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1

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

E-print Network

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

2

Array adsorbent-coated lead zirconate titanate (PZT)\\/stainless steel cantilevers for dimethyl methylphosphonate (DMMP) detection  

Microsoft Academic Search

Piezoelectric cantilever sensors consisting of a piezoelectric layer bonded to a non-piezoelectric substrate are sensitive to minute mass changes at the cantilever tip. With simple electrical actuation and sensing, they can be easily miniaturized for array detection. We demonstrated room-temperature detection of dimethyl methylphosphonate (DMMP), a simulant of the nerve agent, sarin, using array lead zirconate titanate (PZT)\\/stainless steel cantilevers

Qiang Zhao; Qing Zhu; Wan Y. Shih; Wei-Heng Shih

2006-01-01

3

High-intensity ultrasound radiation at over 10 MHz using hydrothermal polycrystalline lead zirconate titanate (PZT) thick film transducer  

NASA Astrophysics Data System (ADS)

High intensity at over 10-MHz ultrasonic transducer was fabricated by hydrothermal deposition technique of lead zirconate titanate polycrystalline thick film (HPTF-PZT). The HPTF-PZT ultrasonic transducer had a 0.05-mm-thick PZT layer on a 0.05-mm-thick titanium substrate in an active area of 8 mm ~ 8 mm. The PZT thick film was deposited on a titanium substrate in an autoclave by solution including ions of Pb, Zr and Ti at 160°C. A sound-pressure generation at thickness mode of the HPTF-PZT ultrasonic transducer was investigated in degassed water. This HPTF-PZT ultrasonic transducer could radiate sound pressures of 110 and 30 kPa at 20 and 10 MHz of ten sine waves, respectively. Cavitations and an acoustic streaming were generated when driving signal was 20-MHz continuous sine waves. Additionally, this ultrasonic transducer has the wide frequency response. Consequently, when driving signal was 10 MHz of 10-cycle rectangular waves from an odd order harmonics, the generated sound pressure was 54 kPa higher than 30 kPa at 10 MHz of 10-cycle sine waves. In fact, the HPTF-PZT ultrasonic transducer allows one to radiate high-intensity ultrasound at varied wave form of over 10 MHz.

Ishikawa, Mutsuo; Kurosawa, Minoru; Hasegawa, Tomohito; Endoh, Akito; Takeuchi, Shinichi

2005-09-01

4

Evaluation of Imprint Property of (111)-Highly Oriented Lead Zirconate Titanate (PZT)-Base Ferroelectric Material  

NASA Astrophysics Data System (ADS)

We have investigated the mechanism of static imprint failure in (111)-highly oriented lead zirconate titanate (PZT)-base ferroelectric material by examining the change in the leakage current density. We prepared Pt/Pb(Zr,Ti,Nb)O3 (PZTN)/Pt capacitors. Our capacitors passed the static imprint test at 150°C for 1280 h with a write/read voltage of 3 V or higher. After the static imprint test we measured the leakage current densities of capacitors. All capacitors showed an increase in leakage current density on one side and a decrease on the other side. The side on which leakage current increased depended on the voltage polarity of the write pulse. The changes in leakage current density of capacitors with various write/read voltages indicate that static imprint failure has at least two mechanisms, the contributions of which change according to the write/read voltage. When the write/read voltage is lower, capacitors show diode-like behavior after static imprinting.

Hamada, Yasuaki; Kijima, Takeshi; Miyazawa, Hiromu; Shimoda, Tatsuya

2005-09-01

5

Effect of multi-coating process on the orientation and microstructure of lead zirconate titanate (PZT) thin films derived by chemical solution deposition  

Microsoft Academic Search

This paper describes the effects of multi-coating processes on the orientation, microstructure and electrical property of lead zirconate titanate (PZT) thick films derived by chemical solution deposition. PZT thick films (>1 ?m in thickness) were deposited by various multi-coating processes, such as layer-by-layer crystallization, seed-layering or single-crystallization. The orientation and microstructure of the thick films were characterized by X-ray diffractometry

T. Kobayashi; M. Ichiki; J. Tsaur; R. Maeda

2005-01-01

6

Development of sol-gel derived lead zirconate titanate (PZT) thin films with a nonporous Pt/Ti bottom electrode  

NASA Astrophysics Data System (ADS)

Lead Zirconate Titanate Oxide (PbZrxTi1-xO3 or PZT) thin films have been widely used in various microsensors and microactuators for their high bandwidth and sensitivity. A typical configuration is to use a Pt/Ti bi-layer as the bottom electrode. Before the PZT film is deposited, Pt/Ti bi-layer must be annealed at high temperature (e.g., 800°C) to obtain a condensed structure with a rough micro surface texture. A condensed Pt/Ti structure prevents delamination of the bottom electrode, while a rough micro surface texture ensures PZT thin films anchored firmly onto the bottom electrodes. Although the annealing process is necessary, its high temperature causes Pt/Ti bi-layer to become porous, thus degrading electrical and ferroelectric properties of the PZT thin films. In this paper, we present a non-porous Pt/Ti bottom electrode via a two-step deposition and annealing process. The first step is the traditional fabrication process that leads to a porous Pt/Ti electrode. A second round of deposition and annealing then seals the pores and strengthens the electrode. To evaluate the performance of the non-porous bottom electrode, PZT thin films with porous and non-porous bottom electrodes are fabricated simultaneously. Experimental measurements show that piezoelectric constant d33 of the PZT film increases from 10 pC/N to 20 pC/N when the bottom electrode is changed from the porous to non-porous electrode.

Guo, Qing; Cao, G. Z.; Shen, I. Y.

2011-04-01

7

Electrohydrodynamic deposition of nanostructured lead zirconate titanate.  

PubMed

The deposition of a propanol-based lead zirconate titanate (PZT) sol using electrohydrodynamic atomization (EHDA) in the stable cone-jet mode was investigated. The droplets generated were deposited onto a copper substrate as a film, which was investigated using X-ray diffraction and scanning electron microscopy. The PZT film was shown to contain uniform nano-particles of PZT, which maintained their shape on sintering (650 degrees C, 1 hour) while forming the perovskite phase of PZT. PMID:16433420

Sun, D; Rocks, S A; Edirisinghe, M J; Dorey, R A; Wang, Y

2005-11-01

8

Piezoelectric lead zirconate titanate ceramic fiber\\/polymer composites  

Microsoft Academic Search

This papers on piezoelectric lead zirconate titanate (PZT) ceramic fiber\\/polymer composite were fabricated by a novel technique referred to as relic processing. Basically, this involved impregnating a woven carbon-fiber template material with PZT precursor by soaking the template in a PZT stock solution. Careful heat treatment pyrolized the carbon, resulting in a PZT ceramic relic that retained the fibrous template

David J. Waller; P. Safari

1992-01-01

9

Using the methods of radiospectroscopy (EPR, NMR) to study the nature of the defect structure of solid solutions based on lead zirconate titanate (PZT).  

PubMed

The nature of intrinsic and impurity point defects in lead zirconate titanate (PZT) ceramics has been explored. Using electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) methods, several impurity sites have been identified in the materials, including the Fe(3+)-oxygen vacancy (VO) complex and Pb ions. Both of these centers are incorporated into the PZT lattice. The Fe(3+) –V? paramagnetic complex serves as a sensitive probe of the local crystal field in the ceramic; the symmetry of this defect roughly correlates with PZT phase diagram as the composition is varied from PbTiO3 to PbZrO3. NMR spectra (207)Pb in PbTiO3, PbZrO3, and PZT with iron content from 0 to 0.4 wt% showed that increasing the iron concentration leads to a distortion of the crystal structure and to improvement of the electrophysical parameters of the piezoceramics. This is due to the formation of a phase which has a higher symmetry, but at high concentrations of iron (>0.4 wt%), it leads to sharp degradation of electrophysical parameters. PMID:25073145

Bykov, Igor; Zagorodniy, Yuriy; Yurchenko, Lesya; Korduban, Alexander; Nejezchleb, Karel; Trachevsky, Vladimir; Dimza, Vilnis; Jastrabik, Lubomir; Dejneka, Alexander

2014-08-01

10

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

11

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

NASA Astrophysics Data System (ADS)

Mixing 60-70% lead zirconate titanate with 40-30% lead iron tantalate produces a single-phase, low-loss, room-temperature multiferroic with magnetoelectric coupling: (PbZr0.53Ti0.47O3) (1-x)- (PbFe0.5Ta0.5O3)x. The present study combines x-ray scattering, magnetic and polarization hysteresis in both phases, plus a second-order dielectric divergence (to epsilon = 6000 at 475 K for 0.4 PFT; to 4000 at 520 K for 0.3 PFT) for an unambiguous assignment as a C2v-C4v (Pmm2-P4mm) transition. The material exhibits square saturated magnetic hysteresis loops with 0.1 emu/g at 295 K and saturation polarization Pr = 25 ?C/cm2, which actually increases (to 40 ?C/cm2) in the high-T tetragonal phase, representing an exciting new room temperature oxide multiferroic to compete with BiFeO3. Additional transitions at high temperatures (cubic at T>1300 K) and low temperatures (rhombohedral or monoclinic at T<250 K) are found. These are the lowest-loss room-temperature multiferroics known, which is a great advantage for magnetoelectric devices.

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

2011-12-01

12

Microstereolithography of lead zirconate titanate thick film on silicon substrate  

Microsoft Academic Search

The microstereolithography (?SL) of lead zirconate titanate (PZT) thick films on platinum-buffered silicon substrates is reported for the first time in this paper. Crack-free PZT thick films (80–130 ?m thick) have been fabricated by laser direct-write UV polymerization from the HDDA-based UV curable PZT suspensions. The characterization of the fired films shows dielectric permittivities of 120–200, tangent loss of 0.92–2.5%

X. N. Jiang; C. Sun; X. Zhang; B Xu; Y. H Ye

2000-01-01

13

Lithium tantalate\\/lead zirconate titanate composite ultrasonic transducers  

Microsoft Academic Search

Lithium tantalate (LiTaO3)\\/lead zirconate titanate (PZT) ceramic films of thickness about 50 mum have been deposited on stainless-steel substrates using a modified sol-gel process. LiTaO3 powders are dispersed in a PZT sol-gel matrix to form a 0-3 ceramic\\/ceramic composite. The dielectric, electric, and piezoelectric properties have been studied. Ultrasonic pulse-echo measurements using the composite films as piezoelectric ultrasonic transducers demonstrate

Y. Chen; M. Sayer; L. Zou; C.-K. Jen

1999-01-01

14

High aspect ratio plasma etching of bulk lead zirconate titanate  

NASA Astrophysics Data System (ADS)

Lead Zirconate Titanate (PZT) is a high energy density active material with good piezoelectric coefficient and electromechanical coupling constant making it highly suitable for microsystems applications. In this paper, we present a rapid anisotropic high aspect ratio etching process for defining micron size features in PZT. We used an inductively coupled plasma reactive ion etching (ICP-RIE) system employing sulfur hexafluoride (SF6) and argon (Ar) based chemistry. A seed layer of Au/Cr was lithographically patterned onto fine lap finished PZT-4 substrates followed by electrodeposition of a thick 2-5 ?m nickel on the seed layer, which acts as a hard mask during the etching process. The demonstrated technique was used to etch bulk PZT ceramic substrates, thereby opening possibilities for integration of bulk PZT substrates and structures into microsystems. A maximum etch rate of 19 ?m/hr on PZT-4 and 25 ?m/hr for PZT-5A compositions was obtained using 2000 W of ICP power, 475 W of substrate power, 5 sccm of SF 6, and 50 sccm of Ar on PZT substrate. We have also demonstrated a high aspect ratio etch (>5:1) on a 3 ?m feature size. Detailed analysis of the effects of ICP power, substrate power, and the etch gas composition on the etch rate of PZT are also presented in this article.

Subasinghe, Srimath S.; Goyal, Abhijat; Tadigadapa, Srinivas A.

2006-01-01

15

Lead zirconate titanate behaviors in an LDMOS  

NASA Astrophysics Data System (ADS)

The behaviors of lead zirconate titanate (PZT) deposited as the dielectric for high-voltage devices are investigated experimentally and theoretically. The devices demonstrate not only high breakdown voltages above 350 V, but also excellent memory behaviors. A drain current—gate voltage (ID—VG) memory window of about 2.2 V is obtained at the sweep voltages of ±10 V for the 350-V laterally diffused metal oxide semiconductor (LDMOS). The retention time of about 270 s is recorded for the LDMOS through a controlled ID—VG measurement. The LDMOS with memory behaviors has potential to be applied in future power conversion circuits to boost the performance of the energy conversion system.

Zhai, Ya-Hong; Li, Wei; Li, Ping; Li, Jun-Hong; Hu, Bin; Huo, Wei-Rong; Fan, Xue; Wang, Gang

2013-07-01

16

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

17

Lithium tantalate/lead zirconate titanate composite ultrasonic transducers  

NASA Astrophysics Data System (ADS)

Lithium tantalate (LiTaO3)/lead zirconate titanate (PZT) ceramic films of thickness about 50 ?m have been deposited on stainless-steel substrates using a modified sol-gel process. LiTaO3 powders are dispersed in a PZT sol-gel matrix to form a 0-3 ceramic/ceramic composite. The dielectric, electric, and piezoelectric properties have been studied. Ultrasonic pulse-echo measurements using the composite films as piezoelectric ultrasonic transducers demonstrate a broadband frequency response and good signal-to-noise ratio up to a temperature of 368 °C.

Chen, Y.; Sayer, M.; Zou, L.; Jen, C.-K.

1999-04-01

18

Preparacao do titanato zirconato de chumbo a partir dos citratos metalicos. (Preparation of lead titanate zirconate from metal citrates).  

National Technical Information Service (NTIS)

Lead titanate zirconate (PZT) preparation from its metal constituent citrates have been investigated. Metal citrates were obtained by forced precipitation using a dehydration alcohol mixture. Salt solutions of lead nitrate and octahydrated zirconyl chlori...

C. M. R. Bastos

1994-01-01

19

Leakage current evolution versus dielectric thickness in lead zirconate titanate thin film capacitors  

NASA Astrophysics Data System (ADS)

In this paper, the evolution of lead zirconate titanate (PZT) capacitor leakage current mechanism as a function of dielectric thickness has been investigated. It has been pointed out that PZT leakage current switches from Schottky to Poole-Frenkel conduction mechanisms as PZT thickness decreases. The leakage current evolution seems to be dependant on the presence of a dead layer at metal/PZT interface. The dead layer thickness is estimated at about 40 nm. The switch from an interface limited conduction mode to a bulk limited mode can be attributed to the presence of a higher defect concentration in the dead layer in comparison with PZT bulk.

Chentir, Mohamed-Tahar; Bouyssou, Emilien; Ventura, Laurent; Anceau, Christine

2009-03-01

20

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

SciTech Connect

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

Takechi, Seiji; Onishi, Toshiyuki; Minami, Shigeyuki [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki [Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nogami, Ken-ichi [Department of Physics, Dokkyo University School of Medicine, Tochigi 321-0293 (Japan); Ohashi, Hideo [Faculty of Marine Science, Tokyo University of Marine Science and Technology, Tokyo 108-8477 (Japan); Sasaki, Sho [National Astronomical Observatory of Japan, Iwate 023-0861 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Iwai, Takeo [Research Center for Nuclear Science and Technology, The University of Tokyo, Ibaraki 319-1106 (Japan); Gruen, Eberhard; Srama, Ralf [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Okada, Nagaya [Honda Electronics Co., Ltd., Aichi 441-3193 (Japan)

2008-04-15

21

Characterization of lead zirconate titanate ceramics for use in miniature high-frequency (20-80 MHz) transducers  

Microsoft Academic Search

The material properties of lead zirconate titanate (PZT) ceramics for operation in the thickness mode at frequencies as high as 80 MHz are reported. Each of the ceramics tested showed a reduction in k t with increasing frequency. In a fine-grained PZT, values of kt as high as 0.44 were measured at 80 MHz. The effects of grain size were

F. Stuart Foster; Linda K. Ryan; Daniel H. Turnbull

1991-01-01

22

Characteristics of piezoelectric lead zirconate titanate multilayered detector bombarded with hypervelocity iron particles  

NASA Astrophysics Data System (ADS)

A cosmic dust detector is currently being developed using a piezoelectric lead zirconate titanate (PZT) element. The characteristics of the multilayered detector (MD), which was composed of one hundred PZT disks, were investigated by bombarding it with hypervelocity iron particles supplied by a Van de Graaff accelerator. It was confirmed that there was a linear relationship between the signal amplitude observed from MD and the momentum of the particles. As compared with the single-layered detector (SD) that was composed of one PZT disk, it was found that the sensitivity of MD was ˜3 times higher than that of SD within the limits of the experimental conditions.

Takechi, S.; Onishi, T.; Minami, S.; Miyachi, T.; Fujii, M.; Hasebe, N.; Mori, K.; Nogami, K.; Ohashi, H.; Sasaki, S.; Shibata, H.; Iwai, T.; Grün, E.; Srama, R.; Okada, N.

2009-02-01

23

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

24

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

25

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

Microsoft Academic Search

The processing, electromechanical properties, and micro- structure of lead zirconate titanate (PZT) ceramics over the grain-size range of 0.1-10 µm were studied. Using measure- ments over a large temperature range (15-600 K), the rela- tive role of extrinsic contribution (i.e., domain-wall motion) was deduced to be influenced strongly by the grain size, particularly for donor-doped PZT. Analytical transmission electron microscopy

Clive A. Randall; Namchul Kim; John-Paul Kucera; Wenwu Cao; Thomas R. Shrout

2005-01-01

26

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

27

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

28

Detection of high-energy heavy ions using piezoelectric lead zirconate titanate  

SciTech Connect

The characteristics of a radiation detector fabricated with stacks of piezoelectric lead zirconate titanate (PZT) elements were studied by irradiating it with a 400 MeV/n xenon (Xe) beam for various beam pulse durations. This detector is referred to as the multilayered detector (MD). To understand the production mechanism behind the output voltage obtained from the MD, measurement of the spatial distribution of the output signals generated in the MD was attempted. It was found that the amplitude observed was dependent on the number of Xe ions per unit time and the amount of ionization loss energy of Xe ions in PZT.

Takechi, Seiji; Morinaga, Shin-ya; Kurozumi, Atsuma [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki [Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Shibata, Hiromi [Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan); Murakami, Takeshi; Uchihori, Yukio [National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Okada, Nagaya [Honda Electronics Co., Ltd., Aichi 441-3193 (Japan)

2009-04-15

29

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

30

Detection of high-energy heavy ions using piezoelectric lead zirconate titanate  

NASA Astrophysics Data System (ADS)

The characteristics of a radiation detector fabricated with stacks of piezoelectric lead zirconate titanate (PZT) elements were studied by irradiating it with a 400 MeV/n xenon (Xe) beam for various beam pulse durations. This detector is referred to as the multilayered detector (MD). To understand the production mechanism behind the output voltage obtained from the MD, measurement of the spatial distribution of the output signals generated in the MD was attempted. It was found that the amplitude observed was dependent on the number of Xe ions per unit time and the amount of ionization loss energy of Xe ions in PZT.

Takechi, Seiji; Morinaga, Shin-ya; Kurozumi, Atsuma; Miyachi, Takashi; Fujii, Masayuki; Hasebe, Nobuyuki; Shibata, Hiromi; Murakami, Takeshi; Uchihori, Yukio; Okada, Nagaya

2009-04-01

31

Enhanced piezoelectric property of porous lead zirconate titanate ceramics with one dimensional ordered pore structure  

SciTech Connect

Lead zirconate titanate (PZT) ceramics with one dimensional ordered pore structure (1-3 type porous PZT ceramics) were fabricated in this study. The special structure not only enhanced the piezoelectric and dielectric properties effectively but also further decreased the acoustic impedance. All samples exhibited excellent piezoelectric properties despite high porosities. The d{sub 33} value was 608 pC /N (remained 88% that of dense PZT) when the porosity was up to 68.7%. The d{sub 33} value was 690 pC /N (same as dense PZT) when the porosity was 41.7%. The lowest acoustic impedance (Z) reached 1.3 MRayls. These results are promising for improving performance in hydrophones applications.

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

2010-12-15

32

Photoreduction of silver salts on highly heterogeneous lead zirconate titanate  

Microsoft Academic Search

This paper presents the work undertaken to determine the influences on the photo-induced growth of silver nanoclusters on the surfaces of lead zirconate titanate thin films. The lead zirconate titanate films were grown on indium tin oxide coated glass. They exhibited a highly textured surface and can be treated as wide bandgap semiconductors that exhibit ferroelectric behaviour. We show that

P. M. Jones; S. Dunn

2007-01-01

33

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

34

Correlation between electric-field-induced phase transition and piezoelectricity in lead zirconate titanate films  

NASA Astrophysics Data System (ADS)

We observed that electric field induces phase transition from tetragonal to rhombohedral in polycrystalline morphotropic lead zirconate titanate (PZT) films, as reported in 2011 for bulk PZT. Moreover, we evidenced that this field-induced phase transition is strongly correlated with PZT film piezoelectric properties, that is to say the larger the phase transition, the larger the longitudinal piezoelectric coefficient d33,eff. Although d33,eff already reaches 130-150pm/V, our observation suggests that one could obtain larger d33,eff values, namely 250pm/V, by optimizing the field-induced phase transition thanks to composition fine tuning as close as possible to the morphotropic phase boundary.

Kovacova, V.; Vaxelaire, N.; Le Rhun, G.; Gergaud, P.; Schmitz-Kempen, T.; Defay, E.

2014-10-01

35

Dust detector using piezoelectric lead zirconate titanate with current-to-voltage converting amplifier for functional advancement  

NASA Astrophysics Data System (ADS)

This paper describes the concept of a dust monitor using lead zirconate titanate (PZT) ceramics with a large detection area. Its potential as a dust detector is experimentally demonstrated. The dust monitor has a small volume compared to an impact ionization detector with the same detection area, due to the PZT sensor. The PZT sensor, as a traditional device for the in-situ observation of hypervelocity dust particles, has been used for momentum measurement. The hypervelocity impact signals of PZT sensors are typically read by charge-sensitive amplifiers. Instead, we suggest a new method that a current-to-voltage converting amplifier is useful for interpreting the impact signal of a PZT sensor arising from dust particles down to 0.5 ?m in radius. We propose that datasets of dust impacts can be obtained with a higher statistical accuracy, if the new method is applied to instruments on forthcoming interplanetary-space-cruising spacecrafts.

Kobayashi, M.; Miyachi, T.; Hattori, M.; Sugita, S.; Takechi, S.; Okada, N.

2013-03-01

36

Preparation of Lead Zirconate Titanate Thick Films by Arc-Discharged Reactive Ion-Plating Method  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) thick films of 1 to 3 ?m thickness were prepared by an arc-discharged reactive ion-plating (ADRIP) method. Each PZT thick film had a columnar dense structure. The films showed a perovskite single phase without any thermal treatment after deposition. A high plasma density of the arc discharge enabled a high deposition rate of more than 3 ?m/h. The relative dielectric constant (\\varepsilonr) of the PZT thick films with the Zr/Ti=53/47 composition was about 2000. This value was almost equivalent to that of PZT bulk ceramics. The films typically showed well-saturated P-E hysteresis curves with the remanent polarization (Pr) of 44 ?C/cm2 and the coercive field (Ec) of 39 kV/cm. The butterfly-shaped property of the displacement curve, which is caused by the bending motion in the vertical direction on the film surface, was also observed. Furthermore, the PZT thick films with the (100)-dominant orientation could be obtained by depositing them onto (100)-preferred PZT thin layers which were prepared by a chemical solution deposition (CSD) process.

Yasuda, Yoshiaki; Akamatsu, Masahiro; Tani, Masanao; Yoshida, Makoto; Kondo, Ken-ichi; Iijima, Takashi

2001-09-01

37

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

38

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

39

Fracture mechanisms in ferroelectric-ferroelastic lead zirconate titanate (Zr:Ti = 0. 54:0. 46) ceramics  

Microsoft Academic Search

Fracture toughness, {ital K}{sub IC}, of a single-phase commercial lead zirconate titanate (PZT) ceramic of tetragonal structure was measured using the single edge notched beam method above and below the Curie temperature. Domain switching (poling) under electrical and mechanical loading was examined using x-ray diffraction. Surface grinding, electrical poling, and mechanical poling caused crystallographic texture. Similar texture, indicative of domain

Karun Mehta; Anil V. Virkar

1990-01-01

40

Effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate thin films: Experimental evidence and implications  

NASA Astrophysics Data System (ADS)

The effect of polarization fatigue on the Rayleigh coefficients of ferroelectric lead zirconate titanate (PZT) thin film was systematically investigated. It was found that electrical fatigue strongly affects the Rayleigh behaviour of the PZT film. Both the reversible and irreversible Rayleigh coefficients decrease with increasing the number of switching cycles. This phenomenon is attributed to the growth of an interfacial degraded layer between the electrode and the film during electrical cycling. The methodology used in this work could serve as an alternative way for evaluating the fatigue endurance and degradation in dielectric properties of ferroelectric thin-film devices during applications.

Lou, X. J.; Zhang, H. J.; Luo, Z. D.; Zhang, F. P.; Liu, Y.; Liu, Q. D.; Fang, A. P.; Dkhil, B.; Zhang, M.; Ren, X. B.; He, H. L.

2014-09-01

41

Lead zirconate titanate-nickel zink ferrite thick-film composites: obtaining by the screen printing technique and magnetoelectric properties  

NASA Astrophysics Data System (ADS)

Layered thick-film composites containing one lead zirconate titanate (PZT) layer, one nickel zinc ferrite (NZF) layer, two PZT-NZF layers, or three PZT-NZF-PZT layers each 40-50 ?m thick are prepared. The layers are applied by screen printing on a ceramic aluminum oxide substrate with a preformed contact (conducting) layer. The dielectric properties of the composites are studied in the temperature interval 80-900 K and the frequency interval 25 Hz-1 MHz. Polarized samples exhibit piezoelectric, pyroelectric, and magnetoelectric effects. In tangentially magnetized two- and three-layer composites, the magnetoelectric conversion factor equals 57 kV/(m T) at low frequencies and reaches 2000 kV/(m T) at the mechanical resonance frequency.

Bush, A. A.; Shkuratov, V. Ya.; Chernykh, I. A.; Fetisov, Y. K.

2010-03-01

42

Piezoelectric Properties of Polycrystalline Lead Titanate Zirconate Compositions  

Microsoft Academic Search

Detailed data are given for the piezoelectric, elastic, and dielectric properties of lead titanate zirconate ceramic compositions near the rhombohedral-tetragonal phase boundary. These compositions have markedly higher electromechanical coupling factors, remanent ferroelectric charge, and coercive field, than ceramic barium titanate. Another interesting feature is a pronounced change in the free permittivity ¿33T by the poling process; this change is in

D. A. Berlincourt; C. Cmolik; H. Jaffe

1960-01-01

43

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

44

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

45

Fatigue responses of lead zirconate titanate stacks under semibipolar electric cycling with mechanical preload  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) stacks that had an interdigital internal electrode configuration were tested to more than 108 cycles. A 100 Hz semibipolar sine wave with a field range of +4.5/-0.9 kV/mm was used in cycling with a concurrently-applied 20 MPa preload. Significant reductions in piezoelectric and dielectric responses were observed during the cycling depending on the measuring condition. Extensive partial discharges were also observed. These surface events resulted in the erosion of external electrode and the exposure of internal electrodes. Sections prepared by sequential polishing technique revealed a variety of damage mechanisms including delaminations, pores, and etch grooves. The scale of damage was correlated with the degree of fatigue-induced reduction in piezoelectric and dielectric responses. The results from this study demonstrate the feasibility of using a semibipolar mode to drive a PZT stack under a mechanical preload and illustrate the potential fatigue and damages of the stack in service.

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

2010-10-01

46

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

E-print Network

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

Alpay, S. Pamir

47

Strain-Induced Electrical Properties of Lead Zirconate Titanate Thin Films on a Si wafer with Controlled Oxide Electrode Structure  

NASA Astrophysics Data System (ADS)

This paper shows the electrical properties of ferroelectric thin films with large compressive residual stress. In this study, the large compressive strain was applied to lead zirconate titanate (PZT) thin films by designing the bottom electrode structure on a Si wafer. The materials selected for the bottom electrode were lanthanum nickel oxide (LNO) and lanthanum strontium cobalt oxide [LSCO; (La0.5Sr0.5)CoO3] from the viewpoint of thermal expansion coefficients. As a result, the PZT thin films with morphotropic phase boundary (MPB) composition received compressive residual stress up to approximately 0.8 GPa from the bottom electrode even on a Si wafer. The compressive residual stress concomitantly increased with increasing LSCO layer thickness. In addition, the remanent polarization of the PZT thin films increased with increasing compressive residual stress.

Ohno, Tomoya; Ishiduka, Masaaki; Arai, Takashi; Yanagida, Hiroaki; Matsuda, Takeshi; Sakamoto, Naonori; Wakiya, Naoki; Suzuki, Hisao

2012-09-01

48

Interactions between lead-zirconate titanate, polyacrylic acid, and polyvinyl butyral in ethanol and their influence on electrophoretic deposition behavior.  

PubMed

Electrophoretic deposition (EPD) is an attractive method for the fabrication of a few tens of micrometer-thick piezoelectric layers on complex-shape substrates that are used for manufacturing high-frequency transducers. Niobium-doped lead-zirconate titanate (PZT Nb) particles were stabilized in ethanol using poly(acrylic acid) (PAA). With Fourier-transform infrared spectroscopy (FT-IR), we found that the deprotonated carboxylic group from the PAA is coordinated with the metal in the perovskite PZT Nb structure, resulting in a stable ethanol-based suspension. The hydroxyl group from the polyvinyl butyral added into the suspension to prevent the formation of cracks in the as-deposited layer did not interact with the PAA-covered PZT Nb particles. PVB acts as a free polymer in ethanol-based suspensions. The electrophoretic deposition of micro- and nanometer-sized PZT Nb particles from ethanol-based suspensions onto electroded alumina substrates was attempted in order to obtain uniform, crack-free deposits. The interactions between the PZT Nb particles, the PAA, and the PVB in ethanol will be discussed and related to the properties of the suspensions, the deposition yield and the morphology of the as-deposited PZT Nb thick film. PMID:23025567

Kuscer, Danjela; Bakari?, Tina; Kozlev?ar, Bojan; Kosec, Marija

2013-02-14

49

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

SciTech Connect

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

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

2012-01-01

50

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

51

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

52

Electrical fatigue behaviour in lead zirconate titanate: an experimental and theoretical study  

NASA Astrophysics Data System (ADS)

A systematic investigation on electrical fatigue in lead zirconate titanate (PZT) is carried out for different loading frequencies. Experiments are conducted up to 106 cycles to measure the electrical displacement and longitudinal strain on bulk ceramics in the bipolar mode with large electrical loading conditions. A simplified macroscopic model based on physical mechanisms of domain switching is developed to predict the non-linear behaviour. In this model, the volume fraction of a domain is used as the internal variable by considering the mechanisms of domain nucleation and propagation (domain wall movement). The measured material properties at different fatigue cycles are incorporated into the switching model as damage parameters and the classical strain versus electric field and electric displacement versus electric field curves are simulated. Comparison between the experiments and simulations shows that the proposed model can reproduce the characteristics of non-linear as well as fatigue responses.

Bhattacharyya, Mainak; Arockiarajan, A.

2013-08-01

53

Substrate Clamping Effects on Irreversible Domain Wall Dynamics in Lead Zirconate Titanate Thin Films  

SciTech Connect

The role of long-range strain interactions on domain wall dynamics is explored through macroscopic and local measurements of nonlinear behavior in mechanically clamped and released polycrystalline lead zirconate-titanate (PZT) films. Released films show a dramatic change in the global dielectric nonlinearity and its frequency dependence as a function of mechanical clamping. Furthermore, we observe a transition from strong clustering of the nonlinear response for the clamped case to almost uniform nonlinearity for the released film. This behavior is ascribed to increased mobility of domain walls. These results suggest the dominant role of collective strain interactions mediated by the local and global mechanical boundary conditions on the domain wall dynamics. The work presented in this Letter demonstrates that measurements on clamped films may considerably underestimate the piezoelectric coefficients and coupling constants of released structures used in microelectromechanical systems, energy harvesting systems, and microrobots.

Griggio, Flavio [ORNL; Jesse, Stephen [ORNL; Kumar, Amit [ORNL; Ovchinnikov, Oleg S [ORNL; Kim, H. [Pennsylvania State University, University Park, PA; Jackson, T. N. [Pennsylvania State University, University Park, PA; Damjanovic, Dragan [ORNL; Kalinin, Sergei V [ORNL; Trolier-Mckinstry, Susan E [ORNL

2012-01-01

54

Synthesis, formation and characterization of lead zinc niobate–lead zirconate titanate powders via a rapid vibro-milling method  

Microsoft Academic Search

In this study, an approach to synthesizing pyrochlore-free lead zinc niobate – lead zirconate titanate powders with a formula\\u000a xPb(Zn1\\/3Nb2\\/3)O3–(1???x)Pb(Zr1\\/2Ti1\\/2)O3 (when x?=?0.1–0.5) by a mixed oxide synthetic route via a rapid vibro-milling has been developed. The formation of perovskite phase\\u000a in calcined PZN-PZT powders has been investigated as a function of calcination temperature by TG-DTA and XRD techniques. Powder\\u000a morphology

A. Ngamjarurojana; O. Khamman; S. Ananta; R. Yimnirun

2008-01-01

55

Thermal Behaviors and Phase Evolution of Lead Zirconate Titanate Prepared by Sol-Gel Processing: The Role of the Pyrolysis Time before Calcination  

Microsoft Academic Search

Lead zirconate titanate (PZT) (53\\/47) powders were fabricated by the alkoxide-based sol-gel process, and the different drying times (1 and 12 h) at the pyrolysis temperature (3001C) of lead acetate were studied. The different pyrolysis time before calci- nation affects the onset and the violently dominant decomposi- tion temperatures of lead acetate. According to the estimated activation energy results, the

Tien-I Chang; Sheng-Chang Wang; Chuan-Pu Liu; Chen-Fu Lin; Jow-Lay Huangw

2008-01-01

56

Interfacial morphology and domain configurations in 0-3 PZT–Portland cement composites  

Microsoft Academic Search

Cement-based piezoelectric composites have attracted great attention recently due to their promising applications as sensors in smart structures. Lead zirconate titanate (PZT) and Portland cement (PC) composite were fabricated using 60% of PZT by volume. Scanning Electron Microscope and piezoresponse force microscope were used to investigate the morphology and domain configurations at the interfacial zone of PZT–Portland cement composites. Angular

N. Jaitanong; H. R. Zeng; G. R. Li; Q. R. Yin; W. C. Vittayakorn; R. Yimnirun; A. Chaipanich

2010-01-01

57

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

58

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

59

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

E-print Network

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

Smyth, Katherine Marie

2012-01-01

60

Convergent-beam electron diffraction studies of domains in Rhombohedral phase of lead zirconate titanate ceramics  

SciTech Connect

Lead zirconate titanate Pb(Zr{sub x}Ti{sub 1-x})O{sub 3} (PZT) ceramics are ferroelectrics formed as solid solutions between PbTiO{sub 3} and PbZrO{sub 3}. Among the different phases in the ferroelectric state, the primary ones are the Ti{sup +} rich tetragonal (T) phase and the Zr{sup +4} rich rhombohedral (R) phase and the phase boundary between them (x {approx} 0.53). A net polarization for the piezoelectric activity is obtained under an applied field whereby the polarization vectors of individual grains reorient and this process is called poling. The boundary composition is of great technological importance owing to the high piezo eletric activity. It is suggested, that the excellent piezo electric property is due to the coexistence of both the T and R phases which favours easy poling. Domain types in the R phase of PZT ceramic have been identified using the CBED method. However, the fringe contrast at the domain boundaries indicate that the domain walls are inclined. The orientation relation of domain walls is being studied by conventional microscopy contrast and diffraction techniques. 4 refs., 4 figs.

Dass, M.L.A.; Thomas, G.

1987-07-01

61

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

62

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

63

Ferroelectric/ferroelastic behavior and piezoelectric response of lead zirconate titanate thin films under nanoindentation  

SciTech Connect

The electromechanical response of pure lead zirconate titanate (PZT) and Mn-doped PZT thin ferroelectric films under nanoindentation forces of up to 500 mN was investigated. The stress-induced current transients were measured as a function of the externally applied load on films of different thicknesses using a spherical WC-Co cermet indenter of 500 {mu}m nominal radius. It was found that the quasi-static current generated through the direct piezoelectric effect is superimposed with a contribution from irreversible domain processes during the loading/unloading cycle. The film thickness dependency of the electrical transients and an asymmetry of the current-force curves are attributed to the in-plane clamping stress in the films produced by a dissimilar substrate. Analysis of corresponding charge-force hysteresis loops revealed a significant role for the residual stress state on the polarization switching in thin films. By the application of an indentation force, a portion of Barkhausen jumps was empirically estimated to increase as a consequence of reduction of the clamping effect on domains. The Rayleigh hysteretic charge-force curves showed recovery of the charge released during the load-unload stress cycle. For the thicker 700 nm films, the total charge released during loading was fully recovered with weak hysteresis. In contrast, strong in-plane clamping stresses in the 70 nm thick films are suggested to be reponsible for incomplete recovery upon unloading. A considerable domain-wall contribution to the electromechanical response was demonstrated by an enhanced polarization state, which was shown by an increase of the effective piezoelectric coefficient d{sub eff} of about 35% of its initial value for the thin films at a maximum force of 500 mN.

Koval, V.; Reece, M.J.; Bushby, A.J. [Department of Materials, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom)

2005-04-01

64

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

PubMed

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

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

2007-06-15

65

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

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

66

Nonlinearity and scaling behavior in a soft lead zirconate titanate piezoceramic  

NASA Astrophysics Data System (ADS)

Lead oxide-based ferroelectrics, represented by lead zirconate titanate [Pb(Zr,Ti)O3] or PZT), are the most widely used materials for piezoelectric actuators, sensors, and transducers due to their excellent piezoelectric properties. Most of these piezoelectric materials are employed under a variety of strains (stress, electrical field, and temperature). It would thus be interesting to predict their behaviors under different excitations without having to perform too much experimental work, i.e., just carry out a single experiment and still be able to provide the other experimental values. The purpose of this paper has thus been to propose several behavioral laws linking the electrical field, temperature and mechanical stress. The first law rendered it possible to express the mechanical stress by an equivalent electric field [?E???T×P(E,T0)]. Subsequently, a law linking the electrical field and temperature {?E?[2? ×P(E,?0)]×??} was proposed. From these two laws, a third law was identified reflecting the mechanical stress as an equivalent temperature; each expressed by a temperature equivalent stress (T??×??). After experimental validation of these laws, the mapping could be extended in order to predict the polarization behavior in the tensile stress zone as well as that as a function of the negative temperature.

Hajjaji, Abdelowahed; Guyomar, Daniel; Touhtouh, Samira; Pruvost, Sebastien; Boughaleb, Yahia; Rguiti, Mohamed; Courtois, Christian; Leriche, Anne; Benkhouja, Khalil

2010-09-01

67

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

68

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

69

Development of fine scale PZT ceramic fiber\\/polymer shell composite transducers  

Microsoft Academic Search

The relic processing technique was used to fabricate fine-scale piezoelectric lead zirconate titanate (PZT) ceramic fiber\\/polymer shell composites. In this technique sacrificial activated carbon fabrics were soaked in a PZT precursor solution, dried, and heat treated to form piezoceramic relics. Relics were embedded with polymer, which was allowed to cure, and the resulting composites were polished, electroded, and poled. Different

Shai S. Livneh; Victor F. Janas; Ahmad Safari

1995-01-01

70

Structural vibration suppression using PZT patches and higher-order saturation phenomena  

Microsoft Academic Search

This paper presents the study of controlling steady-state vibrations of a cantilevered skew isotropic plate using higher-order saturation phenomena. PZT (lead zirconate titanate) patches are used as control actuators, and a laser vibrometer (measuring velocities) or PZT patches (measuring displacements) are used as sensors. Modal testing, finite element analysis, and a scanning laser vibrometer are used to reveal the plate's

P. Frank Pai; Bernd Rommel; Mark J. Schulz

1999-01-01

71

High-temperature electrical conductivity and point defects in lead zirconate-titanate  

Microsoft Academic Search

The electrical conductivity and thermoelectric power of lead zitconate-titanate Pb(Ti0.47Zr0.53)O3 (PZT) have been studied at temperatures up to 1000°C in gaseous ambients with controlled partial pressures of both volatile components: lead oxide and oxygen. The experimental results show the small polaron conduction mechanism in PZT. The predominant point defects, as obtained from the oxygen pressure dependences of the conductivity and

V. V. Prisedsky; V. I. Shishkovsky; V. V. Klimov

1977-01-01

72

Ion Irradiation Damage in Zirconate and Titanate Ceramics for Pu Disposition  

SciTech Connect

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

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

2004-07-01

73

Growth of highly (100) oriented lead zirconate titanate films on silicon and glass substrates using lanthanum nitrate as a buffer layer  

NASA Astrophysics Data System (ADS)

Highly oriented lead zirconate titanate [Pb(Zr ,Ti)O3; PZT] thin films were deposited on Pt /Ti/SiO2/Si and glass substrates by the sol-gel method using lanthanum nitrate as a buffer layer. When the lanthanum nitrate buffer layer was annealed at temperatures between 450 and 550°C, the PZT layer coated onto this buffer layer showed strong (100) orientation. The film deposited on the buffer layer had this orientation, regardless of the other deposition conditions, such as the pyrolysis temperature, pyrolysis time, annealing temperature, and heating rate. The lanthanum nitrate buffer layer also acted as a very effective diffusion barrier against Pb-Si interdiffusion, thus allowing for the direct deposition of PZT films on Si, SiO2/Si, and glass substrates. Using this buffer layer, highly oriented PZT film was fabricated stably and reproducibly, regardless of substrate material and the coating conditions. The nature of the lanthanum nitrate buffer layer and its role in the growth of the highly (100) oriented PZT films were investigated.

Choi, Jong-Jin; Park, Chee-Sung; Park, Gun-Tae; Kim, Hyoun-Ee

2004-11-01

74

Effect of Uniaxial Stress on Dielectric Properties of 0–3 PZT-Portland Cement Composite  

Microsoft Academic Search

The effects of uniaxial stress on the 0–3 lead zirconate titanate (PZT)-portland cement (PC) composite were investigated. PZT and PC composites were fabricated using 50% of PZT by volume. At room temperature, the dielectric properties were measured under stress free and stress level up to 57 MPa at the frequency of 1–100 kHz. The results showed that the dielectric constant

N. Jaitanong; R. Yimnirun; A. Chaipanich

2009-01-01

75

Effect of pH on the Crystallization of Homogeneously Precipitated Nanosized PZT Powder  

Microsoft Academic Search

Nanosized lead zirconate titanate (PZT) powder with Zr:Ti ratio in the morphotropic phase boundary region was synthesized by homogeneous precipitation of metal ions. The powder precipitated at 90°C and at pH 6.7 resulted single-phase perovskite lead zirconate titanate powder when calcined at 550°C and above for 4 hours in air. The solution pH and the precipitation temperature strongly affect the

S. Roy; S. Bysakh; J. Subrahmanyam

2007-01-01

76

Screen Printed PZT Thick Films Using Composite Film Technology  

Microsoft Academic Search

A spin coating composite sol gel technique for producing lead zirconate titanate (PZT) thick films has been modified for use with screen printing techniques. The resulting screen printing technique can be used to produce 10 ?m thick films in a single print. The resultant films are porous but the density can be increased through the use of repeated sol infiltration\\/pyrolysis

R. A. Dorey; R. W. Whatmore; S. P. Beeby; R. N. Torah; N. M. White

2003-01-01

77

Preparation of Lead Zirconate Titanate Thin Film by Hydrothermal Method  

Microsoft Academic Search

A hydrothermal method for preparing thin films of crystalline PZT was developed by controlling the rates of nucleation and crystal growth. This method consisted of two steps of hydrothermal reaction. The first step (nucleation process) was that in which the TiO2 substrate reacted with the mixed solution of Pb and Zr to form PZT and\\/or PZ nuclei on the surface.

Katsuhiko Shimomura; Takaaki Tsurumi; Yoko Ohba; Masaki Daimon

1991-01-01

78

Phase transitions in polarized heterophase systems based on lead zirconate titanate  

NASA Astrophysics Data System (ADS)

Temperature dependences of the depolarization currents have been studied and phase transformations between the R3 c, R3 m, P4 mm, and Pm3 m phases have been determined in samples of the five-component heterophase ferroelectric ceramics based on lead zirconate titanate.

Milov, E. V.; Akbaeva, G. M.; Gavrilyachenko, V. G.; Semenchev, A. F.

2012-05-01

79

Fabrication of lead zirconate titanate ceramic fibers by gelation of sodium alginate  

Microsoft Academic Search

A novel ceramic fiber processing method by gelation of Na-alginate, a natural innoxious polymer, is reported. The ion exchange reaction between Na and Ca, and associated gelation process is utilized to fabricate lead zirconate titanate piezoelectric ceramic fibers using a Na-alginate based ceramic suspension. Effects of solid loading, viscosity of the starting sodium alginate and its amount in the slurry,

Sedat Alkoy; Hakan Yanik; Bengu Yapar

2007-01-01

80

Design, modeling and optimization of a piezoelectric pressure sensor based on thin-film PZT diaphragm contain of nanocrystalline powders  

Microsoft Academic Search

In this paper fabrication of a 0-3 ceramic\\/ceramic composite lead zirconate titanate, Pb(Zr0.52Ti0.48)O3 thin film has been presented and then a pressure sensor based on multilayer thin-film PZT diaphragm contain of lead zirconate titanate nanocrystalline powders was designed, modeled and optimized. This multilayer diaphragm in general acts as sensor or actuator. ANSYS was used for simulation of diaphragm. Dynamics characteristics

Vahid Mohammadi; M. H. Sheikhi; S. Torkian; A. Barzegar; E. Masumi; Saeide Mohammadi

2009-01-01

81

Direct-write of PZT thick films  

Microsoft Academic Search

Lead zirconate titanate (PZT) thick films have been prepared on alumina substrates using a direct-write technology. Thick films of 50 to 200 ?m were deposited, dried and then sintered at 1000° to 1200°C for 30 minutes in PbO-rich atmosphere. Comparison of the thick film properties revealed that the dielectric constant and remnant polarization of the films sintered at 1100°C were

M. Allahverdi; A. Safari

2004-01-01

82

Sol-Gel PZT for MEMS Applications  

Microsoft Academic Search

Thin-film piezoelectric materials offer an alternative transduction mechanism to electrostatic actuation and capacitive sensing with many attractive advantages for applications in microelectromechanical systems (MEMS). Researchers at the U.S. Army Research Laboratory are utilizing sol-gel deposited lead zirconate titanate (PZT) thin-films in developing several new MEMS technologies, including high frequency filters, magnetometers, micropumps, and pressure sensors. The fabrication procedure and an

Brett Piekarski; Madan Dubey; Eugene Zakar; Ronald Polcawich; Don Devoe; Dennis Wickenden

2002-01-01

83

Low-Field and High-Field Fatigue in PZT-Based Rainbow Actuators  

Microsoft Academic Search

The fatigue characteristics of the electromechanical and ferroelectric properties of high-displacement RAINBOW (Reduced And INternally Biased Oxide Wafer) actuators were investigated. Rainbows were fabricated from three types of lead-zirconate-titanate-based ferroelectric materials: soft ferroelectrics (PZT-SA and PZT-5H), hard ferroelectrics (PZT-4) and slim-loop ferroelectrics (PLZT 9\\/65\\/35). The PZT-4,-5A and-SH compositions were piezoelectric, and PLZT 9\\/65\\/35 was electrostrictive. Before fatigue testing, the flexural

David E. Dausch; Matthew W. Hooker

1997-01-01

84

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

85

Interfacial morphology and domain configurations in 0-3 PZT-Portland cement composites  

NASA Astrophysics Data System (ADS)

Cement-based piezoelectric composites have attracted great attention recently due to their promising applications as sensors in smart structures. Lead zirconate titanate (PZT) and Portland cement (PC) composite were fabricated using 60% of PZT by volume. Scanning Electron Microscope and piezoresponse force microscope were used to investigate the morphology and domain configurations at the interfacial zone of PZT-Portland cement composites. Angular PZT ceramic grains were found to bind well with the cement matrix. The submicro-scale domains were clearly observed by piezoresponse force microscope at the interfacial regions between the piezoelectric PZT phase and Portland cement phase, and are clearer than the images obtained for pure PZT. This is thought to be due to the applied internal stress of cement to the PZT ceramic particle which resulted to clearer images.

Jaitanong, N.; Zeng, H. R.; Li, G. R.; Yin, Q. R.; Vittayakorn, W. C.; Yimnirun, R.; Chaipanich, A.

2010-03-01

86

Photo-reduction of silver salts on highly heterogeneous lead zirconate titanate  

NASA Astrophysics Data System (ADS)

This paper presents the work undertaken to determine the influences on the photo-induced growth of silver nanoclusters on the surfaces of lead zirconate titanate thin films. The lead zirconate titanate films were grown on indium tin oxide coated glass. They exhibited a highly textured surface and can be treated as wide bandgap semiconductors that exhibit ferroelectric behaviour. We show that there is a preferential deposition of silver metal on the ferroelectric films that is related not only to the polarization state of the ferroelectric domains but also to the surface defects such as grain boundaries and defects within the film. The greatest deposition rates are found to occur at grain boundaries where there is an approximately 40:1 ratio of silver clusters when compared to the native positive domains exhibited by the lead zirconate titanate. We propose that the mechanism for cluster growth depends on the availability, and diffusion rate, of electrons into the growing cluster and that the clusters grow from a discrete nucleation point. We also show that the growth of a monolayer of silver is sufficient to prevent the formation of electron-hole pairs by blocking the UV irradiation and that the silver nanoparticles are readily removed from the surface using an ultrasonic bath leading to a possible new method of manufacturing metal nanoparticles.

Jones, P. M.; Dunn, S.

2007-05-01

87

Electric-field-induced reorientation and flip in domain magnetization and light diffraction in an yttrium-iron-garnet/lead-zirconate-titanate bilayer  

NASA Astrophysics Data System (ADS)

A continuous reorientation and an abrupt flip to a canted structure in the magnetization of stripe domains are observed under the influence of an electric field in an yttrium-iron-garnet (YIG)/lead-zirconate-titanate (PZT) bilayer. Magneto-optic techniques have been utilized for the observation of the domain structure and the magnetization flip. It is found that electrically generated mechanical stress in PZT induces an uniaxial anisotropy field in YIG, which is large enough to initially cause a gradual change in the domain magnetization and then a transition from out-of-plane orientation to a canted state for a threshold electric field. Additional evidence for the spin flip has been obtained from data on the modulation of intensity of linearly polarized light due to diffraction by the stripe domains. A comprehensive theory for the voltage-induced magnetization flip is discussed and compared with the data. The magnetic transitions and the theory discussed here are of interests for electric-field-controlled magneto-optic and spintronic devices.

Zavislyak, I. V.; Sohatsky, V. P.; Popov, M. A.; Srinivasan, G.

2013-04-01

88

The Lamb-Wave Device Using PZT Sol-Gel Thin Film for Mass-Loading Sensing  

Microsoft Academic Search

This study presents a Lamb-wave (Flexural Plate Wave, FPW) sensing device using the structure of PZT thin film on silicon membrane. A well-designed FPW device will have less energy dissipating into the sensing fluid and thus is suitable for biosensing. This research adopts the Sol-Gel method to prepare the piezoelectric thin films of lead zirconate titanates (PZT). The propagating membrane

JYH-CHENG YU; Chung-Chia Huang

89

Calculations of giant magnetoelectric effect in multiferroic composites of rare-earth-iron alloys and PZT by finite element method  

Microsoft Academic Search

Magnetoelectric effect of laminated composites of rare-earth-iron alloys (Terfenol-D) and lead–zirconate–titanate (PZT) is calculated by using finite element method. The dependences of the magnetoelectric response on the geometric configuration, the orientations of magnetostriction and polarization, and the applied magnetic field are presented for various sandwiched composites in details. The giant magnetoelectric effect predicted for the Terfenol-D\\/PZT composites is in agreement

Gang Liu; Ce-Wen Nan; Ning Cai; Yuanhua Lin

2004-01-01

90

The Effect of Temperature on Bipolar Electrical Fatigue Behavior of Lead Zirconate Titanate Ceramics  

NASA Astrophysics Data System (ADS)

The ferroelectric fatigue behavior of lead zirconate titanate was investigated under different temperatures (room temperature and 125°C). A bipolar electric field of ±1.5 kV/mm at a frequency of 50 Hz was applied to the samples up to 2 × 105 cycles. A markedly different fatigue rate was observed dependent on temperature. The fatigue degradation represented by the loss of polarization and strain increases with the number of cycles and is more pronounced in the case of the lower temperature. Brennan's model based on a logarithmic fatigue rate is applied to explain the temperature effect on fatigue behavior due to the pinning effect.

Pojprapai, Soodkhet; Glaum, Julia

2012-09-01

91

Dielectric loss peak due to platinum electrode porosity in lead zirconate titanate thin-film capacitors  

NASA Astrophysics Data System (ADS)

Impedance spectroscopy measurements were carried out in situ on lead zirconate titanate capacitors 1.2×1.2 ?m2 in size on a Samsung 4 Mbit 6 in, wafer. We show here that large dielectric loss appears at low frequencies, which is a constriction effect due to the porosity of the platinum electrode. Porous platinum electrodes facilitate an oxygen electrode reaction. The effect may be removed by annealing the platinum electrode at moderate temperature (300 °C). Such an anneal should thus be considered an essential step in the fabrication of a ferroelectric thin-film capacitor on Pt.

Jung, D. J.; Dawber, M.; Ruediger, A.; Scott, J. F.; Kim, H. H.; Kim, Kinam

2002-09-01

92

Crystallization of Lanthanum-Modified Lead Zirconate Titanate (PLZT) Using Coprecipitated Gels  

Microsoft Academic Search

Powders of lanthanum-modified lead zirconate titanate (Pb0.91La0.09)(Zr0.65Ti0.35)0.98O3 (PLZT 9\\/65\\/35) were obtained by calcination of various precursors via chemical coprecipitation methods. The precursors included the coprecipitated gel with the stoichiometric PLZT composition, PbO (powdered chemical reagent)+LZT coprecipitated gel, and mixture of Pb, La, Zr, and Ti individually precipitated gels. Crystallization behaviors of these precursors were examined over the temperature range of

Yao-Jung Lee; Fu-Su Yen; Jong-Ping Wu; Hsing-I Hsiang

1995-01-01

93

PZT Microfibre defect structure studied by Raman spectroscopy  

NASA Astrophysics Data System (ADS)

Raman-scattering spectroscopy on the microscale is proposed as a method to study the distribution of defects and existing vacancies in lead zirconate titanate (PZT) fibres during industrial processes to monitor the volumetric structural order within the fibre and to estimate the spatial phase transition degree from rhombohedral to tetragonal phase. PZT fibres developed in two different sintering atmospheres, PbO and a mixture of PbZrO3 and ZrO2 (PZ+Z), were studied to determine optimal conditions for the production of defect-free PZT fibres. An estimation of defect distribution along the radius of the PZT fibres is presented using Raman spectroscopy and confirmed by x-ray-diffractometry measurements. The degradation of the spatial-mechanical properties is explained by structural changes produced by electrostatic interactions between Zr and Ti ions.

Kozielski, L.; Buixaderas, E.; Clemens, F.; Bujakiewicz-Koro?ska, R.

2010-10-01

94

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

E-print Network

MEMS have found applications in the biomedical field as blood pressure sensors,3 information processingVersity, Princeton, New Jersey 08544-5263 ReceiVed: January 9, 2003 The patterning of sol-gel-derived thin films, nonuniform shrinkage across the film due to the densification of the gel matrix results in "double-peak" film

Aksay, Ilhan A.

95

EFFECTS OF ELECTRIC FIELD ON THE BIAXIAL STRENGTH OF POLED PZT  

SciTech Connect

The mechanical integrity of piezoelectric ceramics plays a crucial role in the performance and design of lead zirconate titanate (PZT) piezo stack actuators especially as PZT actuators become physically larger and are sought to operate under harsher conditions. The reliable design of such systems demands additional consideration of a number of issues that include electro-mechanical coupling as well as strength-size scaling. This study addresses some of those issues through the use of ball-on-ring (BoR) equibiaxial flexure strength tests of two PZT piezo ceramics. The BoR biaxial flexure tests were conducted with two PZT materials under different electric fields. Fracture surfaces and failure initiations were analyzed using optical and scanning electronic microscopy. The effects of electric fields on the two-parameter Weibull distribution are discussed. These results will serve as input data for future probabilistic reliability analysis of multilayer PZT piezo actuators.

Wang, Hong [ORNL; Wereszczak, Andrew A [ORNL

2007-01-01

96

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

97

A role of BNLT compound addition on structure and properties of PZT ceramics  

NASA Astrophysics Data System (ADS)

In this research, effects of lead-free bismuth sodium lanthanum titanate (BNLT) addition on structure and properties of lead zirconate titanate (PZT) ceramics were investigated. PZT ceramics with addition of 0.1-3.0 wt%BNLT were fabricated by a solid-state mixed oxide method and sintering at 1050-1200 °C for 2 h to obtain dense ceramics with at least 96% of theoretical density. X-ray diffraction indicated that complete solid solution occurred for all compositions. Phase identification showed both tetragonal and rhombohedral perovskite structure of PZT with no BNLT phase detected. Scanning electron micrographs of fractured PZT/BNLT ceramics showed equiaxed grain shape with both transgranular and intergranular fracture modes. Addition of BNLT was also found to reduce densification and effectively limited grain growth of PZT ceramic. Optimum Hv and KIC values were found to be 4.85 GPa and 1.56 MPa.m 1/2 for PZT/0.5 wt%BNLT sample. Among PZT/BNLT samples, room temperature dielectric constant seemed to be improved with increasing BNLT content. The maximum piezoelectric coefficient values were observed in pure PZT ceramic and were slightly decreased in BNLT-added samples. Small reduction of remanent polarization and coercive field in hysteresis loops was observed in BNLT-added samples, indicating a slightly suppressed ferroelectric interaction in this material system.

Jaita, P.; Watcharapasorn, A.; Jiansirisomboon, S.

2010-09-01

98

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

99

Optical amplification in Nd3+ doped electro-optic lanthanum lead zirconate titanate ceramics  

NASA Astrophysics Data System (ADS)

As high as 13.0dB single-pass gain was obtained at 1064.4nm in a thin electro-optic ceramic plate of neodymium doped lanthanum-modified lead zirconate titanate (Nd:PLZT). Pumping with a diode laser, gains were achieved in 1.0 and 0.5mol% Nd ion doped samples over a broad seed laser power ranging from tens of nanowatts to tens of milliwatts at room temperature. The broad absorption spectra of Nd:PLZT made it insensitive to the pump wavelength. The Nd:PLZT had a total scattering loss coefficient of less than 0.06cm-1 and exhibited a considerable quadratic electro-optic coefficient greater than 0.30×10-16m2/V2.

Zhang, Jingwen W.; Zou, Yingyin K.; Chen, Qiushui; Zhang, Run; Li, Kewen K.; Jiang, Hua; Huang, Pi-Ling; Chen, Xuesheng

2006-08-01

100

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

101

Domain orientation and piezoelectric properties of Ag doped PMN-PZT ceramics  

Microsoft Academic Search

The hysteresis, dielectric, and piezoelectric properties of ternary 0.5PMN-0.5-PZT (lead magnesium niobate-lead zirconate titanate) ceramics with Ag substitution are described. These ceramics show good square hysteresis loops and thus are promising for thin-film memory applications. At high Ag concentrations the dielectric loss decreased, indicating an increase in the ordering of the structure. A marked increase in the piezoelectric properties, particularly

K. V. R. Murty; S. N. Murty; K. C. Mouli; A. Bhanumathi

1992-01-01

102

Synthesis of precursors for chemical solution deposition of PZT thin films  

Microsoft Academic Search

Lead zirconate titanate precursors involved in the sol–gel synthesis of PZT thin films were prepared from alkoxides of Pb, Zr and Ti, with the same alcoholic radical (methoxyethoxide), obtained by dehydration and alcoholysis of lead acetate, and by alcoholic exchange of zirconium n-propoxide and titanium ethoxide. In this investigation, 1H and 13C NMR spectroscopic techniques and FTIR analysis have been

R. Caruso; O. de Sanctis; A. Frattini; C. Steren; R. Gil

1999-01-01

103

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

104

Dynamics Regulation of a Skew Cantilever Plate Using PZT Patches and Saturation Phenomenon  

Microsoft Academic Search

We investigate the suppression of steady-state vibrations of a cantilevered skew aluminum plate using nonlinear saturation phenomena and PZT (lead zirconate titanate) patches. Finite-element analysis and measurement of operational deflection shapes using a scanning laser vibrometer are performed to study the bending-torsional dynamic characteristics of the plate due to non-rectangular geometry. The control method uses linear second-order controllers coupled to

P. Frank Pai; Bernd Rommel; Mark J. Schulz

2000-01-01

105

Effect of lead zirconate titanate on microstructure, mechanical and electrical properties of bismuth sodium lanthanum titanate ceramics  

NASA Astrophysics Data System (ADS)

Ferroelectric ceramics with formula (Bi0.487Na0.487La0.017)TiO3/xPb(Zr0.52Ti0.48)O3 (when x = 0, 0.1, 0.5, 1.0 and 3.0 wt%) were prepared by solid-state mixed-oxide method and sintered at 1050 - 1200°C for 2 h. The optimum sintering temperature was 1100°C at which all samples had the density at least 98% of theoretical values. X-ray diffraction results suggested that addition of PZT did not significantly affect unit cell of BNLT. An addition of PZT into BNLT effectively increased density and reduced grain size of the ceramics. These changes played an important role on mechanical properties improvement. Room temperature dielectric constant increased with increasing PZT concentration. The addition of PZT into BNLT slightly degraded ferroelectric properties, but improved the piezoelectric properties.

Jaita, P.; Watcharapasorn, A.; Jiansirisomboon, S.

2011-10-01

106

New fabrication of high-frequency (100-MHz) ultrasound PZT film kerfless linear array.  

PubMed

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

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

2013-04-01

107

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

PubMed Central

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

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

2013-01-01

108

Energy harvesting using a PZT ceramic multilayer stack  

NASA Astrophysics Data System (ADS)

In this paper, the interdisciplinary energy harvesting issues on piezoelectric energy harvesting were investigated using a ‘33’ mode (mechanical stress and/or electric field are in parallel to the polarization direction) lead zirconate titanate multilayer piezoelectric stack (PZT-Stack). Key energy harvesting characteristics including the generated electrical energy/power in the PZT-Stack, the mechanical to electrical energy conversion efficiency, the power delivered from the PZT-Stack to a resistive load, the electrical charge/energy transferred from the PZT-Stack to a super-capacitor were systematically addressed. Theoretical models for power generation and delivery to a resistive load were proposed and experimentally affirmed. In a quasi-static regime, 70% generated electrical powers were delivered to matched resistive loads. A 35% mechanical to electrical energy conversion efficiency, which is more than 4 times higher than other reports, for the PZT-Stack had been obtained. The generated electrical power and power density were significantly higher than those from a similar weight and size cantilever-type piezoelectric harvester in both resonance and off-resonance modes. In addition, our study indicated that the capacitance and piezoelectric coefficient of the PZT-Stack were strongly dependent on the dynamic stress.

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2013-06-01

109

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

NASA Astrophysics Data System (ADS)

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 FE phase the R-FE transition line was determined from the field-cooled-field-heated dielectric susceptibilities, while depolarization temperatures were obtained from the field-cooled-zero-field-heated dielectric susceptibilities. A considerably large shift was found for the above two R-FE transition lines demonstrating the strong impact of the electric field on the stability of the FE phase with increasing temperature. It was found that below EC ergodicity is broken due to the divergence of the longest relaxation time at the freezing temperature T0=259 K. Hence the system exhibits a transition line between the ergodic (ER) and nonergodic (NR) relaxor state. In the dc bias field direction of the approach to the FE phase, the temperature dependence of EC, i.e., the transition lines between ER or NR and FE phases were studied by measurements of the complex dielectric constant as a function of a dc bias field at several fixed temperatures. The experimental results are compared with the results of a spherical random bond-random field model of relaxor ferroelectrics.

Bobnar, Vid; Kutnjak, Zdravko; Pirc, Raša.; Levstik, Adrijan

1999-09-01

110

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

Gonzalez-Moran, Carlos O.; Flores-Cuautle, J.J. Agustin; Suaste-Gomez, Ernesto

2010-01-01

111

Blueshift and intensity enhancement of photoluminescence in lead-zirconate-titanate-doped silica nanocomposites  

Microsoft Academic Search

Transparent PbZr0.52Ti0.48O3 (PZT)-doped silica nanocomposites were fabricated via a modified sol-gel process. The nanocomposites were annealed at different temperatures between 740 and 800 °C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO2 matrix was still in an amorphous state. Transmission

S. G. Lu; C. L. Mak; G. K. H. Pang; K. H. Wong; K. W. Cheah

2008-01-01

112

Blueshift and intensity enhancement of photoluminescence in lead-zirconate-titanate-doped silica nanocomposites  

Microsoft Academic Search

Transparent PbZr0.52Ti0.48O3 (PZT)-doped silica nanocomposites were fabricated via a modified sol–gel process. The nanocomposites were annealed at different temperatures between 740 and 800 °C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO2 matrix was still in an amorphous state. Transmission

S G Lu; C L Mak; G K H Pang; K H Wong; K W Cheah

2008-01-01

113

Blue-shift and intensity enhancement of photoluminescence in lead-zirconate-titanate-doped silica nanocomposites.  

PubMed

Transparent PbZr(0.52)Ti(0.48)O(3) (PZT)-doped silica nanocomposites were fabricated via a modified sol-gel process. The nanocomposites were annealed at different temperatures between 740 and 800?°C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO(2) matrix was still in an amorphous state. Transmission electron microscopy confirmed that the PZT particles were of nanosize with perovskite structure and dispersed within the SiO(2) matrix. Photoluminescence spectra of the samples were measured between 10 and 290 K. The pure silica matrix showed an emission band at 3.20 eV and a weak emission band at 2.65 eV. They were noticeably suppressed in the PZT/SiO(2) nanocomposites. An additional emission band at ?2.30 eV, due to transition within the PZT crystallites, was identified. This emission band showed a large blue-shift with decreasing PZT crystallite size and a substantially enhanced intensity as compared with that of bulk PZT ceramics. Our studies demonstrate the typical quantum size effect of ferroelectric-doped nanocomposites and the large influence of the silica matrix on the PL intensity of the embedded PZT particles. PMID:21817587

Lu, S G; Mak, C L; Pang, G K H; Wong, K H; Cheah, K W

2008-01-23

114

Blue-shift and intensity enhancement of photoluminescence in lead-zirconate-titanate-doped silica nanocomposites  

NASA Astrophysics Data System (ADS)

Transparent PbZr0.52Ti0.48O3 (PZT)-doped silica nanocomposites were fabricated via a modified sol-gel process. The nanocomposites were annealed at different temperatures between 740 and 800 °C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO2 matrix was still in an amorphous state. Transmission electron microscopy confirmed that the PZT particles were of nanosize with perovskite structure and dispersed within the SiO2 matrix. Photoluminescence spectra of the samples were measured between 10 and 290 K. The pure silica matrix showed an emission band at 3.20 eV and a weak emission band at 2.65 eV. They were noticeably suppressed in the PZT/SiO2 nanocomposites. An additional emission band at ~2.30 eV, due to transition within the PZT crystallites, was identified. This emission band showed a large blue-shift with decreasing PZT crystallite size and a substantially enhanced intensity as compared with that of bulk PZT ceramics. Our studies demonstrate the typical quantum size effect of ferroelectric-doped nanocomposites and the large influence of the silica matrix on the PL intensity of the embedded PZT particles.

Lu, S. G.; Mak, C. L.; Pang, G. K. H.; Wong, K. H.; Cheah, K. W.

2008-01-01

115

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

PubMed

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. PMID:25173278

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

2014-08-01

116

Improving the piezoelectric properties of thick-film PZT: the influence of paste composition, powder milling process and electrode material  

Microsoft Academic Search

This paper details improvements of the d33 coefficient for thick-film Lead–Zirconate–Titanate (PZT) layers. In particular, the effect that the powder milling process has on particle size, shape and distribution has been investigated. Ball milled, jet milled and attritor milled powders were obtained from Morgan Electro-Ceramics Ltd. These powders were mixed with various ratios of lead borosilicate glass in the range

R. N. Torah; S. P. Beeby; N. M. White

2004-01-01

117

Preisach modelling of nonlinear response in electrically biased lead zirconate titanate-based piezoceramics  

NASA Astrophysics Data System (ADS)

The alteration of the high-field electrical permittivity (nonlinear response) of PZT-based ceramics when an electrical bias field is applied is reported in this work. Large differences are observed between soft and hard PZT behaviours. While in soft PZT a bias field does not modify the nonlinear behaviour, a notable dependence is verified in hard PZT. The Preisach model is satisfactorily used to describe experimental results. A distribution function containing the first terms of the Maclaurin development series of a function composed by two Gaussian-like functions of different amplitudes is proposed. The model gives a satisfactory explanation for the fact that the permittivity depends not only on the amplitude of the applied electric field, but also on the bias field, both for soft and hard ceramics and for poled or unpoled samples.

Ochoa, Diego A.; Pérez, Rafel; García, Jose E.

2013-09-01

118

NOVEL LEAD ZIRCONATE TITANATE COMPOSITE VIA FREEZING TECHNOLOGY FOR HIGH FREQUENCY TRANSDUCER APPLICATIONS  

PubMed Central

Novel PZT-5A ceramic-polymer composite was prepared via freezing technology. This composite exhibited good dielectric and ferroelectric behaviors. At 1 kHz, the dielectric constant and the dielectric loss were 546 and 0.046, respectively, while the remnant polarization was 13.0 ?C/cm2 at room temperature. The electromechanical coupling coefficient (kt) of PZT-5A composite was measured to be 0.54, which is similar to that of PZT piezoelectric ceramic. The piezoelectric coefficient (d33) of PZT-5A composite was determined to be ~250 pC/N. Using this composite, a 58MHz single element transducer with the bandwidth of 70% at ?6dB was built, and the insertion loss was tested to be ?29dB around the central frequency. PMID:21785672

ZHU, B. P.; ZHOU, Q. F.; HU, C. H.; SHUNG, K. K.; GORZKOWSKI, E. P.; PAN, M. J.

2011-01-01

119

Electrical properties of PZT thin films grown by sol–gel and PLD using a seed layer  

Microsoft Academic Search

Lead Zirconate Titanate (PZT) thin films (with molar ratio of Zr:Ti::65\\/35) were deposited by pulsed laser deposition (PLD) and sol–gel technique on Pt\\/Si (111), and Pt\\/Si (100) substrates. A seed layer of PbTiO3 (0.1?m) was coated by sol–gel on the substrates before depositing PZT by PLD and sol–gel. A metal\\/ferroelectric\\/metal (MFM) capacitor structure, formed by depositing gold electrode on top

S. K. Pandey; A. R. James; Chandra Prakash; T. C. Goel; K. Zimik

2004-01-01

120

Substrate effects on domain structures of PZT 30\\/70 sol-gel films via PiezoAFM  

Microsoft Academic Search

Using an atomic force microscope (AFM) modified to perform PiezoAFM we have investigated the piezoelectric response of sol-gel thin film lead zirconate titanate (PZT 30\\/70, PbZr0.3Ti0.7O3) on Pt–Ti\\/SiO2\\/Si, indium tin oxide (ITO)\\/glass and Pt\\/MgO. The films were produced by spin coating a PZT 30\\/70 sol and firing at 520 °C for Pt electrode systems and 600 °C for the ITO system. By

S. Dunn; R. W. Whatmore

2002-01-01

121

Evidence of temperature dependent domain wall dynamics in hard lead zirconate titanate piezoceramics  

NASA Astrophysics Data System (ADS)

This work presents a study of the domain wall dynamics in Pb(Zr1-xTix)O3 (PZT)-based piezoceramics by means of the temperature dependence non-linear dielectric response and hysteresis loop measurements. In soft PZT, non-linear response gradually increases as the temperature is raised. A similar response is displayed by hard PZT at low temperatures. However, rather more complex behavior is detected at temperatures above 200 K. The anomalous response, which is very marked at room temperature, becomes even greater when the electric field is increased. The non-linear dielectric response is analyzed in the framework of the Rayleigh model. The results suggest a clear change in the domain wall dynamics in hard PZT, which is not observed in soft PZT. Observation of the hysteresis loops confirms that a strong effect of domain wall pinning emerges near room temperature. The change in domain wall dynamics appears as the main cause of the dielectric response difference between both kinds of materials at room temperature.

Garcia, J. E.; Ochoa, D. A.; Gomis, V.; Eiras, J. A.; Pérez, R.

2012-07-01

122

Synthesis of highly oriented lead zirconate-lead titanate film using metallo-organics  

SciTech Connect

This paper reports on crack-free Pb(Zr,Ti)O[sub 3] (PZT) thin films with preferred orientation that were prepared successfully on MgO (100), SrTiO[sub 3] (100), and Pt/Ti/SiO[sub 2]/Si substrates from metal alkoxide solutions. Calcination of precursor films in a H[sub 2]O[minus] O[sub 2] gas mixture was found to be effective not only for low-temperature crystallization of perovskite PZT, but also for obtaining the preferred orientation of PZT films. Single-phase PZT films with high preferred orientation were synthesized on MgO (100) and Pt/Ti/SiO[sub 2]/Si substrates at 550[degrees] and 600[degrees] C for 2 h, respectively. The PZT film on the Pt/Ti/Si-O[sub 2]/Si substrate showed a permittivity of 520, tan [delta] of 0.03, a remanent polarization of 24 [mu]C/cm[sup 2], and a coercive field of 54 kV/cm.

Hirano, S.; Yoto, T.; Kikuta, K.; Araki, Y.; Saitoh, M.; Ogasahara, S. (Dept. of Applied Chemistry, School of Engineering, Nagoya Univ., Nagoya 464 (Japan))

1992-10-01

123

Lead zirconium titanate alternatives for nanoactuators.  

PubMed

This paper describes the use of commercially available ceramic capacitors as an alternative for lead-containing and relatively expensive lead zirconate titanate (PZT)- based nanoactuators. A PZT actuator is compared with actuators made from both X5R- and Y5V-type ceramic dielectric capacitors using white light interferometry and a spectrometer. This work is useful because these capacitors can provide an economical nanomotion capability to research laboratories or industrial products. Measuring the displacement of the capacitors is also useful when designing electronic products to ensure undesired operation is not caused by the piezoelectric motion. Additionally, unlike the PZT material, the alternative ceramic materials do not contain lead, which is needed for full compliance with the Restriction on Hazardous Substances (RoHS) initiative. PMID:23287930

Wang, Jin; Elghoul, Gabe; Peters, Stephen

2013-01-01

124

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

125

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.

126

Ultra-thin and isolated dots in polycrystalline lead zirconate titanate films.  

PubMed

Size effects with critical thickness or minimum volume for ferroelectricity are of importance in the application of polycrystalline PZT thin films as future memory devices and as storage media. Isolated dots of perovskite phases in the matrix of pyrochlore were synthesized by isothermal annealing through transformation from amorphous to perovskite. Control of the transformation kinetics allows us to produce the isolated ferroelectric dots with a diameter of 50 nm. Domain structure of the isolated dots is also studied by piezoresponse force microscopy. As prepared, all isolated dots contain perpendicularly polarized monodomains. Domain structures and switching behaviors of the isolated dots are similar to those of the single crystalline PZT films. Polycrystalline PZT films with a thickness of 50 nm were also investigated. They show excellent piezoresponse properties and switching behaviors. Ultra-thin polycrystalline PZT films can play a major role in the application of future ferroelectric memories and field-effect transistors as well as for storage media using the local probe technique. PMID:17186915

Shin, Hyunjung; Lee, Bongki; Kim, Chanhyung; Kim, Seung-Hyun

2006-12-01

127

Thickness of the near-interface regions and central bulk ohmic resistivity in lead lanthanum zirconate titanate ferroelectric thin films  

NASA Astrophysics Data System (ADS)

We have developed a method to separate the low-resistive near-interface regions (NIRs) from the high-resistive central bulk region (CBR) in a ferroelectric thin film. The NIR thickness and the CBR resistivity can thus be accurately determined. Using lanthanum-doped lead zirconate titanate films as an example, we show that the total thickness of the NIRs depends only on the electrode materials in use (Ir and Pt), while the CBR resistivity depends only on the impurity doping levels (La=1.5% and 3%). The fact that the NIR is much narrower when Pt electrodes are used instead of Ir, and that the NIR resistivity is always considerably lower than the central bulk, suggest that the NIRs is probably originated from material nonstoichiometry/defects rather than the band bending at metal/insulator interfaces.

Chu, D. P.; Zhang, Z. G.; Migliorato, P.; McGregor, B. M.; Ohashi, K.; Hasegawa, K.; Shimoda, T.

2002-12-01

128

Memory effect of a mechanical anomaly related to ferroelastic domain switching in rhombohedral lead zirconate titanate ceramics  

SciTech Connect

An anomaly in the temperature dependent mechanical properties of a lead zirconate titanate ferroelectric ceramic has been observed by dynamic mechanical analysis. The anomaly, seen as a rise in modulus, accompanied by a decrease in internal friction, occurs in the low-temperature phase below T{sub C}. The temperature of the anomalies varies systematically with the applied forces and the anomaly does exhibit a memory effect. The corresponding static bending deformation, mainly from remnant strain by ferroelastic domain switching, is analyzed, and a critical remnant strain value for triggering the anomaly is obtained. The anomaly is thought to be induced by pinning and depinning of domain walls. The results confirm that the memory effect and the occurrence of the anomaly are controlled by ferroelastic domain switching.

Wang Can; Redfern, Simon A. T.; Daraktchiev, Maren; Harrison, Richard J. [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ United Kingdom (United Kingdom)

2006-10-09

129

Sol-gel processing of PZT thin films: A review of the state-of-the-art and process optimization strategies  

Microsoft Academic Search

Sol-gel processing has been widely employed for the fabrication of lead zirconate titanate (PZT) thin films. To successfully optimize thin film material properties for different applications, we must develop a fundamental understanding of the processing-property relationships inherent in the sol-gel fabrication process. In the asprepared state, sol-gel thin films are amorphous, have large organic contents, and can possess significant porosity.

Robert W. Schwartz; Timothy J. Boyle; Steven J. Lockwood; Michael B. Sinclair; Duane Dimos; Catherine D. Buchheit

1995-01-01

130

Characterization of PZT Capacitor Structures with Various Electrode Materials Processed In-Situ Using AN Automated, Rotating Elemental Target, Ion Beam Deposition System  

Microsoft Academic Search

Ferroelectric thin film capacitor structures containing lead zirconate titanate (PZT) as the dielectric, with the chemical formula Pb(rm Zr_{x }Ti_{1-x})O_3, were synthesized in-situ with an automated ion beam sputter deposition system. Platinum (Pt), conductive ruthenium oxide (RuO_2), and two types of Pt-RuO_2 hybrid electrodes were used as the electrode materials. The capacitor structures are characterized in terms of microstructure and

Kenneth Douglas Gifford

1994-01-01

131

Interaction of Stern layer and domain structure on photochemistry of lead-zirconate-titanate  

NASA Astrophysics Data System (ADS)

Perovskite ferroelectric materials such as PZT have long been known to have wideband semiconducting properties. It has also been found that they have interesting spatially controllable surface photochemical effects that are not seen in 'normal' semiconductors. This has led to their being studied as possible tools in areas such as metal salt reduction and oxidation for nanoparticle growth. This paper discusses the effects of incident photon energy on the reduction of Ag0 onto PZT(30/70) surfaces with particular emphasis on the part played by energy band bending and the Stern layer. It was found that for increasing photon energy between 4.4 and 5.0 eV both the [1 1 1] and the [1 0 0] orientations of PZT followed a similar trend in that the average Ag0 cluster cross-sectional area increased by a ratio of ca 1.6 to 1. This increase was put down to the higher energy photons exciting more electrons from deeper in the density of states for the material allowing a greater reduction rate of Ag+ at the surface.

Jones, P M; Dunn, S

2009-03-01

132

Limits of formation of random grown perovskite and pyrochlore phases in sol–gel derived La modified lead zirconate titanate thin films  

Microsoft Academic Search

Sol–gel derived La modified lead zirconate titanate (PLZT) films were coated on glass substrates by the dip-coating method. The calcination temperature was varied between 490°C and 650°C for 1 h. Films with different thickness from 170 to 700 nm, in which the crystalline phase was randomly formed, were prepared. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to

Piyi Du; Isabel M Miranda Salvado; Paula M Vilarinho

2000-01-01

133

Influences of temperature and electric field on the bending strength of lead zirconate titanate ceramics  

SciTech Connect

The present work studies the effects of temperature and a d.c. electric field on the bending strength of PZT-841 ceramics using three-point bending measurement. In the temperature range from 30 C to the Curie point T{sub c} ({approximately}272 C), the bending strength as a function of temperature exhibits a valley shape and the valley floors at a temperature around 225 C, revealing a 25% reduction in comparison with the bending strength at room temperature. Meanwhile, elastic compliance and damping factor exhibit peaks, respectively, at 225 C and 220 C, implying a strong correlation between bending strength and compliance. A positive or negative electric field larger than 3 kV/cm reduces the bending strength of PZT-841 ceramics significantly. For example, the bending strength under a positive field of 20 kV/cm is only one half of that without application of any electric field. The electric field is able to fracture mechanically sustained samples. Under a constant load of 70 MPa, the mean value of the critical electric field at fracture is 11.0 kV/cm. A 90{degree}-domain wall kinetic model is herein proposed to understand the observed phenomena.

Fu, R.; Zhang, T.Y.

2000-05-11

134

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

Microsoft Academic Search

Piezoelectric glass-ceramics in the lead zirconate titanato-lead silicate system were developed. SiO2 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

Boen Houng; Chan Young Kim; Michael J. Haun

2000-01-01

135

PZT Thin Film Piezoelectric Traveling Wave Motor  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

136

Phase transition characteristics in PbZrO(3) based PZT-PZN solid solution ceramics.  

PubMed

The ternary oxide solution of lead zirconate titanate (PZT) with a complex perovskite oxide Pb(Zn(1/3)Nb(2/3))O(3 ), (PZN), a composition that is near that of PbZrO(3), was prepared, and its phase transition behavior was investigated. An extension of the ferroelectric phase by the addition of PZN and a change of the transition between two ferroelectric phases from a first-order to a second-order nature are described. PMID:18267618

Lian, J Y; Shiosaki, T

1991-01-01

137

Acoustic-Wave Piezoelectric and Pyroelectric Sensors Based on PZT Thick Films  

Microsoft Academic Search

The operating principles, design and manufacturing in thick-film technology (TFT) of sensors based on the piezoelectric and\\u000a pyroelectric properties of lead zirconate titanate (PZT) thick films are described. In particular, the attention is focused\\u000a on acoustic-wave piezoelectric sensors for physical and chemical quantities, and on pyroelectric sensors and arrays for light\\u000a spot position measurement.\\u000a \\u000a Keywords: piezoelectric sensor, pyroelectric sensor, acoustic-wave

Vittorio Ferrari

138

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

SciTech Connect

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

Hall, D. A.; Mori, T. [School of Materials, University of Manchester, Grosvenor St., Manchester M1 7HS (United Kingdom); Comyn, T. P. [Institute for Materials Research, Woodhouse Lane, University of Leeds, LS2 9JT (United Kingdom); Ringgaard, E. [Meggitt Sensing Systems, Hejreskovvej 18A, 3490 Kvistgaard (Denmark); Wright, J. P. [ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble Cedex (France)

2013-07-14

139

Electron microscopy characterization of lead zirconate titanate ceramics at the morphotropic phase boundary composition  

SciTech Connect

The structure and chemical composition of PZT ceramics prepared by conventional ceramic processing has been analyzed by electron microscopy. Lattice parameters obtained from x-ray diffraction indicate that the T and R phases are only very slightly distorted from cubic symmetry at the MPB composition. Convergent beam diffraction (CBD) has been used to analyze the structure at te MPB composition using the fact that the symmetry of the CBD pattern is sensitive to the point group of the space lattice. It has been established that both T and R phases are present at the MPB composition. Microanalysis using energy dispersive x-ray spectroscopy has been carried out in conjunction with the structure analysis to establish the chemical composition of the different phases present.

Dass, M.L.A.; Dehmen, U.; Thomas, G.; Yamamoto, T.; Okazaki, K.

1986-06-01

140

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

PubMed Central

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

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

2008-01-01

141

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

142

Titan  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

143

Single ZnO nanowire-PZT optothermal field effect transistors.  

PubMed

A new type of pyroelectric field effect transistor based on a composite consisting of single zinc oxide nanowire and lead zirconate titanate (ZnO NW-PZT) has been developed. Under infrared (IR) laser illumination, the transconductance of the ZnO NW can be modulated by optothermal gating. The drain current can be increased or decreased by IR illumination depending on the polarization orientation of the Pb(Zr(0.3)Ti(0.7))O(3) (PZT) substrate. Furthermore, by combining the photocurrent behavior in the UV range and the optothermal gating effect in the IR range, the wide spectrum of response of current by light offers a variety of opportunities for nanoscale optoelectronic devices. PMID:22895012

Hsieh, Chun-Yi; Lu, Meng-Lin; Chen, Ju-Ying; Chen, Yung-Ting; Chen, Yang-Fang; Shih, Wan Y; Shih, Wei-Heng

2012-09-01

144

Single ZnO nanowire-PZT optothermal field effect transistors  

NASA Astrophysics Data System (ADS)

A new type of pyroelectric field effect transistor based on a composite consisting of single zinc oxide nanowire and lead zirconate titanate (ZnO NW-PZT) has been developed. Under infrared (IR) laser illumination, the transconductance of the ZnO NW can be modulated by optothermal gating. The drain current can be increased or decreased by IR illumination depending on the polarization orientation of the Pb(Zr0.3Ti0.7)O3 (PZT) substrate. Furthermore, by combining the photocurrent behavior in the UV range and the optothermal gating effect in the IR range, the wide spectrum of response of current by light offers a variety of opportunities for nanoscale optoelectronic devices.

Hsieh, Chun-Yi; Lu, Meng-Lin; Chen, Ju-Ying; Chen, Yung-Ting; Chen, Yang-Fang; Shih, Wan Y.; Shih, Wei-Heng

2012-09-01

145

Composition and temperature dependence of the dielectric, piezoelectric and elastic properties of pure PZT ceramics.  

PubMed

Pure (undoped) piezoelectric lead zirconate titanate (PZT) ceramic samples at compositions across the ferroelectric region of the phase diagram were prepared from sol-gel-derived fine powders. Excess lead oxide was included in the PZT powders to obtain dense (95-96% of theoretical density) ceramics with large grain size (>7 mum) and to control the lead stoichiometry. The dielectric, piezoelectric, and elastic properties were measured from 4.2 to 300 K. At very low temperatures, the extrinsic domain wall and thermal defect motions freeze out. The low-temperature dielectric data can be used to determine coefficients in a phenomenological theory. The extrinsic contribution to the properties can then be separated from the single-domain properties derived from the theory. PMID:18285000

Zhuang, Z Q; Haun, M J; Jang, S J; Cross, L E

1989-01-01

146

Construction of a PZT Sensor Network for Low and Hypervelocity Impact Detection  

E-print Network

Orbital debris is a constraint on the long-term health of any spacecraft and must be considered during mission planning. Varying mechanisms have been proposed to quantify the problem. Assessment of orbital debris employing ground-based methods such as radar can help determine where debris clouds are located as well as their density or orbital trajectory. Such data is invaluable to computer simulations and can allow predictions of the debris environment over specific time periods [1]. Accurate in-situ data is essential as well with various types of sensors designed to detect orbital debris impacts employed on space missions since the 1950's [2]. One of the most common of these is the PZT (piezoelectric lead zirconate titanate) which is often used in-situ to measure the momentum of a particle at the time of impact. This paper will discuss a multiple PZT sensor system capable of determining both impactor momentum and location currently in development within CASPER.

Carmona, J A; Cooper, M; Schmoke, J; Reay, J; Matthews, L; Hyde, T

2005-01-01

147

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

148

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 (CuNb-VO) and trimeric (VO-CuNb-VO) defect complexes with 180° and non-180° domain walls has been analyzed and compared to the effects from (Cu - VO)(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, Rudiger-A

2014-09-01

149

FAST TRACK COMMUNICATION: Magnetoelectric effect in a Ni-PZT-Ni cylindrical layered composite synthesized by electro-deposition  

NASA Astrophysics Data System (ADS)

Magnetoelectric (ME) coupling of a cylindrical trilayered composite was studied in this paper. A Ni-lead zirconate titanate (PZT)-Ni trilayered cylindrical composite was synthesized by electro-deposition. The maximum ME voltage coefficient of the cylindrical ME composite is 35 V cm-1 Oe-1, about three times higher than that of the plate trilayered composite with the same raw materials and magnetostrictive-piezoelectric phase thickness ratio. The high ME voltage coefficient of the cylindrical composite is due to the self-bound effect of the circle. Moreover, the resulting complex condition can induce a double peak in the field dependence of the ME coefficient.

Pan, D. A.; Bai, Y.; Chu, W. Y.; Qiao, L. J.

2008-01-01

150

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

151

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

152

Pressure-induced ferroelectric-antiferroelectric phase transitions in lead zirconate-tatanate-based solid solutions  

NASA Astrophysics Data System (ADS)

The ferroelectric-antiferroelectric phase transitions induced by hydrostatic pressure in solid solutions based on lead zirconate-titanate (PZT) with introducing 20 at % tin into B sites and composites based on these ceramics have been studied. In the composites with the same composition of solid solution, the transition pressure can be varied within wide ranges depending on the type of binders. The latter is due to the vitrification of the binder and, consequently, the formation of a rigid framework preventing the transmission of pressure to the ceramic matrix.

Spiridonov, N. A.; Ishchuk, V. M.; Kisel', N. G.; Spiridonov, V. N.

2012-05-01

153

A Feasibility Study of PZT Thin-Film Microactuators for Hybrid Cochlear Implants.  

PubMed

Hybrid cochlear implants would integrate electric and acoustic auditory stimulation into a single unit to rehabilitate patients with sensori-neural hearing loss. Conceptually, hybrid cochlear implants consist of an electrode array, as in traditional cochlear implants, and an acoustic microactuator to generate pressure waves inside the cochlea. To enable hybrid cochlear implants, one must develop acoustic actuators small enough to be placed directly into the cochlea. In this study, the microactuators consist of a silicon diaphragm and a Lead-Zirconate-Titanate Oxide (PZT) thin film. Two actuators are tested. For the first actuator, the diaphragm size is 1.1 mm by 1.1 mm, the diaphragm thickness is about 12 m, and the PZT film thickness is 1 ?m. The microactuator is tested in an unloaded condition (in air) and a loaded condition (with water and glass sheets) equivalent to a loading of 17 Pa. The microactuator presents a constant displacement of 16 nm, when the driving voltage is sinusoidal with amplitude of 5 V and frequency ranging from 500 Hz to 10 kHz. For the second actuator, the diaphragm size is 800 ?m by 800 ?m, the diaphragm thickness is 1 ?m, and the PZT film thickness remains 1 m. The second actuator presents a displacement of 6 nm, when the sinusoidal driving voltage is 7.5 V in amplitude. Given that the motion of the stapes in normal hearing is 10-30 nm when the incoming sound pressure is 1 Pa (i.e. PMID:17282598

Lee, Cheng-Chun; Shen, I; Hume, C; Cao, G

2005-01-01

154

PZT piezoelectric films on glass for Gen-X imaging  

NASA Astrophysics Data System (ADS)

The proposed adaptive optics system for the Gen-X telescope uses piezoelectric lead zirconate titanate (PZT) films deposited on flexible glass substrates. The low softening transition of the glass substrates imposes several processing challenges that require the development of new approaches to deposit high quality PZT thin films. Synthesis and optimization of chemical solution deposited 1 ?m thick films of PbZr0.52Ti0.48O3 on small area (1 in2) and large area (16 in2) Pt/Ti/glass substrates has been performed. In order to avoid warping of the glass at temperatures typically used to crystallize PZT films ({700°C), a lower temperature, two-step crystallization process was employed. An {80 nm thick seed layer of PbZr0.30Ti0.70O3 was deposited to promote the growth of the perovskite phase. After the deposition of the seed layer, the films were annealed in a rapid thermal annealing (RTA) furnace at 550°C for 3 minutes to nucleate the perovskite phase. This was followed by isothermal annealing at 550°C for 1 hour to complete crystallization. For the subsequent PbZr0.52Ti0.48O3 layers, the same RTA protocol was performed, with the isothermal crystallization implemented following the deposition of three PbZr0.52Ti0.48O3 spin-coated layers. Over the frequency range of 1 kHz to 100 kHz, films exhibit relative permittivity values near 800 with loss tangents below 0.07. Hysteresis loops show low levels of imprint with coercive fields of 40-50 kV/cm in the forward direction and 50-70 kV/cm in the reverse direction. The remanent polarization varied from 25-35 ?C/cm2 and e31,f values were approximately -5.0 C/m2. In scaling up the growth procedure to large area films, where warping becomes more pronounced due to the increased size of the substrate, the pyrolysis and crystallization conditions were performed in a box furnace to improve the temperature uniformity. By depositing films on both sides of the glass substrate, the tensile stresses are balanced, providing a sufficiently flat surface to continue PZT deposition. The properties of the large area film are comparable to those obtained on small substrates. While sol-gel processing is a viable approach to the deposition of high quality PZT thin films on glass substrates, preliminary results using RF magnetron sputter deposition demonstrate comparable properties with a significantly simpler process that offers a superior route for large scale production.

Wilke, Rudeger H. T.; Trolier-McKinstry, Susan; Reid, Paul B.; Schwartz, Daniel A.

2010-09-01

155

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.

156

Effects of high energy x ray and proton irradiation on lead zirconate titanate thin films' dielectric and piezoelectric response  

SciTech Connect

The effects of irradiation by X rays and protons on the dielectric and piezoelectric response of highly (100)-textured polycrystalline Pb(Zr{sub x}Ti{sub 1-x})O{sub 3} (PZT) thin films have been studied. Low-field dielectric permittivity, remanent polarization, and piezoelectric d{sub 33,f} response all degraded with exposure to radiation, for doses higher than 300 krad. At first approximation, the degradation increased at higher radiation doses, and was stronger in samples exposed to X rays, compared to the proton-irradiated ones. Nonlinear and high-field dielectric characterization suggest a radiation-induced reduction of the extrinsic contributions to the response, attributed to increased pinning of the domain walls by the radiation-induced point defects.

Bastani, Y.; Cortes-Pena, A. Y.; Wilson, A. D. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)] [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Gerardin, S.; Bagatin, M.; Paccagnella, A. [DEI-Department of Information Engineering, University of Padova, Padova 35131 (Italy)] [DEI-Department of Information Engineering, University of Padova, Padova 35131 (Italy); Bassiri-Gharb, N. [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States) [G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2013-05-13

157

Photovoltaic enhancement due to surface-plasmon assisted visible-light absorption at the inartificial surface of lead zirconate-titanate film.  

PubMed

PZT film of 300 nm thickness was deposited on tin indium oxide (ITO) coated quartz by a sol-gel method. Four metal electrodes, such as Pt, Au, Cu and Ag, were used as top electrodes deposited on the same PZT film by sputtering at room temperature. In ITO-PZT-Ag and ITO-PZT-Au structures, the visible light (400-700 nm) can be absorbed partially by a PZT film, and the maximum efficiency of photoelectric conversion of the ITO-PZT-Ag structure was enhanced to 0.42% (100 mW cm(-2), AM 1.5G), which is about 15 times higher than that of the ITO-PZT-Pt structure. Numerical simulations show that the natural random roughness of polycrystalline-PZT-metal interface can offer a possibility of coupling between the incident photons and SPs at the metal surface. The coincidence between the calculated SP properties and the measured EQE spectra reveals the SP origin of the photovoltaic enhancement in these ITO-PZT-metal structures, and the improved photocurrent output is caused by the enhanced optical absorption in the PZT region near the metal surface, rather than by the direct charge-transfer process between two materials. PMID:24477668

Zheng, Fengang; Zhang, Peng; Wang, Xiaofeng; Huang, Wen; Zhang, Jinxing; Shen, Mingrong; Dong, Wen; Fang, Liang; Bai, Yongbin; Shen, Xiaoqing; Sun, Hua; Hao, Jianhua

2014-03-01

158

Effect of buffer layer on the voltage responsivity of the pyroelectric thermal sensors prepared with PZT ceramics  

NASA Astrophysics Data System (ADS)

The pyroelectric thermal detectors were prepared with lead zirconate titanate (PZT) ceramics, where a signal electrode had a structure of Au/metallic buffer/(PZT ceramic). The effect of buffer layer on the voltage responsivity was investigated with a response to step signal, taken by dynamic pyroelectric measurement. Pyroelectric ceramic wafer was prepared by mixed oxide technique. Au layer (thickness: 50 nm) and metallic buffers (thickness: 0 - 20 nm) of Cr, NiCr (80/20), and Ti were prepared by dc magnetron sputtering. In order to improve the light absorptivity, an Au-black was coated on Au signal electrode by thermal evaporation. At steady state, the output voltage (Vo) was decreased with increasing chopping frequency in the range of 1 - 100 Hz. A sensor without buffer showed the severe time-drift and instability in the output signal. However, the sensors with buffer layer showed the stable outputs. For step radiations, rising time (tp), peak voltage (Vp), and initial slope (k) of the output voltage were dependent upon the thickness and materials of buffer layer. The mechanical and electrical contacts between Au electrode and PZT ceramics were improved by inserting the metallic buffer layer. Considering the characteristics of the output voltage, the optimum thickness of buffer layer was about 15 - 20 nm, and the sensors with Ti buffer of 15 - 20 nm in thickness showed the good detectivity. Therefore, the stability and reliability of the thermal sensors could be improved by use of appropriate buffer layer.

Lee, Moon-Ho; Hwang, Ha R.; Bae, Seong-Ho

1997-08-01

159

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

160

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

SciTech Connect

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

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

1995-04-27

161

Optimized pyroelectric properties of 0-3 composites of PZT particles in polyurethane doped with lithium perchlorate.  

PubMed

A substantial improvement in the performance of pyroelectric 0-3 composites of ceramic particles in a polymer matrix has been achieved by doping the polymer matrix material. Readily prepared and polarized films with various volume fractions of lead zirconate-titanate (PZT) particles in polyurethane have been doped in a solution of lithium perchlorate in acetone to increase the conductivity. With an appropriate conductivity, the dielectric permittivities of the ceramic particles and the polymer matrix become matched, resulting in an improvement of the pyroelectric coefficient from about 6 microC/(m(2)K) to about 50 microC/(m(2)K). The experimental results are explained by theoretical predictions. PMID:18276541

Ploss, Bernd; Krause, Markus

2007-12-01

162

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

163

Impedance spectroscopy of PZT ceramics--measuring diffusion coefficients, mixed conduction, and Pb loss.  

PubMed

Sintering of lead zirconate titanate (PZT) at high temperatures results in loss of Pb unless an ambient Pb activity is maintained. The tell-tale sign of Pb loss is an increased conductivity, usually manifested in unacceptably high values of tan?. The conductivity is caused by oxygen vacancies and/or electron holes which are a byproduct of Pb evaporation. In the first part of this paper, it is shown how impedance spectroscopy can be used to separate ionic and electronic conductivity in a properly designed sample by selection of appropriate boundary conditions. Subsequently, impedance is used to probe defect concentrations in PZT during prolonged annealing at 700°C. It is found that oxygen vacancies are generated during annealing in air but the rate of generation actually decreases upon lowering the ambient pO(2). These results are explained by a model of Pb evaporation which, in this case, leads predominantly to oxygen vacancy generation. In principle, this effect could be used to generate a specific vacancy concentration in similar Pb-based oxides. PMID:23007755

Donnelly, Niall J; Randall, Clive A

2012-09-01

164

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

165

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

166

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

NASA Astrophysics Data System (ADS)

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

Griggio, Flavio

167

Characterization of PZT Capacitor Structures with Various Electrode Materials Processed In-Situ Using AN Automated, Rotating Elemental Target, Ion Beam Deposition System  

NASA Astrophysics Data System (ADS)

Ferroelectric thin film capacitor structures containing lead zirconate titanate (PZT) as the dielectric, with the chemical formula Pb(rm Zr_{x }Ti_{1-x})O_3, were synthesized in-situ with an automated ion beam sputter deposition system. Platinum (Pt), conductive ruthenium oxide (RuO_2), and two types of Pt-RuO_2 hybrid electrodes were used as the electrode materials. The capacitor structures are characterized in terms of microstructure and electrical characteristics. Reduction or elimination of non-ferroelectric phases, that nucleate during PZT processing on Pt/TiO _2/MgO and RuO_2/MgO substrates, is achieved by reducing the thickness of the individually deposited layers and by interposing a buffer layer (~100-200A) of PbTiO _3 (PT) between the bottom electrode and the PZT film. Capacitor structures containing a Pt electrode exhibit poor fatigue resistance, irregardless of the PZT microstructure or the use of a PT buffer layer. From these results, and results from similar capacitors synthesized with sol-gel and laser ablation, PZT-based capacitor structures containing Pt electrodes are considered to be unsuitable for use in memory devices. Using a PT buffer layer, in capacitor structures containing RuO_2 top and bottom electrodes and polycrystalline, highly (101) oriented PZT, reduces or eliminates the nucleation of zirconium-titanium oxide, non-ferroelectric species at the bottom electrode interface during processing. This results in good fatigue resistance up to ~2times10^ {10} switching cycles. DC leakage current density vs. time measurements follow the Curie-von Schweidler law, J(t) ~ t^ {rm -n}. Identification of the high electric field current conduction mechanism is inconclusive. The good fatigue resistance, low dc leakage current, and excellent retention, qualifies the use of these capacitor structures in non-volatile random access (NVRAM) and dynamic random access (DRAM) memory devices. Excellent fatigue resistance (10% loss in remanent polarization up to ~2times10^ {10} switching cycles), low dc leakage current, and excellent retention are observed in capacitor structures containing polycrystalline PZT (exhibiting dominant (001) and (100) XRD reflections), a Pt-RuO_2 hybrid bottom electrode (Type IA), and an RuO _2 top electrode. These results, and electrical characterization results on capacitors containing co-deposited Pt-RuO_2 hybrid electrodes (Type II), show potential for application of these capacitor structures in NVRAM and DRAM memory devices.

Gifford, Kenneth Douglas

168

Piezoelectric films using hybrid technology for ultrasonic array and electronic device applications.  

E-print Network

??Lead zirconate titanate (PZT) films are promising for MEMS type micro-devices applications because of their high electromechanical coupling coefficients and excellent piezoelectric properties. PZT piezoelectric… (more)

Chao, Chen.

2008-01-01

169

Fabrication and Characterization of PZT Thick Films for Sensing and Actuation  

PubMed Central

Lead Zirconate Titanate oxide (PZT) thick films with thicknesses of up to 10 mm were developed using a modified sol-gel technique. Usually, the film thickness is less than 1 mm by conventional sol-gel processing, while the electrical charge accumulation which reveals the direct effect of piezoelectricity is proportional to the film thickness and therefore restricted. Two approaches were adopted to conventional sol-gel processing – precursor concentration modulation and rapid thermal annealing. A 10 ?m thick film was successfully fabricated by coating 16 times via this technique. The thickness of each coating layer was about 0.6 mm and the morphology of the film was dense with a crack-free area as large as 16 mm2. In addition, the structure, surface morphology and physical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) and electrical performance. The dielectric constant and hysteresis loops were measured as electric characteristics. This study investigates the actuation and sensing performance of the vibrating structures with the piezoelectric thick film. The actuation tests demonstrated that a 4 mm × 4 mm × 6.5 mm PZT film drove a 40 mm × 7 mm × 0.5 mm silicon beam as an actuator. Additionally, it generated an electrical signal of 60 mVpp as a sensor, while vibration was input by a shaker. The frequencies of the first two modes of the beam were compared with the theoretical values obtained by Euler-Bernoulli beam theory. The linearity of the actuation and sensing tests were also examined.

Jang, Ling-Sheng; Kuo, Kuo-Ching

2007-01-01

170

Effects of electric field on the fracture toughness (KIc) of ceramic PZT  

NASA Astrophysics Data System (ADS)

This work was motivated by the observation that a small percentage of the ceramic lead zirconate titanate (PZT) parts in a device application, one that requires an electrode pattern on the PZT surface, developed fatigue cracks at the edges of the electrodes; yet all of the parts were subjected to similar loading. To obtain additional information on the fracture behavior of this material, similar specimens were run at higher voltage in the laboratory under a microscope to observe the initiation and growth of the fatigue cracks. A sequence of experiments was next performed to determine whether there were fracture toughness variations that depended on material processing. Plates were cut from a single bar in different locations and the Vickers indentation technique was used to measure the relative fracture toughness as a function of position along the bar. Small variations in toughness were found, that may account for some of the devices developing fatigue cracks and not others. Fracture toughness was measured next as a function of electric field. The surface crack in flexure technique was modified to apply an electric field perpendicular to a crack. The results indicate that the fracture toughness drops under a positive electric field and increases under a negative electric field that is less than the coercive field, but as the negative coercive field is approached the fracture toughness drops. Examination of the fracture surfaces using an optical microscope and a surface profilometer reveal the initial indentation crack shape and (although less accurately) the crack shape and size at the transition from stable to unstable growth. These results are discussed in terms of a ferroelastic toughening mechanism that is dependent on electric field.

Goljahi, Sam; Lynch, Christopher S.

2013-09-01

171

Detection of cancer biomarkers by piezoelectric biosensor using PZT ceramic resonator as the transducer.  

PubMed

A novel piezoelectric biosensor using lead titanate zirconate (PZT) ceramic resonator as transducer was developed for label-free, cost-effective, and direct detection of cancer biomarkers. We designed a dual sensing scheme where two ceramic resonators were connected in parallel, in which one resonator was used as the sensing unit and the other as the control unit, in order to minimize environment influences including temperature fluctuation and to achieve the required frequency stability for biosensing applications. Detection of selected cancer biomarkers, such as prostate specific antigen (PSA) and ?-fetoprotein (AFP) was carried out to evaluate the performance of the biosensor. The device showed high sensitivity (0.25 ng/ml) and fast detection (within 30 min) with small amount of sample (1 ?l), which is compatible to that required by clinical measurements. The results also showed that the ceramic resonator-based piezoelectric biosensor platform could be utilized with different chemical interfaces, and the miniaturized size of the ceramic resonators makes it suitable for fabricating sensor arrays for multiplex detection. PMID:23542085

Su, Li; Zou, Lan; Fong, Chi-Chun; Wong, Wing-Leung; Wei, Fan; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

2013-08-15

172

An investigation of vibration-induced protein desorption mechanism using a micromachined membrane and PZT plate.  

PubMed

A micromachined vibrating membrane is used to remove adsorbed proteins on a surface. A lead zirconate titanate (PZT) composite (3 x 1 x 0.5 mm) is attached to a silicon membrane (2,000 x 500 x 3 microm) and vibrates in a flexural plate wave (FPW) mode with wavelength of 4,000/3 microm at a resonant frequency of 308 kHz. The surface charge on the membrane and fluid shear stress contribute in minimizing the protein adsorption on the SiO(2) surface. In vitro characterization shows that 57 +/- 10% of the adsorbed bovine serum albumin (BSA), 47 +/- 13% of the immunoglobulin G (IgG), and 55.3~59.2 +/- 8% of the proteins from blood plasma are effectively removed from the vibrating surface. A simulation study of the vibration-frequency spectrum and vibrating amplitude distribution matches well with the experimental data. Potentially, a microelectromechanical system (MEMS)-based vibrating membrane could be the tool to minimize biofouling of in vivo MEMS devices. PMID:18427993

Yeh, Po Ying; Le, Yevgeniya; Kizhakkedathu, Jayachandran N; Chiao, Mu

2008-10-01

173

Compensator design for hysteresis of a stacked PZT actuator using a congruency-based hysteresis model  

NASA Astrophysics Data System (ADS)

This paper proposes a rate-independent hysteresis compensator for a stacked PZT (lead zirconate titanate) actuator. From a congruency-based hysteresis (CBH) model which is derived from the inherent properties of this actuator, especially the congruency, a feedforward compensator associated with it is developed. The formulation of the proposed compensator is based on an assumption that the inverse operator also possesses the same properties as the CBH model does. This implies that the compensator also possesses properties such as the wiped-out loop closing between the consecutive control points and congruency. Consequently, the expressions for the compensator can be conducted by exploiting the equations for the CBH model in two cases of monotonic increase and monotonic decrease of input excitation. In order to assess the performance of the compensator, several experiments in both open-loop and closed-loop controls are undertaken. In the open-loop control experiment, the performance of the feedforward compensator using the CBH model is compared with the classical Preisach model-based one in three cases of reference waveforms. In the closed-loop control experiment, the proposed compensator is incorporated into a PID (proportional-integral-derivative) control system and the performance of this integrated system is then evaluated and compared to that of the PID with and without compensator.

Nguyen, Phuong-Bac; Choi, Seung-Bok

2012-01-01

174

Low-Temperature Processing of PZT Thick Film by Seeding and High-Energy Ball Milling and Studies on Electrical Properties  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate thick film with molecular formula PbZr0.52Ti0.42O3 (PZT) was prepared by a modified conventional sol-gel method through seeding and high-energy ball milling, resulting in perovskite phase formation at lower temperatures. The ball-milling time was optimized by keeping the seed particle loading (5 wt.%) constant in the sol-gel solution. This methodology helped in reduction of the crystalline phase formation temperature to 300°C, which is much lower than that reported in the literature (450°C). The well-established perovskite phase was confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) of PZT films revealed uniform and crystalline microstructure. Film prepared by this methodology showed higher spontaneous polarization (2.22 ?C/cm2), higher capacitance (1.17 nF), and low leakage current density (18 ?A/cm2). The results obtained from ferroelectric characterization showed a strong correlation with the XRD and SEM results.

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

2013-12-01

175

In-Situ phase and texture characterization of solution deposited PZT thin films during crystallization.  

SciTech Connect

Ferroelectric lead zirconate titanate (PZT) thin films are used for integrated capacitors, ferroelectric memory, and piezoelectric actuators. Solution deposition is routinely used to fabricate these thin films. During the solution deposition process, the precursor solutions are spin coated onto the substrate and then pyrolyzed to form an amorphous film. The amorphous film is then heated at a higher temperature (650-700 C) to crystallize the film into the desired perovskite phase. Phase purity is critical in achieving high ferroelectric properties. Moreover, due to the anisotropy in the structure and properties of PZT, it is desirable to control the texture obtained in these thin films. The heating rate during crystallization process is known to affect the sequence of phase evolution and texture obtained in these thin films. However, to date, a comprehensive understanding of how phase and texture evolution takes place is still lacking. To understand the effects of heating rate on phase and texture evolution, in-situ diffraction experiments during the crystallization of solution deposited PZT thin films were carried out at beamline 6-ID-B, Advanced Photon Source (APS). The high X-ray flux coupled with the sophisticated detectors available at the APS synchrotron source allow for in-situ characterization of phase and texture evolution at the high ramp rates that are commonly used during processing of PZT thin films. A PZT solution of nominal composition 52/48 (Zr/Ti) was spin coated onto a platinum-coated Si substrate (Pt//TiO{sub x}//SiO{sub 2}//Si). The films were crystallized using an infrared lamp, similar to a rapid thermal annealing furnace. The ramp rate was adjusted by controlling the voltage applied to the infrared lamp and increasing the voltage by a constant step with every acquisition. Four different ramp rates, ranging from {approx}1000 C/s to {approx}1 C/s, were investigated. The sample was aligned in grazing incidence to maximize the signal from the thin films. Successive diffraction patterns were acquired with a 1s acquisition time using a MAR SX-165 CCD detector during crystallization. The sample to detector distance and the tilt rotations of the detector were determined in Fit2D{copyright} by using Al{sub 2}O{sub 3} as the calibrant. These corrections were applied to the patterns when binning the data into radial (2{theta}) and azimuthal bins. The texture observed in the thin film was qualitatively analyzed by fitting the intensity peaks along the azimuthal direction with a gaussian profile function to obtain the integrated intensity of the peaks. Data analysis and peak fitting was done using the curve fitting toolbox in MATLAB{copyright}. A fluorite-type phase was observed to form before the perovskite phase for all ramp rates. PtxPb is a transient intermetallic formed due to the interaction of the thin film and the bottom electrode during crystallization. Ramp rate was observed to significantly affect the amount of PtxPb observed in the thin films during crystallization. Ramp rate was also observed to affect the final texture obtained in the thin films. These results will be discussed in the poster in view of the current understanding of these materials.

Brennecka, Geoffrey L.; Nittala, Krishna (University of Florida, Gainesville, FL); Jones, Jacob L. (University of Florida, Gainesville, FL)

2010-08-01

176

Chem-prep PZT 95/5 for neutron generator applicatios : powder preparation characterization utilizing design of experiments.  

SciTech Connect

Niobium doped PZT 95/5 (lead zirconate-lead titanate) is the material used in voltage bars for all ferroelectric neutron generator power supplies. In June of 1999, the transfer and scale-up of the Sandia Process from Department 1846 to Department 14192 was initiated. The laboratory-scale process of 1.6 kg has been successfully scaled to a production batch quantity of 10 kg. This report documents efforts to characterize and optimize the production-scale process utilizing Design of Experiments methodology. Of the 34 factors identified in the powder preparation sub-process, 11 were initially selected for the screening design. Additional experiments and safety analysis subsequently reduced the screening design to six factors. Three of the six factors (Milling Time, Media Size, and Pyrolysis Air Flow) were identified as statistically significant for one or more responses and were further investigated through a full factorial interaction design. Analysis of the interaction design resulted in developing models for Powder Bulk Density, Powder Tap Density, and +20 Mesh Fraction. Subsequent batches validated the models. The initial baseline powder preparation conditions were modified, resulting in improved powder yield by significantly reducing the +20 mesh waste fraction. Response variation analysis indicated additional investigation of the powder preparation sub-process steps was necessary to identify and reduce the sources of variation to further optimize the process.

Lockwood, Steven John; Rodman-Gonzales, Emily Diane; Voigt, James A.; Moore, Diana Lynn

2003-07-01

177

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

178

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

179

Study of magnetic properties and magnetoelectric effect in ( x) Ni 0.5Zn 0.5Fe 2O 4+(1- x)PZT composites  

NASA Astrophysics Data System (ADS)

Magnetoelectric (ME) composites consisting of ferrite phase (x) Ni0.5Zn0.5Fe2O4+ferroelectric phase (1-x)Pb Zr0.8Ti0.2O3 (Lead Zirconate Titanate-PZT) in which x (mol%) varies between 0 and 1 (0.0?x?1.0) was synthesized by double sintering ceramic method. The presence of constituent phases of ferrite, ferroelectric and their composites was confirmed by X-ray diffraction studies. The hysteresis measurement was used to study magnetic properties such as saturation magnetization (MS) and magnetic moment (?B). The existence of single domain (SD) particle in the ferrite phase and mixed (SD+MD) particle in the composites was studied from AC susceptibility measurements. ME voltage coefficient for each mol% of ferrite phase was measured as a function of applied DC magnetic field and at the same time influence of magnetic field on ME response and resistivity of composites was studied. The maximum ME voltage coefficient of 0.84 mV/cm Oe was observed for 15% of ferrite phase and 85% of ferroelectric phase in the composites.

Bammannavar, B. K.; Naik, L. R.

2012-03-01

180

Nanomechanical and Dielectric Properties of Sol-Gel Derived PZT Thin Films Annealed with Microwave Energy  

Microsoft Academic Search

Lead zirconium titanate Pb (Zr0.58Ti0.42) O3 (PZT) thin films were deposited on silicon substrates by sol-gel process. The structural, morphological, dielectric and nano mechanical properties of these films have been studied systematically. The thicknesses of the films were around 160 nm. During the deposition of each layer, the films were baked in a microwave oven which in turn resulted in

A. Rambabu; K. Sudheendran; K. C. James Raju

2010-01-01

181

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.

182

Biologically functionalized nanochannels on ferroelectric lead zirconium titanate surfaces.  

SciTech Connect

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

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

2005-01-01

183

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

NASA Astrophysics Data System (ADS)

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

Leontsev, Serhiy

184

Thermal diffusivity by laser intensity modulation method (LIMM-TD): a novel technique for the determination of thermal diffusivities and conductivities and its application to porous PZT and silica samples.  

PubMed

A modification of a technique for the measurement of the thermal diffusivity of thin solid materials is presented. The technique is called Thermal Diffusivity by Laser Intensity Modulation Method (LIMM-TD). It is based on the measurement of the phase retardation of a thermal wave passing through the test material by means of a lead-zirconate-titanate ceramic (PZT) pyroelectric detector. It is not necessary to know either the pyroelectric coefficient of the detector or the intensity of the laser beam. The method was tested on quartz samples to verify its accuracy. It was then applied to the study of several sets of ceramic samples with porosities of 20, 25, and 30%. One sample set was poled and the pores were partially filled with the fluid used during poling. A second set was not poled. The poled porous samples had thermal conductivities intermediate between that of a commercial dense sample and those of unpoled materials. Thermal diffusivities and conductivities were also measured on micron-thickness porous silica samples. The experimental results were compared with calculations using several composite mixing theories. PMID:18276565

Lang, Sidney B; Ringgaard, Erling; Muensit, Supasarote; Wu, Xiaoqing; Lashley, Jason C; Wong, Yuen-Wah

2007-12-01

185

Bipolar Volcanism on Titan?  

NASA Astrophysics Data System (ADS)

Many circular and irregular depressions in Titan’s polar areas have morphologies consistent with caldera or maar volcanism. If so, concentration of volcanism at Titan’s poles suggests that the low elevations there coincide with thin crusts.

Wood, C. A.

2011-03-01

186

Pb(Zr 0.5, Ti 0.5)O 3 nanofibres by electrospinning  

Microsoft Academic Search

Lead zirconate titanate Pb(Zr0.5, Ti0.5)O3 nanofibres with diameters ranging from 200–300 nm have been synthesized by calcination of the electrospun lead zirconate titanate\\/polyvinyl acetate composite fibres. The morphology and crystalline phase features of these lead zirconate titanate (PZT) nanofibres have been studied by various physico-chemical methods such as SEM, AFM, XRD and FT–IR. The formation of perovskite PZT phase was

N. Dharmaraj; C. H. Kim; H. Y. Kim

2005-01-01

187

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

188

Characterizing Titan's Upper Atmosphere Using the Titan  

E-print Network

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

Johnson, Robert E.

189

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. Hi Hillside Third Graders! Welcome to the Titanic... To watch some videos of the Wreck click on this link below. Scroll down and click on the yellow link above the YouTube screen that says watch more videos. Use the left side of the screen to help you find the word "Wreck Videos". Watch three ...

Law, Miss

2010-04-20

190

Thick film PZT arrays vibration modes  

Microsoft Academic Search

In this work we report some electroacoustic characteristics of miniature piezoelectric ultrasound transducers, manufactured by screen printing and using thick film technology. To make transducer samples, ink with PZT powder and a glass frit was employed. PZT films of 100-130 ?m thick were screen-printed between two gold electrodes over alumina. Electrical impedance and acoustic emission continuous-wave analysis at 1-10 MHz

Sergio Gwirc; Fernanda García; Nicolas Pérez; Carlos Negreira

2002-01-01

191

Perforated PZT composites for hydrophone applications  

Microsoft Academic Search

Macrosymmetry and interphase connectivity have been used to explore the possible macrostructures of interest for piezoelectric composites. Based on these design considerations, PZT-polymer composites with 3-1 and 3-2 connectivity patterns have been fabricated. These composites were prepared by drilling circular and square holes perpendicular to the poling direction in prepoled PZT blocks and filling the holes with epoxy. The influence

A. Safari; S. Davanzo; R. E. Newhham

1983-01-01

192

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

193

Titan Recreation-Titan Bowl and Billiards Student Engagement Report  

E-print Network

Titan Recreation-Titan Bowl and Billiards Student Engagement Report FY 2009-2010 Purpose Statement Titan Recreation strives to enhance participant experiences at CSUF through providing quality physical fitness and overall wellness. Titan Recreation also provides opportunities for cooperative

de Lijser, Peter

194

Titan Recreation-Titan Bowl and Billiards Student Engagement Report  

E-print Network

Titan Recreation-Titan Bowl and Billiards Student Engagement Report FY 2008-2009 Purpose Statement Titan Recreation strives to enhance participant experiences at CSUF through providing quality physical fitness and overall wellness. Titan Recreation also provides opportunities for cooperative

de Lijser, Peter

195

Titan Recreation-Titan Bowl and Billiards Student Engagement Report  

E-print Network

Titan Recreation-Titan Bowl and Billiards Student Engagement Report FY 2012-2013 Purpose Statement Titan Recreation strives to enhance participant experiences at CSUF through providing quality physical fitness and overall wellness. Titan Recreation also provides opportunities for cooperative

de Lijser, Peter

196

Titan Recreation-Titan Bowl and Billiards Student Engagement Report  

E-print Network

Titan Recreation-Titan Bowl and Billiards Student Engagement Report FY 2010-2011 Purpose Statement Titan Recreation strives to enhance participant experiences at CSUF through providing quality physical fitness and overall wellness. Titan Recreation also provides opportunities for cooperative

de Lijser, Peter

197

Anomalous losses of lead in crystallization of the perovskite phase in thin PZT films  

NASA Astrophysics Data System (ADS)

A study has been performed of the mechanisms underlying evolvement of excess lead oxide from lead zirconate titanate films grown ex-situ in two different regimes by magnetron sputtering. In the first case, crystallization of the dense phase of perovskite passed through an intermediate "porous" phase, and in the second, straight through. It has been found that the anomalously large losses of lead are caused by migration of lead over interphase porous boundaries to the surface of the films and depend strongly on the regime of film preparation. The unusual variation of film composition with increasing annealing temperature has been discussed.

Pronin, V. P.; Senkevich, S. V.; Kaptelov, E. Yu.; Pronin, I. P.

2013-01-01

198

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

PubMed Central

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

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

2010-01-01

199

Titan 2D: Understanding Titan’s Seasonal Atmospheric Cycles  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

200

Titanic: A Statistical Exploration.  

ERIC Educational Resources Information Center

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

Takis, Sandra L.

1999-01-01

201

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

202

Isotopic Exchange in Igneous Zircons  

NASA Astrophysics Data System (ADS)

Igneous zircons are a powerful tool for determining crystallization age and metamorphic history of rocks spanning Earth's entire geologic history. High concentrations of uranium and exclusion of lead in zircons make the U-Pb system the primary choice for radiogenic dating. This system has the added advantage of revealing potential parent or daughter loss as discordance on a concordia diagram. For a single mineral grain the U-Pb system reveals not only the age, but an estimate of post-crystallization alteration. As the range of isotopic analyses applied to ancient zircons broadens (oxygen isotopes, Lu-Hf), the ability to evaluate mobility in radiogenic systems other than U-Pb becomes more important. Low concentrations of many trace elements in zircon make them sensitive recorders of post-crystallization isotopic exchange, but their behavior is poorly understood. Comparison of the Sr- and Nd-isotopic systematics of zircon and its host rock can be used to evaluate the retentivity of zircon for the isotopes of these elements . We examined zircon populations from granitoids ranging in age from 100 Ma to 3.7 Ga. Zircon populations were dated via SHRIMP and both multigrain zircon separates and whole rock powders were analyzed for trace element concentrations, 87Sr/86Sr and 143Nd/144Nd. Analyses of other mineral separates (feldspar, apatite) allow the construction of whole- rock mineral isochrons. In each sample the zircons display disturbance in both the Rb-Sr and Sm-Nd systems. In fact, when compared to the all the other minerals represented on the isochron, the zircons display the highest amount of discordance. Likely promoted by radiation damage, the degree of open-system behavior of the Rb-Sr and Sm-Nd systems increases with the age of the samples. With greatly increased effective diffusivities and trace element mobility, general acceptance of zircons as impervious isotopic time capsules should be regarded with caution.

Weaver, K. L.; Depaolo, D. J.

2007-12-01

203

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

204

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

205

Ti site occupancy in zircon  

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

206

Future Exploration of Titan  

NASA Astrophysics Data System (ADS)

Titan promises to be the Mars of the Outer Solar System - the focus of not only the broadest range of investigations in planetary science but also the focus of public attention. The reasons for exploring Titan are threefold: 1. Titan and Astrobiology : Titan ranks with Mars and Europa as a prime body for astrobiological study due to its abundant organics. Like Europa, it may well have a liquid water interior. 2. Titan - A world in its own right. Titan deserves study even only to put other satellites (its remarkably smaller Saturnian siblings, and its same-sized but volatile-poor Jovian counterparts) in context. The added dimension of an atmosphere makes Titan's origin and evolution particularly interesting. 3. Titan - an environmental laboratory for Earth. Titan will be an unrivalled place to investigate meteorological, oceanographical and other processes. Many of these (e.g. wave generation by wind) are only empirically parameterized - the very different physical parameters of the Titan environment will bring new insights to these phenomena. While Cassini-Huygens will dramatically boost our knowledge of Titan, it will likely only whet our appetite for more. The potential for prebiotic materials at various locations (in particular where liquid water has interacted with photochemical deposits) and the need to monitor Titan's meteorology favor future missions that may exploit Titan's unique thick-atmosphere, low-gravity environment - a mobile platform like an airship or helicopter, able to explore on global scales, but access the surface for in-situ chemical analysis and probe the interior by electromagnetic and seismic means. Such missions have dramatic potential to capture the public's imagination, on both sides of the Atlantic.

Lorenz, R. D.; Titan Decadal Panel Collaboration

2001-11-01

207

Finite element modeling of perforated PZT-polymer compositest  

Microsoft Academic Search

Perforated PZT-polymer composites with 3–1 connectivity patterns have been fabricated by drilling square holes perpendicular to the poling direction in prepoled PZT blocks and filling the holes with epoxy polymer. The influence of the separation between the holes on the dielectric and piezoelectric properties of the composite was studied. The finite element method has been used to calculate the stress

S. Davanzo; A. Safari; R. E. Newnham

1985-01-01

208

Pneumatic flow control valve using particle excitation by PZT transducer  

Microsoft Academic Search

This paper reports a flow control valve for pneumatic actuators. This flow control valve has a lightweight and simple structure using particle excitation by PZT transducer, which is driven at resonance mode and it can be used as a variable speed controller for pneumatic actuators. A PZT transducer has been used for controlling flow rate in this study. The flow

Daisuke Hirooka; Koichi Suzumori; Takefumi Kanda

2009-01-01

209

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.

210

Titan from Cassini  

Microsoft Academic Search

Saturn's largest moon Titan is sometimes touted as the most Earth-like body in our solar system. Not only does it have a thick, nitrogen-dominated atmosphere featuring photochemical hazes, clouds and precipitation (where methane plays a similar role in Titan's atmosphere as water vapor does in Earth's), but also a surface that shows mountains, tectonic structures, impact craters, lakes, seas, river

Robert H. Brown; Christophe Sotin

2010-01-01

211

Is Titan Partially Differentiated?  

Microsoft Academic Search

The recent measurement of the gravity coefficients from the Radio Doppler data of the Cassini spacecraft has improved our knowledge of the interior structure of Titan (Rappaport et al. 2008 AGU, P21A-1343). The measured gravity field of Titan is dominated by near hydrostatic quadrupole components. We have used the measured gravitational coefficients, thermal models and the hydrostatic equilibrium theory to

G. Mitri; R. T. Pappalardo; D. J. Stevenson

2009-01-01

212

Stabilized Aluminum Titanate  

NASA Technical Reports Server (NTRS)

Stable, potentially-inexpensive, cubic crystalline alpha aluminum titanate that shows no phase change to 1,700 K used in heat exchangers. Particular stabilizing species must be selected with careful attention to crystal dimensions and bond angles of alpha and beta phases of aluminum titanate.

Schroeder, J. E.

1985-01-01

213

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

NASA Astrophysics Data System (ADS)

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

Adams, Laurence J.

1990-10-01

214

The astrobiology of Titan  

NASA Astrophysics Data System (ADS)

Largest satellite of Saturn and the only satellite in the solar system having a dense atmosphere, Titan is one of the key planetary bodies for astrobiological studies, due to several aspects: Its analogies with planet Earth, in spite of much lower temperatures, The Cassini-Huygens data have largely confirmed the many analogies between Titan and our own planet. Both have similar vertical temperature profiles, (although much colder, of course, on Titan). Both have condensable and non condensable greenhouse gases in their atmosphere. Both are geologically very active. Furthermore, the data also suggest strongly the presence of a methane cycle on Titan analogous to the water cycle on Earth. The presence of an active organic chemistry, involving several of the key compounds of prebiotic chemistry. The recent data obtained from the Huygens instruments show that the organic matter in Titan low atmosphere (stratosphere and troposphere) is mainly concentrated in the aerosol particles. Because of the vertical temperature profile in this part of the atmosphere, most of the volatile organics are probably mainly condensed on the aerosol particles. The nucleus of these particles seems to be made of complex macromolecular organic matter, well mimicked in the laboratory by the "Titan's tholins". Now, laboratory tholins are known to release many organic compounds of biological interest, such as amino acids and purine and pyrimidine bases, when they are in contact with liquid water. Such hydrolysis may have occurred on the surface of Titan, in the bodies of liquid water which episodically may form on Titan's surface from meteoritic and cometary impacts. The formation of biologically interesting compounds may also occur in the deep water ocean, from the hydrolysis of complex organic material included in the chrondritic matter accreted during the formation of Titan. The possible emergence and persistence of Life on Titan 1 All ingredients which seems necessary for Life are present on Titan : • liquid water : permanently as a deep sub-surface ocean, and even episodically on the surface, • organic matter : in the internal structure, from chondritic materials, and in the atmosphere and on the surface, from the atmospheric organic chemistry • and energy : in the atmosphere (solar UV photons, energetic electrons from Saturn magnetosphere and cosmic rays) and, probably, in the environment of the sub-surface ocean (radioactive nuclei in the deep interior and tidal energy dissipation) as also supported by the likely presence of cryovolcanism on the surface Thus, it cannot be excluded that life may have emerged on or in Titan. In spite of the extreme conditions in this environment life may have been able to adapt and to persist. Many data are still expected from the Cassini-Huygens mission and future astrobiological exploration mission of Titan are now under consideration. Nevertheless, Titan already looks like another word, with an active prebiotic-like chemistry, but in the absence of permanent liquid water, on the surface: a natural laboratory for prebiotic-like chemistry. References. Fortes, A.D. (2000), `Exobiological implications of a possible ammonia-water ocean inside Titan', Icarus 146, 444-452 Raulin, F. (2005), `Exo-Astrobiological Aspects of Europa and Titan: From Observations to Speculations', Space Science Review 116 (1-2), 471-496. Nature, (2005), `The Huygens probe on Titan', 8 News & Views, Articles and Letters 438, 756-802 Schulze-Makuch, D., and Grinspoon D.H. (2005), `Biologically enhanced energy and carbon cycling on Titan?',Astrobiology 5, 560-567. 2

Raulin, F.; Coll, P.; Cabane, M.; Hebrard, E.; Israel, G.; Nguyen, M.-J.; Szopa, C.; Gpcos Team

215

ISO Spectroscopy of Titan  

NASA Astrophysics Data System (ADS)

In the spectroscopic mode, Titan was observed by ISO in 1997 by SWS/Grating, PHT-S and CAM/CVF. The combination of these data provides Titan's spectrum from 5 to 17 and from 2.5 to 5 ?m with resolving powers ranging from 40 (CAM/CVF) to 2000 (SWS). The analysis of the spectra provides information on (a) Titan's atmospheric structure (temperature and composition) and (b) Titan's surface (through the emission observed in the 2.9-micron window). In this paper we concentrate on the 7 to 9 and 2.5 to 5 micron regions. A temperature profile for Titan's disk is inferred from the analysis of the 7.7 ?m CH4 band. The CH3D abundance is estimated to be 7.5 (+4.0-3.7) × 10-6, for a D/H ratio of 9.5 (+9.5-1.0) × 10-5. The 2.9 methane ``window'' on Titan is observed in its full shape for the first time. It shows two peaks at 2.7 and 2.8 ?m, and an absorption feature at 2.75 ?m, which may be the spectral signature of a surface component on Titan.

Coustenis, A.; Salama, A.; Lellouch, E.; Encrenaz, Th.; Schulz, B.; Feuchtgruber, H.; Gautier, D.; Ott, S.; de Graauw, Th.; Kessler, M. F.

2000-11-01

216

Surface-modified lead-zirconium-titanate system for solution-processed ferroelectric-gate thin-film transistors  

NASA Astrophysics Data System (ADS)

We propose the use of a La2O3 (LO) film as the capping layer for improvement of a semiconductor/insulator interface in a solution-processed indium-tin-oxide (ITO) ferroelectric-gate thin-film transistor (FGT) device. It is demonstrated that the LO layer acts as a good barrier film not only for preventing the interdiffusion between the ITO semiconductor and lead-zirconium-titanate (PZT) insulator layers, but also for stabilizing the PZT surface structure. The fabricated FGT device exhibited high I on/ I off, large M w, high ? FE and improved retention time of about 109, 3.5 V, 7.94 cm2 V-1 s-1 and 1 day, respectively, which are comparable to or better than those obtained with FGTs fabricated by means of conventional vacuum processes. We also point out that the key origin of the interface improvement is likely due to the incorporation of La into the PZT system, forming a La surface-modified PZT system which is more stable than the pure PZT in terms of Pb volatility and formation of oxygen vacancies.

Phan, Tue Trong; Miyasako, Takaaki; Higashimine, Koichi; Tokumitsu, Eisuke; Shimoda, Tatsuya

2013-11-01

217

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

218

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

219

Crystallization thermometers for zircon and rutile  

Microsoft Academic Search

Zircon and rutile are common accessory minerals whose essential structural constituents, Zr, Ti, and Si can replace one another to a limited extent. Here we present the combined results of high pressure–temperature experiments and analyses of natural zircons and rutile crystals that reveal systematic changes with temperature in the uptake of Ti in zircon and Zr in rutile. Detailed calibrations

E. B. Watson; D. A. Wark; J. B. Thomas

2006-01-01

220

Titan Casts Revealing Shadow  

NASA Astrophysics Data System (ADS)

A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in diameter, which corresponds to the size of a dime as viewed from about two and a half miles. Illustration of Crab, Titan's Shadow and Chandra Illustration of Crab, Titan's Shadow and Chandra Unlike almost all of Chandra's images which are made by focusing X-ray emission from cosmic sources, Titan's X-ray shadow image was produced in a manner similar to a medical X-ray. That is, an X-ray source (the Crab Nebula) is used to make a shadow image (Titan and its atmosphere) that is recorded on film (Chandra's ACIS detector). Titan's atmosphere, which is about 95% nitrogen and 5% methane, has a pressure near the surface that is one and a half times the Earth's sea level pressure. Voyager I spacecraft measured the structure of Titan's atmosphere at heights below about 300 miles (500 kilometers), and above 600 miles (1000 kilometers). Until the Chandra observations, however, no measurements existed at heights in the range between 300 and 600 miles. Understanding the extent of Titan's atmosphere is important for the planners of the Cassini-Huygens mission. The Cassini-Huygens spacecraft will reach Saturn in July of this year to begin a four-year tour of Saturn, its rings and its moons. The tour will include close flybys of Titan that will take Cassini as close as 600 miles, and the launching of the Huygens probe that will land on Titan's surface. Chandra's X-ray Shadow of Titan Chandra's X-ray Shadow of Titan "If Titan's atmosphere has really expanded, the trajectory may have to be changed." said Tsunemi. The paper on these results has been accepted and is expected to appear in a June 2004 issue of The Astrophysical Journal. Other members of the research team were Haroyoski Katayama (Osaka University), David Burrows and Gordon Garmine (Penn State University), and Albert Metzger (JPL). Chandra observed Titan from 9:04 to 18:46 UT on January 5, 2003, using its Advanced CCD Imaging Spectrometer instrument. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters,

2004-05-01

221

The Astrobiology of Titan  

NASA Astrophysics Data System (ADS)

Titan is a target of astrobiological interest because of its thick atmosphere, ample organics inventory, large size and presence of water ice and rock. Multiple habitable environments, or prebiotically interesting environments, may exist.

Lunine, J. I.

2014-02-01

222

The greenhouse of Titan.  

NASA Technical Reports Server (NTRS)

Analysis of non-gray radiative equilibrium and gray convective equilibrium on Titan suggests that a massive molecular-hydrogen greenhouse effect may be responsible for the disagreement between the observed IR temperatures and the equilibrium temperature of an atmosphereless Titan. Calculations of convection indicate a probable minimum optical depth of 14 which corresponds to a molecular hydrogen shell of substantial thickness with total pressures of about 0.1 bar. It is suggested that there is an equilibrium between outgassing and blow-off on the one hand and accretion from the protons trapped in a hypothetical Saturnian magnetic field on the other, in the present atmosphere of Titan. It is believed that an outgassing equivalent to the volatilization of a few kilometers of subsurface ice is required to maintain the present blow-off rate without compensation for all geological time. The presence of an extensive hydrogen corona around Titan is postulated, with surface temperatures up to 200 K.

Sagan, C.

1973-01-01

223

Titan - Some new results  

SciTech Connect

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. 21 refs.

Owen, T.; Gautier, D.

1989-01-01

224

ALMA observations of Titan  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

225

Fabrication and structural characterization of a resonant frequency PZT microcantilever  

NASA Astrophysics Data System (ADS)

The fabrication and structural characterization of a surface micromachined, resonant frequency, Pb(Zr, Ti)O3 (PZT) microcantilever will be presented. The PZT microcantilever was fabricated using surface micromachining techniques, and used a low-stress silicon nitride thin film as the base material for the microcantilever onto which a PZT thin film was incorporated. The PZT thin film is used as both the microsensor and the microactuator. A unique fabrication procedure was developed in order to eliminate the step of encapsulating the PZT during the removal of the spacer layer. The encapsulation step was avoided because of the difficulty in finding a suitable material, which would protect the PZT during the removal of the spacer layer yet not affect its material properties. This predicament was resolved by removing the spacer layer prior to the deposition of the PZT. The microcantilevers were characterized extensively using an atomic force microscope in an unusual manner. The atomic force microscope was modified in such a fashion that the deflection at the tip of the microcantilever could be measured as the frequency of an electrical signal applied to the PZT thin film was varied. In addition, an impedance analyzer was used to characterize the microcantilevers. Simple thin-film, laminated plate theory was used to obtain a closed-form solution for the modal response of the microcantilever, while ANSYS was used to obtain modal and harmonic simulation results. It will be shown that the experimental, numerical, and theoretical modal results are within +/-10% of one another. The experimental and numerical harmonic results differ by an order of magnitude; however, the numerical model is currently being modified to more accurately represent the PZT microcantilever. From the information gathered during the structural characterization of the PZT microcantilever, it will be shown that certain higher-order resonant frequency modes have very large mechanical responses. These higher-order resonant frequency modes give designers another parameter to adjust when trying to optimize the design of their resonant frequency device.

Zurn, S.; Hsieh, M.; Smith, G.; Markus, D.; Zang, M.; Hughes, G.; Nam, Y.; Arik, M.; Polla, D.

2001-04-01

226

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

227

Phase correction in piezoelectric photoacoustic Fourier transform infrared spectroscopy of mica  

Microsoft Academic Search

Piezoelectric photoacoustic IR spectra of mica are obtained using a Fourier transform IR spectrometer and lead zirconate titanate (PZT) as a detector. The spectra exhibit negative intensities and transmission like bands, instead of more conventional absorption bands generally observed with a gas- microphone cell. Correct spectra of mica\\/PZT are calculated only when the interferogram phase is constrained to the first

S. L. Zhang; Kirk H. Michaelian; James A. Burt

1997-01-01

228

Titan’s atmosphere from ISO mid-infrared spectroscopy  

Microsoft Academic Search

We have analyzed Titan observations performed by the Infrared Space Observatory (ISO) in the range 7–30 ?m. The spectra obtained by three of the instruments on board the mission (the short wavelength spectrometer, the photometer, and the camera) were combined to provide new and more precise thermal and compositional knowledge of Titan’s stratosphere. With the high spectral resolution achieved by

Athena Coustenis; A. Salama; B. Schulz; S. Ott; E. Lellouch; T. h Encrenaz; D. Gautier; H. Feuchtgruber

2003-01-01

229

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

230

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

231

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

232

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

233

Flexible PZT thin film tactile sensor for biomedical monitoring.  

PubMed

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 ?m on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g. PMID:23698262

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-01-01

234

An efficient drive, sensing, and actuation system using PZT stack actuator cells  

E-print Network

The PZT cellular actuator developed in the MIT d'Arbeloff Laboratory utilizes small-strain, high-force PZT stack actuators in a mechanical flexure system to produce a larger-strain, lower-force actuator useful in robotic ...

Barragán, Patrick R

2012-01-01

235

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

236

Characteristics of zircon suitable for REE extraction  

NASA Astrophysics Data System (ADS)

Zircons (ZrSiO4) from Naegi and Ohro granitic pegmatites, Japan and from Saigon alkaline basalt, Vietnam, were mineralogically characterized by inductively couples plasma mass spectrometry (ICP-MS), electron-microprobe analysis (EMPA), X-ray powder diffraction, micro-Raman spectroscopy and leaching experiment. The powder XRD and Raman spectra analyses show that the degree of crystallinity decreases from Saigon, to Ohro and Naegi zircons. Quantitative analytical results by the EMPA indicate that the Naegi and Ohro zircon samples contain a large amount of REE2O3, while REE contents in Saigon zircon are below detection limit. The leaching experiments for the present zircons under the condition of a solvent 1M-HCl, at a room temperature to 250 °C and retention time of 30h resulted in about 100 %, 50 % and 1 % recoveries of REE from the Naegi, Ohro and Saigon zircons, respectively. Leaching experiments for the Naegi zircon under the condition of a solvent 1N-HCl, heating temperature of 50 °C, 100 °C, 150 °C and 200 °C, and retention time 30h, showed that a significant amount of REE was leached out at a temperature above 150 °C. However, the leaching experiments of the Naegi and Ohro zircons at room temperature (about 25 °C) show that REE were hard to be leached. These results indicates that both low crystallinity of zircon and higher leaching temperature are requisite for effective leaching of REE from zircon.

Watanabe, Y.; Hoshino, M.

2011-12-01

237

Zircon Saturation Re-Revisited  

NASA Astrophysics Data System (ADS)

Zircon saturation in silicate melts has been utilized for magma thermometry and predicting the survival of zircon xenocrysts in crustal melts for nearly 30 years. The original calibration, which assumed only compositional (M = [2Ca+Na+K]/[AlxSi]) and temperature controls, was bolstered by subsequent experimental investigations and thermometry of volcanic rocks and glasses. These latter studies, while confirming the general predictions of the model, suggested that other environmental parameters (e.g., pressure, H 2O, halogens, [Fe], oxygen fugacity, etc.) might have second-order effects. Given the tremendous advances in micro-analytical capabilities over the intervening three decades, we have returned to this question with a view to obtaining a refined zircon solubility calibration as a function of P, T, [H2O] and FM (= [Na+K+2(Ca+Mg+Fe)]/[AlxSi]). Detailed SEM imaging of the original low-temperature crystallization experiments (1.2-2.1 kbar) revealed limitations of this approach and we chose instead to use a new experimental design in which shattered Mud Tank zircon is infiltrated by melts of selected composition and water contents. 10 kbar hydrothermal experiments (925o and 850oC) were run for sufficiently long durations (2 to 3 days) to ensure microscale diffusive equilibration of Zr released by zircon dissolution into the intercrystalline melt pools. Sectioned run products were analyzed by SIMS ion imaging of selected areas where glass is exposed in close proximity to or surrounded by Mud Tank zircon fragments. Ion imaging has the advantage of permitting high spatial resolution (3 ?m) analysis of the glasses allowing assessment of Zr equilibration. Using synthetic glass standards, we found [Zr] in anhydrous glasses to be enhanced by ca. 20% relative to hydrous (at 6 wt.% H2O). Our new experiments and re-analysis of the earlier glasses broadly reproduce the original calibration, albeit with substantially enhanced (factor of five) precision compared to the original EMPA analyses. Thus it appears that no significant pressure effect exists up to at least 10 kbar. Ongoing work will expand the pressure range beyond this limit and explore a greater compositional space than previously constrained.

Boehnke, P.; Trail, D.; Schmitt, A. K.; Watson, E. B.; Harrison, M.

2011-12-01

238

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

239

STUDY OF PROTON EXCHANGE MEMBRANE FUEL CELLS (PZT-PEMFCS) WITH NOZZLE AND DIFFUSER  

Microsoft Academic Search

Previous theoretical studies have shown that piezoelectric proton exchange membrane fuel cells (PZT-PEMFCs) might solve water flooding problems and increase cell performance. The innovative design of PZT-PEMFCs results in more oxygen being compressed into the catalyst layer. This enhances the electrochemical reaction and the current density, especially at a high PZT vibration frequency (64 Hz). In this investigation, a single,

Hsiao-Kang Ma; Shih-Han Huang; Ya-Ting Cheng; Chrung Guang Hou

2009-01-01

240

Damping of bending waves in truss beams by electrical transmission lines with PZT actuators  

E-print Network

Damping of bending waves in truss beams by electrical transmission lines with PZT actuators F. dell of the truss beam with an electrical transmission line by a line distribution of PZT actuators. It has been modular beams by coupling them with fourth-order electric transmission lines and adding PZT actu- ators

Boyer, Edmond

241

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

242

Inelastic neutron scattering from zircon  

SciTech Connect

A lattice dynamical investigation of zircon (ZrSiO{sub 4}) has been carried out to obtain a microscopic understanding of its thermodynamic properties, as well as to examine possible soft modes that may contribute to the phase transformation to scheelite type under high pressure. We have measured the neutron weighted phonon density of states of zircon from a polycrystalline sample. The neutron spectra reveal one-phonon excitations extending to 1130 cm{sup -1}, with phonon bands centered at 226, 298, 363, 540, 661, 726, 945, and 1081 cm{sup -1}. A quantitative analysis of the neutron results was carried out using a lattice dynamical rigid-ion model. 4 refs., 3 figs.

Nipko, J.C.; Loong, C.K.

1997-07-14

243

Ti in zircon from the Boggy Plain zoned pluton: implications for zircon petrology and Hadean tectonics  

Microsoft Academic Search

The understanding of zircon crystallization, and of the Ti-in-zircon thermometer, has been enhanced by Ti concentration measurements of zircon from a small, concentrically zoned pluton in south-eastern Australia, the Boggy Plain zoned pluton (BPZP). Zircon crystals from rocks ranging in composition from gabbro to aplite were analysed for U-Th-Pb dating and Ti concentrations by an ion microprobe. Geochronological data yield

R. B. Ickert; I. S. Williams; D. Wyborn

2011-01-01

244

Ti in zircon from the Boggy Plain zoned pluton: implications for zircon petrology and Hadean tectonics  

Microsoft Academic Search

The understanding of zircon crystallization, and of the Ti-in-zircon thermometer, has been enhanced by Ti concentration measurements\\u000a of zircon from a small, concentrically zoned pluton in south-eastern Australia, the Boggy Plain zoned pluton (BPZP). Zircon\\u000a crystals from rocks ranging in composition from gabbro to aplite were analysed for U–Th–Pb dating and Ti concentrations by\\u000a an ion microprobe. Geochronological data yield

R. B. Ickert; I. S. Williams; D. Wyborn

2011-01-01

245

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

246

Anatomy of a low temperature zircon outgrowth  

Microsoft Academic Search

Outgrowths of zircon and xenotime are abundant on detrital zircon in a greenschist facies regional metamorphic slate from\\u000a the Scottish Highlands. Back-scattered electron images reveal that ca. 3-?m wide zircon outgrowths are porous, inclusion-rich\\u000a and contain fine-grained intergrowths with xenotime. Focused ion beam milling, transmission electron microscopy and low-voltage\\u000a scanning transmission electron microscopy show that the outgrowth microstructure is complex,

Duncan C. Hay; Tim J. Dempster; Martin R. Lee; David J. Brown

2010-01-01

247

Titan Pride Center Student Engagement Report  

E-print Network

Titan Pride Center Student Engagement Report FY 2012-2013 Mission Statement The vision of the Titan Pride Center is to instill Titan Pride into all Cal State Fullerton students by connecting them a Titan. Program Overview The core services of the Titan Pride Center include being a campus history

de Lijser, Peter

248

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

Microsoft Academic Search

In this study, the first matrix cracking behavior and creep behavior of zircon matrix silicon carbide fiber composites were studied, together with the fracture and creep behavior of the monolithic zircon. These behaviors are of engineering and scientific importance, and the study was aimed at understanding the deformation mechanisms at elevated temperatures. The first matrix cracking behavior of zircon matrix

Umashankar Anandakumar

2000-01-01

249

Clash of the Titans  

NSDL National Science Digital Library

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 t

Subramaniam, Karthigeyan

2010-01-01

250

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

251

The lakes of Titan  

NASA Astrophysics Data System (ADS)

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.

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

252

ORNL debuts Titan supercomputer  

E-print Network

--by employing a family of processors called graphic processing units first created for computer gaming. Titan in science and technology. The Cray XK7 system contains 18,688 nodes, with each holding a 16-core AMD Opteron year will come from the Department of Energy's Innovative and Novel Computational Impact on Theory

Pennycook, Steve

253

Titan after Cassini Huygens  

Microsoft Academic Search

In 2005, the Huygens Probe gave us a snapshot of a world tantalizingly like our own, yet frozen in its evolution on the threshold of life. The descent under parachute, like that of Huygens in 2005, is happening again, but this time in the Saturn-cast twilight of winter in Titan's northern reaches. With a pop, the parachute is released, and

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

2008-01-01

254

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

255

Methane rain on Titan  

Microsoft Academic Search

The atmosphere of Titan is characterized by means of model computations based on Voyager IRIS IR spectra and published data from laboratory determinations of absorption coefficients and cloud refractive indices. The results are presented in tables and graphs, and it is pointed out that the presence of Ar is not required in the model. Particular attention is given to the

O. B. Toon; C. P. Mckay; R. Courtin; T. P. Ackerman

1988-01-01

256

The lakes of Titan  

Microsoft Academic Search

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

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

2007-01-01

257

Titan from Cassini  

NASA Astrophysics Data System (ADS)

Saturn's largest moon Titan is sometimes touted as the most Earth-like body in our solar system. Not only does it have a thick, nitrogen-dominated atmosphere featuring photochemical hazes, clouds and precipitation (where methane plays a similar role in Titan's atmosphere as water vapor does in Earth's), but also a surface that shows mountains, tectonic structures, impact craters, lakes, seas, river channels and deltas, large deserts with extensive dune fields, and volcanoes. Though these structures and processes appear similar to those of Earth, the whole dance is conducted at 9 astronomical units from the Sun, where a balmy, summer day on Titan is only 95 K, the lakes and seas are filled with liquid hydrocarbons, the bedrock is composed of water ice, the surface is covered with a thick layer of complex organics and nitriles, volcanoes have effused 170K ammonia-methane-water lavas onto the surface, and the dune fields are comprised of sand that's not dramatically different in composition from terrestrial smog. This talk will explore some of what has been learned about Titan's surface and atmosphere during Cassini's roughly 6-year tenure in orbit around Saturn.

Brown, Robert H.; Sotin, Christophe

258

Propane on Titan  

E-print Network

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

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

2003-09-23

259

Your Impact. Titan Pride?  

E-print Network

-athletes with gifts to the Titan Athletics Fund or a specific sport or program. Others decide to turn their passion of tangible benefits afforded to those members giving at specified levels. While these benefits can benefits ensures more dollars are available to the program you designate. Donor recognition is granted

de Lijser, Peter

260

High sensitivity ultrasonic sensor for hydrophone applications, using an epitaxial Pb(Zr,Ti)O 3 film grown on SrRuO 3\\/Pt\\/?-Al 2O 3\\/Si  

Microsoft Academic Search

A piezoelectric ultrasonic sensor has been fabricated using an epitaxial lead zirconate titanate, Pb(Zrx, Ti1?x)O3 (PZT) thin film, grown on an epitaxial SrRuO3\\/Pt\\/?-Al2O3\\/Si substrate. The 3-?m thick PZT film was prepared by the sol–gel method. This sensor structure was very stable during the fabrication process after preparation of the PZT. The fabricated sensor offers a reception sensitivity of up to

M. Ito; N. Okada; M. Takabe; M. Otonari; D. Akai; K. Sawada; M. Ishida

2008-01-01

261

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

262

Crystallization of PZT in Porous Alumina Membrane Channels  

Microsoft Academic Search

Composite Pb(Zr,Ti)O3(PZT)\\/alumina nanostructures are fabricated using 2-dimensi- onal porous alumina as a template. Details of pores filling as well as of crystallization are studied by atomic force microscopy and transmission electron microscopy. The presence of a ferroelectric phase is confirmed by optical second harmonic generation experiments.

O. M. Zhigalina; E. D. Mishina; N. E. Sherstyuk; K. A. Vorotilov; V. A. Vasiljev; A. S. Sigov; O. I. Lebedev; Yu. V. Grigoriev; M. P. De Santo; R. Barberi; Th Rasing

2006-01-01

263

Hydrogen induced degradation phenomena of PZT ferroelectric capacitors  

Microsoft Academic Search

During the CMOS process, ferroelectric capacitors show degraded ferroelectric properties due to a process involving hydrogen. When hydrogen diffuses in PZT thin films through noble metal electrodes (such as Pt, Ir), XRD data indicate a change of lattice parameters and XPS spectra exhibit a change in the Pb-O bonding in the crystalline perovskite phase. In particular, the variation of lattice

June-Mo Koo; TaeHo Kini; Jiyoung Kim

2000-01-01

264

Titan Student Centers Introduction and Overview ................................................. Section  

E-print Network

#12;Titan Student Centers Introduction and Overview ................................................. Section Page One One Titan Student Centers 2014-15 Fiscal Year Budget Charts and Tables .............................................................. Section Page Four Two Titan Student Centers 2014-15 Fiscal Year Budget Note Package

de Lijser, Peter

265

A review of Titan’s atmospheric phenomena  

Microsoft Academic Search

Saturn’s satellite Titan is a particularly interesting body in our solar system. It is the only satellite with a dense atmosphere,\\u000a which is primarily made of nitrogen and methane. It harbours an intricate photochemistry, that populates the atmosphere with\\u000a aerosols, but that should deplete irreversibly the methane. The observation that methane is not depleted led to the study\\u000a of Titan’s

Mathieu Hirtzig; Tetsuya Tokano; Sébastien Rodriguez; Stéphane le Mouélic; Christophe Sotin

2009-01-01

266

Modeling Zircon Saturation Within Simulated Impact Events  

NASA Astrophysics Data System (ADS)

Knowledge of the impact flux in the early inner solar system is fundamental to understanding the near surface conditions on the terrestrial planets during this formative period. However the lack of preserved >2.0 Ga craters precludes direct sampling of such events over the first 55% of Earth history. We do, however, have preserved crustal materials in the form of detrital zircons with ages up to 4.38 Ga that can potentially act as environmental monitors. In order to interpret zircon growth features in terms of impact events, such as the Late Heavy Bombardment (LHB), we developed a zircon saturation model that estimates the zircon crystallization temperature spectrum and the fraction of Zr in the continental crust expected to be processed through impact melting. Such modeling results can then be compared to the crystallization temperature spectrum of detrital Hadean zircons to estimate the fraction that were impact-produced. Magmatic zircon growth during an impact event is controlled by ambient temperature, Zr content and composition of the target material, and impact energy. Impacts need to be sufficiently large to permit decompression melting of uplifted middle to upper crust (i.e., low energy bolides will not produce melt sheets and thus impact zircons). We modeled the LHB using the thermal model and hypothesized bolide flux of Abramov and Mojzsis (Nature 459, 419, 2009). Target compositions for modern and Archean crust were estimated from large geochemical databases and selected using a Monte Carlo process by which the full spectrum of compositions were randomly chosen. Model results for impact produced zircon from a target of Archean composition yield a zircon crystallization temperature distribution significantly higher than that observed for detrital Hadean zircons from Western Australia. We take this as evidence that impact produced zircons are not a significant source for this population. Modeled results from impacts on modern crust yield temperatures remarkably similar to Ti-in-zircon crystallization temperatures of recent large impact events (i.e., Morokweng, Manicouagan). Refinements of the model include: reduction of sampling bias in compositional databases and development of hypothetical crustal compositions to simulate Hadean crystallization temperatures. This model can be used as an analog to predict zircon abundance and crystallization temperature spectrum for other planetary bodies (i.e. Moon, Mars, Vesta) where surface compositions are known or estimated. When rocks are in hand, in the form of meteorites or from sample return missions, modeled results can be compared to extracted zircons to estimate the contribution of impacts and provide insights into ancient impact histories.

Wielicki, M. M.; Harrison, M.; Boehnke, P.; Schmitt, A. K.

2011-12-01

267

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

268

Titan's methane cycle in the Titan WRF general circulation model  

NASA Astrophysics Data System (ADS)

Observations of methane clouds, surface lakes and precipitation (or evidence of past precipitation) on Titan allow us to assemble information about the seasonal evolution of Titan’s methane cycle, as well as Titan’s lower atmosphere and near-surface environment in general. Using the TitanWRF general circulation model [Newman et al., 2011] we attempt to reproduce some of these observations by simulating Titan’s atmospheric circulation and methane cycle, assuming limited surface methane and using a simple large-scale cloud scheme both with and without latent heating effects included. We have performed both ‘current’ and ‘reversed perihelion’ simulations, i.e. using the current solar forcing (perihelion in southern summer) and its exact opposite (perihelion in northern summer, as occurred at some time in the past), to test the hypothesis that the timing of perihelion explains the asymmetry in surface methane distribution currently observed. We look at the net transport and latitudinal distribution of surface methane as the simulations tend toward steady state after >100 Titan years. Initially, as the equatorial regions lose and the high latitudes gain significant methane each Titan year, our results are highly sensitive to initial conditions. However, as the simulations tend toward steady state and specifically as the tropics dry out, the ‘current’ and ‘reversed perihelion’ results increasingly tend toward ‘mirror images’ of each other. With the decreased significance of tropical moisture sources, the methane balance becomes dominated by pole-to-pole exchange (inter-polar competition for methane) with the simulations tending toward final states with significantly more high latitude surface methane in the hemisphere with the longer, cooler summer (i.e., in the northern hemisphere for current solar forcing, in line with the asymmetry observed). References: Newman, C. E., et al.: "Stratospheric superrotation in the TitanWRF model". Icarus, Vol. 213, pp. 636-654, 2011.

Newman, C. E.; Lian, Y.; Richardson, M. I.; Lee, C.; Toigo, A. D.

2012-04-01

269

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

270

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

271

Titanic exploration with GIS  

USGS Publications Warehouse

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

Kerski, J.J.

2004-01-01

272

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

273

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

274

NPR: Titanic Baby  

NSDL National Science Digital Library

This Web site contains an audio file of a story broadcast on National Public Radio earlier this month. The broadcast relates the poignant story of a four-year effort to identify the exhumed body of a 13-month-old child who died in the Titanic disaster. A metal medallion buried with the body serendipitously preserved a bit of the wrist bone, from which forensic scientists could extract mitochondrial DNA and eventually find the child's living relatives.

2002-01-01

275

The Lakes of Titan  

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

276

Titan's methane clock  

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

277

Titan after Cassini Huygens  

NASA Astrophysics Data System (ADS)

In 2005, the Huygens Probe gave us a snapshot of a world tantalizingly like our own, yet frozen in its evolution on the threshold of life. The descent under parachute, like that of Huygens in 2005, is happening again, but this time in the Saturn-cast twilight of winter in Titan's northern reaches. With a pop, the parachute is released, and then a muffled splash signals the beginning of the first floating exploration of an extraterrestrial sea-this one not of water but of liquid hydrocarbons. Meanwhile, thousands of miles away, a hot air balloon, a "montgolfiere," cruises 6 miles above sunnier terrain, imaging vistas of dunes, river channels, mountains and valleys carved in water ice, and probing the subsurface for vast quantities of "missing" methane and ethane that might be hidden within a porous icy crust. Balloon and floater return their data to a Titan Orbiter equipped to strip away Titan's mysteries with imaging, radar profiling, and atmospheric sampling, much more powerful and more complete than Cassini was capable of. This spacecraft, preparing to enter a circular orbit around Saturn's cloud-shrouded giant moon, has just completed a series of flybys of Enceladus, a tiny but active world with plumes that blow water and organics from the interior into space. Specialized instruments on the orbiter were able to analyze these plumes directly during the flybys. Titan and Enceladus could hardly seem more different, and yet they are linked by their origin in the Saturn system, by a magnetosphere that sweeps up mass and delivers energy, and by the possibility that one or both worlds harbor life. It is the goal of the NASA/ESA Titan Saturn System Mission (TSSM) to explore and investigate these exotic and inviting worlds, to understand their natures and assess the possibilities of habitability in this system so distant from our home world. Orbiting, landing, and ballooning at Titan represent a new and exciting approach to planetary exploration. The TSSM mission architecture inherently provides the optimal balance between science, risk, and cost using three guiding principles: Achieve science well beyond the high bar set by Cassini Huygens. The TSSM orbiter, lander, and balloon have been configured with instruments and operational concept that go well beyond Cassini-Huygens capabilities, thus ensuring dramatic remote observation and in situ science discoveries. Build upon successful design and operational experience and lessons learned. ESA has successful experience in designing and landing probes on Titan (Huygens), as does NASA in implementing an orbiter at Saturn (Cassini). Long life design rules and extensive operational experience in the Saturn system have been applied to form the TSSM concept. Lessons learned from Galileo, Cassini, New Horizons, and MRO have been applied to reduce risk and lower cost. Development by ESA of the montgolfiere combines prior experience with Earth and planetary balloon systems to enable innovative science and unprecedented mobility for surface exploration. Strong international partnership. TSSM represents a collaborative effort between NASA and ESA that is structured to provide the best possible mission at a reasonable cost to NASA and to ESA. This NASA-ESA partnership leverages resources to maximize science return, distribute risk, and ensure technical readiness.

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

2008-12-01

278

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

279

Titan's Methane Cycle is Closed  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

280

Zircon dating of oceanic crustal accretion.  

PubMed

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

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

2009-02-20

281

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

282

Thick film sol gel PZT transducer using dip coating  

Microsoft Academic Search

A sol gel process has been used to develop a 30 ?m thick PZT coating on a sapphire wafer. The sol gel film was removed and plated with platinum electrodes. The free-standing film had a free dielectric constant (?T) of 820, a thickness-mode coupling coefficient (kt) of 0.17, a speed of sound (c) of 3700 m\\/s, and an acoustic impedance

Kenneth L. Gentry; Jason M. Zara; Sang-Don Bu; Chang-Beom Eom; Stephen W. Smith

2000-01-01

283

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2009-2010 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

284

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2008-2009 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

285

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2010-2011 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force (TTF) functions

de Lijser, Peter

286

Titan Parents Association Scholarship Spring 2012  

E-print Network

Titan Parents Association Scholarship Spring 2012 Amount: $500 Established by: Titan Parents Association This program was established by the Cal State Fullerton Titan Parents Association. Scholarship campaigns and Titan Parents programs and events. Funds must be used for the upcoming academic semester

de Lijser, Peter

287

Titan Tusk Force Student Engagement Report  

E-print Network

Titan Tusk Force Student Engagement Report FY 2012-2013 Mission Statement The mission of Titan Tusk Force is to develop a strong sense of campus unity, pride and identity with CSUF. Titan Tusk Force, CSUF, Incorporated here at California State University, Fullerton. Program Overview Titan Tusk Force

de Lijser, Peter

288

Fabrication of 1-3 piezo-composites using new micro PZT fibers  

Microsoft Academic Search

This paper presents a novel fabrication method of PZT micro-fibers using activated carbon template with the aim of manufacturing PZT\\/epoxy 1-3 composites. Porous carbon was first prepared by chemical activation technology. The pore diameter formed in an activated carbon template is of several microns and lengths are up to several millimeters. These pores provide a basic platform to grow PZT

Caifeng Chen; Jun Liu; Xiaoning Jiang; Ying Luo; Fuh-Gwo Yuan; Xiaoli Han; Jinjin Liao

2011-01-01

289

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

290

Titan's atmosphere from DISR  

NASA Astrophysics Data System (ADS)

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

West, Robert

291

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

Alpay, S. Pamir

292

Zinc titanate sorbents  

DOEpatents

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

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

1998-01-01

293

Zinc titanate sorbents  

DOEpatents

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

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

1998-02-03

294

Hydrothermal synthesis of sodium bismuth titanate and titanate nanofibers  

NASA Astrophysics Data System (ADS)

A hydrothermal processing method was developed for the synthesis of sodium bismuth titanate powders and thin films from suitable precursors at 150°C. Oxide precursors were best suited for preparing pure phase materials. The sodium bismuth titanate powders consisted of cube shaped crystals. A modified solution-reprecitation model involving partial dissolution of the precursors was proposed to explain the growth of these particles. The thin films were prepared on strontium titanate (100) substrate. A sample holder was specially designed and fabricated to secure the substrates in the reaction vessel. The result was a relatively smooth film of thickness ?550 nm. The films were essentially single crystalline and had strong epitaxial relationship with the substrate. Titanate nanofibers (NaxH yTinO2n+1° zH2O) were known to form under similar hydrothermal conditions as sodium bismuth titanate powders. Detail research revealed that the pure hydroxide and oxide precursors tend to form sodium bismuth titanate powders or thin films. Titanate nanofibers were the predominant product when any other ions or organics were present in the precursor. Much faster reaction kinetics for the formation of nanofibers was observed when certain organic compounds were added deliberately with the precursors. Accordingly, a hydrothermal process was developed for converting the precursors to titanate nanofibers in a significantly shorter time than reported in the literature. A thin film consisting of vertically aligned nanofibers was prepared on titanium substrate at 150°C in as little as 30 minutes. Complete conversion of starting precursors to free standing nanofibers was achieved in ˜8 hours at 150°C. The as-prepared nanofibers were some form of sodium titanate. They were converted to hydrogen titanate by ion exchange. Differential Scanning calorimetric experiments were performed to understand the thermal evolution of the fibers. The hydrogen titanate fibers underwent structural modifications even at temperatures less than 100°C. Research was done to understand the structure of these hydrogen titanate nanofibers with the aid of HRTEM, simulation of HRTEM images and x-ray diffraction. Initial results revealed that the fibers observed under the microscope had either a lepidocrocite type structure or an anatase type structure.

Kundu, Animesh

295

Titan's astrobiology: some new data  

NASA Astrophysics Data System (ADS)

The Cassini-Huygens observations of Titan have strongly strengthened its astrobiological impor-tance, clearly showing that Titan is one of the key planetary bodies for astrobiological studies. Indeed the Cassini-Huygens data show that there are many similarities which can be found when comparing Titan and the early Earth, in spite of much lower temperatures for Titan. One of these similarities is the presence of an active and complex organic chemistry in Titan's environment, which occurs from the high atmosphere to the surface and very likely in the sub-surface. This organic chemistry involves several of the key compounds of terrestrial prebiotic chemistry, and it represents, by itself, a major astrobiological aspect of Titan. Moreover, the potential presence of an internal water-ocean makes Titan a potential habitable environment, of obvious astrobiological importance. In fact, after five years of close observation by remote sensing and in situ instrumentations from the Cassini-Huygens mission, Titan does not look any more like a frozen primitive Earth, but it looks like an evolving planet, geologically active, with cryo-volcanism, eolian erosion, clouds and precipitations, and a methane cycle analogous to the water cycle on Earth. But the new data also show that a complex organic chemistry is taking place in the very high atmospheric layers of the satellite, with the formation in the ionosphere of high molecular weight (up about 10 000 Daltons) ions. Are these ions abundant enough in the lower atmosphere zones to act as organic monomers which then grow by aggregation, sedimentation and condensation down to the surface? This is one of the key questions that chemical models have now to answer. Cassini-Huygens observations have shown that there is no large surface ocean on Titan, but large regional lakes which behave like evolving liquid media. Those lakes are probably accumulating complex organics of astrobiological interest, including organic aerosols, and could be a prime astrobiologically oriented target for future exploration of Saturn's largest satellite. Cassini-Huygens has shown that the chemical composition of Titan's aerosols is similar to that of laboratory Titan's tholins. The behavior of those tholins when sub-mitted to high solar UV radiation has recently been studied in Earth orbit. The results show a slight but complex photodegradation in some cases. Moreover, recent laboratory studies of the interaction between Titan's tholins and simulated Titan's surface strongly suggests that many compounds of biological interest, including amino-acids, could be produced on Titan's surface. These new data will be presented together with a general description of Titan's astrobiological aspects as seen from Cassini-Huygens data. References F. Raulin. Astrobiology and habitability of Titan. Space Science Reviews 135, 37-48 (2008) F. Raulin , C. P. McKay , J. I. Lunine and T. Owen. Titan's Astrobiology. In "Titan from Cassini-Huygens" R. Brown, J-P Lebreton H.Waite Eds, Springer, pp. 215-233 (2009) F. Raulin, K. P. Hand, C. P. McKay and M. Viso. Exobiology and planetary protection. In "Moons of the outer solar system: exchange processes involving the interiors", O. Grasset et al. Eds, Space Science Review, in press (Feb. 2010).

Raulin, Francois; Coll, Patrice; Buch, Arnaud; Cloix, Megane; Guan, Yuan Yong; Jerome, Murielle; Poch, Olivier; Ramirez, Sandra I.; Szopa, Cyril; Cottin, Hervé

296

The dynamics of Titan's atmosphere  

NASA Astrophysics Data System (ADS)

Titan is a slow rotator, and its atmospheric zonal winds are cyclostrophic. The most convincing evidence of this comes from temperatures retrieved from Voyager spacecraft infrared observations, and pressure fields inferred from stellar occultations observed from Earth. Titan has a moderate obliquity, comparable to Earth's, and the radiative relaxation times in its stratosphere are sufficiently short that large seasonal modulations of the temperatures and winds are expected. This is in contrast to Venus, the only other body in the solar system that has global cyclostrophic winds. There, seasonal effects are secondary, because its rotation axis is nearly normal to its orbit. Zonal-mean meridional winds on Titan have been inferred from the retrieved atmospheric temperatures and the observed distribution of stratospheric hazes. The winds are sluggish, on the order of centimeters per second in the stratosphere, in part because of the long radiative time constants. The stratospheric temperatures suggest that the meridional circulation may be thermally indirect. On Earth, this often results from circulations being driven and/or modulated by vertically propagating waves. However, atmospheric waves on Titan are as yet poorly characterized. Titan may have an analog to the terrestrial Antarctic ozone hole: Voyager spacecraft observations of Titan indicated cold temperatures, strong circumpolar winds, anomalous concentrations of some gases (hydrocarbons and nitriles), and ices in the north polar region during early northern spring. Thus, the interplay of photochemical processes, surface microphysics, and dynamical transport may be as complex as they are on Earth. Titan may also be similar to Earth in having a ``hydrological'' cycle, but involving methane instead of water. Recent ground-based near-infrared observations have indicated activity in the southern summer near Titan's south pole that is suggestive of convective clouds. The observations expected shortly from the battery of instruments on the Cassini orbiter and Huygens probe will be summarized. These will provide the first detailed, global characterization of Titan's dynamic meteorology.

Flasar, F. M.

297

Water Influx at Titan  

NASA Astrophysics Data System (ADS)

Water vapor lines at 227.8 and 254.0 cm(-1) were discovered in Titan's stratosphere from observations taken with the ISO Short Wavelength Spectrometer (SWS) in the grating mode. Line strengths are ~ 8 times the 1sigma statistical noise level, with a resolving power ~ 2000. A recent photochemical model [1] predicts correct H2O/CO2 line strength ratios, provided the actual H2O abundance is 0.4 that of the model. Using this scale factor of 0.4, we infer a water influx of 0.8 - 2.8 x 10(6) mol cm(-2) s(-1) at Titan, referred to an altitude of 700 km. This is comparable to the H2O influx of 0.3 - 5.0 x 10(6) mol cm(-2) s(-1) found at Saturn [2]. We discuss ice dust production and transport mechanisms in the Saturn system that might give rise to such values. References: [1] LARA, L. M., et al. (1996), J. Geophys. Res. - Planets 101, 23261 - 23283. [2] FEUCHTGRUBER, H., et al. (1997), Nature 389, 159 - 162.

Samuelson, R. E.; Bjoraker, G. L.; Coustenis, A.; Lellouch, E.; Salama, A.; Hamilton, D. P.

1998-09-01

298

Titan's Surface By Radarlight  

NASA Astrophysics Data System (ADS)

Titan's surface is characterized at highest resolution by the Cassini Radar operating in synthetic-aperture (SAR) mode, and at larger scales in other radar modes and by other sensors. To date, about 10% of the surface has been imaged by SAR, enabling the classification of surface units based on radar backscatter, shape and texture. Further classification is possible through correlation with infrared data. Of particular note are dark features interpreted as methane or methane/ethane lakes that seem to prefer high latitudes. Other surprisingly earthlike surface units are interpreted as impact craters, longitudinal dunes, cryovolcanics and channels. Other radar data suggest that at global scales, Titan's surface is predominantly a low dielectric material, variably penetrable by radar, with low (100 m to 1 km) relief. Overall, a young surface is revealed, with ample evidence of modification by wind, impact, moving liquid, and (probably) tectonics. In this talk we will review the available data, discuss correlations and differences with data from other sensors, and summarize work to date that relates observed phenomena to understanding the processes at work on the surface of this fascinating moon. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Elachi, Charles; Wall, S.; Lopes, R.; Soderblom, L.; Lunine, J.; Lorenz, R.; Janssen, M.; Kirk, R.; Cassini RADAR Team

2006-09-01

299

Titan Recreation-Intramural Sports Student Engagement Report  

E-print Network

Titan Recreation-Intramural Sports Student Engagement Report FY 2010-2011 Purpose Statement Titan and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive play, team building and interpersonal skills. Leadership and participation opportunities within Titan

de Lijser, Peter

300

Titan Recreation-Open Recreation Student Engagement Report  

E-print Network

Titan Recreation-Open Recreation Student Engagement Report FY 2010-2011 Purpose Statement Titan and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive play, team building and interpersonal skills. Leadership and participation opportunities within Titan

de Lijser, Peter

301

Titan Recreation-Group Fitness Student Engagement Report  

E-print Network

Titan Recreation-Group Fitness Student Engagement Report FY 2012-2013 Purpose Statement Titan fitness and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive within Titan Recreation are designed to enhance social, psychological and physiological development

de Lijser, Peter

302

Titan Recreation-Intramural Sports Student Engagement Report  

E-print Network

Titan Recreation-Intramural Sports Student Engagement Report FY 2011-2012 Purpose Statement Titan fitness and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive within Titan Recreation are designed to enhance social, psychological and physiological development

de Lijser, Peter

303

Titan Recreation-Group Fitness Student Engagement Report  

E-print Network

Titan Recreation-Group Fitness Student Engagement Report FY 2010-2011 Purpose Statement Titan and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive play, team building and interpersonal skills. Leadership and participation opportunities within Titan

de Lijser, Peter

304

Titan Recreation-Intramural Sports Student Engagement Report  

E-print Network

Titan Recreation-Intramural Sports Student Engagement Report FY 2012-2013 Purpose Statement Titan fitness and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive within Titan Recreation are designed to enhance social, psychological and physiological development

de Lijser, Peter

305

Titan Recreation-Open Recreation Student Engagement Report  

E-print Network

Titan Recreation-Open Recreation Student Engagement Report FY 2011-2012 Purpose Statement Titan and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive play, team building and interpersonal skills. Leadership and participation opportunities within Titan

de Lijser, Peter

306

Titan Recreation-Open Recreation Student Engagement Report  

E-print Network

Titan Recreation-Open Recreation Student Engagement Report FY 2012-2013 Purpose Statement Titan and overall wellness. Titan Recreation also provides opportunities for cooperative and competitive play, team building and interpersonal skills. Leadership and participation opportunities within Titan

de Lijser, Peter

307

Characterization of micromachined piezoelectric PZT force sensors for dynamic scanning force microscopy  

NASA Astrophysics Data System (ADS)

The key component for the piezoelectric scanning force microscopy (SFM) is the piezoelectric force-sensing microcantilever. In this article, the resonance frequency and quality factor of Pb(Ti,Zr)O3 (PZT) microcantilevers; effective Young's modulus and piezoelectric Pb(Ti,Zr)O3 property of PZT layer of piezoelectric microcantilevers are discussed. The PZT microcantilevers after poling have quality factors such as 204 to 248 in air, and 608 to 1094 in vacuum. The calculated spring constants are in the range of 1.0-30.0 N/m for cantilevers with 0.64-1.7-?m-thick PZT layer and 125-300 ?m length. The force sensitivity and resolution of the PZT microcantilever are studied when it is oscillated by an external oscillator and applied to the cyclic contact SFM. Then the real transverse piezoelectric coefficient d31 of piezoelectric PZT thin films is derived from the measured sensitivity and effective Young's modulus. The derived effective Young's moduli of PZT layers slightly increases from 53.5 to 58 GPa as the thickness of the PZT layer increases. The d31 is around -35 pC/N which is about 8 times larger than the value of ZnO, and half the value of bulk PZT ceramics. The sensitivity of 0.98 fC/nm can be obtained by PZT force sensors. The longitudinal resolution obtained is 1.5 Å at a bandwidth of 125 Hz. Cantilevers with proper characteristics for different applications can be predicted, designed, and fabricated via the adjustment of the thickness ratio of each layer and the total thickness of the cantilever. Very clear images of an evaporated Au film on a smooth glass plate are obtained by an SFM with a PZT force sensor.

Lee, Chengkuo; Itoh, Toshihiro; Maeda, Ryutaro; Suga, Tadatomo

1997-05-01

308

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

309

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

310

PRESSURE CONTROL CHARACTERISTICS OF ELECTRO-PNEUMATIC REGULATOR WITH TWO MULTILAYERED PZT VALVES  

Microsoft Academic Search

This paper presents pressure control method using the electro-pneumatic regulator with two multilayered PZT valves. An electro-pneumatic regulator is a type of pressure control valve that is a combination of a poppet valve for main pressure control, two multilayered PZT valves for pilot pressure control, a microprocessor with a feedback controller and a pressure sensor. The benefits of bender type

So-Nam Yun; Young-Bog Ham; Jung-Ho Park; Deok-Yong Ham; Il-Young Lee

2008-01-01

311

Flow control valve for pneumatic actuators using particle excitation by PZT vibrator  

Microsoft Academic Search

This paper reports a new flow control valve for pneumatic actuators that has a lightweight and simple structure and uses particle excitation by PZT vibrator. The flow control valve in this report consists of an orifice plate which has plural orifices, PZT vibrator which is adhered on the orifice plate and iron particles. The valve is normally closed, because air

Daisuke Hirooka; Koichi Suzumori; Takefumi Kanda

2009-01-01

312

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.

313

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

314

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

315

Titan's Geology as Viewed by the Cassini Titan Radar Mapper  

NASA Astrophysics Data System (ADS)

Cassini's Titan Radar Mapper has imaged the surface of Titan on 8 flybys to date, collecting Synthetic Aperture Radar (SAR) data at spatial resolution ranging from about 300 m to about 2 km. These radar images reveal that Titan's surface has been modified by both endogenic (volcanism, tectonism) and exogenic (impact cratering, erosion) processes, with no process dominating in an obvious way. Although less than 15 % of the surface of Titan has been imaged to date using SAR, the acquired swaths are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. Cryovolcanic units have been identified in SAR images mostly at mid-latitudes (40-60 N), these include the construct Ganesa Macula, several calderas with associated flows, and large cryovolcanic flows. Flybys over high northern latitudes have shown lacustrine features, the distribution of these features is consistent with colder temperatures and more precipitation at high latitudes. Some of the depressions filled by the lakes may be volcanic calderas, but a thermokarstic origin is also possible (Mitchell et al., Lunar Planet Sci. Conf. XXXVIII, 2007). Ridges and mountains that are interpreted to be of tectonic origin have been seen mostly at low latitudes (Radebaugh et al., Lunar Planet Sci. Conf. XXXVIII, 2007), while drainage channels appear common at all latitudes (Lorenz et al., Plan. Space Sci., submitted). Fields of dunes (Titan's "sand seas") are mostly equatorial, but a few isolated patches of dunes extend as far north as ~60 degrees. The distribution and orientation of dunes is as expected from Titan's winds (Lorenz et al., 2006, Science 312; Radebaugh et al., Icarus, submitted). Erosion by fluvial processes is likely to have occurred on a global scale. The small number of definitive impact craters suggests that these geologic processes are erasing or burying the majority of impacts. Future data will allow us to further constrain the distribution of tectonism and volcanism, providing valuable input for models of Titan's interior.

Lopes, R. M.; Stofan, E. R.; Wood, C.; Robshaw, L.; Mitchell, K. L.; Radebaugh, J.; Lorenz, R.; Lunine, J.; Wall, S. D.; Kirk, R.; Cassini RADAR Team

2007-05-01

316

TITAN Overview 1 TITAN: A NextGeneration Infrastructure for Integrating  

E-print Network

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

California at Berkeley, University of

317

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

E-print Network

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

Gurnett, Donald A.

318

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

319

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

320

Mapping of Titan: Results from the first Titan radar passes  

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

321

Chemical reactions in the Titan’s troposphere during lightning  

NASA Astrophysics Data System (ADS)

In the lower troposphere of the Titan the temperature is about 90 K, therefore the chemical production of compounds in the CH 4/N 2 atmosphere is extremely slow. However, atmospheric electricity could provide conditions at which chemical reactions are fast. This paper is based on the assumption that there are lightning discharges in the Titan's lower atmosphere. The temporal temperature profile of a gas parcel after lightning was calculated at the conditions of 10 km above the Titan's surface. Using this temperature profile, composition of the after-lightning atmosphere was simulated using a detailed chemical kinetic mechanism consisting of 1829 reactions of 185 species. The main reaction paths leading to the products were investigated. The main products of lighting discharges in the Titan's atmosphere are H 2, HCN, C 2N 2, C 2H 2, C 2H 4, C 2H 6, NH 3 and H 2CN. The annual production of these compounds was estimated in the Titan's atmosphere.

Kovács, Tamás; Turányi, Tamás

2010-06-01

322

Low-temperature anisotropic diffusion of helium in zircon: Implications for zircon (U–Th)\\/He thermochronometry  

Microsoft Academic Search

In the last decade the zircon (U–Th)\\/He (ZHe) thermochronometer has been applied to a variety of geologic problems. Although bulk diffusion coefficients for He in zircon are available from laboratory step-heating experiments, little is known about the diffusion mechanism(s) and their dependence on the crystallographic structure of zircon. Here, we investigate the diffusion of He in perfectly crystalline zircon using

Martin Reich; Rodney C. Ewing; Todd A. Ehlers; Udo Becker

2007-01-01

323

Low-temperature anisotropic diffusion of helium in zircon: Implications for zircon (U Th)\\/He thermochronometry  

Microsoft Academic Search

In the last decade the zircon (U Th)\\/He (ZHe) thermochronometer has been applied to a variety of geologic problems. Although bulk diffusion coefficients for He in zircon are available from laboratory step-heating experiments, little is known about the diffusion mechanism(s) and their dependence on the crystallographic structure of zircon. Here, we investigate the diffusion of He in perfectly crystalline zircon

Martin Reich; Rodney C. Ewing; Todd A. Ehlers; Udo Becker

2007-01-01

324

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

325

Titan's Spectacular Volte-Face  

NASA Astrophysics Data System (ADS)

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

Griffith, Caitlin A.

2013-10-01

326

Synthesis and characterization of new cystalline titanates  

E-print Network

Inorganic Compound Intercalated Titanates. . . . . III EXPERIMENTAL METHODS. . . . . 3. 1 Catalyst Preparation . 3. 1. 1 Small Batches. 3. 1. 2 Large Batches. 3. 2 Intercalating the Titanates . . . 3. 2. 1 Swelling the Titanates . 3. 2. 2 Pillaring... the Titanates. 3. 3 Apparatus. 3. 3. 1 Reaction Vessels . . . IV SYNTHESIS CONDITIONS . . 4. 1 Summary of Small Batches Preparation. . 12 . . . 12 . 15 15 15 . 21 . . . 23 . 23 . . . . . 23 25 25 . . . . . 28 28 vu TABLE OF CONTENTS (Continued...

Nge, Renita

2012-06-07

327

Helium-ion implanted waveguides in zircon  

NASA Astrophysics Data System (ADS)

Zircon can be amorphised by ion implantation and the damaged layer is of a lower refractive index than the original crystal. This index change has been used to define optical waveguides. Data are presented on the refractive-index profiles, their dose dependence and the effects of different implant temperatures. Annealing studies reveal an interesting pattern in which below 350°C the index change is reduced, but at higher temperatures it is re-established. The details of the annealing effects are dose dependent. A defect model is discussed. Finally, the possibility of rare-earth doped zircon laser waveguides is mentioned.

Babsail, L.; Hamelin, N.; Townsend, P. D.

1991-07-01

328

Economical Nanoactuator Alternatives to Lead Zirconium Titanate  

NASA Astrophysics Data System (ADS)

This paper describes using inexpensive commercially available ceramic capacitors as a substitute for the lead containing and relatively expensive PZT based nano actuators. A sample PZT actuator is compared with actuators made from both X5R and Y5V type ceramic dielectric capacitors using white light interferometry and a spectrometer. This work is useful in that it can provide nano-motion capability to budget constrained undergraduate and graduate level research laboratories. Additionally, unlike the PZT material the alternative ceramic materials do not contain lead which is needed to create products compliant with the European Rohs (Restriction On Hazardous Substances) initiative.

Wang, Jin; Elghoul, Gabe; Peters, Stephen

2012-06-01

329

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

330

Applicant # Titan Student Centers Governing Board  

E-print Network

Applicant # Titan Student Centers Governing Board 2011-12 Application Packet General Information 1. The Titan Student Centers is a major program operated as part of the Associated Students, CSUF, Incorporated, and an on-campus non-profit organization serving the needs of CSU Fullerton students. The Titan Student

de Lijser, Peter

331

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

E-print Network

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

Yelle, Roger V.

332

Titan's Prolific Propane  

NASA Astrophysics Data System (ADS)

Propane (C3H8) was first detected on Titan by the Voyager 1 IRIS spectrometer in 1980, which identified four stratospheric emission bands (?21 at 748 cm-1, ?16 at 922 cm-1, ?15 at 1054 cm-1 and ?7 at 1158 cm-1). Subsequent analyzes of this dataset have largely focused on the strongest of these bands (?21) to infer the VMR (~ 7×10-7 in the stratosphere and relatively uniform with latitude), although it is significantly disadvantaged by being coincident with a strong R-branch line of acetylene. The Composite Infrared Spectrometer (CIRS) onboard Cassini is now providing the most complete infrared mapping of Titan yet obtained. Prior results have included the retrieval of the vertical and latitudinal profiles of minor gas species, including propane, again exclusively via the ?21 band, the only band for which a linelist is publicly available. We present new modeling of CIRS low-latitude limb spectra acquired from 2004 to 2008. The residuals after modeling all gases except propane clearly show all four bands detected by IRIS, now at much higher signal to noise. In addition, we show that four further bands are clearly evident once the emissions of methane (CH4) and ethane (C2H6) have been modeled and subtracted out: ?8 at 869 cm-1, ?14 at 1338 cm-1, ?13 at 1376 cm-1 and ?19 at 1472 cm-1). Using a new line list for the bands in the range 1300 to 1500 cm-1, we model the ?14, ?13 and ?19 emission bands and compare to abundances retrieved using the ?21 at 748 cm-1. This work has several purposes. Firstly, we demonstrate the urgent need for laboratory spectroscopic measurements of the propane bands at 869, 922, 1054 and 1158 cm-1 leading to line strength listings suitable for spectral calculations. Secondly, we show that the current line list for the 748 cm-1 band does not fit the data accurately, and requires a new spectroscopic study. Finally, we discuss the possibility of new gaseous molecular detections in the regions dominated by these ubiquitous propane bands, once they can be properly modeled.

Nixon, C. A.; Jennings, D. E.; Bezard, B.; Teanby, N. A.; Irwin, P. G.; Hewagama, T.; Flaud, J.; Sharpe, S. W.; Coustenis, A.; Flasar, F. M.

2008-12-01

333

Structure and electrical properties of AlN films prepared on PZT layers with different orientations  

NASA Astrophysics Data System (ADS)

c-Axis oriented AlN films were prepared on (100)-, (110)-, and (111)-oriented PZT layers by DC reactive magnetron sputtering. The evolution of c-axis preferential orientation, surface microstructure and electrical properties of the synthesized films was investigated as a function of PZT orientation. The X-ray diffraction results showed that a nearly stress free AlN film with full width at half maximum value of the rocking curve of 3.7°, can be successfully synthesized at (111)-orientated PZT layers. The change in the morphological properties with PZT orientation was investigated using the scanning electron microscopy and atomic force microscopy techniques. The morphology of the AlN films, grown on (111) PZT films, revealed good interface quality with surface roughness of 5.9 nm compared to other samples. The electrical property of AlN/PZT heterostructures can be effectively improved by introducing the AlN films. Current-voltage curves of the AlN/PZT-(111) films exhibited a lowest leakage current density of approximately 10-10 Acm-2 at-5 V, which showed excellent insulating characteristic. It is expected that this investigation may offer some useful guidelines to the design of MFIS capacitor and other MFIS structure devices.

Meng, Xiangqin; Yang, Chengtao; Yang, Jiancang

2014-01-01

334

Composition of Titan's Surface  

NASA Astrophysics Data System (ADS)

The Huygens Probe returned the first in situ data on Titan's surface composition in January 2005. Although Huygens landed on a dry plain, the Gas Chromatograph Mass Spectrometer (GCMS) showed evidence of methane moisture in the near subsurface suggesting methane precipitation at some time in the past. Heavier organic molecules were not found to be abundant in the atmosphere or at the surface, but the GCMS surface results did show ethane to be present and tentatively identified cyanogen, benzene, and carbon dioxide. During descent, aerosol particles were processed with the Aerosol Collector and Pyroliser; results suggested that the aerosols contain both nitriles and hydrocarbons. The Descent Imager/Spectral Radiometer (DISR also carried by the probe) measured the visible and near-infrared spectral reflectance of the dark plain surface at the landing site. Those data suggest a mixture of water ice, tholin-like materials, and dark neutral material with a blue slope in the near infrared; identification of water ice is suggested but inconclusive. Most remarkably DISR did not detect spectral features, beyond those for methane, for a wide range of spectrally active hydrocarbon and nitrile compounds that had been expected to be present on the surface.

Soderblom, L. A.; Barnes, J. W.; Brown, R. H.; Clark, R. N.; Janssen, M. A.; McCord, T. B.; Niemann, H. B.; Tomasko, M. G.

335

The Titan Haze Simulation experiment on COSmIC: Probing Titan’s atmospheric chemistry at low temperature  

NASA Astrophysics Data System (ADS)

The aim of the Titan Haze Simulation (THS) experiment is to contribute to a better understanding of aerosol formation in Titan’s atmosphere through the study of the chemical formation pathways that link the simpler gas phase molecules resulting from the first steps of the N2-CH4 chemistry, to the more complex gas phase precursors of aerosols; and more specifically, to investigate the role of polycyclic aromatic hydrocarbons (PAHs) and nitrogenated polycyclic aromatic hydrocarbons (PANHs), among other hydrocarbons, in this process. In the THS experiment developed at the NASA Ames Cosmic simulation facility (COSmIC), Titan’s atmospheric chemistry is simulated by a pulsed plasma jet expansion at temperature conditions (?150 K) close to those found in Titan’s atmosphere in regions where aerosols are formed. In addition, because of the very short residence time of the gas in the plasma discharge, only the initial steps of the chemistry occur, making the COSmIC/THS a unique tool to study the first and intermediate (when adding heavier precursors to the initial N2-CH4 mixture) steps of Titan’s atmospheric chemistry at low temperature as shown in the study presented here. We further illustrate the potential of COSmIC/THS for the simulation of Titan’s atmospheric chemistry by presenting very promising results from a preliminary comparison of the laboratory data to data from the Cassini Plasma Spectrometer-Ion Beam Spectrometer (CAPS-IBS) instrument.

Sciamma-O'Brien, Ella; Ricketts, Claire L.; Salama, Farid

2014-11-01

336

Elemental distribution in zircon: Alteration and radiation-damage effects  

NASA Astrophysics Data System (ADS)

Isotopic analyses of U, Pb and REE in 144 zircon grains from the Bidoudouma stream, the Republic of Gabon, were performed to study correlation of elemental distribution with geological alteration effects. The U-Pb isotopic results reveal that the zircons formed around 2.8-2.1 Ga ago and altered around 500 Ma ago by igneous activity in association with dolerite dyke intrusion. The REE abundance patterns of the U-Pb discordant zircons are characterized by high contents of REE (977-98,154 ppm), small LREE-HREE fractionations and distinctly positive Eu anomalies. The discordant zircons also contain significant amounts of non-formula elements such as Ca, Mn, Al and Fe; whereas, their contents of Zr and Si are 1-15% lower than those of concordant zircon. Non-formula elements and REE, especially LREE, were incorporated into metamict zircon in association with Pb-loss, which indicates that the non-formula elements and REE substituted for Zr and Si. Judging from this correlation among the contents of non-formula elements, when zircon was initially altered, Fe substituted for major elements of zircon. After the saturation of Fe, Ca and Mn were incorporated into zircon together with REE and Al followed by Ca. The metamict zircons contain large amount of U (?8215 ppm), which indicates that U had not migrated from zircon grain in association with the Pb-loss.

Horie, Kenji; Hidaka, Hiroshi; Gauthier-Lafaye, François

337

Model-based, closed-loop control of PZT creep for cavity ring-down spectroscopy  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

338

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

339

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

340

Investigating the plasma environment at Titan's orbit  

NASA Astrophysics Data System (ADS)

Prior to Cassini's arrival at Saturn, nitrogen ions were thought to dominate heavy plasma in Saturn's magnetosphere and that Titan's atmosphere was the source of this nitrogen. Therefore, the presence of a Titan nitrogen torus was anticipated. However, it is now known water-group ions dominate Saturn's heavy ion plasma. While nitrogen ions have been detected beyond the orbit of Rhea, they appear to be originating from the Enceladus plumes with little nitrogen plasma detected in the magnetosphere near Titan's orbit. These results appear inconsistent with the expectation that Titan’s dense relatively unprotected atmosphere should provide a significant source of heavy particles to Saturn’s magnetosphere. This inconsistency suggests that the plasma environment at Titan’s orbit is much more complex than originally anticipated. In this talk, we expand on our previous research that categorizes the plasma environments near Titan to include all locations along Titan’s orbit. Using these categories, we develop characteristic plasma spectra of each type of environment and use these results in a 3D Monte Carlo model to examine the extent to which Titan could possibly be generating a neutral particle torus.

Smith, H. T.; Rymer, A. M.; Johnson, R. E.; Mitchell, D. G.; Wellbrock, A.; Coates, A. J.; Young, D. T.

2010-12-01

341

Mass determination of hypervelocity microparticles using a piezoelectric PZT element  

NASA Astrophysics Data System (ADS)

A mass observed with a piezoelectric element is discussed using hypervelocity particles accel-erated by the Van de Graaff accelerator. Since the response of the PZT element is velocity-dependent, the particle mass can be derived using calibration formulas that depend on the velocity. When the velocity during collision exceeds 20 km/s, the piezoelectric element produces a pulsed signal. Then, the rise time and the amplitude of the pulsed signal are well correlated. If the rise time and the amplitude are measured pair off, the response to the collision is classified into three groups [1]. If the calibration formulas can be established in each group, the mass is determined. Let define the deviation by (1) (mm-m0)/m0 (1) where mm is the mass value obtained using the calibration formulas of each group and m0 is that by the time of flight method, respectively. The deviation distributes like a Gaussian form. The mass can be reproduced within 40 When the velocity is less than 10 km/s, the output is of a characteristic form, with which the collision time is exactly determined. The amplitude is subject not only to the particle momentum p but also to the charge q of particle. Then, the PZT element is sensitive to q before the particle arrives at the element during flight time t, if q ? 50 fC. Since the sensitive distance d is calibrated with respect to q, the velocity v and the mass m are obtained; v = d /t, and m = p/v. The deviation defined by (1) distributes like a Gaussian form. The mass can be reproduced described above. Reference [1] T.Miyachi et al., submitted for publication in Adv. Space Res.

Miyachi, Takashi; Takechi, Seiji; Kawachi, Yuya; Shibata, Hiromi; Okudaira, Osamu; Kobayashi, Masanori; Nakamura, Maki; Iwai, Takeo; Gruen, Eberhard; Srama, Ralf

342

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

343

An improved thick-film piezoelectric material by powder blending and enhanced processing parameters  

Microsoft Academic Search

This paper details improvements of the d33 coefficient for thick-film lead zirconate titanate (PZT) layers. In particular, the effect of blending ball and attritor milled powders has been investigated. Mathematical modeling of the film structure has produced initial experimental values for powder combination percentages. A range of paste formulations between 8:1 and 2:1 ball to attritor milled PZT powders by

Russel Torah; Steve P. Beeby; Neil M. White

2005-01-01

344

Enhancement of photocurrent in ferroelectric films via the incorporation of narrow bandgap nanoparticles.  

PubMed

A novel nanostructured ferroelectric photovoltaic material, consisting of the ferroelectric lead zirconate titanate (PZT) film and Ag(2) O semiconductor nanoparticles of comparatively narrow bandgap, has demonstrated a remarkable enhancement in the photovoltaic effects and the highest light-electricity conversion efficiency among those PZT-based photodiodes previously reported. This work sheds light on the design and enhanced performance of new optoelectronic and solar energy devices. PMID:22278739

Yang, Xiaoluan; Su, Xiaodong; Shen, Mingrong; Zheng, Fengang; Xin, Yu; Zhang, Lu; Hua, Muchuan; Chen, Yajie; Harris, V G

2012-03-01

345

Phase correction in piezoelectric photoacoustic Fourier transform infrared spectroscopy of mica  

NASA Astrophysics Data System (ADS)

Piezoelectric photoacoustic IR spectra of mica are obtained using a Fourier transform IR spectrometer and lead zirconate titanate (PZT) as a detector. The spectra exhibit negative intensities and transmission like bands, instead of more conventional absorption bands generally observed with a gas- microphone cell. Correct spectra of mica/PZT are calculated only when the interferogram phase is constrained to the first and fourth quadrants, similar to the case in differential spectroscopy where negative intensities occur.

Zhang, S. L.; Michaelian, Kirk H.; Burt, James A.

1997-02-01

346

Titan's chemical complexity  

NASA Astrophysics Data System (ADS)

We review here our current knowledge of Titan's gas phase chemistry. We base our discussion on photochemical models as well as on laboratory experiments. We identify the lower mass positive [1,2] and negative [3] ions detected in the upper atmosphere and we show that their formation is a direct consequence of the presence of heavy neutrals. We demonstrate that the observed densities of CO, CO2 and H2O can be explained by a combination of exogenous O, and OH/H2O input [4]. We argue that benzene [5] and ammonia [6] are created in the upper atmosphere through complex chemical processes involving both neutral and ion chemistry. These species diffuse downward where they are at the origin of heavier aromatics and amines, respectively. Finally, we discuss the impact on hydrocarbon densities of recent theoretical calculations of the rate constants of association reactions [7]. [1] V. Vuitton, R. V. Yelle and V. G. Anicich, Astrophys. J., 647, L175 (2006). [2] V. Vuitton, R. V. Yelle and M. J. McEwan, Icarus, 191, 722 (2007). [3] V. Vuitton, P. Lavvas, R. V. Yelle, M. Galand, A. Wellbrock, G. R. Lewis, A. J. Coates and J.-E. Wahlund, Planet. Space Sci., 57, 1558 (2009). [4] S. M. Hörst, V. Vuitton, and R. V. Yelle, J. Geophys. Res., 113, E10006 (2008). [5] V. Vuitton, R. V. Yelle and J. Cui, J. Geophys. Res., 113, E05007 (2008). [6] R. V. Yelle, V. Vuitton, P. Lavvas, S. J. Klippenstein, M. A. Smith, S. M. Hörst and J. Cui, Faraday Discuss., 147, 31 (2010). [7] V. Vuitton, R. V. Yelle, S. J. Klippenstein and P. Lavvas, Astrophys. J., in press.

Vuitton, Veronique

2012-04-01

347

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

348

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

349

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

SciTech Connect

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

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

2010-01-01

350

Effect of Si3N4 nanoparticulates on the mechanical and electrical properties of PZT ceramics  

NASA Astrophysics Data System (ADS)

PZT/xSi3N4 ceramics (when x=0, 0.1, 0.5 and 1 wt.%) were prepared by a solid-state mixed-oxide method and sintered at 1125 °C for 2 h. X-ray diffraction results suggested that the addition of Si3N4 nanoparticulates did not significantly affect the unit cell and tetragonality of PZT. The addition of 0.1 wt.% Si3N4 effectively increased the density and reduced the grain size of PZT ceramics. These changes played an important role in hardness and fracture toughness improvement. The maximum room temperature dielectric constant was achieved in a PZT/0.1 wt.% Si3N4 sample. Within the Si3N4-containing samples, the high-temperature dielectric values and ferroelectric properties seemed to increase with increasing concentrations of Si3N4.

Namsar, Orapim; Watcharapasorn, Anucha; Jiansirisomboon, Sukanda

2010-05-01

351

A study of powder size combinations for improving piezoelectric properties of PZT thick-film devices  

Microsoft Academic Search

Summary: This paper details investigations into the effects of different powder size ratios on the d33 coefficient of thick-film PZT layers. The two powders used were 5H type PZT supplied by Morgan Electro Ceramics Ltd. These were prepared using ball milling for the large particles, ~2um, and attritor milling for the small particles, ~1um. These powders were mixed with 10%

R. N. Torah; S. P. Beeby; N. M. White

352

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

353

Effects of Ti\\/Ir top electrodes of PZT capacitors on the hydrogen related degradation  

Microsoft Academic Search

Hydrogen annealing damages on properties of PZT capacitors and a role of Ti\\/Ir hybrid structure top electrodes on capacitors are investigated in this study. It is demonstrated that the capacitors with Ti\\/Ir structure top electrodes improve a resistance against hydrogen related degradation. As the thickness ratio of Ti\\/Ir increases, the capacitors show enhanced endurance against hydrogen damages. Especially, PZT (350nm)

Jiyoung Kim; June-Mo Koo; Tae Ho Kim; Ilhwan Bang

2000-01-01

354

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

E-print Network

. The onset of measurable nonlinearity is observed to be accompanied by the appearance of hysteresis loops to make transducers, resonators;"ac- tuators, motors, sonars, etc. .One of the limitations for practical

Cao, Wenwu

355

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

356

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

357

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

E-print Network

gauges, pressure transducers, and accelerometers. Bulk ferroelectric ceramic sensors have certain substrates by a sol-gel method and crystallized with preferred 111 or 100 orientation. Both the piezoelectric Ferroelectric ceramics have been employed extensively in a variety of sensors and actuators including strain

Sottos, Nancy R.

358

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

359

Titan. [overview of current knowledge  

NASA Technical Reports Server (NTRS)

The paper reviews current knowledge about Titan's atmosphere, surface, interior, and nearby environment. An attempt is made to place the satellite's history within the context of the formation of the Saturn system and to describe possible evolutionary paths for its atmosphere and interior.

Pollack, J. B.

1981-01-01

360

Campus Contacts Titan Bookstore Cafe  

E-print Network

Sale - Titan Bookstore March 11th - 15th Shea Homes Scholarship Deadline March 14th Research Week March, a special cohort program for Child and Adolescent Studies, and the introduction of a Nursing Simulation Lab to coincide with increased classes in Nursing. What we will soon be able to develop are program plans

de Lijser, Peter

361

Photochemical Modeling of Titan's Atmosphere  

Microsoft Academic Search

We have developed a new photochemical model of Titan's atmosphere which includes all the important compounds and reactions in spherical geometry from the surface to 1240 km. Compared to the previous model of Yung et al. (1984, Astrophys. J. Suppl. 55, 465-506), the most significant recent change in the reactions used is the updated methane photodissociation scheme (Mordaunt et al.

D. Toublanc; J. P. Parisot; J. Brillet; D. Gautier; F. Raulin; C. P. McKay

1995-01-01

362

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

363

Titan's gas and plasma torus  

NASA Technical Reports Server (NTRS)

The implications of the Voyager observations for a steady state model of a torus of hydrogen and nitrogen neutral gas and plasma are assessed. Constraints are placed on the nitrogen neutral density, the neutral hydrogen and nitrogen escape fluxes (from Titan), and the diffusion rate in terms of observed or inferred quantities. The results obtained are consistent with the Voyager observations.

Eviatar, A.; Podolak, M.

1983-01-01

364

The dynamics of Titan's troposphere.  

PubMed

While the Voyager mission could essentially not reveal the dynamics of Titan's troposphere, useful information was obtained by the Cassini spacecraft and, particularly, by the Huygens probe that landed on Titan's surface; this information can be interpreted by means of numerical models of atmospheric circulation. The meridional circulation is likely to consist of a large Hadley circulation asymmetric about the equator, but is susceptible to disruption by turbulence in clouds. The zonal wind in the troposphere is comparable to or even weaker than that in the terrestrial troposphere and contains zones of easterlies, much in contrast to the super-rotating stratosphere. Unique to Titan is the transition from a geostrophic to cyclostrophic wind balance in the upper troposphere. While Earth-like storm systems associated with baroclinic instability are absent, Saturn's gravitational tide introduces a planetary wave of wavenumber 2 and a periodical variation in the wind direction in the troposphere. Unlike on Earth, the wind over the equatorial surface is westerly. The seasonal reversal in the Hadley circulation sense and zonal wind direction is predicted to have a substantial influence on the formation of dunes as well as variation of Titan's rotation rate and length of day. PMID:19019782

Tokano, Tetsuya

2009-02-28

365

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

366

An Endogenic Origin of Titan,s Methane  

NASA Astrophysics Data System (ADS)

Methane is abundant in the atmosphere and at the surface of Titan. Rapid photochemical dissociation of methane in the atmosphere implies its supply from the interior of the satellite, an implication that is confirmed by the difference in the fractionation of carbon and nitrogen isotopes [1]. Recent models for giant planet formation do not support the concept of high-pressure sub-nebulae [2] in which methane forms through grain-catalyzed reactions [3]. Therefore, we start from the assumption that most of the carbon in the Saturnian system was accreted from the surrounding solar nebula in the form of macromolecular organic carbon particles, SiC, graphite, nano-diamonds and amorphous carbon grains, as it is found in the unequilibrated chondrites and in the interstellar medium. We further assume that the relatively low abundances of noble gases in Titan,s present atmosphere indicate that the planetesimals that formed the satellite came from a warm (T > 75K) environment where methane, even if present, was not trapped directly [1,4]. Following these assumptions, we develop the idea that Titan,s methane could be endogenic [4]. Here we examine the possible chemical pathways for producing methane in Titan,s interior. The icy planetesimals that formed Titan ensured the incorporation of water ice in the growing satellite, together with reduced rocky components represented by solar nebula condensates, which included Fe-rich metal, presolar grains and the carbon species mentioned above. Decay of radionuclides and heat released during accretion supplied energy to melt ice. Interaction of water with rocks caused mineral oxidation and formation of ferrous silicates, magnetite, phosphates and other salts. Hydrogen was produced in all oxidation reactions and the water-iron reaction provided a major source of H2. Deep below the surface, hydrothermal reactions caused disproportionation of organic compounds through the overall pathway: organic matter + H2O > CO2 + CH4 [c.f., 5]. Although both O-bearing carbon species (e.g., carboxylic acids, carbonates) and H-rich compounds (aliphatic hydrocarbons) form through C disproportionation, the H2-rich environment favored generation of H-rich organic compounds and methane. In addition, high-temperature hydrogenation of inorganic carbon also led to formation of methane. The resulting gas could be stored as clathrates in Titan's watery mantle for subsequent release to the atmosphere. We cannot exclude the possibility that methane generation continues to the present time. References: [1] Niemann H.B. et al. (2005) Nature, in press. [2] Canup R. and Ward W.R. (2002) Astron. J. 124, 3404-3423. [3] Prinn R.G. and Fegley B. (1981) Ap. J. 249, 308-317. [4] Owen T., Atreya S. and Niemann H.B. (2005) Uspekhi Physicheskikh Nauk 175, 664-668. [5] Price L.C. and DeWitt E. (2001) GCA 65, 3791-3826.

Zolotov, M. Y.; Owen, T.; Atreya, S.; Niemann, H. B.; Shock, E. L.

2005-12-01

367

Titan's Chemical Complexity and Dust  

NASA Astrophysics Data System (ADS)

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

Vuitton, Véronique

368

Modeling of Carbochlorination of Zircon in Fluidized Bed Reactor  

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

369

Rare-earth diffusion in zircon  

Microsoft Academic Search

Diffusion rates for three rare-earth elements (REEs: Sm, Dy, Yb) have been measured in synthetic and natural zircon. REE-phosphate powders were used as the source of diffusant, with Rutherford backscattering spectrometry (RBS) used to measure REE depth profiles.Over the temperature range 1150–1400°C, the following Arrhenius relations were obtained (diffusion coefficients in m2 s?1 ): log DYb = (7.40±1.15)+(?769±34 kJ mol?12.303

D. J. Cherniak; J. M. Hanchar; E. B. Watson

1997-01-01

370

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

371

Femtosecond laser optimization of piezoceramic cutting  

E-print Network

-Etienne, France. P. CAZOTTES Groupe SAFRAN 75724 Paris, FRANCE Abstract--Ablation characteristics of piezoceramics such as Lead Zirconate Titanate (PZT) are widely used for their mechanical properties in highly integrated. Here femtosecond lasers are used to develop a fast and reproducible cutting process and find the limits

Paris-Sud XI, Université de

372

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-stressed piezoelectric devices are of interest in a variety of aerospace applications. Their performance as a function

373

Materials Letters 17 (1993) 13-20 Nosh-Holland  

E-print Network

Materials Letters 17 (1993) 13-20 Nosh-Holland Microwave calcination lead zirconate titanate Kinetics inc., Bellefonte, PA 16823, USA Received 10April 1993 Microwave calcining of conventionally. Conventionally prepared PZT was calcined with microwave power at 720�C for 45 min, whereas conventional

Ounaies, Zoubeida

374

Copyright (2000) University of Maryland, College Park. All rights reserved. Permission to redistribute the contents without alteration is granted to educational institutions for non-profit or educational purposes if proper  

E-print Network

as the source. Domain Nucleation And Relaxation Kinetics In Ferroelectric Thin Films C. S. Ganpulea) , V piezoresponse microscopy. The 90° domain walls preferentially nucleate the 180° reverse domains during of the remanant polarization in epitaxial lead zirconate titanate (PbZr0.2Ti0.8O3, PZT) ferroelectric thin films

Williams, Ellen D.

375

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

NASA Technical Reports Server (NTRS)

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

Janas, V. F.; Safari, A.

1996-01-01

376

Simultaneous observation of nano-sized ferroelectric domains and surface morphology using scanning nonlinear dielectric microscopy  

Microsoft Academic Search

A new type of scanning nonlinear dielectric microscope (SNDM), with an additional function of simultaneous observation of surface morphology, has been developed. This was achieved by using an electrically conducting atomic force microscopy cantilever as a probe needle. Using this new SNDM, simultaneous measurements of several ferroelectric materials, such as LiNbO3 single crystal and lead zirconate titanate (PZT) thin films

H. Odagawa; Y. Cho

2000-01-01

377

Development of new capacitive strain sensors based on thick film polymer and cermet technologies  

Microsoft Academic Search

In this work, the strain sensing characteristics of new thick film capacitive sensors are presented. New cermet and polymer dielectric pastes based on lead–zirconate–titanate (PZT) and polyvinylidene fluoride (PVDF) have been developed. The screen printing technique has been used to fabricate the sensors on 96% alumina substrates. Various strain gauge characteristics have been studied, including the electrical properties of both

K. I. Arshak; D. McDonagh; M. A. Durcan

2000-01-01

378

Utilisation of smart polymers and ceramic based piezoelectric materials for scavenging wasted energy  

Microsoft Academic Search

Piezoelectric smart polymer and ceramic materials can be deployed as a mechanism to transform mechanical energy into electrical energy that can be stored and used to power portable devices. This paper focuses on the development and comparison of a micropower based harvesting generator using piezoelectric PZT (lead zirconate titanate) ceramic, PVDF (polyvinylidene fluoride) membrane and PP (polypropylene) foam polymer with

I. Patel; E. Siores; T. Shah

2010-01-01

379

Photochemically driven collapse of Titan's atmosphere.  

PubMed

Saturn's giant moon Titan has a thick (1.5 bar) nitrogen atmosphere, which has a temperature structure that is controlled by the absorption of solar and thermal radiation by methane, hydrogen, and organic aerosols into which methane is irreversibly converted by photolysis. Previous studies of Titan's climate evolution have been done with the assumption that the methane abundance was maintained against photolytic depletion throughout Titan's history, either by continuous supply from the interior or by buffering by a surface or near surface reservoir. Radiative-convective and radiative-saturated equilibrium models of Titan's atmosphere show that methane depletion may have allowed Titan's atmosphere to cool so that nitrogen, its main constituent, condenses onto the surface, collapsing Titan into a Triton-like frozen state with a thin atmosphere. PMID:9005844

Lorenz, R D; McKay, C P; Lunine, J I

1997-01-31

380

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

381

Using Zircon to Reconstruct the Magmatic History of Icelandic Rhyolite  

NASA Astrophysics Data System (ADS)

We are investigating zircon in Icelandic rhyolite from major historical eruptions: Askja (1875 AD), Torfajokull (1477 AD), Hekla (1104 AD), and Oraefajokull (1362 AD). This focused study of Icelandic zircon (the first to combine trace element analysis and U-Th dating) adds critical compositional, geochronological and thermal insight into the history of silicic magmatism in Iceland. Icelandic zircons share a number of characteristics that distinguish them from continental arc and interior zircon. CL imaging reveals that they lack complex zoning (evidence for fluctuating conditions) which is common in continental settings. Zoning is weakly displayed except for dark (CL) cores in Oraefajokull and Torfajokull zircons. Elemental analyses reveal low U (<200 ppm except for dark cores), U/Th (<1) and Hf (<10,000 ppm) and high Ti (>10 ppm). Ti-in-zircon thermometry indicates that these zircons grew at temperatures of 800-900C (assuming a(TiO2) ~0.5-0.8). Precision of U-Th disequilibria ages is limited by generally low U and U/Th, but the data demonstrate that (1) the age-range is far less than is common in continental magmatic settings (typically hundreds of thousands to millions of years), but (2) most ages ages are demonstrably older than eruption. Torfajokull, Oraefajokull and Hekla zircon populations all span a range of ages from near-zero to approximately 40ky, with a majority of ages between 10 and 40 ky (extremely low-U Askja zircons yield no useful age information). These findings are corroborated by zircons from prehistoric eruptions of Torfajokull which record a similar history, with the majority of zircon ages predating eruptions by 10-40 ky. Though zircons from all of these volcanoes share many general characteristics, each zircon population is compositionally distinct. Notably, Ti concentrations (thus calculated temperatures) correlate with tectonic setting. Zircons from Askja, an on-rift volcano, grew at the highest estimated temperatures (average ~870C), followed by Torfajokull (propagating rift tip; ~840C), Hekla (just beyond the current rift; ~820C) and Oraefajokull (off-axis, ~800 C). Furthermore, plots of Hf vs. Ti (representative of fractionation and temperature, respectively) reveal that Askja, Torfajokull, and Hekla all have parallel negative slopes, with Askja at the highest Ti and Hf and Hekla at the lowest. Oraefajokull, the sole off-rift example, scatters at generally lower Ti and Hf. Plots of Hf vs. U/Yb show that the Askja zircon population straddle the boundary between MORB and continental fields while zircon from the other volcanic centers cluster in the continental field near the MORB boundary (Grimes et al. 2007).

Carley, T. L.; Miller, C. F.; Wooden, J. L.; Barth, A. P.

2009-12-01

382

A Refined Model of Zircon Saturation in Crustal Magmas  

NASA Astrophysics Data System (ADS)

Improvements in experimental, analytical and computation methodologies together with published studies yielding seemingly contradictory results prompted us to return to the determination of zircon stability in the range of felsic to intermediate melts expected in continental environments. We re-analyzed both the run products from the zircon crystallization study of [1] and a new style of zircon dissolution experiments (up to 25 kbars) using a large radius ion microprobe to constrain a refined zircon solubility model. The new data yield broadly similar patterns as before when arrayed for temperature and confirm that the parameter M [=(K+Na+2Ca)/(Si Al) as molar abundances] is an appropriate compositional proxy for the mechanism by which zircon is dissolved. We used a Bayesian approach to optimize calculation of the coefficients in the zircon solution model, which is given by: ln DZr = (10108±32)/T(K) - (1.16±0.15) * (M-1) - (1.48±0.09), where DZr is the distribution coefficient of Zr between zircon and melt and the errors are at one sigma. Sensitivity tests indicate that temperature and composition are the two dominant controls on zircon solubility in crustal melts with, surprisingly, no observable pressure effect. Our new data together with literature results suggest a weaker dependence of zircon solubility on water content than previously thought. Comparison of the down-temperature extrapolation with natural examples confirms the validity of the model at ca. 700C. [1] Watson and Harrison, 1983. Earth Planet. Sci. Lett 64, 295-304.

Boehnke, P.; Watson, E. B.; Trail, D.; Harrison, T. M.; Schmitt, A. K.

2012-12-01

383

Oxygen isotopic composition and U-Pb discordance in zircon  

USGS Publications Warehouse

We have investigated U-Pb discordance and oxygen isotopic composition of zircon using high-spatial resolution ??18O measurement by ion microprobe. ??18O in both concordant and discordant zircon grains provides an indication of the relationship between fluid interaction and discordance. Our results suggest that three characteristics of zircon are interrelated: (1) U-Pb systematics and concomitant age discordance, (2) ??18O and the water-rock interactions implied therein, and (3) zircon texture, as revealed by cathodoluminescence and BSE imaging. A key observation is that U-Pb-disturbed zircons are often also variably depleted in 18O, but the relationship between discordance and ??18O is not systematic. ??18O values of discordant zircons are generally lighter but irregular in their distribution. Textural differences between zircon grains can be correlated with both U-Pb discordance and ??18O. Discordant grains exhibit either a recrystallized, fractured, or strongly zoned CL texture, and are characteristic of 18O depletion. We interpret this to be a result of metamictization, leading to destruction of the zircon lattice and an increased susceptibility to lead loss. Conversely, grains that are concordant have less-expressed zoning and a smoother CL texture and are enriched in 18O. From this it is apparent that various stages of water-rock interaction, as evidenced by systematic variations in ??18O, leave their imprint on both the texture and U-Pb systematics of zircon. Copyright ?? 2005 Elsevier Ltd.

Booth, A.L.; Kolodny, Y.; Chamberlain, C.P.; McWilliams, M.; Schmitt, A.K.; Wooden, J.

2005-01-01

384

Influence of processing conditions on the structure, composition and ferroelectric properties of sputtered PZT thin films on Ti-substrates  

NASA Astrophysics Data System (ADS)

PZT thin (˜500 nm) films are synthesized on titanium (Ti) substrates by r.f. magnetron sputtering under various processing conditions. Present work aims to investigate the influence of working pressure and post-annealing temperature on the quality of the films. Phase evolution, surface morphology with local chemical composition and dielectric/ferroelectric properties of PZT films have been studied as the functions of working pressure and post-annealing temperature. A working pressure of ˜0.7 Pa and a post-crystallization temperature of ˜650 °C are found to be the optimum processing conditions for growing perovskite PZT films on Ti-substrates. Irrespective of processing conditions, however, all PZT films on Ti-substrates show poor electrical response. Depth dependent change in the chemical states of Pb, Zr, Ti and oxygen within the PZT films and across the PZT/Ti interfaces has also been scrutinized by XPS depth profiling. It is observed that within PZT films, Pb exists both in Pb2+ and Pb0 (metallic-Pb) states. Surfaces of the PZT films are found to be enriched with a thin (˜60 nm) Pb-deficient and Zr-rich pyrochlore/fluorite (Py/Fl) phase. Existence of a thin titanium oxide layer in the form of a TiO2/TiO stack has also been confirmed at the PZT/Ti interface. Processing conditions dependant structural modifications have been correlated with the dielectric and ferroelectric properties of the films.

Bose, Ankita; Sreemany, Monjoy

2014-01-01

385

Titan Oceanography from the Cassini  

NASA Astrophysics Data System (ADS)

While the Cassini-Huygens mission was formulated against the speculative backdrop of a hydrocarbon ocean on Titan, the reality exposed by its measurements a quarter century later has proven more interesting. Instead of a global ocean, Titan has three modest seas, with dozens of small lakes, clustered around its north pole. The south is almost entirely bereft of surface liquids, the probable result of astronomically-forced climate cycles on Titan which are pumping ethane and methane vapor northwards across the equatorial deserts to accumulate in the long rainy season each boreal summer in the present epoch. Cassini’s RADAR instrument mapped the second-largest (~350km) sea, Ligiea Mare, while it was still in winter darkness, and has now covered the sprawling (~1000km) Kraken Mare, revealing shorelines indicating rising sea levels. The mapping allows the construction of numerical models of ocean circulation driven by winds and tides. Radar observations have placed tight limits (mm) on wave heights so far: near-infrared sunglint observations provide separate constraints on surface roughness. We will review latest observations and future plans: it is expected that winds will freshen as we move towards the culmination of the Cassini Solstice Mission in northern midsummer. The Ku-band (2.2cm) radar signals from Cassini penetrate a few meters into the possibly muddy dregs of Ontario Lacus in the south, yet remarkably allowed detection of a bottom echo at Ligeia Mare in a nadir-pointed altimetry observation in summer 2013. This not only allowed a depth estimation of ~170m, but also points to a very ‘clean’ composition, quite possibly rich in methane. This contrasts with near-infrared measurements at Ontario Lacus in the south, which show ethane and possibly an optically-muddy appearance. The stage is now set for detailed modeling of wind-driven and tidal circulations, mixing, stratification, sedimentation and shoreline processes on Titan. Beyond their insights into this environment, Cassini’s observations set the stage for future missions, which might include vehicles that float on, fly over, or even swim in, Titan’s exotic seas.

Lorenz, Ralph

386

Evidence of Titan’s climate history from evaporite distribution  

NASA Astrophysics Data System (ADS)

Water-ice-poor, 5-?m-bright material on Saturn’s moon Titan has previously been geomorphologically identified as evaporitic. Here we present a global distribution of the occurrences of the 5-?m-bright spectral unit, identified with Cassini’s Visual Infrared Mapping Spectrometer (VIMS) and examined with RADAR when possible. We explore the possibility that each of these occurrences are evaporite deposits. The 5-?m-bright material covers 1% of Titan’s surface and is not limited to the poles (the only regions with extensive, long-lived surface liquid). We find the greatest areal concentration to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations, based on the correlation between 5-?m-bright material and lakebeds, imply that there was enough liquid present at some time to create the observed 5-?m-bright material. We address the climate implications surrounding a lack of evaporitic material at the south polar basins: if the south pole basins were filled at some point in the past, then where is the evaporite?

MacKenzie, Shannon M.; Barnes, Jason W.; Sotin, Christophe; Soderblom, Jason M.; Le Mouélic, Stéphane; Rodriguez, Sebastien; Baines, Kevin H.; Buratti, Bonnie J.; Clark, Roger N.; Nicholson, Phillip D.; McCord, Thomas B.

2014-11-01

387

Can Titan generate tori in Saturn's magnetosphere?  

NASA Astrophysics Data System (ADS)

Prior to Cassini's arrival at Saturn, nitrogen ions were thought to dominate heavy plasma in Saturn's magnetosphere and that Titan's atmosphere was the source of this nitrogen. Therefore, the presence of a Titan nitrogen torus was anticipated. However, it is now known water-group ions dominate Saturn's heavy ion plasma. While nitrogen ions have been detected beyond the orbit of Rhea, they appear to be originating from the Enceladus plumes with little nitrogen plasma detected in the magnetosphere near Titan's orbit. These results appear inconsistent with the expectation that Titan's dense relatively unprotected atmosphere should provide a significant source of heavy particles to Saturn's magnetosphere. This inconsistency suggests that the plasma environment at Titan's orbit is much more complex than originally anticipated. In this talk, we expand on our previous research that categorizes the plasma environments near Titan to include all locations along Titan's orbit. Using these categories, we develop characteristic plasma spectra of each type of environment and use these results in a 3D Monte Carlo model to more accurately examine fate of nitrogen and methane escaping Titan's atmosphere. These results are compared to Cassini observations to determine if Titan is capable of generating tori.

Smith, H. T.; Johnson, R. E.; Rymer, A. M.; Mitchell, D. G.

2011-12-01

388

Plausible Organic Synthesis on Titan's Surface  

NASA Astrophysics Data System (ADS)

Titan’s nitrogen and hydrocarbon dominated atmosphere is the site of very complex organic chemistry leading to the production of numerous species including larger molecules from smaller molecular, ionic and radical precursors. Photochemical conversion of methane and other precursors produces smog in the middle to upper layers of the atmosphere, and an organic rain of methane, higher hydrocarbons, and nitrogen-containing aerosols falls onto Titan’s surface, producing an Earth-like terrain of extended river channels that contain a “soup” of several important organic precursors. Here we describe plausible organic chemistry under Titan’s surface and near surface conditions and present synthetic schemes based on acetylene, hydrocyanic acid, and other small organic precursors resulting in the production of larger molecules. Among the products of these reactions are important biological precursors such as nitrogenous bases and amino acids. We present details of several plausible prebiotic organic synthetic routes in Titan’s surface environment and the implications of such chemistries to the overall process of prebiotic evolution on Titan.

Abbas, S. H.; Schulze-Makuch, D.

2009-12-01

389

The magnetic memory of Titan's ionized atmosphere.  

PubMed

After 3 years and 31 close flybys of Titan by the Cassini Orbiter, Titan was finally observed in the shocked solar wind, outside of Saturn's magnetosphere. These observations revealed that Titan's flow-induced magnetosphere was populated by "fossil" fields originating from Saturn, to which the satellite was exposed before its excursion through the magnetopause. In addition, strong magnetic shear observed at the edge of Titan's induced magnetosphere suggests that reconnection may have been involved in the replacement of the fossil fields by the interplanetary magnetic field. PMID:18787164

Bertucci, C; Achilleos, N; Dougherty, M K; Modolo, R; Coates, A J; Szego, K; Masters, A; Ma, Y; Neubauer, F M; Garnier, P; Wahlund, J-E; Young, D T

2008-09-12

390

Modeling and testing of PZT and PVDF piezoelectric wafer active sensors  

NASA Astrophysics Data System (ADS)

Piezoelectric wafer active sensors (PWAS) used in structural health monitoring (SHM) applications are able to detect structural damage using Lamb waves. PWAS are small, lightweight, unobtrusive and inexpensive. They achieve direct transduction between electric and elastic wave energies. PWAS are charge mode sensors and can be used as both transmitters and receivers. The focus of this paper is to find a suitable in situ piezoelectric active sensor for sending and receiving Lamb waves to be used in the SHM of structures with a curved surface. Current SHM technology uses brittle piezoceramic (PZT) wafer active sensors. Since piezoceramics are brittle, this approach could only be used on flat surfaces. The motivation of our research was to explore the use of flexible piezoelectric materials, e.g. piezoelastic polymers such as PVDF. However, PVDF stiffness is orders of magnitude lower than the PZT stiffness, and hence PVDF Lamb wave transmitters are much weaker than PZT transmitters. Thus, our research proceeded in two main directions: (a) to model and understand how piezoelectric material properties affect the behaviour of piezoelectric wafer active sensors; and (b) to perform experiments to test the capabilities of the flexible PVDF PWAS in comparison with those of stiffer but brittle PZT PWAS. We have shown that, with appropriate signal amplification, PVDF PWAS can perform the same Lamb wave transmission and reception functions currently performed by PZT PWAS. The experimental results of PZT-PWAS and PVDF-PWAS have been compared with a conventional strain gauge. The theoretical and experimental results in this study gave a basic demonstration of the piezoelectricity of PZT-PWAS and PVDF-PWAS.

Lin, B.; Giurgiutiu, V.

2006-08-01

391

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

392

Investigation on nanocomposites for pyroelectric infrared sensors  

NASA Astrophysics Data System (ADS)

In order to fabricate a homogeneous pyroelectric thin film of polymer-ceramic composite for un-cooled infrared sensors, ceramic particle size should be as small as possible. Nanoparticles of Lead zirconate titanate and lead zirconate type ceramic were obtained. In this presentation, electrical and pyroelectric properties of PVDF:PZT composite films prepared by Spin-Coat technique are presented, and results are compared with other triglycine sulfate based composites.

Guggilla, Padmaja; Batra, Ashok K.; Aggarwal, Mohan D.; Lal, Ravindra B.

2005-04-01

393

Fire & Ice: Hindenburg and Titanic  

NSDL National Science Digital Library

The National Postal Museum recently created a rather nice in situ exhibit with this great online component to bring together materials on two marvels (and disasters) of modern transportation: the Titanic and the Hindenburg. The exhibit brought together unique items such as postcards and programs in one place so that visitors could learn about these rather fantastic forms of conveyance. The exhibit takes its name from the poem "Fire and Ice" by Robert Frost in which he mused "Some say the world will end in fire, some say in ice." The sections of the exhibit include Life Onboard, Mail Ships, and Technologically Advanced. Visitors can scan through each section to view a number of items, such as a fabric purse from the Hindenburg and a photo of the elaborate squash court on the Titanic. Not surprisingly, the Rarities area contains some postal history treasures, including an envelope sent from the Hindenburg which was discovered in the wreckage.

2012-03-22

394

Aeronomy of Saturn and Titan  

Microsoft Academic Search

The Saturn system presents exciting and unique objects for planetary aeronomy. The photochemistry of H2 and He leads to the formation of an ionosphere. Methane photolysis results in the formation of spectroscopically detectable amounts of C2H6 and C2H2 and in the case of Titan, C2H4. Density profiles of C2H6, C2H2, and PH3 should be indicative of the strength of atmospheric

D. F. Strobel

1978-01-01

395

Hydrodynamic fractionation of zircon age populations in fluvial transport  

NASA Astrophysics Data System (ADS)

Because it is generally assumed that zircon age populations are not significantly fractionated during transport, detrital zircon provenance studies usually characterize locations or units with a single sample. But zircons vary in size by an order of magnitude, ranging from 10s of ?m to a few hundred ?m in length (i.e. coarse silt to medium sand). Hydrodynamic fractionation of grain sizes is therefore likely; and if different age populations have different characteristic sizes, then the population proportions in a given sample are likely to be influenced by local depositional mechanics. Thus, a single sample may not fully characterize zircon populations for a given location or stratigraphic interval. We examined size and age of zircons from twelve locations along the Amazon River, and compared the data with grain size distributions of the host sands. We found that old zircons in the Amazon tend to be smaller (significant at > 2? level), and that there is a significant relationship between median grain size of concordant zircons in a sample and median age of the sample. Furthermore, sands with a larger coarse fraction tend to have larger zircons. The inference is that zircons are fractionated by size; and if size and age are related (as in this example), age populations are likely to be affected. To test whether zircon age populations are affected by local hydrodynamics, we analyzed five sand samples from different sub-environments of a single Amazon River dune (28 m x 1 m). We sampled the upstream and downstream troughs, the stoss, and the upper and lower lee slope. From each sample we obtained 51-71 concordant (100 ±10%) zircon ages (using LA-ICPMS). Using probability density diagrams and mixture modeling to define ages and proportions of population components, we found significant differences (2? level) between samples. In the most extreme case, one sample had an age population not seen in any other, and lacked a population that was present in all other samples. As all samples came from the same site, with hydrodynamic microenvironment the only variable, our results suggest that there may be significant sedimentological effects on zircon age populations. Zircon age populations are not independent of grain size, and hydrodynamic fractionation can affect the number and relative proportions of age populations in a given sample. Although further analyses are necessary to confirm our interpretations, these initial results suggest that single samples may not reliably characterise zircon populations. Comparative provenance analysis may require samples from multiple micro- environments to produce a representative picture of zircon age distributions.

Lawrence, R. L.; Cox, R.; Mapes, R. W.; Coleman, D. S.

2008-12-01

396

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

397

Safe prescribing: a titanic challenge.  

PubMed

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

2012-10-01

398

Synthesis and properties of barium titanate solid solution thin films deposited on copper substrates  

NASA Astrophysics Data System (ADS)

Barium titanate thin films were deposited via chemical solution deposition using a hybrid-chelate chemistry directly on copper foil substrates. A process was developed to crystallize and densify the ferroelectric films at 900°C by using a reductive atmosphere containing nitrogen, hydrogen, water vapor, and oxygen impurities such that film constituents were oxidized to form barium titanate and the foil substrate remained metallic. The crystallized films are polycrystalline with equiaxed morphology and average grain diameters in excess of 100 mn. The dielectric properties exhibit permittivities in excess of 1800 at room temperature and zero bias with tunabilites of greater than 90% and high field loss tangents of less than 1%. The phase transition temperature and temperature coefficient of capacitance modified by partially substituting zirconium, hafnium, and tin for titanium. The resulting films were single phase and the phase transition shifts were consistent with bulk materials. A reduction in permittivity was observed for increasing substituent level and was attributed to a reduction in grain size for both barium titanate zirconate and barium titanate hafnate. Processing conditions were chosen to stabilize Sn2+ during the firing process in an attempt to flux the system and increase grain size. The barium titanate stannate films had less reduction in grain size per substituent level than either zirconium or hafnium, however a similar reduction in permittivity was observed. The diminished dielectric response was explained by a defect reaction involving divalent tin and oxygen vacancies that quenched the extrinsic domain response to the dielectric constant. Barium borate fluxes were used to improve densification and crystallinity. Barium borate additions between 0 and 3% uniformly increased grain size and density, while levels greater than 3% resulted in anomalous grain growth. Films with exaggerated grains show tetragonal peak splitting in the X-ray diffraction patterns, consistent with bulk barium titanate. In materials without exaggerated grain growth, dielectric measurements revealed permittivities in excess of 3000 at room temperature (for average grain sizes of approximately 160 nm). This value is equivalent to the finest-prepared bulk ceramics and substantially greater than any polycrystalline film ever reported. This has been attributed to in improvement in film crystallinity. These two accomplishments - tetragonal crystal symmetry and permittivities in excess of 3000 - represent dramatic breakthroughs in ferroelectric thin film technology. (Abstract shortened by UMI.)

Ihlefeld, Jon Fredrick

399

TECHNICAL NOTE: The development of a PZT-based microdrive for neural signal recording  

NASA Astrophysics Data System (ADS)

A hand-controlled microdrive has been used to obtain neural signals from rodents such as rats and mice. However, it places severe physical stress on the rodents during its manipulation, and this stress leads to alertness in the mice and low efficiency in obtaining neural signals from the mice. To overcome this issue, we developed a novel microdrive, which allows one to adjust the electrodes by a piezoelectric device (PZT) with high precision. Its mass is light enough to install on the mouse's head. The proposed microdrive has three H-type PZT actuators and their guiding structure. The operation principle of the microdrive is based on the well known inchworm mechanism. When the three PZT actuators are synchronized, linear motion of the electrode is produced along the guiding structure. The electrodes used for the recording of the neural signals from neuron cells were fixed at one of the PZT actuators. Our proposed microdrive has an accuracy of about 400 nm and a long stroke of about 5 mm. In response to formalin-induced pain, single unit activities are robustly measured at the thalamus with electrodes whose vertical depth is adjusted by the microdrive under urethane anesthesia. In addition, the microdrive was efficient in detecting neural signals from mice that were moving freely. Thus, the present study suggests that the PZT-based microdrive could be an alternative for the efficient detection of neural signals from mice during behavioral states without any stress to the mice.

Park, Sangkyu; Yoon, Euisung; Lee, Sukchan; Shin, Hee-sup; Park, Hyunjun; Kim, Byungkyu; Kim, Daesoo; Park, Jongoh; Park, Sukho

2008-04-01

400

Development of a non-contact PZT excitation and sensing technology via laser  

NASA Astrophysics Data System (ADS)

In recent years, guided wave based structural health monitoring (SHM) techniques have attracted much attention, because they are not only sensitive to small defects but also capable to cover a wide range in plate and pipe like structures. The guided waves in a structure can be generated and sensed by a variety of techniques. This study proposes a new wireless scheme for PZT excitation and sensing where power as well as data can be transmitted via laser. A generated waveform by modulation of a laser is wirelessly transmitted to a photodiode connected to a PZT on the structures. Then, the photodiode converts the light into an electrical signal and excite the PZT and the structure. Then, the reflected response signal received at the sensing PZT is re-converted into a laser, which is wirelessly transmitted back to another photodiode located in the data acquisition unit for damage diagnosis. The feasibility of the proposed power and data transmission scheme has been experimentally investigated in a laboratory setup. Using the proposed technology, a PZT transducer can be attached to a structure without complex electronic components and a power supply.

Park, Hyun-Jun; Sohn, Hoon; Yun, Chung-Bang; Chung, Joseph; Lee, Michael

2011-04-01

401

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

PubMed Central

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

2012-01-01

402

Detrital zircon geochronologyof Carboniferous^ Cretaceousstratainthe Lhasaterrane,SouthernTibet  

E-print Network

of Arizona,Tucson, AZ, USA ABSTRACT Sedimentary strata in the Lhasa terrane of southernTibet record a long Palaeozoic and Mesozoic sedimentary rocks in the Lhasa terrane for detrital zircon uranium^lead (U zircon data set from the Lhasa terrane and shed new light on the tectonic and depositional history

403

Reaction, transformation and delamination of samarium zirconate thermal barrier coatings  

E-print Network

Reaction, transformation and delamination of samarium zirconate thermal barrier coatings Hengbei zirconates have attracted interest for thermal barrier coatings (TBCs) because they have very low intrinsic.V. All rights reserved. 1. Introduction Thermal barrier coating (TBC) systems are an enabling materials

Wadley, Haydn

404

Vapor deposited samarium zirconate thermal barrier coatings Hengbei Zhao a,  

E-print Network

Vapor deposited samarium zirconate thermal barrier coatings Hengbei Zhao a, , Carlos G. Levi b form 24 March 2009 Available online 1 April 2009 Keywords: Samarium zirconate Directed-vapor deposition applications. An electron-beam evaporation, directed-vapor deposition (EB-DVD) technique has been used

Wadley, Haydn

405

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

406

Condensation of Ices 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 at the colder temperatures of Titan's mid to lower stratosphere. Stratospheric ices can contribute to the opacity of Titan's atmosphere as well as affect the chemistry of the more optically thick clouds seen in the troposphere, should they survive long enough to serve as condensation nuclei. There are a number of observations from both Cassini and Voyager data that point to the condensation of trace species in Titan’s atmosphere, including HCN, C2H5CN, HC3N, C2H2, C2H6, and C4N2. These and about a dozen other species have now been added to the Titan CARMA microphysics model, which shows condensation occurring between 50 and 100 km in Titan's atmosphere. Results on condensation altitudes as well as particle size will be presented, and implications for the optical properties of Titan's stratospheric aerosol particles will be discussed.

Barth, Erika L.

2014-11-01

407

A wind origin for Titan's haze structure  

Microsoft Academic Search

Titan, the largest moon of Saturn, is the only satellite in the Solar System with a dense atmosphere. Titan's atmosphere is mainly nitrogen with a surface pressure of 1.5atmospheres and a temperature of 95K (ref. 1). A seasonally varying haze, which appears to be the main source of heating and cooling that drives atmospheric circulation, shrouds the moon. The haze

P. Rannou; F. Hourdin; C. P. McKay

2002-01-01

408

A new look at Titan's atmospheric system  

Microsoft Academic Search

A wealth of observations of Titan's atmosphere have been acquired since July 2004 by the Cassini spacecraft and during the Huygens entry and descent on January 14, 2005. Complemented with Earth-based observations obtained in the last decade, they provide us with a new view of Titan's atmosphere, with essential results on its thermal, compositional, and dynamical aspects. These results and

E. Lellouch

2005-01-01

409

Three-Dimensional Views of Titan  

Microsoft Academic Search

By the end of its four-year prime mission, Cassini obtained 300-1500 m resolution synthetic aperture radar images of the surface of Titan during 19 flybys, with ~2% of the surface imaged two or more times. Most image pairs have different viewing directions, and thus contain stereo parallax that encodes information about Titan's surface relief over distances of ~1 km and

R. L. Kirk; E. Howington-Kraus; B. L. Redding; T. L. Becker; E. M. Lee; B. W. Stiles; S. Hensley

2009-01-01

410

Congratulations to the 2011 Tech Titan Recipients  

E-print Network

hardware and software applications that are used by business and individuals in today's fast paced world participation. A live auction also was held to raise additional funds for the scholarship fund for Tech Titans signed by the mayors of cities in the DFW region represented by Tech Titan and FastTech companies

Chiao, Jung-Chih

411

Cassini Radar Views the Surface of Titan  

Microsoft Academic Search

The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of ~0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with

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

2005-01-01

412

Using Titanic to Teach Earth Science  

Microsoft Academic Search

The Houston Museum of Natural Science is producing a unique planetarium documentary called Night of the Titanic. The program uses full-dome simulations to recreate the environment in the North Atlantic off the Newfoundland Coast on April 14, 1912 and to show the complex series of natural and human events that sank the ``unsinkable'' ship. Night of the Titanic is a

C. Sumners; T. S. Ledley; P. H. Reiff

2002-01-01

413

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

414

Reactive sintering of plutonium-bearing titanates.  

SciTech Connect

Titanate ceramics are being developed for the immobilization of weapons-grade plutonium. These multi-phase ceramics are intended to be both corrosion and proliferation resistant. Reactive sintering techniques were refined to reproducibly provide titanate ceramics for further characterization and testing. Plutonium-bearing pyrochlore-rich composites were consolidated to greater than 90% of their theoretical density.

Hash, M. C.

1999-06-24

415

Zircon Thermometer Reveals Minimum Melting Conditions on Earliest Earth  

NASA Astrophysics Data System (ADS)

Ancient zircons from Western Australia's Jack Hills preserve a record of conditions that prevailed on Earth not long after its formation. Widely considered to have been a uniquely violent period geodynamically, the Hadean Eon [4.5 to 4.0 billion years ago (Ga)] has recently been interpreted by some as far more benign-possibly even characterized by oceans like those of the present day. Knowledge of the crystallization temperatures of the Hadean zircons is key to this debate. A thermometer based on titanium content revealed that these zircons cluster strongly at ~700°C, which is indistinguishable from temperatures of granitoid zircon growth today and strongly suggests a regulated mechanism producing zircon-bearing rocks during the Hadean. The temperatures substantiate the existence of wet, minimum-melting conditions within 200 million years of solar system formation. They further suggest that Earth had settled into a pattern of crust formation, erosion, and sediment recycling as early as 4.35 Ga.

Watson, E. B.; Harrison, T. M.

2005-05-01

416

INTEGRATING SOLUTION-DERIVED 3D PZT STRUCTURES ON Si MEMS PLATFORM FOR RF AND BIOMEDICAL APPLICATIONS  

E-print Network

INTEGRATING SOLUTION-DERIVED 3D PZT STRUCTURES ON Si MEMS PLATFORM FOR RF AND BIOMEDICAL33 resulting in lower electromechanical performance. Integrating vertical PZT structures in Si can with 2D integration. 3D ceramic structures are also useful for increasing the capacitance density

Ayazi, Farrokh

417

Ralph D. Lorenz Post-Cassini Exploration of Titan: Science  

E-print Network

218 Ralph D. Lorenz Post-Cassini Exploration of Titan: Science Rationale and Mission Concepts RALPH scientific questions posed by Titan after the upcoming Cassini mission, and the engineering issues associated of Titans environment, and would satisfy the broadest range of scientific objectives. 1. Introduction Titan

Lorenz, Ralph D.

418

34 McCormick / spring Lead mechanical engineer, Titan Aerospace  

E-print Network

34 McCormick / spring Dan Cornew Lead mechanical engineer, Titan Aerospace Mechanical engineeringCormick: What does Titan Aerospace do? Cornew: Titan Aerospace is a startup that designs and builds solar is Titan's founder, was looking for someone with experience in aero- space and solar power. I had interned

Chen, Wei

419

Rivers, Lakes, Dunes, and Rain: Crustal Processes in Titan's  

E-print Network

Rivers, Lakes, Dunes, and Rain: Crustal Processes in Titan's Methane Cycle Jonathan I. Lunine1-6597/09/0530-0299$20.00 Key Words hydrology, climate, hydrocarbons, atmospheres, planets, clouds Abstract Titan exhibits ample SETTING FOR A METHANE CYCLE ON TITAN Titan is Saturn's largest natural satellite and the second

Reiners, Peter W.

420

GANYMEDE, TITAN & MARTIAN ASTR/GEOL 5800 Planetary Surfaces & Interiors  

E-print Network

GANYMEDE, TITAN & MARTIAN MOONS ASTR/GEOL 5800 Planetary Surfaces & Interiors 03 December 2013 #12 are probably the result of Ganymede's capture into resonance (~2 Gyr B.P.) #12;Titan #12;Why is Titan important cycle" predicted · Exploration ­ Cassini/Huygens Titan M E T D R. T H I P #12;Basic Parameters · Only

Mojzsis, Stephen J.

421

Imaging of Titan from the Cassini Carolyn C. Porco1  

E-print Network

Imaging of Titan from the Cassini spacecraft Carolyn C. Porco1 , Emily Baker1 , John Barbara2 ........................................................................................................................................................................................................................... Titan, the largest moon of Saturn, is the only satellite in the Solar System with a substantial about Titan's nature. Here we present observations of Titan from the imaging science experiment onboard

422

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

423

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

424

Titan Orbiter with Aerorover Mission (TOAM)  

NASA Technical Reports Server (NTRS)

We propose to develop a new mission to Titan called Titan Orbiter with Aerorover Mission (TOAM). This mission is motivated by the recent discoveries of Titan, its atmosphere and its surface by the Huygens Probe, and a combination of in situ, remote sensing and radar mapping measurements of Titan by the Cassini orbiter. Titan is a body for which Astrobiology (i.e., prebiotic chemistry) will be the primary science goal of any future missions to it. TOAM is planned to use an orbiter and balloon technology (i.e., aerorover). Aerobraking will be used to put payload into orbit around Titan. One could also use aerobraking to put spacecraft into orbit around Saturn first for an Enceladus phase of the mission and then later use aerocapture to put spacecraft into orbit around Titan. The Aerorover will probably use a hot air balloon concept using the waste heat from the MMRTG approx. 1000 watts. Orbiter support for the Aerorover is unique to our approach for Titan. Our strategy to use an orbiter is contrary to some studies using just a single probe with balloon. Autonomous operation and navigation of the Aerorover around Titan will be required, which will include descent near to the surface to collect surface samples for analysis (i.e., touch and go technique). The orbiter can provide both relay station and GPS roles for the Aerorover. The Aerorover will have all the instruments needed to sample Titan's atmosphere, surface, possible methane lakes-rivers, use multi-spectral imagers for surface reconnaissance; to take close up surface images; take core samples and deploy seismometers during landing phase. Both active and passive broadband remote sensing techniques will be used for surface topography, winds and composition measurements.

Sittler, E. C., Jr.; Cooper, J. F.; Mahaffy, P.; Esper, J.; Fairbrother, D.; Farley, R.; Pitman, J.; Kojiro, D. R.; Acuna, M.; Allen, M.; Bjoraker, G.; Brasunas, J.; Farrell, W.; Burchell, M. J.; Burger, M.; Chin, G.; Coates, A. J.; Farrell, W.; Flasar, M.; Gerlach, B.; Gorevan, S.; Hartle, R. E.; Im, Eastwood; Jennings, D.; Johnson, R. E.

2007-01-01

425

Auroral electron precipitation and flux tube erosion in Titan’s upper atmosphere  

NASA Astrophysics Data System (ADS)

Cassini dasta shows that Titan’s atmosphere strongly depletes the electron content in Saturn’s flux tubes, producing features known as electron bite-outs, which indicate that the flux of auroral electrons decreases over time. To understand this process we have developed a time-dependent two-stream model, which uses field line geometries and drift paths calculated by a three-dimensional multi-fluid model of Titan’s plasma interaction. The boundary conditions of the model account for the time-dependent reduction or increase in electron flux along Saturn’s magnetic field lines because of the loss or production of electrons in Titan’s atmosphere. The modification of the auroral electron flux depends on the electron bounce period in Saturn’s outer magnetosphere; therefore, we also calculate electron bounce periods along several Kronian field lines accounting for both the magnetic mirroring force and the field-aligned electric potential in Saturn’s plasma sheet. We use the time-dependent two-stream model to calculate how the reduction in the auroral electron flux affects electron impact ionization and energy deposition rates in Titan’s upper atmosphere. We find that the flux of higher energy (>50 eV) electrons entering Titan’s atmosphere is strongly reduced over time, resulting in smaller ionization and energy deposition rates below ?1300 km altitude. Finally, we show that sample spectrograms produced from our calculations are consistent with CAPS-ELS data.

Snowden, D.; Yelle, R. V.; Galand, M.; Coates, A. J.; Wellbrock, A.; Jones, G. H.; Lavvas, P.

2013-09-01

426

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

427

Planning for post-Cassini/HuygensPlanning for post-Cassini/Huygens Exploration of Titan:Exploration of Titan  

E-print Network

Planning for post-Cassini/HuygensPlanning for post-Cassini/Huygens Exploration of Titan:Exploration of Titan: Laboratory Studies of anLaboratory Studies of an AstrobiologicalAstrobiological Hot SpotHot Spot, Department of Chemistry, U of A Chris Welch, Merck and Co. #12;TitanTitan · is Saturn's largest moon

Beauchamp, Jack

428

Greetings Titan Parents and Family Members! I would like to welcome you once more to the Titan  

E-print Network

Greetings Titan Parents and Family Members! I would like to welcome you once more to the Titan with helpful information and useful tools, we have developed our first parent newsletter, Titan Parent are Kandy Mink Salas, Dean of Students Welcome New Titan Parents! A Message from our Dean of Students INSIDE

de Lijser, Peter

429

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

430

Piezoelectric AlN and PZT films for micro-electronic applications  

Microsoft Academic Search

Piezoelectric AlN and PbZrxTi1-xO3 (PZT) layers are investigated with respect to their potential for HF micro-electronic applications. High quality AlN films with strong c-axis orientation are achieved by optimum deposition conditions and by applying nucleation layers. Electromechanical coupling factors of 0.25±0.03 have been found. PZT films grown via sol-gel processing show high coupling factors k of 0.4-0.6 and are therefore

H. P. Lobl; M. Klee; O. Wunnicke; R. Kiewitt; R. Dekker; E. V. Pelt

1999-01-01

431

Orientation control and electrical properties of PZT\\/LNO capacitor through chemical solution deposition  

Microsoft Academic Search

This paper describes the deposition of PZT\\/lanthanum nickel oxide (LNO) electrode thin-film capacitor on a Si(100) substrate with a chemical solution deposition (CSD). Highly (100)-oriented LNO film with a perovskite structure was deposited by annealing at 700°C from a precursor solution of La(NO3)3 and Ni(CH3COO)2. In addition, highly (100)&(001)-oriented PZT\\/LNO capacitor was deposited on LNO\\/Si substrate by annealing at 600°C,

H. Suzuki; Y. Miwa; T. Naoe; H. Miyazaki; T. Ota; M. Fuji; M. Takahashi

2006-01-01

432

Zirconia (NC) zircon as a potential standard  

NASA Astrophysics Data System (ADS)

As microanalysis continues to advance and become more widespread there is a greater need for abundant and suitable age standards. Megacrystic zircons from the inactive Freeman Mine near Zirconia, NC were collected from weathered mine dump piles. Zirconia zircon crystals are large (> 1 mm) relative to typical zircons (up to 100s ?m) and easily obtained; attributes that make them attractive as a potential standard. We present here preliminary data and assess the suitability of Zirconia zircons as a U-Pb geochronology, Hf-isotope and trace-element standard. Grains are variably fluorescent (Callahan et al, Southeastern Geol., 2007), and we used shortwave fluorescence to separate grains with high, medium, low/no fluorescence from one another. Images were taken of the grains before mounting and post-polishing to understand the fluorescence characterization of the surface to the core. After preparing the grains, we found that the fluorescence was not homogenous and did not provide a good means of separating out grains. In order to investigate the differences in fluorescence, we collected cathodoluminescence (CL) and backscatter electron (BSE) images and energy dispersive spectroscopy (EDS) maps using a Tescan Vega 3 LMU equipped with an Oxford X-max 50 mm2 solid-state EDS detector at Vanderbilt University. This allowed division of the grains into two types: (a) grains with finely oscillatory zoned rims, which are variably crosscut by dull-CL irregular zones, sometimes showing hourglass zoning; and (b) grains with cores showing more irregular, patchy zoning with and without thin oscillatory rims. EDS maps show no major element zoning in the zircon grains, but reveal a variety of inclusions, particularly of quartz and thorite. Preliminary U-Pb ages were obtained using a Perkin Elmer Elan DRCII ICP-MS coupled with a New Wave/Mechantek 213 nm Nd:YAG laser ablation system at Vanderbilt University. A total of ~150 individual ages on oscillatory-zoned (Type a) crystals yield a Concordia age of 329 ± 1 Ma. Type b grains yield less reliable results and have not been extensively studied. A small number of SHRIMP U-Pb ages were obtained at the Stanford USGS Micro Analysis Center using a SHRIMP-RG, and yield an age of 327 ± 2 Ma. Prelim