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https://www.readbyqxmd.com/read/28811021/quantitative-analysis-of-major-and-trace-elements-in-nh4hf2-modified-silicate-rock-powders-by-laser-ablation-inductively-coupled-plasma-mass-spectrometry
#1
Wen Zhang, Zhaochu Hu, Yongsheng Liu, Wenwu Yang, Haihong Chen, Shenghong Hu, Hongyan Xiao
In this paper, we described a NH4HF2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH4HF2 at 230 °C for 3 h form ultrafine powders with a typical grain size d80 < 8.5 μm, and various silicate rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder...
August 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28798407/exhumation-history-of-the-sanshandao-au-deposit-jiaodong-constraints-from-structural-analysis-and-u-th-he-thermochronology
#2
Xuan Liu, Hong-Rui Fan, Noreen J Evans, Kui-Feng Yang, Martin Danišík, Brent I A McInnes, Ke-Zhang Qin, Xue-Feng Yu
The Sanshandao gold deposit contains an estimated Au resource of >1500 tons, however little is known about the history of exhumation, and the magnitude of displacement on the ore-hosting fault. Structural measurement revealed two phases of normal and one phase of sinistral movement on the fault. Despite of intra-sample dispersions, (U-Th)/He ages from two sub-vertical profiles show decreasing trends from the surface down to -3560 m (zircon: 123 Ma to 55 Ma; apatite 103 Ma to 0.3 Ma). Over-dispersion of AHe ages likely reflects the presence of undetected inclusions...
August 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28777394/in-vitro-evaluation-of-onlay-restorations-on-primary-teeth
#3
Kadriye G U Güzel, Ayşe C Altun, Zuhal Kırzıoğlu
PURPOSE: Many novel materials have been developed such as composite resin, ceramic, zircon or metal-supported ceramic for use in aesthetic restoration of primary teeth and permanent teeth with extensive crown damage. The aim of the present study was to compare microtensile bond strengths on materials using the microtensile bond strength test. MATERIALS AND METHODS: The microtensile bond strength on the primary tooth dentin was measured on extracted primary teeth using an indirect method and fracture patterns were evaluated...
August 2, 2017: International Journal of Artificial Organs
https://www.readbyqxmd.com/read/28774067/the-effect-of-acceptor-and-donor-doping-on-oxygen-vacancy-concentrations-in-lead-zirconate-titanate-pzt
#4
Christoph Slouka, Theresa Kainz, Edvinas Navickas, Gregor Walch, Herbert Hutter, Klaus Reichmann, Jürgen Fleig
The different properties of acceptor-doped (hard) and donor-doped (soft) lead zirconate titanate (PZT) ceramics are often attributed to different amounts of oxygen vacancies introduced by the dopant. Acceptor doping is believed to cause high oxygen vacancy concentrations, while donors are expected to strongly suppress their amount. In this study, La(3+) donor-doped, Fe(3+) acceptor-doped and La(3+)/Fe(3+)-co-doped PZT samples were investigated by oxygen tracer exchange and electrochemical impedance spectroscopy in order to analyse the effect of doping on oxygen vacancy concentrations...
November 22, 2016: Materials
https://www.readbyqxmd.com/read/28773096/piezoelectric-ceramics-of-the-1-x-bi0-50na0-50tio%C3%A2-xba0-90ca0-10tio%C3%A2-lead-free-solid-solution-chemical-shift-of-the-morphotropic-phase-boundary-a-case-study-for-x-0-06
#5
Rodrigo Vivar-Ocampo, Lorena Pardo, David Ávila, Emilio Morán, Amador M González, Lauro Bucio, María-Elena Villafuerte-Castrejón
Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate-titanate for actuators is that of Bi0.50Na0.50TiO₃ (BNT) based solid solutions. The pseudo-binary (1 - x)Bi0.50Na0.50TiO₃-xBa1 - yCayTiO₃ system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0...
July 1, 2017: Materials
https://www.readbyqxmd.com/read/28772408/ferroelectric-domain-structure-and-local-piezoelectric-properties-of-lead-free-ka0-5na0-5-nbo%C3%A2-and-bifeo%C3%A2-based-piezoelectric-ceramics
#6
REVIEW
Denis Alikin, Anton Turygin, Andrei Kholkin, Vladimir Shur
Recent advances in the development of novel methods for the local characterization of ferroelectric domains open up new opportunities not only to image, but also to control and to create desired domain configurations (domain engineering). The morphotropic and polymorphic phase boundaries that are frequently used to increase the electromechanical and dielectric performance of ferroelectric ceramics have a tremendous effect on the domain structure, which can serve as a signature of complex polarization states and link local and macroscopic piezoelectric and dielectric responses...
January 7, 2017: Materials
https://www.readbyqxmd.com/read/28763288/particle-size-distribution-a-key-factor-in-estimating-powder-dustiness
#7
Ana López-Lilao, Forner Vicenta Sanfélix, Gasch Gustavo Mallol, Gimeno Eliseo Monfort
ASTRACT A wide variety of raw materials, involving more than twenty samples of quartzes, feldspars, nephelines, carbonates, dolomites, sands, zircons, and alumina, were selected and characterised. Dustiness, i.e. a materials' tendency to generate dust on handling, was determined using the continuous drop method. These raw materials were selected to encompass a wide range of particle sizes (1.6-294 µm) and true densities (2650-4680 kg/m(3)). The dustiness of the raw materials, i.e. their tendency to generate dust on handling, was determined using the continuous drop method...
August 1, 2017: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/28754976/constraining-shifts-in-north-atlantic-plate-motions-during-the-palaeocene-by-u-pb-dating-of-svalbard-tephra-layers
#8
Morgan T Jones, Lars E Augland, Grace E Shephard, Seth D Burgess, Gauti T Eliassen, Malte M Jochmann, Bjarki Friis, Dougal A Jerram, Sverre Planke, Henrik H Svensen
Radioisotopic dating of volcanic minerals is a powerful method for establishing absolute time constraints in sedimentary basins, which improves our understanding of the chronostratigraphy and evolution of basin processes. The relative plate motions of Greenland, North America, and Eurasia changed several times during the Palaeogene. However, the timing of a key part of this sequence, namely the initiation of compression between Greenland and Svalbard, is currently poorly constrained. The formation of the Central Basin in Spitsbergen is inherently linked to changes in regional plate motions, so an improved chronostratigraphy of the sedimentary sequence is warranted...
July 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28738251/quantification-of-some-elements-of-nuclear-and-industrial-interest-from-zircon-mineral-using-neutron-activation-analysis-and-passive-gamma-ray-spectroscopy
#9
M F Attallah, M A Hilal, S I Moussa
A combined of various nuclear and analytical techniques were used for characterization of Egyptian zircon ore. Neutron activation analysis has been used for determination of the major, minor and trace elements from zircon ore. Non-destructive gamma-ray technique is also used for the radiometric analysis of zircon ore to quantify the natural radionuclides such as (238)U, (235)U, (232)Th, (226)Ra and (40)K. Zircon ore has been characterized by different analytical tools such as Fourier transformer infrared (FTIR), X-ray fluorescence (XRF), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM)...
July 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28729807/observation-of-crack-growth-in-a-polycrystalline-ferroelectric-by-synchrotron-x-ray-diffraction
#10
J E Huber, F Hofmann, S Barhli, T J Marrow, C Hildersley
Pre-cracked samples of unpoled, polycrystalline, soft ferroelectric lead zirconate titanate were subjected to electrical and mechanical loading whilst using synchrotron X-ray diffraction to map strain-fields. Clear evidence is found of switching around the crack tip and development of a crack-wake. A J-integral estimate based on strain-field data provided a sensitive measure of strain changes during loading. Electrical loading did not cause crack advance or crack-tip switching; this provides evidence for electrically permeable crack models...
November 2017: Scripta Materialia
https://www.readbyqxmd.com/read/28708541/total-ionizing-dose-effects-on-piezoelectric-thin-film-cantilevers-with-oxide-electrodes
#11
Ryan Q Rudy, Kyle M Grove, Manuel Rivas, Jonathon Guerrier, Cory Cress, Robert R Benoit, Jacob L Jones, Evan Glaser, Steven Brewer, Nazanin Bassiri-Gharb, Ronald G Polcawich
This paper reports on the ionizing radiation effects in lead-zirconate-titanate (PZT) with varied top electrode material and bias condition during radiation. A technique to characterize the piezoelectric performance of films unclamped from the substrate is described, and used to demonstrate the effects of radiation on the material's electromechanical behavior. Both platinum and iridium oxide top electrodes were examined, and iridium oxide appears to significantly mitigate radiation-induced damage that is observed in platinum top electrode samples...
July 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28691580/characterization-of-solid-airborne-particles-deposited-in-snow-in-the-vicinity-of-urban-fossil-fuel-thermal-power-plant-western-siberia
#12
Anna Talovskaya, Egor Yazikov, Ekaterina Filimonenko, Jean-Christophe Lata, Junbeum Kim, Tatyana Shakhova
Recognition and detailed characterization of solid particles emitted from thermal power plants in the environment is highly important due to their potential detrimental effects on human health. Snow cover is often used for the identification of the presence of anthropogenic emissions in the environment. However, little is known about types, physical and chemical properties of solid airborne particles (SAP) deposited in snow around thermal power plants. The purpose of this study is to quantify and characterize in detail the traceable SAP deposited in snow in the vicinity of fossil fuel thermal power plant in order to identify their emissions into the environment...
July 10, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28658320/a-u-pb-zircon-age-constraint-on-the-oldest-recorded-air-breathing-land-animal
#13
Stephanie E Suarez, Michael E Brookfield, Elizabeth J Catlos, Daniel F Stöckli
The oldest-known air-breathing land animal is the millipede Pneumodesmus newmani, found in the Cowie Harbour Fish Bed at Stonehaven, Scotland. Here we report the youngest, most concordant 238U-206Pb zircon age from ash below the fish bed of 413.7±4.4 Ma (±2σ), whereas the youngest age from a tuffaceous sandstone above the fish bed is statistically indistinguishable at 414.3±7.1 Ma. The Cowie Harbour Fish Bed thus appears to be lowermost Devonian (Lochkovian), contrary to the previously accepted mid-Silurian age based on palynomorphs from adjacent exposures...
2017: PloS One
https://www.readbyqxmd.com/read/28642551/aesthetic-preformed-crowns-for-primary-teeth
#14
Greig D Taylor
Data sourcesMedline, Cochrane central register of controlled trials, US National Institutes of Health Trials Register and the World Health Organization International Clinical Trials Registry Platform.Study selectionEnglish language randomised clinical trials comparing APCs with conventional restorative techniques for primary teeth.Data extraction and synthesisStudy selection and data abstraction were conducted independently by two reviewers. Risk of bias was assessed using the Cochrane risk of bias tool. Study characteristics and results were described qualitatively...
June 23, 2017: Evidence-based Dentistry
https://www.readbyqxmd.com/read/28635034/modular-transmit-receive-arrays-using-very-high-permittivity-dielectric-resonator-antennas
#15
Thomas P A O'Reilly, Thomas Ruytenberg, Andrew G Webb
PURPOSE: Dielectric resonator antenna (DRAs) are compact structures that exhibit low coupling between adjacent elements and therefore can be used as MRI transmit arrays. In this study, we use very high permittivity materials to construct modular flexible transceive arrays of a variable numbers of elements for operation at 7T. METHODS: DRAs were constructed using rectangular blocks of ceramic (lead zirconate titanate, εr  = 1070) with the transverse electric (TE)01 mode tuned to 298 MHz...
June 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28619940/rapid-cooling-and-cold-storage-in-a-silicic-magma-reservoir-recorded-in-individual-crystals
#16
Allison E Rubin, Kari M Cooper, Christy B Till, Adam J R Kent, Fidel Costa, Maitrayee Bose, Darren Gravley, Chad Deering, Jim Cole
Silicic volcanic eruptions pose considerable hazards, yet the processes leading to these eruptions remain poorly known. A missing link is knowledge of the thermal history of magma feeding such eruptions, which largely controls crystallinity and therefore eruptability. We have determined the thermal history of individual zircon crystals from an eruption of the Taupo Volcanic Zone, New Zealand. Results show that although zircons resided in the magmatic system for 10(3) to 10(5) years, they experienced temperatures >650° to 750°C for only years to centuries...
June 16, 2017: Science
https://www.readbyqxmd.com/read/28598143/composite-polymer-electrolytes-with-li7la3zr2o12-garnet-type-nanowires-as-ceramic-fillers-mechanism-of-conductivity-enhancement-and-role-of-doping-and-morphology
#17
Ting Yang, Jin Zheng, Qian Cheng, Yan-Yan Hu, Candace K Chan
Composite polymer solid electrolytes (CPEs) containing ceramic fillers embedded inside a polymer-salt matrix show great improvements in Li(+) ionic conductivity compared to the polymer electrolyte alone. Lithium lanthanum zirconate (Li7La3Zr2O12, LLZO) with a garnet-type crystal structure is a promising solid Li(+) conductor. We show that by incorporating only 5 wt % of the ceramic filler comprising undoped, cubic-phase LLZO nanowires prepared by electrospinning, the room temperature ionic conductivity of a polyacrylonitrile-LiClO4-based composite is increased 3 orders of magnitude to 1...
June 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28593944/non-ising-and-chiral-ferroelectric-domain-walls-revealed-by-nonlinear-optical-microscopy
#18
Salia Cherifi-Hertel, Hervé Bulou, Riccardo Hertel, Grégory Taupier, Kokou Dodzi Honorat Dorkenoo, Christian Andreas, Jill Guyonnet, Iaroslav Gaponenko, Katia Gallo, Patrycja Paruch
The properties of ferroelectric domain walls can significantly differ from those of their parent material. Elucidating their internal structure is essential for the design of advanced devices exploiting nanoscale ferroicity and such localized functional properties. Here, we probe the internal structure of 180° ferroelectric domain walls in lead zirconate titanate (PZT) thin films and lithium tantalate bulk crystals by means of second-harmonic generation microscopy. In both systems, we detect a pronounced second-harmonic signal at the walls...
June 8, 2017: Nature Communications
https://www.readbyqxmd.com/read/28580142/enhanced-pyroelectric-and-piezoelectric-properties-of-pzt-with-aligned-porosity-for-energy-harvesting-applications
#19
Yan Zhang, Mengying Xie, James Roscow, Yinxiang Bao, Kechao Zhou, Dou Zhang, Chris R Bowen
This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction...
April 14, 2017: Journal of Materials Chemistry. A, Materials for Energy and Sustainability
https://www.readbyqxmd.com/read/28543615/improved-image-quality-and-reduced-power-deposition-in-the-spine-at-3-t-using-extremely-high-permittivity-materials
#20
Kirsten Koolstra, Peter Börnert, Wyger Brink, Andrew Webb
PURPOSE: To explore the effect of using extremely high permittivity (εr ∼1,000) materials on image quality and power requirements of spine imaging at 3 T. THEORY AND METHODS: A linear array of high permittivity dielectric blocks made of lead zirconate titanate (PZT) was designed and characterized by electromagnetic simulations and experiments. Their effect on the transmit efficiency, receive sensitivity, power deposition, and diagnostic image quality was analyzed in vivo in 10 healthy volunteers...
May 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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