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Claudio D'Amico, Giovanni Bianchi, Elisa Padovano, Sara Biamino, Alberta Aversa, Claudio Badini, Alberto Ortona
BACKGROUND: Silicon carbide ceramics obtained by reactive infiltration of silicon (SRI) have many industrial applications especially involving severe and high temperature conditions. In this study, the oxidation behavior in air of Si-SiC-ZrB2 systems at a high temperature (1500°C) for dwelling times of up to 48 hours was examined. METHODS: The oxidation process was analyzed on the basis of elemental maps and X-ray diffraction patterns taken, respectively, on the core and on the surface of the specimens, together with weight gains and the average thicknesses of the resulting scale...
October 6, 2017: Journal of Applied Biomaterials & Functional Materials
Kazushige Ueda, Yuhei Shimizu, Kouta Nagamizu, Masashi Matsuo, Tetsuo Honma
The difference in Tb(3+) green luminescence intensities in doped perovskite(ABO3)-type alkaline earth stannates, AeSnO3 (Ae = Ca, Sr, Ba), and the Mg codoping effect on the luminescence intensities in doped CaMO3 (M = Sn, Zr) were investigated utilizing the X-ray absorption fine structures (XAFS) of the Tb LIII absorption edge. It is considered that the local symmetry at A sites is responsible for the different Tb(3+) luminescence intensities in AeSnO3 (Ae = Ca, Sr, Ba) doped with Tb ions at A sites. However, it was found from the XAFS spectra that some Tb ions are unintentionally stabilized at B sites as Tb(4+), especially in BaSnO3...
October 3, 2017: Inorganic Chemistry
Deng-Fa He, Di Li, Chuan-Xin Li, Ying-Qiang Li, Qing-Hua Mei
Well W117 in the Sichuan Basin reveals a suite of ~814 Ma quartz monzonites, unconformably overlain by Sinian clastic and carbonate sediments. The quartz monzonites contain no muscovite and amphibole, and are characterized by high SiO2 (72.26-77.93%), total alkali, and TFe2O3/MgO content, and low P2O5 and CaO abundance, with variable A/CNK ratio (0.93-1.19), classified as metaluminous to weakly aluminous highly fractionated I-type granites. They are preserved in the Neoproterozoic rift and exhibit restricted negative εNd(t) values (-7...
October 2, 2017: Scientific Reports
Hisatoshi Ito, Christopher J Spencer, Martin Danišík, Carl W Hoiland
Plutons are formed by protracted crystallization of magma bodies several kilometers deep within the crust. The temporal frequency (i.e. episodicity or 'tempo') of pluton formation is often poorly constrained as timescales of pluton formation are largely variable and may be difficult to resolve by traditional dating methods. The Hida Mountain Range of central Japan hosts the youngest exposed plutons on Earth and provides a unique opportunity to assess the temporal and spatial characteristics of pluton emplacement at high temporal resolution...
September 29, 2017: Scientific Reports
Tianyong Jiang, Junbo Zheng, Linsheng Huo, Gangbing Song
With the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. To ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. However, it is still a challenge to monitor the grouting quality of post-tensioning tendon ducts, due to the invisibility of the grouting. The authors' previous work proposed a real-time method that employed a stress wave-based active sensing approach with piezoceramic transducers to monitor the grouting compactness of a Post-Tensioning Tendon Duct (PTTD)...
September 29, 2017: Sensors
Long Xu, Jingwen Zhang, Hua Zhao, Haibin Sun, Caixia Xu
Quasi-period cylindrical nanostructures with both diameters and intervals of about 100 nm are manufactured on the surfaces of Nd(3+)-doped lanthanum lead zirconate titanate ceramics by femtosecond laser irradiation under SF6 atmosphere. A light-emission enhancement of more than 20 times is investigated, accompanied by an extremely long trailing-off time of light emission and lower threshold. A specific polarization state of the light emission is achieved and tuned by changing the incident regions of the pumping source...
September 1, 2017: Optics Letters
Marco Schleutker, Jochen Bahner, Chih-Long Tsai, Detlef Stolten, Carsten Korte
The Li(+) ion transfer between a solid and a liquid Li(+) electrolyte has been investigated by DC polarisation techniques. The current density i is measured as a function of the electrochemical potential drop Δ[small mu, Greek, tilde]Li(+) at the interface, using a liquid electrolyte with different Li(+) concentrations. The subject of this experimental study is the interface between the solid electrolyte Ta-substituted lithium lanthanum zirconate (Li6.6La3Zr1.6Ta0.4O12) and a liquid electrolyte consisting of LiPF6 dissolved in ethylene carbonate/dimethyl carbonate (1 : 1)...
October 11, 2017: Physical Chemistry Chemical Physics: PCCP
Nikolaos Galanakis, Karl P Travis
We present a new method of characterizing damage arising from α-recoil cascades in amorphous materials including glasses. The approach taken is topological, yielding information on atom connectivity and utilizing complete sets of orthogonal functions (spherical harmonics and Hermite functions) to compute order parameters. The utility of our new approach is demonstrated by first applying it to models of radiation-damaged crystalline zircon, enabling validation against the standard defect counting method (Wigner-Seitz)...
October 2, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Aleksander Matavž, Vid Bobnar, Barbara Malic
The surface properties of a substrate are among the most important parameters in the printing technology of functional materials, determining not only the printing resolution but also the stability of the printed features. This paper addresses the wetting difficulties encountered during inkjet printing on homogeneous substrates as a result of improper surface properties. We show that the wetting of a substrate and, consequently, the quality of the printed pattern, can be mediated through the deposition of polymeric layers that are a few nanometers thick...
September 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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
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
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
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
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
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
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
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
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
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
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
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