensely cratered, there is no way that Titan could have escaped a similar impact cratering past; thus there must be ongoing dynamic surface processes that erase impact craters (and other landforms) on Titan. The surface of Titan must be very young and the resurfacing rate must be significantly higher than the impact cratering rate.

  17. The Lakes and Seas of Titan

    NASA Astrophysics Data System (ADS)

    Lopes, Rosaly M. C.; Mitchell, Karl L.; Wall, Stephen D.; Mitri, Giuseppe; Janssen, Michael; Ostro, Steven; Kirk, Randolph L.; Hayes, Alexander G.; Stofan, Ellen R.; Lunine, Jonathan I.; Lorenz, Ralph D.; Wood, Charles; Radebaugh, Jani; Paillou, Philippe; Zebker, H.; Paganelli, Flora

    2007-12-01

    The study of Titan, Saturn's largest satellite, is a major goal of the Cassini-Huygens mission. This joint project between NASA, the European Space Agency, and the Italian Space Agency consists of a Saturn orbiter (Cassini) and a Titan probe (Huygens). Since the mission's arrival at Saturn in July 2004, one of its most spectacular discoveries has been the finding of the first extraterrestrial nonmagmatic standing bodies of liquid: Titan's hydrocarbon lakes and seas. In July 2006, the first synthetic aperture radar (SAR) images of Titan's north polar region btained by the Cassini spacecraft showed dozens of lakes above latitudes of 70° [Stofan et al., 2007]. Subsequent SAR images obtained by Cassini have covered approximately 68% of Titan's north polar region at latitudes above 60 degrees. These images show more than 400 radar-dark areas that we interpret as being liquid lakes (shown in dark blue in Figure 1), including a few that are so large that they rightfully may be called seas. We discuss here the evidence for liquids on Titan, the distribution and morphology of lakes, and recent data that indicate the presence of lakes in the south polar regions.

  18. Performance of PIN-PMN-PT Single Crystal Piezoelectric versus PZT8 Piezoceramic Materials in Ultrasonic Transducers

    NASA Astrophysics Data System (ADS)

    DeAngelis, D. A.; Schulze, G. W.

    The recent advancements in the manufacturing of single crystal PIN-PMN-PT piezoelectric materials now make them a cost-competitive alternative to PZT4 and PZT8 (Navy Types I and III) piezoceramic materials, which have been the workhorse of power ultrasonic applications (e.g., welding, cutting, sonar, etc.) for over 50 years. Although there are great benefits to the use of single crystal materials with respect to high output, as well as added actuating and sensing abilities, many transducer designers are still reluctant to explore these materials due to inadequate design guidelines for substituting the familiar PZT materials; for example, what are the implications of the higher capacitance, sensitivity to chipping/cracks, aging effects, frequency shifts, or how much preload can be used are all common questions. This research is a case study on the performance of identical ultrasonic transducer bodies, used for semiconductor wire bonding, assembled with either PZT8 or PIN-PMN-PT piezo material. The main purpose of the study is to establish rule-of-thumb design guidelines for direct substitution of single crystal materials in existing PZT8 transducer designs, along with a side-by-side performance comparison to highlight benefits. Several metrics are investigated such as impedance, frequency, displacement gain, quality factor and electromechanical coupling factor.

  19. Enhanced off-resonance magnetoelectric response in laser annealed PZT thick film grown on magnetostrictive amorphous metal substrate

    NASA Astrophysics Data System (ADS)

    Palneedi, Haribabu; Maurya, Deepam; Kim, Gi-Yeop; Priya, Shashank; Kang, Suk-Joong L.; Kim, Kwang-Ho; Choi, Si-Young; Ryu, Jungho

    2015-07-01

    A highly dense, 4 ?m-thick Pb(Zr,Ti)O3 (PZT) film is deposited on amorphous magnetostrictive Metglas foil (FeBSi) by granule spray in vacuum process at room temperature, followed by its localized annealing with a continuous-wave 560 nm ytterbium fiber laser radiation. This longer-wavelength laser radiation is able to anneal the whole of thick PZT film layer without any deteriorative effects, such as chemical reaction and/or atomic diffusion, at the interface and crystallization of amorphous Metglas substrate. Greatly enhanced dielectric and ferroelectric properties of the annealed PZT are attributed to its better crystallinity and grain growth induced by laser irradiation. As a result, a colossal off-resonance magnetoelectric (ME) voltage coefficient that is two orders of magnitude larger than previously reported output from PZT/Metglas film-composites is achieved. The present work addresses the problems involved in the fabrication of PZT/Metglas film-composites and opens up emerging possibilities in employing piezoelectric materials with low thermal budget substrates (suitable for integrated electronics) and designing laminate composites for ME based devices.

  20. Parallel contingency statistics with Titan.

    SciTech Connect

    Thompson, David C.; Pebay, Philippe Pierre

    2009-09-01

    This report summarizes existing statistical engines in VTK/Titan and presents the recently parallelized contingency statistics engine. It is a sequel to [PT08] and [BPRT09] which studied the parallel descriptive, correlative, multi-correlative, and principal component analysis engines. The ease of use of this new parallel engines is illustrated by the means of C++ code snippets. Furthermore, this report justifies the design of these engines with parallel scalability in mind; however, the very nature of contingency tables prevent this new engine from exhibiting optimal parallel speed-up as the aforementioned engines do. This report therefore discusses the design trade-offs we made and study performance with up to 200 processors.

  1. Field-induced strain behavior for potassium sodium bismuth titanate ceramics.

    PubMed

    Carroll, James F; Payne, David A; Noguchi, Yuji; Miyayama, Masaru

    2007-12-01

    Data are reported for the dielectric, piezoelectric, electrostrictive, and ferroelectric properties of potassium-substituted sodium bismuth titanate, [(K(x)Na(1-x))(0.5)Bi(0.5)]TiO3. For the morphotropic phase boundary composition x = 0.2, relaxor-type behavior was observed at room temperature with piezoelectric (effective d(333) = 325 x 10(-12) m/V) and ferroelectric properties (P(R) = 25 microC/cm(2), E(C) = 30 kV/cm). A transition to a relatively frequency-independent, diffuse phase transformation region occurred with increasing temperature, with no remanent strain or coercive field. Above the transition temperature, the field-induced strain was consistent with contributions from electrostriction and field induced piezoelectricity (M(3333) = 1.9 x 10(-16) m2/V2 and d333 = 81 x 10(-12) m/V at 100 degrees C). Information is given for the temperature dependence of properties, e.g., 0.14% strain induced at 50 kV/cm at 200 degrees C. Higher potassium content x = 0.6 stabilized the ferroelectric piezoelectric region to temperatures above 200 degrees C, with a relatively stable d(333) = 150-145 x 10-12 m/V between 25 degrees C and 200 degrees C. Pb-free KNBT ceramics appear competitive with PZT, especially for higher temperature electromechanical applications. PMID:18276548

  2. Geologic Conditions Required for the Fluvial Erosion of Titan’s Craters

    NASA Astrophysics Data System (ADS)

    Kinser, Rebeca; Neish, Catherine; Howard, Alan; Schenk, Paul; Bray, Veronica

    2015-11-01

    In comparison to other icy satellites, Titan has a small number of impact craters on its surface. This suggests that it has a young surface and/or erosional processes that remove craters from its surface. The set of geological conditions on Titan that would allow craters to become unrecognizable by orbiting spacecraft such as Cassini is unclear. Initial results suggest that not all geologic conditions would allow for complete degradation of impact craters on Titan. Using a landscape evolution model, we explored a larger parameter space to determine the conditions under which a representative 40 km crater on Titan would be eroded. We focused on varying the values of parameters such as bedrock and regolith erodibility, sediment grain size, the weathering rate of the regolith, and whether or not the regolith was saturated with liquid hydrocarbons. We found that only after changing the saturation state of the regolith mid-way through the simulation was it possible to completely erode the crater. Since there are few craters on Titan, this suggests that during Titan’s geological history there may have been varying quantities of liquid on its surface. Titan is known to have a dense atmosphere, not unlike that of the Earth, that could allow for surface liquids to vary under a changing climate. The erosion rate could then also vary as a direct result of changing climatic conditions.

  3. Dissolution on Titan and on Earth: Toward the age of Titan's karstic landscapes

    NASA Astrophysics Data System (ADS)

    Cornet, Thomas; Cordier, Daniel; Bahers, Tangui Le; Bourgeois, Olivier; Fleurant, Cyril; Mouélic, Stéphane Le; Altobelli, Nicolas

    2015-06-01

    Titan's polar surface is dotted with hundreds of lacustrine depressions. Based on the hypothesis that they are karstic in origin, we aim at determining the efficiency of surface dissolution as a landshaping process on Titan, in a comparative planetology perspective with the Earth as reference. Our approach is based on the calculation of solutional denudation rates and allow inference of formation timescales for topographic depressions developed by chemical erosion on both planetary bodies. The model depends on the solubility of solids in liquids, the density of solids and liquids, and the average annual net rainfall rates. We compute and compare the denudation rates of pure solid organics in liquid hydrocarbons and of minerals in liquid water over Titan and Earth timescales. We then investigate the denudation rates of a superficial organic layer in liquid methane over one Titan year. At this timescale, such a layer on Titan would behave like salts or carbonates on Earth depending on its composition, which means that dissolution processes would likely occur but would be 30 times slower on Titan compared to the Earth due to the seasonality of precipitation. Assuming an average depth of 100 m for Titan's lacustrine depressions, these could have developed in a few tens of millions of years at polar latitudes higher than 70°N and S, and a few hundreds of million years at lower polar latitudes. The ages determined are consistent with the youth of the surface (<1 Gyr) and the repartition of dissolution-related landforms on Titan.

  4. Rare earth elements in synthetic zircon. 1. synthesis, and rare earth element and phosphorus doping.

    SciTech Connect

    Hanchar, J. M.; Finch, R. J.; Hoskin, W. O.; Watson, E. B.; Cherniak, D. J.; Mariano, A. N.; Chemical Engineering; George Washington Univ.; Univ. of Canterbury; Australian National Univ.; Rensselaer Polytechnic Inst.

    2001-05-01

    Sedimentary mineral assemblages commonly contain detrital zircon crystals as part of the heavy-mineral fraction. Age spectra determined by U-Pb isotopic analysis of single zircon crystals within a sample may directly image the age composition--but not the chemical composition--of the source region. Rare earth element (REE) abundances have been measured for zircons from a range of common crustal igneous rock types from different tectonic environments, as well as kimberlite, carbonatite, and high-grade metamorphic rocks, to assess the potential of using zircon REE characteristics to infer the rock types present in sediment source regions. Except for zircon with probable mantle affinities, zircon REE abundances and normalized patterns show little intersample and intrasample variation. To evaluate the actual variation in detrital zircon REE composition in a true sediment of known mixed provenance, zircons from a sandstone sample from the Statfjord Formation (North Sea) were analyzed. Despite a provenance including high-grade metasediment and granitoids and a range in zircon age of 2.82 b.y., the zircon REEs exhibit a narrow abundance range with no systematic differences in pattern shape. These evidences show zircon REE patterns and abundances are generally not useful as indicators of provenance.

  5. Is Titan's Dune Orientation Controlled by Tropical Methane Storms?

    NASA Astrophysics Data System (ADS)

    Charnay, Benjamin; Barth, Erika; Rafkin, Scot; Narteau, Clément; Lebonnois, Sébastien; Rodriguez, Sébastien; Courrech du Pont, Sylvain; Lucas, Antoine

    2014-11-01

    Titan’s equatorial regions are covered by eastward oriented linear dunes. This direction is opposite to mean surface winds simulated by Global Climate Models (GCMs) at these latitudes, oriented westward as trade winds on Earth [1, 2].Here, we propose that Titan’s dune orientation is actually determined by equinoctial tropical methane storms producing a coupling with superrotation and dune formation. Using meso-scale simulations of convective methane clouds [3, 4] with a GCM wind profile featuring the superrotation [5, 6], we show that Titan’s storms should produce fast eastward gust fronts above the surface. Such gusts dominate the aeolian transport. Using GCM wind roses and analogies with terrestrial dune fields [7], we show that Titan's dune growth occurs eastward under these conditions. Finally, this scenario combining global circulation winds and methane storms can explain other major features of Titan's dunes (i.e. divergence from the equator, size and spacing).References:[1] Lorenz et al.: The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes, Science (2006)[2] Lorenz & Radebaugh: Global pattern of Titan’s dunes: Radar survey from the Cassini prime mission, Geophysical Research Letter (2009)[3] Barth & Rafkin.: TRAMS: A new dynamic cloud model for Titan’s methane clouds, Geophysical Research Letter (2007)[4] Barth & Rafkin.: Convective cloud heights as a diagnostic for methane environment on Titan, Icarus (2010)[5] Charnay & Lebonnois: Two boundary layers in Titan's lower troposphere inferred from a climate model, Nature Geoscience (2012)[6] Lebonnois et al.: Titan global climate model: A new 3-dimensional version of the IPSL Titan GCM, Icarus (2012)[7] Courrech du Pont, Narteau & Gao: Two modes for dune orientation, Geology (2014)

  6. Ion irradiation effects in natural garnets: Comparison with zircon

    E-print Network

    Utsunomiya, Satoshi

    Ion irradiation effects in natural garnets: Comparison with zircon S. Utsunomiya, L.M. Wang, R ; Z ¼ 8) under ion-beam irradiation was investigated in order to compare its radiation susceptibility during the ion irradiation at high temperature. This behavior may be related to the phase relations

  7. HRTEM study of zircon from Eliseev anorthosite complex, Antarctica

    SciTech Connect

    Wirth, R.; Kaempf, H.; Hoehndorf, A.

    1996-12-31

    Zircon-bearing rocks of this study are metamorphic oxide-apatite gabbronorites (OAGN) from the Eliseev Anorthosite Complex, Wohlthat-Massif, East Antarctica. These unusual rocks are strongly enriched in accessory minerals apatite: <10 vol.%; zircon: < 1 vol.. Three steps in the evolution of these rocks are distinguished: a magnetic formation, followed by a granulite facies metamorphism and finally a tectonomagmatic overprint. The zircon crystals of this study are brown colored, up to 12 mm in length and up to 3 mm wide. Petrological investigations show that zircon has formed during the granulite facies event. Optical microscopy and cathodoluminiscence microscopy reveal a rhythmic zoning and many microcracks. The concentrations of uranium and thorium are low (U: 34-89 ppm and Th: 3-9 ppm). The radiation damage by radioactive decay of U and Th is expected to be minor due to the low uranium and thorium content. The investigations were carried out in a Philips CM200 transmission electron microscope. Analytical electron microscopy was performed by energy dispersive analysis (EDAX).

  8. Microanalysis of Hafnian Zircon Chi Ma and George R. Rossman

    E-print Network

    Ma, Chi

    in the famous Stewart pegmatite, Pala District, San Diego County, California. The Stewart mine, as part of the gem-bearing and rare- element-bearing granitic pegmatites in Southern California, has been mined of hafnian zircon, which may insight as to how the Stewart pegmatite and various pink tourmalines formed

  9. Raman study of radiation-damaged zircon under hydrostatic compression

    NASA Astrophysics Data System (ADS)

    Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

    2008-12-01

    Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ?3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

  10. Multiple Soft-Mode Vibrations of Lead Zirconate J. Hlinka,*

    E-print Network

    Ku?el, Petr

    lead zirconate single crystals have yielded a comprehensive picture of temperature vibrations of Pb ions and librations of oxygen octahedra. Their relation to phonon modes of the parent cubic two oxygen octahedra tilt modes. DOI: 10.1103/PhysRevLett.112.197601 PACS numbers: 77.80.-e, 63.20.D

  11. Micro-spectroscopic mapping: revealing internal structures of zircon crystals

    NASA Astrophysics Data System (ADS)

    Nasdala, L.; Reiners, P. W.; Hanchar, J. M.

    2003-04-01

    Natural zircon crystals typically deviate from perfect crystallinity and ideal chemical composition. If non-ideality features are not homogeneously distributed within a crystal but show a heterogeneity pattern, this is referred to as its "internal structure". Internal structures of zircon are mostly first caused by the heterogeneous incorporation of trace elements during crystal growth. Over time, these primary patterns may become more complex after being overprinted by radioactive self-irradiation and heterogeneous alteration or recrystallization. Internal structures may provide valuable information about the origin and post-growth history of zircon crystals. Further, they need to be recognized for sound microprobe dating, for instance to avoid biased results when straddling zones of different age. Revealing internal structures has thus become an important tool in zircon research. It is mostly done by means of backscattered electrons or cathodoluminescence imaging. These two techniques are advantageous over optical microscopy in the cross-polarized mode as the volume resolution is better and simple polished mounts instead of doubly-sided sections are needed. A disadvantage, however, is that the impact of electron beam during analysis causes local structural changes. Quantitative studies of the real structure of zircon samples, such as determination of the degree of the radiation damage, is therefore tainted with potential uncertainty when being done after electron probe analysis. As an alternative, we present images of internal zircon structures generated through visible laser excitation and mapping of the Raman and photoluminescence light. Due to the time-consuming mapping procedure, such images will perhaps not be routinely used. For detailed studies, however, they may provide most valuable information. Photoluminescence maps provide, for instance, information on both the distribution of rare earth elements (band integrals) and the short-range order (band broadening) whereas Raman-based images are most sensitive for revealing patterns of heterogeneous radiation damage. Application of micro-spectroscopic mappings to the study of zircon crystals from the Gold Butte block, Nevada, and the Adirondack Mountains, New York State, are presented.

  12. Chemical composition of Titan’s atmosphere and ionosphere: Observations and the photochemical model

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2014-07-01

    Basic observational data on hydrocarbons, nitriles, and ions on Titan are compared with predictions of the photochemical model. Uncertainties of the observed abundances and differences between the data from different instruments and observing teams are comparable with the differences between the observations and the model results. Main reactions of production and loss for each species are quantitatively assessed and briefly discussed. Formation of haze by polymerization of hydrocarbons and nitriles and recombination of heavy ions is calculated along with condensation of various species near the tropopause. Overall deposition is a layer of 300 m thick for the age of the Solar System, and nitrogen constitutes 8% of the deposition. The model reproduces the basic observational data and adequately describes basic chemical processes in Titan’s atmosphere and ionosphere. The presented model results and the observational data may be used as a reference to chemical composition of Titan’s atmosphere and ionosphere.

  13. Dissolution on Titan and on Earth: Towards the age of Titan's karstic landscapes

    E-print Network

    Cornet, Thomas; Bahers, Tangui Le; Bourgeois, Olivier; Fleurant, Cyril; Mouélic, Stéphane Le; Altobelli, Nicolas

    2015-01-01

    Titan's polar surface is dotted with hundreds of lacustrine depressions. Based on the hypothesis that they are karstic in origin, we aim at determining the efficiency of surface dissolution as a landshaping process on Titan, in a comparative planetology perspective with the Earth as reference. Our approach is based on the calculation of solutional denudation rates and allow inference of formation timescales for topographic depressions developed by chemical erosion on both planetary bodies. The model depends on the solubility of solids in liquids, the density of solids and liquids, and the average annual net rainfall rates. We compute and compare the denudation rates of pure solid organics in liquid hydrocarbons and of minerals in liquid water over Titan and Earth timescales. We then investigate the denudation rates of a superficial organic layer in liquid methane over one Titan year. At this timescale, such a layer on Titan would behave like salts or carbonates on Earth depending on its composition, which mea...

  14. A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

    2011-01-01

    Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (< 10(exp 4) pC/N). For instance, more than 80% of PEHT related papers are on transverse "31" mode cantilever beam type PEHTs (CBPEHTs) having piezoelectric coefficients of about 100 pC/N. The level of harvested electrical power for CBPEHTs is on the order of microW even at resonance mode. In order to harvest more electrical energy across broader bandwidth, high effective piezoelectric coefficient structures are needed. In this study, we investigate a "33" longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective piezoelectric coefficient structures enable PEHTs to harvest more electrical energy from mechanical vibrations or motions, suggesting an effective design for high-performance low-footprint PEHTs with potential applications in military, aerospace, and portable electronics. In addition, this study provides a route for using piezoelectric multilayer stacks for active or semi-active adaptive control to damp, harvest or transform unwanted dynamic vibrations into useful electrical energy.

  15. The Dynamics of Titan's Convective Clouds

    NASA Astrophysics Data System (ADS)

    Rafkin, S. C.

    2012-12-01

    Titan's deep convective clouds are the most dynamic phenomena known to operate within the atmosphere of the moon. Previous studies have focused primarily on the control of these storms by the large scale thermodynamic environment, especially methane abundance, which determines the amount of convective available potential energy (CAPE). This study looks at factors in addition to the thermodynamic environment that may have a first order impact on the evolution and structure of Titan's deep convective clouds. To the extent that thunderstorms on Earth provide a reasonable analog to the storms on Titan, it is well established that CAPE alone is insufficient to determine the structure and behavior of deep convection. Wind shear—both directional and speed—is also known to exert a first order effect. The influence of both CAPE and wind speed shear is typically expressed as the ratio of the two parameters in the form of the Bulk Richardson Number. On Earth, for a fixed value of CAPE, the addition of wind speed shear (i.e., the reduction of the Bulk Richardson Number) will tend to produce storms that are longer lived, tilted upshear with height, and multi-cellular in nature. These multi-cellular storms also tend to be more violent than storms generated in low wind speed shear environments: strong winds and large hail are common. The addition of directional shear (i.e., helicity) can transform the multi-cell storms into single, intense supercell storms. These are the storms associated typically associated with tornadoes. With respect to Titan, if there is a similar dependence on the Bulk Richardson Number, then this would have implications for how long Titan's storms live, how much precipitation they can produce, the area they cover, and the strength and duration of winds. A series of numerical simulations of Titan's deep convective clouds from the Titan Regional Atmospheric Modeling System are presented. A reasonable sweep of the parameter space of CAPE and shear for Titan is used to quantify the dependence of Titan's storms on the same parameters known to affect deep convection on Earth. The results of the simulations and the implications for Titan are then discussed.imulated convection in a calm (left) and wind shear environment (right). Cloud mixing ratio (g/kg) is shaded. Winds are indicated by vectors with a reference in the lower right of each panel.

  16. On the thermal electron balance in Titan’s sunlit upper atmosphere

    NASA Astrophysics Data System (ADS)

    Vigren, E.; Galand, M.; Yelle, R. V.; Cui, J.; Wahlund, J.-E.; Ågren, K.; Lavvas, P. P.; Mueller-Wodarg, I. C. F.; Strobel, D. F.; Vuitton, V.; Bazin, A.

    2013-03-01

    The Cassini mission has investigated Titan’s upper atmosphere in detail and found that, under solar irradiation, it has a well-developed ionosphere, which peaks between 1000 and 1200 km. In this paper we focus on the T40, T41, T42 and T48 Titan flybys by the Cassini spacecraft and use in situ measurements of N2 and CH4 densities by the Ion Neutral Mass Spectrometer (INMS) as input into a solar energy deposition model to determine electron production rates. We combine these electron production rates with estimates of the effective recombination coefficient based on available laboratory data for Titan ions’ dissociative recombination rates and electron temperatures derived from the Langmuir probe (LP) to predict electron number densities in Titan’s upper atmosphere, assuming photochemical equilibrium and loss of electrons exclusively through dissociative recombination with molecular ions. We then compare these predicted electron number densities with those observed in Titan’s upper atmosphere by the LP. The assumption of photochemical equilibrium is supported by a reasonable agreement between the altitudes where the electron densities are observed to peak and where the electron production rates are calculated to peak (roughly corresponding to the unit optical depth for HeII photons at 30.38 nm). We find, however, that the predicted electron number densities are nearly a factor of two higher than those observed throughout the altitude range between 1050 and 1200 km (where we have made estimates of the effective recombination coefficient). There are different possible reasons for this discrepancy; one possibility is that there may be important loss processes of free electrons other than dissociative recombination in Titan’s upper atmosphere.

  17. Using the VIMS Dataset to Understand Titan’s Hydrologic Cycle Through Cloud Characterization

    NASA Astrophysics Data System (ADS)

    Corlies, Paul; Hayes, Alexander G.; Rodriguez, Sebastien; Adamkovics, Mate; Rojo, Patricio; Turtle, Elizabeth P.

    2015-11-01

    Along with Earth, Titan is the only body in our Solar System to possess an active hydrologic cycle. Monitoring how Titan’s methane-based hydrologic cycle varies with season over Saturn’s 29.7-year orbital period is essential for understanding its climate system.Using a newly developed radiative transfer pipeline, with updated HITRAN methane line parameters, we will present an ongoing analysis of the known cloud observations in the VIMS dataset. Although much work has gone into finding clouds in this dataset, little work has been done on understanding the characteristics of these clouds, barring a handful of individual analyses. Our pipeline allows for fast determination of these cloud characteristics including optical depth, altitude, and mean drop size. VIMS offers two advantages: providing consecutive observations of individual cloud systems to help diagnose formation mechanism and providing a decade long dataset to track seasonal variations, like those observed in cloud frequency and location. Characterizing clouds allows for an understanding of seasonally varying formation mechanisms, traces Titan’s atmospheric methane content across seasonal timescales, and can indicate clouds that could potentially have precipitated to provide context for interpreting observed surface features.We will also present an update on an ongoing ground based- cloud monitoring campaign. This campaign, begun in April 2014, has (nearly) continually monitored Titan on a variety of telescopes for the past 1.5 years. To date, no cloud activity has been observed, despite the variety in observation techniques that multiple telescopes allow. This is interesting because large cloud outbursts were observed during the equivalent point in southern summer and suggest a dichotomy in the seasonal dynamics of Titan’s atmosphere. Understanding when and with what frequency clouds begin to form in the north is crucial to understanding Titan’s hydrologic cycle on seasonal time scales.

  18. Cassini RADAR's Third and Fourth Looks at Titan

    NASA Astrophysics Data System (ADS)

    Elachi, C.; Wall, S. D.; Allison, M. D.; Anderson, Y.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Franceschetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Janssen, M. A.; Johnson, W. T. K.; Kelleher, K.; Kirk, R. L.; Lopes, R. M.; Lorenz, R.; Lunine, J. I.; Muhleman, D. O.; Orosei, R.; Ostro, S. J.; Paganelli, F.; Picardi, G.; Posa, F.; Roth, L. E.; Seu, R.; Shaffer, S.; Soderblom, L. A.; Stiles, B.; Stofan, E.; Vetrella, S.; West, R.; Wood, C. A.; Wye, L.; Zebker, H.; Rizk, B.; McFarlane, L.

    2006-03-01

    The Cassini Titan RADAR Mapper has made two close passes of Titan's southern hemisphere in 2005, discovering extensive drainage channels, embayments, and broad areas of dark dunes. Together these emphasize the relative youthfulness of the surface.

  19. Innovative concepts for the Titan II space launch vehicle

    NASA Astrophysics Data System (ADS)

    French, Bruce M.

    1991-06-01

    A number of concepts that will enable Titan II to launch a greater spectrum of payloads is presented. The history of Titan development is outlined, and emphasis is placed on the development of the Titan II space launch vehicle (SLV) as well as on two types of missions contracted for the Titan II SLV. The current payload capabilities of the Titan II SLV are discussed, and attention is focused on a Titan II variant called the Titan IIS with a number of solid rocket motors added to the first stage, the Titan IIL employing liquid rocket boosters, and an enhanced attitude control system. A concept involving two small bipropellant engines on the aft end of stage II as well as a concept involving restarting of the stage-II main engine are considered.

  20. Titan IV - Latest in a family of giants

    NASA Astrophysics Data System (ADS)

    Hanley, Art

    1991-07-01

    An overview is presented of the origin and development of U.S. heavy-lift vehicles with particular focus on the Titan group of launchers. The Titan I ICBM first flew in 1959, to be followed by the growth II and III launchers to the present operational Titan IV. The most powerful unmanned rocket ever constructed in the West, Titan IV utilizes the same guidance system as Titan II space launch vehicles and Titan III series and comprises a liquid propellant two-stage core plus two solid propellant motors. Titan IV has the same capability to LEO as the Shuttle, 50,000 lb with the three-segment solid rocket motor upgrade. With inertial upper stage it can place 5100 lb in geosynchronous orbit. Consideration is given to the various launch complexes that are capable of handling Titan IV launches.

  1. Estimating erosional exhumation on Titan from drainage network morphology

    E-print Network

    Perron, J. Taylor

    Drainage networks on Titan, Earth, and Mars provide the only known examples of non-volcanic fluvial activity in our solar system. The drainage networks on Titan are apparently the result of a methane-ethane cycle similar ...

  2. Morphology of fluvial networks on Titan: Evidence for structural control

    E-print Network

    Burr, Devon M.

    Although Titan’s surface shows clear evidence of erosional modification, such as fluvial incision, evidence for tectonism has been less apparent. On Earth, fluvial networks with strongly preferred orientations are often ...

  3. Identification of cavitation signatures using both optical and PZT acoustic sensors

    NASA Astrophysics Data System (ADS)

    Vidakovic, M.; Armakolas, I.; Sun, T.; Carlton, J.; Grattan, K. T. V.

    2015-09-01

    This paper presents the results obtained from monitoring a simulated material cavitation process using both a fibre Bragg grating (FBG)-based acoustic sensor system developed at City University London and a commercial PZT (Piezoelectric Transducer) acoustic sensor, with an aim to identify the cavitation signatures. In the experiment, a sample metal plate with its back surface being instrumented with both sensors is positioned very close to an excitation sonotrode with a standard frequency of 19.5kHz. The data obtained from both sensors are recorded and analyzed, showing a very good agreement.

  4. Testing of an actively damped boring bar featuring structurally integrated PZT stack actuators

    SciTech Connect

    Redmond, J.; Barney, P.

    1998-06-01

    This paper summarizes the results of cutting tests performed using an actively damped boring bar to minimize chatter in metal cutting. A commercially available 2 inch diameter boring bar was modified to incorporate PZT stack actuators for controlling tool bending vibrations encountered during metal removal. The extensional motion of the actuators induce bending moments in the host structure through a two-point preloaded mounting scheme. Cutting tests performed at various speeds and depths of cuts on a hardened steel workpiece illustrate the bar`s effectiveness toward eliminating chatter vibrations and improving workpiece surface finish.

  5. Fabrication of microstructures in aviation components with a femtosecond laser based on PZT scanning

    NASA Astrophysics Data System (ADS)

    Yang, Xiaojun; Zhao, Wei; Li, Ming; Zhao, Hualong; Zhang, Huixing; Li, Peng; Yang, Yong; Cheng, Guanghua

    2013-05-01

    Thermal defects and low precision are the main disadvantages of fabricating micro-holes, irregular holes, and micro-slots in thermostable aviation materials. We demonstrate a manufacturing method employing a femtosecond laser and piezoelectric ceramic (PZT). The production process parameters were optimized according to the metallographic and dimensional accuracy of the microstructure, which was measured by phase-contrast microscopy and scanning electron microscopy. The limitations in a conventional aeroengine, such as in the recast layer, recrystallization, and micro-cracks, which degrade the performance and service life, were resolved with a simple, controllable, and commercial method.

  6. Influence of CO on Titan atmospheric reactivity

    NASA Astrophysics Data System (ADS)

    Fleury, B.; Carrasco, N.; Gautier, T.; Mahjoub, A.; He, J.; Szopa, C.; Buch, A.; Cernogora, G.

    2013-12-01

    The atmosphere of Titan is mainly composed of N2 and CH4, and photochemical volatiles products CxHyNz. Most of the laboratory studies simulating Titan's atmospheric reactivity focus on the highly complex carbon and nitrogen organic chemistry leading to a production of laboratory analogues of Titan's aerosols, called Tholins [Alcouffe et al., 2010]. However, the atmosphere of Titan also contains traces of oxygen compounds. The most abudant one detected is carbon monoxyde CO with a 47 ppmv concentration measured in high stratosphere [de Kok et al., 2007]. In this work we investigate the influence of CO on the N2-CH4 reactivity. We simulate the whole reaction chains with a laboratory Radio Frequency Capacitively Coupled plasma discharge (RF CCP) gas mixture of nitrogen, methane and carbon monoxyde. In order to detect unambiguously the possible effects, CO is introduced with amounts of 0 - 1 - 2.25 - 4.5 %, larger than in Titan's atmosphere. The kinetics of the methane is monitored by mass spectrometry and the compositions of the gas phase and tholins are monitored by GC-MS and elemental analysis respectively. We find that CO modifies the composition of the gas phase with the detection of oxygenated compounds. CO decreases drastically the production efficiency of tholins, involving also a perturbation on the methane kinetics. The oxygen incorporation in tholins is found to be efficient . As a conclusion, we show that carbon monoxyde is effectively coupled with N2-CH4 chemistry and that it impacts even the solid organic aerosols. References: Alcouffe, G., et al (2010), Capacitively coupled plasma used to simulate Titan's atmospheric chemistry, Plasma Sources Science and Technology, 19(1), 015008. de Kok, R., et al. (2007), Oxygen compounds in Titan's stratosphere as observed by Cassini CIRS, Icarus, 186(2), 354-363.

  7. Complex organics in Titan lakes: Spectral detection and Chemical behavior

    NASA Astrophysics Data System (ADS)

    Nna-Mvondo, D.; Singh, S.; Chevrier, V. F.; Tobie, G.; Mège, D.

    2015-10-01

    The chemical composition of Titan's lakes is still poorly determined. Liquid ethane and methane may be abundant with the presence of other organic species from atmospheric precipitation, such as complex organics similar to Titan tholins. Our study aims to examine how Titan tholins may interact with non-polar solvents (liquid methane, liquid ethane and their mixture) and if in such liquid medium their spectral identification is possible, in application to future exploration of Titan's lakes.

  8. Large aperture deformable mirror with a transferred single-crystal silicon membrane actuated using large-stroke PZT Unimorph Actuators

    NASA Technical Reports Server (NTRS)

    Hishinumat, Yoshikazu; Yang, Eui - Hyeok (EH)

    2005-01-01

    We have demonstrated a large aperture (50 mm x 50 mm) continuous membrane deformable mirror (DM) with a large-stroke piezoelectric unimorph actuator array. The DM consists of a continuous, large aperture, silicon membrane 'transferred' in its entirety onto a 20 x 20 piezoelectric unimorph actuator array. A PZT unimorph actuator, 2.5 mm in diameter with optimized PZT/Si thickness and design showed a deflection of 5.7 [m at 20V. An assembled DM showed an operating frequency bandwidth of 30 kHz and influence function of approximately 30%.

  9. saturn.jpl.nasa.gov Huygens at Titan

    E-print Network

    Withers, Paul

    saturn.jpl.nasa.gov #12;Huygens at Titan Paul Withers Boston University (withers@bu.edu) Titan-like geology? #12;saturn.jpl.nasa.gov #12;Teemu Makinen, FMI #12;photojournal.jpl.nasa.gov #12;photojournal) Science, 302, 403-404 #12;saturn.jpl.nasa.gov #12;Titan's Surface and Interior · Are or were liquids

  10. Ferroelectric Properties of Individual Barium Titanate Nanowires Investigated

    E-print Network

    Walsworth, Ronald L.

    Ferroelectric Properties of Individual Barium Titanate Nanowires Investigated by Scanned Probe on the ferroelectric properties of individual single-crystalline barium titanate nanowires. We show that nonvolatile report the scanned probe characterization of individual single-crystalline barium titanate (BaTiO3) nano

  11. Ion transport in Titan's upper atmosphere M. Galand,1

    E-print Network

    Yelle, Roger V.

    Click Here for Full Article Ion transport in Titan's upper atmosphere J. Cui,1 M. Galand,1 R. V measurements made during nine close encounters of the Cassini spacecraft with Titan, we investigate escape from Titan with a total ion loss rate of (1.7 ± 0.4) × 1025 s-1 . Significant diurnal variation

  12. Titan atmosphere database P. Rannou a,*, S. Lebonnois b

    E-print Network

    Hourdin, Chez Frédéric

    Titan atmosphere database P. Rannou a,*, S. Lebonnois b , F. Hourdin b , D. Luz c a Service d 2005 Abstract We have developed in the last decade a two-dimensional version of the Titan global circulation model LMDZ. This model accounts for multiple coupling occuring on Titan between dynamics, haze

  13. Intelligent Systems for the Autonomous Exploration of Titan and Enceladus

    E-print Network

    Arizona, University of

    Intelligent Systems for the Autonomous Exploration of Titan and Enceladus Roberto Furfaro and further exploring regions on Titan and/or Enceladus that have the highest potential to yield evidence and understanding of Titan and Enceladus environments is evaluated to define a path for the design of a fuzzy

  14. The lakes of Titan E. R. Stofan1,2

    E-print Network

    LETTERS The lakes of Titan E. R. Stofan1,2 , C. Elachi3 , J. I. Lunine4 , R. D. Lorenz5 , B. Stiles Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar

  15. Titan: a long way from grad school at Michigan

    E-print Network

    Jurdy, Donna M.

    NASA/JPL Titan: a long way from grad school at Michigan All paths lead to where Titan: Even so far away it's the temperature! #12;A. D. Fortes/UCL/STFC Cassini at Titan under a distant sun. #12;Needed for habitability: Solid surface Atmosphere Liquid on surface: need

  16. Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by a Titanate

    E-print Network

    Zhang, Xumu

    Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by a Titanate Complex with a Chiral of this alkylation reaction can also be catalyzed by chiral titanate complexes2-4 (e.g., TAD- DOLs2 and chiral sulfonamides3 ). We have recently studied a titanate complex with tetradentate helical ligand 1 ((1R,2R)-(+)-1

  17. Tuesday, March 24, 2009 POSTER SESSION I: TANTALIZING TITAN

    E-print Network

    Rathbun, Julie A.

    Tuesday, March 24, 2009 POSTER SESSION I: TANTALIZING TITAN 6:30 p.m. Town Center Exhibit Area Hayne P. McCord T. B. Barnes J. W. Titan's Near Infrared Atmospheric Transmission and Surface target method, we calculate Titan's atmospheric transmission and surface albedo in the 0.8 - 5.0 micron

  18. Insolation in Titan's troposphere Juan M. Lora a,

    E-print Network

    Russell, Joellen

    Insolation in Titan's troposphere Juan M. Lora a, , Paul J. Goodman b , Joellen L. Russell b Accepted 18 August 2011 Available online 31 August 2011 Keywords: Titan Radiative transfer a b s t r a c t Seasonality in Titan's troposphere is driven by latitudinally varying insolation. We show that the latitu

  19. The search for Titan lightning radio emissions G. Fischer1

    E-print Network

    Gurnett, Donald A.

    The search for Titan lightning radio emissions G. Fischer1 and D. A. Gurnett2 Received 1 March 2011­detection of radio emissions indicative of Titan lightning by the Cassini RPWS (Radio and Plasma Wave Science) instrument. A previous study by Fischer et al. (2007) investigated the first 35 Titan flybys, and here we

  20. The Dynamics Behind Titan's Methane Clouds Jonathan L. Mitchell1

    E-print Network

    Frierson, Dargan

    The Dynamics Behind Titan's Methane Clouds Jonathan L. Mitchell1 , Raymond T. Pierrehumbert2 circulation model of Titan with a simplified suite of atmospheric physics forced by seasonally varying insolation. The recent discovery of midlatitude tropospheric clouds on Titan has caused much excitement about