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https://www.readbyqxmd.com/read/28508876/post-supereruption-recovery-at-toba-caldera
#1
Adonara E Mucek, Martin Danišík, Shanaka L de Silva, Axel K Schmitt, Indyo Pratomo, Matthew A Coble
Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28453970/on-chip-ultrasonic-manipulation-of-microparticles-by-using-the-flexural-vibration-of-a-glass-substrate
#2
Ryota Yamamoto, Daisuke Koyama, Mami Matsukawa
As biotechnology develops, techniques for manipulating and separating small particles such as cells and DNA are required in the life sciences. This paper investigates on-chip manipulation of microparticles in small channels by using ultrasonic vibration. The chip consists of a rectangular glass substrate with a cross-shaped channel (cross-section: 2.0×2.0mm(2)) and four lead zirconate titanate transducers attached to the substrate's four corners. To efficiently generate the flexural vibration mode on the chip, we used finite element analysis to optimize the configurations of the glass substrate and transducers...
December 15, 2016: Ultrasonics
https://www.readbyqxmd.com/read/28436860/effect-on-high-intensity-fields-of-a-tough-hydrophone-with-hydrothermal-pzt-thick-film-vibrator-and-titanium-front-layer
#3
Nagaya Okada, Shinichi Takeuchi
A novel tough hydrophone was fabricated by depositing hydrothermally synthesized lead zirconate titanate polycrystalline film on the back-side surface of a titanium plate. Our developed tough hydrophone resisted damage in a high-pressure field (15 MPa) at a focal point of a sinusoidal continuous wave driven by a concave high-intensity focused ultrasound (HIFU) transducer with up to 50 W of power input to the sound source. The hydrophone was suitable for the HIFU field, even though the hydrophone has a flat-shape tip of 3...
April 24, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28425964/enhancing-the-responsivity-of-uncooled-infrared-detectors-using-plasmonics-for-high-performance-infrared-spectroscopy
#4
Amr Shebl Ahmed, Hye Jin Kim, Jinsik Kim, Kyo Seon Hwang, Seonghwan Kim
A lead zirconate titanate (PZT;Pb(Zr0.52Ti0.48)O₃) layer embedded infrared (IR) detector decorated with wavelength-selective plasmonic crystals has been investigated for high-performance non-dispersive infrared (NDIR) spectroscopy. A plasmonic IR detector with an enhanced IR absorption band has been designed based on numerical simulations, fabricated by conventional microfabrication techniques, and characterized with a broadly tunable quantum cascade laser. The enhanced responsivity of the plasmonic IR detector at specific wavelength band has improved the performance of NDIR spectroscopy and pushed the limit of detection (LOD) by an order of magnitude...
April 20, 2017: Sensors
https://www.readbyqxmd.com/read/28425542/acceptor-doping-in-the-proton-conductor-srzro3
#5
Leigh Weston, A Janotti, X Y Cui, C Stampfl, C G Van de Walle
Perovskite zirconates such as SrZrO3 exhibit improved proton solubility and conductivity when doped with trivalent cations substituting at the Zr site. In this work, we present a detailed study of Sc and Y dopants in SrZrO3 based on first-principles, hybrid density-functional calculations. When substituting at the Zr site (ScZr, YZr), both dopants give rise to a single, deep acceptor level, where the neutral impurity forms a localized hole polaron state. The ε(0/-) charge transition levels are 0.60 eV and 0...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28400602/first-direct-evidence-of-pan-african-orogeny-associated-with-gondwana-assembly-in-the-cathaysia-block-of-southern-china
#6
Longming Li, Shoufa Lin, Guangfu Xing, Yang Jiang, Jian He
Metamorphic zircon from a hornblendite in the South China Block (SCB) yield U-Pb age of 533 ± 7 Ma and Hf model ages from 900 to 1200 Ma. Geochemical and isotopic characteristics indicate that primary magma of the hornblendites was probably derived from an enriched asthenospheric mantle source. This Late Neoproterozoic-Cambrian (Pan-African) metamorphic event provides the first direct evidence that the SCB was an integral part of the Gondwana assembly. Combined with available geological data which show that the SCB has great affinity with India or Australia, the Pan-African metamorphic event most likely belongs to the eastern Kuunga orogeny...
April 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28389635/contrasting-granite-metallogeny-through-the-zircon-record-a-case-study-from-myanmar
#7
Nicholas J Gardiner, Chris J Hawkesworth, Laurence J Robb, Martin J Whitehouse, Nick M W Roberts, Christopher L Kirkland, Noreen J Evans
Granitoid-hosted mineral deposits are major global sources of a number of economically important metals. The fundamental controls on magma metal fertility are tectonic setting, the nature of source rocks, and magma differentiation. A clearer understanding of these petrogenetic processes has been forged through the accessory mineral zircon, which has considerable potential in metallogenic studies. We present an integrated zircon isotope (U-Pb, Lu-Hf, O) and trace element dataset from the paired Cu-Au (copper) and Sn-W (tin) magmatic belts in Myanmar...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28371521/spray-dried-sodium-zirconate-a-rapid-absorption-powder-for-co2-capture-with-enhanced-cyclic-stability
#8
Faith Bamiduro, Guozhao Ji, Andy P Brown, Valerie A Dupont, Ming Zhao, Steven J Milne
Improved powders for capturing CO2 at high temperatures are required for H2 production using sorption-enhanced steam reforming. Here, we examine the relationship between particle structure and carbonation rate for two types of Na2 ZrO3 powders. Hollow spray-dried microgranules with a wall thickness of 100-300 nm corresponding to the dimensions of the primary acetate-derived particles gave about 75 wt % theoretical CO2 conversion after a process-relevant 5 min exposure to 15 vol % CO2 . A conventional powder prepared by solid-state reaction carbonated more slowly, achieving only 50 % conversion owing to a greater proportion of the reaction requiring bulk diffusion through the densely agglomerated particles...
April 3, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28349169/multispectroscopic-methodology-to-study-libyan-desert-glass-and-its-formation-conditions
#9
Leticia Gomez-Nubla, Julene Aramendia, Silvia Fdez-Ortiz de Vallejuelo, Ainhoa Alonso-Olazabal, Kepa Castro, Maria Cruz Zuluaga, Luis Ángel Ortega, Xabier Murelaga, Juan Manuel Madariaga
Libyan desert glass (LDG) is a melt product whose origin is still a matter of controversy. With the purpose of adding new information about this enigma, the present paper analyzes the inner part of LDG specimens and compares them with the results of LDG surfaces. An integrated analytical methodology was used combining different techniques such as Raman spectroscopy, in point-by-point and imaging modes, scanning electron microscopy with X-ray microanalysis (SEM-EDS), energy-dispersive micro X-ray fluorescence spectrometry (μ-EDXRF), electron probe micro analyzer (EPMA), and optical cathodoluminescence (Optical-CL)...
March 27, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28345655/large-electrocaloric-effect-in-relaxor-ferroelectric-and-antiferroelectric-lanthanum-doped-lead-zirconate-titanate-ceramics
#10
Biao Lu, Peilian Li, Zhenhua Tang, Yingbang Yao, Xingsen Gao, Wolfgang Kleemann, Sheng-Guo Lu
Both relaxor ferroelectric and antiferroelectric materials can individually demonstrate large electrocaloric effects (ECE). However, in order to further enhance the ECE it is crucial to find a material system, which can exhibit simultaneously both relaxor ferroelectric and antiferroelectric properties, or easily convert from one into another in terms of the compositional tailoring. Here we report on a system, in which the structure can readily change from antiferroelectric into relaxor ferroelectric and vice versa...
March 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28345044/continental-igneous-rock-composition-a-major-control-of-past-global-chemical-weathering
#11
Clément P Bataille, Amy Willis, Xiao Yang, Xiao-Ming Liu
The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [((87)Sr/(86)Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of ((87)Sr/(86)Sr)seawater variations to the strontium isotopic composition ((87)Sr/(86)Sr) in igneous rocks generated through time...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28338853/radiological-impacts-assessment-for-workers-in-ceramic-industry-in-serbia
#12
Nataša Todorovic, Dušan Mrda, Jan Hansman, Slavko Todorovic, Jovana Nikolov, Miodrag Krmar
Studies have been carried out to determine the natural radioactivity in some materials used in ceramic industry (zircon, zirkosil, Zircobit MO/S, zircon silicate, zirklonil frit, hematite, bentonite, wollastonite, raw kaolin, kaolinized granite, sileks ball, feldspar, pigment, white base serigraphic, engobe) and their associated radiation hazard. The external hazard index, Hex, values, radium equivalent activity, Raeq, total absorbed dose rates, D and annual effective dose, De were derived for all measured materials and compared with the recommended values to assess the external radiation hazards to workers who worked in ceramic industries in Serbia...
March 3, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28333626/temperature-dependence-of-domain-contributions-as-a-function-of-ageing-in-soft-and-hard-lead-zirconate-titanate-piezoelectric-ceramics
#13
Sayyed A Qaisar, Timothy P Comyn, Andrew J Bell
The stress and temperature dependence of three different PZT ceramics have been measured at 48 hours and 1 month after poling. The data were fitted to a modified Rayleigh law in which a negative quadratic stress term accounts for a saturation of the domain wall contributions at higher stress. The relative changes to the fitting parameters can be explained by the materials possessing differences in the concentration of orientable defect dipoles, but with similar distributions of relaxation time constants.
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28325934/cordillera-zealandia-a-mesozoic-arc-flare-up-on-the-palaeo-pacific-gondwana-margin
#14
L A Milan, N R Daczko, G L Clarke
Two geochemically and temporally distinct components of the Mesozoic Zealandia Cordilleran arc indicate a shift from low to high Sr/Y whole rock ratios at c. 130 Ma. Recent mapping and a reappraisal of published Sr-Nd data combined with new in-situ zircon Hf isotope analyses supports a genetic relationship between the two arc components. A reappraisal of geophysical, geochemical and P-T estimates demonstrates a doubling in thickness of the arc to at least 80 km at c. 130 Ma. Contemporaneously, magmatic addition rates shifted from ~14 km(3)/my per km of arc to a flare-up involving ~100 km(3)/my per km of arc...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28325908/tuning-of-large-piezoelectric-response-in-nanosheet-buffered-lead-zirconate-titanate-films-on-glass-substrates
#15
Anuj Chopra, Muharrem Bayraktar, Maarten Nijland, Johan E Ten Elshof, Fred Bijkerk, Guus Rijnders
Renewed interest has been witnessed in utilizing the piezoelectric response of PbZr0.52Ti0.48O3 (PZT) films on glass substrates for applications such as adaptive optics. Accordingly, new methodologies are being explored to grow well-oriented PZT thin films to harvest a large piezoelectric response. However, thin film piezoelectric response is significantly reduced compared to intrinsic response due to substrate induced clamping, even when films are well-oriented. Here, a novel method is presented to grow preferentially (100)-oriented PZT films on glass substrates by utilizing crystalline nanosheets as seed layers...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28282968/temporal-and-structural-evolution-of-the-early-pal%C3%A3-ogene-rocks-of-the-seychelles-microcontinent
#16
J Gregory Shellnutt, Meng-Wan Yeh, Kenshi Suga, Tung-Yi Lee, Hao-Yang Lee, Te-Hsien Lin
The Early Palæogene Silhouette/North Island volcano-plutonic complex was emplaced during the rifting of the Seychelles microcontinent from western India. The complex is thought to have been emplaced during magnetochron C28n. However, the magnetic polarities of the rocks are almost entirely reversed and inconsistent with a normal polarity. In this study we present new in situ zircon U/Pb geochronology of the different intrusive facies of the Silhouette/North Island complex in order to address the timing of emplacement and the apparent magnetic polarity dichotomy...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28273880/5-v-compatible-two-axis-pzt-driven-mems-scanning-mirror-with-mechanical-leverage-structure-for-miniature-lidar-application
#17
Liangchen Ye, Gaofei Zhang, Zheng You
The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V...
March 5, 2017: Sensors
https://www.readbyqxmd.com/read/28257006/solid-state-nmr-and-short-range-order-in-crystalline-oxides-and-silicates-a-new-tool-in-paramagnetic-resonances
#18
Jonathan F Stebbins, Ryan J McCarty, Aaron C Palke
Most applications of high-resolution NMR to questions of short-range order/disorder in inorganic materials have been made in systems where ions with unpaired electron spins are of negligible concentration, with structural information extracted primarily from chemical shifts, quadrupolar coupling parameters, and nuclear dipolar couplings. In some cases, however, the often-large additional resonance shifts caused by interactions between unpaired electron and nuclear spins can provide unique new structural information in materials with contents of paramagnetic cations ranging from hundreds of ppm to several per cent and even higher...
March 1, 2017: Acta Crystallographica. Section C, Structural Chemistry
https://www.readbyqxmd.com/read/28247756/strongly-enhanced-piezoelectric-response-in-lead-zirconate-titanate-films-with-vertically-aligned-columnar-grains
#19
Minh D Nguyen, Evert P Houwman, Matthijn Dekkers, Guus Rijnders
Pb(Zr0.52Ti0.48)O3 (PZT) films with (001) orientation were deposited on Pt(111)/Ti/SiO2/Si(100) substrates using pulsed laser deposition. Variation of the laser pulse rate during the deposition of the PZT films was found to play a key role in the control of the microstructure and to change strongly the piezoelectric response of the thin film. The film deposited at low pulse rate has a denser columnar microstructure, which improves the transverse piezoelectric coefficient (d31f) and ferroelectric remanent polarization (Pr), whereas the less densely packed columnar grains in the film deposited at high pulse rates give rise to a significantly higher longitudinal piezoelectric coefficient (d33f) value...
March 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28246632/seeing-is-believing-visualization-of-he-distribution-in-zircon-and-implications-for-thermal-history-reconstruction-on-single-crystals
#20
Martin Danišík, Brent I A McInnes, Christopher L Kirkland, Brad J McDonald, Noreen J Evans, Thomas Becker
Zircon (U-Th)/He thermochronometry is an established radiometric dating technique used to place temporal constraints on a range of thermally sensitive geological events, such as crustal exhumation, volcanism, meteorite impact, and ore genesis. Isotopic, crystallographic, and/or mineralogical heterogeneities within analyzed grains can result in dispersed or anomalous (U-Th)/He ages. Understanding the effect of these grain-scale phenomena on the distribution of He in analyzed minerals should lead to improvements in data interpretation...
February 2017: Science Advances
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