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Pham Ngoc Thao, Shinya Yoshida, Shuji Tanaka
This paper presents a fibered-epitaxial lead zirconate titanate (PZT) thin film with intermediate features between the monocrystalline and polycrystalline thin films for piezoelectric micromachined ultrasound transducer (pMUT). The grain boundaries confirmed by scanning electron microscopy, but it still maintained the in-plane epitaxial relationship found by X-ray diffraction analyses. The dielectric constant ( εr 33 = 500) was relatively high compared to those of the monocrystalline thin films, but was lower than those of conventional polycrystalline thin films near the morphotropic phase boundary composition...
September 11, 2018: Micromachines
Hussain Altammar, Anoop Dhingra, Nathan Salowitz
Ultrasonic systems employing embedded piezoelectric transducers have seen increased interest in recent years. The ability to sense, actuate, and analyze the wave propagation modes in engineering structures has been fundamental to the advancement of ultrasonic structural health monitoring (SHM). This paper presents a study into the sensing and actuation properties of shear-mode (d35) piezoelectric transducers made of lead zirconate titanate (PZT) that are internally embedded in the bondline of laminate structures...
November 11, 2018: Sensors
Liliana Londoño, Dana L Royer, Carlos Jaramillo, Jaime Escobar, David A Foster, Andrés L Cárdenas-Rozo, Aaron Wood
PREMISE OF THE STUDY: The global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO2 records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate. METHODS: In this study, we use a leaf gas-exchange model to estimate CO2 concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18...
November 12, 2018: American Journal of Botany
Jon J Smith, Elijah Turner, Andreas Möller, R M Joeckel, Rick E Otto
This paper documents the first U-Pb zircon ages for Ashfall Fossil Beds (Nebraska, USA), a terrestrial Konservat-Lagerstätte mass-death assemblage that is arguably the most diverse of its type and age. The Ashfall tephra was correlated with ignimbrites from the Bruneau-Jarbidge volcanic field (12.7-10.5 Ma) in southwest Idaho based on geochemical analysis. The methods and geochemical data supporting the original age assessment of the ash bed, however, were never published, and there has been a persistent misconception that dateable heavy minerals (e...
2018: PloS One
Raymond J E Hueting
For some years now, the ever continuing dimensional scaling has no longer been considered to be sufficient for the realization of advanced CMOS devices. Alternative approaches, such as employing new materials and introducing new device architectures, appear to be the way to go forward. A currently hot approach is to employ ferroelectric materials for obtaining a positive feedback in the gate control of a switch. This work elaborates on two device architectures based on this approach: the negative-capacitance and the piezoelectric field-effect transistor, i...
November 7, 2018: Micromachines
Yebo Liu, Zheng-Xiang Li, Sergei A Pisarevsky, Uwe Kirscher, Ross N Mitchell, J Camilla Stark, Chris Clark, Martin Hand
A pilot palaeomagnetic study was conducted on the recently dated with in situ SHRIMP U-Pb method at 1134 ± 9 Ma (U-Pb, zircon and baddeleyite) Bunger Hills dykes of the Mawson Craton (East Antarctica). Of the six dykes sampled, three revealed meaningful results providing the first well-dated Mesoproterozoic palaeopole at 40.5°S, 150.1°E (A95  = 20°) for the Mawson Craton. Discordance between this new pole and two roughly coeval poles from Dronning Maud Land and Coats Land (East Antarctica) demonstrates that these two terranes were not rigidly connected to the Mawson Craton ca...
November 6, 2018: Scientific Reports
Yabin Liang, Qian Feng, Dongsheng Li, Sijia Cai
Threaded connections are the most common pipe fittings used in oil and gas transportation systems. Due to external vibrations, cyclic loads, and pollution, the fitting parts may start getting loose, which could result in pipeline leaks and other environmental disasters. It is of great significance to develop a reliable technique that could provide real-time monitoring of the looseness of pipeline fittings. In this paper, a piezoceramic-based active sensing method combined with the electro-mechanical impedance (EMI) technique was developed to monitor the health condition of threaded pipe connections in real time...
October 30, 2018: Sensors
Javier Ruiz-Fuertes, Domingo Martínez-García, Tomás Marqueño, Daniel Errandonea, Simon G MacLeod, Thomas Bernert, Eiken Haussühl, David Santamaría-Pérez, Jordi Ibáñez, Anitha Mallavarapu, S Nagabhusan Achary, Catalin Popescu, Marco Bettinelli
The zircon to scheelite phase boundary of ErVO4 has been studied by high-pressure and high-temperature powder and single-crystal X-ray diffraction. This study has allowed us to delimit the best synthesis conditions of its scheelite-type phase, determine the ambient-temperature equation of state of the zircon and scheelite-type structures, and obtain the thermal equation of state of the zircon-type polymorph. The results obtained with powder samples indicate that zircon-type ErVO4 transforms to scheelite at 8...
November 5, 2018: Inorganic Chemistry
Lutz Nasdala, Shavkat Akhmadaliev, Andreas Artac, Chutimun Chanmuang N, Gerlinde Habler, Christoph Lenz
Lamellae of 1.5 µm thickness, prepared from well-crystallised monazite-(Ce) and zircon samples using the focused-ion-beam technique, were subjected to triple irradiation with 1 MeV Au+ ions (15.6% of the respective total fluence), 4 MeV Au2+ ions (21.9%) and 10 MeV Au3+ ions (62.5%). Total irradiation fluences were varied in the range 4.5 × 1012  - 1.2 × 1014 ions/cm2 . The highest fluence resulted in amorphisation of both minerals; all other irradiations (i.e. up to 4.5 × 1013 ions/cm2 ) resulted in moderate to severe damage...
2018: Physics and Chemistry of Minerals
Anthony I S Kemp
Many studies link the presence of continents on Earth to the operation of plate tectonics. Radiogenic isotope data have, however, long consigned the bulk of crust generation and preservation to the murky realm of the Precambrian Earth, where the prevailing geodynamic systems are highly uncertain due to the sparse and complex nature of the geological record of these early eons. The purpose of this paper is to examine the nature of this geological record, considering the biases and artefacts that may undermine its fidelity, and to assess what are the most robust lines of evidence from which meaningful geodynamic inferences can be drawn...
October 1, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Andrés López-Vásquez, Pilar Delgado-Niño, Donaldo Salas-Siado
The aim of the present research was to study the photocatalytic activity under UV/visible irradiation of the ceramic compound Sr0.97 Eu0.02 Zr0.1 Ti0.9 O3 (SEZT1) using ethylenediaminetetraacetic acid (EDTA) as a sacrificial agent to produce H2 . The effects of the reaction parameters such as pH, the initial concentration of the sacrificial agent, and the amount of photocatalyst were systematically investigated through response surface methodology. The results showed that the photocatalytic performance was strongly affected by higher levels of sacrificial agent concentration (70...
September 26, 2018: Environmental Science and Pollution Research International
Deng-Fei Duan, Shao-Yong Jiang
The data in this article contains major, trace and rare earth element concentrations of apatite, and statistic analysis of apatite morphology in the granitoid rocks from the Edong ore district, South China, together with zircon U-Pb dating results for these rocks. Both the ore-associated and barren granitoids yield similar ages, including quartz diorite in the Fuzishan Cu-Au skarn deposit (138.6 ± 2.9 Ma), quartz monzodiorite in the Niutoushan Cu skarn deposit (137.8 ± 1.8 Ma), quartz diorite in the Ouyangshan Cu skarn deposit (138...
October 2018: Data in Brief
Jennifer Kasbohm, Blair Schoene
Flood basalts, the largest volcanic events in Earth history, are thought to drive global environmental change because they can emit large volumes of CO2 and SO2 over short geologic time scales. Eruption of the Columbia River Basalt Group (CRBG) has been linked to elevated atmospheric CO2 and global warming during the mid-Miocene climate optimum (MMCO) ~16 million years (Ma) ago. However, a causative relationship between volcanism and warming remains speculative, as the timing and tempo of CRBG eruptions is not well known...
September 2018: Science Advances
Yuan Zeng, Feng Liang, Jianghao Liu, Jun Zhang, Haijun Zhang, Shaowei Zhang
To address the various shortcomings of a high material cost, energy-intensive temperature conditions and ultra-low efficiency of the conventional boro/carbothermal reduction method for the industrial preparation of ZrB₂-SiC powders, a novel molten-salt and microwave-modified boro/carbothermal reduction method (MSM-BCTR) was developed to synthesize ZrB₂-SiC powders. As a result, phase pure ZrB₂-SiC powders can be obtained by firing low-cost zircon (ZrSiO₄), amorphous carbon (C), and boron carbide (B₄C) at a reduced temperature of 1200 °C for only 20 min...
September 24, 2018: Materials
Dustin Trail, Patrick Boehnke, Paul S Savage, Ming-Chang Liu, Martha L Miller, Ilya Bindeman
Hydrosphere interactions and alteration of the terrestrial crust likely played a critical role in shaping Earth's surface, and in promoting prebiotic reactions leading to life, before 4.03 Ga (the Hadean Eon). The identity of aqueously altered material strongly depends on lithospheric cycling of abundant and water-soluble elements such as Si and O. However, direct constraints that define the character of Hadean sedimentary material are absent because samples from this earliest eon are limited to detrital zircons (ZrSiO4 )...
October 9, 2018: Proceedings of the National Academy of Sciences of the United States of America
Mami Takehara, Kenji Horie, Tomokazu Hokada, Shoichi Kiyokawa
In this data article, we provide information on the recovery rate and scanning electron microscope (SEM) images of the external morphology of zircon grains separated from two rock samples (AS3 and TEMORA 2) using both mechanical and electrical pulverization systems. The data in this article are related to the research article entitled "New insight into disturbance of U-Pb and trace-element systems in hydrothermally altered zircon via SHRIMP analyses of zircon from the Duluth Gabbro" (Takehara et al...
August 2018: Data in Brief
Jicheng Zhang, Yong Li, Yongshui Huang, Jinwei Jiang, Siu-Chun M Ho
In recent years, the piezoceramic transducer-enabled active sensing technique has been extensively applied to structural damage detection and health monitoring, in civil engineering. Being abundant and renewable, timber has been widely used as a building material in many countries. However, one of the more challenging applications of timber, in construction, is the potential damage caused by moisture. Increased moisture may cause easier warping of timber components and encourage corrosion of integrated metal members, on top of potentially causing rot and decay...
September 14, 2018: Sensors
Donglin Han, Shigeaki Uemura, Chihiro Hiraiwa, Masatoshi Majima, Tetsuya Uda
Y-doped BaZrO3 (BZY) is currently the most promising proton-conductive ceramic-type electrolyte for application in electrochemical devices, including fuel cells and electrolyzer cells. However, owing to its refractory nature, sintering additives, such as NiO, CuO, or ZnO are commonly added to reduce its high sintering temperature from 1600 °C to approximately 1400 °C. Even without deliberately adding a sintering additive, the NiO anode substrate provides another source of the sintering additive; during the co-sintering process, NiO diffuses from the anode into the BZY electrolyte layer...
September 17, 2018: ChemSusChem
Andrea Fildani, Angela M Hessler, Cody C Mason, Matthew P McKay, Daniel F Stockli
Sediment eroded from continents during ice ages can be rapidly (<104 years) transferred via rivers to the deep-sea and preserved in submarine fans, becoming a viable record of landscape evolution. We applied chemical weathering proxies and zircon geo-thermo-chronometry to late Pleistocene sediment recovered from the deep-sea Mississippi fan, revealing interactions between the Laurentide ice sheet (LIS) and broader Mississippi-Missouri catchment between ca. 70,000 and 10,000 years ago (70 to 10 ka). Sediment contribution from the Missouri catchment to the Mississippi fan was low between 70 and 30 ka but roughly doubled after the Last Glacial Maximum (LGM)...
September 14, 2018: Scientific Reports
Nikita N Avdievitch, Todd A Ehlers, Christoph Glotzbach
We present a regional analysis of new low-temperature thermochronometer ages from the Central Andean fore arc to provide insights into the exhumation history of the western Andean margin. To derive exhumation rates over 10 million-year timescales, 38 new apatite and zircon (U-Th)/He ages were analyzed along six ~500-km long near-equal-elevation, coast parallel, transects in the Coastal Cordillera (CC) and higher-elevation Precordillera (PC) of the northern Chilean Andes between latitudes 18.5°S and 22.5°S...
July 2018: Tectonics
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