Bearing Fault Diagnosis Based on Multi-Scale CNN and Bidirectional GRU

This research received no external funding.Peer reviewedPublisher PD

Origin of the high piezoelectric response in PbZr(1-x)TixO3

High resolution x-ray powder diffraction measurements on poled PbZr(1-x)TixO3 (PZT) ceramic samples close to the rhombohedral-tetragonal phase boundary (the so-called morphotropic phase boundary, MPB) have shown that for both rhombohedral and tetragonal compositions, the piezoelectric elongation of the unit cell does not occur along the polar directions but along those directions associated with the monoclinic distortion. This work provides the first direct evidence for the origin of the very high piezoelectricity in PZT.Comment: 4 pages, 4 EPS figures embedded. More specific title and abstract. To appear in Phys. Rev. Let

Geometric reconstruction methods for electron tomography

Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and nonlinear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full $180^\circ$ tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire

Adsorption of chromium VI from aqueous solutions onto nanoparticle sorbent: Chitozan-Fe-Zr

Background and purpose: Various contaminants are released into water resources each year as a results of urbanization and industrialization. Chromium VI is one of the most toxic metals released into the aquatic environments, wastewater, and soil mainly via industrial sewage. The purpose of this study was to evaluate the performance of iron-zirconium/chitosan magnetic nanoparticles composite in removal of hexavalent chromium VI from aquatic environments. Materials and methods: A pilot-study was conducted in laboratory scale. Nancomposites synthesis was done using chemical precipitation and tested by SEM, XRD, and FTIR. Various factors such as contact time (0-720 min), initial pH of the solution (2-12), adsorbent dose (0.4-2 gr), initial concentration of metal (0-10 milligrams per liter), and the system temperature (15-35 �) were studied. The concentration of heavy metal chromium was measured using a spectrophotometer at 540nm. Results: The results showed that the highest removal efficiency of heavy metal chromium was obtained at pH 4.0 (52.99). Moreover, addition of 1 gr composite in the same concentration could boost removing the hexavalent chromium by more than 91. Increasing the concentration levels of heavy metals had little impact on the removal efficiency. Adsorption isotherms fitted the Freundlich isotherm. Conclusion: According to the results, the absorbent showed a high performance in removing chromium VI from aquatic environments. © 2016, Mazandaran University of Medical Sciences. All rights reserved

Heterovalent and A-atom effects in A(B'B'')O3 perovskite alloys

Using first-principles supercell calculations, we have investigated energetic, structural and dielectric properties of three different A(B'B'')O_3 perovskite alloys: Ba(Zn_{1/3}Nb_{2/3})O_3 (BZN), Pb(Zn_{1/3}Nb_{2/3})O_3 (PZN), and Pb(Zr_{1/3}Ti_{2/3})O_3 (PZT). In the homovalent alloy PZT, the energetics are found to be mainly driven by atomic relaxations. In the heterovalent alloys BZN and PZN, however, electrostatic interactions among B' and B'' atoms are found to be very important. These electrostatic interactions are responsible for the stabilization of the observed compositional long-range order in BZN. On the other hand, cell relaxations and the formation of short Pb--O bonds could lead to a destabilization of the same ordered structure in PZN. Finally, comparing the dielectric properties of homovalent and heterovalent alloys, the most dramatic difference arises in connection with the effective charges of the B' atom. We find that the effective charge of Zr in PZT is anomalous, while in BZN and PZN the effective charge of Zn is close to its nominal ionic value.Comment: 7 pages, two-column style with 2 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#lb_he

Nanomagnetic properties of the meteorite cloudy zone.

Meteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the "cloudy zone," a nanoscale intergrowth containing tetrataenite-a naturally occurring hard ferromagnetic mineral that has potential applications as a sustainable alternative to rare-earth permanent magnets. Here we use a combination of high-resolution electron diffraction, electron tomography, atom probe tomography (APT), and micromagnetic simulations to reveal the 3D architecture of the cloudy zone with subnanometer spatial resolution and model the mechanism of remanence acquisition during slow cooling on the meteorite parent body. Isolated islands of tetrataenite are embedded in a matrix of an ordered superstructure. The islands are arranged in clusters of three crystallographic variants, which control how magnetic information is encoded into the nanostructure. The cloudy zone acquires paleomagnetic remanence via a sequence of magnetic domain state transformations (vortex to two domain to single domain), driven by Fe-Ni ordering at 320 °C. Rather than remanence being recorded at different times at different positions throughout the cloudy zone, each subregion of the cloudy zone records a coherent snapshot of the magnetic field that was present at 320 °C. Only the coarse and intermediate regions of the cloudy zone are found to be suitable for paleomagnetic applications. The fine regions, on the other hand, have properties similar to those of rare-earth permanent magnets, providing potential routes to synthetic tetrataenite-based magnetic materials.European Research Counci

Estimation of Inbreeding Coefficients Using Pedigree and Microsatellite Markers and Its Effects on Economic Traits of Shirvan Kordi Sheep

INTRODUCTION Intensive selection within a single population of finite size reduces the genetic variability and increases the rate of inbreeding KEY WORDS Research Article Estimation of Inbreeding Coefficients in Shirvan Kordi Sheep In the overdominance hypothesis, inbreeding depression is attributable to higher fitness of heterozygotes for the loci in question. For the partial recessive hypothesis, negative fitness consequences are due to the fixation of recessive or partially recessive deleterious alleles Microsatellites has been widely used as reliable molecular markers to study the genetic relationship of different populations and for indirect measures of inbreeding. They are codominant, highly polymorphic, highly abundant, heritable, locus specific, and easily analyzed and therefore suitable for studies on population phylogenesis constitution This study was carried out using microsatellite markers because they are powerful tools for tracking alleles through a population and to estimate genetic variability and inbreeding Marker data collected provides information on population structure, relatedness and inbreeding MATERIALS AND METHODS Data Pedigree information from 1989 to 2009 of a flock of Kordi sheep maintained at Shirvan Sheep Breeding Station was used. Pedigree file contained information on individual identification number, sex, type of birth, dam and sire as well as birth date and included 7170 registered animals (3332 males and 3838 females), progeny of177 sires and 2182 dams. Pedigree analysis Inbreeding coefficients of the animals were computed using the CFC program Microsatellite method Blood samples (5 mL) of 100 animals were collected from the jugular vein and transferred into vacutainer tubes containing 0.5 molar EDTA as anticoagulant and frozen at -20 ˚C. Total DNA was isolated from blood samples using the Diatom DNA Kit, according to the manufacturer instructions. The quantity and quality of the isolated DNA was determined using both spectrophotometry and by 0.8% agarose gel electrophoresis. Characteristics of the microsatellite markers used in this study are listed in Approximately, 100 ng DNA (adjusted concentration) was used as template for polymerase chain reaction (PCR). The PCR reaction cycle was carried out in a the rmocycler (Biorad) by denaturation at 95 ˚C for 4 min, denaturation at 95 ˚C for 45 sec, primer annealing for 45 sec at the desired temperature (55-60 ˚C) and an extension for 1 min at 72 ˚C, repeating the cycle 35 times. The final extension step was at 72 ˚C for 4 min. The PCR amplification was conducted in a 12 μL volume. PCR products were analyzed by vertical electrophoresis in 6% non-denaturing polyacrylamide gel (170 V, 3-4 h) and bands visualized by rapid silver staining Molecular data analysis Molecular data were analysed using the POPGENE V1.32 RESULTS AND DISCUSSION Pedigree analysis The analysis of pedigree revealed that mean level of inbreeding (F) of all animals acrossall years (1989-2009) was 0.668%. Moreover, the minimum and maximum coefficientsof inbreeding for the animals in the flock was 0 and 31.25%, respectively. The low average coefficient of inbreeding could be ascribed to breeding strategies at the station for preventing mating of relatives. Totally, 23.26% of the animals (1668 out of 7170) were inbred with a mean inbreeding coefficient of 2.87%. In the pedigree, 3332 and 3838 of the animals were males and females with mean inbreeding coefficients of 0.693% and 0.646%, respectively. Out of all, 1668 animals were inbred. These included 823 males and 845 females having average inbreeding coefficient of 2.81% and 2.93%, respectively. These results indicated that fewmatings of close relatives have occurred. Descriptive statistics for inbreeding coefficients for the entire population and the inbred portion of the population are shown in 135 Estimation of Inbreeding Coefficients in Shirvan Kordi Sheep Mean of all traits decreased and increased irregularly by increasing inbreeding coefficients. This could be due to fewer records in the numerically higher classes of inbreeding. Inbreeding depression Details of the data used for the estimation of inbreeding depression are given in Regression coefficients and their standard errors on inbreeding coefficients were -0.0013 ± 0.0003 kg for BWT, 0.080 ± 0.015 kg for WWT, 0.001 ± 0.0009 kg for BW6M, -0.065 ± 0.055 kg for BW9M, -0.092 ± 0.063 kg for BW12M, 0.008 ± 0.0066kg for Wool and -0.023 ± 0.012 lambs for LS. Pre-weaning growth traits BWT: birth weight trait; WWT: weaning weight trait; BW6M: body weight at 6 months of age trait; BW9W: body weight at 9 months of age trait; BW12M: body weight at 12 months of age trait; Wool: wool produced annually and LS: number of lambs per ewe lambing. Changes for every one percent increase in inbreeding coefficient for BWT and WWT were -0.0131 and 0.0795 kg, respectively. Regression coefficient estimate for BWT Regression coefficients for BW in the 9 th and 12 th month were more than all the other studied traits. Estimates of -0.0653 and -0.0921 kg per 1% increase in inbreeding coefficient for BW in 9 th month and BW in 12 th month, were more than the values reported in other studies. Annual wool production and number of lambs per ewe lambing The effect of inbreeding on wool produced annually and the number of lambs per ewe lambing amounted to 0.0083 kg and -0.023 lambs, respectively. For the annual wool production, the linear effect of individual inbreeding, regression was positive but non-significant. On the average, an increase in 1 percent in individual inbreeding increased the wool produced annually by 0.0083 kg. A review b

Stability of the monoclinic phase in the ferroelectric perovskite PbZr(1-x)TixO3

Recent structural studies of ferroelectric PbZr(1-x)TixO3 (PZT) with x= 0.48, have revealed a new monoclinic phase in the vicinity of the morphotropic phase boundary (MPB), previously regarded as the the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper, the stability region of all three phases has been established from high resolution synchrotron x-ray powder diffraction measurements on a series of highly homogeneous samples with 0.42 <=x<= 0.52. At 20K the monoclinic phase is stable in the range 0.46 <=x<= 0.51, and this range narrows as the temperature is increased. A first-order phase transition from tetragonal to rhombohedral symmetry is observed only for x= 0.45. The MPB, therefore, corresponds not to the tetragonal-rhombohedral phase boundary, but instead to the boundary between the tetragonal and monoclinic phases for 0.46 <=x<= 0.51. This result provides important insight into the close relationship between the monoclinic phase and the striking piezoelectric properties of PZT; in particular, investigations of poled samples have shown that the monoclinic distortion is the origin of the unusually high piezoelectric response of PZT.Comment: REVTeX file, 7 figures embedde

Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3)

We report first principles density functional studies using plane wave basis sets and pseudopotentials and all electron linear augmented plane wave (LAPW) of the relative stability of various ferroelectric and antiferroelectric supercells of PMN for 1:2 chemical ordering along [111] and [001]. We used linear response with density functional perturbation theory (DFPT) as implemented in the code ABINIT to compute the Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies and LO-TO splittings. The polar response is different for supercells ordered along [111] and [001]. Several polar phonon modes show significant coupling with the macroscopic electric field giving giant LO-TO splittings. For [111] ordering, a polar transverse optic (TO) mode with E symmetry is found to be unstable in the ferroelectric P3m1 structure and the ground state is found to be triclinic. Multiple phonon instabilities of polar modes and their mode couplings provide the pathway for polarization rotation. The Born effective charges in PMN are highly anisotropic and this anisotropy contributes to the observed huge electromechanical coupling in PMN solid solutions.Comment: 34 pages, 6 figures. to appear in PR