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1

Enhanced piezoelectric properties of lead zirconate titanate (PZT) sol-gel derived ceramics using single crystal PZT cubes  

NASA Astrophysics Data System (ADS)

Piezoceramic materials have attracted much attention for sensing, actuation, structural health monitoring and energy harvesting applications in the past two decades due to their excellent coupling between energy in the mechanical and electrical domains. Among all piezoceramic materials, lead zirconate titanate (PZT) has been the most broadly studied and implemented, in industrial applications due to its high piezoelectric coupling coefficients. Piezoceramic materials are most often employed as thin films or monolithic wafers. While there are numerous methods for the synthesis of PZT films, the sol-gel processing technique is the most widely used due to its low densification temperature, the ease at which the film can be applied without costly physical deposition equipment and the capability to fabricate both thin and thick films. However, the piezoelectric properties of PZT sol-gel derived films are substantially lower than those of bulk materials, which limit the application of sol-gel films. In comparison, single crystal PZT materials have higher piezoelectric coupling coefficients than polycrystalline materials due to their uniform dipole alignment. This paper will introduce a novel technique to enhance the piezoelectric properties of PZT sol-gel derived ceramics through the use of single crystal PbZr0.52Ti0.48O3 microcubes as an inclusion in the PZT sol-gel. The PZT single crystal cubes are synthesized through a hydrothermal based method and their geometry and crystal structure is characterized through scanning electron microscopy (SEM) and X-ray diffraction (XRD). A mixture of PZT cubes and sol-gel will then be sintered to crystallize the sol-gel and obtain full density of the ceramic. XRD and SEM analysis of the cross section of the final ceramics will be performed and compared to show the crystal structure and microstructure of the samples. The P-E properties of the samples will be tested using a Sawyer-Tower circuit. Finally, a laser interferometer will be used to directly measure the piezoelectric strain-coupling coefficient of the PZT sol-gel ceramics with and without PZT cube inclusions. The results will show that with the integration of PZ0.52T0.48 crystal inclusions the d33 coupling coefficient will increase more than 200% compared to that of pure PbZr0.52Ti0.48O3 sol-gel.

Lin, Yirong; Andrews, Clark; Sodano, Henry A.

2010-04-01

2

Mechanical and dielectric characterization of lead zirconate titanate(PZT)/polyurethane(PU) thin film composite for energy harvesting  

NASA Astrophysics Data System (ADS)

The Lead Zirconate titanate (PZT) ceramic is known by its piezoelectric feature, but also by its stiffness, the use of a composite based on a polyurethane (PU) matrix charged by a piezoelectric material, enable to generate a large deformation of the material, therefore harvesting more energy. This new material will provide a competitive alternative and low cost manufacturing technology of autonomous systems (smart clothes, car seat, boat sail, flag ...). A thin film of the PZT/PU composite was prepared using up to 80 vol. % of ceramic. Due to the dielectric nature of the PZT, inclusions of this one in a PU matrix raises the permittivity of the composite, on other hand this latter seems to decline at high frequencies.

Aboubakr, S.; Rguiti, M.; Hajjaji, A.; Eddiai, A.; Courtois, C.; d'Astorg, S.

2014-04-01

3

Crystal structure and microstructure of lead zirconate titanate (PZT) thin films with various Zr\\/Ti ratios grown by hybrid processing  

Microsoft Academic Search

Lead zirconate titanate (Pb(ZrxTi1?x)O3: PZT) thin films were fabricated on Pt\\/Ti\\/SiO2\\/Si(100) substrates by a hybrid process comprising the sol–gel method and pulsed-laser deposition, using various targets of Pb(ZrxTi1?x)O3 with Zr\\/Ti ratios of 70\\/30, 58\\/42, 52\\/48, 45\\/55 and 30\\/70. The effect of Zr\\/Ti ratio on the crystal structure and microstructure of the PZT films was investigated. The results of X-ray diffraction

Zhan Jie Wang; Yuki Aoki; Li Jun Yan; Hiroyuki Kokawa; Ryutaro Maeda

2004-01-01

4

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

E-print Network

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

Ramesh, R.

5

Direct printing of lead zirconate titanate thin films  

E-print Network

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 ...

Bathurst, Stephen, 1980-

2008-01-01

6

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

E-print Network

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 the influence of grain size on the piezoelectric properties in PZT ceramics. In general, grain-size studies were

Cao, Wenwu

7

Response of piezoelectric lead zirconate titanate to high-energy xenon ion beam pulse  

NASA Astrophysics Data System (ADS)

To develop a new radiation detector, the characteristics of piezoelectric lead zirconate titanate (PZT) are currently being studied using a 400 MeV/n xenon (Xe) beam. In this study, the response of the PZT element to the pulsed beam was investigated by changing the beam intensity. It was found that the time distribution of the Xe ions in the pulse duration must be taken into account to understand the formation of the output signal that appeared on the PZT element.

Takechi, Seiji; Miura, Yoshinori; Mitsuhashi, Tomoaki; Miyachi, Takashi; Kobayashi, Masanori; Okudaira, Osamu; Shibata, Hiromi; Fujii, Masayuki; Okada, Nagaya; Murakami, Takeshi; Uchihori, Yukio

2014-11-01

8

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

NASA Astrophysics Data System (ADS)

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.

Ehmke, Matthias Claudius

9

Examination of barrier layers for lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

The selection of a suitable electrode and barrier layer are important in the integration of Lead Zirconate Titanate (PZT) into memory circuits. Five materials were evaluated using physical analysis techniques as possible barrier layers. Glancing-angle x-ray diffraction was used as the initial assessment to determine the structure of the PZT. With either silicon or MoSi2 as a base layer, it was not possible to obtain a perovskite PZT structure under the conditions investigated. Although the desired crystal structure could be obtained with TiN as a base material, the oxygen-rich sputtering conditions for PZT had transformed this layer to an oxide making it unsuitable as electrode. PZT grown on an indium tin oxide (ITO) coated glass substrate also had a perovskite structure and good electrical properties. Scanning electron microscopy showed good adhesion between the layers, but transmission electron microscopy and secondary ion mass spectroscopy revealed Pb-rich areas residing in the glass beneath the ITO. PZT on platinum appeared to be the only promising barrier layer studied as there was no indication of Pb diffusion into the underlying layers and the desired crystal structure was obtained.

Madsen, Lynnette D.; Weaver, Louise

1992-01-01

10

Evolution of a stable polarization state in lead zirconate titanate ceramics by repeated partial switching  

NASA Astrophysics Data System (ADS)

The development of the ferroelectric polarization of lead-zirconate-titanate (PZT) bulk ceramics under varying electric fields is examined. Repeated partial switching and backswitching results in a decrease of the switchable polarization, but has no effect on the effective strain. This is attributed to a stabilization of the domain structure, which leads to a decrease of the electric losses. The results are discussed with respect to the effective strain of PZT ceramics for piezoelectric actuators.

Granzow, T.; Balke, N.; Lupascu, D. C.; Rödel, J.

2005-11-01

11

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

SciTech Connect

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.

Tang, Haixiong, E-mail: htang15@ufl.edu, E-mail: hsodano@ufl.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Malakooti, Mohammad H. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Sodano, Henry A., E-mail: htang15@ufl.edu, E-mail: hsodano@ufl.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2013-11-25

12

Dielectric and pyroelectric properties of lead zirconate titanate/polyurethane composites  

SciTech Connect

0-3 composite ranging between 0 and 3, of ferroelectric ceramic lead zirconate titanate (PZT) and thermoplastic elastomer polyurethane (PU) were fabricated. The pyroelectric and dielectric properties of the hot-pressed thin film samples of various PZT volume fractions were measured. The experimental dielectric permittivities and losses agreed reasonably well with the Bruggeman model. The room temperature pyroelectric coefficients of the composites were found to increase linearly with PZT volume fraction and substantially larger than expected. For example, for a composite with 30% PZT, its pyroelectric coefficient is about 90 {mu}C/m{sup 2}K at room temperature, which is more than tenfold of a PZT/PVDF composite of the same ceramic volume fraction. We propose a model in which the electrical conductivity of the composite system is taken into consideration to explain the linear relationship and the extraordinarily large pyroelectric coefficients obtained.

Lam, K.S.; Wong, Y.W.; Tai, L.S.; Poon, Y.M.; Shin, F.G. [Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)

2004-10-01

13

Water-induced degradation in lead zirconate titanate piezoelectric ceramics  

NASA Astrophysics Data System (ADS)

Water-induced degradation in lead zirconate titanate (PZT) piezoelectric ceramics was studied by a comparison experiment. In one treatment, PZT rings were immersed in a 0.01 M NaOH solution for long periods of time; in the other treatment, PZT rings were placed in a 0.01 M NaOH solution and hydrogen was evolved onto their silver electrodes by the electrolysis of water. No degradation occurred to samples immersed in the NaOH solution; but for the samples that were also treated by electrolysis of water, serious degradation occurred as their mechanical quality factor decreased dramatically and their dielectric loss increased considerably. I-V measurement showed that the resistance decreased greatly in the degraded samples, which could be explained by the formation of charge carriers due to the reduction reaction of atomic hydrogen from the electrolysis of water. It was proposed that the reduction reaction of atomic hydrogen at ambient temperature is an important origin for the degradation of piezoelectric ceramic devices.

Chen, W. P.; Chan, H. L. W.; Yiu, F. C. H.; Ng, K. M. W.; Liu, P. C. K.

2002-05-01

14

Helmholtz Resonator for Lead Zirconate Titanate Acoustic Energy Harvester  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

15

Electrostriction of lead zirconate titanate/polyurethane composites  

SciTech Connect

Electrostriction of a ferroelectric inclusion/nonferroelectric matrix composite system was studied. The samples were prepared by blending the lead zirconate titanate (PZT) particles with the thermoplastic polyurethane through extrusion and subsequently by hot pressing. Quasistatic cyclic electric fields were applied across the samples while strains and currents were monitored simultaneously. It was found that the electrostriction of the composites depended on the applied electric field in a hysteretic manner. In particular at the high-field regime, the samples exhibited a reversal in the electrostrictive strain. This switching effect occurred at a critical field which was inversely proportional to the PZT content. An associated increase in the displacement current with the critical field was also observed. It indicates that the switching in strain of the composites was mainly due to the flipping of the PZT dipoles in the nonferroelectric polymer matrix. A model was developed for describing the electrostriction behavior of this composite system and the calculated results are comparable to the experimental curves. The success of this theoretical model encourages its application further to the ferroelectric-ferroelectric composite systems.

Lam, K.S.; Zhou, Y.; Wong, Y.W.; Shin, F.G. [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)

2005-05-15

16

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

SciTech Connect

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.

Amelichev, V. V., E-mail: V.Amelichev@tcen.ru [Moscow State Institute of Electronic Engineering, NPK Technological Center (Russian Federation); Saikin, D. A.; Roshchin, V. M.; Silibin, M. V. [Moscow State Institute of Electronic Engineering (Technical University) (Russian Federation)

2010-12-15

17

New type of piezo-damping epoxy-matrix composites with multi-walled carbon nanotubes and lead zirconate titanate  

Microsoft Academic Search

A new type of rigid piezo-damping epoxy-matrix composites containing multi-walled carbon nanotubes (CNT) and piezoelectric lead zirconate titanate (PZT) was prepared, and the electrical and the damping properties were investigated. Dynamic mechanical thermal analysis reveals that the loss factors of the composites were improved by incorporation of PZT and CNT under the concentration above a critical electrical percolation. Based on

Sheng Tian; Fangjin Cui; Xiaodong Wang

2008-01-01

18

Optimization of PZT processing using thermal ink-jet printing  

E-print Network

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 ...

Jeon, Jessie Sungyun

2008-01-01

19

Ink jet printing of PZT thin films for MEMS  

E-print Network

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 ...

Bathurst, Stephen, 1980-

2012-01-01

20

Magnetoelectric CoFe2O4-lead zirconate titanate thick films prepared by a polyvinylpyrrolidone-assisted sol-gel method  

Microsoft Academic Search

Magnetoelectric CoFe2O4-PZT (lead zirconate titanate) films as thick as 1 mum have been prepared by spin coating using a PZT sol-gel solution containing polyvinylpyrrolidone and CoFe2O4 powder. X-ray diffraction result reveals that there exists no chemical reaction or phase diffusion between the CoFe2O4 and PZT phases. The scanning electron microscopy observation confirms that the composite thick film is crack-free and

Jian-Guo Wan; Hao Zhang; Xiuwei Wang; Dengyu Pan; Jun-Ming Liu; Guanghou Wang

2006-01-01

21

Effects of sintering temperature on microstructure and high field strain of niobium-strontium doped morphotropic lead zirconate titanate  

Microsoft Academic Search

Electric field induced strain is one of the most important performance parameters for multilayer ferroelectric actuators. In these devices, donor doped morphotropic lead zirconate titanate (PZT) ceramics are the materials currently used. Strain and, more general, electromechanical properties of these piezoceramics are grain size dependent. Any attempts to decrease the sintering temperature will suffer from the drawback, that changing Ts

Hans Kungl; Michael J. Hoffmann

2010-01-01

22

Structural contribution to the ferroelectric fatigue in lead zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

Many ferroelectric devices are based on doped lead zirconate titanate (PZT) ceramics with compositions near the morphotropic phase boundary (MPB), at which the relevant material's properties approach their maximum. Based on a synchrotron x-ray diffraction study of MPB PZT, bulk fatigue is unambiguously found to arise from a less effective field induced tetragonal-to-monoclinic transformation, at which the degradation of the polarization flipping is detected by a less intense and more diffuse anomaly in the atomic displacement parameter of lead. The time dependence of the ferroelectric response on a structural level down to 250 ?s confirms this interpretation in the time scale of the piezolectric strain response.

Hinterstein, M.; Rouquette, J.; Haines, J.; Papet, Ph.; Glaum, J.; Knapp, M.; Eckert, J.; Hoffman, M.

2014-09-01

23

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

SciTech Connect

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.

Kesim, M. T.; Zhang, J.; Alpay, S. P. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Trolier-McKinstry, S. [Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, Pennsylvania 16802 (United States); Mantese, J. V. [United Technologies Research Center, East Hartford, Connecticut 06118 (United States); Whatmore, R. W. [Tyndall National Institute, Lee Maltings, Dyke Parade, Cork City, County Cork (Ireland)

2013-11-28

24

Properties of ultra-thin lead zirconate titanate thin films prepared by ozone jet reactive evaporation  

SciTech Connect

Lead zirconate titanate (PZT) thin films were prepared by reactive coevaporation with high-concentration ozone. PZT thin films that demonstrate the highest charge storage density (280 fC/{mu}m{sup 2} at 1.5 V for 75-nm-thick film) yet reported have been fabricated. No fatigue was observed after 10{sup 11} polarization switching cycles even though a Pt electrode is used. A low leakage current of {lt}10{sup {minus}7} A/cm{sup 2} at 1.5 V was attained. These PZT films are promising candidates of an alternative capacitor dielectric for dynamic random access memory (DRAM) and ferroelectric nonvolatile memories. {copyright} {ital 1997 American Institute of Physics.}

Torii, K.; Kawakami, H.; Miki, H.; Kushida, K.; Fujisaki, Y. [Central Research Laboratory, Hitachi, Limited, 1-280 Higashi koigakubo, Kokubunji, 185, Tokyo (Japan)] [Central Research Laboratory, Hitachi, Limited, 1-280 Higashi koigakubo, Kokubunji, 185, Tokyo (Japan)

1997-03-01

25

Phase separation in lead zirconate titanate and bismuth titanate during electrical shorting and fatigue  

NASA Astrophysics Data System (ADS)

Micro-Raman and electron microprobe techniques are used to show that lead zirconate titanate and samarium-doped bismuth titanate undergo local phase transformations and separation during electrical shorting and in the dendritic precursors to microshorts caused by bipolar fatigue. These precursors for shorts, consisting of dark filaments, were studied just before they completely shorted the sample. The aim of the study was to compare electrical breakdown and breakdown precursors in ABO3 perovskite oxides and related Aurivillius phase layer structures with Bi (A site) substitution and with B-site substitution (e.g., Ti for Zr in PZT). The observation of phase separation and decomposition is related to congruent and incongruent meltings in these materials. Dendritelike shorts and short precursors of a few microns in diameter, produced by extreme bipolar voltage cycling fatigue, are mapped spectroscopically in 1 ?m2 areas and exhibit almost pure regions of ?-PbO, ?-PbO, and rutile TiO2. The ?-? PbO phase boundary runs from 500 °C at 1 atm to room temperature at 0.4 GPa, easily accessible temperatures and pressures in the dynamical process. Similarly, under large dc voltages the Sm-doped bismuth titanate transforms from a layered-perovskite structure to a pyrochlore structure during filamentary electrical breakdown, with the loss of Bi. The interfacial phase separation has been attributed to the combination of defect aggregation and thermal decomposition effects.

Lou, Xiaojie; Hu, Xiaobing; Zhang, Ming; Morrison, F. D.; Redfern, S. A. T.; Scott, J. F.

2006-02-01

26

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

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

27

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

28

Leakage and reliability characteristics of lead zirconate titanate thin-film capacitors  

SciTech Connect

Resistance degradation in lead zirconate titanate (Pb-(Zr,Ti)O{sub 3}, PZT) thin-film capacitors has been studied as a function of applied voltage, temperature, and film composition. The mean time-to-failure (lifetime, or t{sub f}) of the capacitors shows a power-law dependence on voltage of the form t{sub f} inversely proportional to V{sup {minus}n} (n {approx} 4--5). The capacitor lifetime also exhibits a temperature dependence of the form t{sub f} inversely proportional to exp[E{sub a}/(kT)], with an activation energy of 0.6--1.0 eV. The stead-state leakage current in these samples seems to be bulk controlled. The voltage V, temperature T, and polarity dependence of the leakage current collectively suggest a leakage-current mechanism that is most similar to a Frenkel-Poole process. The t{sub f} value and the leakage current of niobium-doped PZT films are superior to those of undoped PZT films. This result can be explained on the basis of the point-defect chemistry of the PZT system. Finally, the results indicate that the niobium-doped PZT films meet essential t{sub f} requirements for decoupling-capacitor applications.

Al-Shareef, H.N.; Dimos, D. [Sandia National Labs., Albuquerque, NM (United States)

1997-12-01

29

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

30

Hydrogen diffusion in Lead Zirconate Titanate and Barium Titanate  

SciTech Connect

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.

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

2012-08-28

31

Hydrogen diffusion in lead zirconate titanate and barium titanate  

NASA Astrophysics Data System (ADS)

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.

Alvine, K. J.; Vijayakumar, M.; Bowden, M. E.; Schemer-Kohrn, A. L.; Pitman, S. G.

2012-08-01

32

Infrared spectra and second-harmonic generation in barium strontium titanate and lead zirconate-titanate thin films: ``Polaron'' artifacts  

NASA Astrophysics Data System (ADS)

We report infrared absorption spectroscopy and second-harmonic generation data for barium strontium titanate (BST) and lead zirconate-titanate (PZT) ceramic films in the 3000-5500 cm-1 region. Second-harmonic generation experiments give temperature dependences in accord with oxygen vacancy cluster theory [S. A. Prosandeev, Sov. Phys. JETP 83, 747 (1996); S. A. Prosandeev, V. S. Vikhnin, and S. Kapphan, Integr. Ferroelectr. 32, 1047 (2001); J. Phys. Condens. Matter 14, 4407 (2002)]. A percolation model of vacancy ordering is discussed. The present work shows that earlier data interpreted as polaron spectra in these films were actually artifacts due to interference in the optical apparatus used [B. Guettler, U. Bismayer, P. Groves, and E. Salje, Semicond. Sci. Technol. 10, 245 (1950]; more recent "polaron" spectra in WO3 films may also be artifacts [L. Berggren, A. Azens, and G. A. Niklassson, J. Appl. Phys. 90, 1860 (2001)]. Numerical estimates of the polaron mass m**=16me in SrTiO3 and BST help prove that dielectric data in strontium titanate interpreted as bipolarons [A. Levstik et al., Appl. Phys. Lett. 81, 4046 (2002)] are also artifacts.

Scott, J. F.; Jiang, A. Q.; Redfern, S. A. T.; Zhang, Ming; Dawber, M.

2003-09-01

33

Fabrication, Electrical, and Material Characterization of Lead Zirconate Titanate Thin Film Capacitors for Semiconductor Memory Applications.  

NASA Astrophysics Data System (ADS)

In this work, ferroelectric lead zirconate titanate (PZT) thin film capacitors with charge storage densities that exceeds the requirements of 256 Mb DRAM storage dielectric applications have been successfully developed. The excellent electrical properties of PZT thin film capacitors fabricated with Pt electrodes indicate that PZT might be an attractive candidate for storage applications in ULSI semiconductor memories. The electrical properties of the Pt/PZT/Pt capacitors have been evaluated for a range of ferroelectric film compositions and thicknesses. Excellent fatigue endurance under both unipolar and bipolar AC electrical stress under actual operating conditions for 256 Mb applications (3V) were observed. The device lifetime under low frequency and high field AC stress was found to be 2-3 orders of magnitude better than under low field DC stress. The leakage current density of 10^{-7} A/cm ^2 at 3V for our devices is amongst the lowest reported so far in literature. The impact of various device fabrication sequences on the electrical and material properties have been studied and the best approach adopted. The entire process flow for PZT thin film deposition, post deposition thermal processing, and device fabrication sequence was critically analyzed to identify the important issues and optimize device properties. The importance of Pb content in the pyrochlore -to-perovskite phase transformation kinetics has been demonstrated, and the annealing ambient effects and the evolution of the perovskite phase with post-deposition annealing have been studied. The variation in the phase transformation kinetics, and electrical and reliability properties of Pb (Zr _{rm x} Ti_ {rm 1-x}) O_3 (PZT) thin films with a variation in Zr/Ti ratio were evaluated. Rapid phase transformation was observed for the composition close to the Morphotropic Phase Boundary (MPB) even for low thermal budget input during the post-deposition annealing step. The usable temperature processing window was found to decrease with a scaling down of the PZT film thickness. Furthermore, a degradation in the leakage current level at 3 V and degradation voltage is observed as the PZT film thickness was reduced. Significant resistivity recovery effects under open-circuit wait-time conditions are observed in devices that are stressed into the resistance degradation regime.

Chikarmane, Vinay B.

34

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

SciTech Connect

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by a softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform so 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.

Frantti, Johannes [Aalto University, Finland; Fujioka, Y [Aalto University, Finland; Puretzky, Alexander A [ORNL; Xie, Y [Simon Fraser University, Canada; Glazer, A [Clarendon Laboratory, Department of Physics, University of Oxford

2013-01-01

35

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

SciTech Connect

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.

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

2012-01-01

36

Piezoelectric and dielectric performance of poled lead zirconate titanate subjected to electric cyclic fatigue  

NASA Astrophysics Data System (ADS)

Poled lead zirconate titanate (PZT) material as a single-layer plate was tested using a piezodilatometer under electric cyclic loading in both unipolar and bipolar modes. Its responses were evaluated using unipolar and bipolar measurements on the same setup. The mechanical strain and charge density loops exhibited various variations when the material was cycled for more than 108 cycles. The various quantities including loop amplitude, hysteresis, switchable polarization, and coercive field were characterized accordingly under the corresponding measurement conditions. At the same time, the 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 conditions also. Finally, the piezoelectric and dielectric coefficients were analyzed and their implications for the application of interest have been discussed.

Wang, Hong; Matsunaga, Tadashi; Lin, Hua-Tay; Mottern, Alexander M.

2012-02-01

37

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

SciTech Connect

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.

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

2013-01-01

38

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

NASA Astrophysics Data System (ADS)

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 × 105 to 7 × 105 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 108 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. Furthermore, involved fatigue and failure mechanisms were investigated using scanning acoustic microscope and scanning electron microscope. The extensive cracks and porous regions were revealed across the PZT layers on the cross sections of a failed actuator. 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 test and monitor the behavior of PZT stacks.

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

2013-07-01

39

Study of the characteristics of a piezoelectric lead zirconate titanate radiation detector using a pulsed xenon source  

SciTech Connect

The detector characteristics of piezoelectric lead zirconate titanate (PZT) were studied by directly irradiating a multilayered PZT detector with 400 MeV/n xenon ions. An extracted beam was processed with a rotating slit. Thus, passed through {approx}10{sup 3} xenon ions were available for 50 to 250 {mu}s. The effect of polarization on the output signal was discussed, and the optimal electrode configuration was determined. The output signal appeared as an isolated pulse whose amplitude was qualitatively understood by the Bethe-Bloch formula. However, the calculated and the observed values differed depending on the rotation speed of the slit. A process that can explain the differences is presented here. The output signal appearing beyond the range of 400 MeV/n xenon ion beam was discussed. The sensitivity was compared with that obtained with hypervelocity collision of dust.

Miyachi, Takashi [Research Institute of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Fujii, Masayuki; Hasebe, Nobuyuki; Okudaira, Osamu [Research Institute of Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Takechi, Seiji; Kurozumi, Atsuma; Morinaga, Shinya; Uno, Takefumi [Graduate School of Engineering, Osaka-City University, Osaka 558-8585 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto-University, Kyoto-606-8501 (Japan); Kobayashi, Masanori [Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Okada, Nagaya [Honda Electronics Co. Ltd., Toyohashi, Aichi 441-3193 (Japan)

2010-05-15

40

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

PubMed

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

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

2011-06-01

41

Direct effect of illumination on ferroelectric properties of lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

Photosensitive ferroelectric materials exhibit various photoferroelectric phenomena due to the strong influence of nonequilibrium charge carriers on polarization and phase transition. These phenomena are essential for a number of applications including photodriven actuators and sensitive photodetectors. In this work, the effect of UV illumination on dielectric and piezoelectric properties is investigated in lead zirconate titanate (PZT) thin films, which are currently the most promising material for microactuator applications. The effective piezoelectric coefficient (d33) and dielectric permittivity (?) of PZT films are simultaneously measured under a weak ac electric field during illumination with a band gap light (?=280-400 nm). It is shown that both d33 and ? decrease under UV illumination. The reduction of permittivity, however, is much smaller than that of d33 and demonstrates a much slower time relaxation. The d33 decrease is attributed to the reduction of average remanent polarization under the UV light. Thus a direct effect of the photoactive light on ferroelectric polarization is observed under essentially nondestructive (weak-field) conditions. The origin of the observed effect is discussed along with the possible implications for thin-film devices.

Kholkin, A. L.; Iakovlev, S. O.; Baptista, J. L.

2001-09-01

42

Lead Zirconate Titanate Thick Films Fabricated from Sols with and without Its Powder  

NASA Astrophysics Data System (ADS)

Sol modified with diethanolamine was used for the preparation of thick lead zirconate titanate (PZT) films. The deposited films crystallized in the perovskite structure by heating above 600°C. Thick film with 3 ?m single-coating thickness was obtained using a dip-coating of sol containing PZT powder. The resultant thick films were porous and the pores could not be filled with a cover coating of powder-free sol. The dielectric properties of the thick and porous films prepared using powder-containing sols were poor, although they exhibited ferroelectric polarization-electric field (P-E) hysteresis. Using the powder-free sol, a film with thickness >1 ?m was realized on the Sn-doped In2O3(ITO)/glass substrate by a single deposition. The resultant film was dense and about 5.6 ?m thick after five depositions. The film showed a saturated ferroelectric P-E hysteresis curve and the dielectric constant, loss tangent, and remanent polarization were 840, 0.03, and 34 ?C/cm2, respectively.

Ohya, Yutaka; Itoda, Satoru; Ban, Takayuki; Takahashi, Yasutaka

2002-01-01

43

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

E-print Network

University of Seoul Seoul, 130-743 Korea 4 Mechanical and Aerospace Engineering North Carolina State of Mathematics North Carolina State University Raleigh, NC 27695 3 Mechanical and Information Engineering

44

Crack tip 90 domain switching in tetragonal lanthanum-modified lead zirconate titanate under an  

E-print Network

Crack tip 90° domain switching in tetragonal lanthanum-modified lead zirconate titanate under) Lanthanum-modified lead zirconate titanate ferroelectric ceramics (Pb0.96La0.04)(Zr0.40Ti0.60)0.99O3 were revealed the residual domain switching in a trans- parent relaxor-type ferroelectric 9.4/65/35 lanthanum

Zhu, Ting

45

Electric-fieldtemperature phase diagram of the relaxor ferroelectric lanthanum-modified lead zirconate titanate  

E-print Network

Electric-field­temperature phase diagram of the relaxor ferroelectric lanthanum-modified lead in the electric-field­temperature phase diagram of 9/65/35 lanthanum-modified lead zirconate titanate ceramics ferroelectrics. S0163-1829 99 00233-7 I. INTRODUCTION Lanthanum-modified lead zirconate titanate ceramics Pb1 x

Bobnar, Vid

46

Ageing and fatigue of lead titanate and lead zirconate titanate thin ferroelectric films  

NASA Astrophysics Data System (ADS)

The phenomena of ageing and fatigue have been experimentally investigated in lead titanate and lead zirconate titanate thin ferroelectric films for samples on different substrates and with different materials of the measuring electrodes. A certain broadening of the dielectric permittivity peak is observed for the films on the silicon substrate after a year keeping without external actions. The lead titanate films on corundum substrates did not demonstrate visible changes in structural and dielectric parameters in the course of this time. In the course of repeated cycling the reduction of switching polarization in the lead titanate and lead zirconate titanate films on silicon substrates takes place at considerably greater number of cycles as compared to the same films on corundum substrates under the identical conditions. The above changes of dielectric and switching characteristics can be relevant to the changes in the domain structure of the materials under investigation in the process of their ageing and repeated switching. The reason for the acceleration of the ageing processes in the films on corundum substrates could be either an increase in the absolute magnitude of the switching field or an increase of the internal bias field, that facilitate the migration of oxygen vacancies in the films with the perovskite structure to the electrode-ferroelectric surface with the consequent fixation of domain walls.

Sidorkin, Andrey; Nesterenko, Lolita; Sidorkin, Alexander; Ryabtsev, Stanislav; Bulavina, Galina

2010-03-01

47

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

NASA Astrophysics Data System (ADS)

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.

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

1999-09-01

48

Lead zirconate titanate-based thick films for high-frequency focused ultrasound transducers prepared by electrophoretic deposition.  

PubMed

An electrophoretic deposition (EPD) process with high deposition rate was used to fabricate a curved piezoelectric thick film devoted to high-frequency transducers for medical imaging. Niobium-doped lead zirconate titanate (PZTNb) powder was stabilized in ethanol to prepare a suspension with high zeta potential and low conductivity. A gold layer, pad-printed and fired on a curved porous PZT substrate, was used as the working electrode for the deposition of the PZTNb thick film. This substrate was chosen because it has the required properties (acoustic impedance and attenuation) to be used directly as a backing for the high-frequency transducer, leading to a simplified process for transducer assembly with this integrated structure. PZT-Nb thick films were also deposited by EPD on flat gold-coated alumina substrates as a reference. The thickness of the films was between 20 and 35 ?m, and their electromechanical performance was comparable to standard PZT bulk ceramics with a thickness coupling factor of 48%. For the curved thick film, the thickness coupling factor was slightly lower. The corresponding integrated structure was used to fabricate a transducer with a center frequency of 40 MHz and an f-number of 2.8. It was integrated into a realtime ultrasound scanner and used to image human forearm skin; the resulting images showed, for the first time, the efficacy of the EPD process for these imaging applications. PMID:24569258

Abellard, André-Pierre; Kuscer, Danjela; Grégoire, Jean-Marc; Lethiecq, Marc; Malic, Barbara; Levassort, Franck

2014-03-01

49

Neutron irradiation effects on domain wall mobility and reversibility in lead zirconate titanate thin films  

SciTech Connect

The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16 {+-} 0.03) Multiplication-Sign 10{sup 15} cm{sup -2}. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was observed accompanied by the formation of a secondary hysteron peak following exposure to high fluence levels. The changes are attributed to the radiation-induced formation of defect dipoles and other charged defects, which serve as effective domain wall pinning sites. Differences in damage accumulation rates with initial film quality were observed between the film sets suggesting a dominance of pre-irradiation microstructure on changes in macroscopic switching behavior.

Graham, Joseph T. [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States); Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Brennecka, Geoff L.; Ihlefeld, Jon F. [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ferreira, Paulo [Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78751 (United States); Small, Leo [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Duquette, David [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Apblett, Christopher [Advanced Power Sources R and D Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Landsberger, Sheldon [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States)

2013-03-28

50

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

NASA Astrophysics Data System (ADS)

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.

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

2006-04-01

51

In situ neutron diffraction studies of a commercial, soft lead zirconate titanate ceramic: Response to electric fields and mechanical stress  

SciTech Connect

Structural changes in commercial lead zirconate titanate (PZT) ceramics (EC-65) under the application of electric fields and mechanical stress were measured using neutron diffraction instruments at the Australian Nuclear Science and Technology Organisation (ANSTO) and the Oak Ridge National Laboratory (ORNL). The structural changes during electric-field application were measured on the WOMBAT beamline at ANSTO and include non-180{sup o} domain switching, lattice strains and field-induced phase transformations. Using time-resolved data acquisition capabilities, lattice strains were measured under cyclic electric fields at times as short as 30 {mu}s. Structural changes including the (002) and (200) lattice strains and non-180{sup o} domain switching were measured during uniaxial mechanical compression on the NRSF2 instrument at ORNL. Contraction of the crystallographic polarization axis, (002), and reorientation of non-180{sup o} domains occur at lowest stresses, followed by (200) elastic strains at higher stresses.

Pramanick, Abhijit [University of Florida; Prewitt, Anderson [University of Florida; Cottrell, Michelle [University of Florida; Lee, Wayne [ITT Corporation Acoustic Sensors; Studer, Andrew J. [Bragg Institute, ANSTO; An, Ke [ORNL; Hubbard, Camden R [ORNL; Jones, Jacob [University of Florida

2010-01-01

52

Enhanced piezoelectric properties of lead zirconate titanate sol-gel derived ceramics using single crystal PbZr0.52Ti0.48O3 cubes  

NASA Astrophysics Data System (ADS)

Piezoceramic materials have attracted much attention for sensing, actuation, structural health monitoring, and energy harvesting applications in the past two decades due to their excellent coupling between energy in the mechanical and electrical domains. Among all piezoceramic materials, lead zirconate titanate (PZT) has been the most broadly studied and implemented, in industrial applications due to its high piezoelectric coupling coefficients. Piezoceramic materials are most often employed as thin films or monolithic wafers. While there are numerous methods for the synthesis of PZT films, the sol-gel processing technique is the most widely used due to its low densification temperature, the ease at which the film can be applied without costly physical deposition equipment and the capability to fabricate both thin and thick films. However, the piezoelectric properties of PZT sol-gel derived films are substantially lower than those of bulk materials, which limit the application of sol-gel films. In comparison, single crystal PZT materials have higher piezoelectric coupling coefficients than polycrystalline materials due to their uniform dipole alignment. This paper will introduce a novel technique to enhance the piezoelectric properties of PZT sol-gel derived ceramics through the use of single crystal PbZr0.52Ti0.48O3 microcubes as an inclusion in the PZT sol-gel. The PZT single crystal cubes are synthesized through a hydrothermal based method and their geometry and crystal structure is characterized through scanning electron microscopy (SEM) and x-ray diffraction (XRD). A mixture of PZT cubes and sol-gel will then be sintered to crystallize the sol-gel and obtain full density of the ceramic. XRD and SEM analysis of the cross section of the final ceramics will be performed and compared to show the crystal structure and microstructure of the samples. The P-E properties of the samples will be tested using a Sawyer-Tower circuit. Finally, a laser interferometer will be used to directly measure the piezoelectric strain-coupling coefficient of the PZT sol-gel ceramics with and without PZT cube inclusions. The results will show that with the integration of PZT crystal inclusions the d33 coupling coefficient will increase more than 200% compared to that of pure PbZr0.52Ti0.48O3 sol-gel.

Lin, Yirong; Andrews, Clark; Sodano, Henry A.

2010-09-01

53

Sensors and Actuators A 116 (2004) 369377 Demonstration and characterization of PZT thin-film sensors and  

E-print Network

-film sensors and actuators for meso- and micro-structures Yi-Chu Hsua, Chia-Che Wub, Cheng-Chun Leeb, G.Z. CaocSensors and Actuators A 116 (2004) 369­377 Demonstration and characterization of PZT thin, such as endoscopes and hearing aids, call for PZT (lead zirconate titanate oxide) thin-film sensors and actuators

Cao, Guozhong

54

Pulsed laser deposition and ferroelectric characterization of nanostructured perovskite lead zirconate titanate (52/48) thin films.  

PubMed

Perovskite lead zirconate titanate nanostructured (PZT) thin films with Zr/Ti ratio of 52/48 were deposited on Pt/TiO2/SiO2/Si(100) substrate using pulsed laser deposition method. A metal/ ferroelectric/metal (MFM) structure was used for ferroelectric property measurements, formed by depositing gold electrode on top of the film. A Nd:YAG UV laser having a wavelength of 355 nm and an energy fluence of -2.7 J/cm2 was used to deposit the film. The film was deposited on platinum (Pt) coated silicon substrate at the substrate temperature of 600 degrees C and the base vacuum of 10(-6) mbar. The scanning electron microscopy (SEM) images revealed well-crystallized films with a fine microstructure and an average grain size of - 50 nm. The ferroelectric properties of the film were studied and the results were discussed. The voltage dependent Polarization versus Electric field hysteresis measurements of PZT (52/48) pellet showed a well-defined hysteresis loop with a fairly high remnant polarization (P(r)) and low coercive field (E(c)). PMID:23755624

Prabu, M; Banu, I B Shameem; Vijayaraghavan, G V; Gobalakrishnan, S; Chavali, Murthy

2013-03-01

55

Seeding effect on the fatigue behaviour of PZT thin films  

Microsoft Academic Search

Lead zirconate titanate films (PZT) of the morphotropic phase boundary composition were prepared using a diol-based sol-gel route modified by introducing 1–5 mol% PZT nano-seeds (with the same composition as the films). Thin films derived from unseeded and seeded precursors were fabricated on platinised silicon substrates (Pt\\/Ti\\/SiO2\\/Si). The effects of the concentration of seeds on the hysteresis behaviour and fatigue

Aiying Wu; P. M. Vilarinho; A. L. Kholkin; I. M. Salvado Miranda; J. L. Baptista

2001-01-01

56

Raman study of lead zirconate titanate under uniaxial stress  

SciTech Connect

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.

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

2000-04-01

57

Determination of metal impurities in advanced lead zirconate titanate ceramics by axial view mode inductively coupled plasma optical emission spectrometry.  

PubMed

An inductively coupled plasma optical emission spectrometry quantification method for the determination of Al, Ca, Cr Cu, Fe, Mn, Mg, Ni, Zn, Ba, K, In and Co in lead zirconate-titanate (PZT) ceramics, modified with strontium and chromium, was developed. Total digestion of ceramics was achieved with a HNO(3), H(2)O(2) and HF (ac) mixture by using a microwave furnace. The sensitivity of the net signal intensity respect to radiofrequency power (P) and nebulizer argon flow (F(N)) variations was strongly dependent of the total excitation energy of line (TEE). For lines with TEE near metastable atoms and ions of argon, an increment of the sensitivities to P and F(N) variation was observed. At robust plasma conditions the matrix effect was reduced for all matrices and analytes considered. The precision of analysis ranged from 3 to 13%, whereas the analytes recoveries in the spiked samples varied, mostly, from 90 to 110%. The detection limits of studied elements were from 0.004 to 10 mg kg(-1). PMID:22608413

Villanueva Tagle, M E; Larrea Marín, M T; Martin Gavilán, O; Durruthy Rodríguez, M D; Calderón Piñar, F; Pomares Alfonso, M S

2012-05-30

58

Relaxor freezing and electric-field induced ferroelectric transition in a lanthanum lead zirconate titanate ceramics  

Microsoft Academic Search

Transition lines between various phases in the electric-field temperature phase diagram of 9\\/65\\/35 lanthanum lead zirconate titanate ceramics were determined by measurements of the temperature and electric-field dependent dielectric constant. Above the critical field (EC) the dc bias electric field induces a transition from the relaxor to the ferroelectric phase, while below EC the system exhibits a freezing transition between

V. Bobnar; Z. Kutnjak; R. Pirc; A. Levstik

1999-01-01

59

Temperature Dependence of Piezoelectric, Dielectric, and Elastic Properties of Lead Lanthanum Zirconate Titanate Ceramics  

Microsoft Academic Search

The piezoelectric resonance and the ferroelectric hysteresis loopin 8\\/65\\/35 lead lanthanum zirconate titanate (PLZT) ceramics were measuredsimultaneously at temperatures ranging from 20 to 140°C. The complexelastic compliance and the complex piezoelectric and dielectric constantswere extracted from the piezoelectric resonance data, while thetemperature-dependent remanent polarization and coercive field were obtainedfrom the ferroelectric hysteresis loops. From the temperature behavior of theabove quantities,

Vid Bobnar; Zdravko Levstik; andAdrijan Levstik

1998-01-01

60

Dielectric properties of partially disordered lanthanum-modified lead zirconate titanate relaxor ferroelectrics  

Microsoft Academic Search

Linear and third-order nonlinear dielectric susceptibilities and the dielectric polarization were measured in 6.5\\/65\\/35 lanthanum lead zirconate titanate (PLZT) hot-pressed ceramics. On cooling linear dielectric data show a transition from an ergodic to a nonergodic relaxor phase, while, on heating, a ferroelectric to ergodic relaxor phase transition appears. The third-order dielectric response is reminiscent of an ergodic to nonergodic relaxor

Boris Vodopivec; Cene Filipic; Adrijan Levstik; Janez Holc; Zdravko Kutnjak; Horst Beige

2004-01-01

61

Electric-field-temperature phase diagram of the relaxor ferroelectric lanthanum-modified lead zirconate titanate  

Microsoft Academic Search

Transition lines between various phases in the electric-field-temperature phase diagram of 9\\/65\\/35 lanthanum-modified lead zirconate titanate ceramics were determined by measurements of the temperature and electric-field-dependent dielectric constant. Above a critical field (EC) the dc bias electric field induces a transition from the relaxor (R) to the long-range ferroelectric (FE) phase. In the temperature direction of the approach to the

Vid Bobnar; Zdravko Kutnjak; Rasa. Pirc; Adrijan Levstik

1999-01-01

62

Slow dynamics and ergodicity breaking in a lanthanum-modified lead zirconate titanate relaxor system  

Microsoft Academic Search

The freezing of the dynamic process in a 9\\/65\\/35 lanthanum lead zirconate-titanate (PLZT) ceramics has been investigated by measurements of the frequency-dependent complex dielectric constant and the quasistatic field-cooled (FC) and zero-field-cooled (ZFC) dielectric susceptibilities. It was found that the aging process is responsible for the difference in temperature variations of the FC static dielectric constant and the static dielectric

Zdravko Kutnjak; Cene Filipic; Rasa. Pirc; Adrijan Levstik; Robert Farhi; Mimoun El Marssi

1999-01-01

63

Fabrication of transparent lead lanthanum zirconate titanate ceramics from fine powders by two-stage sintering  

Microsoft Academic Search

This paper reports that transparent lead lanthanum zirconate titanate (PLZT) ceramics were fabricated from fine powders using an inexpensive two-stage sintering technique. The powders were prepared by hydrolysis from low-cost inorganic precursors. In the two-stage sintering method, uniaxially pressed green pelets were densified to nearly theoretical values in an oxygen gas atmosphere during the first-stage sintering, at 1000[degrees]C for 1

Yoshio Yoshikawa; Kaoru Tsuzuki

1992-01-01

64

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

Microsoft Academic Search

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;

Kelley Markowski; Seung-Eek Park; Shoko Yoshikawa; L. Eric Cross

1996-01-01

65

MEMS power generator with transverse mode thin film PZT  

Microsoft Academic Search

A thin film lead zirconate titanate, Pb(Zr,Ti)O3 (PZT), MEMS power generating device is developed. It is designed to resonate at specific frequencies from an external vibrational energy source, thereby creating electrical energy via the piezoelectric effect. Our cantilever device is designed to have a flat structure with a proof mass added to the end. The Pt\\/Ti top electrode is patterned

Y. B. Jeon; R. Sood; J.-h. Jeong; S.-G. Kim

2005-01-01

66

Compact piezoelectric micromotor with a single bulk lead zirconate titanate stator  

NASA Astrophysics Data System (ADS)

The advance of micro/nanotechnology promotes the development of micromotors in recent years. In this article, a compact piezoelectric ultrasonic micromotor with a single bulk lead zirconate titanate stator is proposed. A traveling wave is generated by superposition of bending modes with 90° phase difference excited by d15 inverse piezoelectric effects. The operating principle simplifies the system structure significantly, and provides a miniaturization solution. A research prototype with the size of 0.75× 0.75×1.55 mm is developed. It can produce start-up torque of 0.27?Nmand maximum speed of 2760 r/min at 14RMS.

Yan, Liang; Lan, Hua; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

2013-04-01

67

Lead lanthanum zirconate stannate titanate based antiferroelectric to ferroelectric phase switching multilayer ceramic actuators  

Microsoft Academic Search

Lead lanthanum zirconate stannate titanate (PLZST) based antiferroelectric to ferroelectric phase switching multilayer ceramic actuators were prepared by the tape casting method. The ceramic powders used were synthesized by a two-step wet chemical method using colloidal processing with a composition of Pb0.97La0.02(Zr0.65Sn0.25Ti0.10)O3. The actuators sintered at 1100°C with Pd\\/Ag internal electrode and consisted of 20 active layer of 40?m thick.

Chen Ming; Yao Xi; Zhang Liangying

2001-01-01

68

Field forced antiferroelectric-to-ferroelectric switching in modified lead zirconate titanate stannate ceramics  

SciTech Connect

Electric-field-forced antiferroelectric- to-ferroelectric phase transitions in several compositions of modified lead zirconate titanate stannate antiferroelectric ceramics are studied for ultra-high-field-induced strain actuator applications. Two types of fatigue effects are observed in these ceramic compositions. In one, the fatigue effects only proceed to a limited extent and the properties may be restored by annealing above the Curie temperature, while in the other, the fatigue effects proceed to a large extent and the properties cannot be restored completely by heat treatment.

Pan, W.; Zhang, Q.; Bhalla, A.; Cross, L.E. (Materials Research Lab., Pennsylvania State Univ., University Park, PA (US))

1989-04-01

69

Sensitivity analysis of piezoelectric paint sensors made up of PZT ceramic powder and water-based acrylic polymer  

Microsoft Academic Search

A strain sensor based on piezoelectric paint film has been designed to be used in structural vibration monitoring applications. The piezoelectric paint film can be considered as a piezoelectric composite constituted by two phases: lead zirconate titanate (PZT) ceramic powder (active phase) homogeneously distributed in a water-based acrylic polymer (passive phase). Two electrodes placed to both sides of the film

Ismael Payo; J. M. Hale

2011-01-01

70

Low Temperature Sintering of PZT  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

71

Barium zirconate-titanate/barium calcium-titanate ceramics via sol-gel process: novel high-energy-density capacitors  

NASA Astrophysics Data System (ADS)

Lead-free barium zirconate-titanate/barium calcium-titanate, [(BaZr0.2Ti0.80)O3]1-x-[(Ba0.70Ca0.30)TiO3]x (x = 0.10, 0.15, 0.20) (BZT-BCT) ceramics with high dielectric constant, low dielectric loss and moderate electric breakdown field were prepared by the sol-gel synthesis technique. X-ray diffraction patterns revealed tetragonal crystal structure and this was further confirmed by Raman spectra. Well-behaved ferroelectric hysteresis loops and moderate polarizations (spontaneous polarization, Ps ~ 3-6 µC cm-2) were obtained in these BZT-BCT ceramics. Frequency-dependent dielectric spectra confirmed that ferroelectric diffuse phase transition (DPT) exists near room temperature. Scanning electron microscope images revealed monolithic grain growth in samples sintered at 1280 °C. 1000/? versus (T) plots revealed ferroelectric DPT behaviour with estimated ? values of ~1.52, 1.51 and 1.88, respectively, for the studied BZT-BCT compositions. All three compositions showed packing-limited breakdown fields of ~47-73 kV cm-1 with an energy density of 0.05-0.6 J cm-3 for thick ceramics (>1 mm). Therefore these compositions might be useful in Y5V-type capacitor applications.

Sreenivas Puli, Venkata; Kumar, Ashok; Chrisey, Douglas B.; Tomozawa, M.; Scott, J. F.; Katiyar, Ram S.

2011-10-01

72

Water-Induced Degradation in Lead Zinc Niobate Lead Zirconate Titanate Soft Piezoelectric Ceramics  

NASA Astrophysics Data System (ADS)

Water-induced degradation of lead zinc niobate-lead zirconate titanate (Pb(Zn1/3Nb2/3)O3-Pb(ZrTi)O3) soft piezoelectric ceramics is studied using electrochemical hydrogen charging, in which the silver electrodes of the piezoelectric ceramics constitute a cathode in 0.01-M NaOH solution to evolve hydrogen by electrolysis of water. It is found that with the increasing hydrogen charging time, the resonance impedance increases, the difference between the resonance frequency and the anti-resonance frequency decreases, the spontaneous polarization, the remanent polarization and the piezoelectric coefficient d33 decrease. The degradation behaviour of the soft piezoelectric ceramics can be explained to hydrogen incorporating into the lattice and forming hydroxy (OH-) bonds in the perovskite structure, which prevents the Ti ions from switching and increases the coercive field Ec. The degradation characteristics of the soft piezoelectric ceramics are quite different from that of lead zirconate titanate hard piezoelectric ceramics.

Jiang, Xiang-Ping; Chen, Wan-Ping; Peng, Zhi; Zeng, Min; Chan-Wang, Li-Hua; Yin, Qing-Rui

2005-05-01

73

PVDF-PZT nanocomposite film based self-charging power cell  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

74

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

PubMed

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

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

2014-03-14

75

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

E-print Network

on the devel- opment of thin film technologies for ferroelectric materials.1-5 Ferroelectric materials, actuating, and processing information. MEMS may include such fabricated devices as accelerometers, infrared piezoelectric and pyro- electric properties of inorganic ferroelectric materials into MEMS devices. Currently

Aksay, Ilhan A.

76

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

SciTech Connect

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 (9594x10{sup -15} m{sup 2}/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.

Yang Ankun; Wang Changan; Guo Rui; Huang Yong [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

2011-04-11

77

Evolution of bias field and offset piezoelectric coefficient in bulk lead zirconate titanate with fatigue  

SciTech Connect

Hysteresis loops of the piezoelectric coefficient, d{sub 33}=f(E{sub 3}), are measured on virgin and fatigued lead zirconate titanate ceramics. Four parameters are directly extracted from the measurements: internal bias field E{sub b}, offset piezoelectric coefficient d{sub offset}, coercive field E{sub c}, and remnant piezoelectric coefficient d{sub r}. The reduction in d{sub r} displays the decreasing switchable polarization with fatigue cycling. E{sub b} and d{sub offset} are found to be linearly related. After thermal annealing, both offsets disappear, while the increase in E{sub c} and the reduction in d{sub r} withstand annealing. The microscopic entities responsible for the offsets are less stable than those for reduced switching.

Zhang Yong; Baturin, Ivan S.; Aulbach, Emil; Lupascu, Doru C.; Kholkin, Andrei L.; Shur, Vladimir Ya.; Roedel, Juergen [Institute of Materials Science, Darmstadt University of Technology, 64287 Darmstadt (Germany); Institute of Physics and Applied Mathematics, Ural State University, Ekaterinburg 620083 (Russian Federation); Institute of Materials Science, Darmstadt University of Technology, 64287 Darmstadt (Germany); Department of Ceramics and Glass Engineering and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Institute of Physics and Applied Mathematics, Ural State University, Ekaterinburg 620083 (Russian Federation); Institute of Materials Science, Darmstadt University of Technology, 64287 Darmstadt (Germany)

2005-01-03

78

Electric field induced phase transition of antiferroelectric lead lanthanum zirconate titanate stannate ceramics  

SciTech Connect

The electric field induced phase transition behavior of lead lanthanum zirconate titanate stannate (PLZTS) ceramics was investigated. PLZTS undergoes a tetragonal antiferroelectric (AFE{sub Tet}) to rhombohedral ferroelectric (FE{sub Rh}) phase transition with the application of an electric field. The volume increase associated with this antiferroelectric (AFE){endash}ferroelectric (FE) phase transition plays an important role with respect to actuator applications. This volume increase involves an increase in both transverse and longitudinal strains. The E field at which the transverse strain increases is accompanied by an abrupt jump in polarization. The longitudinal strain, however, lags behind this polarization jump exhibiting a slight decrease at the onset of phase switching. This decoupling was related to the preferentially oriented AFE domain configuration, with its tetragonal c-axis perpendicular to the applied electric field. It is suggested that phase switching involves multiple steps involving both structural transformation and domain reorientation. {copyright} {ital 1997 American Institute of Physics.}

Park, S.; Pan, M.; Markowski, K.; Yoshikawa, S.; Cross, L.E. [Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

1997-08-01

79

Dielectric properties of lead lanthanum zirconate stanate titanate antiferroelectric thin films prepared by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Lead lanthanum zirconate stanate titanate (PLZST) thin films of approximately 200 nm in thickness were deposited on Pt-buffered silicon substrates using pulsed laser deposition method. The samples were prepared under different substrate temperatures but with the same oxygen partial pressure of 0.2 mbar and laser fluence of approximately 4 J/cm2. We found that the Pb loss during the deposition process plays an important role in the formation of perovskite phase. Postdeposition annealing under different oxygen pressure, ranging from 0.2 mbar to atmospheric oxygen pressure but for the same annealing duration (15 min), was carried out in order to clarify the effects of the annealing ambient, from the viewpoint of crystallographic structure as well as electrical and dielectric properties. The physical origin is discussed.

Yao, Yingbang; Zhai, Jiwei; Chen, Haydn

2004-06-01

80

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

NASA Astrophysics Data System (ADS)

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.

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

81

A cross-junction channel valveless-micropump with PZT actuation  

Microsoft Academic Search

A gas-jet micro pump with novel cross-junction channel has been designed and fabricated using a Si micromachining process.\\u000a The valveless micro pump is composed of a piezoelectric lead zirconate titanate (PZT) diaphragm actuator and fluidic network.\\u000a The design of the valveless pump focuses on a cross-junction formed by the neck of the pump chamber and one outlet and two\\u000a opposite

Van Thanh Dau; Thien Xuan Dinh; Tanaka Katsuhiko; Sugiyama Susumu

2009-01-01

82

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

PubMed

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

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

2014-05-14

83

Preparation and structural characterization of rare-earth doped lead lanthanum zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

A new preparation route towards rare-earth (RE) doped polycrystalline lead lanthanum zirconate titanate (PLZT) ceramics (RE = Y 3+, Nd 3+, Yb 3+), based on the use of doped lanthanum oxide or zirconia, is reported. Structural characterization by X-ray powder diffraction reveals that secondary phase formation can be substantially diminished in comparison to conventional preparation methods. The distribution of the rare-earth dopants was investigated as a function of concentration by static 207Pb spin echo NMR spectra, using Fourier Transformation of Carr-Purcell-Meiboom-Gill spin echo trains. For the Nd- and Yb-doped materials, the interaction of the 207Pb nuclei with the unpaired electron spin density results in significant broadening and shifting of the NMR signal, whereas these effects are absent in the diamagnetic Y 3+ doped materials. Based on different concentration dependences of the NMR lineshape parameters, we conclude that the structural role of the Nd 3+ dopants differs significantly from that of Yb 3+. While the Nd 3+ ions appear to be statistically distributed in the PLZT lattice, incorporation of Yb 3+ into PLZT appears to be limited by the appearance of doped cubic zirconia as a secondary phase.

de Queiroz, Thiago Branquinho; Mohr, Daniel; Eckert, Hellmut; de Camargo, Andrea S. S.

2009-08-01

84

Crystal structure and electrical properties of bismuth sodium titanate zirconate ceramics  

PubMed Central

Lead-free bismuth sodium titanate zirconate (Bi0.5Na0.5Ti1-xZrxO3 where x = 0.20, 0.35, 0.40, 0.45, 0.60, and 0.80 mole fraction) [BNTZ] ceramics were successfully prepared using the conventional mixed-oxide method. The samples were sintered for 2 h at temperatures lower than 1,000°C. The density of the BNTZ samples was at least 95% of the theoretical values. The scanning electron microscopy micrographs showed that small grains were embedded between large grains, causing a relatively wide grain size distribution. The density and grain size increased with increasing Zr concentration. A peak shift in X-ray diffraction patterns as well as the disappearance of several hkl reflections indicated some significant crystal-structure changes in these materials. Preliminary crystal-structure analysis indicated the existence of phase transition from a rhombohedral to an orthorhombic structure. The dielectric and ferroelectric properties were also found to correlate well with the observed phase transition. PMID:22221595

2012-01-01

85

A Piezoelectric Plethysmograph Sensor Based on a Pt Wire Implanted Lead Lanthanum Zirconate Titanate Bulk Ceramic  

PubMed Central

This work reports on the development of a Lead Lanthanum Zirconate Titanate (PLZT) bulk ferroelectric poled ceramic structure as a Piezoelectric Plethysmograph (PZPG) sensor. The ceramic was implanted during its fabrication with a platinum (Pt) wire which works as an internal electrode. The ceramic was then submitted to an experimental setup in order to validate and determine the Pt-wire mechanical effects. This PZPG sensor was also mounted on a finger splint in order to measure the blood flow that results from the pulsations of blood occurring with each heartbeat. Fingertip pulses were recorded jointly with an ECG signal from a 25 year old male to compare the time shift; the PZPG sensor guarantees the electrical isolation of the patient. The proposed PZPG has several advantages: it can be adjusted for fingertip measurements, but it can easily be extended by means of spare bands, therefore making possible PZPG measurements from different body locations, e.g., forehead, forearm, knee, neck, etc. PMID:22163596

González-Morán, Carlos O.; Flores-Cuautle, J.J. Agustín; Suaste-Gómez, Ernesto

2010-01-01

86

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

SciTech Connect

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.

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

2009-06-01

87

Directed colloidal assembly and characterization of PZT-polymer composites  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT)-based layers and 3-D structures were directly assembled using two colloidal routes: (1) tape casting and (2) a layer-by-layer robotic deposition technique, known as robocasting. First, concentrated (?solids > 0.45) suspensions of PZT-5H and a latex emulsion were tape cast with the aid of viscosifier and surfactant additions. Drying stress evolved to a maximum at ? PZT ˜ 0.49, followed by a reduction and a secondary stress rise attributed to latex coalescence. Dielectric and piezoelectric properties of sintered PZT multilayer laminates exhibited good agreement with those for isostatically pressed and sintered samples. Concentrated, weakly gelled suspensions of PZT 95/5 and poly(ethylene) (PE) latices, a fugitive species, were developed as inks for the robotic deposition of monolithic and tri-layered composite structures. Monoliths, with densities of 93.6% and 96.1%, and composites with a 96.1% dense layer between 93.6% regions were fabricated. The structures displayed equivalent electrical properties to cold isostatically pressed parts. The composites withstood repeated saturation polarization switching as well as a 500 MPa hydrostatic pressure-induced poled ferroelectric (FE) to antiferroelectric (AFE) phase transformation. Concentrated (?PZT = 0.47) PZT-5H gels were developed as inks for the robotic deposition of 3-D, mesoscale periodic structures with self-supporting features such as lattices of rod-like elements and v-shaped test structures. The gels exhibited pH dependent viscoelastic properties and Hershel-Bulkley flow behavior. The deflection of as-deposited spanning elements was measured using laser profilometry. Flow modeling and shape evolution data indicated a core-shell architecture as the ink exited the deposition nozzle, which simultaneously provided strength to form spanning elements and good bonding between layers. The core grew rapidly (˜1s) due to the quick recovery of gel structure in these inks. 3-X type PZT-polymer composites consisting of PZT lattices in a polymer matrix (3-3), a lattice/polymer matrix with PZT faceplates (3-2), or a lattice/polymer matrix with faceplates and encircled by a solid PZT ring (3-1) were formed and their piezoelectric properties were characterized. The PZT:polymer ratio was controlled by the lattice spacing in these thin composites (˜1 mm). Lattice rod intersections formed high permittivity, low compliance PZT pillars that concentrated stress and electric flux, leading to improved hydrostatic figures of merit.

Smay, James Earl

88

Growth and measurements of ferroelectric lead zirconate titanate on diamond by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Pb(Zr0.53Ti0.47)O3 (PZT) on diamond is a potentially robust structure for surface acoustic wave (SAW) device applications. We have studied the growth and physical characteristics of PZT on diamond and other substrates by pulsed laser deposition. Under a broad range of processing conditions we explored, PZT deposited directly on diamond is almost exclusively pyrochlore-type, which is nonferroelectric. Growth of ferroelectric perovskite PZT is promoted via the use of a PbTiO3 buffer layer within a narrow window of processing parameters [i.e., P(O2)=100-200 mTorr, T=550-650 °C, 1-2 J/cm2]. Similar results were also obtained for deposition of PZT on Si, Pt-coated Si, and Pt-coated diamond substrates. The dielectric constants of the perovskite PZT films are 500-650 at 1 V and 100 kHz. The piezoelectric coefficients of these films are in the range of 50×10-12-350×10-12 m/V. The SAW velocity of perovskite PZT films is similar to that of highly oriented sputter deposited ZnO films. The acoustic attenuation in perovskite PZT films is approximately three times higher than that in ZnO, however.

Du, H.; Johnson, D. W.; Zhu, W.; Graebner, J. E.; Kammlott, G. W.; Jin, S.; Rogers, J.; Willett, R.; Fleming, R. M.

1999-08-01

89

Dielectric and Ferroelectric Properties of Lead Lanthanum Zirconate Titanate Thin Films for Capacitive Energy Storage  

NASA Astrophysics Data System (ADS)

As the increasing requirement of alternative energy with less pollution influence and higher energy efficient, new energy source and related storage methods are hot topic nowadays. Capacitors that supply high instant power are one of the keys in this application for both economic and functional design aspects. To lower the cost and increases the volumetric efficiency and reliability, relaxor thin films are considered as one of the candidates of the next generation capacitors. The research mainly focuses on dielectric and ferroelectric properties of lead lanthanum zirconate titanate or Pb1-xLax(ZryTi1-y)O3 (PLZT, x/y/1-y) relaxor thin films deposited on silicon (Si) and nickel (Ni) substrates in a range of thickness with different bottom electrodes, e.g. Platinum (Pt) and LaNiO3 (LNO). The final fabricated PLZT film capacitors will show strong potential for the energy storage application. The method adopted is the acetic acid assisted sol-gel deposition for the PLZT thin films. The wet chemical process is cost-effective and easily to scale up for plant/industrial products. We investigated the different bottom electrode/substrate influence in structure, microstructure, phases/defects, and heat-treatment conditions to achieve the optimized PLZT thin films. Issues of basic physical size effects in the PLZT thin films were also investigated, including thickness effects in the dielectric and ferroelectric properties of the films in a wide range of temperatures, the phase transition of the thin-film relaxors, lanthanum content effect, electrode-dielectric junction, misfit strain effect, etc. Based on the results and analysis, optimum PLZT film capacitors can be determined of proper substrate/electrode/dielectric that achieves the desired dielectric properties required for different applications, especially a more cost-effective method to develop volumetrically efficient capacitors with high charge density, energy density, dielectric breakdown strength, energy storage efficiency, and low dielectric loss, leakage current density.

Tong, Sheng

90

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

NASA Astrophysics Data System (ADS)

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(Zr0.45Ti0.55)O3 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.

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

2014-08-01

91

A combination of PZT and EMAT transducers for interface inspection.  

PubMed

A PZT (Lead Zirconate-Titanate) transducer requires a couplant to send and receive mechanical waves. This requirement is a major shortcoming of the PZT technique for use in field applications. In the laboratory environment careful considerations and surface treatments are required to use PZT because the couplant can affect the consistency of experimental results. One alternative to overcome this shortcoming is the use of EMAT (ElectroMagnetic Acoustic Transducer). However, EMAT gives relatively low transmitted ultrasonic energy, with low signal to noise ratio, and the induced energy is critically dependent on the probe proximity to the test object. These are not desirable properties for NDT (nondestructive testing) of civil infrastructures. That is why, in this paper, a combination of PZT and EMAT is introduced for investigating reinforced concrete structures. Interface defects between steel bars and concrete are investigated by this technique. It is shown that the PZT-EMAT combination is very effective for steel bar-concrete interface inspection and the guided waves are useful for nondestructive testing of civil infrastructures. PMID:12051433

Na, Won-Bae; Kundu, Tribikram

2002-05-01

92

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)

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.

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

93

From lab to industrial: PZT nanoparticles synthesis and process control for application in additive manufacturing  

NASA Astrophysics Data System (ADS)

Lead Zirconate Titanate (PZT) nanoparticles hold many promising current and future applications, such as PZT ink for 3-D printing or seeds for PZT thick films. One common method is hydrothermal growth, in which temperature, duration time, or mineralizer concentrations are optimized to produce PZT nanoparticles with desired morphology, controlled size and size distribution. A modified hydrothermal process is used to fabricate PZT nanoparticles. The novelty is to employ a high ramping rate (e.g., 20 deg C/min) to generate abrupt supersaturation so as to promote burst nucleation of PZT nanoparticles as well as a fast cooling rate (e.g., 5 deg C/min) with a controlled termination of crystal growth. As a result, PZT nanoparticles with a size distribution ranging from 200 nm to 800 nm are obtained with cubic morphology and good crystallinity. The identification of nanoparticles is confirmed through use of X-ray diffractometer (XRD). XRD patterns are used to compare sample variations in their microstructures such as lattice parameter. A cubic morphology and particle size are also examined via SEM images. The hydrothermal process is further modified with excess lead (from 20% wt. to 80% wt.) to significantly reduce amorphous phase and agglomeration of the PZT nanoparticles. With a modified process, the particle size still remains within the 200 nm to 800 nm. Also, the crystal structures (microstructure) of the samples show little variations. Finally, a semi-continuous hydrothermal manufacturing process was developed to substantially reduce the fabrication time and maintained the same high quality as the nanoparticles prepared in an earlier stage. In this semi-continuous process, a furnace is maintained at the process temperature (200 deg C), whereas autoclaves containing PZT sol are placed in and out of the furnace to control the ramp-up and cooling rates. This setup eliminates an extremely time-consuming step of cooling down the furnace, thus saving tremendous amount of process time making fabrication of a large amount of PZT nanoparticles possible.

Huang, Hsien-Lin

94

1.6 V nanogenerator for mechanical energy harvesting using PZT nanofibers.  

PubMed

Energy harvesting technologies that are engineered to miniature sizes, while still increasing the power delivered to wireless electronics, (1, 2) portable devices, stretchable electronics, (3) and implantable biosensors, (4, 5) are strongly desired. Piezoelectric nanowire- and nanofiber-based generators have potential uses for powering such devices through a conversion of mechanical energy into electrical energy. (6) However, the piezoelectric voltage constant of the semiconductor piezoelectric nanowires in the recently reported piezoelectric nanogenerators (7-12) is lower than that of lead zirconate titanate (PZT) nanomaterials. Here we report a piezoelectric nanogenerator based on PZT nanofibers. The PZT nanofibers, with a diameter and length of approximately 60 nm and 500 microm, were aligned on interdigitated electrodes of platinum fine wires and packaged using a soft polymer on a silicon substrate. The measured output voltage and power under periodic stress application to the soft polymer was 1.63 V and 0.03 microW, respectively. PMID:20499906

Chen, Xi; Xu, Shiyou; Yao, Nan; Shi, Yong

2010-06-01

95

Titan  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

96

Electrochemistry of ferroelectric thin film lead zirconate titanate in sulfuric acid  

NASA Astrophysics Data System (ADS)

Remote sensing applications in harsh environments require sensor materials appropriately matched to the environment. PbZr0.52Ti0.48O 3 (PZT) is a candidate for remote sensing applications, where it could be used as both a sensor and power source. In this light, the evolution of the PZT-H2SO4 interface is explored at low pHs. A robotic microdroplet cell is developed to differentiate the electrochemical response of the cracks and pores inherent to the PZT film from that of continuous PZT. Accelerated chemical attack is observed at the pores, while the continuous PZT displays electrochemical hysteresis; the ferroelectric-solution interface can be switched between two different charge states at a given potential. As time progresses, electrochemical impedance spectroscopy reveals a change in the structure of the PZT-H2SO4 interface. Development of equivalent circuits to model the competing processes of pore growth, interfacial layer formation, and uniform chemical attack are guided by the evolution of film structure and chemistry as observed ex-situ with scanning electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction. The Point Defect Model for the passive state is used to explain the dissolution processes observed in the complex oxide. Application of this model to PbZrxTi1- xO3 for x = 0.25, 0.52, and 0.95 points to the role of titanium in the creation of an ionically insulating layer that impedes further chemical attack.

Small, Leo J.

97

Cavitand-coated PZT resonant piezo-layer sensors: properties, structure, and comparison with QCM sensors at different temperatures under exposure to organic vapors  

Microsoft Academic Search

AT-cut thickness-shear mode quartz crystal microbalance (QCM) sensors and resonant piezo-layer (RPL) sensors made by lead zirconate titanate (PZT) thick films were sensitized with cavitand coatings (Qx-Cav and Me-Cav) and exposed to organic vapors of environmental interest. Responses at different temperatures are compared. Effects due to the temperature dependence of the partition coefficient and the porosity of RPL sensors are

M. Ferrari; V. Ferrari; D. Marioli; A. Taroni; M. Suman; E. Dalcanale

2004-01-01

98

Residual stress effects on piezoelectric response of sol-gel derived lead zirconate titanate thin films  

E-print Network

or compressive of the film stress are highly dependent on both the processing technique and the properties-field behavior. The diminished performance associated with high residual stresses is attributed to reductions.47 O3 PZT thin films. Residual stresses in electroceramic thin films can be very high but are often

Sottos, Nancy R.

99

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

SciTech Connect

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.

Narayanan, M.; Tong, S.; Ma, B.; Liu, S.; Balachandran, U. (Energy Systems)

2012-01-01

100

Deposition and characterization of thin ferroelectric lead lanthanum zirconate titanate (PLZT) films on sapphire for spatial light modulators applications.  

PubMed

Ferroelectric lead lanthanum zirconate titanate (PLZT) films are deposited on R-plane sapphire using RF triode magnetron sputtering. Perovskite PLZT films with the desired composition (9/65/35) are obtained using compensated deposition techniques around 500 degrees C and postdeposition annealing at 650 degrees C. The deposited films exhibit good optical and electrooptical properties. The room temperature dielectric constant of the films was 1800 at 10 kHz. The refractive index of the films was in the range of 2.2-2.5. The films showed a quadratic electrooptic effect with R=0.6 x10(-16) m(2)/V(2). The development of PLZT on silicon-on-sapphire smart spatial light modulators using these films is also explored. PMID:18267622

Krishnakumar, S; Ozguz, V H; Fan, C; Cozzolino, C; Esener, S C; Lee, S H

1991-01-01

101

Microfabrication of PZT force sensors for minimally invasive surgical tools  

NASA Astrophysics Data System (ADS)

Minimally invasive surgery (MIS) is the most exciting and rapidly developing area where force sensing is actually of central importance. Micromachined piezoelectric sensors can be integrated onto MIS tools for improved diagnosis and treatment monitoring. A micro-machined freestanding lead zirconate titanate (PZT) force sensor is fabricated using five masks process incorporating deep reactive ion, ion beam and wet-chemical etching techniques. The PZT sensor is designed as a parallel plate capacitor structure in which the sol-gel prepared 1-µm thick PZT film is sandwiched between top (Au/Cr) and bottom (Pt/Ti) metal electrodes mounted on a thin Si membrane. This paper also describes a new wet chemical approach for patterning PbZr0.52Ti0.48O3 films. The etch recipe provided excellent etch control, minimized undercut, preserved the photoresist mask, and effectively removed the residues on the etched surfaces. A high etch rate (200 nm/min), high selectivity with respect to photoresist, and limited under-cutting (1.5:1, lateral : thickness) were obtained. The fabricated force sensor exhibited good ferroelectric properties. The current fabrication procedure and electrical analysis can be considered as a breakthrough for fabricating freestanding PZT force sensor in any desired shape and dimensions, as well as a good example of ferroelectric microdevices.

Ezhilvalavan, S.; Zhang, Zaoli; Loh, Jeremy; Ying, Jackie Y.

2006-04-01

102

Effect of External Vibration on PZT Impedance Signature  

PubMed Central

Piezoelectric ceramic Lead Zirconate Titanate (PZT) transducers, working on the principle of electromechanical impedance (EMI), are increasingly applied for structural health monitoring (SHM) in aerospace, civil and mechanical engineering. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the monitored structure is only excited by the PZT transducers for the interrogating of EMI signature, while the vibration of the structure caused by the external excitations other than the PZT actuation is not considered. However, many structures work under vibrations in practice. To monitor such structures, issues related to the effects of vibration on the EMI signature need to be addressed because these effects may lead to misinterpretation of the structural health. This paper develops an EMI model for beam structures, which takes into account the effect of beam vibration caused by the external excitations. An experimental study is carried out to verify the theoretical model. A lab size specimen with different external excitations is tested and the effect of vibration on EMI signature is discussed.

Yang, Yaowen; Miao, Aiwei

2008-01-01

103

Ultrasonic Imaging for Poling Uniformity Measurements in PZT Ceramic Elements  

SciTech Connect

This report summarizes the results of a project sponsored by Honeywell Corporation (formerly AlliedSignal Inc.) Federal Manufacturing and Technologies/Kansas City (FM and T/KC) and conducted jointly with the University of Missouri, Rolla, titled ''Ultrasonic Imaging for Poling Uniformity Measurements in PZT Ceramic Elements.'' In this three-month research project, a series of experiments was performed on soft and hard lead-zirconate-titanate (PZT) structures to determine the effectiveness of ultrasonic measurements as a nondestructive method of evaluating poling quality and uniformity. The study revealed that acoustic velocity correlates well with the degree of poling of PZT structures, as predicted by elastic theory. Additionally, time-of-flight (TOF) imaging was shown to be an ideal tool for viewing the spatial distribution of poled material and of material affected by the electric field beyond the edge of electroded regions. Finally, the effectiveness of ultrasonic methods for flaw detection and evaluation of PZT/stainless steel bonds was also demonstrated.

Jamieson, E.E.

2000-03-14

104

Preparation and characterization of PZT solid solutions via sol gel process  

NASA Astrophysics Data System (ADS)

The present research describes a modified sol-gel process that has been developed for the preparation of lead zirconate titanate (PZT) (0.52/0.48) powders. In this route, diethanolamine (DEA) was used as a complexing agent to keep the metal ions in homogeneous solutions without undergoing precipitation. Drying treatment led to development of transparent gel network. Phase-pure perovskite structure was formed at 500 °C. The crystallization behavior of the sol-gel-derived powders was studied by X-ray diffraction (XRD) and simultaneous thermal analysis. Differences between the sequence of phase formation encountered in the traditional (oxide-mix) synthesis and that in chemically derived lead zirconate titanate ceramics are discussed.

Bel Hadj Tahar, Radhouane; Bel Hadj Tahar, Noureddine; Ben Salah, Abdelhamid

2007-09-01

105

Piezoelectric ceramic (PZT) modulates axonal guidance growth of rat cortical neurons via RhoA, Rac1, and Cdc42 pathways.  

PubMed

Electrical stimulation is critical for axonal connection, which can stimulate axonal migration and deformation to promote axonal growth in the nervous system. Netrin-1, an axonal guidance cue, can also promote axonal guidance growth, but the molecular mechanism of axonal guidance growth under indirect electric stimulation is still unknown. We investigated the molecular mechanism of axonal guidance growth under piezoelectric ceramic lead zirconate titanate (PZT) stimulation in the primary cultured cortical neurons. PZT induced marked axonal elongation. Moreover, PZT activated the excitatory postsynaptic currents (EPSCs) by increasing the frequency and amplitude of EPSCs of the cortical neurons in patch clamp assay. PZT downregulated the expression of Netrin-1 and its receptor Deleted in Colorectal Cancer (DCC). Rho GTPase signaling is involved in interactions of Netrin-1 and DCC. PZT activated RhoA. Dramatic decrease of Cdc42 and Rac1 was also observed after PZT treatment. RhoA inhibitor Clostridium botulinum C3 exoenzyme (C3-Exo) prevented the PZT-induced downregulation of Netrin-1 and DCC. We suggest that PZT can promote axonal guidance growth by downregulation of Netrin-1 and DCC to mediate axonal repulsive responses via the Rho GTPase signaling pathway. Obviously, piezoelectric materials may provide a new approach for axonal recovery and be beneficial for clinical therapy in the future. PMID:24203571

Wen, Jianqiang; Liu, Meili

2014-03-01

106

Identical scaling behavior of saturated dynamic hysteresis in rhombohedral lead zirconate titanate bulk ceramics  

NASA Astrophysics Data System (ADS)

The scaling behaviors of dynamic hysteresis were investigated in serial rhombohedral Nb-doped Pb(Zr1-xTix)O3 (PZT) bulk ceramics as a function of frequency (f) and field amplitude (E0). Three distinct regions were plotted including linear loops, minor loops, and saturated loops with an increase of E0. When the external fields were over ˜1.5 times of coercive field (Ec), the scaling relations of saturated loops for these PZT ceramics could be expressed with an identical form as hysteresis area ?A? ? f 0.01E00.10, which indicated that similar ferroelectric systems with different compositions could display a uniform scaling law under high-E0 and low-f regions.

Chen, Xuefeng; Dong, Xianlin; Zhou, Zhiyong; Wang, Junxia; Cao, Fei; Wang, Genshui; Zhang, Hongling

2013-12-01

107

Short-circuit photocurrent in epitaxial lead zirconate-titanate thin films  

NASA Astrophysics Data System (ADS)

Photovoltaic properties of the metal-ferroelectric-metal structures, having SrRuO3 metal oxide electrodes and Pb(Zr ,Ti)O3 (PZT) as ferroelectric layer, are investigated by the short-circuit photocurrent (SC-PHC) in the 200-800nm wavelength domain. The band-gap dependence on the Zr content was determined from the spectral distribution of the SC-PHC signal. It was found that the band-gap value increases linearly with the Zr content, from about 3.9eV to about 4.4eV. It is shown that the sign and the magnitude of the signal depend on the internal bias and on the spontaneous polarization direction and value. The photocurrent describes a hysteresis loop similar to that of the ferroelectric polarization and can be used as a nondestructive readout of the nonvolatile memories based on PZT films. The existence of a significant SC-PHC signal at wavelengths corresponding to subgap energies is attributed to the presence of charged, deep levels in the forbidden band. It is also shown that the epitaxial PZT films have the potential for solid-state UV detectors, with current responsivity as high as 1mA/W. The results are not entirely consistent with a bulk photovoltaic effect and are discussed in the frame of a Schottky barrier model for the metal-ferroelectric interface.

Pintilie, L.; Vrejoiu, I.; Le Rhun, G.; Alexe, M.

2007-03-01

108

Structure and properties at the ferroelectric/electrode interface between lead zirconate titanate and copper  

SciTech Connect

In advanced actuator systems, ferroelectric ceramics are usually made into multilayered stacks to obtain optimum performance. This is done by interlacing noble metals (such as Pt/Pd) with ceramic green sheet and cofiring. The present study proposes an alternative, more economic electrode. Copper has been successfully diffusion bonded to several PZT-based ferroelectric ceramics in a multilayer configuration. The microstructure and the relevant physical properties of the interfaces have been investigated. This has been achieved by using microscopy, as well as by mechanical and electrical characterization. These studies indicated that no reaction product forms at the interface and, furthermore, that the interface exhibits good cohesion.

Cao, H.C.; De Graef, M.; Evans, A.G. (Univ. of California, Santa Barbara, CA (United States). Materials Dept.)

1993-12-01

109

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

SciTech Connect

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.

Zhu, M. M. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Du, Z. H.; Ma, J. [Temasek Laboratories, Nanyang Technological University, Singapore 637553 (Singapore)

2010-12-01

110

A Reusable PZT Transducer for Monitoring Initial Hydration and Structural Health of Concrete  

PubMed Central

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

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

2010-01-01

111

Local damage detection for steel rebar by impedance measurements of PZT sensors  

NASA Astrophysics Data System (ADS)

Steel rebar is the most employed reinforcements in concrete structures and is subjected to damage due to environmental factors. Therefore it is meaningful to develop suitable non-destructive damage detection methods for steel rebar in engineering structures. Lead Zirconate Titanate (PZT) is one of the most effective types of piezoelectric material, and it has been widely used both sensors and transducers for the structural health monitoring (SHM) of engineering structures. Based on the coupling effect of PZT patches surface-bonded on a structural member, the electromechanical impedance (EMI) based structural damage detection has been employed to detect local damage of civil engineering structures. This paper presents the results of the experimental study on the EMI based damage detection for steel rebar specimens under different damage scenarios by analyzing the changes in the piezoelectric admittance spectrum of PZT patches surface-bonded on the steel rebar specimens. A damage index called the root mean square deviation of admittance (RMSDD) is employed to evaluate the extent of damage of the steel beam. Based on the analysis on the relationship between the damage index and the distance of the PZT sensor from the damage, the sensitivity of the PZT sensors and their sensing region is discussed. The results shows that the location and level of the damages could be quantitatively identified by converting the admittance measurements into the scalar damage index.

Kuang, Juan; Xu, Bin

2012-04-01

112

Depolarization and Electrical Response of Porous PZT 95/5 Ferroelectric Ceramics under Shock Wave Compression  

NASA Astrophysics Data System (ADS)

The release of bound charges by shock wave loading of poled lead zirconate titanate (PZT 95/5) ferroelectric ceramics can result in a high-power electrical energy output. In this study, a theoretical formulation describing the depolarization and electrical response of porous PZT 95/5 ceramics in the normal mode to shock wave compression loading perpendicular to the polarization direction is developed. The depoling process in porous poled PZT 95/5 ceramics is analyzed by using a parallel circuit consisting of a current source, capacitance, conductance and a circuit load. This modeling takes the effects of porosity on wave velocity and remanent polarization and dielectric constant into account, and the effects of variations in dielectric constant and conductivity in the shocked region are assessed. The output current characteristics of porous PZT 95/5 ceramics under short-circuit and resistive load conditions are analyzed and compared with the experiment, with the results showing that theoretical predictions taking into consideration the porosity of ferroelectric ceramics are in close agreement with the experimentally measured electrical response of porous PZT 95/5 under shock wave compression loading.

Wang, Zhi-Zhu; Jiang, Yi-Xuan; Zhang, Pan; Wang, Xing-Zhe; He, Hong-Liang

2014-07-01

113

Scaling and disorder analysis of local I-V curves from ferroelectric thin films of lead zirconate titanate.  

PubMed

Differential analysis of current-voltage characteristics, obtained on the surface of epitaxial films of ferroelectric lead zirconate titanate (Pb(Zr(0.2)Ti(0.8))O(3)) using scanning probe microscopy, was combined with spatially resolved mapping of variations in local conductance to differentiate between candidate mechanisms of local electronic transport and the origin of disorder. Within the assumed approximations, electron transport was inferred to be determined by two mechanisms depending on the magnitude of applied bias, with the low-bias range dominated by the trap-assisted Fowler-Nordheim tunneling through the interface and the high-bias range limited by the hopping conduction through the bulk. Phenomenological analysis of the I-V curves has further revealed that the transition between the low- and high-bias regimes is manifested both in the strength of variations within the I-V curves sampled across the surface, as well as the spatial distribution of conductance. Spatial variations were concluded to originate primarily from the heterogeneity of the interfacial electronic barrier height with an additional small contribution from random changes in the tip-contact geometry. PMID:21572199

Maksymovych, Peter; Pan, Minghu; Yu, Pu; Ramesh, Ramamoorthy; Baddorf, Arthur P; Kalinin, Sergei V

2011-06-24

114

Effects of Polarization on Mechanical Properties of Lead Zirconate Titanate Ceramics Evaluated by Modified Small Punch Tests  

NASA Astrophysics Data System (ADS)

Pb(Zr,Ti)O3 (PZT) ceramics were prepared by the conventional mixed oxide method, and the strength of the resultant PZT ceramics was evaluated using modified small punch (MSP) tests. Load-displacement curve test results showed that the crack-initiation and fracture strengths of PZT ceramics decreased after polarization. The effect of the polarization accelerated the fatigue properties of PZT ceramics. Scanning electron microscopy (SEM) results showed that microcracks were formed before the maximum load in the MSP test, and the first load drop corresponded to crack initiation.

Deng, Qihuang; Fan, Yuchi; Wang, Lianjun; Xiong, Zhi; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong; Kawasaki, Akira; Jiang, Wan

2012-01-01

115

Ferroelectric/Ferroelastic domain wall motion in dense and porous tetragonal lead zirconate titanate films.  

PubMed

Direct evidence of ferroelectric/ferroelastic domain reorientation is shown in Pb(Zr0.30Ti0.70)O3 (PZT30/70) thin films clamped to a rigid silicon substrate using in situ synchrotron X-ray diffraction during application of electric fields. Both dense films and films with 3 to 4 vol% porosity were measured. On application of electric fields exceeding the coercive field, it is shown that the porous films exhibit a greater volume fraction of ferroelastic domain reorientation (approximately 12 vol% of domains reorient at 3 times the coercive field, Ec) relative to the dense films (~3.5 vol% at 3Ec). Furthermore, the volume fraction of domain reorientation significantly exceeded that predicted by linear mixing rules. The high response of domain reorientation in porous films is discussed in the context of two mechanisms: local enhancement of the electric field near the pores and a reduction of substrate clamping resulting from the lowering of the film stiffness as a result of the porosity. Similar measurements during weak-field (subcoercive) amplitudes showed 0.6% volume fraction of domains reoriented for the porous films, which demonstrates that extrinsic effects contribute to the dielectric and piezoelectric properties. PMID:25585389

Johnson-Wilke, Raegan L; Wilke, Rudeger H T; Wallace, Margeaux; Rajashekhar, Adarsh; Esteves, Giovanni; Merritt, Zachary; Jones, Jacob L; Trolier-McKinstry, Susan

2015-01-01

116

Densification, crystallization, and electrical properties of lead zirconate titanate glass-ceramics.  

PubMed

Piezoelectric glass-ceramics in the lead zirconate titanato-lead silicate system were developed. SiO(2) was required for glass formability, and excess PbO allowed low temperature processing. The amounts of those constituents were limited by the optimization of the piezoelectric properties. Only a small region of compositions in this system yielded the desired combination of glass formability, crystallization and densification behavior, and resulting piezoelectric properties. Selected compositions were melted and roller quenched to form glass ribbon, then milled into glass powder. Pressed glass powder densified to closed porosity at 850 degrees C with piezoelectric d(33 ) and g(33) coefficients of 26 pC/N and 33x10(-3 ) Vm/N. The low temperature sintering behavior of these ferroelectric glass-ceramics provides the possibility of incorporating a piezoelectric material as a sensor or actuator in thick film circuits or low-fire multilayer packages. PMID:18238613

Houng, B; Kim, C Y; Haun, M J

2000-01-01

117

Dielectric functions and electronic band structure of lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

We measure pseudodielectric functions in the visible-deep ultraviolet spectral range of Pb(ZrxTi1-x)O3 (x=0.2,0.56,0.82) (PZT), Pb0.98Nb0.04(Zr0.2Ti0.8)0.96O3, Pb0.91La0.09(Zr0.65Ti0.35)0.98O3, and Pb0.85La0.15Ti0.96O3 films grown on platinized silicon substrates using a sol-gel method and on (0001) sapphire using a radio-frequency sputtering method. Using a parametric optical constant model, we estimate the dielectric functions (?) of the perovskite oxide thin films. Taking the second derivative of the fitted layer dielectric functions and using the standard critical-point model, we determine the parameters of the critical points. In the second derivative spectra, the lowest band-gap energy peak near 4 eV is fitted as a double peak for annealed PZTs due to the perovskite phase. As-grown PZTs have mainly pyrochlore phase and the lowest band-gap peak is fitted as a single peak. We also examine the effect of dopants La and Nb, which substitute at Pb and Zr (Ti) sites, respectively. We found three band gaps Ea (~3.9 eV), Eb (~4.5 eV), and Ec (~6.5 eV) in the order of increasing energy. The Ea and Eb band-gap energies were not sensitive to Zr composition. We discuss the change of critical-point parameters for PZTs in comparison to the band-structure calculations based on local-density approximation. The near constancy of the lowest band-gap energy independent of Zr composition is consistent with the band-structure calculations.

Lee, Hosun; Kang, Youn Seon; Cho, Sang-Jun; Xiao, Bo; Morkoç, Hadis; Kang, Tae Dong; Lee, Ghil Soo; Li, Jingbo; Wei, Su-Huai; Snyder, P. G.; Evans, J. T.

2005-11-01

118

Effects of acetylacetone additions on PZT thin film processing  

SciTech Connect

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.

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

1995-02-01

119

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

PubMed

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

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

2014-09-01

120

Fabrication and Evaluation of One-Axis Oriented Lead Zirconate Titanate Films Using Metal-Oxide Nanosheet Interface Layer  

NASA Astrophysics Data System (ADS)

Nanosheet Ca2Nb3O20 (ns-CN) layers with pseudo-perovskite-type crystal configuration were applied on the surface of polycrystalline metal substrates to achieve preferential crystal orientation of Pb(Zr,Ti)O3 (PZT) films for the purpose of enhanced ferroelectricity comparable to that of epitaxial thin films. PZT films with tetragonal symmetry (Zr/Ti=0.40:0.60) were fabricated by chemical solution deposition (CSD) on ns-CN-buffered Inconel 625 and SUS 316L substrates, while ns-CN was applied on the the substrates by dip-coating. The preferential crystal growth on the ns-CN layer can be achieved by favorable lattice matching between (001)/(100)PZT and (001)ns-CN planes. The degree of (001) orientation was increased for PZT films on ns-CN/Inconel 625 and ns-CN/SUS 316L substrates, whereas randomly-oriented PZT films with a lower degree of (001) orientation were grown on bare and Inconel 625 films. Enhanced remanent polarization of 60 µC/cm2 was confirmed for the PZT films on ns-CN/metal substrates, ascribed to the preferential alignment of the polar [001] axis normal to the substrate surface, although it also suffered from higher coercive field above 500 kV/cm caused by PZT/metal interfacial reaction.

Minemura, Yoshiki; Nagasaka, Kohei; Kiguchi, Takanori; Konno, Toyohiko J.; Funakubo, Hiroshi; Uchida, Hiroshi

2013-09-01

121

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

122

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

NASA Astrophysics Data System (ADS)

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).

Banerjee, Sankha

123

Effects of solution precursor nature on sol-gel derived PZT thin film crystallization behavior and properties  

SciTech Connect

In fabricating lead zirconate titanate (PZT) films for nonvolatile memories and decoupling capacitors, various deposition methods have been investigated. Each can produce films with acceptable dielectric and ferroelectric properties, but sol-gel methods offer excellent control of film stoichiometry and coating uniformity. The sol-gel approaches for PZT film fabrication fall into two categories: processes that use 2-methoxyethanol as a solvent, and processes that use chelating agents, such as acetic acid, for reducing the hydrolysis sensitivity of the alkoxide compounds. Due to concerns about the toxicity of 2-methoxyethanol, we have concentrated on the second category. It was found that, in addition to reducing the hydrolysis sensitivity, the chelating agents serves to define the processing behavior of the films: film consolidation after deposition and densification and crystallization during heat treatment. This paper discusses the relations between precursor structure (reactions between chelating agents and the metal alkoxide starting reagents) and film consolidation, densification, and crystallization.

Schwartz, R.W.; DaSalla, R.S.

1995-09-01

124

PZT Thin-Film Micro Probe Device with Dual Top Electrodes  

NASA Astrophysics Data System (ADS)

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

Luo, Chuan

125

Titan  

NASA Technical Reports Server (NTRS)

This narrow-angle camera image of Titan was taken through the Clear filter from a distance of 0.9 million km on 25 August 1981. With a phase angle of 155 degrees, the thick atmosphere can be seen illuminated completely around the disk. A distinct upper haze layer is present over much of the circumference of the disk. JPL managed the Voyager Project for NASA's Office of Space Science.

2000-01-01

126

Miniature cryogenic valves for a Titan Lake sampling system  

NASA Astrophysics Data System (ADS)

The Cassini mission has revealed Titan to be one of the most Earthlike worlds in the Solar System complete with many of the same surface features including lakes, river channels, basins, and dunes. But unlike Earth, the materials and fluids on Titan are composed of cryogenic organic compounds with lakes of liquid methane and ethane. One of the potential mission concepts to explore Titan is to land a floating platform on one of the Titan Lakes and determine the local lake chemistry. In order to accomplish this within the expected mass volume and power budgets there is a need to pursue the development for a low power lightweight cryogenic valves which can be used along with vacuum lines to sample lake liquid and to distribute to various instruments aboard the Lander. To meet this need we have initiated the development of low power cryogenic valves and actuators based on a single crystal piezoelectric flextensional stacks produced by TRS ceramics Inc. Since the origin of such high electromechanical properties of Relaxor-PT single crystals is due to the polarization rotation effect, (i.e., intrinsic contributions), the strain per volt decrease at cryogenic temperatures is much lower than in standard Lead Zirconate Titanate (PZT) ceramics. This makes them promising candidates for cryogenic actuators with regards to the stroke for a given voltage. This paper will present our Titan Lake Sampling and Sample Handling system design and the development of small cryogenic piezoelectric valves developed to meet the system specifications.

Sherrit, Stewart; Zimmerman, Wayne; Takano, Nobuyuki; Avellar, Louisa

2014-04-01

127

Cavitation sensor with hydrothermally synthesized lead zirconate titanate polycrystalline film deposited on cylindrical titanium pipe: Estimation of acoustic cavitation field and basic characteristics of cavitation sensor  

NASA Astrophysics Data System (ADS)

We have developed a small cavitation sensor by deposition of hydrothermally synthesized lead zirconate titanate polycrystalline film onto the outer surface of a hollow cylindrical titanium pipe. The spatial distribution of acoustic cavitation generated in the vessel of a 150 kHz sonoreactor was measured by using the broadband integrated voltage (BIV) calculated from the output signal of the cavitation sensor. A spatial distribution similar to the sonochemical luminescence pattern could be observed in the measured BIV results. We found that our fabricated cavitation sensor could measure the spatial distribution of acoustic cavitation in a high-intensity ultrasound field for a period exceeding 150 h without damage. We also measured the spatial distribution and directivity of the receiving sensitivity for characterization of the sensor. The measured results suggest that the BIV and cavitation signal included in the output signal of the cavitation sensor are a consequence of the acoustic cavitation generated in the sensor's cylindrical hollow.

Shiiba, Michihisa; Uchida, Takeyoshi; Kikuchi, Tsuneo; Ishikawa, Mutzuo; Kawashima, Norimichi; Kurosawa, Minoru; Takeuchi, Shinichi

2012-05-01

128

Interface magnetoelectric effect in the layered heterostructures with Co layers on the polished and ion-beam planarized ceramic PZT substrates  

NASA Astrophysics Data System (ADS)

The low-frequency room temperature interface magnetoelectric (ME) effect was observed in the layered heterostructures comprising the ferromagnetic (FM) Co layers and ferroelectric (FE) ceramic substrates on the base of lead zirconate titanate PbZr0.45Ti0.55O3 (PZT). The Co films 1-12 ?m in thickness were deposited by ion-beam sputtering/deposition technics onto the 400 ?m PZT substrates. Results of X-ray, magnetic and ME experiments have shown the existence of ME effect in Co/PZT/Co and (Co/PZT/Co)3 heterostructures obtained by the above mentioned techniques being independent on ferromagnetic/ferroelectric interface roughness. The values of ME voltage coefficient in heterostructures with ion-beam planarized PZT surfaces are much higher than that in heterostructures with mechanochemically polished ceramic substrate surfaces. The heterostructures possess ME effect of the same order as those obtained by means of the mechanical bonding of FM and FE sheets with organic binders and have the typical ME hysteresis curves. The structures obtained are perspective for application as energy-independent elements in magnetic field sensors and magnetic memory.

Stognij, Alexandre I.; Novitskii, Nickolaj; Poddubnaya, Natalia; Sharko, Sergei; Ketsko, Valerij; Mikhailov, Vladimir; Dyakonov, Vladimir; Szymczak, Henryk

2015-01-01

129

Large Stroke Vertical PZT Microactuator With High-Speed Rotational Scanning  

PubMed Central

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

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

2014-01-01

130

Damage Evaluation Based on a Wave Energy Flow Map Using Multiple PZT Sensors  

PubMed Central

A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti's reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to construct the WEF map when waves propagate through an inspection region, and multiple lead zirconate titanate (PZT) sensors were employed to improve inspection reliability. Various damages in aluminum and carbon fiber reinforced plastic laminated plates were experimentally and numerically evaluated to validate this technique. The results show that it can effectively evaluate the shape and size of damage from wave field variations around the damage in the WEF map. PMID:24463430

Liu, Yaolu; Hu, Ning; Xu, Hong; Yuan, Weifeng; Yan, Cheng; Li, Yuan; Goda, Riu; Alamusi; Qiu, Jinhao; Ning, Huiming; Wu, Liangke

2014-01-01

131

Development of a thick film PZT foil sensor for use in structural health monitoring applications.  

PubMed

Acoustic emission (AE) monitoring is a technique of growing interest in the field of nondestructive testing (NDT). The use of AE devices to monitor the health of structural components is currently limited by the cost of AE equipment, which prohibits the permanent placement of AE devices on structures for the purposes of continuous monitoring and the monitoring of areas with limited access. Micro electromechanical systems (MEMS) can provide solutions to these problems. We present the manufacture of a 4.4-?m-thick lead zirconate titanate (PZT) film on a 110-?m-thick titanium foil substrate for use as an AE sensor. The thick-film sensor is benchmarked against commercially available AE sensors in static and dynamic monitoring applications. The thick-film AE device is found to perform well in the detection of AE in static applications. A low signal-to-noise ratio is found to prohibit the detection of AE in a dynamic application. PMID:23357911

Pickwell, Andrew J; Dorey, Robert A; Mba, David

2013-02-01

132

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

SciTech Connect

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.

Daniel, L., E-mail: laurent.daniel@u-psud.fr [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); LGEP (CNRS UMR8507, SUPELEC, UPMC, Univ Paris-Sud), 91192 Gif sur Yvette cedex (France); Hall, D. A.; Withers, P. J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Webber, K. G. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); King, A. [European Synchrotron Radiation Facility (ESRF), 6 rue J. Horowitz, 38043 Grenoble (France); Synchrotron SOLEIL, BP 48, 91192 Gif sur Yvette cedex (France)

2014-05-07

133

The effects of large AC electric fields on the properties of ferroelectric lead zirconate titanate thin films  

NASA Astrophysics Data System (ADS)

The initial motivation of the research presented here was to understand some novel phenomena reported in compositionally graded ferroelectric films. The phenomenon of primary interest was the translation of ferroelectric hysteresis loops along what is normally regarded as the polarization axis, which was interpreted as a polarization offset with anamolously large and unphysical values. The fabrication of compositionally graded Pb(Zr,Ti)O 3 (PZT) thin films is presented along with the observation of hysteresis loop translations. These hysteresis loop translations were found to be due to a dc voltage offset which develops on the sample capacitor. In addition, these voltage offsets were found to be sensitive to the oxygen partial pressure of the atmosphere in which the films were situated. Similar oxygen dependent voltage offsets were observed for non-graded PZT films. It is proposed that the observed voltage offsets are ultimately the result of a redistribution of oxygen vacancies at the film surface. This hypothesis is supported by the observation of oxygen dependent voltage offsets in yttria stabilized zirconia films. Two models are proposed which attempt to explain how a redistribution of oxygen vacancies might result in the observed voltage offsets. These models are presented along with experimental results which offer insights into their validity. Finally, a course for future studies is recommended.

Brazier, Mark R.

134

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

PubMed

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

Sohn, Hoon; Kim, Seuno Bum

2010-01-01

135

PZT-based active damage detection techniques for steel bridge components  

NASA Astrophysics Data System (ADS)

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.

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

2006-08-01

136

Thickness dependence of electrical properties of PZT films deposited on metal substrates by laser-assisted aerosol deposition.  

PubMed

Dependence of electrical properties-dielectric, ferroelectric, and piezoelectric properties-on film thickness was studied for lead-zirconate titanate (PZT) thick films directly deposited onto stainless-steel (SUS) substrates in actuator devices by using a carbon dioxide (CO(2) ), laser assisted aerosol deposition technique. Optical spectroscopic analysis data and laser irradiation experiments revealed that absorption at a given wavelength by the film increased with increasing film thickness. Dielectric constant epsilon, remanent polarization value P(r), and coercive field strength E(c) of PZT films directly deposited onto a SUS-based piezoelectric actuator substrate annealed by CO(2) laser irradiation at 850 degrees C improved with increasing film thickness, and for films thicker than 25 microm, epsilon 800, P(r) 40 microC/cm(2), and E(c) 45 kV/cm. In contrast, the displacement of the SUS-based actuator with the laser-annealed PZT thick film decreased with increasing film thickness. PMID:18519203

Baba, S; Tsuda, H; Akedo, J

2008-05-01

137

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

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.

Zhao, Hua; Zhang, Kun; Xu, Long; Sun, Fankui; Zhang, Jingwen, E-mail: jingwenz@gmail.com [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Chen, Xuesheng [Department of Physics and Astronomy, Wheaton College, Norton Massachusetts 02766 (United States); Li, Kewen K. [Boston Applied Technologies, Inc., Woburn, Massachusetts 01801 (United States)

2014-02-21

138

Nonlinear magnetoelectric effect in PZT/Terfenol-D nanobilayer on a substrate with surface stress  

NASA Astrophysics Data System (ADS)

Based on a linear piezoelectric constitutive relation and a nonlinear magnetostrictive constitutive relation, a nonlinear magnetoelectric (ME) effect model for lead zirconate titanate (PZT)/Terfenol-D nanobilayer on a substrate has been developed. In this study, the nonlinear ME coefficients at bending mode for two cases (without surface stress and with surface stress) are calculated by using Gurtin-Murdoch theory. The difference between two cases and the influence of residual surface tension are discussed. At the same time, the clamping effect of the substrate on ME effect is studied by altering the thickness ratio of the substrate and selecting different substrate materials. The influences of frequency of the magnetic field, PZT volume fraction on the ME effect are investigated, respectively. Finally, the dependence of ME effect on pre-stress is presented. The results show that for the nanobilayer, both the residual surface tension and surface stress have non-ignored effects on the ME effect. Besides, the resonant frequency of the nanobilayer is very low at the bending mode, which can be enhanced by increasing the thickness ratio of the substrate. Also, the substrate can weaken the ME effect due to the clamping effect, and a more soft substrate material should be selected for large ME effect. In addition, pre-stress plays an important role in the nonlinear ME coupling effect of the model developed.

Shi, Yang; Niu, Longfei; Gao, Yuanwen

2014-07-01

139

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

NASA Astrophysics Data System (ADS)

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.

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

2012-01-01

140

Synthesis and characterization of thick PZT films via sol-gel dip coating method  

NASA Astrophysics Data System (ADS)

Thick films of lead zirconate titanate (PZT) offer possibilities for micro-electro-mechanical systems such as high frequency ultrasonic transducers. In this paper, crack-free thick films of PZT have been prepared up to 45 ?m thickness via modified sol-gel dip coating method. In this procedure, acetic acid-alcoholic based sol is used by applying diethanolamine (DEA) and deionized water as additives. The effects of DEA and water on the crystal structure and surface morphology of the films are investigated. The mechanisms of acetic acid and DEA complexations are introduced by using FTIR spectrometer which illustrates suitable substitution of complexing agents with alkoxide groups. DEA/(Ti + Zr) = 0.5 or water/(Ti + Zr) = 0.5 are determined as the optimum molar ratio of additives, which lead to the formation of almost pure perovskite phase with the tetragonal lattice parameters of ct = 4.16 ? and at = 4.02 ? and a distortion of 2%. Values of remanent polarization and dielectric constant of 7.8 ?C cm-2 and 1630 were obtained for 45 ?m thick films, respectively.

Shakeri, Amid; Abdizadeh, Hossein; Golobostanfard, Mohammad Reza

2014-09-01

141

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

SciTech Connect

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.

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

2009-01-01

142

Fatigue response of a PZT multilayer actuator under high-field electric cycling with mechanical preload  

NASA Astrophysics Data System (ADS)

An electric fatigue test system was developed for evaluating the reliability of piezoelectric actuators with a mechanical loading capability. Fatigue responses of a lead zirconate titanate (PZT) multilayer actuator with a platethrough electrode configuration were studied under an electric field (1.7 times that of the coercive field of PZT material) and a concurrent mechanical preload (30.0 MPa). A total of 109 cycles was carried out. Variations in charge density and mechanical strain under the 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 using fast Fourier transformation. Both the dielectric and the piezoelectric coefficients exhibited a monotonic decrease prior to 2.86×108 cycles under certain preloading conditions, and then fluctuated. Both the dielectric loss tangent and the piezoelectric loss tangent also fluctuated after a decrease. The results are interpreted and discussed with respect to domain wall activities, microdefects, and other anomalies.

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

2009-01-01

143

Effect of Zr\\/Ti Ratio in Targets on Electrical Properties of Lead Zirconate Titanate Thin Films Derived by Pulsed Laser Deposition on Template Layer  

Microsoft Academic Search

Using various targets of Pb(ZrxTi1-x)O3 (PZT) with Zr\\/Ti ratios of 70\\/30, 58\\/42, 52\\/48, 45\\/55 and 30\\/70, PZT thin films were prepared by pulsed laser deposition on Pt\\/Ti\\/SiO2\\/Si(100) substrates with a template layer derived by the sol-gel process. The structure and crystalline phases of the PZT films relative to the Zr\\/Ti ratio were investigated by X-ray diffraction analysis. The effect of

Zhan-Jie Wang; Isao Karibe; Li Jun Yan; Hiroyuki Kokawa; Ryutaro Maeda

2002-01-01

144

Optimization of a 0.69PZT-0.31PZNN thick film by controlling slurry viscosity and tape-casting blade height  

NASA Astrophysics Data System (ADS)

We investigated how the viscosities of piezoelectric lead zirconate titanate/lead zirconate nickel niobate (PZT-PZNN) slurry samples affect the laminated-film densities based on various conditions of degassing time for 0, 30, and 60 min. PZT-PZNN slurries with different viscosities were tape casted into green sheets by adjusting the comma blade height to 100, 200, 300, 400, and 500 ?m. As a result the slurry viscosity linearly increased with increasing slurry degassing time, and the thickness of the green sheet increased with increasing comma blade height. The density and the dielectric properties of piezoelectric ceramic films with the same thicknesses, but composed of different numbers of layers, were compared. The laminated-film density and the dielectric property d33 × g33 increased with decreasing number of laminated layers. However, when the viscosity of the slurry was too high (degassing time > 60 min) and the comma blade height was too high (comma blade height > 300 ?m), the tape-casted green sheet was too thick to have enough time to dry. By controlling the slurry viscosity by adjusting the degassing time and the comma blade height, we were able to optimize the thickness of the green sheet in a tape-casting. The optimal green sheet thickness was < 70 ?m, and the number of sheets laminated should be minimized to increase the film's density and dielectric constant.

Song, Daniel; Woo, Min Sik; Ahn, Jung Hwan; Sung, Tae Hyun; Kim, Kyoung Bum

2014-12-01

145

Ion-beam sputtering deposition and magnetoelectric properties of layered heterostructures (FM/PZT/FM)n, where FM - Co or Ni78Fe22  

NASA Astrophysics Data System (ADS)

Magnetoelectric properties of layered heterostructures (FM/PZT/FM)n (n? 3) obtained by ion-beam sputtering deposition of ferromagnetic metal (FM), where FM is the cobalt (Co) or permalloy Ni78Fe22, onto ferroelectric ceramic based on lead zirconate titanate (PZT) have been studied. The polished ferroelectric plates in thickness from 400 to 20 ?m were subjected to finished treatment by ion-beam sputtering. After plasma activation they were covered by the ferromagnetic films from 1 to 6 ?m in thickness. Enhanced characteristics of these structures were reached by means of both the thickness optimization of ferroelectric and ferromagnetic layers and obtaining of ferromagnetic/ferroelectric interfaces being free from defects and foreign impurities. Assuming on the basis of analysis of elastic stresses in the ferromagnetic film that the magnetoelectric effect forms within ferromagnetic/ferroelectric interface, the structures with 2-3 ferromagnetic layers were obtained. In layered heterostructure (Py/PZT/Py)3, the optimal thickness of ferromagnetic film was 2 ?m, and outer and inner ferroelectric layers had 20 ?m and 80 ?m in thickness, respectively. For such structure the maximal magnetoelectric voltage coefficient of 250 mV/(cm Oe) was reached at a frequency 100 Hz in magnetic field of 0.25 T at room temperature. The structures studied can serve as energy-independent elements detecting the change of magnetic or electric fields in electronic devices based on magnetoelectric effect.

Stognij, Alexander; Novitskii, Nikolai; Sazanovich, Andrei; Poddubnaya, Nadezhda; Sharko, Sergei; Mikhailov, Vladimir; Nizhankovski, Viktor; Dyakonov, Vladimir; Szymczak, Henryk

2013-08-01

146

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

E-print Network

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 ...

AlSaeed, Abdulelah (Abdulelah Ibrahim)

2012-01-01

147

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

PubMed Central

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

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

2007-01-01

148

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

PubMed

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

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

2007-02-01

149

Effect of Zr\\/Ti Ratio on Microstructure and Electrical Properties of Lead Zirconate Titanate Thin Films Derived by Pulsed Laser Deposition  

Microsoft Academic Search

PZT films were fabricated using various targets of Pb(ZrxTi1 - x)O3 with Zr\\/Ti ratios of 70\\/30, 58\\/42, 52\\/48, 45\\/55 and 30\\/70, and with excess PbO of 20 wt% on Pt\\/Ti\\/SiO2\\/Si(100) substrates. The rosette structure was observed in the films derived from the target with a Zr\\/Ti ratio of 70\\/30 and disappeared with increasing titanium composition. The observations on surface and

Zhanxy Jie Wang; Yuki Aoki; Hiroyuki Kokawa; Masaaki Ichiki; Ryutaro Maeda

2004-01-01

150

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

PubMed Central

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

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

2014-01-01

151

Sol-gel synthesis of high-quality SrRuO{sub 3} thin film electrodes suppressing the formation of detrimental RuO{sub 2} and the dielectric properties of integrated lead lanthanum zirconate titanate films.  

SciTech Connect

A facile solution chemistry is demonstrated to fabricate high-quality polycrystalline strontium ruthenium oxide (SrRuO{sub 3}) thin film electrodes on silicon substrates suppressing the formation of undesired ruthenium oxide (RuO{sub 2}) for the deposition of dielectric and ferroelectric materials like lead lanthanum zirconate titanate (PLZT). The robust, highly crystalline SrRuO{sub 3} film fabrication process does not favor the formation of RuO{sub 2} because of molecular level modification of the precursors possessing analogous melting points, yielding homogeneous films. This chemistry is further understood and complemented by kinetic and thermodynamic analysis of the DTA data under nonisothermal conditions, with which the activation energies to form RuO{sub 2} and SrRuO{sub 3} were calculated to be 156 {+-} 17 and 96 {+-} 10 kJ/mol, respectively. The room-temperature resistivity of the SrRuO{sub 3} film was measured to be 850 {+-} 50 {mu}{Omega} cm on silicon (100) substrates. The dielectric properties of sol-gel-derived PLZT thin film capacitors on polycrystalline SrRuO{sub 3} electrodes were also measured to illustrate the high quality of the formed SrRuO{sub 3} bottom electrode. These results have broad implications for the expanded use of these conductive oxide electrodes in many applications that require low thermal budgets. The PLZT (8/52/48) films exhibited well-defined hysteresis loops with remanent polarization of {approx}10.5 {micro}C/cm{sup 2}, dielectric constant of >1450, dielectric loss of <0.06, and leakage current density of {approx}3.8 x 10{sup -8} A/cm{sup 2}. These dielectric properties are similar to those of PLZT on platinized silicon, indicating the high quality of the bottom conductive oxide layer. In addition, the PLZT capacitors were essentially fatigue free for >1 x 10{sup 9} cycles when deposited over an oxide electrode.

Narayanan, M.; Tong, S.; Koritala, R.; Ma, B.; Pol, V.; Balachandran, U.

2011-01-01

152

A large-scan-angle piezoelectric MEMS optical scanner actuated by a Nb-doped PZT thin film  

NASA Astrophysics Data System (ADS)

Resonant 1D microelectromechanical systems (MEMS) optical scanners actuated by piezoelectric unimorph actuators with a Nb-doped lead zirconate titanate (PNZT) thin film were developed for endoscopic optical coherence tomography (OCT) application. The MEMS scanners were designed as the resonance frequency was less than 125 Hz to obtain enough pixels per frame in OCT images. The device size was within 3.4 mm × 2.5 mm, which is compact enough to be installed in a side-imaging probe with 4 mm inner diameter. The fabrication process started with a silicon-on-insulator wafer, followed by PNZT deposition by the Rf sputtering and Si bulk micromachining process. The fabricated MEMS scanners showed maximum optical scan angles of 146° at 90 Hz, 148° at 124 Hz, 162° at 180 Hz, and 152° at 394 Hz at resonance in atmospheric pressure. Such wide scan angles were obtained by a drive voltage below 1.3 Vpp, ensuring intrinsic safety in in vivo uses. The scanner with the unpoled PNZT film showed three times as large a scan angle as that with a poled PZT films. A swept-source OCT system was constructed using the fabricated MEMS scanner, and cross-sectional images of a fingertip with image widths of 4.6 and 2.3 mm were acquired. In addition, a PNZT-based angle sensor was studied for feedback operation.

Naono, Takayuki; Fujii, Takamichi; Esashi, Masayoshi; Tanaka, Shuji

2014-01-01

153

RMS Titanic  

NSDL National Science Digital Library

RMS Titanic raised a 23- by 14-foot section of the Titanic's outer hull this week. RMS, which has exclusive rights to photograph the Titanic and to possess any items recovered from the wreck, doesn't miss an opportunity to market Titanic-oriented merchandise on their site. Nonetheless, visitors wanting to know more about the Titanic will be interested in the expedition calendar and background information on the Titanic's voyage and the exploration of its remains.

2000-01-01

154

Theoretical model to describe dispersive nonlinear properties of lead zirconatetitanate ceramics  

E-print Network

Theoretical model to describe dispersive nonlinear properties of lead zirconate­titanate ceramics K signals measured in lead zirconate­titanate PZT ceramics suggest the introduction of a revised theoretical

155

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

PubMed

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

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

2014-12-01

156

Titan Meteorology  

NASA Astrophysics Data System (ADS)

Titan’s methane clouds have received much attention since they were first discovered spectroscopically (Griffith et al. 1998). Titan's seasons evolve slowly, and there is growing evidence of a seasonal response in the regions of methane cloud formation (e.g. Rodriguez et al. 2009). A complete, three-dimensional view of Titan’s clouds is possible through the determination of cloud-top heights from Cassini images (e.g., Ádámkovics et al. 2010). Even though Titan’s surface is warmed by very little sunlight, we now know Titan’s methane clouds are convective, evolving through tens of kilometers of altitude on timescales of hours to days with dynamics similar to clouds that appear on Earth (Porco et al. 2005). Cassini ISS has also shown evidence of rain storms on Titan that produce surface accumulation of methane (Turtle et al. 2009). Most recently, Cassini has revealed a 1000-km-scale, arrow-shaped cloud at the equator followed by changes that appear to be evidence of surface precipitation (Turtle et al. 2011b). Individual convective towers simulated with high fidelity indicate that surface convergence of methane humidity and dynamic lifting are required to trigger deep, precipitating convection (e.g. Barth & Rafkin 2010). The global expanses of these cloud outbursts, the evidence for surface precipitation, and the requirement of dynamic convergence and lifting at the surface to trigger deep convection motivate an analysis of storm formation in the context of Titan’s global circulation. I will review our current understanding of Titan’s methane meteorology using Cassini and ground-based observations and, in particular, global circulation model simulations of Titan’s methane cycle. When compared with cloud observations, our simulations indicate an essential role for planetary-scale atmospheric waves in organizing convective storms on large scales (Mitchell et al. 2011). I will end with predictions of Titan’s weather during the upcoming northern hemisphere summer.

Mitchell, Jonathan

2012-04-01

157

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

158

Control of crystallographic texture and surface morphology of Pt/Tio2 templates for enhanced PZT thin film texture.  

PubMed

Optimized processing conditions for Pt/TiO2/SiO2/Si templating electrodes were investigated. These electrodes are used to obtain [111] textured thin film lead zirconate titanate (Pb[ZrxTi1-x ]O3 0 ? x ? 1) (PZT). Titanium deposited by dc magnetron sputtering yields [0001] texture on a thermally oxidized Si wafer. It was found that by optimizing deposition time, pressure, power, and the chamber pre-conditioning, the Ti texture could be maximized while maintaining low surface roughness. When oxidized, titanium yields [100]-oriented rutile. This seed layer has as low as a 4.6% lattice mismatch with [111] Pt; thus, it is possible to achieve strongly oriented [111] Pt. The quality of the orientation and surface roughness of the TiO2 and the Ti directly affect the achievable Pt texture and surface morphology. A transition between optimal crystallographic texture and the smoothest templating surface occurs at approximately 30 nm of original Ti thickness (45 nm TiO2). This corresponds to 0.5 nm (2 nm for TiO2) rms roughness as determined by atomic force microscopy and a full-width at half-maximum (FWHM) of the rocking curve 0002 (200) peak of 5.5/spl degrees/ (3.1/spl degrees/ for TiO2). A Pb[Zr0.52Ti 0.48]O3 layer was deposited and shown to template from the textured Pt electrode, with a maximum [111] Lotgering factor of 87% and a minimum 111 FWHM of 2.4/spl degrees/ at approximately 30 nm of original Ti. PMID:25585390

Fox, Austin J; Drawl, Bill; Fox, Glen R; Gibbons, Brady J; Trolier-McKinstry, Susan

2015-01-01

159

Structural Properties of Ferroelectric Lead(Zirconium0.5,Titanium0.5)Oxygen3 Nanotube Array and Electronic Structure of Lao delta-doped strontium titanate  

NASA Astrophysics Data System (ADS)

In this Dissertation we begin with two introductions on: 1) ferroelectricity and related phenomena, and 2) novel properties of Oxide electronics and the generation of two dimensional electron gas. We then give theoretical background of density functional theory (including LDA+U) and pseudopotentials. The first part of research work is about structural, polarization, and dielectric properties of ferroelectric Lead Zirconate Titanate (PZT) solid solution in the form of a nanotube array, embedded in a matrix medium of different ferroelectric strengths. We use the effective Hamiltonian derived from first-principles and finite-temperature Monte Carlo methods to determine the various properties. We revealed different polarization phases of the system in the absence of an external electric field and explained these properties in microscopic detail. In the second part, we study the effects of compressive biaxial inplane strains on the electronic and structural properties of Lanthanum Oxide delta-doped Strontium Titanate supercell. We use first-principles density functional calculations within the local density approximation including also on-site Coulomb interaction energy. We approached the problem by comparing the band structures, localization of electronic states, and cation-anion displacements of unstrained and strained systems. We found a critical strain above which there are abrupt changes in conduction band dispersions and cation-anion displacements, indicating that inplane biaxial strain can drastically tune the properties of this system, which may have potential technological applications.

Adhikari, Rajendra P.

160

SIAM J. APPL. MATH. c 2006 Society for Industrial and Applied Mathematics Vol. 66, No. 6, pp. 19982026  

E-print Network

accommodate the hysteresis inherent to ferroelectric compounds. Second, these constitutive relations. Introduction. Stage mechanisms employing the ferroelectric material lead zirconate titanate (PZT) have played, PZT actuators are often used to drive the microcantilevers at resonance to achieve the tapping mode

Salapaka, Murti V.

161

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

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.

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

1995-10-01

162

IOP PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER J. Phys.: Condens. Matter 20 (2008) 425206 (4pp) doi:10.1088/0953-8984/20/42/425206  

E-print Network

coupling was reported for a system free of a free of any substrate, i.e., cobalt ferrite on BTO [5 ferrite on lead zirconate titanate (PZT). Both ideal and non-ideal interface coupling are considered so far include ferrite, metals or alloys for the magnetic phase and lead zirconate titanate (PZT

Srinivasan, Gopalan

163

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)

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.

Muchenik Cena, Tomas Ignacio

164

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

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.

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

1999-07-26

165

RMS Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Mr.taylor

2010-04-20

166

The Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Van Vooren, Ms.

2007-12-04

167

RMS TITANIC  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Klooney

2010-04-20

168

Piezoelectric properties of various printed PZT microsystems  

NASA Astrophysics Data System (ADS)

Free-standing PZT thick-films and completely released devices can be interesting for MEMS applications, avoiding the mechanical effect of the substrate on their electromechanical properties. Improvements of the electromechanical properties of free-standing and completely released electroded piezoelectric Au/PZT/Au thick-films with different geometries are studied. They are successfully fabricated thanks to the association of the low-cost screen-printing technology with the sacrificial layer method. Free-standing electroded and completely released PZT thick films appear promising for microsystems applications.

Debéda, Hélène; Favre, Isabelle; Lucat, Claude

2014-11-01

169

Ceramic with zircon coating  

NASA Technical Reports Server (NTRS)

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.

Wang, Hongyu (Inventor)

2003-01-01

170

Zircons are Forever  

NSDL National Science Digital Library

Zircons have been in the news lately because of the recent discovery that the chemical signature of the oldest known zircon crystal (4.4 billion years) suggests that water, and thus conditions for life on Earth, was present then. Geologists at the University of Wisconsin-Madison contributed to a large part of this study. Zircons are Forever is a newly posted feature page on the UW Geology and Geophysics Website. The text describes the basic chemistry of zircon and why it is an important mineral for studies of mantle formation. Particular emphasis is on stable isotope geochemistry. A hyperlinked bibliography leads to abstracts and plots of oxygen isotope values from papers by UW faculty and graduate students. Zircons are Forever adds a little more background to the recent headlines.

171

Molecular Structure of Zircon  

NSDL National Science Digital Library

Zircon (zirconium silicate) was found in Greece and Italy as far back as the 6th Century A.D. Zircon comes from the Persian word "zargun" which means gold-colored. Zircon has been used as a diamond substitute because it resembles diamond in luster and has been mistaken for diamonds by many experienced jewelers, although it is not the same as Cubic Zirconia. It can be brown, red, green, blue, yellow, black, violet, orange and colorless. A typical crystal of zircon is shaped like a tetragonal prism with four sided prisms at each end. Zircon can be found in Laacher Sea, Niedermendig and Germany, and is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, and other countries.

2002-09-06

172

Titanic Research Link  

NSDL National Science Digital Library

Welcome Aboard the Titanic Third Graders! Enjoy your trip into the history of a fatal night. Use the following websites to help answer your research questions: Encyclopedia Titanica Construction Construction Begins Iceberg Inside the RMS Titanic RMS Titanic Inc.-The ShipThe CollisionThe Lure and the LoveTitanic FAQs ...

Law, Miss

2012-01-17

173

Virtual Titanic  

NSDL National Science Digital Library

The recent historical and cinematic fascination with the Titanic proves that the allure of this most famous luxury liner remains unsinkable. The Discovery Channel Online has created a captivating site devoted to images, movies (IPIX, QuickTime), and text describing the ship and its demise. While the site contains historical photos and lithographs of the ship as well as underwater photos and movies from a 1985 submersible mission, the unique contribution of this site is its numerous virtual images of the interior and exterior of the Titanic as well as its movies of the collision and sinking. Developed by Andrew Nelson for a CD-ROM game, the movies include a flyby of the ship, a collision movie, a listing movie, and a three-part series of the sinking. Both flat and "bubble" views of such features as the first-class cabins, the wireless room, and the grand staircase are also included. A talk-back section discusses various theories surrounding the sinking and contains several related links.

174

Epitaxial growth of lead zirconium titanate thin films on Ag buffered Si substrates using rf sputtering  

SciTech Connect

Epitaxial lead zirconium titanate (PZT) (001) thin films with a Pt bottom electrode were deposited by rf sputtering onto Si(001) single crystal substrates with a Ag buffer layer. Both PZT(20/80) and PZT(53/47) samples were shown to consist of a single perovskite phase and to have the (001) orientation. The orientation relationship was determined to be PZT(001)[110](parallel sign)Pt(001)[110](parallel sign)Ag(001)[110](parallel sign)Si(001)[110]. The microstructure of the multilayer was studied using transmission electron microscopy (TEM). The electron diffraction pattern confirmed the epitaxial relationship between each layer. The measured remanent polarization P{sub r} and coercive field E{sub c} of the PZT(20/80) thin film were 26 {mu}C/cm{sup 2} and 110 kV/cm, respectively. For PZT(53/47), P{sub r} was 10 {mu}C/cm{sup 2} and E{sub c} was 80 kV/cm.

Wang Chun; Laughlin, David E.; Kryder, Mark H. [Department of Electrical and Computer Engineering, Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2007-04-23

175

PZT on SiOx Polypyrrole on SiOx  

E-print Network

16 PZT on SiOx 90nm Polypyrrole on SiOx 120nm ZnO on SiOx 60nm 500nm SnO on SiOx 1D 2D 3D 1D on SiOx 500nm SnO on SiOx 1D 2D 3D 1D NANOSTRUCTURES 2D NANOSTRUCTURES 3D NANOSTRUCTURES Schematic NANOSTRUCTURES 2D NANOSTRUCTURES 3D NANOSTRUCTURES Schematic PZT CFO CFO@PZT on SiNx PZT on SiOx 90nm PZT on Si

Shull, Kenneth R.

176

Tides in Titan  

NASA Technical Reports Server (NTRS)

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.

Rappaport, Nicole J.

1997-01-01

177

Electrolytic deposition of PZT on carbon fibers for fabricating multifunctional composites  

NASA Astrophysics Data System (ADS)

Piezoelectric fiber composites (PFCs) have been developed in order to overcome the fragile nature of monolithic piezoelectric materials by embedding piezoceramic inclusions into a polymer matrix. The flexible nature of the polymer matrix protects the piezoelectric fiber from damage or fracture under mechanical loading and allows the composites to be easily conformed to curved surfaces for use in many applications. Although PFCs have many useful properties, they still suffer from several drawbacks, namely the required separate electrodes make it impossible to embed the composites into the host structure, and the relatively low tensile modulus of the piezoelectric inclusion means that it contributes little to structural properties. To resolve the inadequacies of current PFCs, a novel active structural fiber (ASF) was developed that can be embedded into a composite structure to perform sensing and actuation, and provide load bearing functionality. The concept and feasibility of this ASF has been validated by coating a silicon carbide (SiC) fiber with a barium titanate (BaTiO3) shell using electrophoresis deposition techniques. However, lead based ceramics react with SiC fiber during high temperature sintering and thus the use of these highly coupled piezoceramics requires alternative deposition approaches. This paper will introduce a new ASF fabricated by coating a single carbon fiber with a concentric PZT (PbZr0.52Ti0.48O3) shell using electrolytic deposition (ELD). ELD quickly and uniformly coats the fiber and, since the PZT precursor has a low crystallization temperature, the carbon fiber is not exposed to high sintering temperatures which typically degrade the in-plane material properties of the fiber and composite. Carbon fiber has been widely used in industry and studied in academia due to its excellent mechanical properties, while PZT has been extensively used for sensing or actuation because of its high piezoelectric coupling. Crystal structures of the PZT before and after annealing are characterized by means of x-ray diffraction, and a pure perovskite structure of the PZT after annealing is shown.

Lin, Y.; Shaffer, J. W.; Sodano, H. A.

2010-12-01

178

Intensive Titan exploration begins  

NASA Technical Reports Server (NTRS)

The Cassini Orbiter spacecraft first skimmed through the tenuous upper atmosphere of Titan on 26 October 2004. This moon of Saturn is unique in our solar system, with a dense nitrogen atmosphere that is cold enough in places to rain methane, the feedstock for the atmospheric chemistry that produces hydrocarbons, nitrile compounds, and Titan's orange haze. The data returned from this flyby supply new information on the magnetic field and plasma environment around Titan, expose new facets of the dynamics and chemistry of Titan's atmosphere, and provide the first glimpses of what appears to be a complex, fluid-processed, geologically young Titan surface.

Mahaffy, Paul R.

2005-01-01

179

Interior of Titan  

NASA Technical Reports Server (NTRS)

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.

Stevenson, David J.

1992-01-01

180

Genetic Adaptive Control for PZT Actuators  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

181

Impact Shock Microstructures in Apollo 14 Zircons  

NASA Astrophysics Data System (ADS)

We conducted a survey of Apollo 14 lunar zircon to search for shock features common in zircons from terrestrial impact structures. We observed a wide range of microstructural states including microstructures not previously reported in any zircon.

Crow, C. A.; Moser, D. E.; McKeegan, K. D.; Barker, I.

2014-09-01

182

Lead hafnate zirconate titanate-based perovskite materials for actuation  

Microsoft Academic Search

Antiferroelectric Pb0·98La0·02(Zr0·70Hf0·30)1?xTixO3 (0·065?x?0·10) compositions, located close to the boundary with a ferroelectric phase field, have been investigated as potential candidates for actuation through the mechanism of field induced antiferroelectric–ferroelectric phase transition. The materials were analysed by X-ray diffraction and by electromechanical measurements. The compositions with x?0·075 seemed initially located in the orthorhombic (almost tetragonal) AFEI antiferroelectric phase field. They underwent

Catherine Heremans; Harry L Tuller

1999-01-01

183

journal homepage: www.elsevier.com/locate/nanoenergy Available online at www.sciencedirect.com  

E-print Network

Chang, Liwei Linn Berkeley Sensor and Actuator Center, Department of Mechanical Engineering, University harvesting; PVDF; Piezoelectric nanofibers Abstract Nanofiber-based piezoelectric energy generators could made of PVDF (polyvinylidene fluoride) or PZT (lead zirconate titanate) and fabricated by means

Lin, Liwei

184

Pre-stressed Curved Actuators: Characterization and Modeling of their Piezoelectric Behavior  

E-print Network

Pre-stressed Curved Actuators: Characterization and Modeling of their Piezoelectric Behavior Karla actuators consist of a piezoelectric ceramic (lead zirconate titanate or PZT) sandwiched between various thermo elastic relations and ferroelectric domain theory. The model predicts displacements based

185

Shear piezoelectric coefficients of PZT, LiNbO3 and PMN-PT at cryogenic temperatures  

NASA Astrophysics Data System (ADS)

Piezoelectric transducers are used to detect stress and to generate nanometer scale displacements but their piezoelectric coefficients decrease with temperature, limiting their performance in cryogenic applications. We have developed a capacitive technique and directly measured the temperature dependence of the shear coefficient d15 for ceramic lead zirconium titanate (PZT), 41° X-cut lithium niobate (LiNbO3) and single crystal lead magnesium niobium-lead titanate (PMN-PT). In PZT, d15 decreases nearly linearly with temperature, dropping by factor of about 4 by 1.3 K. LiNbO3 has the smallest room temperature d15, but its value decreased by only 6% at the lowest temperatures. PMN-PT had the largest value of d15 at room temperature (2.9 × 10?9 m/V, about 45 times larger than for LiNbO3) but it decreased rapidly below 75 K; at 1.3 K, d15 was only about 8% of its room temperature value.

Bukhari, Syed; Islam, Md; Haziot, Ariel; Beamish, John

2014-12-01

186

Saturn Moons Explorer: Titan  

NSDL National Science Digital Library

Only now are we beginning to learn about Titan, one of Saturn's most intriguing and enigmatic moons. This particular site provides an overview of Titan, courtesy of NASA's Jet Propulsion Laboratory, located at the California Institute of Technology. After watching an introductory video segment about Titan, visitors can learn more in the "Quick Facts" section. The "Latest Images" area contains twelve of the latest images of Titan as captured by the Cassini spacecraft. Visitors should also not miss the "3D Globe" area, which contains an interactive rendering of Titan which allows visitors to visit a number of features on this moon, including an ice volcano, drainage channels, and "The Smile", the brightest spot on Titan's surface.

187

PZT-5A4/PA and PZT-5A4/PDMS piezoelectric composite bimorphs  

NASA Astrophysics Data System (ADS)

Disc type reinforced piezoelectric composite bimorphs with series connection were designed and the performance was investigated. The composite bimorphs (PZT/PA and PZT/PDMS (40/60 vol%)) were successfully fabricated by a compression molding and solution casting technique. The charge developed at an applied force of 150 N is 18150 pC (PZT/PA) and 2310 pC (PZT/PDMS), respectively. Electric force microscopy (EFM) is used to study the structural characterization and piezoelectric properties of the materials realized. A clear inverse piezoelectric effect was observed when the bimorphs were subjected to an electric field stepped up through 2, 6 and 10 V, indicating the net polarization direction of the different ferroelectric domains. The as-developed bimorphs have the basic structure of a sensor and actuator, and, since they do not use any bonding agent for bonding, they can provide a valuable alternative to the present bimorphs where bonding processes are required for their realization that can limit their application at high temperature.

Babu, I.; Hendrix, M. M. R. M.; de With, G.

2014-02-01

188

Titanic: Discovery Channel  

NSDL National Science Digital Library

RMS Titanic raised a 23- by 14-foot section of the Titanic's outer hull this week, and the Discovery Channel, who helped sponsor the expedition, will be webcasting live from the interior of the Titanic via robot cameras August 16 at 8:00 and 10:00 p.m. (Eastern Time). In addition to their live webcase, the Discovery Channel site (discussed in the December 5, 1997 issue of the Scout Report) features virtual reality tours of sections of the Titanic before and after its crash, quicktime videos of the expeditions, a computer animated simulation of the crash, and more.

189

Etching fission tracks in zircons  

USGS Publications Warehouse

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.

Naeser, C.W.

1969-01-01

190

Neutron Scattering Study of Single Crystal PZT  

NASA Astrophysics Data System (ADS)

Single crystal specimens of the technologically important ferroelectric material Pb(Zr1-xTix)O3, or PZT, have only recently been grown for the first time at Simon Fraser University. We have characterized the transition temperatures, thermal expansion, and crystal structure of a PZT single crystal between 10 K and 670 K using neutron scattering methods. This crystal, which has a composition (x˜0.46) that lies close to the morphotropic phase boundary (MPB), exhibits a surprisingly large thermal expansion (˜ 10-3 1/K) that changes sign near 545 K, and a rhombohedral crystal structure at 30 K. In addition we observe an enormous relief of extinction beginning around 650 K, which was observed through the temperature dependence of the (200) Bragg peak. Neutron inelastic measurements are planned as are measurements under an applied electric field. This work was supported by the U. S. Office of Naval Research (Grant No. N00014-1-06-0166). All neutron measurements were performed at the NIST Center for Neutron Research.

Phelan, Daniel; Gehring, Peter; Ye, Zuo-Guang; Long, Xifa

2010-03-01

191

ORNL debuts Titan supercomputer  

E-print Network

SCIENCE ORNL debuts Titan supercomputer ORNL has completed the installation of Titan, a supercomputer capable of churning through more than 20,000 trillion calculations each second--or 20 petaflops Jaguar predecessor while using only marginally more electricity. "One challenge in supercomputers today

Pennycook, Steve

192

Clash of the Titans  

ERIC Educational Resources Information Center

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,"…

Subramaniam, Karthigeyan

2010-01-01

193

Titan Airship Explorer  

Microsoft Academic Search

Saturn's moon Titan is considered to be one of the prime locations for understanding the origins of life due to its rich environment of organic chemicals. A unique combination of dense atmosphere (more than four times that of the Earth), low gravity (one-sixth of that on the Earth) and small temperature variations makes Titan well-suited for studies with buoyant robotic

Jeffery L. Hall; Viktor V. Kerzhanovich; J. A. Jones; J. A. Cutts; A. A. Yavrouian; A. Colozza; R. D. Lorenz

2002-01-01

194

Titan buoyant station  

NASA Technical Reports Server (NTRS)

The proposed mission concept evolves about one or more buoyant stations (balloons and/or airship) operating at varying altitudes in Titan's atmosphere. An orbiter of Titan provides communications link support and accomplishes remote sensing science experiments. The paper describes science objectives and payloads, the reference mission concept and various aspects of mission design analysis.

Friedlander, A. L.

1984-01-01

195

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

SciTech Connect

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.

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

2010-07-01

196

Change in the Dielectric Properties of Normal and Relaxor Ferroelectric Ceramic Composites in BT-PZT and PMN-PZT Systems by an Uniaxial Compressive Stress  

Microsoft Academic Search

Effects of an uniaxial compressive pre-stress on the dielectric properties of normal and relaxor ferroelectric ceramic composites in BT-PZT and PMN-PZT systems are investigated. The dielectric properties are observed under the compressive pre-stress levels up to 15 and 5 MPa for BT-PZT and PMN-PZT, respectively, using a uniaxial compressometer. Both the dielectric constant and the dielectric loss tangent of the

Rattikorn Yimnirun

2006-01-01

197

Fabrication of Flexible Piezoelectric PZT/Fabric Composite  

PubMed Central

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

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

2013-01-01

198

The TITAN reversed-field-pinch fusion reactor study  

SciTech Connect

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.

Not Available

1990-01-01

199

Effects of laser radiation on photoconductivity in PZT thin films  

Microsoft Academic Search

Excitation photocurrent spectroscopy (EPS) was used to record photoconductivity from 200 to 600 nm for a Pb(Zr0.53Ti0.47)O3 (PZT) thin film. Four spectral bands at 262, 338, and 428\\/472 nm were observed and assigned tentatively to originate from Pb, O(vacancy center) and Fe (impurity and\\/or ion-doped) centers, respectively. When the band at 262 nm in the PZT film was excited using

Li Li; Chhiu-Tsu Lin; Martin S. Leung; Russell A. Lipeles

1995-01-01

200

Titan's Lower Atmosphere  

NASA Astrophysics Data System (ADS)

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.

Griffith, Caitlin Ann

2007-09-01

201

Impact craters on Titan  

Microsoft Academic Search

Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan’s surface imaged by Cassini’s high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions

Charles A. Wood; Ralph Lorenz; Randy Kirk; Rosaly Lopes; Karl Mitchell; Ellen Stofan

2010-01-01

202

Titan: some new results.  

PubMed

New analyses of Voyager spectra of Titan have led to improvements in the determination of abundances of minor constituents as a function of latitude and altitude. Ground-based microwave observations have extended the Voyager results for HCN, and have demonstrated that CO is mysteriously deficient in the stratosphere. The origin of the CH4, CO, and N2 in Titan's atmosphere is still unresolved. Both primordial and evolutionary sources are compatible with the available evidence. PMID:11537362

Owen, T; Gautier, D

1989-01-01

203

Misted Deposition of [3D] Trenches for Drams and Frams III. PZT Thin Films and PZT Nanotubes  

Microsoft Academic Search

Pb(Zr,Ti)O3 (PZT) thin films and nanotube were prepared on SiO2\\/Si substrates by liquid source misted chemical deposition (LSMCD) using Samco MD-6060 apparatus. We report the deposition and characterization of transparent ferroelectric thin films and nanotubes. PZT thin films deposited at ambient conditions and annealing at 700degC exhibit good ferroelectric properties with remanent polarisation of ca. 15 muC\\/cm2. The step coverage

M. Miyake; J. F. Scott; X.-J. Lou; F. D. Morrison; S. Motoyama; T. Tatsuta; O. Tsuji

2007-01-01

204

Spectral Characteristics of Titan's Surface  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

205

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

Microsoft Academic Search

Zircons found in mantle-sourced kimberlite provide probes into the isotopic chemistry of the asthenosphere and subcontinental lithospheric mantle. However, little is known about the conditions of formation of these zircons. A suite of 88 zircons found in kimberlites from Africa, Siberia, Brazil, and the United States have been analyzed for their Ti concentration and selected zircons were analyzed for their

F. Zeb Page; Bin Fu; Noriko T. Kita; John Fournelle; Michael J. Spicuzza; Daniel J. Schulze; Fanus Viljoen; Miguel A. S. Basei; John W. Valley

2007-01-01

206

The environment of Titan, 1975  

NASA Technical Reports Server (NTRS)

Information regarding the physical characteristics of Titan and atmospheric models necessary to support design and mission planning of spacecraft that are to orbit Titan, enter its atmosphere or land on its surface is given.

1976-01-01

207

Multiferroic properties of Pb(Zr,Ti)O3\\/CoFe2O4 composite thin films  

Microsoft Academic Search

In the present work we report multiferroic behavior in lead zirconate titanate (PZT)-cobalt iron oxide (CFO) composite thin films. It is found that upon annealing, the multilayered structures are intermixed at least partially, and CFO is phase separated into PZT matrix to form a composite film. The phase separation behavior has been characterized by x-ray photoelectron spectroscopy depth profiling of

N. Ortega; P. Bhattacharya; R. S. Katiyar; P. Dutta; A. Manivannan; M. S. Seehra; I. Takeuchi; S. B. Majumder

2006-01-01

208

T d M ll A Sit D i D di T j Si i R i Computer Science and Engineering UCSD  

E-print Network

Actuating Circuit 1800 360 @5V Sensing Circuit 200 40 @5V Lead-Zirconate-Titanate piezoelectric transducers iezoelectric ransducers piezoelectric transducers (PZT): one PZT serves as an actuator, creating vibrations, d RAM, up to 32GB flash · High-Voltage supply for Actuating and Sensing to increase the signal strength

Simunic, Tajana

209

2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 www.advmat.de  

E-print Network

building blocks of future electronic, electromechanical, optoelectronic, sensing and actuation nanosystemsN) or ferroelectrics (e.g., PZT, BaTiO3), are technologically relevant and have received increased attention because such as lead-zirconate-titanate (PZT)[15] and flex- ible piezoelectric polymers such as poly

Espinosa, Horacio D.

210

Titan's Nitrogen Budget  

NASA Astrophysics Data System (ADS)

The destruction of nitrogen through photolysis and electron impact processes in Titan's upper atmosphere and through cosmic ray ionization in Titan's stratosphere results in the formation of nitrile molecules, which are transported into the stratosphere, and nitrogen-based ions, which populate Titan's upper and lower ionosphere. These compounds contribute to the possible formation of ion clusters and to the eventual incorporation of nitrogen into Titan haze, which has been investigated by laboratory studies and confirmed by observations from the Huygens Aerosol Collector Pyrolyser (ACP) instrument [1]. However, the mechanisms by which these processes occur are still largely unknown. One of the barriers to our understanding is the fact that a significant portion of Titan's nitrogen budget goes into compounds for which there has been little study at low temperatures, compounds like methanimine (CH2NH) and the carbene imine ion (C3NH+). These imines, which exhibit the N-H functional group, may play a significant role in the nitrogen incorporation into haze as shown by the detection of the N-H functional group in the sample analyzed by the ACP instrument [1] and by laboratory studies. This poster will detail the current state of knowledge of Titan's nitrogen budget, as elucidated by the recent observations of the Cassini-Huygens mission, and this study will explore the potential role of these understudied compounds in the production of haze and possible formation of amino acids on or near the surface, the study of which having potential implications on future in-situ investigations of Titan. This research is supported by a grant from the NASA Outer Planets Program. [1] Israel, G., et al., Nature, 438, 796-799, 2005.

Wilson, Eric H.

2006-09-01

211

Oases on Titan?  

NASA Astrophysics Data System (ADS)

Titan has clouds, rain and lakes, like Earth, but composed of methane rather than water. Unlike Earth, most of the condensible, the equivalent of 5m of methane globally averaged, lies in the atmosphere. That detected on the surface ( 2m) appears black in Cassini Radar images. These lakes reside only poleward of the 50 latitude circles, where their presence is expected, because Titan's circulation efficiently transports methane to the poles, thereby desiccating the tropics. Here we present an investigation of Titan's tropical surface, using VIMS data recorded within 20S and 20N latitude (Nature, 486, 327, 2012). With a radiative transfer calculation that reproduces the in situ measurements by the Huygens Probe, we can derive the surface albedos to within 2% at 5 of the 7 window wavelength regions that probe Titan's surface. Our analysis detects the presence of a 2,400 km^2 region where the surface is uniformly black at the 7 near-IR windows. These measurements indicate the presence of a ?1m deep tropical lake, which is long lasting, having existed since 2004. Also indicated is the existence of several shallow ponds with ankle level depths. Because liquid methane is unstable on Titan's tropical surface, this unexpected detection indicates a recent supply of methane from the subsurface. Our study poses the question of whether subsurface reservoirs supply Titan's atmospheric methane. Such a source would explain the methane and the abounding organic material in Titan's atmosphere, which is produced by the irreversible photolysis of methane. Unless resupplied, the current atmospheric methane inventory will be exhausted in 20 million years.

Griffith, Caitlin Ann; Lora, J. M.; Turner, J. D.; Penteado, P. F.; Brown, R. H.; Tomasko, M. G.; Doose, L.; See, C.

2012-10-01

212

Titan's impact history  

NASA Astrophysics Data System (ADS)

Impacts play a major role in the growth and evolution of planets, satellites, and other nameless things. Titan is no exception. This talk will address a subset of the following topics: (i) The modern impact rate is constrained by the population of Centaurs and the impact rate at Jupiter. (ii) Titan's thick atmosphere and volatile surface cause it to respond to major impacts in an Earth-like manner. The impact that made Menrva - the 440 km diameter impact basin sited near the current apex of Titan's motion - was big enough to raise the average global surface temperature above 273 K, which suggests that water rain was possible. This would have been followed by methane drizzles lasting for thousands of years. More modest impacts will generate crater lakes and will saturate the atmosphere with methane, the latter leading to hundreds of years of intermittent drizzle. (iii) Impact ejecta from Menrva will strike Hyperion and should saturate the latter with sesquinary craters. (iv) In any modern story of how Titan got its atmosphere, solar nebular condensates (comets) deliver the volatiles. A consequence of a cometogenic atmosphere is that the atmosphere is heavily processed by strong shocks. The high temperatures produce a wide range of chemical species that would not otherwise be abundant. Some of these will survive to mix into the atmosphere (e.g., CO) or freeze out to fall to the surface (e.g. CO2). (v) That Titan even has an atmosphere, when Callisto and Ganymede do not, is an excellent question. The leading explanation is that Titan alone was made from ammonia - and methane - rich stuff. But the competition between impact delivery and impact expulsion of volatiles can strongly favor Titan over Callisto. Stable isotopes as well as total volatile inventories provide constraints.

Zahnle, Kevin

2010-04-01

213

PZT Actuated Seesaw SPDT RF MEMS Switch  

NASA Astrophysics Data System (ADS)

A low actuation voltage and no contact stiction are important factors in applying micro-electro-mechanical-system (MEMS) RF switches to mobile communication devices. Conventional electrostatic RF MEMS switches require several tens of voltages for actuation. In this paper we propose a piezoelectric actuated seesaw (PAS) RF MEMS switch which adopts Pb(Zr, Ti)O3 (PZT) actuators and seesaw cantilevers to meet the above requirements. The fundamental structures of PAS RF MEMS switches were designed, optimized, and fabricated. Through the developed process of PAS single pole double through (SPDT), RF MEMS switches were successfully fabricated on a 4'' wafer and they showed good electrical properties. The driving voltage was less than 5 volts and the insertion loss was -0.5dB and the isolation was -35dB at 5GHz. The maximum switching speed was about 5kHz. Thus these RF MEMS switches can be applicable to mobile communication devices or wireless multi-media devices at a frequency lower than 6GHz.

Lee, Dae-Sung; Jung, Suk-Won; Cho, Nam-Kyu; Kim, Won-Hyo; Seong, Woo-Kyeong; Park, Hyo-Derk

2006-04-01

214

Li isotopes in archean zircons  

NASA Astrophysics Data System (ADS)

Li is a fluid mobile, moderately incompatible element with a large mass difference between its two stable isotopes. Different processes can fractionate 7Li/6Li (fluid-rock interaction, metamorphic reactions, and Li diffusion), leading to variation by over 50‰ of ?7Li for common crustal material. These large variations make ?7Li a potential tracer of continental weathering and of the fluids affecting magma sources. Here, we report ?7Li and trace elements in Archean igneous zircons from TTG and sanukitoid granitoids from the Superior Province (Canada) in order to characterize Li in Archean zircons from well-described samples. These data are compared to detrital zircons from the Jack Hills (Western Australia) for which parent rock-type is uncertain. This study aims to better understand Li substitution in zircon and to evaluate the utility of ?7Li and [Li] for Archean petrogenesis. Zircons (n=71) were analyzed for ?7Li and trace elements (Li, P, Ca, Ti, V, Fe, Y, REE, U, Th) using an IMS-1280 ion microprobe. Most of the zircons display typical igneous REE patterns and zoning by CL. [Li] averages 13.1 ± 9 for TTG, 25.7 ± 19 for Sanukitoid and 31.0 ± 14 ppm for Jack Hills zircons, which are distinct from mantle-related zircons (<0.1 ppm). Values of ?7Li average 1.0 ± 4.5‰ for TTGs, 6.3 ± 4.4‰ for sanukitoids and -2.6 ± 8.8‰ for Jack Hills samples. Trace elements were analyzed from single spots in order to evaluate coupled substitutions. Atomic ratios (3Li+Y+REE)/P average 2.6, showing that Li and trivalent atoms are not charge-balanced by P, and suggesting that Li does not replace Zr, according to the xenotime substitution. However, (Y+REE)/(Li+P) atomic ratios average 1.0 ± 0.6, supporting the hypothesis that Li is interstitial and partly compensates trivalent cations. Several observations in this study suggest that [Li] is primary in the studied zircons: i) if Li is interstitial, charge-balance and slow diffusion of REE would control Li mobility, ii) core-rim or oscillatory zoning is observed for [Li] in many high T zircons, iii) CL zoning and low Ca+Fe, U+Th and U/Th imply little radiation damage. Values of ?7Li become erratic at [Li] < ~5 ppm and low values are not interpreted. We suggest that small amounts of non-ionic substitution could be significant for small [Li], whereas interstitial substitution dominates at > ~5 ppm. Li content and isotopic compositions of TTG zircons suggest genesis from mantle-like material, as suggested by ?18O(Zrc) (5.5 ± 0.4‰, King et al., 1998). Sanukitoids are commonly thought to be derived from the melting of peridotite metasomatized by seawater-like slab-dehydration fluids, (supported by the high ?7Li(Zrc)), followed by extensive fractional crystallization, explaining the high sanukitoid [Li]. [Li] and ?7Li thus reflect petrogenetic processes. The Jack Hills detrital zircons are consistent with crustal sources including TTG, sanukitoid and sediment-contaminated granitoid magmas.

Bouvier, A.; Ushikubo, T.; Kita, N.; Cavosie, A. J.; Kozdon, R.; Valley, J. W.

2009-12-01

215

The Titan Graphics Supercomputer Architecture  

Microsoft Academic Search

The design criteria for the Titan are outlined, and the hardware, architecture, and implementation developed to meet them are examined. The key architectural elements in Titan are described, and the reasoning behind their selection is presented. Titan's processor subsystem is explored, focusing on how it reduces the cost and complexity of graphics-specific hardware. The design constraints and implementation of the

Tom Diede; Carl F. Hagenmaier; Glen S. Miranker; Jonathan J. Rubinstein; William S. Worley Jr.

1988-01-01

216

Barium titanate nanocomposite capacitor FY09 year end report.  

SciTech Connect

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.

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

217

The Titan Aerosol Simulants Produced at Low Temperature in the Titan Haze Simulation Experiment at NASA Ames: A Closer Analog of Titan's Aerosols?  

NASA Astrophysics Data System (ADS)

The Titan Haze Simulation experiment simulates the first steps of Titan’s atmospheric chemistry at low temperature and produces aerosols that are simpler than other lab experiments’ and appear to be more representative of Titan’s aerosols.

Sciamma-O'Brien, E. M.; Upton, K. T.; Beauchamp, J. L.; Salama, F.

2014-02-01

218

Titan's methane cycle  

NASA Astrophysics Data System (ADS)

Methane is key to sustaining Titan's thick nitrogen atmosphere. However, methane is destroyed and converted to heavier hydrocarbons irreversibly on a relatively short timescale of approximately 10-100 million years. Without the warming provided by CH 4-generated hydrocarbon hazes in the stratosphere and the pressure induced opacity in the infrared, particularly by CH 4-N 2 and H 2-N 2 collisions in the troposphere, the atmosphere could be gradually reduced to as low as tens of millibar pressure. An understanding of the source-sink cycle of methane is thus crucial to the evolutionary history of Titan and its atmosphere. In this paper we propose that a complex photochemical-meteorological-hydrogeochemical cycle of methane operates on Titan. We further suggest that although photochemistry leads to the loss of methane from the atmosphere, conversion to a global ocean of ethane is unlikely. The behavior of methane in the troposphere and the surface, as measured by the Cassini-Huygens gas chromatograph mass spectrometer, together with evidence of cryovolcanism reported by the Cassini visual and infrared mapping spectrometer, represents a "methalogical" cycle on Titan, somewhat akin to the hydrological cycle on Earth. In the absence of net loss to the interior, it would represent a closed cycle. However, a source is still needed to replenish the methane lost to photolysis. A hydrogeochemical source deep in the interior of Titan holds promise. It is well known that in serpentinization, hydration of ultramafic silicates in terrestrial oceans produces H 2(aq), whose reaction with carbon grains or carbon dioxide in the crustal pores produces methane gas. Appropriate geological, thermal, and pressure conditions could have existed in and below Titan's purported water-ammonia ocean for "low-temperature" serpentinization to occur in Titan's accretionary heating phase. On the other hand, impacts could trigger the process at high temperatures. In either instance, storage of methane as a stable clathrate-hydrate in Titan's interior for later release to the atmosphere is quite plausible. There is also some likelihood that the production of methane on Titan by serpentinization is a gradual and continuous on-going process.

Atreya, Sushil K.; Adams, Elena Y.; Niemann, Hasso B.; Demick-Montelara, Jaime E.; Owen, Tobias C.; Fulchignoni, Marcello; Ferri, Francesca; Wilson, Eric H.

2006-10-01

219

Determination of uranium in zircon  

USGS Publications Warehouse

A routine fluorimetric procedure is described for the determination of trace amounts of uranium in zircon. It employs the direct extraction of uranyl nitrate with ethyl acetate using phosphate as a retainer for zirconium. Submicrogram amounts or uranium are separated in the presence of 100,000 times the amount of zirconium. The modified procedure has been worked out using synthetic mixtures of known composition and zircon. Results of analyses have an accuracy of 97-98% of the contained uranium and a standard deviation of less than 2.5%. ?? 1959.

Cuttitta, F.; Daniels, G.J.

1959-01-01

220

Titan Orbiter Aerorover Mission  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

221

Early History of Titan  

NASA Astrophysics Data System (ADS)

We revisit models for the early history of Titan. Our models start a few My after the production of calcium- aluminum inclusions (CAIs), consistent with the dates required by our thermophysical-dynamical modeling of Saturn's medium-sized satellites. Depending on the time of formation with respect to CAIs, the accretion time scale, and the available accretional energy, models of Titan's interior after accretion are partially to fully differentiated. At one extreme of the models, Titan accretes incorporating a minimal amount of heat. This results in a relatively cold core that, over the long term, heats up and overturns, consistent with previous models of Titan. At the other extreme, accretional heat and heat fom the decay of short-lived radiogenic isotopes results in quick and complete differentiation. In this model there is no core overturn, and conditions soon develop for silicate serpentinization, and hydrothermal activity starts. We identify the periods during which conditions are suitable for hydrothermal geochemistry leading to the production of molecular nitrogen from ammonia decomposition and methane from the Fischer-Tropsch reaction. Key questions include the availability of suitable metal catalysts and/or clay minerals, storage of the reactants and products in the interior of Titan, and mechanisms by which they are released to the atmosphere. Acknowledgements: This work was carried out at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA.

Castillo-Rogez, J. C.; Matson, D. L.; Johnson, T. V.; Atreya, S.; Lunine, J. I.

2007-05-01

222

Work of PZT ceramics sounder for sound source artificial larynx  

NASA Astrophysics Data System (ADS)

We aim to develop the easy-to-use artificial larynx with high tone quality. We focus on using a PZT ceramics sounder as its sound source, because it is small size, low power consumption, and harmless to humans. But conventional PZT ceramics sounder have the problem that it cannot generate an enough sound in the low frequency range, thus they cannot be used for artificial larynx. Then, we aim to develop the PZT ceramics sounder which can generate enough volume in the low frequency range. If we can lower the resonance frequency of the sounder, it can generate low pitch sound easily. Therefore I created the new diaphragm with low resonance frequency. In addition, we could obtain the high amplitude by changing method of driving. This time, we report on the characteristic comparison of this new PZT ceramics sounder and conventional one. Furthermore, for this new one, we analyzed the best alignment of PZT ceramics and the shape of the diaphragm to obtain low resonance frequency and big amplitude. In fact we analyzed the optimization of the structure. The analysis is done by computer simulation of ANSYS and Laser Doppler Vibrometer. In the future, we will add intonation to the generated sound by input wave form which is developed concurrently, and implant the sounder inside of the body by the method of fixing metal to biomolecule which is done too. And so high tone quality and convenient artificial larynx will be completed.

Sugio, Yuuichi; Kanetake, Ryota; Tanaka, Akimitsu; Ooe, Katsutoshi

2007-04-01

223

The tides of Titan.  

PubMed

We have detected in Cassini spacecraft data the signature of the periodic tidal stresses within Titan, driven by the eccentricity (e = 0.028) of its 16-day orbit around Saturn. Precise measurements of the acceleration of Cassini during six close flybys between 2006 and 2011 have revealed that Titan responds to the variable tidal field exerted by Saturn with periodic changes of its quadrupole gravity, at about 4% of the static value. Two independent determinations of the corresponding degree-2 Love number yield k(2) = 0.589 ± 0.150 and k(2) = 0.637 ± 0.224 (2?). Such a large response to the tidal field requires that Titan's interior be deformable over time scales of the orbital period, in a way that is consistent with a global ocean at depth. PMID:22745254

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

2012-07-27

224

Impact craters on Titan  

NASA Astrophysics Data System (ADS)

Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; Cassini Radar Team

2010-03-01

225

Impact craters on Titan  

USGS Publications Warehouse

Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles. ?? 2009 Elsevier Inc.

Wood, C.A.; Lorenz, R.; Kirk, R.; Lopes, R.; Mitchell, K.; Stofan, E.

2010-01-01

226

Impact craters on Titan  

USGS Publications Warehouse

Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; Cassini RADAR Team

2010-01-01

227

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

228

Aboard the Titanic  

NSDL National Science Digital Library

You will be exploring the R.M.S Titanic. This includes an individual passenger, the class system on board, the collision and warnings leading up to it, and the construction of the ship. Introduction: You are going to be a passenger on board the RMS Titanic. You boarded the ship and set sail expecting the experience of a lifetime upon the Ship of Dreams, but what will happen next? In this project we will be exploring how the ship was structured, what activities were ...

Maahs, Mrs.

2010-04-20

229

Titan's Winter Polar Vortex  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

230

High quality PZT thick films using silicon mold technique for MEMS applications  

Microsoft Academic Search

The present paper proposes a simple fabrication technique of high quality PZT thick films that call for silicon mold technique. The fabrication process adopts the silicon with back window obtained from silicon anisotropic etching as the silicon mold, and the improved PZT sol is dispensed in the silicon mold. The PZT films obtained using single spin coating with the thickness

Hong-Jin Zhao; Tian-Ling Ren; Jian-She Liu; Li-Tian Liu; Zhi-Jian Li

2003-01-01

231

Ti-in-zircon thermometry: applications and limitations  

Microsoft Academic Search

The titanium concentrations of 484 zircons with U-Pb ages of ˜1 Ma to 4.4 Ga were measured by ion microprobe. Samples come from 45 different igneous rocks (365 zircons), as well as zircon megacrysts (84) from kimberlite, Early Archean detrital zircons (32), and zircon reference materials (3). Samples were chosen to represent a large range of igneous rock compositions. Most

Bin Fu; F. Zeb Page; Aaron J. Cavosie; John Fournelle; Noriko T. Kita; Jade Star Lackey; Simon A. Wilde; John W. Valley

2008-01-01

232

Semiconducting barium titanate  

Microsoft Academic Search

Barium titanate, which is well known as a basic ferroelectric material, is also of interest when doped because of the interaction between semiconductivity and ferroelectricity. The resistance of blocking layers at surfaces and grain-boundaries is governed mainly by the ferroelectric properties, so that a resistance jump of four decades is observed on heating above the Curie temperature. A survey of

W. Heywang

1971-01-01

233

Future Titan Mission Studies  

NASA Astrophysics Data System (ADS)

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.

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

234

The lakes of Titan  

USGS Publications Warehouse

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.

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

235

Intelligence Analysis Using Titan  

Microsoft Academic Search

The open source Titan Informatics Toolkit Project, which extends the Visualization Toolkit (VTK) to include information visualization capabilities, is being developed by Sandia National Laboratories in collaboration with Kitware. The VAST Contest provided us with an opportunity to explore various ideas for constructing an analysis tool, while allowing us to exercise our architecture in the solution of a complex problem.

Patricia Crossno; Brian N. Wylie; Andrew Wilson; John Greenfield; Eric T. Stanton; Timothy M. Shead; Lisa Ice; Kenneth Moreland; Jeffrey Baumes; Berk Geveci

2007-01-01

236

Piezoceramic Materials as Enablers of New Technology Devices  

Microsoft Academic Search

Micro-tubes made out of improved lead zirconate titanate (PZT) material are used to develop a new optical switch. These PZT micro-tubes are being manufactured by an electrophoretic deposition process (EPD). EPD overcomes some of the processing problems of other conventional processing techniques. PZT tubes with less than 1mm outer diameter were fabricated successfully with EPD. The analysis of various design

E. Haemmerle; M. Leung; W. Gao; J. Yoo

2006-01-01

237

Effect of Driving Field and Temperature on the Response Behavior of Ferroelectric Actuator and Sensor Materials  

Microsoft Academic Search

Three commonly used ferroelectric actuator and sensor materials, namely polyvinylidene fluoride copolymers, lead zirconate titanate piezoceramics (PZT), and lead magnesium niobate-lead titanate relaxors (PMN-PT) at low PT content, are characterized with respect to temperature and driving field amplitude. It is shown that changes in the response and loss with the driving field amplitude are mainly caused by irreversible process and

Q. M Zhang; H. Wang; J. Zhao

1995-01-01

238

Resonance-Shift Gas Pressure Sensors Based on Bulk PZT  

Microsoft Academic Search

A resonance-shift pressure sensor was designed and fabricated using MEMS technology in order to detect gas flow pressure. The pressure sensor is made of silicon and Pyrex glass, and is actuated by a piece of bulk PZT with the thickness of 191 µm. An actuation element for silicon thin film and gas flow pressure change the frequency of fundamental mode

Yi-Chu Hsu; Ming-Can Wu; Ling-Sheng Jang

239

Ti-in-Zircon Thermometer: Preliminary Results  

Microsoft Academic Search

The titanium in zircon thermometer has been applied to 167 zircons from diverse rock types. These rocks include metamorphosed anorthosite and gabbro (1.15 Ga, intrusion age), and unmetamorphosed granitic pegmatite (0.9 Ga) from the Adirondack Highlands; metaluminous and peraluminous granites (114-90 Ma) of the Sierra Nevada Batholith; megacrysts from kimberlite pipes in southern Africa, Brazil, and Siberia; and detrital zircons

B. Fu; A. J. Cavosie; C. C. Clechenko; J. Fournelle; N. T. Kita; J. Lackey; F. Page; S. A. Wilde; J. W. Valley

2005-01-01

240

Properties of Semiconductive Barium Titanates  

Microsoft Academic Search

The resistivity of barium titanate which is usually of the order of 109˜1012 ohm-cm, may be remarkably reduced with suitable control in valency. The valency-controlled barium titanate, whose resistivity is of the order of 10˜104 ohm-cm at room temperature, shows anomalous positive character in the temperature dependency of the resistivity. For example, the resistivity of barium titanate containing 0.1 mol.

Osamu Saburi

1959-01-01

241

Organic chemistry on Titan  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

242

RADAR Reveals Titan Topography  

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

243

Ethane ocean on Titan  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

244

Quantitative comparison between the degree of domain orientation and nonlinear properties of a PZT ceramic during electrical and mechanical loading  

SciTech Connect

The macroscopic electromechanical coupling properties of ferroelectric polycrystals are composed of linear and nonlinear contributions. The nonlinear contribution is typically associated with the extrinsic effects related to the creation and motion of domain walls. To quantitatively compare the macroscopic nonlinear properties of a lead zirconate titanate ceramic and the degree of domain orientation, in-situ neutron and high-energy x-ray diffraction experiments are performed and they provide the domain orientation density as a function of the external electric field and mechanical compression. Furthermore, the macroscopic strain under the application of external electrical and mechanical loads is measured and the nonlinear strain is calculated by means of the linear intrinsic piezoelectric effect and the linear intrinsic elasticity. The domain orientation density and the nonlinear strain show the same dependence on the external load. The scaling factor that relates to the two values is constant and is the same for both electrical and mechanical loadings.

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L. (Florida); (Darmstadt)

2011-10-26

245

Crystalline titanate catalyst supports  

DOEpatents

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.

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

1993-01-05

246

Crystalline titanate catalyst supports  

DOEpatents

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.

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

1993-01-01

247

The albedo of Titan  

NASA Astrophysics Data System (ADS)

Photometric observations of Titan since 1972 show a cyclical variation of ?10%. A minimum value of brightness and albedo apparently occurred in 1984. Spectrophotometric observations, made annually since 1980 at 8 Å resolution, 3295 - 8880 Å, were used to derive the value p* = 0.156±0.010 for integrated geometric albedo in 1984. Variations of the equivalent widths of spectral features were not seen.

Lockwood, G. W.; Lutz, B. L.; Thompson, D. T.; Bus, E. S.

1986-04-01

248

Titan's methane cycle  

Microsoft Academic Search

Methane is key to sustaining Titan's thick nitrogen atmosphere. However, methane is destroyed and converted to heavier hydrocarbons irreversibly on a relatively short timescale of approximately 10 100 million years. Without the warming provided by CH4-generated hydrocarbon hazes in the stratosphere and the pressure induced opacity in the infrared, particularly by CH4 N2 and H2 N2 collisions in the troposphere,

Sushil K. Atreya; Elena Y. Adams; Hasso B. Niemann; Jaime E. Demick-Montelara; Tobias C. Owen; Marcello Fulchignoni; Francesca Ferri; Eric H. Wilson

2006-01-01

249

Titan's methane cycle  

Microsoft Academic Search

Methane is key to sustaining Titan's thick nitrogen atmosphere. However, methane is destroyed and converted to heavier hydrocarbons irreversibly on a relatively short timescale of approximately 10–100 million years. Without the warming provided by CH4-generated hydrocarbon hazes in the stratosphere and the pressure induced opacity in the infrared, particularly by CH4–N2 and H2–N2 collisions in the troposphere, the atmosphere could

Sushil K. Atreya; Elena Y. Adams; Hasso B. Niemann; Jaime E. Demick-Montelara; Tobias C. Owen; Marcello Fulchignoni; Francesca Ferri; Eric H. Wilson

2006-01-01

250

Landscape Evolution of Titan  

NASA Technical Reports Server (NTRS)

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.

Moore, Jeffrey

2012-01-01

251

Laboratory Simulations Of Titan’s Atmospheric Chemistry With The NASA Ames Titan Haze Simulation Experiment  

NASA Astrophysics Data System (ADS)

Solar UV radiation and electron bombardment from Saturn’s magnetosphere dissociate nitrogen and methane in Titan’s atmosphere, leading to the production of heavier molecules and solid organic aerosols that contribute to the haze layers giving Titan its characteristic orange color. The detection of benzene and toluene, critical precursors of polycyclic aromatic hydrocarbon (PAH), in Titan’s ionosphere, by the Cassini INMS suggests that PAHs might play a role in the production of Titan’s aerosols. The Titan Haze Simulation (THS) experiment has been developed at NASA Ames’ Cosmic Simulation facility (COSmIC) to study the chemical pathways that link the simple molecules resulting from the first steps of the N2-CH4 chemistry (C2H2, C2H4, HCN..) to benzene, and to PAHs and nitrogen-containing PAHs (PANHs) as precursors to the production of solid aerosols. In the THS experiment, Titan’s atmospheric chemistry is simulated by plasma in the stream of a supersonic jet expansion. With this unique design, the gas mixture is cooled to Titan-like temperature ( 150K) before inducing the chemistry by plasma discharge. Different gas mixtures containing the first products of Titan’s N2-CH4 chemistry, but also much heavier molecules like PAHs or PANHs can be injected to study specific chemical reactions. The products of the chemistry are detected and studied using Cavity Ring Down Spectroscopy and Time-Of-Flight Mass Spectrometry. Thin tholin (Titan aerosol analogs) deposits are also produced in the THS experiment and can be analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Scanning Electron Microscopy (SEM). We present the results of mass spectrometry studies using different gas mixtures, and discuss their relevance for the study of specific pathways in Titan’s atmospheric chemistry. Acknowledgements: This research is supported by NASA PATM. E.S.O., C.S.C. and C.L.R acknowledge the support of the NASA Postdoctoral Program. The authors acknowledge the collaboration of H. Imanaka, C. McKay and S. Lebonnois.

Sciamma-O'Brien, Ella; Contreras, C. S.; Ricketts, C. L.; Salama, F.

2012-05-01

252

Study for piezoelectric characterization of PZT actuators deposited by RF magnetron sputtering for MEMS  

NASA Astrophysics Data System (ADS)

Pb(Zr,Ti)O3 piezoelectric material(PZT) has been utilized for a microactuators or microsensors. Because PZT piezoelectric materials have higher power or larger displacement than the other piezoelectric materials such as BaTiO3. The PZT thin films were deposited onto a heated Invar alloy by using a high temperature RF magnetron sputtering. The chemical composition and the crystalline structure for deposited PZT were measured by ESCA and XRD, respectively. The chemical composition of PZT deposited stoichiometrically was almost same as the commercial based bulk PZT composition. Crystal planes (110) and (111) of PZT Perovskite structure were observed in XRD analysis. Employing over 600 degree heating, almost no pinhole on the surface was observed by SEM. Thin film actuator with 500 nm thickness has been also characterized by measuring the piezoelectric property using Laser Doppler Vibrograph. It was confirmed that the piezoelectric property has a linear relationship with the grain size, which also increased with the substrate temperature. Therefore, it is possible to control piezoelectric properties by the sizes of PZT grain, which is grown by heating substrate. The piezoelectric property of deposited PZT thin films showed a good agreement with a quoted value of bulk PZT, when the substrates were heated up at 600 degree.

Tsuchiya, Kazuyoshi; Kitagawa, Toshiaki; Nakamachi, Eiji

2002-11-01

253

New experimental constraints for Hadean zircon source melts from Ce and Eu anomalies in zircon  

NASA Astrophysics Data System (ADS)

A common feature of zircon rare earth element profiles is that they often have enriched chondrite normalized Ce abundances relative to bracketing rare earth elements (REEs) La and Pr. The magnitude of a zircon Ce anomaly is generally attributed to an increase in Ce4+/Ce3+ of the crystallizing medium (Ce4+ is more compatible than Ce3+ in zircon), which is associated with more oxidizing environments. Zircons may also have depleted chondrite normalized Eu abundances relative to Sm and Gd. A negative Eu anomaly may be indicative of more reducing conditions (Eu2+ is incompatible in zircon) or depletion of Eu in the melt from plagioclase prior to or during zircon crystallization. We report experimental data from zircons crystallized in hydrous peralkaline, metaluminous, and peraluminous melts (800-1300oC; 10 kbar) with the oxygen fugacity buffered from ~IW to HM+1 in order to constrain magnitude of zircon Ce and Eu anomalies. Zircon Ce anomalies increase in magnitude with higher oxygen fugacities and lower crystallization temperatures; Eu anomalies are more negative at ~IW vs. NNO for the same temperature and melt composition. Our experiments also show that with the oxygen fugacity buffered at NNO, zircons may have both positive Ce anomalies and negative Eu anomalies. Thus, Eu2+ and Ce4+ may co-exist in terrestrial melts; furthermore, melt depletion of Eu by plagioclase fractionation prior to (or during) zircon crystallization may not be a requisite for the presence of zircon Eu anomalies in (Hadean) zircons. The magnitude of the anomalies is also a function of the melt composition; peraluminous melts yield the largest positive Ce (or negative Eu) anomalies at a given oxygen fugacity and temperature. Extrapolation of our preliminary empirical calibration to the crystallization temperatures of the Jack Hills Hadean zircons (~700oC) suggests the magnitude of Ce anomalies in approximately half of the Hadean zircons cannot be produced in metaluminous or peralkaline melts, even at oxygen fugacities as high as HM+1. However, the magnitude of Ce anomalies in Hadean zircons is within the range of predicted anomalies of our experiments for peraluminous melts, implying that a significant portion of the Hadean zircon population may be derived from peraluminous melts. This result is consistent with muscovite inclusion mineralogy in Hadean zircons (e.g., Hopkins et al., 2008), but does not preclude the possibility of other, less evolved peraluminous source rocks, or some process which leads to significant Ce enrichment (relative to La and/or Pr) in the melt at the time of zircon crystallization.

Trail, D.; Watson, E. B.; Tailby, N.

2010-12-01

254

Testing the Ti-in-Zircon Thermometer  

Microsoft Academic Search

Results of an empirical thermometer based on the concentration of Ti in zircon recently led Watson and Harrison (2005) to propose the existence of wet, minimum melting throughout the Hadean Eon - a hypothesis with far ranging implications. Tests of this hypothesis include: assessment of the range of validity of the thermometer, documentation of crystallization temperatures of post-Hadean granitoid zircons,

T. M. Harrison; A.-Aikman; P.-Holden; A. M. Walker; C.-McFarlane; D.-Rubatto; E. B. Watson

2005-01-01

255

Synthesis and electrical analysis of nano-crystalline barium titanate nanocomposites for use in high-energy density applications.  

SciTech Connect

Ceramic based nanocomposites have recently demonstrated the ability to provide enhanced permittivity, increased dielectric breakdown strength, and reduced electromechanical strain making them potential materials systems for high energy density applications. A systematic characterization and optimization of barium titanate and PLZT based nanoparticle composites employing a glass or polymer matrix to yield a high energy density component will be presented. 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 solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric/ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

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

2010-10-01

256

Solution Synthesis and Processing of PZT Materials for Neutron Generator Applications  

SciTech Connect

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.

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

1998-12-01

257

Multidimensional Validation Impact Tests on PZT 95/5  

NASA Astrophysics Data System (ADS)

A family of nonplanar impact tests has been conducted on the ferrelectric ceramic PZT 95/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging and multipoint VISAR (velocity interferometry). Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations. The simulations produced approximately correct attenuations and divergence, but significantly low wave velocities. Adjusting parameters improve the wave velocity agreement. Several sets of tests conducted using PZT rods (length:diameter = 5:1) encapsulated in ALOX, and diagnosed with line-imaging and point VISAR, were modeled as well.

Furnish, Michael D.; Robbins, Joshua; Trott, Wayne M.; Chhabildas, Lalit C.; Lawrence, R. Jeffery; Montgomery, Stephen T.

2001-06-01

258

Enthalpy of formation of zircon  

Microsoft Academic Search

Using high-temperature solution calorimetry in molt 2PbO {center dot} BâOâ, the enthalpy of reaction of the formation of zircon, ZrSiOâ, from its constituent oxides has been determined: ÎâHâââ(ZrSiOâ) = -27.9 ({plus minus}1.9) kJ\\/mol. With previously reported data for the heat contents of ZrOâ SiOâ and ZrSiOâ and standard-state enthalpies of formation of ZrOâ and SiOâ, we obtain Î{sub f}Hâââ°. (ZrSiOâ)

Adam J. G. Ellison; Alexandra Navrotsky

1992-01-01

259

Deposition and characterization of photoconductive PZT thin films  

Microsoft Academic Search

Deposition by the aqueous acetate solution (DAAS) technique was used to synthesize highly crystalline thin films of undoped and 2% iron-doped Pb(Zr{sub 0.53}Ti{sub 0.47})Oâ [PZT (53,47)] perovskites on sapphire and Pt substrates at 600 C. Fe ions were added either at the precursor stage or diffused thermally. The crystallization of the films was measured by X-ray diffraction. The ferroelectric activity

C. T. Lin; L. Li; J. S. Webb; M. S. Leung; R. A. Lipeles

1995-01-01

260

Octahedral tilting, monoclinic phase and the phase diagram of PZT  

Microsoft Academic Search

Anelastic and dielectric spectroscopy measurements on PbZr1-xTixO3 (PZT) close to the morphotropic (MPB) and antiferroelectric boundaries provide new insight into some controversial aspects of its phase diagram. No evidence is found of a border separating monoclinic (M) from rhombohedral (R) phases, in agreement with recent structural studies supporting a coexistence of the two phases over a broad composition range x

F. Cordero; F. Trequattrini; F. Craciun; C. Galassi

2011-01-01

261

Multidimensional Validation Impact Tests on PZT 95\\/5  

Microsoft Academic Search

A family of nonplanar impact tests has been conducted on the ferrelectric ceramic PZT 95\\/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging and multipoint VISAR (velocity interferometry). Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations.

Michael D. Furnish; Joshua Robbins; Wayne M. Trott; Lalit C. Chhabildas; R. Jeffery Lawrence; Stephen T. Montgomery

2001-01-01

262

Truss Structure Integrity Identification Using PZT Sensor-Actuator  

Microsoft Academic Search

This paper presents a frequency domain impedance-signature-based technique for health monitoring of an assembled truss structure. Unlike conventional modal analysis approaches, the technique uses piezoceramic (PZT) elements as integrated sensor-actuators for acquisition of signature pattern of the truss. The concept of the localization of sensing\\/actuation area for damage detection of an assembled structure is presented for the first time. Through

F. P. Sun; Z. Chaudhry; C. Liang; C. A. Rogers

1995-01-01

263

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

E-print Network

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- tive amounts of Ba and Sr. TC for pure barium t

Alpay, S. Pamir

264

Exploring the Seas of Titan: The Titan Mare Explorer (TiME) Mission  

Microsoft Academic Search

The Titan Mare Explorer (TiME) is a Discovery-class mission that would constrain Titan's active methane cycle as well as its intriguing prebiotic organic chemistry by providing in situ measurements from the surface of a Titan sea.

E. R. Stofan; J. I. Lunine; R. D. Lorenz; O. Aharonson; E. Bierhaus; B. Clark; C. Griffith; A.-M. Harri; E. Karkoschka; R. Kirk; B. Kantsiper; P. Mahaffy; C. Newman; M. Ravine; H. Waite; J. Zarnecki

2010-01-01

265

Ice condensation layers in Titan’s Stratosphere  

NASA Astrophysics Data System (ADS)

Photochemical destruction of methane along with the destruction of nitrogen molecules from energetic electrons in Titan’s upper atmosphere result in the production of a number of hydrocarbon and nitrile compounds which may be capable of condensing at the colder temperatures of Titan’s 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. Recently, Anderson & Samuelson (2011, Icarus, v. 212, p. 762) examined data from the Cassini Composite Infrared Spectrometer (CIRS) and found evidence for emission features centered around 90 km which are consistent with nitrile ices, notably HCN and HC3N. These compounds along with other possible contributors have been added to the Titan-CARMA column microphysics model (Barth & Toon, 2006, Icarus, v. 182, p. 230) to explore the altitudes for condensation as well as expected particle sizes in these stratospheric ice layers. Simulations show an ice layer of combined HCN and HC3N forming near 90 km, with particle sizes of microns. C2H6 and C2H2 condense out as ices in separate layers between 50 and 60 km with slightly larger particles.

Barth, Erika L.

2012-10-01

266

Carbon isotopic enrichment in Titan's tholins? Implications for Titan's aerosols  

NASA Astrophysics Data System (ADS)

Since the discovery of the main composition of Titan's atmosphere, many laboratory experiments have been carried out to mimic its chemical evolution, and more particularly the formation of the organic haze particles widespread in this atmosphere. Indeed, some of these simulation experiments produce a solid phase - named Titan's tholins - that is assumed to get properties analogous to the Titan's aerosols ones. We have studied the possible isotopic fractionation of carbon during the processes involved in the formation of Titan's tholins, using tholins obtained from different simulation experiments. It's an important issue because it can provide information on the processes of tholins formation. We will present the first results obtained on the 12 C/13 C isotopic ratios measured on Titan's tholins synthesized in laboratory with cold plasma discharges. Measurements of isotopic enhancement in 13 C (? 13 C), done both on tholins and on the initial gas mixture (N2 :CH4 (98:2)) used to produce them, do not show any clear deficit or enrichment in 13 C relatively to 12 C in the synthesised tholins, compared to the initial gas mixture. Preliminary retrieving of the data of the Aerosol Collector and Pyrolyzer (ACP) experiment of the Huygens probe suggests that Titan's aerosols may also not present carbon isotopic enrichment. This observation allows to go further in the analyses of the ACP experiment data. We are also focusing on the evolution of Titan's tholins under acid hydrolysis treatment. This strong treatment aims to reproduce the evolution of Titan's aerosols in contact with ice water under a longer time scale. Preliminary results on the analyses of the obtained products could give guides lines to identify the still unspecified matter that takes part to the Titan's surface reflectivity decrease as observed by the DISR instrument. This study is still in progress.

Nguyen, M.-J.; Raulin, F.; Coll, P.; Derenne, S.; Szopa, C.; Cernogora, G.; Israel, G.; Bernard, J.-M.

267

Design and evaluation of PZT thin-film micro-actuator for hard disk drives  

Microsoft Academic Search

A new thin-film PZT micro-actuator bonded to a stainless steel (SUS304) suspension for positioning a magnetic head for high-density hard disk devices has been designed, fabricated and investigated. This PZT micro-actuator in dual-stage serve system was made using a sol–gel technique deposited thin-film PZT and applying reactive ion etching processes to fabricate the micro-actuator. The SUS304 cantilever beam integrated with

Yang Jing; Jianbin Luo; Xiaoxing Yi; Xin Gu

2004-01-01

268

PZT\\/polymer flexible composites for embedded actuator and sensor applications  

Microsoft Academic Search

Currently, smart structures utilize both polymeric sensor and PZT-based actuators. Polymeric sensors based upon PVDF are limited to about 70 degrees C operating temperature, while PZT-based actuators are inflexible. This paper examines the use of PZT\\/polymer composites for smart materials applications. Both ferroelectric (VDF) and non- ferroelectric high temperatuer polymers were studied. High temperature composite sensors were fabricated exhibiting g31

Witold Kowbel; Xiaoxin Xia; W. Champion; James C. Withers; Ben K. Wada

1999-01-01

269

Titan impacts and escape  

NASA Astrophysics Data System (ADS)

We report on hydrodynamic calculations of impacts of large (multi-kilometer) objects on Saturn's moon Titan. We assess escape from Titan, and evaluate the hypothesis that escaping ejecta blackened the leading hemisphere of Iapetus and peppered the surface of Hyperion. We carried out two- and three-dimensional simulations of impactors ranging in size from 4 to 100 km diameter, impact velocities between 7 and 15 km s -1, and impact angles from 0° to 75° from the vertical. We used the ZEUSMP2 hydrocode for the calculations. Simulations were made using three different geometries: three-dimensional Cartesian, two-dimensional axisymmetric spherical polar, and two-dimensional plane polar. Three-dimensional Cartesian geometry calculations were carried out over a limited domain (e.g. 240 km on a side for an impactor of size di = 10 km), and the results compared to ones with the same parameters done by Artemieva and Lunine (2005); in general the comparison was good. Being computationally less demanding, two-dimensional calculations were possible for much larger domains, covering global regions of the satellite (from 800 km below Titan's surface to the exobase altitude 1700 km above the surface). Axisymmetric spherical polar calculations were carried out for vertical impacts. Two-dimensional plane-polar geometry calculations were made for both vertical and oblique impacts. In general, calculations among all three geometries gave consistent results. Our basic result is that the amount of escaping material is less than or approximately equal to the impactor mass even for the most favorable cases. Amounts of escaping material scaled most strongly as a function of velocity, with high-velocity impacts generating the largest amount, as expected. Dependence of the relative amount of escaping mass fesc = mesc/ Mi on impactor diameter di was weak. Oblique impacts (impact angle ?i > 45°) were more effective than vertical or near-vertical impacts; ratios of mesc/ Mi ˜ 1-2 were found in the simulations.

Korycansky, D. G.; Zahnle, Kevin J.

2011-01-01

270

Titan Airship Surveyor  

NASA Technical Reports Server (NTRS)

Saturn's moon Titan is considered to be one of the prime candidates for studying prebiotic materials - the substances that precede the formation of life but have disappeared from the Earth as a result of the evolution of life. A unique combination of a dense, predominantly nitrogen, atmosphere (more than four times that of the Earth), low gravity (six times less than on the Earth) and small temperature variations makes Titan the almost ideal planet for studies with lighter-than-air aerial platforms (aerobots). Moreover, since methane clouds and photochemical haze obscure the surface, low-altitude aerial platforms are the only practical means that can provide global mapping of the Titan surface at visible and infrared wavelengths. One major challenge in Titan exploration is the extremely cold atmosphere (approx. 90 K). However, current material technology the capability to operate aerobots at these very low temperatures. A second challenge is the remoteness from the Sun (10 AU) that makes the nuclear (radioisotopic) energy the only practical source of power. A third challenge is remoteness from the Earth (approx. 10 AU, two-way light-time approx. 160 min) which imposes restrictions on data rates and makes impractical any meaningful real-time control. A small-size airship (approx. 25 cu m) can carry a payload approximately 100 kg. A Stirling engine coupled to a radioisotope heat source would be the prime choice for producing both mechanical and electrical power for sensing, control, and communications. The cold atmospheric temperature makes Stirling machines especially effective. With the radioisotope power source the airship may fly with speed approximately 5 m/s for a year or more providing an excellent platform for in situ atmosphere measurements and a high-resolution remote sensing with unlimited access on a global scale. In a station-keeping mode the airship can be used for in situ studies on the surface by winching down an instrument package. Floating above the surface allows relatively simple means for flight control. Mission requirements and possible methods of navigation, control, data acquisition, and communications are discussed. The presentation describes also the state-of-the art and current progress in aerial deployed aerobots.

Kerzhanovich, V.; Yavrouian, A.; Cutts, J.; Colozza, A.; Fairbrother, D.

2001-01-01

271

Co-firing of PZN-PZT\\/Ag multilayer actuator prepared by tape-casting method  

Microsoft Academic Search

A large-area multilayer ceramic actuator composed of piezoelectrically active Pb(Zn1\\/3Nb2\\/3)0.2(Zr1\\/2Ti1\\/2)0.8 (PZN-PZT) layers and silver metal layers was fabricated by the tape-casting method. Low-temperature sinterable PZN-PZT ceramics were used as piezoelectric layers, and silver paste containing PZN-PZT ceramic frits was used as conductive inner-electrode layers. PZN-PZT powder was prepared by conventional mechanical mixing of the raw powders in ethanol. The green

Jong-Jin Choi; Joo-Hee Lee; Byung-Dong Hahn; Woon-Ha Yoon; Dong-Soo Park

2008-01-01

272

Ice layers in Titan's stratosphere  

NASA Astrophysics Data System (ADS)

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 in the colder temperatures of Titan’s 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 serve as condensation nuclei. Recently, Anderson & Samuelson (2011, Icarus, v. 212, p. 762) looked at data from the Cassini Composite Infrared Spectrometer (CIRS) and found evidence for emission features centered around 90 km which are consistent with nitrile ices, notably HCN and HC3N. These compounds along with other possible contributors have been added to the Titan-CARMA column microphysics model (Barth & Toon, 2006, Icarus, v. 182, p. 230) to explore altitudes for condensation as well as expected particle sizes in these stratospheric ice layers.

Barth, E. L.

2012-04-01

273

Ti-in-zircon thermometry: applications and limitations  

Microsoft Academic Search

The titanium concentrations of 484 zircons with U-Pb ages of ?1 Ma to 4.4 Ga were measured by ion microprobe. Samples come\\u000a from 45 different igneous rocks (365 zircons), as well as zircon megacrysts (84) from kimberlite, Early Archean detrital zircons\\u000a (32), and zircon reference materials (3). Samples were chosen to represent a large range of igneous rock compositions. Most\\u000a of the

Bin Fu; F. Zeb Page; Aaron J. Cavosie; John Fournelle; Noriko T. Kita; Jade Star Lackey; Simon A. Wilde; John W. Valley

2008-01-01

274

Thermoelectricity in strontium titanate  

NASA Astrophysics Data System (ADS)

This dissertation treats the synthesis, experimental characterization, thermoelectric properties, potential applications of, and theoretical basis for strontium titanate thermoelectric materials. It is found that doubly-doped strontium titanate, Sr1-xLaxTiO3-d is an efficient n-type thermoelectric material, yielding a dimensionless thermoelectric figure of merit zT higher than other oxides and among the highest of any thermoelectric material in general. The improvement in thermoelectric efficiency of this material over other oxides is attributed in large part to the oxygen vacancy, which increases the electronic effective mass m* and in turn thermopower, increases electrical conductivity through donating electrons, and decreases lattice thermal conductivity. Through proper selection of La and oxygen vacancy doping, m* can be tuned in the material in the range of 2-20 me and thermal conductivity reduced by over a factor of three compared to stoichiometric SrTiO3. The potential applications of thin-film thermoelectrics in energy conversion are explored. In addition, the remarkable oxygen reduction of SrTiO3 single-crystal substrates is reported as resulting from pulsed laser deposition growth of oxide thin-films on their surfaces.

Scullin, Matthew Leo

275

New experimental constraints for Hadean zircon source melts from Ce and Eu anomalies in zircon  

Microsoft Academic Search

A common feature of zircon rare earth element profiles is that they often have enriched chondrite normalized Ce abundances relative to bracketing rare earth elements (REEs) La and Pr. The magnitude of a zircon Ce anomaly is generally attributed to an increase in Ce4+\\/Ce3+ of the crystallizing medium (Ce4+ is more compatible than Ce3+ in zircon), which is associated with

D. Trail; E. B. Watson; N. Tailby

2010-01-01

276

Ti-in-Zircon Thermometer: Preliminary Results  

NASA Astrophysics Data System (ADS)

The titanium in zircon thermometer has been applied to 167 zircons from diverse rock types. These rocks include metamorphosed anorthosite and gabbro (1.15 Ga, intrusion age), and unmetamorphosed granitic pegmatite (0.9 Ga) from the Adirondack Highlands; metaluminous and peraluminous granites (114-90 Ma) of the Sierra Nevada Batholith; megacrysts from kimberlite pipes in southern Africa, Brazil, and Siberia; and detrital zircons (4.4-3.9 Ga) of metaconglomerate from Jack Hills, Western Australia. Titanium concentration in zircon was analysed using a CAMECA IMS-1280 ion microprobe (see Page et al., this volume). Spot analyses were correlated to U-Pb SHRIMP pits especially for Adirondack and Jack Hills zircons. The majority of zircons have Ti-content less than 10 ppm. Variability, in excess of analytical precision, within individual zircons is observed in about one-third of crystals. In general, there is no systematic change in Ti from core to rim (identified by cathodoluminescence) of zircons, or with regard to age, U content, Th/U ratio, or U-Pb age concordance for these non-metamict grains. The average temperatures for zircon crystallization in different rock suites using the experimental/empirical calibration of Watson and Harrison (W&H, 2005, Science 308:841), assuming the presence of rutile and quartz, are estimated to be: anorthosite 735±41°C (1SD, n=24; Ti = 10±5 ppm); metagabbro 714±31°C (n=19; Ti = 8±4 ppm); Adirondack pegmatite 500±16°C (n=5; Ti = 0.3±0.1 ppm); metaluminous and peraluminous granites from Sierra Nevada 681±67°C (n=53; Ti = 6±5 ppm) and 613±75°C (n=68; Ti = 3±3 ppm); kimberlite megacrysts 740±64°C (n=169; Ti = 14±13 ppm) (Page et al., this volume); and detrital zircons from Jack Hills metaconglomerate 718±63°C (n=64; Ti = 10±9 ppm). Most of the host rocks contain ilmenite or titanite suggesting that ?(TiO2)>0.5, but rutile activity is unknown for megacrysts and detrital zircons. Pegmatite contains no Ti-rich minerals, permissive of low rutile activity. Peraluminous granites have lower whole-rock TiO2 content (0.02-0.21 wt.%) than metaluminous granites (0.54-0.91 wt.%), and both have similar zircon saturation temperatures (710-780°C). The low Ti content and apparent temperature in zircons from anorthosite and metagabbro (magmatic T = ca. 1000-1100°C) and the homogeneity of igneous zircon cores vs. metamorphic rims in metagabbro suggest that Ti content was reset during granulite-facies metamorphism (750°C, 1.0 Ga), in contrast to the current estimate of extremely low diffusivity of Ti in zircon. The Ti contents of >3.9 Ga Jack Hills detrital zircons are consistent with previously published data that were used to constrain magmatic temperature and thus the composition of unknown host rocks (W&H, 2005, Science 308:841). However, these values overlap those from both felsic and mafic rocks, and the Ti data are not sufficient to independently identify parent melt chemistry unless post-crystallization changes can be ruled out. The best evidence of pre-4 Ga evolved crust is provided by previously reported oxygen isotope ratios and felsic mineral inclusions in zircon (see Cavosie et al., 2005, EPSL 235:663).

Fu, B.; Cavosie, A. J.; Clechenko, C. C.; Fournelle, J.; Kita, N. T.; Lackey, J.; Page, F.; Wilde, S. A.; Valley, J. W.

2005-12-01

277

Carbon isotopic enrichment in Titan's Tholins: implications for Titan's aerosols  

NASA Astrophysics Data System (ADS)

Since the discovery of the main composition of Titan s atmosphere many laboratory experiments have been carried out to mimic its chemical evolution and in particular the formation of the haze particles of this atmosphere Indeed the solid products obtained during these simulation experiments -- often named Titan s tholins -- are supposed to be analogues of Titan s aerosols and many studies have already been achieved on these tholins We have studied the possible isotopic fractionation of carbon during the processes involved in the formation of Titan s tholins using tholins obtained from different simulation experiments We will present the first results obtained on the isotopic ratios of 13 C 12 C measured on the analogues of Titan s aerosols synthesized in laboratory Measurement of delta 13 C leaded both on laboratory aerosols and on the initial gas mixture N 2 CH 4 98 2 used in the simulations doesn t show any evident deficit or enrichment of 13 C in comparison with 12 C in the aerosols synthesised compared to the initial gas mixture Preliminary retrieving of the data of the ACP instrument on the Huygens probe suggests that Titan s aerosols may present also no enrichment This allows us to go further in the analyses of the ACP data in comparison with the first conclusions newly published in Nature Isra e l et al Nature 2005

Nguyen, N.; Raulin, R.; Coll, C.; Derenne, D.; Szopa, S.; Israël, I.; Cernogora, C.; Bernard, B.

278

The TITAN reversed-field-pinch fusion reactor study  

SciTech Connect

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.

Not Available

1990-01-01

279

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

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

280

Titan's greenhouse and antigreenhouse effects  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

281

Seasonal Changes in Titan's Meteorology  

NASA Technical Reports Server (NTRS)

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

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

282

Corona chemistry in Titan.  

PubMed

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 charged particles leads to corona discharges which are characterized by low current densities. 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-butane, 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 a highly branched hydrocarbon deposit. We present the trends of hydrocarbons and nitriles formation as a function of discharge time in an ample interval and have derived their initial yields of formation. The 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 too low by a factor of 10 to 40. While some ethene will be produced by charged-particle chemistry, the production of ethene by corona processes and its 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. PMID:11541887

Navarro-Gonzalez, R; Ramirez, S I; Matrajt, G; Basiuk, V; Basiuk, E

1998-06-01

283

NOVA Online: Titanic's Lost Sister  

NSDL National Science Digital Library

Companion site to an original broadcast on January 28, 1997. When Titanic sank, construction on her sister ship, Britannic, was interrupted so she could be overhauled with new regulations. Britannic sank in 1916 in less than an hour. Includes interview with Robert Ballard, who found the sunken Titanic, an interactive search, and salvage activity. Others resources available: written transcript, teacher's guide, students activities, and links to additional resources.

284

Titan's rotation - Surface feature observed  

NASA Astrophysics Data System (ADS)

A surface feature or a near-surface fracture is suggested to account for the time variations in the 0.94, 1.08, and 1.28 micron atmospheric windows of Titan's geometric albedo, relative to its albedo in adjacent methane bands. These observations are noted to be consistent with synchronous rotation. They can also be explained by a 0.1-higher surface albedo on Titan's leading hemisphere.

Lemmon, M. T.; Karkoschka, E.; Tomasko, M.

1993-06-01

285

Isotopic Composition of Oxygen in Lunar Zircons  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

286

Shock Recrystallisation and Decomposition of Zircon  

NASA Astrophysics Data System (ADS)

In this study, we present the first electron backscatter diffraction (EBSD) characterization of granular and decomposed zircon in order to investigate the mechanism(s) by which these microstructures are produced.

Timms, N. E.; Erickson, T. E.; Schmieder, M.; Tohver, E.

2014-09-01

287

Testing the Ti-in-Zircon Thermometer  

NASA Astrophysics Data System (ADS)

Results of an empirical thermometer based on the concentration of Ti in zircon recently led Watson and Harrison (2005) to propose the existence of wet, minimum melting throughout the Hadean Eon - a hypothesis with far ranging implications. Tests of this hypothesis include: assessment of the range of validity of the thermometer, documentation of crystallization temperatures of post-Hadean granitoid zircons, and replication of the ca. 680°C} peak temperature of Hadean zircons. We have probed the energies of the isovalent substitution of Ti on the Si and Zr sites in zircon using the SIESTA implementation of density functional theory which uses pseudopotentials to describe the core electrons and nuclei, and a numerical scheme to describe valence electrons which allows large numbers of atoms to be assessed. Results show that the substitution of Ti on the Si site is highly favoured over the competing mechanism by approximately 32 kJ/mol. Thus essentially all Ti is expected to occupy the Si site in the zircon crystal structure in the temperature range over which the thermometer has been calibrated thus explaining in part the observed linear behaviour. We have developed a SHRIMP multi-collector protocol for zircon utilizing 49Ti/SiO which yields <0.5% precision for Ti concentrations down to the ppm level. Analysis of zircons from rutile-bearing metmorphic rocks constrained by thermobarometry to have formed between 550 and 800°C} yield calculated temperatures within uncertainty of the known value, further confirming the general validity of the thermometer in that temperature range. Analyses of a variety of granitoids including tonalite yield calculated temperatures ranging up to 820°C} that broadly correlate with zircon saturation temperature. Thus we infer that calculated temperatures of <700°C} from granitoid zircons are generally restricted to water-saturated melting conditions. We have revisited the Hadean zircons of Jack Hills, Western Australia, and more than doubled the number of Ti analyses. Of the 136 total analyses of zircons ranging in age from 3.91-4.35 Ga, only seven yield calculated temperatures in excess of 800°C}. The vast majority of analyses instead plot in a normal distribution with a peak at 680 ± 20°C}. Together with results from other studies (e.g., O isotopes, Lu-Hf, inclusion mineralogy) we conclude that the Hadean Earth supported wet, minimum melting, the formation of clay minerals under ambient conditions, and peraluminous melting of pelitic protoliths. Current analytical developments involve ion imaging Ti concentration variations using 48Ti at high mass resolving power.

Harrison, T. M.; Aikman, A.-; Holden, P.-; Walker, A. M.; McFarlane, C.-; Rubatto, D.-; Watson, E. B.

2005-12-01

288

Seasonal variations on Titan  

NASA Astrophysics Data System (ADS)

Eight years after Cassini's Saturn orbit insertion, we look at the evolution of the thermal and chemical composition of Titan's atmosphere by combining Cassini CIRS recordings and the related ground- and space- based observations The fulfillment of one Titanian year of observations provides us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment. By comparing V1 (1980), ISO (1997) and Cassini (2010) we find that a reversal of composition near the equator from automnal equinox to vernal equinox (1996 min -2009 max, half a year), as well as some differences in polar enhancement at the same era as Voyager.

Coustenis, A.; Bampasidis, G.; Vinatier, S.; Achterberg, R.; Lavvas, P.; Nixon, C.; Jennings, D.; Teanby, N.; Flasar, F. M.; Carlson, R.; Orton, G.; Romani, P.; Guandique, E. A.

2012-09-01

289

Life on Titan  

NASA Astrophysics Data System (ADS)

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

Potashko, Oleksandr

290

Chemistry in Titan  

NASA Astrophysics Data System (ADS)

Modelling the chemical composition of Titan's ionosphere is a very challenging issue. Latest works perform either inversion of CASSINI's INMS mass spectra (neutral[1] or ion[2]), or design coupled ion-neutral chemistry models[3]. Coupling ionic and neutral chemistry has been reported to be an essential feature of accurate modelling[3]. Electron Dissociative Recombination (EDR), where free electrons recombine with positive ions to produce neutral species, is a key component of ion-neutral coupling. There is a major difficulty in EDR modelling: for heavy ions, the distribution of neutral products is incompletely characterized by experiments. For instance, for some hydrocarbon ions only the carbon repartition is measured, leaving the hydrogen repartition and thus the exact neutral species identity unknown[4]. This precludes reliable deterministic modelling of this process and of ion-neutral coupling. We propose a novel stochastic description of the EDR chemical reactions which enables efficient representation and simulation of the partial experimental knowledge. The description of products distribution in multi-pathways reactions is based on branching ratios, which should sum to unity. The keystone of our approach is the design of a probability density function accounting for all available informations and physical constrains. This is done by Dirichlet modelling which enables one to sample random variables whose sum is constant[5]. The specifics of EDR partial uncertainty call for a hierarchiral Dirichlet representation, which generalizes our previous work[5]. We present results on the importance of ion-neutral coupling based on our stochastic model. C repartition H repartition (measured) (unknown ) â?? C4H2 + 3H2 + H .. -â?? C4 . â?? C4H2 + 7H â?? C3H8. + CH C4H+9 + e- -â?? C3 + C .. â?? C3H3 + CH2 + 2H2 â?? C2H6 + C2H2 + H .. -â?? C2 + C2 . â?? 2C2H2 + 2H2 + H (1) References [1] J. Cui, R.V. Yelle, V. Vuitton, J.H. Waite Jr., W.T. Kasprzak, D.A. Gell, H.B. Niemann, I.C.F. Müller-Wodarg, N. Borggren, G.G. Fletcher, E.L. Patrick, E. Raaen, and B.A. Magee. Analysis of Titan's neutral upper atmosphere from Cassini ion neutral mass spectrometer measurements. Icarus, In Press, Accepted Manuscript:-, 2008. [2] V. Vuitton, R. V. Yelle, and M.J. McEwan. Ion chemistry and N-containing molecules in Titan's upper atmosphere. Icarus, 191:722-742, 2007. [3] V. De La Haye, J.H. Waite Jr., T.E. Cravens, I.P. Robertson, and S. Lebonnois. Coupled ion and neutral rotating model of Titan's upper atmosphere. Icarus, 197(1):110 - 136, 2008. [4] J. B. A. Mitchell, C. Rebrion-Rowe, J. L. Le Garrec, G. Angelova, H. Bluhme, K. Seiersen, and L. H. Andersen. Branching ratios for the dissociative recombination of hydrocarbon ions. I: The cases of C4H9+ and C4H5+. International Journal of Mass Spectrometry, 227(2):273-279, June 2003. [5] N. Carrasco and P. Pernot. Modeling of branching ratio uncertainty in chemical networks by Dirichlet distributions. Journal of Physical Chemistry A, 11(18):3507-3512, 2007.

Plessis, S.; Carrasco, N.; Pernot, P.

2009-04-01

291

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

E-print Network

Ferroelectric PZT RF MEMS Resonators Jeffrey S. Pulskamp, Sarah S. Bedair, Ronald G. Polcawich Engineering Cornell University Ithaca, NY, USA Abstract--This paper presents recent work on ferroelectric]. Due to the strong piezoelectric effect in PZT, actuators are capable of very large force generation

Afshari, Ehsan

292

Height-related magnetoelectric performance of PZT/Ni layered composites  

E-print Network

Height-related magnetoelectric performance of PZT/Ni layered composites Zhi-Jun Zuo, De-An Pan*, Li-Verlag Berlin Heidelberg 2014 Abstract The effect of height on performance of the PZT/Ni cylindrical bilayered and 300 kHz frequency for cyl- inders of different heights. The first resonance frequency does not change

Volinsky, Alex A.

293

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

NASA Astrophysics Data System (ADS)

Zircons found in mantle-sourced kimberlite provide probes into the isotopic chemistry of the asthenosphere and subcontinental lithospheric mantle. However, little is known about the conditions of formation of these zircons. A suite of 88 zircons found in kimberlites from Africa, Siberia, Brazil, and the United States have been analyzed for their Ti concentration and selected zircons were analyzed for their Rare Earth Element (REE) concentrations by ion microprobe. In addition, precise and accurate laser-fluorination oxygen isotope data were obtained for zircons from Brazil (5.1 ± 0.3‰, 1SD) and the Midwest United States (5.3 ± 0.3‰), yielding mantle-like ? 18O values similar to published data for Africa (5.2 ± 0.3‰) and Siberia (5.3 ± 0.2‰). Most megacrysts in this study preserve fine-scale, oscillatory zoning in CL and are generally homogenous in oxygen isotopic composition, consistent with preservation of primary compositions. A few zircons from Brazil show some evidence of chemical zoning due to recrystallization. The Ti content of mantle zircon is in general low with average compositions from each locality of 13 ± 8.4 ppm (1SD, Kaapvaal craton), 12 ± 8.7 ppm (Siberian platform), 18 ± 11 ppm (Brazil), and 4.8 ±4.3 ppm (United States). The recently calibrated Ti in zircon thermometer yields an average temperature of 744 ±62 °C (1SD) for the average of 13 ± 9 ppm Ti, with no correction for pressure, aTiO 2, or aSiO 2. The Ti content of zircons found within rutile nodules from the Orapa kimberlite (Kaapvaal craton) is almost indistinguishable from those with no constraint on aTiO 2, suggesting that reduced aTiO 2 is not responsible for lower than expected mantle temperatures. The average temperature in this study corresponds to ˜3 GPa on a 40 mW/m 2 cratonic geotherm. If correct, this would suggest that zircon megacrysts from all four cratons formed in the shallow lithospheric mantle. However, there are several possibly confounding effects to this thermometer, including: a pressure correction and disequilibrium zircon growth. Zircons from rutile nodules have REE contents that span the range of mantle zircon REE and are similar to both zircon megacrysts and zircons from metasomatic assemblages.

Page, F. Zeb; Fu, Bin; Kita, Noriko T.; Fournelle, John; Spicuzza, Michael J.; Schulze, Daniel J.; Viljoen, Fanus; Basei, Miguel A. S.; Valley, John W.

2007-08-01

294

Simulations of Titan's paleoclimate  

NASA Astrophysics Data System (ADS)

We investigate the effects of varying Saturn's orbit on the atmospheric circulation and surface methane distribution of Titan. Using a new general circulation model of Titan's atmosphere, we simulate its climate under four characteristic configurations of orbital parameters that correspond to snapshots over the past 42 kyr, capturing the amplitude range of long-period cyclic variations in eccentricity and longitude of perihelion. The model, which covers pressures from the surface to 0.5 mbar, reproduces the present-day temperature profile and tropospheric superrotation. In all four simulations, the atmosphere efficiently transports methane poleward, drying out the low- and mid-latitudes, indicating that these regions have been desert-like for at least tens of thousands of years. Though circulation patterns are not significantly different, the amount of surface methane that builds up over either pole strongly depends on the insolation distribution; in the present-day, methane builds up preferentially in the north, in agreement with observations, where summer is milder but longer. The same is true, to a lesser extent, for the configuration 14 kyr ago, while the south pole gains more methane in the case for 28 kyr ago, and the system is almost symmetric 42 kyr ago. This confirms the hypothesis that orbital forcing influences the distribution of surface liquids, and that the current observed asymmetry could have been partially or fully reversed in the past. The evolution of the orbital forcing implies that the surface reservoir is transported on timescales of ?30 kyr, in which case the asymmetry reverses with a period of ?125 kyr. Otherwise, the orbital forcing does not produce a net asymmetry over longer timescales, and is not a likely mechanism for generating the observed dichotomy.

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

2014-11-01

295

Effect of substrate bending on the piezoelectric measurement of PZT thin film  

NASA Astrophysics Data System (ADS)

Bonding conditions between PZT thin film and sample holder greatly affect the strain measurement of the PZT sample. The influence of various bonding conditions on the measured displacement were analyzed using finite element analysis (FEA). One-end fixed sample induces the maximum bending displacement. Experiments were performed on sol-gel derived PZT thin film. The voltage-displacement curve and "butterfly" loop were measured using laser Doppler method with phase detection. Experimental results agreed well with the simulated ones. The measured frequency dependence of piezoelectric response of PZT thin film indicated that, if the operating frequency was lower than 2 kHz, good bonding effect could be obtained when the entire back surface of the sample was glued to a rigid supporter using epoxy resin. A simple bonding model which considered the adhesives as a spring was used to estimate the frequency response of PZT thin film sample.

Xu, Xiaohui; Tang, Jianhong; He, Liangna

2009-05-01

296

Planetary science: Titan's lost seas found  

NASA Astrophysics Data System (ADS)

When the Cassini spacecraft found no methane ocean swathing Saturn's moon Titan, it was a blow to proponents of an Earth-like world. The discovery of northern lakes on Titan gives them reason for cheer.

Sotin, Christophe

2007-01-01

297

Carbon isotopic enrichment in Titan's tholins? Implications for Titan's aerosols  

NASA Astrophysics Data System (ADS)

Since the discovery of the main composition of Titan's atmosphere, many laboratory experiments have been carried out to reproduce its chemical evolution, particularly the formation of organic haze particles found throughout this atmosphere. Some of these simulations have produced solid products - referred to as Titan's tholins - that are assumed to have properties similar to those of Titan's aerosols. In the present work, we focus on the possible isotopic fractionation of carbon during the processes involved in the formation of Titan's tholins. Initial 12C/ 13C isotopic ratios measured on tholins made in the laboratory using cold plasma discharges are presented. Measurements of isotopic enhancement in 13C ( ?13C), both on tholins and on the initial gas mixture (N 2:CH 4 (98:2)) used to produce them do not show any clear deficit or enrichment in 13C relative to 12C in the lab-made tholins compared to the initial gas mixture. Preliminary data recovered from the Aerosol Collector Pyrolyzer (ACP) experiment of the Huygens probe suggests that Titan's aerosols may also be exempt of carbon isotopic enrichment. This observation creates possibilities for deeper analysis of ACP experiment data.

Nguyen, M.-J.; Raulin, F.; Coll, P.; Derenne, S.; Szopa, C.; Cernogora, G.; Israël, G.; Bernard, J.-M.

2007-11-01

298

Mapping of Titan: Results from the first Titan radar passes  

USGS Publications Warehouse

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.

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

299

Tidal Winds on Titan Caused by Saturn  

Microsoft Academic Search

The influence of Saturn's gravitational tide on the atmosphere of Titan is investigated by means of a three-dimensional general circulation model. Titan's orbital eccentricity of 0.0292 gives rise to time-dependent radial and librational tide whose potential circles eastward on Titan. Unlike atmospheric tides on terrestrial planets, Saturn's tide on Titan has a large impact on the dynamic meteorology down to

Tetsuya Tokano; Fritz M. Neubauer

2002-01-01

300

Deposition and characterization of photoconductive PZT thin films  

SciTech Connect

Deposition by the aqueous acetate solution (DAAS) technique was used to synthesize highly crystalline thin films of undoped and 2% iron-doped Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3} [PZT (53,47)] perovskites on sapphire and Pt substrates at 600 C. Fe ions were added either at the precursor stage or diffused thermally. The crystallization of the films was measured by X-ray diffraction. The ferroelectric activity was examined by polarization-voltage hysteresis (P-E) loops. The electro-optical properties of ferroelectric/photoconductive PZT thin films were investigated by excitation photocurrent spectroscopy (EPS) and 77 K emission spectroscopy. The photoconductivity measured at visible wavelengths was enhanced for the thermally diffused, but not the precursor-processed doped materials. This, together with lattice parameters obtained from X-ray data and P-E hysteresis loop measurements, suggested that the precursor-processed doped ions are strongly bonded in the perovskite lattice, whereas the thermally diffused ions are bound more weakly in the grain boundaries.

Lin, C.T.; Li, L.; Webb, J.S. [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Chemistry; Leung, M.S.; Lipeles, R.A. [Aerospace Corp., Los Angeles, CA (United States)

1995-06-01

301

Crack detection of railway turnouts using PZT sensors (presentation video)  

NASA Astrophysics Data System (ADS)

Railway turnouts (railroad switches) are the weakest components of a rail track system. Cracks may occur in the railway turnouts due to cyclic loadings and impact loadings imposed by passing trains. It is of great significance to continuously monitor the health condition of the railway turnouts and promptly detect crack once it initiates. It is well-known that acoustic emission (AE) signals are generated when a crack initiates and propagates. Detecting the high-frequency AE signals by piezoelectric sensors can help identify the crack and its location. This paper reports the design and implementation of a PZT-based system for crack monitoring of railway turnouts. This online monitoring system is activated for signal collection by a trigger system when a train is arriving to pass through the instrumented railway turnout. It mainly detects the AE signals generated when a crack initiates during the train passage or when the initiated crack expands during the passage of a heavy haul wagon. This system has been installed on a railroad line for over one year and has successfully detected the damage occurring at a railroad switch during its service period. This paper also briefs a guided-wave-based system for monitoring of micro-cracks in rail tracks by integrating FBG and PZT sensors.

Ni, Yiqing; Li, Z. G.; Wu, F.

2014-05-01

302

No more blind dates with zircon!  

NASA Astrophysics Data System (ADS)

For ion probe zircon dating of complex samples it is important to understand the stratigraphic makeup and petrogenetic history of the rock and zircon. Our approach uses cathodoluminescent (CL) or backscattered electron (BSE) images, combined with microbeam trace element analyses by LA-ICPMS or SIMS. Geochemical and textural criteria for petrogenesis are based on a number of case studies. The main criteria are CL-character and relationships of domains, Th/U ratios and Ce anomalies in REE profiles. Following a theoretical analysis, three petrological environments are defined in which zircon develops specific characteristics. (1) In SILICATE LIQUIDS such as granite or diorite intrusions, zircon grows from or interacts with only a small magma volume limited by bulk diffusion rates and trace element partition is controlled by local effects. Oscillatory zonation develops in Si-rich magmas due to different uptake and supply rates of U etc. Xenocrysts develop U-rich, CL-dark rims by reworking or new growth. Positive Ce anomalies reflect local oxidation, driven by site-size preference for the smaller 4+ ion and isolated from Fe-buffering. Zircon Th/U ratios approach magmatic as the interaction volume does not equilibrate with other minerals. Total Pb-loss from CL-bright xenocryst cores can occur, given temperatures around 1000 C and sufficient time. (2) In METAMORPHIC ENVIRONMENTS with no melt present, zircon grows from or interacts with the fluids in grain-boundaries. Fast diffusion rates mean that the zircon equilibrates with a large area of solid minerals. Unzoned CL-bright (low-U) or dark (U>300 ppm) zircon develops as other minerals release Zr and U. In samples containing detrital grains, new zircon rims truncate oscillatory zonation. Reworking follows grain boundaries or cracks. Ce oxidation and Ce anomalies in zircon are prevented by the buffering effect of iron. Minerals like monazite in the paragenesis usually deplete the fluid in Th, leading to Th/U ratios below 0.1 in zircon. (3) In HYBRID ENVIRONMENTS with silicate magma, fluid and minerals in effective contact, all phases influence the growth or reworking of zircon. Migmatites, igneous hybrids, late-stage magmatic intrusions and pegmatites are examples. Oscillatory zonation may develop in pegmatites. Existing grains develop U-rich, CL-dark rims by reworking or new growth. REE profiles with positive Ce anomalies persist in cores and (U-Th-Pb-) reworked rims due to slow REE diffusion. In new growth, Ce oxidation and anomalies are prevented by Fe-buffering in the paragenesis. Th/U diffusion rates are significant and ratios are below 0.1 in both reworked and new zircon, because the large interaction volume is depleted in Th by other minerals. Older cores retain their U-Pb age, but reworked rims are reset by total Pb loss. This scheme should be used to interpret difficult samples. Exceptions must be petrologically well-justified, it is not sufficient just to say that zircon is "igneous" or "metamorphic"! No more blind dates?

Cornell, D. H.; Austin Hegardt, E.

2003-04-01

303

Geochemical signatures and magmatic stability of terrestrial impact produced zircon  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

304

Molecular dynamics simulation of disordered zircon  

NASA Astrophysics Data System (ADS)

The melting of zircon and the amorphous state produced by quenching from the melt were simulated by molecular dynamics using a partial charge model combined with the Ziegler-Biersack-Littmark potential. The model has been established for the description of the crystalline and aperiodic structures of zircon in order to be used for the simulation of displacement cascades. It provides an excellent fit to the structure, and accounts with convenient precision for the mechanical and thermodynamic properties of zircon. The calculated melting temperature is about 2100 K. The activation energy for self-diffusion of ions in the liquid state was determined to be 190 200 kJ/mole. Melt quenching was employed to produce two different disordered states with distinct densities and structures. In the high density disordered state, the zircon structure is intact but the bond angle distributions are broader, 4% of the Si units are polymerized, and the volume swelling is about 8%. In the low density amorphous state, the Zr and Si coordination numbers are lower, and the Zr-O and Si-O bond lengths are shorter than corresponding values for the crystal. In addition, a highly polymerized Si network, with an average connectivity of 2, is observed in the low density amorphous state. These features have all been experimentally observed in natural metamict zircon. The present findings, when considered in light of experimental radiation effects studies, suggest that the swelling in zircon arises initially from disorder in the zircon crystal, and at high doses the disordered crystal is unable to accommodate the volume expansion and transforms to the amorphous state.

Devanathan, R.; Corrales, L. R.; Weber, W. J.; Chartier, A.; Meis, C.

2004-02-01

305

Imaging of Titan from the Cassini spacecraft  

Microsoft Academic Search

Titan, the largest moon of Saturn, is the only satellite in the Solar System with a substantial atmosphere. The atmosphere is poorly understood and obscures the surface, leading to intense speculation about Titan's nature. Here we present observations of Titan from the imaging science experiment onboard the Cassini spacecraft that address some of these issues. The images reveal intricate surface

Carolyn C. Porco; Emily Baker; John Barbara; Kevin Beurle; Andre Brahic; Joseph A. Burns; Sebastien Charnoz; Nick Cooper; Douglas D. Dawson; Anthony D. Del Genio; Tilmann Denk; Luke Dones; Ulyana Dyudina; Michael W. Evans; Stephanie Fussner; Bernd Giese; Kevin Grazier; Paul Helfenstein; Andrew P. Ingersoll; Robert A. Jacobson; Torrence V. Johnson; Alfred McEwen; Carl D. Murray; Gerhard Neukum; William M. Owen; Jason Perry; Thomas Roatsch; Joseph Spitale; Steven Squyres; Peter Thomas; Matthew Tiscareno; Elizabeth P. Turtle; Ashwin R. Vasavada; Joseph Veverka; Roland Wagner; Robert West

2005-01-01

306

Organic chemistry on Titan: Surface interactions  

Microsoft Academic Search

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

W. Reid Thompson; Carl Sagan

1992-01-01

307

Sputtering and heating of Titan's upper atmosphere  

E-print Network

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

Johnson, Robert E.

308

Haze Transport in Titan's Stratosphere  

NASA Astrophysics Data System (ADS)

We continue development of a new Titan General Circulation Model (GCM) using the Flexible Modeling System (FMS) dynamical core from the Geophysical Fluid Dynamics Laboratory (GFDL). The FMS core is state-of-the-art and conserves angular momentum better than other existing dynamical cores which is especially important for modeling Titan's thick atmosphere. Furthermore, an aerosol microphysics package has been developed and linked to the core model. This microphysics is based on the modified version of the Community and Radiation Model for Atmospheres (CARMA) used to study haze and cloud physical processes in Titan's atmosphere [1], [2]. The model also uses a radiative transfer package that is based on the correlated-k two-stream model of [3].

Barth, E. L.; Michaels, T. I.

2011-10-01

309

Little Drops of (Ocean) Water, Little Grains of (Zircon) Sand  

Microsoft Academic Search

Little detrital grains of zircon in the ~3 Ga Jack Hills metaconglomerate yield concordant U-Pb ages up to 4.4 Ga and provide the only direct evidence of conditions on the Early Earth. Parent rocks were destroyed by weathering and erosion; ages >4 Ga are known only from isolated zircons. These zircons and their mineral inclusions represent very small rocks and

J. W. Valley; C. B. Grimes; D. M. Ortiz; T. Ushikubo; A. Bouvier; N. Kita; A. J. Cavosie

2009-01-01

310

Will Titan lose its veil?  

NASA Astrophysics Data System (ADS)

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).

Dimitrov, V.

2007-08-01

311

Interaction of Titan's atmosphere with Saturn's magnetosphere  

NASA Technical Reports Server (NTRS)

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

Hartle, R. E.

1985-01-01

312

Zircon Th/U ratios in magmatic environs  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

313

Trace-element composition of hydrothermal zircon and the alteration of Hadean zircon from the Jack Hills, Australia  

Microsoft Academic Search

Hydrothermal zircon can be used to date fluid-infiltration events and water\\/rock interaction. At the Boggy Plain zoned pluton (BPZP), eastern Australia, hydrothermal zircon occurs with hydrothermal scheelite, molybdenite, thorite and rutile in incipiently altered aplite and monzogranite. The hydrothermal zircon is texturally distinct from magmatic zircon in the same rocks, occurring as murky-brown translucent 20–50 ?m-thick mantles on magmatic cores

Paul W. O. Hoskin

2005-01-01

314

Trace-element composition of hydrothermal zircon and the alteration of Hadean zircon from the Jack Hills, Australia  

Microsoft Academic Search

Hydrothermal zircon can be used to date fluid-infiltration events and water\\/rock interaction. At the Boggy Plain zoned pluton (BPZP), eastern Australia, hydrothermal zircon occurs with hydrothermal scheelite, molybdenite, thorite and rutile in incipiently altered aplite and monzogranite. The hydrothermal zircon is texturally distinct from magmatic zircon in the same rocks, occurring as murky-brown translucent 20 50 mum-thick mantles on magmatic

Paul W. O. Hoskin

2005-01-01

315

Fission track dating of kimberlitic zircons  

USGS Publications Warehouse

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.

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

1983-01-01

316

Anomalous radar backscatter from Titan’s surface?  

NASA Astrophysics Data System (ADS)

Since Cassini arrived at Saturn in 2004, its moon Titan has been thoroughly mapped by the RADAR instrument at 2-cm wavelength, in both active and passive modes. Some regions on Titan, including Xanadu and various bright hummocky bright terrains, contain surfaces that are among the most radar-bright encountered in the Solar System. This high brightness has been generally attributed to volume scattering processes in the inhomogeneous, low-loss medium expected for a cold, icy satellite surface. We can test this assumption now that the emissivity has been obtained from the concurrent radiometric measurements for nearly all the surface, with unprecedented accuracy (Janssen et al., and the Cassini RADAR Team [2009]. Icarus 200, 222-239). Kirchhoff’s law of thermal radiation relates the radar and radiometric properties in a way that has never been fully exploited. In this paper we examine here how this law may be applied in this case to better understand the nature of Titan’s radar-bright regions. We develop a quantitative model that, when compared to the observational data, allows us to conclude that either the reflective characteristics of the putative volume scattering subsurface must be highly constrained, or, more likely, organized structure on or in the surface is present that enhances the backscatter.

Janssen, M. A.; Le Gall, A.; Wye, L. C.

2011-03-01

317

Cratering on Titan and implications for Titan's atmospheric history  

Microsoft Academic Search

A means for putting limits on the history of Titan's atmosphere is proposed by considering the breakup of bolides during atmospheric entry and the resulting modification of the crater size-frequency distribution at the surface, which will be determined by radar during the Cassini-Huygens mission. Bolides entering the atmosphere experience forces that eventually exceed the body's strength and disruption occurs. The

Steffi Engel; Jonathan I. Lunine; William K. Hartmann

1995-01-01

318

Alpine zircon fission-track ages in the Rhne and Rhine rivers DOWNSTREAM CHANGES OF ALPINE ZIRCON  

E-print Network

Alpine zircon fission-track ages in the Rhône and Rhine rivers DOWNSTREAM CHANGES OF ALPINE ZIRCON FISSION-TRACK AGES IN THE RH�NE AND RHINE RIVERS MATTHIAS BERNET1, 2 , MARK T. BRANDON1 , JOHN I. GARVER3, Bellingham, Washington, 98225, U.S.A. Keywords: detrital, zircon, fission-track, Rhône River, Rhine River

Paris-Sud XI, Université de

319

Sm–Nd systematics of zircon  

Microsoft Academic Search

147Sm–143Nd and 146Sm–142Nd systems were studied in nineteen 3.32–4.02 Ga zircon grains from Jack Hills metaconglomerate, 12 of which were previously analyzed for Lu–Hf. Nd concentrations in the zircons are 0.9–20 ppm.The amount of Nd recovered was between 13 and 446 pg. The analytical precision of 142Nd\\/144Nd and 143Nd\\/144Nd ratios varied between 0.004% and 0.08% (2?m) depending on the sample

Yuri Amelin

2004-01-01

320

Extinct 244Pu in ancient zircons.  

PubMed

We have found evidence, in the form of fissiogenic xenon isotopes, for in situ decay of 244Pu in individual 4.1- to 4.2-billion-year-old zircons from the Jack Hills region of Western Australia. Because of its short half-life, 82 million years, 244Pu was extinct within 600 million years of Earth's formation. Detrital zircons are the only known relics to have survived from this period, and a study of their Pu geochemistry will allow us to date ancient metamorphic events and determine the terrestrial Pu/U ratio for comparison with the solar ratio. PMID:15459384

Turner, Grenville; Harrison, T Mark; Holland, Greg; Mojzsis, Stephen J; Gilmour, Jamie

2004-10-01

321

Subterahertz excitations and magnetoelectric effects in hexaferrite-piezoelectric bilayers  

SciTech Connect

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 (BaAl{sub 2}Fe{sub 10}O{sub 19}) 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 0.37 Oe cm/kV.

Ustinov, Alexey B. [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States); Department of Physical Electronics and Technology, St. Petersburg Electrotechnical University, St. Petersburg 197376 (Russian Federation); Srinivasan, G. [Department of Physics, Oakland University, Rochester, Michigan 48309 (United States)

2008-10-06

322

The effect of biaxial texture on the effective electromechanical constants of polycrystalline barium titanate and lead titanate thin films  

E-print Network

barium titanate and lead titanate thin films Jennifer L. Ruglovsky a,*, Jiangyu Li b , Kaushik to an enhanced piezoelectric effect for barium titanate films, but not for lead titanate. Twist texturing about for a polycrystalline film. We explore tetragonal 4MM materials, and give specific results for barium titanate and lead

Atwater, Harry

323

Computer modelling of barium titanate  

Microsoft Academic Search

Barium titanate is an important material for both scientific and industrial applications. Much of the interest centres around its ferroelectric properties, since it is structurally the most simple in this class. In addition rare-earth doped ceramics are found to exhibit a very steep positive temperature coefficient of resistance (PTCR) above the Curie point. The theory of this PTCR effect is

G. V. Lewis; C. R. A. Catlow

1983-01-01

324

GCM Simulations of Titan's Paleoclimate  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

325

TITAN TECH TALK INFORMATION TECHNOLOGY  

E-print Network

, student course lists and details, TitanCard balances, computer availability in major computer labs a parking spot? View the number of spaces available in real time. 4. PHONE DIRECTORY iFullerton gives you with you some of the projects we've been working on to enhance the educational experience at CSUF such as

de Lijser, Peter

326

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

327

A variable stiffness PZT cellular actuator with tunable resonance for cyclic motion tasks  

E-print Network

A simple and efficient approach for varying the inherent stiffness and impedance of a muscle-like actuator is presented. The basic architecture of PZT cellular actuators has already achieved a large effective strain (10-20%). ...

Secord, Thomas William

328

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

SciTech Connect

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.

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

1999-01-07

329

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

NASA Technical Reports Server (NTRS)

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.

Hooker, Matthew W.

1998-01-01

330

Single mode Lamb wave phased array beamforming with hybrid PZT-SLDV sensing  

NASA Astrophysics Data System (ADS)

This paper presents a single Lamb mode phased array beamforming by using a hybrid piezoelectric transducer (PZT)-scanning laser Doppler vibrometer (SLDV) system. The array system consists of a surface mounted PZT to generate Lamb waves and a non-contact SLDV to acquire high spatial resolution time-space wavefield remotely. The time-space wavefield contains Lamb waves which can be generated from the PZT excitation, damage scattering, mode conversion, etc. A frequency-wavenumber (f-k) decomposition technique is used to decompose the miscellaneous Lamb waves into individual wave mode components and wave propagations in different directions. The f-k decomposition allows using a single wave component as the phased array input for beamforming. The single mode array beamforming methodology was verified through PZT-SLDV experimental tests on an aluminum plate with a bonded quartz rod as a simulated damage

Tian, Zhenhua; Yu, Lingyu

2014-04-01

331

Ti-in-zircon thermometry: applications and limitations  

NASA Astrophysics Data System (ADS)

The titanium concentrations of 484 zircons with U-Pb ages of ˜1 Ma to 4.4 Ga were measured by ion microprobe. Samples come from 45 different igneous rocks (365 zircons), as well as zircon megacrysts (84) from kimberlite, Early Archean detrital zircons (32), and zircon reference materials (3). Samples were chosen to represent a large range of igneous rock compositions. Most of the zircons contain less than 20 ppm Ti. Apparent temperatures for zircon crystallization were calculated using the Ti-in-zircon thermometer (Watson et al. 2006, Contrib Mineral Petrol 151:413-433) without making corrections for reduced oxide activities (e.g., TiO2 or SiO2), or variable pressure. Average apparent Ti-in-zircon temperatures range from 500° to 850°C, and are lower than either zircon saturation temperatures (for granitic rocks) or predicted crystallization temperatures of evolved melts (˜15% melt residue for mafic rocks). Temperatures average: 653 ± 124°C (2 standard deviations, 60 zircons) for felsic to intermediate igneous rocks, 758 ± 111°C (261 zircons) for mafic rocks, and 758 ± 98°C (84 zircons) for mantle megacrysts from kimberlite. Individually, the effects of reduced a_{TiO2} or a_{SiO2}, variable pressure, deviations from Henry’s Law, and subsolidus Ti exchange are insufficient to explain the seemingly low temperatures for zircon crystallization in igneous rocks. MELTs calculations show that mafic magmas can evolve to hydrous melts with significantly lower crystallization temperature for the last 10-15% melt residue than that of the main rock. While some magmatic zircons surely form in such late hydrous melts, low apparent temperatures are found in zircons that are included within phenocrysts or glass showing that those zircons are not from evolved residue melts. Intracrystalline variability in Ti concentration, in excess of analytical precision, is observed for nearly all zircons that were analyzed more than once. However, there is no systematic change in Ti content from core to rim, or correlation with zoning, age, U content, Th/U ratio, or concordance in U-Pb age. Thus, it is likely that other variables, in addition to temperature and a_{TiO2}, are important in controlling the Ti content of zircon. The Ti contents of igneous zircons from different rock types worldwide overlap significantly. However, on a more restricted regional scale, apparent Ti-in-zircon temperatures correlate with whole-rock SiO2 and HfO2 for plutonic rocks of the Sierra Nevada batholith, averaging 750°C at 50 wt.% SiO2 and 600°C at 75 wt.%. Among felsic plutons in the Sierra, peraluminous granites average 610 ± 88°C, while metaluminous rocks average 694 ± 94°C. Detrital zircons from the Jack Hills, Western Australia with ages from 4.4 to 4.0 Ga have apparent temperatures of 717 ± 108°C, which are intermediate between values for felsic rocks and those for mafic rocks. Although some mafic zircons have higher Ti content, values for Early Archean detrital zircons from a proposed granitic provenance are similar to zircons from many mafic rocks, including anorthosites from the Adirondack Mts (709 ± 76°C). Furthermore, the Jack Hills zircon apparent Ti-temperatures are significantly higher than measured values for peraluminous granites (610 ± 88°C). Thus the Ti concentration in detrital zircons and apparent Ti-in-zircon temperatures are not sufficient to independently identify parent melt composition.

Fu, Bin; Page, F. Zeb; Cavosie, Aaron J.; Fournelle, John; Kita, Noriko T.; Lackey, Jade Star; Wilde, Simon A.; Valley, John W.

2008-08-01

332

Dielectric and piezoelectric properties of PNN-PZN-PZT ceramics for actuator application  

Microsoft Academic Search

In the fields of optics, precision machinery and semiconductor processing, microposition actuators are required for the control of position in the submicron range. In this paper, 0.5PNN-(0.5-x)PZN-xPZT(x:0.0~0.5) ceramics were fabricated with various mole ratios of the PZT powders prepared by a molten-salt synthesis method and PNN, PZN powders prepared by a columbite precursor method. The formation rate of perovskite phase

Su-Ho Lee; Han-Geun Kim; Hun-Il Choi; Geon Sa-Gong

1997-01-01

333

A self-excited micro cantilever biosensor actuated by PZT using the mass micro balancing technique  

Microsoft Academic Search

A micro biosensor, which can be applied to a Lab-On-a-Chip (LOC), is developed in order to detect biomaterials such as protein or DNA. The biomaterials are detected by mass micro-balancing technique, which measures the change of the resonant frequency of the sensor structure. The sensor structure consists of a micro cantilever actuated by piezoelectric PZT film. The PZT film is

Yeolho Lee; Geunbae Lim; Wonkyu Moon

2006-01-01

334

Imprint Behavior of Piezoelectric PZT Thin Films Deposited onto Cu-Coated Polymer Substrates  

Microsoft Academic Search

In this work, we investigate the imprint behavior of lead-rich Pb(Zr, Ti)O3 (PZT) thin films deposited onto copper-coated Kapton® substrates by piezoresponse force microscopy. As-deposited films, consisting of a mixture of PZT and lead and zirconium oxides, had a strongly imprinted polarization state with a polarization vector pointing toward the film surface. Above a threshold field of about 10 V\\/?m,

G. Suchaneck; Z. Hubi?ka; M. ?ada; D. A. Kiselev; I. Bdikin; A. A. Levin; L. Jastrabík; A. L. Kholkin; G. Gerlach; A. Dejneka

2011-01-01

335

Dip coating of PT, PZ and PZT films using an alkoxide-diethanolamine method  

Microsoft Academic Search

Dip-coating of uniform PT, PZ and PZT films was investigated using a solution of titanium tetraisopropoxide (and\\/or zirconiumn-butoxide), diethanolamine, lead acetate trihydrate and isopropanol, where the diethanolamine\\/alkoxide molar ratioR = 1 and the water\\/alkoxide molar ratioW = 3. Perovskite-type PT and PZT films were obtained on glass substrates above 500 to 600 ° C when the solutions with concentrations equal

Yasutaka Takahashi; Yoshihiro Matsuoka; Kouichi Yamaguchi; Michiyasu Matsuki; Keisuke Kobayashi

1990-01-01

336

Anhydrous Ammonia Frost on Titan  

NASA Astrophysics Data System (ADS)

Ammonia has been suggested as a probable source for sustaining Titan's thick nitrogen-dominated atmosphere. Ammonia is believed to be important to maintaining nitrogen in Titan's atmosphere. Ammonia is seen in clouds in the atmospheres of Jupiter and Saturn, but has yet to be detected on any of the satellites. This may be because all forms of NH3 are unstable in the ambient conditions of the satellites surfaces or that its spectral features are altered by other components of the surface, and have not been identified. It has recently been demonstrated[1] that brightening occurs in Titan’s atmosphere that is transient on the time-scale of months. The spectral shape of the brightening is more consistent with that of the transient apparition of a pure ammonia frost than of an ammonia monohydrate or ammonia dihydrate frost. However, the phase behavior of the ammonia water system has peritectics at compositions of 1:1 and 1:2. These hydrate forms would be expected to dominate if the frost, or the reservoir from which the frost was derived had any water present. Physical mechanisms for producing measurable quanitities of anhydrous ammonia can include chemical dehydration or dehydration of the vapor phase - but it is challenging to store significant quantities of the anhydrous material because of the phase behavior in the solid state. [1] Nelson, R.M., et al. Saturn’s Titan: Surface Change, Ammonia, and Implications for Atmospheric and Tectonic Activity., Icarus, 199, pp. 429-441, 2009 This work was performed at JPL under contract to NASA

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

2009-12-01

337

Dunes reveal Titan's recent history  

NASA Astrophysics Data System (ADS)

Large fields of linear dunes are abundant on Titan, covering nearly 20% of the surface. They are among the youngest features and represent interactions between near-surface winds and sediment. This interaction may vary from area to area creating unique populations of eolian features identified by dune field parameters such as crest-to-crest spacing, dune width and orientation. These parameters respond to changes in near-surface conditions over periods of time ranging from minutes to many thousands of years depending on dune size and the duration of the changes. While pattern analysis of dune field parameters on Earth and, in this study, Titan reveals much about current climatic conditions, such as wind regimes and wetter vs. drier areas, many inferences about past conditions can also be made. Initial pattern analysis of linear dunes on Titan reveals a single population of linear dunes representing a large percentage of all observed dunes. This single population is the result of two leading possibilities: Either there has been only one long period of dune building, leading to very old cores that have been built upon over long periods of time, perhaps punctuated with few or many intervals of non-deposition; or the current conditions of dune building have persisted long enough to completely erase any evidence of previous conditions. We have not yet worked through all the input parameters to adjust Earth's time scales to Titan's, and thus it is not yet possible to give a precise age for Titan's dunes. However, if these large linear dunes are similar to Earth's large linear dunes, they may represent at least several thousand years of dune building.

Savage, Christopher J.; Radebaugh, Jani

2010-04-01

338

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

339

Numerical analysis of PZT rebar active sensing system for structural health monitoring of RC structure  

NASA Astrophysics Data System (ADS)

An active sensing diagnostic system for reinforced concrete SHM has been under investigation. Test results show that the system can detect the damage of the structure. To fundamentally understand the damage algorithm and therefore to establish a robust diagnostic method, accurate Finite Element Analysis (FEA) for the system becomes essential. For the system, a rebar with surface bonded PZT under a transient wave load was simulated and analyzed using commercial FEA software. A detailed 2D axi-symmetric model for a rebar attaching PZT was first established. The model simulates the rebar with wedges, an epoxy adhesive layer, as well as a PZT layer. PZT material parameter transformation with high order tensors was discussed due to the format differences between IEEE Standard and ANSYS. The selection of material properties such as Raleigh damping coefficients was discussed. The direct coupled-field analysis type was selected during simulation. The results from simulation matched well with the experimental data. Further simulation for debonding damage detection for concrete beam with the PZT rebar has been performed. And the numerical results have been validated with test results too. The good consistency between two proves that the numerical models were reasonably accurate. Further system optimization has been performed based on these models. By changing PZT layout and size, the output signals could be increased with magnitudes. And the damage detection signals have been found to be increased exponentially with the debonding size of the rebar.

Wu, F.; Yi, J.; Li, W. J.

2014-03-01

340

Hubble Observes Surface of Titan  

NASA Technical Reports Server (NTRS)

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

1994-01-01

341

Influence of Composition and Dopant on Photostriction in Lanthanum-Modified Lead Zirconate Titanate Ceramics  

Microsoft Academic Search

The anomalous photovoltaic effect, i.e., substantial voltage generation exceeding band gap energies, by homogeneous illumination in the non-centrosymmetric materials is a wellknown phenomenon. This mechanism is fundamentally different from those observed in heterojunctions\\/homojunctions (i.e., solar cells) based on semiconductor materials with a symmetric crystal structure. Recently, light induced strain termed as Photostriction, has been demonstrated in noncentrosymmetric perovskite ferroelectrics as

P. Poosanaas; K. Tonooka; I. R. Abothu; S. Komarneni; K. Uchino

1999-01-01

342

Electrodynamic properties of lead Zirconate-Titanate thin films in the terahertz frequency range  

NASA Astrophysics Data System (ADS)

The transmission/reflection spectra of bilayer structures consisting of thin amorphous and polycrystalline Pb(Zr0.52Ti0.48)O3 ferroelectric films deposited on dielectric substrates of magnesium oxide MgO and sapphire ?-Al2O3 were measured in the frequency range of 5-4000 cm-1. Based on these spectra and using the dispersion analysis method, the spectra of complex dielectric permittivity ?*(?) and dynamic conductivity ?'(?) of the films were simulated, the electrodynamic parameters of the films were determined, and the dielectric dispersion responsible for the formation of static permittivity was found.

Komandin, G. A.; Porodinkov, O. E.; Iskhakova, L. D.; Spektor, I. E.; Volkov, A. A.; Vorotilov, K. A.; Seregin, D. S.; Sigov, A. S.

2014-11-01

343

Millimeter-wave magnetoelectric effects in bilayers of barium hexaferrite and lead zirconate titanate  

E-print Network

shift f = AE = H in magnetic excitations and comparison with theory. Studies were performed on bilayers to the bilayer plane and parallel to the magnetic easy axis of BaM. A vector network analyzer Agilent-PNA-E8361A

Srinivasan, Gopalan

344

Single crystal study of competing rhombohedral and monoclinic order in lead zirconate titanate.  

PubMed

Neutron diffraction data obtained on single crystals of PbZr(1-x)Ti(x)O3 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. PMID:21231265

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

2010-11-12

345

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

SciTech Connect

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.

Shvartsman, V.V.; Kholkin, A.L.; Orlova, A.; Kiselev, D.; Bogomolov, A.A.; Sternberg, A. [Department of Ceramics and Glass Engineering and Center for Research in Ceramic and Composite Materials (CICECO), University of Aveiro, 3810-193 Aveiro (Portugal); Department of Physics, Tver State University, 170000 Tver (Russian Federation); Institute of Solid State Physics, University of Latvia, LV-1063 Riga (Latvia)

2005-05-16

346

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

E-print Network

Ferroelectric ceramics have been employed extensively in a variety of sensors and actuators including strain of ferroelectric thin films include micro actuators,1 micro sensors,2 ultrasonic motors,3 non- volatile computer was carried out to evaluate the existing methods for determination of the d33 coefficient of ferroelectric

Sottos, Nancy R.

347

Structural and impedance spectroscopic studies of samarium modified lead zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

The polycrystalline samples of Pb 1-xSm x(Zr 0.60Ti 0.40) 1-x/4O 3 (PSZT) where x=0.00, 0.03, 0.06 and 0.09 were prepared by a high-temperature solid-state reaction technique. The preliminary structural analysis using X-ray diffraction (XRD) data collected at room temperature has confirmed the formation of single-phase compounds in tetragonal crystal system. The morphological study of each sample using scanning electron microscope (SEM) has revealed that the grains are uniformly distributed through out the surfaces of the samples. Using complex impedance spectroscopy (CIS) technique, the electrical impedance and modulus properties of the materials were studied in a wide range of temperatures at different frequencies. The impedance analysis indicates the presence of bulk resistive contributions in the materials which is found to decrease on increasing temperature. The nature of variation of resistances with temperature suggests a typical negative temperature coefficient of resistance (NTCR) type behavior of the materials. The complex modulus plots clearly exhibits the presence of grain boundaries along with the bulk contributions in the PSZT materials. The presence of non-Debye type of relaxation has been confirmed by the complex impedance analysis. The variation of dc conductivity (bulk) with temperature demonstrates that the compounds exhibit Arrhenius type of electrical conductivity.

Ranjan, Rajiv; Kumar, Rajiv; Behera, Banarji; Choudhary, R. N. P.

2009-11-01

348

PROPERTIES OF PIEZOELECTRIC TITANATES AND ZIRCONATES INCLUDING A DISCUSSION OF THEIR CONTROL AND EVALUATION  

Microsoft Academic Search

Presented at the 1956 Electronic Components Conf., Washington, D. C., ; May 1956. This paper is in two parts. The flrst part reports on the program ; pursued by Sandia Corporation in a planned effort toward obtaining more uniform ; and efficient piezoelectric ceramics. The second part discasses speciflcations ; and tests used by Sandia to ensure procurement of satisfactory

T. G. Kinsley; R. D. Wehrle

1956-01-01

349

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

DOEpatents

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.

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

1999-06-01

350

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

DOEpatents

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.

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

1999-01-01

351

journal homepage: www.elsevier.com/locate/nanoenergy Available online at www.sciencedirect.com  

E-print Network

of Nanoscience and Nano- technology, Lanzhou University, Lanzhou 730000, China. nn CoQ2 rresponding author at.sciencedirect.com RAPID COMMUNICATION Single crystalline lead zirconate titanate (PZT) nano/micro-wire based self and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA Received 24 August 2012; accepted 5

Wang, Zhong L.

352

Micropatterning and crystallization of sol-gel-derived dielectric film by laser direct writing  

Microsoft Academic Search

Low temperature crystallization and the micropatterning of lead zirconate titanate (PZT) film were achieved by laser direct writing method using a sol-gel derived precursor film. After scanning of an Ar ion laser beam through an objective lens, the etching of the unirradiated area of the precursor film with an acidic solution gave micropatterns with a resolution of several mum. The

Akira Watanabe; Tomokazu Tanase; Kenji Miyajima; Yoshio Kobayashi; Mikio Konno

2010-01-01

353

Large Effective-Strain Piezoelectric Actuators Using Nested Cellular Architecture With Exponential Strain Amplification Mechanisms  

Microsoft Academic Search

Design and analysis of piezoelectric actuators having over 20% effective strain using an exponential strain amplification mechanism are presented in this paper. Piezoelectric ceramic material, such as lead zirconate titanate (PZT), has large stress and bandwidth, but its extremely small strain, i.e., only 0.1%, has been a major bottleneck for broad applications. This paper presents a new strain amplification design,

Jun Ueda; Thomas W. Secord; H. Harry Asada

2010-01-01

354

1058 IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 14, NO. 6, NOVEMBER 2006 Construction and Experimental Implementation of a  

E-print Network

input fields, charge- or current-controlled amplifiers, or feedback designs. For general operating materials, including the compound lead zirconate titanate (PZT), exhibit novel actuator and sensor, piezoelectric transducers are moderately inexpensive and can be designed to minimally affect the passive

Salapaka, Murti V.

355

Construction and Experimental Implementation of a Model-Based Inverse Filter to Attenuate Hysteresis  

E-print Network

fields, charge- or current-controlled amplifiers, or feed- back designs. For general operating conditions the compound lead zirconate titanate (PZT), exhibit novel actuator and sensor capabilities due to the unique transduction and nanometer-level set point accuracy. Furthermore, piezoelectric transducers are moderately

356

Design and simulation of an implantable medical drug delivery system using microelectromechanical systems technology  

Microsoft Academic Search

A unique design of an implantable micropump for medical drug delivery systems was proposed. The peristaltic pumping principle was selected. Three pump chambers are individually actuated by each bulk PZT (lead zirconate titanate) disk in a peristaltic motion. It is this peristaltic motion that propels the fluid. The design of the micropump includes inlet, three pump chambers, three silicon membranes,

Li Cao; Susan Mantell; Dennis Polla

2001-01-01

357

Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage  

Microsoft Academic Search

In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum

Bharat Bhushan; Manuel Palacio; Kwang Joo Kwak

2008-01-01

358

Design and fabrication of a flexible large area fabric transducer for bone healing application  

Microsoft Academic Search

The electromechanical transducers have found applications in their either passive or active modes. These applications include hydrophone, medical imaging, nondestructive evaluation, motors, sensors, actuators, civil and aerospace engineering. Other medical applications for ultrasonic transducers include therapeutics, osteosynthesis, lithotripsy, thrombolysis, and transdermal drug administration. During the past few decades, lead zirconate titanate (PZT), has been utilized in transducer applications in the

Bahram Jadidian

1998-01-01

359

Testing of new ferroelectric elements custom engineered for explosively driven ferroelectric applications  

Microsoft Academic Search

Explosively driven ferroelectric generators (FEGs) are reliable, compact, high voltage sources that utilize high pressures to liberate charge trapped in the crystal structure of ferroelectric materials. For the active ferroelectric element most FEG designs use commercial lead zirconate-titanate (PZT) compositions designed for either precision actuators or naval sonar transducers. However, the material properties that are important in FEG applications are

S. L. Holt; J. T. Krile; D. J. Hemmert; W. S. Hackenberger; E. F. Alberta; J. W. Walter; J. C. Dickens; L. L. Altgilbers; A. H. Stults

2007-01-01

360

Piezoelectric response of single-crystal PbZr1xTixO3 near morphotropic phase boundary predicted by phase-field simulation  

E-print Network

zirconate-titanate PbZr1-xTixO3 PZT ceramic is the most widely studied and utilized ferroelectric piezo- electric system in multilayer actuators, sonar and ultrasonic transducers, ultrasonic motors-temperature ferroelectric phases in the temperature-composition phase diagram. Re- cently it was discovered that relaxor

Chen, Long-Qing

361

MONOLITHICALLY INTEGRATED PIEZOMEMS SP2T SWITCH AND CONTOUR-MODE FILTERS  

E-print Network

tunability. This research leverages previous work using PZT actuators for low-voltage, wide-band switches. Piezoelectric and or ferroelectric transduction can provide superior electro-mechanical coupling and mechanical to its favorable ratio of stress constant to dielectric constant. Ferroelectric lead zirconate titanate

Afshari, Ehsan

362

Testing of New Ferroelectric Elements Custom Engineered for Explosively Driven Ferroelectric Generator Applications  

Microsoft Academic Search

Summary form only given. Explosively driven ferroelectric generators (FEGs) are reliable, compact, high voltage sources that utilize high pressures to liberate charge trapped in the crystal structure of ferroelectric materials. For the active ferroelectric element most FEG designs use commercial lead zirconate-titanate (PZT) compositions designed for either precision actuators or naval sonar transducers. However, the material properties that are important

S. L. Holt; J. T. Krile; D. J. Hemmert; W. S. Hackenberger; E. F. Alberta; J. W. Walter; J. C. Dickens; L. L. Altgilbers; A. H. Stults

2007-01-01

363

Additive deposition and patterning of ferroelectric materials on non-planar surfaces by chemical-solution methods  

Microsoft Academic Search

Recent developments and understanding for the deposition and patterning of ferroelectric thin layers are reported. Two patterning techniques are described for mediated chemical solution deposition by: (i) microcontact printing (?-CP), and (ii) micromolding in capillaries (MIMIC). These additive soft-lithographic methods are demonstrated for the patterning of sol-gel derived lead zirconate titanate (PZT) films on non-planar surfaces

E. A. Mikalsen; D. A. Payne

2000-01-01

364

Ferroelectric Materials for Electromechanical Transducer Applications  

Microsoft Academic Search

Many advantages of ferroelectric compositions in the lead zirconate:lead titanate (PZT) solid solutions for both sensing and actuation are explored. The state of understanding of both intrinsic single domain and extrinsic domain wall and phase boundary contribution to response is described, and the composition manipulations used to modifiy the extrinsic responses explored. In lead magnesium niobate (PMN) based solid solution

Leslie Eric Cross

1995-01-01

365

Determination of critical and minimum volume fraction for composite sensors and actuators  

Microsoft Academic Search

Composite actuators and sensors manufactured by combining a ferroelectric ceramic such as lead zirconate titanate (PZT) and a passive phase such as a polymer are used in a variety of applications including SONAR, vibration damping, change of structural shape (morphing) and structural health monitoring. The composite route provides specific advantages, including tailored piezoelectric response, high strain, a degree of flexibility

C. R. Bowen; A. C. Dent; R. Stevens; M. Cain; M. Stewart

366

Performance of integrated active fiber composites in fiber reinforced epoxy laminates  

Microsoft Academic Search

Active fiber composite (AFC) composed of lead zirconate titanate (PZT) fibers with interdigitated electrodes (IDEs) has been integrated into orthotropic glass fiber reinforced plastic (GFRP) laminates to characterize the performance of AFC as a smart material component in laminated materials. Monotonic cyclic tensile loading was performed on integrated specimens at different strain levels. The AFC output was monitored to determine

M. Melnykowycz; X. Kornmann; C. Huber; M. Barbezat; A. J. Brunner

2006-01-01

367

Application of a Classical Lamination Theory Model to the Design of Piezoelectric Composite Unimorph Actuators  

Microsoft Academic Search

This work presents the design, development, and characterization of unimorphtype laminated piezoelectric actuators. The actuators consist of a piezoelectric lead zirconate titanate (PZT) layer sandwiched between unidirectional Kevlar 49 and epoxy composite layers. Differential thermal expansion during processing places the ceramic plate in a state of residual compression and results in a curved actuator. Modified classical lamination theory (MCLT) (modified

Kyle G. Webber; David P. Hopkinson; Christopher S. Lynch

2006-01-01

368

Fabrication and characterization of transducer elements in two-dimensional arrays for medical ultrasound imaging  

Microsoft Academic Search

Some of the problems of developing a two-dimensional (2-D) transducer array for medical imaging are examined. The fabrication of a 2-D array material consisting of lead zirconate titanate (PZT) elements separated by epoxy is discussed. Ultrasound pulses and transmitted radiation patterns from individual elements in the arrays are measured. A diffraction theory for the continuous wave pressure field of a

Daniel H. Turnbull; F. S. Foster

1992-01-01

369

Fabrication of a gas flow device consisting of micro-jet pump and flow sensor  

Microsoft Academic Search

A gas-flow device consisting of a valveless micro jet pump and flow sensor has been designed and fabricated using a Si micromachining process. The valveless micro pump is composed of a piezoelectric lead zirconate titanate (PZT) diaphragm actuator and flow channels. The design of the valvless pump focuses on a crosss junction formed by the neck of the pump chamber

Katsuhiko Tanaka; Van T. Dau; Tomonori Otake; Thien X. Dinh; Susumu Sugiyama

2008-01-01

370

Amino acidis derived from Titan tholins  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

371

The Global Energy Balance of Titan  

NASA Technical Reports Server (NTRS)

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%.

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

372

Pluto's implications for a Snowball Titan  

NASA Astrophysics Data System (ADS)

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.

Wong, Michael L.; Yung, Yuk L.; Randall Gladstone, G.

2015-01-01

373

Cassini Imaging Observations of Titan  

Microsoft Academic Search

The Cassini ISS team will present preliminary results from new high-resolution images of Titan. ISS can best detect the surface and lower-troposphere clouds though a narrow filter centered in the 940-nm methane window. Near-global coverage acquired during approach to Saturn revealed 100-km-scale dark markings in the equatorial region, some with straight trends or boundaries suggestive of tectonic influences. Cassini passed

A. McEwen; E. Turtle; J. Perry; T. Johnson; A. Del Genio; D. Dawson; S. Campbell; J. Barbara; C. Porco

2004-01-01

374

PZT Network and Phased Array Lamb Wave Based SHM Systems  

NASA Astrophysics Data System (ADS)

With the application of newer materials, such as composite materials, and growing complexity and capacity of current aircraft structures, reliably and completely assess the condition of the total structures in real time is then of growing and utmost importance. PZT Network and Phased Array, Lamb wave based Structural Health Monitoring (SHM) systems were developed to be applied to thin panels. The selection of transducers, their size and selected locations for their installation are described. The development and selection of the signal generation and data acquisition systems is also presented in detail. The requirements conducing to the development and selection of these systems are laid and particularly the selection of the actuation signal applied is justified. The development of a damage detection algorithm based in the comparison of the current structural state to a reference state is described, to detect damage reflected Lamb waves. Such method was implemented in software and integrated in the SHM system developed. Subsequently the detection algorithm, based in discrete signals correlation, was further improved by incorporating statistical methods. For phased arrays, a novel damage location algorithm is presented based on the individual sensors response. A visualization method based concurrently in the statistical methods developed and superposition of the different results obtained from a test set was implemented. These tests conducted to the successful and repeatable detection of 1mm damages in a multiple damaged plate with great confidence. Finally, a brief comparison and a hybrid system implementation is presented.

Silva, C.; Rocha, B.; Suleman, A.

2011-07-01

375

Octahedral tilting, monoclinic phase and the phase diagram of PZT  

NASA Astrophysics Data System (ADS)

Anelastic and dielectric spectroscopy measurements on PbZr1-xTixO3 (PZT) close to the morphotropic (MPB) and antiferroelectric boundaries provide new insight into some controversial aspects of its phase diagram. No evidence is found of a border separating monoclinic (M) from rhombohedral (R) phases, in agreement with recent structural studies supporting a coexistence of the two phases over a broad composition range x < 0.5, with the fraction of M increasing toward the MPB. It is also discussed why the observed maximum of elastic compliance appears to be due to a rotational instability of the polarization linearly coupled to shear strain. Therefore it cannot be explained by extrinsic softening from finely twinned R phase alone, but indicates the presence also of M phase, not necessarily homogeneous. A new diffuse transition is found within the ferroelectric phase near x ˜ 0.1, at a temperature TIT higher than the well established boundary TT to the phase with tilted octahedra. It is proposed that around TIT the octahedra start rotating in a disordered manner and finally become ordered below TT. In this interpretation, the onset temperature for octahedral tilting monotonically increases up to the antiferroelectric transition of PbZrO3, and the depression of TT(x) below x = 0.18 would be a consequence of the partial relief of the mismatch between the average cation radii with the initial stage of tilting below TIT.

Cordero, F.; Trequattrini, F.; Craciun, F.; Galassi, C.

2011-10-01

376

Measurement and calculation of PZT thin film longitudinal piezoelectric coefficients.  

SciTech Connect

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.

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

1999-04-26

377

Electromechanical constitutive behavior of various compositions of PZT and PLZT  

NASA Astrophysics Data System (ADS)

A critical step in the design and development of large strain ceramic actuators is the choice of material and composition. The number of available materials is rapidly growing. It now includes the range of soft to hard PZTs, relaxor ferroelectric PLZT and PMN.PT, and electric field induced phase transformation materials PLSnZT. The development of new materials is leading to ever larger strain, but there is a catch that device designers should be aware of. In some systems increased strain is achieved by developing compositions near thermodynamically metastable states, resulting in temperature, stress, and frequency dependence of the strain/electric-field coupling. This work examines the behavior of several compositions of PZT and 8/65/35 PLZT under combined stress and electric field. Additional data is available for a relaxor ferroelectric composition 8/65/35 PLZT (Lynch 1993, 1994). The results show that the addition of dopants to increase hardness reduces the piezoelectric coefficients, but it also increases both the electrical and mechanical yield points. This allows operation over a broader electric field and stress range with less internal heating due to dielectric loss. The materials that produce the largest strain and the least hysteresis in the presence of compressive stress are not necessarily those with the largest piezoelectric d333 coefficients.

Lynch, Christopher S.

1995-05-01

378

Safe prescribing: a titanic challenge  

PubMed Central

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

Routledge, Philip A

2012-01-01

379

Atomistic simulation of collision cascades in zircon  

NASA Astrophysics Data System (ADS)

Defect production in energetic collision cascades in zircon has been studied by molecular dynamics simulation using a partial charge model combined with the Ziegler-Biersack-Littmark potential. Energy dissipation, defect accumulation, Si-O-Si polymerization and Zr coordination number were examined for 10 keV and 30 keV U recoils simulated in the constant NVE ensemble. For both energies an amorphous core was produced with features similar to that of melt quenched zircon. Disordered Si ions in this core were polymerized with an average degree of polymerization of 1.5, while disordered Zr ions showed a coordination number of about 6 in agreement with EXAFS results. These results suggest that nano-scale phase separation into silica- and zirconia-rich regions occurs in the amorphous core.

Devanathan, R.; Corrales, L. R.; Weber, W. J.; Chartier, A.; Meis, C.

2006-09-01

380

The crystallization age of eucrite zircon.  

PubMed

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

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

2007-07-20

381

Zircon megacrysts from kimberlite: oxygen isotope variability among mantle melts  

Microsoft Academic Search

The oxygen isotope ratios of Phanerozoic zircons from kimberlite pipes in the Kaapvaal Craton of southern Africa and the\\u000a Siberian Platform vary from 4.7 to 5.9‰ VSMOW. High precision, accurate analyses by laser reveal subtle pipe-to-pipe differences\\u000a not previously suspected. These zircons have distinctive chemical and physical characteristics identifying them as mantle-derived\\u000a megacrysts similar to zircons found associated with diamond,

John W. Valley; Peter D. Kinny; Daniel J. Schulze; Michael J. Spicuzza

1998-01-01

382

Extinct Plutonium Geochemistry of Ancient Hadean Zircons  

Microsoft Academic Search

The abundance of 244Pu in the early solar system has important implications for r-process nucleosynthesis and models of noble gas transport within the Earth's mantle. Our recent discovery(1) of xenon isotopes from the in-situ decay of 244Pu in ancient Jack Hills zircons promises to provide a new time-sensitive window on the first 500 Ma of Earth history. We have extended

G. Turner; J. Gilmour; S. Crowther; A. Busfield; S. Mojzsis; M. Harrison

2005-01-01

383

Dissolution of PZT 52/48 in aqueous sulfuric acid environments  

NASA Astrophysics Data System (ADS)

With the recent interest for PZT use as a self-powered nanonsensor in extreme environments, such as an oil well, it is important to ensure the stability of the material under these conditions. Oil wells are known for being extremely caustic, with high temperature, low pH and high pressures. It has been shown that in the presence of sulfuric acid PZT is subject to chemical attack. This study attempts to identify the effects that pH and temperature have on the rate of the reaction. Sulfuric acid was used as a proxy for the H2S environment found in oil wells. Exposure of bulk PZT and thin film specimens to H2S was studied. PZT 52/48 thin films were fabricated via the sol gel process. PZT was exposed to both single drops of aqueous sulfuric acid and submerged in a bath of solution. During bath exposure potential on the substrate surface of thin film samples was recorded using a voltmeter vs. and Ag/AgCl reference electrode. Thin Film samples were exposed to a single drop of 0.1 N and 1 N aqueous sulfuric acid solutions at temperatures between 25° C and 92° C. It was optically observed that a white filmed appeared on the surface as a reaction product. At both concentrations, increases in temperature lead to an increase in reaction rate for droplet exposed samples. These reactions were found to follow Arrhenius behavior. The 1 N solution activation energy of film appearance was found to be 69100 J, and for 0.1 N solution was found to be 48300 J. It was expected that an increase in concentration would lead to an increase in reaction rate as well. However for single droplet exposure it was found that lower concentrations resulted in increased reaction rate. This may be due to the difference in interfacial energy between the solution and PZT surface as a result of the concentration of sulfuric acid. The potential on the substrate during bath exposure was between -0.22 V and 0.1 V. As a ferroelectric, PZT is expected to spontaneously polarize and variations in potential are expected. The value of -0.22 V corresponds to the potential of a normal hydrogen electrode, the conditions that would be found if the platinum layer were exposed, which could occur due to pinholes in the sample. The potential on the substrate and time of exposure were not found to correspond to dissolution depth using XPS depth profiling. A proposed reason is that attack was not found to be uniform across the surface, most likely as a result of high energy regions such as pinholes in the PZT film. Using XPS and XRD characterization techniques, PbSO4 was found to be one reaction product of both the PZT bulk sample exposed to a bath of solution, and thin film samples exposed to a single droplet of solution. Other reaction products were not able to be identified using the analysis techniques in this study, because the reaction products of zirconium and titanium are believed to take the form of ions in solution. While XPS confirmed their elemental presence in solution after evaporation, analysis of the solution itself was never conducted. Suggested future work and analytical techniques are also proposed to fully characterize the dissolution kinetics of PZT in aqueous sulfuric acid. These include the characterization of the interfacial energy between solution droplets and PZT surface, potentiostatic bath exposure of thin films in which the potential on the substrate is fixed, solution analysis via ICP-MS or other alternative, and the comparison of dissolution rate between bulk PZT and thin film PZT to determine the effect pinholes may have on the reaction. Various temperatures and acid concentrations are also proposed in order to fully characterize the Arrhenius behavior of reaction rate.

Calebrese, Steven

384

The surface age of Titan  

NASA Astrophysics Data System (ADS)

So far five impact craters have been confirmed on Titan's surface and 42 possible impact-like features have been identified [1-9]. In general, they are circular and appear to have elevated rims and interiors. Many of the larger of these features show evidence of having been significantly eroded. Others are partially or nearly completely covered by dunes, fluvial channels have cut a few, and many are surrounded by talus. As on Earth there are multiple processes on Titan that can erode craters and significantly alter their appearance. The overall shape of the frequency distribution of both, the confirmed and putative ones, is relatively flat compared to those of other icy satellites, especially at smaller crater diameters. However, the cumulative crater frequency for larger diameters remarkably fits that of the basins on Iapetus for craters down to about 80 km diameter, although the number of craters is lower by about an order of magnitude. The crater frequency at sizes < 80 km is far lower by about a factor of up to 200. Compared to the crater frequency distribution on Earth, Titan shows a similar shape, however, the density is about 5 to 10 times higher. The absolute age models according to [10,11] assumes a lunar-like impactor flux mainly of main-belt asteroids, whereas [12,13] assume a constant impactor flux of cometary objects, either with a size distribution of Jupiter family comets (JFC) (case A), or with a size distribution of small comets in the Neptunian System (case B). According to the [10,11]-age model Titan's surface is as old as 3.9 Ga as derived from the larger-crater (> 80 km) frequencies. The [12,13]-age model yields surface ages of 3.5 Ga in case A and 1.4 Ga in case B. If only smaller craters, e.g. 10 km-sized craters, are taken into account for age determination, surface ages are 100 Ma according to the [10,11]-age model, 8 Ma according to [12,13]-age model case A, and 2 Ma for case B. Although the statistical precision of the Titan cratering results is not very high and cratering models for absolute ages are controversial, it is obvious that Titan's surface is partly as old as the other Saturnian satellites reflecting an early crust, still preserved, and has been partly modified and heavily resurfaced even in recent times. References: [1] Porco, C.C. et al., (2005) Nature, 434, 159-168. [2] Elachi, C. et al., (2005) Science, 308, 970-974. [3] Wood C.A., et al., (2006), LPSC XXXVII,#1659. [4] Lorenz R., et al., (2007), Geophys. Res. Lett., 34. [5] Jaumann R., et al., (2009), in Titan after Cassini-Huygens (R.H. Brown et al. (eds)), Springer, London, subm.. [6] Perry et., Sat. of the Outer Solar System, #6064. [7] Lorenz, R.D. et. Al., Sat. of the Outer Solar System, #6012. [8] Soderblom, L., et al., PSS 44, 2035-2036. [9] Rodrigues, S., et al., PSS 54, 1510-1523. [10] Neukum, G., (1985), Adv. Space Res. 5, 107-116. [11] Neukum, G., et al., (2005), Lunar Planet. Sci. Conf. 36th, abstract 2034. [12] Zahnle, K., et al., (2003), Icarus 163, 263-289. [13] Korycansky, D.G., and Zahnle, K.J., (2005), Planet. Space Sci. 52, 695-710.

Jaumann, R.; Neukum, G.

2009-04-01

385

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios.  

PubMed

The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 ?m in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P(r), and transverse piezoelectric coefficient, e(31,) (f), increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 ?C/cm(2), a dielectric constant of 450 (at 1 kHz), and e(31,) (f) = -2.8 C/m(2). Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 ?C/cm(2), a dielectric constant of 1250 (at 1 kHz) and e(31,) (f) = -5.8 C/m(2). PMID:20376196

Wu, Dawei; Zhou, Qifa; Shung, Koping Kirk; Bharadwaja, Srowthi N; Zhang, Dongshe; Zheng, Haixing

2009-05-01

386

Ferroelectric properties of PZT/BFO multilayer thin films prepared using the sol-gel method.  

PubMed

In this study, Pb(Zr0.52Ti0.48)O3/BiFeO3 [PZT/BFO] multilayer thin films were fabricated using the spin-coating method on a Pt(200 nm)/Ti(10 nm)/SiO2(100 nm)/p-Si(100) substrate alternately using BFO and PZT metal alkoxide solutions. The coating-and-heating procedure was repeated several times to form the multilayer thin films. All PZT/BFO multilayer thin films show a void-free, uniform grain structure without the presence of rosette structures. The relative dielectric constant and dielectric loss of the six-coated PZT/BFO [PZT/BFO-6] thin film were approximately 405 and 0.03%, respectively. As the number of coatings increased, the remanent polarization and coercive field increased. The values for the BFO-6 multilayer thin film were 41.3 C/cm2 and 15.1 MV/cm, respectively. The leakage current density of the BFO-6 multilayer thin film at 5 V was 2.52 × 10-7 A/cm2. PMID:22221519

Jo, Seo-Hyeon; Lee, Sung-Gap; Lee, Young-Hie

2012-01-01

387

Role of zircon in tracing crustal growth and recycling  

NASA Technical Reports Server (NTRS)

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.

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

388

Titania bound sodium titanate ion exchanger  

DOEpatents

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.

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

389

Titan aerover all-terrain vehicle  

NASA Astrophysics Data System (ADS)

A preliminary design for a Titan mobility system is a modified blimp that can operate in Titan's thick, cold atmosphere as well as drive on its solid surfaces and anticipated liquid hydrocarbon oceans. Testing with models has begun and technology focus areas have been identified as materials, control, navigation, deployment, and power. .

Jones, Jack A.; Lorenz, Ralph D.

2002-01-01

390

Die Absorptionsspektren von Vanadium, Titan und Scandium  

Microsoft Academic Search

Zusammenfassung Unter Benutzung eines elektrischen Ofens nach dem Muster der Öfen von A. King werden die Absorptionslinien der Dämpfe von Vanadium, Titan und Scandium bei 20000 C ermittelt. Die quantentheoretische Deutung dieser Ergebnisse gelingt unter Benutzung der bisher bekannten Gesetzmäßigkeiten in den Bogenspektren dieser Elemente, die einer kritischen Durchsicht unterzogen und insbesondere bei Titan durch Angabe neuer Multipletts vervollständigt werden.

H. Gieseler; W. Grotrian

1924-01-01

391

The tide in the seas of Titan  

Microsoft Academic Search

The parameters of the tides in the near-global ocean that may exist on Titan are assessed. A formula for the difference between the maximum heights of the oceanic and body tides is used to determine that the amplitude of the apparent, near-stationary, oceanic tide on Titan is greater than about 100 m. The effects of tidal dissipation are evaluated, showing

Carl Sagan; S. F. Dermott

1982-01-01

392

Detection of Daily Clouds on Titan  

Microsoft Academic Search

We have discovered frequent variations in the near-infrared spectrum of Titan, Saturn's largest moon, which are indicative of the daily presence of sparse clouds covering less than 1% of the area of the satellite. The thermodynamics of Titan's atmosphere and the clouds' altitudes suggest that convection governs their evolutions. Their short lives point to the presence of rain. We propose

Caitlin A. Griffith; Joseph L. Hall; Thomas R. Geballe

2000-01-01

393

Photochemically Driven Collapse of Titan's Atmosphere  

E-print Network

(1) because of the competing influences of a strong green- house effect (2) dominated time of 2 million years (11)]. Despite its low abundance, H2 is an important green- house gas models of Titan's atmosphere show that methane depletion may have al- lowed Titan's atmosphere to cool so

Lorenz, Ralph D.

394

Titan/Cassini: lifting module into stand  

NASA Technical Reports Server (NTRS)

The Lower Equipment Module of the Cassini spacecraft is lifted into a workstand in the Payload Hazardous Servicing Facility (PHSF). Cassini will explore the Saturnian system, including the planet's rings and its moon, Titan. Launch of the Cassini mission to Saturn is scheduled for Oct. 6 from Launch Complex 40, Cape Canaveral Air Station, aboard a Titan IVB unmanned vehicle.

1997-01-01

395

Nitrogen loss from Titan V. I. Shematovich  

E-print Network

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

Johnson, Robert E.

396

Techniques for the In Situ Analysis of Titan Lake Fluids  

NASA Astrophysics Data System (ADS)

Titan’s lakes are a primary target for future Titan exploration. We present two successfully tested in situ methods to analyze Titan lake fluids: 1) fiber optic probes, and 2) solid phase micro-extraction (SPME) fibers for preconcentration of analytes.

Hodyss, R.; Malaska, M. J.; Beauchamp, P. M.

2014-02-01

397

DIMENSIONLESS BANKFULL HYDRAULIC RELATIONS FOR EARTH AND TITAN  

E-print Network

surface is likely active in modern geological time! Tectonic ridges? #12;7 MARS VERSUS TITAN contd time! #12;10 MARS VERSUS TITAN contd. Impact crater Titan shows evidence of active tectonics, vulcanism to the internet! I had waited for years! #12;4 MARS VERSUS TITAN Mars shows evidence of ancient rivers of flowing

Parker, Gary

398

Size and shape of Saturn's moon Titan.  

PubMed

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

Zebker, Howard A; Stiles, Bryan; Hensley, Scott; Lorenz, Ralph; Kirk, Randolph L; Lunine, Jonathan

2009-05-15

399

Size and shape of Saturn's moon Titan  

USGS Publications Warehouse

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.

Zebker, Howard A.; Stiles, Bryan; Hensley, Scott; Lorenz, Ralph; Kirk, Randolph L.; Lunine, Jonathan

2009-01-01

400

Growth mechanisms and dune orientation on Titan  

NASA Astrophysics Data System (ADS)

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.

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

401

Interaction of Titan's ionosphere with Saturn's magnetosphere.  

PubMed

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

Coates, Andrew J

2009-02-28

402

Octahedral tilting, monoclinic phase and the phase diagram of PZT.  

PubMed

Anelastic and dielectric spectroscopy measurements on PbZr(1-x)Ti(x)O(3) (PZT) close to the morphotropic (MPB) and antiferroelectric boundaries provide new insight into some controversial aspects of its phase diagram. No evidence is found of a border separating monoclinic (M) from rhombohedral (R) phases, in agreement with recent structural studies supporting a coexistence of the two phases over a broad composition range x<0.5, with the fraction of M increasing toward the MPB. It is also discussed why the observed maximum of elastic compliance appears to be due to a rotational instability of the polarization linearly coupled to shear strain. Therefore it cannot be explained by extrinsic softening from finely twinned R phase alone, but indicates the presence also of M phase, not necessarily homogeneous.A new diffuse transition is found within the ferroelectric phase near x ~ 0.1, at a temperature T(IT) higher than the well established boundary T(T) to the phase with tilted octahedra. It is proposed that around T(IT) the octahedra start rotating in a disordered manner and finally become ordered below T(T). In this interpretation, the onset temperature for octahedral tilting monotonically increases up to the antiferroelectric transition of PbZrO(3), and the depression of T(T)(x) below x=0.18 would be a consequence of the partial relief of the mismatch between the average cation radii with the initial stage of tilting below T(IT). PMID:21946859

Cordero, F; Trequattrini, F; Craciun, F; Galassi, C

2011-10-19

403

Alteration of crystalline zircon solid solutions: a case study on zircon from an alkaline pegmatite from Zomba-Malosa, Malawi  

NASA Astrophysics Data System (ADS)

A natural, altered zircon crystal from an alkaline pegmatite from the Zomba-Malosa Complex of the Chilwa Alkaline Province in Malawi has been studied by a wide range of analytical techniques to understand the alteration process. The investigated zircon shows two texturally and chemically different domains. Whereas the central parts of the grain (zircon I) appear homogeneous in backscattered electron images and are characterised by high concentrations of trace elements, particularly Th, U, and Y, the outer regions (zircon II) contain significantly less trace elements, numerous pores, and inclusions of thorite, ytttrialite, and fergusonite. Zircon II contains very low or undetectable concentrations of non-formula elements such as Ca, Al, and Fe, which are commonly observed in high concentrations in altered radiation-damaged zircon. U-Pb dating of both zircon domains by LA-ICPMS and SHRIMP yielded statistically indistinguishable U-Pb weighted average ages of 119.3 ± 2.1 (2?) and 118 ± 1.2 (2?) Ma, respectively, demonstrating that the zircon had not accumulated a significant amount of self-irradiation damage at the time of the alteration event. Electron microprobe dating of thorite inclusions in zircon II yielded a Th-U-total Pb model age of 122 ± 5 (2?) Ma, supporting the age relationship between both zircon domains. The hydrothermal solution responsible for the alteration of the investigated zircon was alkaline and rich in CO3 2-, as suggested by the occurrence of REE carbonates and CO2-bearing fluid inclusions. The alteration of the crystalline, trace element-rich zircon is explained by an interface-coupled dissolution-reprecipitation mechanism. During such a process, the congruent dissolution of the trace element-rich parent zircon I was spatially and temporally coupled to the precipitation of the trace element-poor zircon II at an inward moving dissolution-precipitation front. The driving force for such a process was merely the difference between the solubility of the trace element-rich and -poor zircon in the hydrothermal solution. The replacement process and the occurrence of mineral inclusions and porosity in the product zircon II is explained by the thermodynamics of solid solution-aqueous solution systems.

Soman, Aneesh; Geisler, Thorsten; Tomaschek, Frank; Grange, Marion; Berndt, Jasper

2010-12-01

404

Temperature Field Analysis for PZT Pyroelectric Cells for Thermal Energy Harvesting  

PubMed Central

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

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

2011-01-01

405

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

E-print Network

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

Evans, Paul G.

406

Exploratory Study of the Acoustic Performance of Piezoelectric Actuators  

NASA Technical Reports Server (NTRS)

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.

SantaMaria, O. S.; Thurlow, E. M.; Jones, M. G.

1989-01-01

407

Aerosol growth in Titan's ionosphere.  

PubMed

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

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

408

Structure and ferroelectric properties of sputtered Pb(Mn, Nb)O3PZT thin films  

Microsoft Academic Search

Heteroepitaxial thin films of PZT-based ternary perovskite, xPb(Mn,Nb)O3-(1-x)PZT, were fabricated by magnetron sputtering on (001)SrTiO3 and (001)MgO substrates. The heteroepitaxial thin films showed single c- domain \\/single crystal structure and exhibit hard piezoelectric behavior with high Ec, Ec>180kV\\/cm, at x=0.06 for the film thickness, 300nm-5mm. The ternary perovskite thin films showed relaxed structure at the film thickness > 0.5mm. However,

K. Wasa; K. Kawano; H. Adachi; T. Matsushima; K. Nishida; T. Yamamoto; I. Kanno; H. Kotera

2010-01-01

409

Martensitic Mechanism of the Zircon-to-Reidite Transformation  

NASA Astrophysics Data System (ADS)

The mechanism of the zircon-to-reidite transformation is readdressed in light of the defects in shocked zircon. The transition operates via a two-stage mechanism, involving martensitic shearing of SiO4 tetrahedra and displacive rotations of oxygens.

Turner, D.; Langenhorst, F.; Pollok, K.

2014-09-01

410

Polycrystalline Zircon in Lunar Meteorite Dhofar 458: Origin and Implications  

NASA Astrophysics Data System (ADS)

We report the occurrence of a polycrystalline zircon in lunar meteorite Dhofar 458. The texture of the zircon was shock-induced and indicates that the host rock is an impact melt rock. SIMS U-Pb dating gave a recrystallization age of 3.4 Ga.

Zhang, A. C.; Hsu, W. B.; Li, X. H.; Ming, H. L.; Li, Q. L.; Liu, Y.; Tang, G. Q.

2011-03-01

411

Hadean diamonds in zircon from Jack Hills, Western Australia  

Microsoft Academic Search

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

Martina Menneken; Alexander A. Nemchin; Thorsten Geisler; Robert T. Pidgeon; Simon A. Wilde

2007-01-01

412

High sensitivity mapping of Ti distributions in Hadean zircons  

Microsoft Academic Search

Detrital zircons as old as nearly 4.4 Ga from the Jack Hills, Western Australia, offer possible insights into a phase of Earth history for which there exists no known rock record. Ti concentrations of Hadean zircons indicate a spectrum of crystallization temperatures that range from a cluster at ca. 680 °C to apparent values exceeding 1200 °C. The low temperature

T. Mark Harrison; Axel K. Schmitt

2007-01-01

413

Systematics of internal zircon morphology in major Variscan granitoid types  

Microsoft Academic Search

The internal morphologies of zircon crystals from different types of granitoids (alkaline, calcalkaline and anatectic) are revealed by cathodoluminescence imaging and are described in terms of growth rates of the crystal faces relative to each other. Zircons in the alkaline granitoids are characterized by high and constant growth rates of {010} relative to the pyramidal forms and by symmetric grwoth

Gerhard Vavra

1994-01-01

414

Chemistry and evolution of Titan's atmosphere  

NASA Technical Reports Server (NTRS)

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.

Strobel, D. F.

1982-01-01

415

Transient clouds in Titan's lower atmosphere.  

PubMed

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

Griffith, C A; Owen, T; Miller, G A; Geballe, T

1998-10-01

416

Chemical investigation of Titan and Triton tholins  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

417

Acceleration of electrons in Titan's ionosphere  

NASA Astrophysics Data System (ADS)

A consideration of the acceleration mechanism which supplies the fast electrons to the source of Saturnian kilometric radiation (SKR) and an interpretation of the recently reported observational indications of the influence of Titan on the SKR are presented. The proposed mechanism operates by the effect of the different magnetization of the electrons and ions in Titan's ionosphere which in the course of Titan's motion through the Saturnian magnetic field causes the creation of a charge-separation electric field. This field has a component parallel to the magnetic field and accelerates part of the ionospheric electrons (called “runaway electrons”). The performed estimates show that the mechanism accelerates the runaway electrons up to an energy of ˜5 keV. The power of the acceleration mechanism is sufficient for SKR generation and also for the ultraviolet luminescence of Titan's atmosphere. The weakening of the SKR when Titan passes on the dayside of Saturn is due to a decrease of the magnetic field strength near the dayside magnetopause, when the Moon escapes the Saturnian magnetosphere, as well as due to the break in the magnetic connection between the electron acceleration region on Titan and the SKR sources. The latter prevents the penetration of the accelerated electrons into the radiation generation region. When Titan is on the nightside of Saturn, it enters into shell L˜14, which is stretched owing to the ring current. In this case, the electrons that accelerated in the ionosphere of Titan can reach the nightside SKR sources and activate them and therefore being the reason for the Titan influence on the SKR.

Zaitsev, V. V.; Shaposhnikov, V. E.; Khodachenko, M. L.; Rucker, H. O.; Panchenko, M.

2010-03-01

418

Recent Origin of Titan's Orbital Eccentricity  

NASA Astrophysics Data System (ADS)

Saturn's regular satellite system contains several dynamical mysteries, including the high tidal heating of Enceladus and undamped eccentricity of Titan. Lainey et al.(2012) proposed that the tidal evolution of the system is much faster than previously thought, which would explain heating of Enceladus and implies that some of the current satellites are less than 1 Gyr old. Cuk et al.(2014) pointed out that this fast tidal evolution could also explain the Titan-Hyperion resonance. If the inner, mid-sized Saturnian moons were re-accreted within the last Gyr, then the same event could have generated the observed eccentricity of Titan. Titan-Hyperion resonance puts strong constraints on this event, as many scenarios lead to the loss of Hyperion (usually through collision with Titan). Here I report on the ongoing study of the history of the Saturnian system, using symplectic integrators SIMPL (for stable configurations) and COMPLEX (for situations when the moons' orbits crossed). I find that the past system of icy satellites could have naturally evolved into instability, by having Dione and Rhea-like moons enter the mutual 4:3 resonance. This resonance is chaotic due to overlap with the solar evection resonance (i.e. the moons' precession rates in the mean-motion resonance overlap with Saturn's mean motion). The outcome of such resonance is a collision between the mid-sized moons, likely followed by re-accretion, with Titan being largely unaffected. I also find that close encounters between a mid-sized moon and Titan could with significant probability both excite Titan and preserve its resonance with Hyperion (cf. Hamilton 2013). I will present possible scenarios in which the previous system had an additional moon exterior to Rhea. This additional moon would have been destabilized by resonances with the inner moons and eventually absorbed by Titan, which acquired its eccentricity in the process. This research is supported by NASA's Outer Planet Research Program.

Cuk, Matija

2014-05-01

419

The Pickup of Titan’s Ionospheric Ions into Saturn’s Magnetosphere  

NASA Astrophysics Data System (ADS)

Previous results from the Cassini Plasma Spectrometer (CAPS) have indicated that Titan’s ionosphere does not appear to contribute significantly to Saturn’s magnetospheric ion population. Cassini orbits intercepting Titan’s orbital path show no obvious evidence of a “nitrogen ion torus”, in contrast to, say, the sulfur ion torus at Jupiter that exists along Io’s orbital path. On the other hand, CAPS and the Ion Neutral Mass Spectrometer (INMS) clearly detect a large and cold population of nitrogen and methane ions in the near vicinity of Titan (e.g. Hartle, et al., 2006; Waite, et al., 2005). We have undertaken a study to determine the extent to which Titan’s ionospheric ions are injected into Saturn’s magnetosphere by summing CAPS ion composition data over multiple encounters and exploring the evolution of both ion populations as a function of distance from Titan. In this study we seek evidence for the entrainment of nitrogen and methane ions into the hotter, co-rotating magnetospheric plasma. Our preliminary results reveal evidence of ion pickup as far as 10 Titan radii (~0.4 RS) from Titan, but no further. At this distance, nitrogen ions have a mean energy of ~600 eV, as compared to the mean energy of the bulk magnetospheric (water group) ions at this distance from Saturn of ~1-2 keV. The detection of CH4+ from the CAPS data is somewhat ambiguous due to partial aliasing with O+, but preliminary indications show the presence of methane pickup ions out to a few Titan radii. By the time of the Fall AGU meeting, we plan to further refine our detection of methane ions using an independent fitting technique. We also plan to map out the spatial distribution of nitrogen and methane ions with respect to Titan and determine upper limits on the detection thresholds for these ions.

Powell, R. L.; Reisenfeld, D. B.; Crary, F. J.; Sittler, E. C.; Smith, H.; Young, D. T.

2009-12-01

420

Strontium Titanate DC Electric Field Switchable and Tunable Bulk Acoustic Wave Solidly Mounted Resonator  

E-print Network

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

York, Robert A.

421

Plausible surface models for Titan  

NASA Technical Reports Server (NTRS)

Current understanding of the nature of Titan's surface and some new ideas for explaining the curious radar returns from Saturn's largest satellite are reviewed. Pre-Voyager models of the surface, based largely on cosmochemistry and the discovery of atmospheric methane, allowed for a range of possibilities, including pure methane oceans. The Voyager 1 flyby ruled out this last possibility, replacing it with compelling observational arguments in favor of a mixed light hydrocarbon and nitrogen ocean. Ground based radar observations indicated a surprisingly reflective surface which is inconsistent with a hydrocarbon ocean and more reminiscent of the Galilean Satellites. Nonetheless, passive radiometric measurements of the surface do not support the notion that Titan's surface is like that of the Galilean satellites. One of the arguments against hydrocarbon oceans reflecting radar energy is that most solid, complex hydrocarbon and nitriles will be denser than the liquid and sink. Nonetheless, many of the aerosol species will coagulate in highly nonspherical patterns, and some species probably polymerize in long chains. Such chains will have very low sedimendation velocities in the ocean and may remain near the surface through ocean mixing process. The prospect of an oceanic 'soup' of polar polymers acting as volume reflectors at radio wevelengths suggests that the interpretation of radar observations needs evaluation.

Lunine, Jonathan I.

1992-01-01

422

Titan's emission processes during eclipse  

NASA Astrophysics Data System (ADS)

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.

Lavvas, P.; West, R. A.; Gronoff, G.; Rannou, P.

2014-10-01

423

Nitrogen in Titan's Atmospheric Aerosol Factory  

NASA Astrophysics Data System (ADS)

Titan's organic aerosols are presumed to contain a large amount of nitrogen as inferred from the in situ measurements of the ACP instrument on board the Huygens probe. They show major emissions of ammonia and hydrogen cyanide after pyrolysis of the refractory nuclei of the atmospheric aerosols. Molecular nitrogen is a rather chemically inert molecule and the processes leading to the high nitrogen content of Titan's aerosols are far from being understood. Here we synthesize the results obtained on Titan's nitrogen composition from analysis of laboratory analogues produced with the PAMPRE experimental setup. These analogues are compared with the in situ measurements of the Cassini CAPS-IBS instrument.

Carrasco, Nathalie; Westlake, Joseph; Pernot, Pascal; Waite, Hunter

424

The greenhouse and antigreenhouse effects on Titan  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

425

Titan's organic chemistry: Results of simulation experiments  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

426

All about Titan and the Huygens Probe  

NSDL National Science Digital Library

This lesson is about Saturn's largest moon, Titan. Learners will listen to a narrative "told" by the Huygens probe, entitled Memoirs of a Spacecraft. Visualization and drawing are used as motivators to enhance comprehension and to get students thinking about Titan and what we might find there. Next, students will read a factual article, entitled All About Titan and the Huygens Probe, and write a summary. This is lesson 8 of 12 in the Mission to Saturn Educators Guide, Reading Writing Rings, for grades 3-4.

427

Planetary science. The weather on Titan.  

PubMed

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

Lorenz, R D

2000-10-20

428

Are there impact-formed zircons in the Hadean record?  

NASA Astrophysics Data System (ADS)

Detrital Hadean zircons from the Jack Hills, Western Australia, show a remarkable cluster of crystallization temperatures at 680±25°C. This is particularly surprising as a simple model relating rock composition and Zr concentration predicts that a very broad spectrum of crystallization temperatures (ca. 650°C to 1000°C) with a median value of 780°C, would result from impact melting of the Earth's surface. Magmatic fractionation would tend to increase the aforementioned values. Given the predicted high rate of impacts during the Hadean, the absence of such a population in the Jack Hills zircons could signal a profound sampling problem, a hint of a history much different than previously supposed, or our lack of understanding of zircon formation due to impact related processes. We have begun to examine the latter issue by investigating the crystallization temperatures of zircons formed in melt sheets preserved in the geologic record. The Sudbury Igneous Complex, formed at 1850±3 Ma within the second largest impact crater on Earth, includes two igneous units termed the Black and Felsic Norites. Examination of zircons from each by SIMS confirms their crystallization age at 1847.3±2.2 Ma and yields Ti-in-zircon temperatures of 720°C and 750°C, respectively. This is consistent with that predicted from zircon saturation systematics. A statistical test indicates that the combined norite population is distinct from the Hadean temperature distribution. Thus the question arises: where are the Hadean zircons expected to have formed at >780°C via impact processes? Similar analysis is being pursued for zircons from the Vredefort Impact Structure, South Africa, which should provide further information on impact-formed zircon temperature spectra.

Wielicki, M. M.; Lu, X.; Bell, E. A.; Schmitt, A. K.; Harrison, T. M.

2008-12-01

429

TSSM: The in situ exploration of Titan  

NASA Astrophysics Data System (ADS)

The Titan Saturn System Mission (TSSM) mission was born when NASA and ESA decided to collaborate on two missions independently selected by each agency: the Titan and Enceladus mission (TandEM), and Titan Explorer, a 2007 Flagship study. TandEM, the Titan and Enceladus mission, was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call. The mission concept is to perform remote and in situ investigations of Titan primarily, but also of Enceladus and Saturn's magentosphere. The two satellites are tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TSSM will study Titan as a system, including its upper atmosphere, the interactions with the magnetosphere, the neutral atmosphere, surface, interior, origin and evolution, as well as the astrobiological potential of Titan. It is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini- Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time for Titan, several close flybys of Enceladus). One overarching goal of the TSSM mission is to explore in situ the atmosphere and surface of Titan. In the current mission architecture, TSSM consists of an orbiter (under NASA's responsibility) with a large host of instruments which would perform several Enceladus and Titan flybys before stabilizing in an orbit around Titan alone, therein delivering in situ elements (a Montgolfière, or hot air balloon, and a probe/lander). The latter are being studied by ESA. The balloon will circumnavigate Titan above the equator at an altitude of about 10 km for several months. The probe will descend through Titan's atmosphere and land on a liquid surface (at the North pole, in a lake according to the current design). The currently envisaged strawman payload for these elements will be presented. Instruments aboard the balloon would provide high resolution vistas of the surface of Titan as the balloon cruises at 10 km altitude, as well as make compositional measurements of the surface, detailed sounding of crustal layering, and chemical measurements of aerosols. A magnetometer, unimpeded by Titan's ionosphere, would permit sensitive detection of induced or intrinsic fields. The short-lived probe would splash into a large northern sea and spend several hours floating during which direct chemical and physical sampling of the liquid—a carrier for many dissolved organic species— would be undertaken. During its descent the Mare Explorer would provide the first in situ profiling of the winter northern hemispheric atmosphere, which is distinctly different from the equatorial atmosphere where Huygens descended and the balloon will arrive. Coordinated radio science experiments aboard the orbiter and in situ elements would be capable of providing detailed information on Titan's tidal response, and hence its crustal rigidity and thickness.

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

2008-09-01

430

Continental crustal history in SE Asia: Insights from zircon geochronology  

NASA Astrophysics Data System (ADS)

It is well known that SE Asia is underlain mostly by continental crust derived from Gondwana. However, there are still many uncertainties about the ages of protoliths, origin, arrival ages and history of different blocks, because much of the basement is unexposed. We have compiled previously published and new zircon U-Pb age and Hf isotope data from SE Asia. Our data set currently contains over 8400 U-Pb ages and over 600 Hf isotope analyses from sedimentary, metamorphic and igneous rocks and work is continuing to increase its size and the area covered. Zircons range in age from 3.4 Ga to near-zero. Archean zircons (>2.5 Ga) are rare in SE Asia and significant Archean populations (particularly zircons >2.8 Ga) are found only in East Java and the Sibumasu block of the Malay Peninsula. The presence of Archean zircons strongly suggests that the East Java and Sibumasu blocks were once situated near present-day Western Australia. Detrital Paleoproterozoic (ca. 1.9-1.8 Ga) zircons are abundant in many parts of SE Asia. In Sundaland (Malay Peninsula, Sumatra, West Java, Borneo) the most likely source for these zircons is the tin belt basement, but a north Australian source is more likely for eastern Indonesian samples. An early Mesoproterozoic (ca. 1.6-1.5 Ga) zircon population, particularly common in eastern Indonesia, is interpreted to be derived from central or northern Australia. Mesoproterozoic zircons, ca. 1.4 Ga, are common only on fragments that are now attached to or were previously part of the north Australian margin, such as the Bird's Head of New Guinea, Timor, Seram, Sulawesi and SW Borneo. Hf isotope characteristics of zircons from Seram are similar to those of zircons from eastern Australia. This supports the suggestion that Seram was part of the Australian margin. Late Meso- and early Neoproterozoic zircons (ca. 1.2-1.1 Ga, 900 Ma, and 600 Ma) are present, but not abundant, in SE Asia. Dominant Phanerozoic populations are Permian-Triassic, Cretaceous, and Cenozoic. All these populations are complex and suggest multiple episodes of magmatism for each. Permian-Triassic detrital zircons were derived from two distinct source areas, the SE Asian tin belt and eastern Indonesia (Banggai-Sula and West Papua). It is notable that in both these areas zircon ages show a gap in magmatism around 260-250 Ma. In West Papua, North Banda and Sulawesi, detrital Triassic zircons are present in many metamorphic rocks, suggesting Triassic or post-Triassic metamorphism in these areas, in rocks previously thought to be Paleozoic or older metamorphic basement. Cretaceous zircons are common in Sumatra, Borneo, Vietnam, Malaysia, Thailand, on the Sunda shelf, and in Sulawesi. They were produced during multiple magmatic events that are unlikely to have a common cause. Cretaceous zircons have also been found in all metamorphic rocks from SW Borneo previously suggested to be Palaeozoic or older. Cenozoic zircons were largely derived from subduction volcanism and are widely distributed, but are a relatively small proportion of the total data set, reflecting a combination of natural, sampling and analytical reasons. Zircon age data suggest that SE Asia records crustal growth mainly by re-assembly of continental fragments rather than by creation of significant new crust.

Sevastjanova, I.; Hall, R.; Gunawan, I.; Ferdian, F.; Decker, J.

2012-12-01

431

Revisited modeling of Titan’s middle atmosphere electrical conductivity  

NASA Astrophysics Data System (ADS)

The atmospheric electrical conductivity measured by the Permittivity, Wave and Altimetry (PWA) subsystem on board the Huygens probe, during the landing mission on Titan, has been modeled in the present work. Previous modeling studies showed a Galactic Cosmic Ray (GCR) peak of conductivity at a higher altitude and a quantitative overestimation in the altitude range 0-100 km compared to that observed by the PWA instrument. Recently the PWA data was revisited and provided new constraints on the conductivity at altitudes 100-180 km. Because the aerosols in the atmosphere are known to alter the electron concentration, using a detailed distribution of the aerosols at all altitudes, the electron conductivity has been calculated in the altitude range 0-180 km. By using a variable range of photoemission threshold for the aerosols, the present model is able to reasonably predict the altitude at which the GCR peak of conductivity occurs and to meet the new constraints for the conductivity profile.

Mishra, Alabhya; Michael, Marykutty; Tripathi, Sachchida Nand; Béghin, Christian

2014-08-01

432

Embedded 3D electromechanical impedance model for strength monitoring of concrete using a PZT transducer  

NASA Astrophysics Data System (ADS)

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.

Wang, Dansheng; Song, Hongyuan; Zhu, Hongping

2014-10-01

433

Application of a passive/active autoparametric cantilever beam absorber with PZT actuator for Duffing systems  

NASA Astrophysics Data System (ADS)

An experimental investigation is carried out on a cantilever-type passive/active autoparametric vibration absorber, with a PZT patch actuator, to be used in a primary damped Duffing system. The primary system consists of a mass, viscous damping and a cubic stiffness provided by a soft helical spring, over which is mounted a cantilever beam with a PZT patch actuator actively controlled to attenuate harmonic and resonant excitation forces. With the PZT actuator on the cantilever beam absorber, cemented to the base of the beam, the auto-parametric vibration absorber is made active, thus enabling the possibility to control the effective stiffness and damping associated to the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies and parametric uncertainty. This active vibration absorber employs feedback information from a high resolution optical encoder on the primary Duffing system and an accelerometer on the tip beam absorber, a strain gage on the base of the beam, feedforward information from the excitation force and on-line computations from the nonlinear approximate frequency response, parameterized in terms of a proportional gain provided by a voltage input to the PZT actuator, thus modifying the closed-loop dynamic stiffness and providing a mechanism to asymptotically track an optimal, robust and stable attenuation solution on the primary Duffing system. Experimental results are included to describe the dynamic and robust performance of the overall closed-loop system.

Silva-Navarro, G.; Abundis-Fong, H. F.; Vazquez-Gonzalez, B.

2013-04-01

434

Understanding Microstructural Effects on Long Term Electrical Fatigue in Multilayer PZT Actuators*  

E-print Network

Understanding Microstructural Effects on Long Term Electrical Fatigue in Multilayer PZT Actuators. However, in order to achieve a maximum displacement in these instances, actuators will be operated of internal strains and the development of micro-cracks. Tailoring the ceramic microstructure by controlled

Balzar, Davor

435

Parallel Beam Micro Sensor\\/Actuator Unit Using PZT Thin Films and its Application Examples  

Microsoft Academic Search

Piezoelectric materials are used for sensors and actuators. It is difficult to form complicated structures with piezoelectric materials, so the actuators and sensors are simple. Using the hydrothermal method, we can fabricate PZT thin film on a three dimensional titanium substrate. We use this feature for actuators and sensors, and made a new sensor\\/actuator unit using this method on a

Toshio Fukuda; Hiroshi Sato; Fumihito Arai; Hitoshi Iwata; Kouichi Itoigawa

1998-01-01

436

Large strain response in PZT-PZN-PAN lead-based ceramics  

NASA Astrophysics Data System (ADS)

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.

Wei, Linlin; Liu, Aiyun; Han, Hailong; Lin, Fangting; Jin, Chengchao; Wang, Peng; Yao, Qirong; Shi, Wangzhou; Jing, Chengbin

2013-12-01

437

PZT/polymer flexible composites for embedded actuator and sensor applications  

NASA Astrophysics Data System (ADS)

Currently, smart structures utilize both polymeric sensor and PZT-based actuators. Polymeric sensors based upon PVDF are limited to about 70 degrees C operating temperature, while PZT-based actuators are inflexible. This paper examines the use of PZT/polymer composites for smart materials applications. Both ferroelectric (VDF) and non- ferroelectric high temperatuer polymers were studied. High temperature composite sensors were fabricated exhibiting g31 values of 90 X 10-3 Vm/N compared to 110 X 10-3 Vm/N for PVDF combined with excellent compliance. On the other hand, 0-3 composite based actuators were fabricated with greatly enhanced d31 over PVDF. Piezo properties and dielectric properties of both sensor and actuators were studied as a function of temperature voltage. Processing-structure-properties relationship was established including key processing parameters such as PZT particle size, enhanced poling additives and polymer properties. Thermal dependence of the 0-3 composites piezoproperties was correlated with glass properties of the polymer. Applications of this new class of 0-3 concepts to cure monitoring of advanced composite systems will be discussed.

Kowbel, Witold; Xia, Xiaoxin; Champion, William; Withers, James C.; Wada, Ben K.

1999-07-01

438

SOI Mass-Sensitive Microresonators with Off-Chip Piezoelectric Excitation by PZT Thick Films  

Microsoft Academic Search

A hybrid system composed by a resonant piezo layer (RPL) and a SOI microelectromechanical system is conceived in this work as highly sensitive mass sensitive sensor for applications in various fields. The idea consists in using PZT screen-printed elements, behaving as thickness-mode resonators to induce oscillations to the micromechanical device and, if the resonance condition is matched for this latter

S. Baglio; V. Ferrari; A. Ghisla; V. Sacco; N. Savalli; A. Taroni

2005-01-01

439

Development of the new shape PZT ceramics sounder suitable for a sound source of artificial larynx  

NASA Astrophysics Data System (ADS)

Various speech production substitutes, which aim to reconstruct speech functions, have been developed and used practically by speech impaired individuals. However, conventional speech production substitutes have various drawbacks; therefore, perfect speech production substitutes are expected to be developed. We focused on the PZT ceramics sounder as a sound source in an electric drive artificial larynx. We first developed the artificial larynx that uses a PZT ceramic sounder and then evaluated its performance. The vocalized sound of the artificial larynx user shows good characteristics at the formant frequency, which is important for vowel discrimination. The characteristic feature of our artificial larynx is its individual structure, and this typical structure implies that the sound source and the implant are separated. This structure facilitates a high biocompatibility in our artificial larynx. In our previous work, the improvement in the acoustic characteristics of the sound source was described. The improvement is achieved by the optimization of the electric control and its structure. In this paper, we present the results of shape optimization and new shape PZT ceramics sounder evaluation. The optimized shape is decided on FEM analysis, and prototype PZT ceramics sounder based on above analysis is manufactured by way of trial. Additionally, the performance of prototype sounder is evaluated by acoustic analysis. Until now, we have researched about the immobilization of biomolecules onto the metal surface. It is believed that biomolecular immobilization on the sound source surface improves its biocompatibility. In the future, we aim to realize implantable sound sources that employ biomolecular immobilization technology.

Ooe, Katsutoshi; Kanetake, Ryota; Sugio, Yuuichi; Tanaka, Akimitsu

2007-12-01

440

Development of PZT and PZN-PT Based Unimorph Actuators for Micromechanical Flapping Mechanisms  

Microsoft Academic Search

This paper focuses on the design, fabrication and charac- terization of unimorph actuators for a microaerial ap- ping mechanism. PZT-5H and PZN-PT are investigated as piezoelectric layers in the unimorph actuators. De- sign issues for microaerial apping actuators are dis- cussed, and criteria for the optimal dimensions of ac- tuators are determined. For low power consumption ac- tuation, a square

Metin Sitti; Domenico Campolo; Joseph Yan; Ronald S. Fearing; Tao Su; David Taylor; Timothy D. Sands

2001-01-01