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Sample records for respects zr behaves

  1. Why consumers behave as they do with respect to food safety and risk information

    Verbeke, Wim; Frewer, Lynn J.; Scholderer, Joachim

    2007-01-01

    rankings. The aim of this contribution is to provide a better understanding to food risk analysts of why consumers behave as they do with respect to food safety and risk information. This paper presents some cases of seemingly irrational and inconsistent consumer behaviour with respect to food safety...... and risk information and provides explanations for these behaviours based on the nature of the risk and individual psychological processes. Potential solutions for rebuilding consumer confidence in food safety and bridging between lay and expert opinions towards food risks are reviewed. These include......In recent years, it seems that consumers are generally uncertain about the safety and quality of their food and their risk perception differs substantially from that of experts. Hormone and veterinary drug residues in meat persist to occupy a high position in European consumers' food concern...

  2. Hospital doctors behave differently, and only by respecting the fundamentals of professional organizations will managers be able to create common goals with professionals.

    Van Dijck, H

    2014-08-01

    Hospital doctors behave differently from other hospital workers. The general and specific characteristics of the doctors' behavior are described. As professionals, doctors want to make autonomous decisions and more specifically, they negotiate differently. The best description of their negotiation style is one that features multi-actor, multi-issue characteristics. They behave as actors in a network in never-ending rounds of negotiations with variable issues up for discussion: one time you lose, the next you win. A doctor's career starts with a long residency period in which he or she absorbs professional habits. His or her knowledge and way of organizing are implicit. It is hard for him or her to explicitly describe what he or she is doing. This makes it difficult for managers to discuss quality issues with doctors. Dealing with disruptive behavior is not easy either. The difficult tasks of the chief medical officer, who acts as a go-between, are highlighted. Only when managers respect the fundamentals of the professional organization will they be able to create common goals with the professionals. Common goals bring about better care in hospitals.

  3. RESPECT

    Teyeb, Oumer; Boussif, Malek; Sørensen, Troels Bundgaard

    2005-01-01

    the performance from an end-2-end (E2E), user-perceived Quality Of Service (QoS) point of view. In this paper, the design and implementation of RESPECT, an easily configurable network emulator is described. RESPECT was originally geared towards Universal Mobile Communications System (UMTS) networks, but thanks...... to its modular and scalable design, it is being extended for generic heterogeneous networks. Using RESPECT, QoS studies can be carried out to study the behavior of different services in different network conditions, identify generalized service dependent performance metrics for already existing services...

  4. Two Different Macaviruses, ovine herpesvirus-2 and caprine herpesvirus-2, behave differently in water buffaloes than in cattle or in their respective reservoir species.

    Anina B J Stahel

    Full Text Available The ongoing global spread of "exotic" farm animals, such as water buffaloes, which carry their native sets of viruses, may bear unknown risks for the animals, into whose ecological niches the former are introduced and vice versa. Here, we report on the occurrence of malignant catarrhal fever (MCF on Swiss farms, where "exotic" water buffaloes were kept together with "native" animals, i.e. cattle, sheep, and goats. In the first farm with 56 water buffaloes, eight cases of MCF due to ovine herpesvirus-2 (OvHV-2 were noted, whereas additional ten water buffaloes were subclinically infected with either OvHV-2 or caprine herpesvirus-2 (CpHV-2. On the second farm, 13 water buffaloes were infected with CpHV-2 and two of those succumbed to MCF. In neither farm, any of the two viruses were detected in cattle, but the Macaviruses were present at high prevalence among their original host species, sheep and goats, respectively. On the third farm, sheep were kept well separated from water buffaloes and OvHV-2 was not transmitted to the buffaloes, despite of high prevalence of the virus among the sheep. Macavirus DNA was frequently detected in the nasal secretions of virus-positive animals and in one instance OvHV-2 was transmitted vertically to an unborn water buffalo calf. Thus, water buffaloes seem to be more susceptible than cattle to infection with either Macavirus; however, MCF did not develop as frequently. Therefore, water buffaloes seem to represent an interesting intermediate-type host for Macaviruses. Consequently, water buffaloes in their native, tropic environments may be vulnerable and endangered to viruses that originate from seemingly healthy, imported sheep and goats.

  5. Shell evolution of stable N = 50-56 Zr and Mo nuclei with respect to low-lying octupole excitations

    Gregor, E.T.; Scheck, M.; Chapman, R.; Gaffney, L.P.; Keatings, J.; Mashtakov, K.R.; O' Donnell, D.; Smith, J.F.; Spagnoletti, P.; Wiseman, C. [University of the West of Scotland, School of Engineering and Computing, Paisley (United Kingdom); SUPA, Scottish Universities Physics Alliance, Glasgow (United Kingdom); Thuerauf, M.; Werner, V. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany)

    2017-03-15

    For the N = 50-56 zirconium (Z = 40) and molybdenum (Z = 42) isotopes, the evolution of subshells is evaluated by extracting the effective single-particle energies from available particle-transfer data. The extracted systematic evolution of neutron subshells and the systematics of the excitation energy of the octupole phonons provide evidence for type-II shape coexistence in the Zr isotopes. Employing a simplistic approach, the relative effective single-particle energies are used to estimate whether the formation of low-lying octupole-isovector excitations is possible at the proposed energies. The results raise doubts about this assignment. (orig.)

  6. How are we behaving?

    2012-01-01

    It’s almost two years since CERN introduced a Code of Conduct. The results may not be immediately measurable, but I’d like to think it’s made the lab a better place to be. The Code of Conduct is based on values that most of us immediately identify with, and so implementing it comes as second nature. Nevertheless, in an organisation of over 10,000 people, it’s useful to have a set of guidelines and there have been occasions on which it’s been necessary to remind people of them.   I use the figure of 10,000 advisedly since the Code of Conduct applies to us all, those on the CERN payroll as well as users of the lab’s facilities and people working for CERN contractors, as long as they are acting on CERN’s behalf. The Code also applies to us whether we are on the CERN site or anywhere else. CERN is a major presence in the region. The way we behave can have a significant influence on how our neighbours perceive us, and how the la...

  7. Diffusion and chemical activity of Zr-Sn and Zr-Ti systems

    Zee, R.H.; Watters, J.F.; Davidson, R.D.

    1986-01-01

    A modified evaporation method was used to determine the diffusion coefficients and the emission rates of Sn and Ti in Zr-Sn and Zr-Ti, respectively, at temperatures between 1605 and 1970 K. Results show that both Sn and Ti diffuse in their respective alloys via a vacancy mechanism. Comparison with data in the literature reveals that the activation energy for diffusion of Sn in Zr-Sn, with Sn content between 3 and 5 at.X is relatively constant from 1200 to 1970 K. From the measured emission rates, values of 103 and 98 kcal/mol were obtained for the enthalpies of sublimation for Sn and Ti in their alloys. With a comparison of the solute vapor pressures with those of the pure elements, partial molar free energies, entropies, and enthalpies for the two systems were determined in the temperature range investigated. The Zr-Sn system shows a very large negative heat of formation (-33 kcal/mol) whereas the Zr-Ti system behaves quite ideally, in agreement with phase-diagram predictions

  8. behaved particle swarm optimization (QPSO)

    Administrator

    2011-06-13

    Jun 13, 2011 ... experiment results of L-glutamic acid fermentation process showed that our ... Key words: Soft-sensing model, quantum-behaved particle swarm optimization ... information about such biochemical variables is, in most practical ...

  9. In situ synthesis and formation mechanism of ZrC and ZrB2 by combustion synthesis from the Co-Zr-B4C system

    Mengxian Zhang

    2015-09-01

    Full Text Available ZrC-ZrB2-based composites were prepared by combustion synthesis (CS reaction from 10 wt.% to 50 wt.% Co-Zr-B4C powder mixtures. With increasing Co contents, the particle sizes of near-spherical ZrC and platelet-like ZrB2 decreased from 1 μm to 0.5 μm and from 5 μm to 2 μm, respectively. In addition, the formation mechanism of ZrC and ZrB2 was explored by the phase transition and microstructure evolution on the combustion wave quenched sample in combination with differential scanning calorimeter analysis. The results showed that the production of ZrC was ascribed to the solid-solid reaction between Zr and C and the precipitation from the Co-Zr-B-C melt, while ZrB2 was prepared from the saturated liquid. The low B concentration in the Co-Zr-B-C liquid and high cooling rate during the CS process led to the presence of Co2B and ZrCo3B2 in the composites. The addition of Co in the Co-Zr-B4C system not only prevented ZrC and ZrB2 particulates from growing, but also promoted the occurrence of ZrC-ZrB2-forming reaction.

  10. Changes in Sensory Responsiveness in Behaving Primates.

    1986-07-14

    controlled behavioral training and monitoring, and electrophysiological recording in awake , behaving monkeys. All I, research equipment listed in the original...recording from the sensorimotor cortices was conducted on May 21. Under general anesthesia, a craniotomy was performed over the pre- and postcentral cortices...Department of Neurosurgery at U.T. Dr. Klein is somewhat unusual in that he has had previous experience recording from awake , behaving monkeys. The experience

  11. Neutron separation energies of Zr isotopes

    Gomes, L.C.; Dietzsch, O.

    1976-01-01

    Q values are reported for (d,t) reactions on all the stable isotopes of zirconium. The neutron separation energies of 94 Zr and 96 Zr differ greatly (by 27.5 and 22.1 keV, respectively) from the values in the 1971 Atomic Mass Evaluation. These results combined with those from other authors seem to indicate that the 1971 values for the masses of 93 Zr and 95 Zr are in error. (orig.) [de

  12. Thermodynamic modeling of the Pt-Zr system

    Gao Yongliang; Guo Cuiping; Li Changrong; Du Zhenmin

    2010-01-01

    By means of the CALPHAD (CALculation of PHAse Diagram) technique, the Pt-Zr system was critically assessed. The solution phases (liquid, bcc, fcc and hcp) are described with the substitutional model. The intermetallic compounds Pt 4 Zr, Pt 4 Zr 3 , αPtZr and Pt 3 Zr 5 are treated as the formula (Pt,Zr) m (Pt,Zr) n by a two-sublattice model with the elements Pt and Zr on the first and the second sublattices, respectively. A two-sublattice model (Pt,Zr) 0.5 (Pt,Zr) 0.5 is applied to describe the compound βPtZr with CsCl-type structure (B2) in order to cope with the order-disorder transition between bcc solution (A2) and βPtZr (B2). Another two-sublattice model (Pt,Zr) 0.75 (Pt,Zr) 0.25 with Ni 3 Ti-type structure (D0 24 ) is applied to describe the compound Pt 3 Zr in order to cope with the order-disorder transition between hexagonal close-packed (A3) and Pt 3 Zr (D0 24 ). The compound Pt 10 Zr 7 is treated as a stoichiometric compound. A set of self-consistent thermodynamic parameters of the Pt-Zr system was obtained. (orig.)

  13. Determination of Nb and Zr in U-Nb-Zr alloys by ICP-AES

    Wang Cuiping; Dong Shizhe; Li Lin; He Meiying

    2003-01-01

    The U-Nb-Zr alloy sample is dissolved by HNO 3 , H 2 O 2 and HF, and the contents of Nb and Zr in the sample are determined on the JY-70 II type ICP-AES by using the internal standard synchronous dilution method. The range of determination is 1%-10% and 0.33%-3.33%, respectively for Nb and Zr. The relative standard deviation is better than 3.2% for Nb, and 2.5% for Zr. The method is rapid and convenient for determining Nb and Zr in U-Nb-Zr alloy sample

  14. Responsiveness in Behaving Monkeys and Human Subjects

    1993-07-31

    Status of Current Research - Statement of Work Each study involving awake , behaving monkey neurophysiological recording used a behavioral paradigm that...anesthesia. A craniotomy was performed at approximately A+ 14.5mm. The recording chamber then was fixed to the skull at a lateral angle of 8’ from

  15. Why consumers behave as they do with respect to food safety and risk information

    Verbeke, W.; Frewer, L.J.; Scholderer, J.; Brabander, de H.F.

    2007-01-01

    In recent years, it seems that consumers are generally uncertain about the safety and quality of their food and their risk perception differs substantially from that of experts. Hormone and veterinary drug residues in meat persist to occupy a high position in European consumers¿ food concern

  16. Comparative study of the core level photoemission of the ZrB{sub 2} and ZrB{sub 12}

    Huerta, L. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Duran, A. [Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autonoma de Mexico, Apartado Postal 2681, Ensenada, Baja California 22800 (Mexico); Falconi, R. [Division Academica de Ciencias Basicas, Universidad Juarez Autonoma de Tabasco, Cunduacan, Tabasco, CP 86690, AP 24 (Mexico); Flores, M. [Departamento de Ingenieria de Proyectos, CUCEI, Universidad de Guadalajara, AP 307, Zapopan Jal 45101 (Mexico); Escamilla, R., E-mail: rauleg@servidor.unam.m [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico)

    2010-05-01

    X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) were used to investigate the binding energies and valence band for ZrB{sub 2} and ZrB{sub 12}. The Zr 3d and B 1s core levels were identified. The Zr 3d core level shows a spin-orbit split 3d{sub 5/2} and 3d{sub 3/2} while that for B 1s core level exhibited a single symmetric peak, these being typical of zirconium and boride signals. Comparing the Zr 3d and B 1s core levels with metallic Zr, B{sub 2}O{sub 3} and ZrO{sub 2} reference materials only a negative chemical shift for Zr 3d associated to ZrB{sub 2} was observed, which suggests that the charge transfer model based on the concept of electronegativity was not applicable to explain the superconductivity in the ZrB{sub 12} sample. The measured valence band using UPS is consistent with the band-structure calculations indicating a higher density of states (DOS) at E{sub F} for ZrB{sub 12} respect to ZrB{sub 2}. Finally, we found that the weak mixed B-p and Zr-d states for ZrB{sub 12} is crucial for the superconductivity due to the state population increased the DOS at the E{sub F}.

  17. Zr-92(d,p)Zr-93 and Zr-92(d,t)Zr-91

    Baron, N.; Fink, C. L.; Christensen, P. R.; Nickels, J.; Torsteinsen, T.

    1972-01-01

    The structures of Zr-93 and Zr-91 were studied by the stripping reaction Zr-92(d,p)Zr-93 and the pick-up reaction Zr-92(d,t)Zr-91 using 13 MeV incident deuterons. The reaction product particles were detected by counter telescope. Typical spectra from the reactions were analyzed by a nonlinear least squares peak fitting program which included a background search. Spin and parity assignments to observed excited levels were made by comparing experimental angular distributions with distorted wave Born approximation calculations.

  18. Ionic liquids behave as dilute electrolyte solutions

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  19. Electron transport in diborides: observation of superconductivity in ZrB sub 2

    Gasparov, V A; Zverkova, I I; Kulakov, M P

    2001-01-01

    Results on syntheses and electron transport properties of polycrystalline samples of diborides (AB sub 2) with different transition metals atoms (A = Zr, Nb, Ta) are reported. The temperature dependences of resistivity and ac susceptibility of these samples reveal superconducting transition of ZrB sub 2 with T sub c = 5.5 K, while NbB sub 2 and TaB sub 2 have been observed nonsuperconducting up to 0.37 K. The upper critical field H sub c sub 2 (T) is linear in temperature below T sub c. At T close to T sub c H sub c sub 2 (T) demonstrates a downward curvature. It is concluded that these diborides as well as MgB sub 2 samples behave like simple metals in the normal state with usual Bloch-Grueneisen temperature dependence of resistivity and with Debye temperatures: 280, 460 and 440 K, for ZrB sub 2 , NbB sub 2 and MgB sub 2 , respectively

  20. Oxidation study of Ta–Zr coatings

    Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Chen, Sin-Min

    2013-02-01

    Refractory metal alloy coatings, such as Mo–Ru and Ta–Ru coatings, have been developed to protect glass molding dies. Forming intermetallic compounds in the coatings inhibits grain growth in high temperature environments when mass producing optical components. After annealing in oxygen containing atmospheres, a surface roughening of the Mo–Ru coatings and a soft oxide layer on the Ta–Ru coatings have been observed in our previous works. Oxidation resistance becomes critical in high-temperature applications. In this study, Ta–Zr coatings were deposited with a Ti interlayer on silicon wafers using direct current magnetron sputtering at 400 °C. The as-deposited Ta–Zr coatings possessed nanocrystallite or amorphous states, depending on the chemical compositions. The annealing treatments were conducted at 600 °C under atmospheres of 50 ppm O{sub 2}–N{sub 2} or 1% O{sub 2}–Ar, respectively. After the annealing treatment, this study investigated variations in crystalline structure, hardness, surface roughness, and chemical composition profiles. Preferential oxidation of Zr in the Ta–Zr coatings was verified using X-ray photoelectron spectroscopy, and the microstructure was observed using transmission electron microscopy. - Highlights: ►The as-deposited Ta-rich Ta–Zr coatings revealed an amorphous structure. ►The Zr-rich coatings presented a crystalline β-Zr phase and an amorphous matrix. ►Zr oxidized preferentially as Ta–Zr coatings annealed at 600 °C. ►The hardness of coatings revealed a parabolic relationship with the oxygen content. ►A protective oxide scale formed on the surface of the crystallized Zr-rich coatings.

  1. Perspective-takers behave more stereotypically.

    Galinsky, Adam D; Wang, Cynthia S; Ku, Gillian

    2008-08-01

    Nine studies demonstrated that perspective-takers are particularly likely to adopt a target's positive and negative stereotypical traits and behaviors. Perspective-takers rated both positive and negative stereotypic traits of targets as more self-descriptive. As a result, taking the perspective of a professor led to improved performance on an analytic task, whereas taking the perspective of a cheerleader led to decreased performance, in line with the respective stereotypes of professors and cheerleaders. Similarly, perspective-takers of an elderly target competed less compared to perspective-takers of an African American target. Including the stereotype in the self (but not liking of the target) mediated the effects of perspective-taking on behavior, suggesting that cognitive and not affective processes drove the behavioral effects. These effects occurred using a measure and multiple manipulations of perspective-taking, as well as a panoply of stereotypes, establishing the robustness of the link between perspective-taking and stereotypical behavior. The findings support theorizing (A. D. Galinsky, G. Ku, & C. S. Wang, 2005) that perspective-takers utilize information, including stereotypes, to coordinate their behavior with others and provide key theoretical insights into the processes of both perspective-taking and behavioral priming. (c) 2008 APA, all rights reserved

  2. Interdiffusion and reaction between U and Zr

    Park, Y.; Newell, R.; Mehta, A.; Keiser, D. D.; Sohn, Y. H.

    2018-04-01

    The microstructural development and diffusion kinetics were examined for the binary U vs. Zr system using solid-to-solid diffusion couples, U vs. Zr, annealed at 580 °C for 960 h, 650 °C for 480 h, 680 °C for 240 h, and 710 °C for 96 h. Scanning and transmission electron microscopies with X-ray energy dispersive spectroscopy were employed for detailed microstructural and compositional analyses. Interdiffusion and reaction in U vs. Zr diffusion couples primarily produced: δ-UZr2 solid solution (hP3) and α‧-U at 580 °C; and (γU,βZr) solid solution (cI2) and α‧-U at 650°, 680° and 710 °C. The α‧-phase was confirmed as a reduced variant of the α-U orthorhombic structure with lattice parameters, a × b × c = 2.65 × 5.40 × 4.75 (Å) with a negligible solubility for Zr at room temperature. Concentration profiles were examined to determine interdiffusion coefficients, integrated interdiffusion coefficients, and intrinsic diffusion coefficients using Boltzmann-Matano, Wagner, and Heumann analyses, respectively. Composition-dependence of interdiffusion coefficients were documented for α-U, δ-UZr2 (at 580 °C) and (γU,βZr) solid solution (at 650°, 680° and 710 °C). U was determined to intrinsically diffuse faster than Zr, approximately by an order of magnitude, in the δ-UZr2 at 580 °C, and (γU,βZr) phases at 650°, 680° and 710 °C. Based on Darken's approach, thermodynamic data available in literature were coupled to estimate the tracer diffusion coefficients and atomic mobilities of U and Zr.

  3. Density functional study of vibrational, thermodynamic and elastic properties of ZrCo and ZrCoX3 (X = H, D and T) compounds

    Chattaraj, D.; Parida, S.C.; Dash, Smruti; Majumder, C.

    2015-01-01

    Highlights: • The physico-chemical properties of ZrCo and its hydrides were studied. • The isotope effect on vibrational and thermodynamic properties was investigated. • The changes in elastic properties due to hydrogenation of ZrCo were investigated. • Thermodynamics properties of ZrCo and its hydrides were calculated. - Abstract: The dynamical, thermodynamic and elastic properties of ZrCo and its hydrides ZrCoX 3 (X = H, D and T) are reported. While the electronic structure calculations are performed using plane wave pseudopotential approach, the effect of isotopes on the vibrational and thermodynamic properties has been demonstrated through frozen phonon approach. The results reveal significant difference between the ZrCoH 3 and its isotopic analogs in terms of phonon frequencies and zero point energies. For example, the energy gap between optical and acoustic modes reduces in the order of ZrCoT 3 > ZrCoD 3 > ZrCoH 3 . The vibrational properties shows that the intermetallic ZrCo is dynamically stable whereas ZrCoX 3 (X = H, D and T) are dynamically unstable. The calculated formation energies of ZrCoX 3 , including the ZPE, are −146.7, −158.3 and −164.1 kJ/(mole of ZrCoX 3 ) for X = H, D and T, respectively. In addition, the changes in elastic properties of ZrCo upon hydrogenation have also been investigated. The results show that both ZrCo and ZrCoH 3 are mechanically stable at ambient pressure. The Debye temperatures of both ZrCo and ZrCoH 3 are determined using the calculated elastic moduli

  4. Density functional study of vibrational, thermodynamic and elastic properties of ZrCo and ZrCoX{sub 3} (X = H, D and T) compounds

    Chattaraj, D., E-mail: debchem@barc.gov.in [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Parida, S.C.; Dash, Smruti [Product Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Majumder, C. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-04-25

    Highlights: • The physico-chemical properties of ZrCo and its hydrides were studied. • The isotope effect on vibrational and thermodynamic properties was investigated. • The changes in elastic properties due to hydrogenation of ZrCo were investigated. • Thermodynamics properties of ZrCo and its hydrides were calculated. - Abstract: The dynamical, thermodynamic and elastic properties of ZrCo and its hydrides ZrCoX{sub 3} (X = H, D and T) are reported. While the electronic structure calculations are performed using plane wave pseudopotential approach, the effect of isotopes on the vibrational and thermodynamic properties has been demonstrated through frozen phonon approach. The results reveal significant difference between the ZrCoH{sub 3} and its isotopic analogs in terms of phonon frequencies and zero point energies. For example, the energy gap between optical and acoustic modes reduces in the order of ZrCoT{sub 3} > ZrCoD{sub 3} > ZrCoH{sub 3}. The vibrational properties shows that the intermetallic ZrCo is dynamically stable whereas ZrCoX{sub 3} (X = H, D and T) are dynamically unstable. The calculated formation energies of ZrCoX{sub 3}, including the ZPE, are −146.7, −158.3 and −164.1 kJ/(mole of ZrCoX{sub 3}) for X = H, D and T, respectively. In addition, the changes in elastic properties of ZrCo upon hydrogenation have also been investigated. The results show that both ZrCo and ZrCoH{sub 3} are mechanically stable at ambient pressure. The Debye temperatures of both ZrCo and ZrCoH{sub 3} are determined using the calculated elastic moduli.

  5. ZrB₂-CNTs Nanocomposites Fabricated by Spark Plasma Sintering.

    Jin, Hua; Meng, Songhe; Xie, Weihua; Xu, Chenghai; Niu, Jiahong

    2016-11-29

    ZrB₂-based nanocomposites with and without carbon nanotubes (CNTs) as reinforcement were prepared at 1600 °C by spark plasma sintering. The effects of CNTs on the microstructure and mechanical properties of nano-ZrB₂ matrix composites were studied. The results indicated that adding CNTs can inhibit the abnormal grain growth of ZrB₂ grains and improve the fracture toughness of the composites. The toughness mechanisms were crack deflection, crack bridging, debonding, and pull-out of CNTs. The experimental results of the nanograined ZrB₂-CNTs composites were compared with those of the micro-grained ZrB₂-CNTs composites. Due to the small size and surface effects, the nanograined ZrB₂-CNTs composites exhibited stronger mechanical properties: the hardness, flexural strength and fracture toughness were 18.7 ± 0.2 GPa, 1016 ± 75 MPa, and 8.5 ± 0.4 MPa·m 1/2 , respectively.

  6. Zr-Sn-Nb alloys. Preliminary studies

    Danon, C.A.; Arias, D.E.

    1993-01-01

    Studies of the Zr-Sn-Nb diagram have been started, focussing on the Zr-rich corner, near the composition of Zirlo commercial alloy, Zr-1Sn-1Nb, and with Fe and O contents usual in nuclear grade materials. Three alloys were melted, namely Zr-4Sn-2.4Nb (A), Zr-1Sn-3Nb (B) and Zr-2.1Sn-1Nb (C). α/β transformation temperatures were measured through the variation of electrical resistivity(p) vs temperature (T). Values of 560 deg C, 670 deg C and 750 deg C were measured for the α→α+β reaction and 980 deg C, 910 deg C and 1000 deg C for the α+β→β reaction, for the A, B and C alloys, respectively in that order. Some samples were submitted to heat treatments (62 and 216 hours at 825 deg C, 120 hours at 875 deg C). Optical and scanning electronic microscopy of those samples confirmed our resistivity results. (Author)

  7. Creep properties of Nb-1Zr and Nb-1Zr-0.1C

    Horak, J.A.; Egner, L.K.

    1994-12-01

    In the early 1980s a compact, lithium cooled, fast-energy spectrum nuclear reactor was selected for space applications requiring prolonged uninterrupted electrical power. This reactor was to be capable of generating up to 100 kilowatts of electricity for times up to seven years in space and thus was given the acronym SP-100. The material selected for the fuel cladding, reactor heat transport systems and structural components was Nb-1 wt % Zr (Nb-1Zr). In addition to commercial Nb-1Zr, modified alloys containing 100--200 wt ppM each of carbon and nitrogen and 900 ± 150 wt ppM carbon were also included, Type B Nb-1Zr and PWC-11, respectively. The SP-100 reactor was designed to operate at temperatures of 1290--1425 K. At these temperatures the principal mode of deformation for Nb-1Zr is creep, and creep strain of the fuel cladding limits the useful reactor lifetime. To develop a creep data base for design, safety and reliability analyses, uniaxial creep testing of Nb-1Zr, Type B Nb-1Zr and PWC-11 was conducted from 1250--1450 K at stresses from 5.0 MPa to 41.4 MPa. Methodology and test results are presented

  8. Concurrent reflectance imaging and microdialysis in the freely behaving cat

    Poe, G R; Nitz, D A; Rector, D M

    1996-01-01

    We present a method to perform simultaneous microdialysis with light reflectance imaging of neural activity in a discrete brain region of the freely behaving animal. We applied this method to the dorsal hippocampus of freely behaving cats to (1) measure extracellular glutamate and reflectance...... imaged neural activity. Sequential images showed that cocaine perfusion elicited a propagating reflectance change as cocaine reached the tissue. Microperfusion of hypo-osmotic solution ( - 100 mOsm), which increases cell volume, decreased reflectance. Microperfusion of hyperosmotic sucrose solutions...

  9. Nanotube morphology changes for Ti-Zr alloys as Zr content increases

    Kim, Won-Gi; Choe, Han-Cheol; Ko, Yeong-Mu; Brantley, William A.

    2009-01-01

    Nanotube morphology changes in Ti-Zr alloys as Zr content increases have been investigated. Ti-Zr (10, 20, 30 and 40 wt.%) alloys were prepared by arc melting and heat treated for 24 h at 1000 o C in an argon atmosphere. TiO 2 nanotubes were formed on the Ti-Zr alloys by anodization in H 3 PO 4 containing 0.5 wt.% NaF. Electrochemical experiments were performed using a conventional three-electrode configuration with a platinum counter electrode and a saturated calomel reference electrode. Samples were embedded in epoxy resin, leaving an area of 10 mm 2 exposed to the electrolyte. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. Microstructures of the alloys were examined by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and x-ray diffraction (XRD). The Ti-Zr alloy microstructures observed by OM and FE-SEM changed from a lamellar structure to a needle-like structure with increasing Zr content. The microstructures also changed from β phase to increasing amounts of α phase as the Zr content increased. The number of large nanotubes formed by anodization decreased, and the number of small nanotubes increased, as the Zr content increased. The mean inner diameter ranged from approximately 150 to 200 nm with a tube-wall thickness of about 20 nm. The interspace between the nanotubes was approximately 60, 70, 100 and 130 nm for Zr contents of 10, 20, 30 and 40 wt.%, respectively.

  10. Calculation of Gibbs energy of Zr-Al-Ni, Zr-Al-Cu, Al-Ni-Cu and Zr-Al-Ni-Cu liquid alloys based on quasiregular solution model

    Li, H.Q.; Yang, Y.S.; Tong, W.H.; Wang, Z.Y.

    2007-01-01

    With the effects of electronic structure and atomic size being introduced, the mixing enthalpy as well as the Gibbs energy of the ternary Zr-Al-Cu, Ni-Al-Cu, Zr-Ni-Al and quaternary Zr-Al-Ni-Cu systems are calculated based on quasiregular solution model. The computed results agree well with the experimental data. The sequence of Gibbs energies of different systems is: G Zr-Al-Ni-Cu Zr-Al-Ni Zr-Al-Cu Cu-Al-Ni . To Zr-Al-Cu, Ni-Al-Cu and Zr-Ni-Al, the lowest Gibbs energy locates in the composition range of X Zr 0.39-0.61, X Al = 0.38-0.61; X Ni = 0.39-0.61, X Al = 0.38-0.60 and X Zr = 0.32-0.67, X Al = 0.32-0.66, respectively. And to the Zr-Ni-Al-Cu system with 66.67% Zr, the lowest Gibbs energy is obtained in the region of X Al = 0.63-0.80, X Ni = 0.14-0.24

  11. A Comparative Discussion of the Catalytic Activity and CO2-Selectivity of Cu-Zr and Pd-Zr (Intermetallic Compounds in Methanol Steam Reforming

    Norbert Köpfle

    2017-02-01

    Full Text Available The activation and catalytic performance of two representative Zr-containing intermetallic systems, namely Cu-Zr and Pd-Zr, have been comparatively studied operando using methanol steam reforming (MSR as test reaction. Using an inverse surface science and bulk model catalyst approach, we monitored the transition of the initial metal/intermetallic compound structures into the eventual active and CO2-selective states upon contact to the methanol steam reforming mixture. For Cu-Zr, selected nominal stoichiometries ranging from Cu:Zr = 9:2 over 2:1 to 1:2 have been prepared by mixing the respective amounts of metallic Cu and Zr to yield different Cu-Zr bulk phases as initial catalyst structures. In addition, the methanol steam reforming performance of two Pd-Zr systems, that is, a bulk system with a nominal Pd:Zr = 2:1 stoichiometry and an inverse model system consisting of CVD-grown ZrOxHy layers on a polycrystalline Pd foil, has been comparatively assessed. While the CO2-selectivity and the overall catalytic performance of the Cu-Zr system is promising due to operando formation of a catalytically beneficial Cu-ZrO2 interface, the case for Pd-Zr is different. For both Pd-Zr systems, the low-temperature coking tendency, the high water-activation temperature and the CO2-selectivity spoiling inverse WGS reaction limit the use of the Pd-Zr systems for selective MSR applications, although alloying of Pd with Zr opens water activation channels to increase the CO2 selectivity.

  12. hnRNPs H, H' and F behave differently with respect to posttranslational cleavage and subcellular localization

    Honoré, B; Vorum, H; Baandrup, U

    1999-01-01

    cytoplasmic localization in other cells. The different fates may reflect differences in functional roles that so far only have included nuclear functions. The presence of significant quantities of hnRNP F in the cytoplasm of many cells indicates that it also may have a functional role here. Udgivelsesdato...

  13. Almost 'magnetic dead' of the Co layer in Co/Zr sub 3 superlattice

    Kwon, Y S; Hong, S C; Lee, Y P

    1999-01-01

    The magnetic and electronic properties of Co/Zr sub 3 (0001) superlattice and unsupported Co and Zr monolayers (ML) with the hcp bulk Zr two dimensional lattice parameters have been calculated by employing the full potential linearized augmented plane wave (FLAPW) method with general gradient approximation (GGA) for exchange-correlation potential. The unsupported Zr and Co ML were calculated to be stable in paramagnetic and ferromagnetic states, respectively. The magnetic moment of the unsupported Co ML was 2.08 mu B. The Co-Zr interlayer spacing of the Co/Zr sub 3 superlattice was calculated to be reduced significantly by 9.80 % compared to that expected from Co and Zr bulk assuming preservation of the atomic volumes. On the other hand, the Zr-Zr interlayer spacing was calculated to be enhanced by 3.35 % compared to that of bulk Zr. Both of the reduced Zr-Co and the enhanced Zr-Zr interlayer spacings decreased the magnetic moment of Co and eventually led to almost 'magnetic dead' (0.33 mu B). Surprisingly, t...

  14. The 91Zr(d,t)90Zr reaction

    Gomes, L.C.

    1975-01-01

    Sixteen levels populated in the 91 Zr(d,t) 90 Zr pick-up reaction were studied with 16 MeV deuterons. Distorted waves Born approximation calculations were compared to the data, and yielded spectroscopic factors and l values. Particle-hole states in 90 Zr were observed. Some significant errors were found in Zr(d,t) reactions Q values recently compiled [pt

  15. A Novel Distributed Quantum-Behaved Particle Swarm Optimization

    Yangyang Li

    2017-01-01

    Full Text Available Quantum-behaved particle swarm optimization (QPSO is an improved version of particle swarm optimization (PSO and has shown superior performance on many optimization problems. But for now, it may not always satisfy the situations. Nowadays, problems become larger and more complex, and most serial optimization algorithms cannot deal with the problem or need plenty of computing cost. Fortunately, as an effective model in dealing with problems with big data which need huge computation, MapReduce has been widely used in many areas. In this paper, we implement QPSO on MapReduce model and propose MapReduce quantum-behaved particle swarm optimization (MRQPSO which achieves parallel and distributed QPSO. Comparisons are made between MRQPSO and QPSO on some test problems and nonlinear equation systems. The results show that MRQPSO could complete computing task with less time. Meanwhile, from the view of optimization performance, MRQPSO outperforms QPSO in many cases.

  16. Structure of zirconium-93 and zirconium-91 as shown by the reactions Zr-92(d,p)Zr-93 and Zr-92(d,t)Zr-91

    Baron, N.; Leonard, R. F.; Stewart, W. M.; Fink, C. L.; Christensen, P. R.; Nickles, J.; Thorsteinsen, T. F.

    1972-01-01

    Deuterons of 13-MeV incident energy were scattered from Zr-92(d,p)Zr-93. The Zr-92(d,p)Zr-93 data analysis resulted in the location of 47 levels up to an excitation energy of 4.84 MeV, and the spins of 43 of these levels were identified. Essentially all the strength of the 2d5/2, 3s1/2, 2d3/2, and 1g7/2 shells was observed; and the excitation energy of their centroids was computed to be 0.00, 1.21, 2.23, and 2.37 MeV, respectively. Also, 43 percent of the 1h11/2 strength, 21 percent of the 2f7/2 strength, and 3 percent of the 3p3/2 strength were observed. In addition, the Zr-92(d,t)Zr-91 data analysis resulted in the location of 26 levels up to an excitation energy of 4.01 MeV, and the spins of 21 of these levels were identified. Most of the expected strength of the 2d5/2 and 1g9/2 shells was obtained, and the excitation energy of their centroids was computed to be 0.31 and 3.19 MeV, respectively. In addition, six l=1 states are populated belonging to either the 2p1/2 or 2p3/2 shells.

  17. Effect of Zr addition on phase constitution and heat treatment behavior of Ti-25mass%Nb alloys

    Ikeda, M.; Mori, M.; Hirasawa, T.; Toyoshima, K.

    2005-01-01

    In an attempt to optimize the shape recovery temperature, the effect of Zr addition on phase constitution and heat treatment behavior is investigated by electrical resistivity and Vickers hardness (HV) measurements, X-ray diffractometry (XRD) and shape recovery tests. Ti-25mass%Nb-0, 2, 7 and 12mass%Zr alloys (abbreviated as 0Zr, 2Zr, 7Zr and 12Zr, respectively) were prepared using an arc-furnace. Specimens were solution-treated at 1273 K for 3.6 ks and then quenched by iced water (STQ). STQed specimens were isochronally heat-treated. In 0Zr and 2Zr, only the orthorhombic martensite phase α '' was identified by XRD, while the two-phase alloys α '' and β were identified in 7Zr and 12Zr. In 7Zr, resistivity at liquid nitrogen and room temperature (ρ LN and ρ RT , respectively) and resistivity ratio (ρ LN /ρ RT ) drastically increased at 523 K because of the reverse-transformation of α '' into β phase. Thereafter, resistivity and resistivity ratio decreased with increasing heat treatment temperature due to isothermal ω precipitation. Starting temperature of shape recovery is 623 K in 7Zr and 523 K in 12Zr. In 7Zr, shape recovery ratio is about 80% at 723 K, which is the maximum obtained in this study. (orig.)

  18. Respect changes your life!

    Alizée Dauvergne

    2010-01-01

    CERN has recently joined the Geneva-based association "Le respect, ça change la vie" (Respect can change our lives). As its name suggests, the association promotes respect, in all its forms. This decision will enable CERN to share some of its values, those it has in common with the association, with the community at large.   The new bilingual logo of the "Le respect ça change la vie" association. "CERN has been a member of the Geneva-based association "Le respect, ça change la vie" since March," says Friedemann Eder, Head of the Relations with the Host States Service. Mutual respect, respecting the differences and the work of others, respect on the road, in the family, at school, etc. The association, which was founded in 2003 and now has a large number of members, promotes this universal value and encourages discussion on it. "CERN's history shows the importance and success o...

  19. Respect in Education

    Giesinger, Johannes

    2012-01-01

    This article discusses the educational significance of the moral demand for respect. In "Ethics and Education," Richard Peters presents a conception of educational respect that was recently taken up by Krassimir Stojanov. This article responds to both Peters' and Stojanov's contributions and proposes another understanding of educational respect:…

  20. Amorphous Ti-Zr

    Rabinkin, A.; Liebermann, H.; Pounds, S.; Taylor, T.

    1991-01-01

    This paper is the first report on processing, properties and potential application of amorphous titanium/zirconium-base alloys produced in the form of a good quality continuous and ductile ribbon having up to 12.5 mm width. To date, the majority of titanium brazing is accomplished using cooper and aluminum-base brazing filler metals. The brazements produced with these filler metals have rather low (∼300 degrees C) service temperature, thus impeding progress in aircraft and other technologies and industries. The attempt to develop a generation of high temperature brazing filler metals was made in the late sixties-early seventies studies in detail were a large number of Ti-, Zr-Ti-Zr, Ti-V and Zr-V-Ti based alloys. The majority of these alloys has copper and nickel as melting temperature depressants. The presence of nickel and copper converts them into eutectic alloys having [Ti(Zr)] [Cu(Ni)], intermetallic phases as major structural constituents. This, in turn, results in high alloy brittleness and poor, if any, processability by means of conventional, i.e. melting-ingot casting-deformation technology. In spite of good wettability and high joint strength achieved in dozens of promising alloys, only Ti-15Cu-15Ni is now widely used as a brazing filler metal for high service temperature. Up until now this material could not be produced as a homogeneous foil and is instead applied as a clad strip consisting of three separate metallic layers

  1. Anticipating and Resisting the Temptation to Behave Unethically.

    Sheldon, Oliver J; Fishbach, Ayelet

    2015-07-01

    Ethical dilemmas pose a self-control conflict between pursuing immediate benefits through behaving dishonestly and pursuing long-term benefits through acts of honesty. Therefore, factors that facilitate self-control for other types of goals (e.g., health and financial) should also promote ethical behavior. Across four studies, we find support for this possibility. Specifically, we find that only under conditions that facilitate conflict identification--including the consideration of several decisions simultaneously (i.e., a broad decision frame) and perceived high connectedness to the future self--does anticipating a temptation to behave dishonestly in advance promote honesty. We demonstrate these interaction patterns between conflict identification and temptation anticipation in negotiation situations (Study 1), lab tasks (Study 2), and ethical dilemmas in the workplace (Studies 3-4). We conclude that identifying a self-control conflict and anticipating a temptation are two necessary preconditions for ethical decision making. © 2015 by the Society for Personality and Social Psychology, Inc.

  2. Corrosion and deuterium uptake of Zr-based alloys in supercritical water

    Khatamian, D.

    2010-01-01

    To increase the thermodynamic efficiency above 40% in nuclear power plants, the use of supercritical water as the heat transport fluid has been suggested. Zircaloy-2, -4, Zr-Cr-Fe, Zr-1Nb and Zr-2.5Nb were tested as prospective fuel cladding materials in 30 MPa D 2 O at 500 o C. Zircaloy-2 showed the highest rates of corrosion and hydriding. Although Zr-Cr-Fe initially showed a very low corrosion rate, it displayed breakaway corrosion kinetics after 50 h exposure. The best-behaved material both from a corrosion and hydrogen uptake point of view was Zr-2.5Nb. However, the Zr-2.5Nb oxide growth rate was still excessive and beyond the current CANDU design allowance. Similar coupons, coated with Cr, were also tested. The coated layer effectively prevented oxidation of the coupons except on the edges, where the coating was thinner and had some flaws. In addition, the Cr-coated Zr-2.5Nb coupons had the lowest deuterium pickup of all the alloys tested and showed no signs of accelerated or nonuniform corrosion. (author)

  3. Zirconium Zr and hafnium Hf

    Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

    1978-01-01

    The basic methods for extracting and determining Zr(4) and Hf(4) are described. Diantipyrinemethane and its alkyl homologs selectively extract Zr and Hf from HNO 3 solutions in the presence of nitrates. Zr is selectively extracted with tetraethyldiamide of heptyl phosphoric acid (in benzene) as well as with 2-thenoyltrifluoroacetone (in an acid). The latter reagents is suitable for rapid determination of 95 Zr in a mixture with 95 Nb and other fragments. The complexometric determination of Zr is based on formation of a stable complex of Zr with EDTA. The titration is carried out in the presence of n-sulfobenzene-azo-pyrocatechol, eriochrome black T. The determination is hindered by Hf, fluoride-, phosphate-, oxalate- and tartrate-ions. The method is used for determining Zr in zircon and eudialyte ore. Zr is determined photometrically with the aid of xylenol orange, arsenazo 3 and pyrocatechol violet (in phosphorites). Hf is determined in the presence of Zr photometrically with the aid of xylenol orange or methyl-thymol blue. The method is based on Zr being masked with hydrogen peroxide in the presence of sulfate-ions

  4. Respect for rational autonomy.

    Walker, Rebecca L

    2009-12-01

    The standard notion of autonomy in medical ethics does not require that autonomous choices not be irrational. The paper gives three examples of seemingly irrational patient choices and discusses how a rational autonomy analysis differs from the standard view. It then considers whether a switch to the rational autonomy view would lead to overriding more patient decisions but concludes that this should not be the case. Rather, a determination of whether individual patient decisions are autonomous is much less relevant than usually considered in determining whether health care providers must abide by these decisions. Furthermore, respect for rational autonomy entails strong positive requirements of respect for the autonomy of the person as a rational decision maker. The rationality view of autonomy is conceptually stronger than the standard view, allows for a more nuanced understanding of the practical moral calculus involved in respecting patient autonomy, and promotes positive respect for patient autonomy.

  5. Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

    Ramos, C.P. [CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)]. E-mail: ciramos@cnea.gov.ar; Granovsky, M.S. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Saragovi, C. [CAC-CNEA, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)

    2007-02-01

    The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb){sub 2} and (ZrNb)Fe{sub 2}) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic {beta} phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr){sub 2} compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases.

  6. Moessbauer spectroscopy characterization of Zr-Nb-Fe phases

    Ramos, C.P.; Granovsky, M.S.; Saragovi, C.

    2007-01-01

    The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Moessbauer spectroscopy. This is part of a complete study involving a tentative isothermal section at 900 deg. C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at% and Fe contents between 10 and 60 at% were analyzed after a heat treatment at 900 deg. C for 4 month. Moessbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb) 2 and (ZrNb)Fe 2 ) sees different environments, producing quadrupole splitting and hyperfine field distributions, respectively. Two types of body centered cubic β phases (Zr-rich and Nb-rich) were found having noticeable differences in their Moessbauer parameters. Furthermore it was shown that the ternary Fe(NbZr) 2 compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases

  7. The olfactory tubercle encodes odor valence in behaving mice.

    Gadziola, Marie A; Tylicki, Kate A; Christian, Diana L; Wesson, Daniel W

    2015-03-18

    Sensory information acquires meaning to adaptively guide behaviors. Despite odors mediating a number of vital behaviors, the components of the olfactory system responsible for assigning meaning to odors remain unclear. The olfactory tubercle (OT), a ventral striatum structure that receives monosynaptic input from the olfactory bulb, is uniquely positioned to transform odor information into behaviorally relevant neural codes. No information is available, however, on the coding of odors among OT neurons in behaving animals. In recordings from mice engaged in an odor discrimination task, we report that the firing rate of OT neurons robustly and flexibly encodes the valence of conditioned odors over identity, with rewarded odors evoking greater firing rates. This coding of rewarded odors occurs before behavioral decisions and represents subsequent behavioral responses. We predict that the OT is an essential region whereby odor valence is encoded in the mammalian brain to guide goal-directed behaviors. Copyright © 2015 the authors 0270-6474/15/354515-13$15.00/0.

  8. High pressure phase transitions and compressibilities of Er2Zr2O7 and Ho2Zr2O7

    Zhang, F. X.; Lang, M.; Becker, U.; Ewing, R. C.; Lian, J.

    2008-01-01

    Phase stability and compressibility of rare earth zirconates with the defect-fluorite structure were investigated by in situ synchrotron x-ray diffraction. A sluggish defect-fluorite to a cotunnitelike phase transformation occurred at pressures of ˜22 and ˜30GPa for Er2Zr2O7 and Ho2Zr2O7, respectively. Enhanced compressibility was found for the high pressure phase as a result of increasing cation coordination number and cation-anion bond length.

  9. High Pressure Phase Transitions and Compressibilities of Er2Zr2O7 and Ho2Zr2O7

    Zhang,F.; Lang, M.; Becker, U.; Ewing, R.; Lian, J.

    2008-01-01

    Phase stability and compressibility of rare earth zirconates with the defect-fluorite structure were investigated by in situ synchrotron x-ray diffraction. A sluggish defect-fluorite to a cotunnitelike phase transformation occurred at pressures of {approx} 22 and {approx} 30 GPa for Er2Zr2O7 and Ho2Zr2O7, respectively. Enhanced compressibility was found for the high pressure phase as a result of increasing cation coordination number and cation-anion bond length.

  10. Proposal of guideline for bonding to prevention of hydrogen embrittlement at Ta/Zr bond interface. Hydrogen embrittlement in SUS304ULC/Ta/Zr explosive bonded joint

    Saida, Kazuyoshi; Fujimoto, Tetsuya; Nishimoto, Kazutoshi

    2010-01-01

    The occurrence condition of hydrogen embrittlement cracking at Ta/Zr bond interface was investigated with respect to the hydrogen content and applied stress in order to propose a guideline for the explosive bonding procedure to prevention of hydrogen embrittlement. Hydrogen charging test was conducted for SUS304ULC/Ta/Zr explosive bonded joints applied the different flexural strains. A hydrogen embrittlement crack occurred in the Zr substrate at Ta/Zr bond interface after hydrogen charging, and it was initiated at shorter charging times when the augmented strain was increased. The occurrence condition of hydrogen embrittlement cracking at Ta/Zr bond interface was shifted to lower stress and hydrogen content with an increase in the amount of explosive during bonding. It was suggested that hydrogen embrittlement in Ta/Zr explosive bonded joint could be inhibited by reducing the initial hydrogen content in Ta substrate less than approx. 5 ppm. (author)

  11. Thermoluminescence on ZrO{sub 2} films with different dopants; Termoluminiscencia en peliculas de ZrO{sub 2} con distintos impurificantes

    Ceron R, P. V.; Rivera M, T.; Ramos G, A. I.; Guzman M, J.; Montes R, E., E-mail: victceronr@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The metal oxides doped with rare earths have presented good thermoluminescent properties for certain wavelengths in the UV. With respect to zirconium oxide exist several studies in which were incorporated impurities and their properties as dosimeter in several regions of the electromagnetic spectrum were analyzed. Because of this background, in this material thermoluminescent glow curves induced by UV in films of ZrO{sub 2}:Eu and ZrO{sub 2}:Tb were studied for comparison with the response of the material doped with two rare earths (ZrO{sub 2}:Eu + Tb). Samples were deposited on glass by ultrasonic spray pyrolysis technique with different synthesis parameters. It was found that the strongest Tl response was to ZrO{sub 2} film doped with terbium (14 times more intense than the film of ZrO{sub 2}:Eu and 6 times the response of ZrO{sub 2}:Eu + Tb). (Author)

  12. Study on surface defect structures of ZrO2 and some doped ZrO2 by means of work function measurement

    Yamawaki, M.; Suzuki, A.; Ono, F.; Yamaguchi, K.

    1997-01-01

    The work function change of the ZrO 2 +2%Y 2 O 3 sintered pellet, caused by a change of the composition of the sweep gas, was measured using a high temperature Kelvin probe. The Pt reference electrode was calibrated by using ZrO 2 +2%Y 2 O 3 as a standard material. Work function changes of undoped ZrO 2 and Nb-doped ZrO 2 (2%Nb 2 O 5 ) were measured as a function of equilibrium oxygen partial pressure, P O 2 . The thus obtained exponents of P O 2 , 1/n, were 1/6.2 and 1/33.6 for ZrO 2 and ZrO 2 +2%Nb 2 O 5 , respectively. These exponent values were discussed in terms of defect chemistry of the surface layer. (orig.)

  13. Toleration out of respect?

    Lægaard, Sune

    2013-01-01

    Under conditions of pluralism different cultures, interests or values can come into conflict, which raises the problem of how to secure peaceful co-existence. The idea of toleration historically emerged as an answer to this problem. Recently Rainer Forst has argued that toleration should not just...... be based on a modus vivendi designed to secure peaceful co-existence, but should be based on moral reasons. Forst therefore advances what he calls the ‘respect conception’ of toleration as an in itself morally desirable type of relationship, which is furthermore the only conception of toleration...... that avoids various so-called ‘paradoxes of toleration’. The paper first examines whether Forst’s respect conception can be applied descriptively to distinguish between actual patterns of behaviour and classify different acts of toleration. Then the focus is shifted to toleration out of respect as a normative...

  14. Ombud's Corner: Respect @ CERN

    Sudeshna Datta-Cockerill

    2014-01-01

    Since 2010 CERN has been a member of the Geneva-based association "Le respect, ça change la vie". Four years later and in conjunction with CERN’s celebration of its 60 years of ‘science for peace’, it is time to launch a new respectful workplace awareness campaign under the auspices of the Ombud.   Mutual respect is a basic pillar of peace. At CERN, we pride ourselves on our history, which started when a handful of Europe’s visionary scientists saw the opportunity that an international laboratory for fundamental research would present in bringing nations together. That idea has worked very well and, today, our success can be measured not only in terms of unprecedented scientific achievements but also in terms of training and education, and exemplary collaboration across borders, cultures and an extensive range of differences. In order for history to continue along these positive lines, and coming back to the awareness campai...

  15. Respect as an Incentive

    Eriksson, Tor Viking; Villeval, Marie-Claire

    Assuming that people care not only about what others do but also on what others think, we study respect as a non-monetary source of motivation in a context where the length of the employment relationship is endogenous.  In our three-stage gift-exchange experiment, the employer can express respect...... by giving the employee costly symbolic rewards after observing his level of effort. This experiment sheds light on the extent to which symbolic rewards are used, how they affect employees' further effort, the duration of relationships, and the profits of employers. Furthermore, we study whether employers...

  16. Respect or resignation?

    Liveng, Anne

    2005-01-01

    Students in the social- and health care worker education must learn to show "understanding" and "respect" for the seniors they help. How difficult it is to go from theory to practise becomes painfully obvious the forst time a student empties a bed pan.......Students in the social- and health care worker education must learn to show "understanding" and "respect" for the seniors they help. How difficult it is to go from theory to practise becomes painfully obvious the forst time a student empties a bed pan....

  17. BehavePlus fire modeling system, version 5.0: Variables

    Patricia L. Andrews

    2009-01-01

    This publication has been revised to reflect updates to version 4.0 of the BehavePlus software. It was originally published as the BehavePlus fire modeling system, version 4.0: Variables in July, 2008.The BehavePlus fire modeling system is a computer program based on mathematical models that describe wildland fire behavior and effects and the...

  18. Toleration out of respect?

    Lægaard, Sune

    2014-01-01

    be based on a modus vivendi designed to secure peaceful co-existence, but should be based on moral reasons. Forst therefore advances what he calls the ‘respect conception’ of toleration as an in itself morally desirable type of relationship, which is furthermore the only conception of toleration...

  19. Effect of Si and Zr on the Microstructure and Properties of Al-Fe-Si-Zr Alloys

    Anna Morozova

    2017-11-01

    Full Text Available The effects of Si and Zr on the microstructure, microhardness and electrical conductivity of Al-Fe-Si-Zr alloys were studied. An increase in the Zr content over 0.3 wt. % leads to the formation of primary Al3Zr inclusions and also decreases mechanical properties. Therefore, the Zr content should not be more than 0.3 wt. %, although the smaller content is insufficient for the strengthening by the secondary Al3Zr precipitates. The present results indicate that high content of Si significantly affects the hardness and electrical conductivity of the investigated alloys. However, the absence of Si led to the formation of harmful needle-shaped Al3Fe particles in the microstructure of the investigated alloys after annealing. Therefore, the optimum amount of Si was 0.25–0.50 wt. % due to the formation of the Al8Fe2Si phase with the preferable platelet morphology. The maximum microhardness and strengthening effects in Al-1% Fe-0.25% Si-0.3% Zr were observed after annealing at 400–450 °C due to the formation of nanosized coherent Al3Zr (L12 dispersoids. The effect of the increasing of the electrical conductivity can be explained by the decomposition of the solid solution. Thus, Al-1% Fe-0.25% Si-0.3% Zr alloy annealed at 450 °C has been studied in detail as the most attractive with respect to the special focus on transmission line applications.

  20. Respect as an Incentive

    Eriksson, Tor Viking; Villeval, Marie-Claire

    whether employers’ decisions to give symbolic rewards are driven by strategic considerations. We find that employers do make use of symbolic rewards and chiefly to express their satisfaction with the employee. Symbolic rewards are associated with higher profits and increased probability of continuing......In this paper we examine respect as a non-monetary source of motivation. Our experiment sheds light on the extent to which symbolic rewards are used, how they are valued by the employees, and how they affect employee effort, the duration of relationships, and profits of employers. We also study...

  1. Synthesis and characterization of nanostructured CaZrO{sub 3} and BaZrO{sub 3}

    Ibiapino, Amanda Laura; Figueiredo, Laysa Pires de [Departamento de Quimica, Instituto de Ciencias Exatas e da Terra, Universidade Federal do Mato Grosso, MT (Brazil); Lascalea, Gustavo E. [LISAMEN/CONICET, Ciudad de Mendoza (Argentina); Prado, Rogerio Junqueira, E-mail: rjprado@ufmt.br [Instituto de Fisica, Universidade Federal do Mato Grosso, Cuiaba - MT (Brazil)

    2013-09-01

    In this work, nanostructured samples of barium zirconate (BaZrO{sub 3}) and calcium zirconate (CaZrO{sub 3}) were synthesized by the gel-combustion method, using glycine as fuel. The ceramic powders were calcined at 550 Degree-Sign C for 2 h and subsequently heat treated at 1350 Degree-Sign C for 10 min (fast-firing). The X-ray diffraction technique was employed to identify and characterize the crystalline phases present in the synthesized powders, using the Rietveld method. Monophasic nanostructured samples of BaZrO{sub 3} and CaZrO{sub 3} presenting average crystallite sizes of around 8.5 and 10.3 nm, respectively, were found after fast-firing. (author)

  2. Pupils' reasons for learning and behaving and for not learning and behaving in English and maths lessons in a secondary school.

    Norwich, B

    1999-12-01

    There is renewed interest in motivation and school learning, though there has been relatively little theory-linked research in English schools. In the first stage, to explore pupils' reasons for learning and behaving and for not learning and behaving in English, maths and other subjects. In the second stage, to examine differences in reasons across subjects, for learning and behaving and for not learning and behaving for boys and girls in two year groups in one secondary school. Stage 1, 16 pupils in years 7, 8 and 9 in two London secondary schools; Stage 2, 267 pupils in years 7 and 9 in one of these schools. Stage 1--semi-structured interviews were conducted to elicit different kinds of reasons conceptualised in terms of the Deci & Ryan's (1985) framework of self-determination. From these elicited reasons, an inventory 'Why I Learn' was designed. Stage 2--the inventory was administered to identify reasons for learning and behaving and for not learning and behaving in English and maths. Parent introjected reasons were the highest for learning and behaving while teacher introjected and intrinsic reasons were the lowest. Intrinsic reasons were highest for not learning and behaving. Year group differences in reason levels were more significant than gender or subject differences. Reasons for learning and behaving were more differentiated from each other than reasons for not learning and behaving. The results are discussed in terms of their significance for self-determination theory, research into the conditions promoting greater self-determination in school learning and further development of the inventory for programme evaluation.

  3. Voluntary running enhances glymphatic influx in awake behaving, young mice.

    von Holstein-Rathlou, Stephanie; Petersen, Nicolas Caesar; Nedergaard, Maiken

    2018-01-01

    Vascular pathology and protein accumulation contribute to cognitive decline, whereas exercise can slow vascular degeneration and improve cognitive function. Recent investigations suggest that glymphatic clearance measured in aged mice while anesthetized is enhanced following exercise. We predicted that exercise would also stimulate glymphatic activity in awake, young mice with higher baseline glymphatic function. Therefore, we assessed glymphatic function in young female C57BL/6J mice following five weeks voluntary wheel running and in sedentary mice. The active mice ran a mean distance of 6km daily. We injected fluorescent tracers in cisterna magna of awake behaving mice and in ketamine/xylazine anesthetized mice, and later assessed tracer distribution in coronal brain sections. Voluntary exercise consistently increased CSF influx during wakefulness, primarily in the hypothalamus and ventral parts of the cortex, but also in the middle cerebral artery territory. While glymphatic activity was higher under ketamine/xylazine anesthesia, we saw a decrease in glymphatic function during running in awake mice after five weeks of wheel running. In summary, daily running increases CSF flux in widespread areas of the mouse brain, which may contribute to the pro-cognitive effects of exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Hypothesis: solid tumours behave as systemic metabolic dictators.

    Lee, Yang-Ming; Chang, Wei-Chun; Ma, Wen-Lung

    2016-06-01

    Current knowledge regarding mechanisms of carcinogenesis in human beings centres around the accumulation of genetic instability, amplified cellular signalling, disturbed cellular energy metabolism and microenvironmental regulation governed by complicated cell-cell interactions. In this article, we provide an alternative view of cancer biology. We propose that cancer behaves as a systemic dictator that interacts with tissues throughout the body to control their metabolism and eventually homeostasis. The mechanism of development of this endocrine organ-like tumour (EOLT) tissue might be the driving force for cancer progression. Here, we review the literature that led to the development of this hypothesis. The EOLT phenotype can be defined as a tumour that alters systemic homeostasis. The literature indicates that the EOLT phenotype is present throughout cancer progression. The feedback mechanism that governs the interaction between tumours and various organs is unknown. We believe that investigating the mechanism of EOLT development may advance the current knowledge of regulation within the tumour macroenvironment and consequently lead to new diagnostic methods and therapy. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  5. Intermetallic phases in the iron-rich region of the Zr-Fe phase diagram

    Granovsky, M.S. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales; Arias, D. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Dept. de Materiales

    1996-04-01

    Intermetallic phases in the Fe-rich region of the Zr-Fe system are studied by X-ray diffraction and optical and electron microscopy. The chemical composition of each phase has been quantitatively measured in a electron microprobe. The stable phases found in this region are ZrFe{sub 2}, Zr{sub 6}Fe{sub 23} and ({alpha}Fe). ZrFe{sub 2} is identified as a cubic Laves type phase (C15) and the ZrFe{sub 2}/ZrFe{sub 2}+Zr{sub 6}Fe{sub 23} boundary composition is 73{+-}1 at.% Fe. Zr{sub 6}Fe{sub 23} is a cubic phase of the Th{sub 6}Mn{sub 23} type and its composition is 80.0{+-}1.5 at.% Fe. The eutectic L{r_reversible}Zr{sub 6}Fe{sub 23}+{tau}-Fe transformation temperature and composition are 1325 C and 91{+-}1 at.% Fe, respectively. The solubility of Zr in {tau}-Fe at 1012 C is 500{+-}50 appm and 1000{+-}100 appm close to the eutectic temperature. (orig.).

  6. Intermetallic phases in the iron-rich region of the Zr-Fe phase diagram

    Granovsky, M.S.; Arias, D.

    1996-01-01

    Intermetallic phases in the Fe-rich region of the Zr-Fe system are studied by X-ray diffraction and optical and electron microscopy. The chemical composition of each phase has been quantitatively measured in a electron microprobe. The stable phases found in this region are ZrFe 2 , Zr 6 Fe 23 and (αFe). ZrFe 2 is identified as a cubic Laves type phase (C15) and the ZrFe 2 /ZrFe 2 +Zr 6 Fe 23 boundary composition is 73±1 at.% Fe. Zr 6 Fe 23 is a cubic phase of the Th 6 Mn 23 type and its composition is 80.0±1.5 at.% Fe. The eutectic L↔Zr 6 Fe 23 +τ-Fe transformation temperature and composition are 1325 C and 91±1 at.% Fe, respectively. The solubility of Zr in τ-Fe at 1012 C is 500±50 appm and 1000±100 appm close to the eutectic temperature. (orig.)

  7. AMS of 93Zr: Passive absorber versus gas-filled magnet

    Hain, Karin; Deneva, Boyana; Faestermann, Thomas; Fimiani, Leticia; Gómez-Guzmán, José Manuel; Koll, Dominik; Korschinek, Gunther; Ludwig, Peter; Sergeyeva, Victoria; Thiollay, Nicolas

    2018-05-01

    Two different isobar separation techniques were tested for the detection of the long-lived fission product 93Zr (T1/2 = 1.64 · 106 a) using Accelerator Mass Spectrometry (AMS), i.e. a passive absorber and a gas-filled magnet, respectively. Both techniques were used in combination with a Time-of-Flight path for the identification of the stable neighboring isotopes 92Zr and 94Zr. The passive absorber was represented by a stack of silicon nitride foils for high flexibility regarding the thickness for optimal isobar separation. Ion beams with a large variety of energies, between 80 and 180 MeV, were provided for this experiment by the tandem accelerator at the Maier-Leibnitz Laboratory in Garching, Germany. With these beams, the stopping powers of 93Zr and 93Nb as a function of energy were determined experimentally and compared to the results obtained with the simulation program SRIM. Considerable discrepancies regarding the energy dependence of the two stopping power curves relative to each other were found. The lowest detection limit for 93Zr achieved with the passive absorber setup was 93Zr/Zr = 1 · 10-10. In comparison, by optimizing the gas-filled magnet set-up, 93Nb was suppressed by around six orders of magnitude and a detection limit of 93Zr/Zr = 5 · 10-11 was obtained. To our knowledge, these results represent the lowest detection limit achieved for 93Zr until now.

  8. New results in low-energy fusion of 40Ca+Zr,9290

    Stefanini, A. M.; Montagnoli, G.; Esbensen, H.; Čolović, P.; Corradi, L.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Soić, N.; Strano, E.; Szilner, S.

    2017-07-01

    Background: Near- and sub-barrier fusion of various Ca + Zr isotopic combinations have been widely investigated. A recent analysis of 40Ca+96Zr data has highlighted the importance of couplings to multiphonon excitations and to both neutron and proton transfer channels. Analogous studies of 40Ca+90Zr tend to exclude any role of transfer couplings. However, the lowest measured cross section for this system is rather high (840 μ b ). A rather complete data set is available for 40Ca+94Zr , while no measurement of 40Ca+92Zr fusion has been performed in the past. Purpose: Our aim is to measure the full excitation function of 40Ca+92Zr near the barrier and to extend downward the existing data on 40Ca+90Zr , in order to estimate the transfer couplings that should be used in coupled-channels calculations of the fusion of these two systems and of 40Ca+94Zr . Methods: 40Ca beams from the XTU Tandem accelerator of INFN-Laboratori Nazionali di Legnaro were used, bombarding thin metallic 90Zr (50 μ g /cm2 ) and 92ZrO2 targets (same thickness) enriched to 99.36 % and 98.06 % in masses 90 and 92, respectively. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ER) at very forward angles, and angular distributions of ER were measured. Results: The excitation function of 40Ca+92Zr has been measured down to the level of ≃60 μ b . Coupled-channels (CC) calculations using a standard Woods-Saxon (WS) potential and following the line of a previous analysis of 40Ca+96Zr fusion data give a good account of the new data, as well as of the existing data for 40Ca+94Zr . The previous excitation function of 40Ca+90Zr has been extended down to 40 μ b . Conclusions: Transfer couplings play an important role in explaining the fusion data for 40Ca+92Zr and 40Ca+94Zr . The strength of the pair-transfer coupling is deduced by applying a simple recipe based on the value obtained for 40Ca+96Zr . The logarithmic slopes and the S factors for fusion are reproduced

  9. Fast optical signal not detected in awake behaving monkeys.

    Radhakrishnan, Harsha; Vanduffel, Wim; Deng, Hong Ping; Ekstrom, Leeland; Boas, David A; Franceschini, Maria Angela

    2009-04-01

    While the ability of near-infrared spectroscopy (NIRS) to measure cerebral hemodynamic evoked responses (slow optical signal) is well established, its ability to measure non-invasively the 'fast optical signal' is still controversial. Here, we aim to determine the feasibility of performing NIRS measurements of the 'fast optical signal' or Event-Related Optical Signals (EROS) under optimal experimental conditions in awake behaving macaque monkeys. These monkeys were implanted with a 'recording well' to expose the dura above the primary visual cortex (V1). A custom-made optical probe was inserted and fixed into the well. The close proximity of the probe to the brain maximized the sensitivity to changes in optical properties in the cortex. Motion artifacts were minimized by physical restraint of the head. Full-field contrast-reversing checkerboard stimuli were presented to monkeys trained to perform a visual fixation task. In separate sessions, two NIRS systems (CW4 and ISS FD oximeter), which previously showed the ability to measure the fast signal in human, were used. In some sessions EEG was acquired simultaneously with the optical signal. The increased sensitivity to cortical optical changes with our experimental setup was quantified with 3D Monte Carlo simulations on a segmented MRI monkey head. Averages of thousands of stimuli in the same animal, or grand averages across the two animals and across repeated sessions, did not lead to detection of the fast optical signal using either amplitude or phase of the optical signal. Hemodynamic responses and visual evoked potentials were instead always detected with single trials or averages of a few stimuli. Based on these negative results, despite the optimal experimental conditions, we doubt the usefulness of non-invasive fast optical signal measurements with NIRS.

  10. Internal oxidation of laminated ternary Ru–Ta–Zr coatings

    Chen, Yung-I, E-mail: yichen@mail.ntou.edu.tw; Lu, Tso-Shen

    2015-10-30

    Highlights: • Internal oxidation was observed in annealed and laminated Ru–Ta–Zr coatings. • The oxidized Ru–Ta–Zr coatings comprised three alternately stacked sublayers. • Correlated variations of O{sup 2-} and Zr{sup 4+} binding energies were verified in XPS spectra. - Abstract: Researchers have observed the internal oxidation phenomenon in binary alloy coatings when developing refractory alloy coatings for protective purposes by conducting annealing at high temperatures and in oxygen-containing atmospheres. The coatings were assembled using cyclical gradient concentration deposition during cosputtering by employing a substrate holder rotating at a slow speed. The internally oxidized zone demonstrated a laminated structure, comprising alternating oxygen-rich and oxygen-deficient layers stacked in a general orientation. In the current study, Ru–Ta–Zr coatings were prepared with various stacking sequences during cosputtering. The Ru–Ta–Zr coatings were annealed at 600 °C in an atmosphere continuously purged with 1% O{sub 2}–99% Ar mixed gas for 30 min. A transmission electron microscope was used to examine the periods of the laminated layers and crystallinity of the annealed coatings. Depth profiles produced using an Auger electron spectroscope and X-ray photoelectron spectroscope were used to certify the periodic variation of the related constituents and chemical states of the elements, respectively. The results indicate that the internally oxidized ternary coatings are stacked of Ru-, Ta{sub 2}O{sub 5}-, and ZrO{sub 2}-dominant sublayers and that the stacking sequences of the sublayers affect the crystalline structure of the coatings. Zr is oxidized preferentially in the Ru–Ta–Zr coatings, increasing the surface hardness of the oxidized coatings.

  11. Corrosion Behaviour of New Zr Alloys

    Tolksdorf, E.

    1974-01-01

    Corrosion studies have indicated that the most promising replacements for Zicaloy-2 are ZrCrFe, ZrVFe and probably ZrNbTa, provided they are in their optimized condition. These alloys are conventionally manufactured alloys. An internally oxidized ZrMgO alloy is even superior, from the corrosion...

  12. An Image Enhancement Method Using the Quantum-Behaved Particle Swarm Optimization with an Adaptive Strategy

    Xiaoping Su

    2013-01-01

    Full Text Available Image enhancement techniques are very important to image processing, which are used to improve image quality or extract the fine details in degraded images. In this paper, two novel objective functions based on the normalized incomplete Beta transform function are proposed to evaluate the effectiveness of grayscale image enhancement and color image enhancement, respectively. Using these objective functions, the parameters of transform functions are estimated by the quantum-behaved particle swarm optimization (QPSO. We also propose an improved QPSO with an adaptive parameter control strategy. The QPSO and the AQPSO algorithms, along with genetic algorithm (GA and particle swarm optimization (PSO, are tested on several benchmark grayscale and color images. The results show that the QPSO and AQPSO perform better than GA and PSO for the enhancement of these images, and the AQPSO has some advantages over QPSO due to its adaptive parameter control strategy.

  13. The elastic and thermodynamic properties of ZrMo2 from first principles calculations

    Liu, Xian-Kun; Zhou, Wei; Zheng, Zhou; Peng, Shu-Ming

    2014-01-01

    Highlights: • Elastic and thermodynamic properties of ZrMo 2 under high temperature and pressure are calculated by first principles. • Mechanical stability is testified from elastic constants at zero pressure. • Phonon scattering of ZrMo 2 under different temperature are obtained. - Abstract: The elastic and thermodynamic properties of ZrMo 2 under high temperature and pressure are investigated by first-principles calculations based on pseudopotential plane-wave density functional theory (DFT) within the generalized gradient approximation (GGA) and quasi-harmonic Debye model. The calculated lattice parameters are in good agreement with the available experimental data. The calculated elastic constants of ZrMo 2 increase monotonically with increasing pressure, and the relationship between the elastic constants and pressure show that ZrMo 2 satisfies the mechanical stability criteria under applied pressure (0–65 GPa). The related mechanical properties such as bulk modulus (B), shear modulus (G), Young’s modulus (E), and Poisson’s ratio (v) are also studied for polycrystalline of ZrMo 2 . The calculated B/G value shows that ZrMo 2 behaves in a ductile manner, and higher pressure can significantly improve the ductility of ZrMo 2 . The pressure and temperature dependencies of the relative volume, the bulk modulus, the elastic constants, the heat capacity and the thermal expansion coefficient, as well as the Grüneisen parameters are obtained and discussed by the quasi-harmonic Debye model in the ranges of 0–1800 K and 0–65 GPa

  14. Quantum Behaved Particle Swarm Optimization Algorithm Based on Artificial Fish Swarm

    Yumin, Dong; Li, Zhao

    2014-01-01

    Quantum behaved particle swarm algorithm is a new intelligent optimization algorithm; the algorithm has less parameters and is easily implemented. In view of the existing quantum behaved particle swarm optimization algorithm for the premature convergence problem, put forward a quantum particle swarm optimization algorithm based on artificial fish swarm. The new algorithm based on quantum behaved particle swarm algorithm, introducing the swarm and following activities, meanwhile using the a...

  15. Synthesis, spectral, DFT modeling, cytotoxicity and microbial studies of novel Zr(IV), Ce(IV) and U(VI) piroxicam complexes

    El-Shwiniy, Walaa H.; Zordok, Wael A.

    2018-06-01

    The Zr(IV), Ce(IV) and U(VI) piroxicam anti-inflammatory drug complexes were prepared and characterized using elemental analyses, conductance, IR, UV-Vis, magnetic moment, IHNMR and thermal analysis. The ratio of metal: Pir is found to be 1:2 in all complexes estimated by using molar ratio method. The conductance data reveal that Zr(IV) and U(VI) chelates are non-electrolytes except Ce(IV) complex is electrolyte. Infrared spectroscopic confirm that the Pir behaves as a bidentate ligand co-ordinated to the metal ions via the oxygen and nitrogen atoms of ν(Cdbnd O)carbonyl and ν(Cdbnd N)pyridyl, respectively. The kinetic parameters of thermogravimetric and its differential, such as activation energy, entropy of activation, enthalpy of activation, and Gibbs free energy evaluated using Coats-Redfern and Horowitz-Metzger equations for Pir and complexes. The geometry of the piroxicam drug in the Free State differs significantly from that in the metal complex. In the time of metal ion-drug bond formation the drug switches-on from the closed structure (equilibrium geometry) to the open one. The antimicrobial tests were assessed towards some types of bacteria and fungi. The in vitro cell cytotoxicity of the complexes in comparison with Pir against colon carcinoma (HCT-116) cell line was measured. Optimized geometrical structure of piroxicam ligand by using DFT calculations.

  16. Influence of ZrO2 nanoparticles and thermal treatment on the properties of PMMA/ZrO2 hybrid coatings

    Reyes-Acosta, M.A.; Torres-Huerta, A.M.; Domínguez-Crespo, M.A.; Flores-Vela, A.I.; Dorantes-Rosales, H.J.; Ramírez-Meneses, E.

    2015-01-01

    Highlights: • PMMA/ZrO 2 nanocomposites were prepared by melt blending in a single screw extruder. • The nanoparticles of m-, t-ZrO 2 were successfully synthesized using sol–gel technique. • The prepared PMMA/ZrO 2 nanocomposites have better UV protection than pure PMMA. • The thermal stability of the PMMA increases with low amount of ZrO 2 nanoparticles. • PMMA/ZrO 2 nanocomposites show superior values of elastic modulus and hardness. - Abstract: In this work, ZrO 2 nanoparticles were synthesized by the sol–gel method, treated thermally at different temperatures (400, 600 and 800 °C), and added to a polymer matrix in two different weight percentages (0.5 and 1) by single screw extrusion in order to determine the influence of these parameters on the thermal stability and UV radiation resistance of PMMA/ZrO 2 composites. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), ultraviolet–visible spectroscopy (UV–Vis), thermogravimetric analysis (TGA) and nanoindentation techniques were used to evaluate the structural, morphological, optical, thermal and mechanical properties of as-prepared composites. The average crystallite sizes for ZrO 2 sintered at 600 and 800 °C were about 17 and 26 nm, respectively. It was found that the incorporation of a low percentage of ZrO 2 nanoparticles increased the thermal properties of PMMA as well as its hardness and elastic modulus. The degradation temperature at 10 wt.% loss of the PMMA/ZrO 2 (0.5 wt.%, 400 °C) nanocomposite was approximately 48 °C higher than that of pure PMMA. The absorption in the UV region was increased according to the ZrO 2 heat treatment temperature and amount added to the polymer matrix

  17. Synthesis and antimicrobial evaluation of nanostructures ZrO2:AG against staphylococcus aureus by hydrothermal method

    Nova, C.V.; Reis, K.H.; Galico, D.A.; Venturini, J.; Pontes, F.M.L.; Pinheiro, A.L. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil); Longo, E. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2016-07-01

    Nanostructures of zirconia (ZrO2) has shown great prominence in the area of advanced materials and shows excellent properties such as chemical stability, mechanical strength, electrical and optical properties. When certain metals are supported on the compound, such as Fe, Ag, Au and Al, a potentiation of some properties, such as bactericide and fungicide can occur. Thus, this work deals with the synthesis and characterization of ZrO2 and ZrO2:Ag (1% and 10 % of Ag) nanostructures and the study of the influence of the antimicrobial activity against Staphylococcus aureus. X-ray powder diffractograms of the zirconia and silver with zirconia shown the formation of well defined peaks of tetragonal zirconia in all the samples. Although the ZrO2:Ag (10 % of Ag) shown the characteristics peaks of cubic silver, these peaks do not appear in ZrO2:Ag (1 % of Ag) due to the small amount of silver in comparison with zirconium. The crystal size was estimated by the Scherrer equation and the calculated values for zirconia were 12.84, 12.27 and 12.61 nm for ZrO2, ZrO2 : Ag (1%) and ZrO2 : Ag (10%) respectively and the silver crystal size was 8,09 nm. Diffuse reflectance of the silver particles shown a broad plasmon band at 405 and 424 nm for the ZrO2 : Ag (1%) and ZrO2 : Ag (10%). Antimicrobial assay demonstrated that ZrO2 showed a bacteriostatic effect (61 %) and the inclusion of the silver in the ZrO2 matrix enhanced this effect to 65-72 %. Both particles with different silver content shown similar effect {[ZrO2:Ag 1%] = [ZrO2:Ag 10%]>[ZrO2]}.(author)

  18. Impact of the oxygen defects and the hydrogen concentration on the surface of tetragonal and monoclinic ZrO2 on the reduction rates of stearic acid on Ni/ZrO2.

    Foraita, Sebastian; Fulton, John L; Chase, Zizwe A; Vjunov, Aleksei; Xu, Pinghong; Baráth, Eszter; Camaioni, Donald M; Zhao, Chen; Lercher, Johannes A

    2015-02-02

    The role of the specific physicochemical properties of ZrO2 phases on Ni/ZrO2 has been explored with respect to the reduction of stearic acid. Conversion on pure m-ZrO2 is 1.3 times more active than on t-ZrO2 , whereas Ni/m-ZrO2 is three times more active than Ni/t-ZrO2 . Although the hydrodeoxygenation of stearic acid can be catalyzed solely by Ni, the synergistic interaction between Ni and the ZrO2 support causes the variations in the reaction rates. Adsorption of the carboxylic acid group on an oxygen vacancy of ZrO2 and the abstraction of the α-hydrogen atom with the elimination of the oxygen atom to produce a ketene is the key to enhance the overall rate. The hydrogenated intermediate 1-octadecanol is in turn decarbonylated to heptadecane with identical rates on all catalysts. Decarbonylation of 1-octadecanol is concluded to be limited by the competitive adsorption of reactants and intermediate. The substantially higher adsorption of propionic acid demonstrated by IR spectroscopy and the higher reactivity to O2 exchange reactions with the more active catalyst indicate that the higher concentration of active oxygen defects on m-ZrO2 compared to t-ZrO2 causes the higher activity of Ni/m-ZrO2 . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Valence electron structure and properties of the ZrO2

    2008-01-01

    To reveal the properties of ZrO2 at the atom and electron levels, the valence elec- tron structures of three ZrO2 phases were analyzed on the basis of the empirical electron theory of solids and molecules. The results showed that the hybridization levels of Zr and O atoms in the m-ZrO2 were the same as those in the t-ZrO2, while those in the c-ZrO2 rose markedly. The electron numbers and bond energies on the strongest covalent bonds in the m-ZrO2 phase were the greatest, the values were 0.901106 and 157.5933 kJ/mol, respectively. Those in the t-ZrO2 phase took second place, which were 0.722182 and 123.9304 kJ/mol, and those in the c-ZrO2 phase were the smallest, which were 0.469323 and 79.0289 kJ/mol. According to the product of the bond energy on the strongest covalent bond and equivalent bond number (this value reflected the crystal cohesive energy), the order from the greatness to smallness was the c-ZrO2> t-ZrO2 > m-ZrO2. This showed that the m-phase bonds were the tightest, their energy was the smallest, the crystal cohe- sive energy of the m-phase was the largest, and the m-phase existed most stably at room temperature. So it must need energy or higher temperature to take apart the stronger covalent bonds to form a new phase.

  20. Valence electron structure and properties of the ZrO2

    LI JinPing; MENG SongHe; HAN JieCai; ZHANG XingHong

    2008-01-01

    To reveal the properties of ZrO2 at the atom and electron levels, the valence elec-tron structures of three ZrO2 phases were analyzed on the basis of the empirical electron theory of solids and molecules. The results showed that the hybridization levels of Zr and O atoms in the m-ZrO2 were the same as those in the t-ZrO2, while those in the c-ZrO2 rose markedly. The electron numbers and bond energies on the strongest covalent bonds in the m-ZrO2 phase were the greatest, the values were 0.901106 and 157.5933 kJ/mol, respectively. Those in the t-ZrO2 phase took second place, which were 0.722182 and 123.9304 kJ/mol, and those in the c-ZrO2 phase were the smallest, which were 0.469323 and 79.0289 kJ/mol. According to the product of the bond energy on the strongest covalent bond and equivalent bond number (this value reflected the crystal cohesive energy), the order from the greatness to smallness was the c-ZrO2 t-ZrO2 m-ZrO2. This showed that the m-phase bonds were the tightest, their energy was the smallest, the crystal cohe-sive energy of the m-phase was the largest, and the m-phase existed most stably at room temperature. So it must need energy or higher temperature to take apart the stronger covalent bonds to form a new phase.

  1. Stability and electronic structure of Zr-based ternary metallic glasses and relevant compounds

    Hasegawa, M.; Soda, K.; Sato, H.; Suzuki, T.; Taketomi, T.; Takeuchi, T.; Kato, H.; Mizutani, U.

    2007-01-01

    The electronic structure of the Zr-based metallic glasses has been investigated by theoretical and experimental approaches. One approach is band calculations of the Zr 2 Ni (Zr 66.7 Ni 33.3 ) compound to investigate the electronic structure of the Zr 66.7 Ni 33.3 metallic glass (ΔT x = 0 K) of which the local atomic structure is similar to that of the Zr 2 Ni compound. The other is photoemission spectroscopy of the Zr 50 Cu 35 Al 15 bulk metallic glass (BMG) (ΔT x = 69 K). Here ΔT x = T x - T g where T x and T g are crystallization and glass transition temperature, respectively. Both results and previous ones on the Zr 55 Cu 30 Ni 5 Al 10 BMG indicate that there is a pseudogap at the Fermi level in the electronic structure of these Zr-based metallic glasses, independent of the value of the ΔT x . This implies that the pseudogap at the Fermi level is one of the factors that stabilize the glass phase of Zr-based metallic glasses

  2. Elastic and transport properties of topological semimetal ZrTe

    Guo, San-Dong; Wang, Yue-Hua; Lu, Wan-Li

    2017-11-01

    Topological semimetals may have substantial applications in electronics, spintronics, and quantum computation. Recently, ZrTe was predicted as a new type of topological semimetal due to the coexistence of Weyl fermions and massless triply degenerate nodal points. In this work, the elastic and transport properties of ZrTe are investigated by combining the first-principles calculations and semiclassical Boltzmann transport theory. Calculated elastic constants prove the mechanical stability of ZrTe, and the bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio also are calculated. It is found that spin-orbit coupling (SOC) has slightly enhanced effects on the Seebeck coefficient, which along the a(b) and c directions for pristine ZrTe at 300 K is 46.26 μVK-1 and 80.20 μVK-1, respectively. By comparing the experimental electrical conductivity of ZrTe (300 K) with the calculated value, the scattering time is determined as 1.59 × 10-14 s. The predicted room-temperature electronic thermal conductivity along the a(b) and c directions is 2.37 {{Wm}}-1{{{K}}}-1 and 2.90 {{Wm}}-1{{{K}}}-1, respectively. The room-temperature lattice thermal conductivity is predicted as 17.56 {{Wm}}-1{{{K}}}-1 and 43.08 {{Wm}}-1{{{K}}}-1 along the a(b) and c directions, showing very strong anisotropy. Calculated results show that isotope scattering produces an observable effect on lattice thermal conductivity. To observably reduce lattice thermal conductivity by nanostructures, the characteristic length should be smaller than 70 nm, based on cumulative lattice thermal conductivity with respect to the phonon mean free path (MFP) at 300 K. It is noted that the average room-temperature lattice thermal conductivity of ZrTe is slightly higher than that of isostructural MoP, which is due to larger phonon lifetimes and smaller Grüneisen parameters. Finally, the total thermal conductivity as a function of temperature is predicted for pristine ZrTe. Our works provide valuable

  3. Zr/ZrC modified layer formed on AISI 440B stainless steel by plasma Zr-alloying

    Shen, H.H.; Liu, L.; Liu, X.Z.; Guo, Q.; Meng, T.X.; Wang, Z.X.; Yang, H.J.; Liu, X.P., E-mail: liuxiaoping@tyut.edu.cn

    2016-12-01

    Highlights: • A Zr/ZrC modified layer was formed on AISI 440B stainless steel using plasma surface Zr-alloying. • The thickness of the modified layer increases with alloying temperature and time. • Formation mechanism of the modified layer is dependent on the mutual diffusion of Zr and substrate elements. • The modified surface shows an improved wear resistance. - Abstract: The surface Zr/ZrC gradient alloying layer was prepared by double glow plasma surface alloying technique to increase the surface hardness and wear resistance of AISI 440B stainless steel. The microstructure of the Zr/ZrC alloying layer formed at different alloying temperatures and times as well as its formation mechanism were discussed by using scanning electron microscopy, glow discharge optical emission spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The adhesive strength, hardness and tribological property of the Zr/ZrC alloying layer were also evaluated in the paper. The alloying surface consists of the Zr-top layer and ZrC-subsurface layer which adheres strongly to the AISI 440B steel substrate. The thickness of the Zr/ZrC alloying layer increases gradually from 16 μm to 23 μm with alloying temperature elevated from 900 °C to 1000 °C. With alloying time from 0.5 h to 4 h, the alloyed depth increases from 3 μm to 30 μm, and the ZrC-rich alloyed thickness vs time is basically parabola at temperature of 1000 °C. Both the hardness and wear resistance of the Zr/ZrC alloying layer obviously increase compared with untreated AISI 440B steel.

  4. Zr/ZrC modified layer formed on AISI 440B stainless steel by plasma Zr-alloying

    Shen, H. H.; Liu, L.; Liu, X. Z.; Guo, Q.; Meng, T. X.; Wang, Z. X.; Yang, H. J.; Liu, X. P.

    2016-12-01

    The surface Zr/ZrC gradient alloying layer was prepared by double glow plasma surface alloying technique to increase the surface hardness and wear resistance of AISI 440B stainless steel. The microstructure of the Zr/ZrC alloying layer formed at different alloying temperatures and times as well as its formation mechanism were discussed by using scanning electron microscopy, glow discharge optical emission spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The adhesive strength, hardness and tribological property of the Zr/ZrC alloying layer were also evaluated in the paper. The alloying surface consists of the Zr-top layer and ZrC-subsurface layer which adheres strongly to the AISI 440B steel substrate. The thickness of the Zr/ZrC alloying layer increases gradually from 16 μm to 23 μm with alloying temperature elevated from 900 °C to 1000 °C. With alloying time from 0.5 h to 4 h, the alloyed depth increases from 3 μm to 30 μm, and the ZrC-rich alloyed thickness vs time is basically parabola at temperature of 1000 °C. Both the hardness and wear resistance of the Zr/ZrC alloying layer obviously increase compared with untreated AISI 440B steel.

  5. Structural, electrical and optical properties of nanostructured ZrO2 thin film deposited by SILAR method

    Salodkar, R. V.; Belkhedkar, M. R.; Nemade, S. D.

    2018-05-01

    Successive Ionic Layer Adsorption and Reaction (SILAR) method has been employed to deposit nanocrystalline ZrO2 thin film of thickness 91 nm onto glass substrates using ZrOCl2.8H2O and NaOH as cationic and anionic precursors respectively. The structural and surface morphological characterizations have been carried out by means of X-ray diffraction and field emission scanning electron microscopy confirms the nanocrystalline nature of ZrO2 thin film. The direct optical band gap and activation energy of the ZrO2 thin film are found to be 4.74 and 0.80eV respectively.

  6. Numerical investigation for one bad-behaved flow in a Pelton turbine

    Wei, X Z; Yang, K; Wang, H J; Gong, R Z; Li, D Y

    2015-01-01

    The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper

  7. Numerical investigation for one bad-behaved flow in a Pelton turbine

    Wei, X. Z.; Yang, K.; Wang, H. J.; Gong, R. Z.; Li, D. Y.

    2015-01-01

    The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper.

  8. Microstructural characterization and tribological behavior of surface plasma Zr-Er alloying on TC11 alloy

    Wei, Dongbo; Zhang, Pingze; Liu, Yingchao; Chen, Xiaohu; Ding, Feng; Li, Fengkun

    2018-02-01

    The Zr coating and Zr-Er coating are grown on TC11 substrate by double-glow plasma surface metallurgy technique, followed by the wear tests at ambient temperature and 500 °C. The data of nanohardness and elastic modulus of the samples are collected by the nano-indentation test. The adhesion strength of coatings is investigated by means of the scratch test. The study of wear resistance is performed using a ball-on-disc wear test system by running against the Si3N4 ball and measured by scanning electron microscope (SEM) and X-ray diffraction (XRD). Experimental results indicate that the nanohardness of the Zr coating and Zr-Er coating are 5.94 GPa and 7.98 GPa, respectively, which are 1.79 times and 2.41 times greater than that of TC11 substrate. Zr coating and Zr-Er coating realize the metallurgical bonding with TC11 substrate with continuous and compact structure. Compared with the Zr coating and TC11, the Zr-Er coating presents the lowest specific wear rates, which are 1.689 × 10-6 mm3 Nm-1 and 1.851 × 10-6 mm3 Nm-1 at ambient temperature and 500 °C respectively, indicating the excellent and improved wear resistance of TC11.

  9. Physical properties of Zr50Cu40-xAl10Pdx bulk glassy alloys

    Wencka, M.; Jagodic, M.; Gradisek, A.; Kocjan, A.; Jaglicic, Z.; McGuiness, P.J.; Apih, T.; Yokoyama, Y.; Dolinsek, J.

    2010-01-01

    It was shown recently (Yokoyama et al. ) that the addition of a small amount of Pd to the Zr 50 Cu 40 Al 10 bulk glassy alloy (BGA) has a beneficial effect on fatigue-strength enhancement, where the composition Zr 50 Cu 37 Al 10 Pd 3 behaved in a resonant-like way by showing the highest fatigue limit of 1050 MPa and the minimum Vickers hardness. We performed a study of the magnetic properties, the specific heat, the electrical resistivity and the hydrogen-diffusion constant for a series of compositions Zr 50 Cu 40-x Al 10 Pd x (x = 0-7 at.%), in order to determine their physical properties and to check for the influence of the Pd content on these properties. The Zr 50 Cu 40-x Al 10 Pd x BGAs are nonmagnetic, conducting alloys, where the Pauli spin susceptibility of the conduction electrons is the only source of paramagnetism. The low-temperature specific heat indicates an enhancement of the conduction-electron effective mass m* below 5 K, suggesting that the Zr 50 Cu 40-x Al 10 Pd x BGAs are not free-electron-like compounds. The electrical resistivities of the Zr 50 Cu 40-x Al 10 Pd x BGAs amount to about 200 μΩ cm and show a small, negative temperature coefficient (NTC) with an increase from 300 to 2 K of 4%. The hydrogen self-diffusion constant D in hydrogen-loaded samples shows classical over-barrier-hopping temperature dependence and is of comparable magnitude to the related icosahedral and amorphous Zr 69.5 Cu 12 Ni 11 Al 7.5 hydrogen-storage alloys. No correlation between the investigated physical parameters and the Pd content of the samples could be observed.

  10. The {sup 95}Zr( n , γ ){sup 96}Zr Cross Section from the Surrogate Ratio Method and Its Effect on s -process Nucleosynthesis

    Yan, S.Q.; Li, Z.H.; Wang, Y.B.; Su, J.; Li, Y. J.; Han, Y.L.; Shen, Y.P.; Guo, B.; Zeng, S.; Lian, G.; Chen, Y.S.; Liu, W.P. [China Institute of Atomic Energy, P.O. Box 275(10), Beijing 102413 (China); Nishio, K.; Makii, H.; Nishinaka, I.; Hirose, K.; Orlandi, R. [Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Lugaro, M. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121 Budapest (Hungary); Karakas, A. I. [Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, Clayton, VIC 3800 (Australia); Mohr, P., E-mail: panyu@ciae.ac.cn, E-mail: maria.lugaro@csfk.mta.hu [Institute for Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary)

    2017-10-20

    The {sup 95}Zr( n , γ ){sup 96}Zr reaction cross section is crucial in the modeling of s -process nucleosynthesis in asymptotic giant branch stars because it controls the operation of the branching point at the unstable {sup 95}Zr and the subsequent production of {sup 96}Zr. We have carried out the measurement of the {sup 94}Zr({sup 18}O, {sup 16}O) and {sup 90}Zr({sup 18}O, {sup 16}O) reactions and obtained the γ -decay probability ratio of {sup 96}Zr* and {sup 92}Zr* to determine the {sup 95}Zr( n , γ ){sup 96}Zr reaction cross sections with the surrogate ratio method. Our deduced Maxwellian-averaged cross section of 66 ± 16 mb at 30 keV is close to the value recommended by Bao et al., but 30% and more than a factor of two larger than the values proposed by Toukan and Käppeler and Lugaro et al., respectively, and routinely used in s -process models. We tested the new rate in stellar models with masses between 2 and 6 M {sub ⊙} and metallicities of 0.014 and 0.03. The largest changes—up to 80% variations in {sup 96}Zr—are seen in models of mass 3–4 M {sub ⊙}, where the {sup 22}Ne neutron source is mildly activated. The new rate can still provide a match to data from meteoritic stardust silicon carbide grains, provided that the maximum mass of the parent stars is below 4 M {sub ⊙}, for a metallicity of 0.03.

  11. Interdiffusion between U-Zr-Mo and stainless steel cladding

    Hwang, J. Y.; Lee, B. S.; Lee, J. T.; Kang, Y. H.

    1998-01-01

    Interdiffusion investigations were carried out at 700 deg C for 200 hours for the diffusion couples assembled with the U-Zr-Mo ternary fuel versus austenitic stainless steel D9 and the U-Zr-Mo ternary fuel versus martensitic stainless steel HT9 respectively to investigate the fuel-cladding compatibility. SEM-EDS analysis was utilized to determine the composition and the penetration depths of the reaction layers. In the case of Fuel/D9 couple, (Fe, Cr, Ni) of the cladding elements formed the precipitates with the Zr, Mo and diminished the U concentration upto 800μ length from the fuel side. Composition of the precipitates was varied with the penetrated elements. In Fuel/HT9 couple, reaction layer was smaller than that of D9 couples and was less affected by cladding elements. The eutectic reaction appeared partially in the Fuel/HT9 diffusion couple

  12. Comparison of results analysis of chemical composition of alloys inside the U-Zr-Nb by XRF and AAS techniques

    Masrukan; Tri Yulianto; Anwar Muchsin

    2011-01-01

    U-Zr-Nb alloy chemical composition analysis using X Ray Fluorescence (XRF) and Atomic Absorption Spectroscopy (AAS) techniques have been conducted, where U-Zr- Nb alloy was chosen as candidates for new high-density fuel for future research reactors . Composition analysis is necessary because the composition of elements in the fuel will determine the characteristics of fuel during the fabrication process and in the reactor. The use of two kinds of analysis techniques were designed to obtain accurate analysis results. The experiment was conducted to determine the major element composition and impurities in the alloy U-Zr-Nb. First U-Zr-Nb varying alloy composition Nb were respectively 1%, 4%, 7% (U10% Zr1% Nb, U10% Zr4% Nb and U10% 7% Nb) as results of the melting process of measuring the diameter of 120 mm crushed on the surface bottom. Once on the bottom surface is smooth, then analyzed using XRF techniques. To analyze the elements using AAS techniques, alloy U-Zr-Nb cut into 10 mm x 5 mm then dissolved using HF and nitric acid. Solution that occurred were analyzed using AAS technique. From the analysis using the XRF technique is obtained the alloy U-10% Zr-1% Nb, U-10% Zr-4% Nb and Zr-10% U-7% Nb) had a content of each element as follows: U (87.8858%), Zr (2.6097%) and Nb (0.2206%), U (87.8556%), Zr (2.6302%), and Nb (0.6573%); U (84.6334%), Zr (2.5773%), and Nb (1.0940) weight. Results of analysis using AAS techniques on samples obtained third consecutive Zr content of 9.25%, 8.90% and 9.80% while the content of Nb was not detected. Meanwhile, the results of elemental analysis of impurities in all three samples showed that almost all the elements are still qualify as fuel except Zn element. Element Zn at the three samples of each alloys U-10% Zr-1% Nb, U-10% Zr-4% Nb and U-10% Zr-7%Nb is 1.3266%, 3.2756% and 1.0927% weight. It could be concluded that the results of analysis of elemental content and impurities in the alloy U-Nb-Zr using both XRF and AAS visible

  13. The secondary electron yield of TiZr and TiZrV non evaporable getter thin film coatings

    Scheuerlein, C; Hilleret, Noël; Taborelli, M

    2001-01-01

    The secondary electron yield (SEY) of two different non evaporable getter (NEG) samples has been measured 'as received' and after thermal treatment. The investigated NEGs are TiZr and TiZrV thin film coatings of 1 mm thickness, which are sputter deposited onto copper substrates. The maximum SEY dmax of the air exposed TiZr and TiZrV coating decreases from above 2.0 to below 1.1 during a 2 hour heat treatment at 250 °C and 200 °C, respectively. Saturating an activated TiZrV surface under vacuum with the gases typically present in ultra high vacuum systems increases dmax by about 0.1. Changes in elemental surface composition during the applied heat treatments were monitored by Auger electron spectroscopy (AES). After activation carbon, oxygen and chlorine were detected on the NEG surfaces. The potential of AES for detecting the surface modifications which cause the reduction of SE emission during the applied heat treatments is critically discussed.

  14. Shape memory characteristics of Ti-22Nb-(2-8)Zr(at.%) biomedical alloys

    Kim, J.I.; Kim, H.Y.; Inamura, T.; Hosoda, H.; Miyazaki, S.

    2005-01-01

    Shape memory characteristics of Ti-22Nb-(2-8)Zr(at.%) biomedical alloys were investigated by using tensile tests and X-ray diffraction (XRD) measurement. The alloy ingots were fabricated by an arc melting method. The ingots were cold-rolled by a reduction up to 95% in thickness at room temperature. All the alloys were solution-treated at 1173 K for 1.8 ks. The alloys subjected to the solution treatment exhibited large elongations ranging between 28 and 40%. The martensitic transformation temperature decreased by 38 K with 1 at.% increase of Zr content. The maximum recovered strain of 4.3% was obtained in the Ti-22Nb-4Zr(at.%) alloy. Ti-22Nb-(2-4)Zr(at.%) and Ti-22Nb-6Zr(at.%) alloys exhibited stable shape memory effect and superelastic behavior at room temperature, respectively

  15. Bracketed morality revisited: how do athletes behave in two contexts?

    Kavussanu, Maria; Boardley, Ian D; Sagar, Sam S; Ring, Christopher

    2013-10-01

    The concept of bracketed morality has received empirical support in several sport studies (e.g., Bredemeier & Shields, 1986a, 1986b). However, these studies have focused on moral reasoning. In this research, we examined bracketed morality with respect to moral behavior in sport and university contexts, in two studies. Male and female participants (Study 1: N = 331; Study 2: N = 372) completed questionnaires assessing prosocial and antisocial behavior toward teammates and opponents in sport and toward other students at university. Study 2 participants also completed measures of moral disengagement and goal orientation in both contexts. In most cases, behavior in sport was highly correlated with behavior at university. In addition, participants reported higher prosocial behavior toward teammates and higher antisocial behavior toward opponents in sport than toward other students at university. The effects of context on antisocial behavior were partially mediated by moral disengagement and ego orientation. Our findings extend the bracketed morality concept to prosocial and antisocial behavior.

  16. Low-temperature synthesis of ZrB2 powder from oxides using Na

    Haruhiko Morito

    2017-12-01

    Full Text Available ZrB2 was synthesized by heating a mixture of ZrO2, B2O3, and Na in a molar ratio of 1:1:5 at 873–1273 K. While unreacted ZrO2 remained in the sample synthesized at 873 K, single phase ZrB2 powders were obtained at temperatures ≥1073 K. The diameters of the ZrB2 particles obtained at 1073 and 1273 K were 0.1–20 and 10–100 μm, respectively. Single phase ZrB2 was also obtained at 873 K when the starting material was rich in B2O3 and Na (ZrO2:B2O3:Na = 1:5:15. This route yielded fine particle aggregates of ZrB2, which were found to be <0.1 μm in size.

  17. Microstructural Improvement of Hydroxyapatite-ZrO2 Composite Ceramics via Thermal Precipitation Techniques.

    Sangmala, A.; Limsuwan, P.; Kaewwiset, W.; Naemchanthara, K.

    2017-09-01

    Hydroxyapatite-ZrO2 composite ceramic were synthesized using a thermal precipitation techniques. The chemical precursors were prepared from di-ammonium hydrogen orthophosphate, calcium oxide (CaO) derived from chicken eggshell, zirconium dioxide (ZrO2) and distilled water. The mixture were heated at the various temperatures from 100 to 700 °C in the furnace with an incremental temperature of 100 °C. The ZrO2 contents in the composite ceramic were varied from 0 to 15 percent weight of CaO. The prepared composites were then annealed at 300, 600 and 700 °C for 4 h in air. The crystal structure, function group and morphology of all samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and universal testing machine (UTM), respectively. The results indicated that the undoped-ZrO2 samples hydroxyapatite phase with a hexagonal structure. However, the hydroxyapatite was transformed to the tri-calcium phosphate after thermal treatment at 700 °C. For the doped-ZrO2 samples, the hydroxyapatite and ZrO2 phases were found. Moreover, the result showed that the compressive strength of hydroxyapatite-ZrO2 composite ceramic increased with increasing the ZrO2 content.

  18. Heat-capacity measurement on (Zr1-ySny)Ox from 325 to 905 K

    Tsuji, Toshihide; Amaya, Masaki; Naito, Keiji

    1993-01-01

    Heat capacities of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 (y=0-0.07) having α''-ZrO ∼1/6 and α''-ZrO x type crystal structures, respectively, were measured from 325 to 905 K by using an adiabatic scanning calorimeter. Two kinds of heat capacity anomalies were observed for all samples. The anomaly at lower temperatures is attributed to a nonequilibrium phenomenon. Another anomaly at higher temperatures is assigned to an order-disorder rearrangement of oxygen atoms. The transition temperature, transition enthalpy and entropy changes due to the order-disorder transition decreased with increasing tin content, indicating that arrangement of oxygen atoms in the lower temperature phase may be partially disordered by substituting tin for zirconium. The entropy change due to the order-disorder transition for (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 solid solutions is compared with the theoretical value. The solubility limits of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 were determined from the variation of lattice constants, transition temperature, transition enthalpy and entropy changes against tin content. (orig.)

  19. Atom probe tomographic studies of precipitation in Al-0.1Zr-0.1Ti (at.%) alloys.

    Knipling, Keith E; Dunand, David C; Seidman, David N

    2007-12-01

    Atom probe tomography was utilized to measure directly the chemical compositions of Al(3)(Zr(1)-(x)Ti(x)) precipitates with a metastable L1(2) structure formed in Al-0.1Zr-0.1Ti (at.%) alloys upon aging at 375 degrees C or 425 degrees C. The alloys exhibit an inhomogeneous distribution of Al(3)(Zr(1)-(x)Ti(x)) precipitates, as a result of a nonuniform dendritic distribution of solute atoms after casting. At these aging temperatures, the Zr:Ti atomic ratio in the precipitates is about 10 and 5, respectively, indicating that Ti remains mainly in solid solution rather than partitioning to the Al(3)(Zr(1)-(x)Ti(x)) precipitates. This is interpreted as being due to the very small diffusivity of Ti in alpha-Al, consistent with prior studies on Al-Sc-Ti and Al-Sc-Zr alloys, where the slower diffusing Zr and Ti atoms make up a small fraction of the Al(3)(Zr(1)-(x)Ti(x)) precipitates. Unlike those alloys, however, the present Al-Zr-Ti alloys exhibit no interfacial segregation of Ti at the matrix/precipitate heterophase interface, a result that may be affected by a significant disparity in the evaporation fields of the alpha-Al matrix and Al(3)(Zr(1)-(x)Ti(x)) precipitates and/or a lack of local thermodynamic equilibrium at the interface.

  20. Fretting wear of ZrN and Zr(21% Hf)N coatings

    Atar, E. [Gebze Inst. of Tech., Material Science and Engineering Dept., Kocaeli (Turkey); Cimenoglu, H.; Kayali, E.S. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Engineering, Istanbul (Turkey)

    2004-07-01

    In this study, the wear behaviours of ZrN and Zr(21% Hf)N coatings, deposited on hardened AISI D2 cold work tool steel were examined by a fretting wear tester. The hardness of ZrN and Zr(21% Hf)N coatings were almost the same, where as they exhibited different wear resistance. Addition of 21% Hf to ZrN coating achieved about 25% increase in the wear resistance. (orig.)

  1. Fretting wear of ZrN and Zr(21% Hf)N coatings

    Atar, E.; Cimenoglu, H.; Kayali, E.S.

    2004-01-01

    In this study, the wear behaviours of ZrN and Zr(21% Hf)N coatings, deposited on hardened AISI D2 cold work tool steel were examined by a fretting wear tester. The hardness of ZrN and Zr(21% Hf)N coatings were almost the same, where as they exhibited different wear resistance. Addition of 21% Hf to ZrN coating achieved about 25% increase in the wear resistance. (orig.)

  2. Magnetic properties of FeZr{sub 2} and Fe{sub 2}Zr intermetallic compounds

    Prajapat, C. L., E-mail: prajapat@barc.gov.in; Singh, M. R.; Mishra, P. K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Chattaraj, D. [Product Development Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Mishra, R. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Ravikumar, G. [Scientific Information Resources Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India)

    2016-05-23

    Magnetic properties of Fe-Zr system, viz., FeZr{sub 2} and Fe{sub 2}Zr have been studied. Both the compounds show soft ferromagnetic behavior. Curie temperature is well above the room temperature. Lower saturation magnetization for the zirconium rich sample, FeZr{sub 2}, could be due to possible donation of electrons from the Zr-rich neighbors to Fe atoms or diminution of long range magnetic order by defects.

  3. Scientists Still Behaving Badly? A Survey Within Industry and Universities.

    Godecharle, Simon; Fieuws, Steffen; Nemery, Ben; Dierickx, Kris

    2017-10-02

    Little is known about research misconduct within industry and how it compares to universities, even though a lot of biomedical research is performed by-or in collaboration with-commercial entities. Therefore, we sent an e-mail invitation to participate in an anonymous computer-based survey to all university researchers having received a biomedical research grant or scholarship from one of the two national academic research funders of Belgium between 2010 and 2014, and to researchers working in large biomedical companies or spin-offs in Belgium. The validated survey included questions about various types of research misconduct committed by respondents themselves and observed among their colleagues in the last three years. Prevalences of misconduct were compared between university and industry respondents using binary logistic regression models, with adjustments for relevant personal characteristics, and with significance being accepted for p industry. Response rates were 43 (767/1766) and 48% (123/255), and usable information was available for 617 and 100 respondents, respectively. In general, research misconduct was less likely to be reported by industry respondents compared to university respondents. Significant differences were apparent for one admitted action (gift authorship) and three observed actions (plagiarism, gift authorship, and circumventing animal-subjects research requirements), always with lower prevalences for industry compared to universities, except for plagiarism. This survey, based on anonymous self-report, shows that research misconduct occurs to a substantial degree among biomedical researchers from both industry and universities.

  4. Effect of SiO 2-ZrO 2 supports prepared by a grafting method on hydrogen production by steam reforming of liquefied natural gas over Ni/SiO 2-ZrO 2 catalysts

    Seo, Jeong Gil; Youn, Min Hye; Song, In Kyu

    SiO 2-ZrO 2 supports with various zirconium contents are prepared by grafting a zirconium precursor onto the surface of commercial Carbosil silica. Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are then prepared by an impregnation method, and are applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of SiO 2-ZrO 2 supports on the performance of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts is investigated. SiO 2-ZrO 2 prepared by a grafting method serves as an efficient support for the nickel catalyst in the steam reforming of LNG. Zirconia enhances the resistance of silica to steam significantly and increases the interaction between nickel and the support, and furthermore, prevents the growth of nickel oxide species during the calcination process through the formation of a ZrO 2-SiO 2 composite structure. The crystalline structures and catalytic activities of the Ni(20 wt.%)/SiO 2-ZrO 2 catalysts are strongly influenced by the amount of zirconium grafted. The conversion of LNG and the yield of hydrogen show volcano-shaped curves with respect to zirconium content. Among the catalysts tested, the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) sample shows the best catalytic performance in terms of both LNG conversion and hydrogen yield. The well-developed and pure tetragonal phase of ZrO 2-SiO 2 (Zr/Si = 0.54) appears to play an important role in the adsorption of steam and subsequent spillover of steam from the support to the active nickel. The small particle size of the metallic nickel in the Ni(20 wt.%)/SiO 2-ZrO 2 (Zr/Si = 0.54) catalyst is also responsible for its high performance.

  5. Preferential Creation of Polar Translational Boundaries by Interface Engineering in Antiferroelectric PbZrO3 Thin Films

    Wei XK; Vaideeswaran K; Sandu CS; Jia CL; Setter N

    2015-01-01

    Polar translational boundaries (PTBs) are preferentially created in antiferroelectric PbZrO3 films through interfacial engineering. Probe corrected scanning transmission electron microscopy studies reveal that RIII 1 and RI 1 type PTBs are favorably created in PbZrO3/BaZrO3/SrTiO3 and PbZrO3/SrTiO3 films respectively. The relationship between interfacial strain and the internal strain of boundaries is the driving force for the selective formation of PTBs.

  6. Improved quantum-behaved particle swarm optimization with local search strategy

    Maolong Xi

    2017-03-01

    Full Text Available Quantum-behaved particle swarm optimization, which was motivated by analysis of particle swarm optimization and quantum system, has shown compared performance in finding the optimal solutions for many optimization problems to other evolutionary algorithms. To address the problem of premature, a local search strategy is proposed to improve the performance of quantum-behaved particle swarm optimization. In proposed local search strategy, a super particle is presented which is a collection body of randomly selected particles’ dimension information in the swarm. The selected probability of particles in swarm is different and determined by their fitness values. To minimization problems, the fitness value of one particle is smaller; the selected probability is more and will contribute more information in constructing the super particle. In addition, in order to investigate the influence on algorithm performance with different local search space, four methods of computing the local search radius are applied in local search strategy and propose four variants of local search quantum-behaved particle swarm optimization. Empirical studies on a suite of well-known benchmark functions are undertaken in order to make an overall performance comparison among the proposed methods and other quantum-behaved particle swarm optimization. The simulation results show that the proposed quantum-behaved particle swarm optimization variants have better advantages over the original quantum-behaved particle swarm optimization.

  7. Structural study of Zr-based metallic glasses

    Matsubara, E.; Ichitsubo, T.; Saida, J.; Kohara, S.; Ohsumi, H.

    2007-01-01

    Structures of Zr 70 Ni 20 Al 10 , Zr 70 Cu 20 Al 10 , Zr 70 Cu 30 and Zr 70 Ni 30 amorphous alloys were analyzed by high-energy X-ray diffraction. The relatively stable Zr 2 Cu amorphous alloy shows a local atom arrangement different from the Zr 2 Cu crystalline phase. By contrast, the less stable Zr 70 Ni 30 amorphous alloy has a structure similar to Zr 2 Ni. In the Zr 70 Cu 20 Al 10 metallic glass, Zr-Al nearest neighbor pairs are introduced in the amorphous structure. In the Zr 70 Ni 20 Al 10 metallic glass, the strong correlation between Zr-Ni pairs is drastically modified by the formation of Zr-Al pairs. The presence of Zr-Al pairs in the ternary alloys suppresses the crystallization and stabilizes the glassy state

  8. [Dynamics of 95Zr in simulated marine water-sediment-organisms system].

    Wang, Chunlin; Shi, Jianjun; Sun, Pingyue; Li, Mingyun

    2003-06-01

    To provide scientific evidence to evaluate the behavior of 95Zr in ocean ecosystem, the dynamic model of the transference, accumulation and disappearance of 95Zr among the simulated marine water, sediment and organisms was investigated using Nassarius semiplicatus and Boleophthalums pectinirostris as experimental stuffs. The result showed that 95Zr(Bq.g-1 or Bq.ml-1) in the marine water was decreased more than 90% in the first 4 h, and then descended gradually. 95Zr in sediment was increased in the peak in 48 h and then declined. The radioactivity percent of 95Zr in the shell and muslce of Nassarius semiplicatus was 68.7% and 31.30% respectively, while the radioactivity percent was 22.80%, 12.64%, 34.82%, 10.31%, 4.48%, 11.55% and 3.71%, respectively in the fill, fin, viscera, skull, skin, vertebra and muscle of Boleophthalmus pectinirostris. Nassarius semiplicatus had a greater concentrating capability of 95Zr than Boleophthalmus pectinirostris. The order of the 95Zr concentration was found to be sediment > Nassarius semiplicatus > water > Boleophthalmus pectinirostris. A dynamic model of closed four-compartment was constructed with exponent function.

  9. Effect of structural defects on electronic and magnetic properties of ZrS2 monolayer

    Wang, Haiyang; Zhao, Xu; Gao, Yonghui; Wang, Tianxing; Wei, Shuyi

    2018-04-01

    We aimed at ten configurations of vacancy defects and used the first-principles methods based on density functional theory to research electronic and magnetic properties of ZrS2 monolayer. Results show that the system of two-zirconium vacancy (V2zr) and one Zr atom + one S atom vacancy (V1Zr+1S) can induce to total spin magnetic moment of 0.245μB and 0.196μB, respectively. In addition, three and six S atoms vacancy can induce corresponding system to manifest spin magnetic moment of 0.728μB and 3.311μB, respectively. In S atom vacancy defects, vacancy defects can transform the system from semiconductor to metal, several of the Zr atoms and adjacent S atoms display antiferromagnetism coupling in three apart S atom vacancy defects. Vacancy defects can make the intrisic monolayer ZrS2 transform semiconductor into metal. These results are important for the achievement of spin devices based on ZrS2 semiconductor.

  10. Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

    A. Schlechte, R. Niewa, M. Schmidt, G. Auffermann, Yu. Prots, W. Schnelle, D. Gnida, T. Cichorek, F. Steglich and R. Kniep

    2007-01-01

    Full Text Available Ternary phases in the systems Zr–As–Se and Zr–As–Te were studied using single crystals of ZrAs1.40(1Se0.50(1 and ZrAs1.60(2Te0.40(1 (PbFCl-type of structure, space group P4/nmm as well as ZrAs0.70(1Se1.30(1 and ZrAs0.75(1Te1.25(1 (NbPS-type of structure, space group Immm. The characterization covers chemical compositions, crystal structures, homogeneity ranges and electrical resistivities. At 1223 K, the Te-containing phases can be described with the general formula ZrAsxTe2−x, with 1.53(1≤x≤1.65(1 (As-rich and 0.58(1≤x≤0.75(1 (Te-rich. Both phases are located directly on the tie-line between ZrAs2 and ZrTe2, with no indication for any deviation. Similar is true for the Se-rich phase ZrAsxSe2−x with 0.70(1≤x≤0.75(1. However, the compositional range of the respective As-rich phase ZrAsx−ySe2−x (0.03(1≤y≤0.10(1; 1.42(1≤x≤1.70(1 is not located on the tie-line ZrAs2–ZrSe2, and exhibits a triangular region of existence with intrinsic deviation of the composition towards lower non-metal contents. Except for ZrAs0.75Se1.25, from the homogeneity range of the Se-rich phase, all compounds under investigation show metallic characteristics of electrical resistivity at temperatures >20 K. Related uranium and thorium arsenide selenides display a typical magnetic field-independent rise of the resistivity towards lower temperatures, which has been explained by a non-magnetic Kondo effect. However, a similar observation has been made for ZrAs1.40Se0.50, which, among the Zr-based arsenide chalcogenides, is the only system with a large concentration of intrinsic defects in the anionic substructure.

  11. Structural characterization and optical properties of perovskite ZnZrO 3 nanoparticles

    Zhu, Xinhua

    2014-03-17

    Perovskite ZnZrO3 nanoparticles were synthesized by hydrothermal method, and their microstructures and optical properties were characterized. The crystallinity, phase formation, morphology and composition of the as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), selected area electron diffraction (SAED), high-resolutiontransmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) spectroscopy analysis, respectively. TEM images demonstrated that the average particle size of the ZnZrO3 powders was increased with increasing the Zn/Zr molar ratios in the precursors, and more large ZnZrO3 particles with cubic morphology were observed at high Zn/Zr molar ratios. In addition, the phase structures of the ZnZrO3 particles were also evolved from a cubic to tetragonal perovskite phase, as revealed by XRD and SAED patterns. HRTEM images demonstrate that surface structures of the ZnZrO3 powders synthesized at high Zn/Zr molar ratios, are composed of corners bound by the {100} mini-facets, and the surface steps lying on the {100} planes are frequently observed, whereas the (101) facet isoccasionally observed. The formation of such a rough surface structure is understood from the periodic bond chain theory. Quantitative EDX analyses demonstrated that the atomic concentrations (at.%) of Zn:Zr:O in the particles were 20.70:21.07:58.23, as close to the composition of ZnZrO3. In the optical spectra, a significant red shift of the absorption edges (for the ZnZrO3 nanopowders) from UV to visible region (from 394 to 417 nm) was observed as increasing the Zn/Zr molar ratios in the precursors, which corresponds to that the band gap energies of the ZnZrO3 nanopowders can be continuously tuned from 3.15 to 2.97 eV. This opens an easy way to tune the band gap energies of the ZnZrO3 nanopowders. © 2014 The American Ceramic Society.

  12. Preparation and characterization of PbO2–ZrO2 nanocomposite electrodes

    Yao Yingwu; Zhao Chunmei; Zhu Jin

    2012-01-01

    PbO 2 –ZrO 2 nanocomposite electrodes were prepared by the anodic codeposition in the lead nitrate plating bath containing ZrO 2 nanoparticles. The influences of the ZrO 2 nanoparticles concentration, current density, temperature and stirring rate of the plating bath on the composition of the nanocomposite electrodes were investigated. The surface morphology and the structure of the nanocomposite electrodes were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. The experimental results show that the addition of ZrO 2 nanoparticles in the electrodeposition process of lead dioxide significantly increases the lifetime of nanocomposite electrodes. The PbO 2 –ZrO 2 nanocomposite electrodes have a service life of 141 h which is almost four times longer than that of the pure PbO 2 electrodes. The morphology of PbO 2 –ZrO 2 nanocomposite electrodes is more compact and finer than that of PbO 2 electrodes. The relative surface area of the composite electrodes is approximately 2 times that of the pure PbO 2 electrodes. The structure test shows that the addition of ZrO 2 nanoparticles into the plating bath decreases the grain size of the PbO 2 –ZrO 2 nanocomposite electrodes. The anodic polarization curves show that the oxygen evolution overpotential of PbO 2 –ZrO 2 nanocomposite electrodes is higher than PbO 2 electrodes. The pollutant anodic oxidation experiment show that the PbO 2 –ZrO 2 nanocomposite electrode exhibited the better performance for the degradation of 4-chlorophenol than PbO 2 electrode, the removal ratio of COD reached 96.2%.

  13. Liquid Phase Sintering of (Ti,Zr)C with WC-Co.

    Ma, Taoran; Borrajo-Pelaez, Rafael; Hedström, Peter; Blomqvist, Andreas; Borgh, Ida; Norgren, Susanne; Odqvist, Joakim

    2017-01-11

    (Ti,Zr)C powder was sintered with WC-Co following an industrial process, including an isotherm at 1410 °C. A series of interrupted sintering trials was performed with the aim of studying the sintering behavior and the microstructural evolution during both solid-state and liquid-state sintering. Reference samples, using the same elemental compositions but with the starting components TiC and ZrC instead of (Ti,Zr)C, were also sintered. The microstructure was investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. It is found that the (Ti,Zr)C phase decomposes into Ti-rich and Zr-rich nano-scale lamellae before the liquid-state of the sintering initiates. The final microstructure consists of the binder and WC as well as two different γ phases, rich in either Ti (γ₁) or Zr (γ₂). The γ₂ phase grains have a core-shell structure with a (Ti,Zr)C core following the full sintering cycle. The major differences observed in (Ti,Zr)C with respect to the reference samples after the full sintering cycle were the referred core-shell structure and the carbide grain sizes; additionally, the microstructural evolution during sintering differs. The grain size of carbides (WC, γ₁, and γ₂) is about 10% smaller in WC-(Ti,Zr)C-Co than WC-TiC-ZrC-Co. The shrinkage behavior and hardness of both composites are reported and discussed.

  14. Liquid Phase Sintering of (Ti,ZrC with WC-Co

    Taoran Ma

    2017-01-01

    Full Text Available (Ti,ZrC powder was sintered with WC-Co following an industrial process, including an isotherm at 1410 °C. A series of interrupted sintering trials was performed with the aim of studying the sintering behavior and the microstructural evolution during both solid-state and liquid-state sintering. Reference samples, using the same elemental compositions but with the starting components TiC and ZrC instead of (Ti,ZrC, were also sintered. The microstructure was investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. It is found that the (Ti,ZrC phase decomposes into Ti-rich and Zr-rich nano-scale lamellae before the liquid-state of the sintering initiates. The final microstructure consists of the binder and WC as well as two different γ phases, rich in either Ti (γ1 or Zr (γ2. The γ2 phase grains have a core-shell structure with a (Ti,ZrC core following the full sintering cycle. The major differences observed in (Ti,ZrC with respect to the reference samples after the full sintering cycle were the referred core-shell structure and the carbide grain sizes; additionally, the microstructural evolution during sintering differs. The grain size of carbides (WC, γ1, and γ2 is about 10% smaller in WC-(Ti,ZrC-Co than WC-TiC-ZrC-Co. The shrinkage behavior and hardness of both composites are reported and discussed.

  15. Zr (IV COMPLEXES OF SOME NITROGEN-OXYGEN DONOR LIGANDS (SEMICARBAZONES & SALICYLALDAZINE

    Z F DAWOOD

    2002-06-01

    Full Text Available Complexes containing mixed ligands of zirconium (IV have been synthesized by the reaction of zirconium (IV nitrate (Zr(NO34, 5H2O with salicylaldazine (SAH2 and semicarbazone ligands benzaldehyde semicarbazone (BSCH, 4-methoxybenzaldehyde semicarbzone (MBSCH, 2-chlorobenzaldehyde semicrbazone (CISCH and cinnamaldehyde semicarbazone (CinSCH forming complexes of the type [Zr2(SAH2(SCH2](NO38 and [Zr2(SA2 (SC2](NO32 in neutral and basic medium respectively. The ligands and their complexes are characterized physico-chemically.

  16. Phase stability and elastic properties of β Ti-Nb-X (X = Zr, Sn) alloys: an ab initio density functional study

    K, Rajamallu; Niranjan, Manish K.; Ameyama, Kei; Dey, Suhash R.

    2017-12-01

    Alloying effects of Zr and Sn on β phase stability and elastic properties in Ti-Nb alloys are investigated within the framework of first-principles density functional theory. Our results suggest that the stability of β phase can be significantly enhanced by the addition of Zr and Sn in Ti-Nb alloys. The computed results indicate that Zr and Sn behave as strong β stabilizers in the Ti-Nb system. The elastic properties are found to be altered considerably by the addition of ternary alloying elements (Zr and Sn). The computed elastic moduli of Ti18.75 at%Nb6.25 at%Zr and Ti25 at%NbxZr compositions are found to be lower than that for Ti18.75 at%Nb6.25 at%Sn and Ti25 at%NbxSn system. The lowest value of ˜54 GPa is obtained for Ti25 at%Nb6.25 at%Zr composition. Furthermore, the directional Young’s modulus is found to be in the order of E 100 system.

  17. Composition dependences of crystal structure and electrical properties of epitaxial Pb(Zr,Ti)O3 films grown on Si and SrTiO3 substrates

    Okamoto, Shoji; Okamoto, Satoshi; Yokoyama, Shintaro; Akiyama, Kensuke; Funakubo, Hiroshi

    2016-10-01

    {100}-oriented Pb(Zr x ,Ti1- x )O3 (PZT) thin films of approximately 2 µm thickness and Zr/(Zr + Ti) ratios of 0.39-0.65 were epitaxially grown on (100)cSrRuO3//(100)SrTiO3 (STO) and (100)cSrRuO3//(100)cLaNiO3//(100)CeO2//(100)YSZ//(100)Si (Si) substrates having different thermal expansion coefficients by pulsed metal-organic chemical vapor deposition (MOCVD). The effects of Zr/(Zr + Ti) ratio and type of substrate on the crystal structure and dielectric, ferroelectric and piezoelectric properties of the films were systematically investigated. The X-ray diffraction measurement showed that both films changed from having a tetragonal symmetry to rhombohedral symmetry through the coexisting region with increasing Zr/(Zr + Ti) ratio. This region showed the Zr/(Zr + Ti) ratios of 0.45-0.59 for the films on the STO substrates that were wider than the films on the Si substrates. Saturation polarization values were minimum at approximately Zr/(Zr + Ti) = 0.50 for the films on the STO substrates, and no obvious Zr/(Zr + Ti) ratio dependence was detected in the films on the Si substrates. On the other hand, the maximum field-induced strain values measured by scanning force microscopy at approximately Zr/(Zr + Ti) = 0.50 at 100 kV/cm were about 0.5 and 0.1% in the films on the Si and STO, respectively.

  18. Characterization of gadolinium-doped ZrO2 films exposed to ultraviolet light

    Sanchez R, A.; Azorin, J.; Rivera, T.

    2003-01-01

    This paper presents the results of characterizing gadolinium-doped ZrO 2 (ZrO 2 : Gd) films, both morphological and respect to their optical and thermoluminescent properties after irradiation with ultraviolet (UV) light. ZrO 2 presented crystalline structure in monoclinic phase; its absorption spectrum exhibited a peak at 274 and 277 nm for films deposited on glass and quartz substrates respectively. The optimum concentration of the dopant was found to be 12%. ZrO 2 : Gd presents its maximum Tl response when it is exposed to lJV light of wavelength in the range from 240 to 245 nm; its glow curve shows apparently one peak, which probably is the overlapping of various peaks. (Author)

  19. Nano-scale chemical evolution in a proton-and neutron-irradiated Zr alloy

    Harte, Allan, E-mail: allan.harte@manchester.ac.uk [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Topping, M.; Frankel, P. [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Jädernäs, D. [Studsvik Nuclear AB, SE 611 82, Nyköping (Sweden); Romero, J. [Westinghouse Electric Company, Columbia, SC (United States); Hallstadius, L. [Westinghouse Electric Sweden AB, SE 72163 Västerås (Sweden); Darby, E.C. [Rolls Royce Plc., Nuclear Materials, Derby (United Kingdom); Preuss, M. [The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

    2017-04-15

    Proton-and neutron-irradiated Zircaloy-2 are compared in terms of the nano-scale chemical evolution within second phase particles (SPPs) Zr(Fe,Cr){sub 2} and Zr{sub 2}(Fe,Ni). This is accomplished through ultra-high spatial resolution scanning transmission electron microscopy and the use of energy-dispersive X-ray spectroscopic methods. Fe-depletion is observed from both SPP types after irradiation with both irradiative species, but is heterogeneous in the case of Zr(Fe,Cr){sub 2}, predominantly from the edge region, and homogeneously in the case of Zr{sub 2}(Fe,Ni). Further, there is evidence of a delay in the dissolution of the Zr{sub 2}(Fe,Ni) SPP with respect to the Zr(Fe,Cr){sub 2}. As such, SPP dissolution results in matrix supersaturation with solute under both irradiative species and proton irradiation is considered well suited to emulate the effects of neutron irradiation in this context. The mechanisms of solute redistribution processes from SPPs and the consequences for irradiation-induced growth phenomena are discussed. - Highlights: •Protons emulate the effects of neutron irradiation in the evolution of chemistry and morphology of second phase particles. •Detailed energy-dispersive X-ray spectroscopy reveals heterogeneity in Zr-Fe-Cr SPPs both before and after irradiation. •Zr-Fe-Ni SPPs are delayed in irradiation-induced dissolution due to their better self-solubility with respect to Zr-Fe-Cr.

  20. Roles of texture of Zr alloys in ZrO{sub 2} film formation and δ-hydride orientation near ZrO{sub 2}/Zr interface

    Qin, W.; Szpunar, J.A., E-mail: weq565@mail.usask.ca, E-mail: jerzy.szpunar@usask.ca [Univ. of Saskatchewan, Dept. of Mechanical Engineering, Saskatoon, SK (Canada); Kozinski, J., E-mail: janusz.kozinski@lassonde.yorku.ca [York Univ., Faculty of Science and Engineering, Toronto, ON (Canada)

    2014-07-01

    Oxidation and hydrogen embrittlement are related to formation of cracks and failure of Zr alloys used in nuclear reactor applications. An in-depth understanding of the formation of ZrO{sub 2} film and the hydride precipitation and orientation is important for improving the corrosion resistance of zirconium alloys. In this work a theoretical model is developed to analyze the microstructure of ZrO{sub 2} film formed on Zr alloys and the effect of stress that results from ZrO{sub 2} formation on hydride reorientation in the region near oxide/metal interface. Our work shows that the macroscopic stress produced due to Pilling-Bedworth ratio for ZrO{sub 2}/Zr could lead to the hydride re-orientation in the region near ZrO{sub 2}/Zr interface. Whether or not this effect can occur is dependent on the texture of the zirconium alloys. Control of texture of zirconium alloys can affect the microstructure of ZrO{sub 2} film and can be responsible for change of hydride orientation. (author)

  1. Low silicon U(Al,Si)3 stabilization by Zr addition

    Pizarro, L.M.; Alonso, P.R.; Rubiolo, G.H.

    2009-01-01

    Previous knowledge states that (U,Zr)Al 3 and U(Al,Si) 3 phases with Zr and Si content higher than 6 at.% (7.7 wt%) and 4 at.% (1.4 wt%), respectively, does not partially transform to UAl 4 at 600 o C. In this work, four alloys within the quaternary system U-Al-Si-Zr were made with a fixed nominal 0.18 at.% (0.1 wt%) Si content in order to assess the synergetic effect of both Zr and Si alloying elements to the thermodynamic stability of the (U,Zr)(Al,Si) 3 phase. Heat treatments at 600 deg. C were undertaken and samples were analyzed by means of XRD, EPMA and EDS techniques. A remarkable conclusion is that addition of 0.3 at.% Si in the (U,Zr)(Al,Si) 3 phase reduces in 2.7 at.% the necessary Zr content to inhibit its transformation to U(Al,Si) 4 .

  2. Influence of aluminium incorporation on the structure of ZrN films deposited at low temperatures

    Araiza, J J [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Paseo a la Bufa esq, Calzada Solidaridad s/n 98060, Zacatecas (Mexico); Sanchez, O [Departamento de Fisica e Ingenieria de Superficies, Instituto de Ciencia de Materiales de Madrid-CSIC, C/ Sor Juana Ines de la Cruz 3, 28049 Cantoblanco, Madrid (Spain)], E-mail: olgas@icmm.csic.es

    2009-06-07

    We have studied the influence of Al incorporation in the crystalline structure of ZrN thin films deposited by dc magnetron sputtering at low temperature. The amount of aluminium in the films depends directly on the power applied to the aluminium cathode during the deposition. Energy dispersive x-ray analysis and x-ray diffraction (XRD) were used to obtain the chemical composition and crystalline structure of the films, respectively. When Al atoms are incorporated into the ZrN coatings, the strong ZrN (2 0 0) orientation is modified by a combination of other ones such as ZrN (1 1 1), Zr{sub 3}N{sub 4} (2 1 1) and hexagonal AlN (1 0 0) as detected from the XRD spectra for high aluminium concentrations. Fourier-transform infrared spectroscopy allowed us to identify oxides and nitrides, ZrO, AlO and AlN, incorporated into the deposited films. The effect of a bias voltage applied to the substrate has also been investigated and related to the changes in the microstructure and in the nanohardness values of the ZrAlN films.

  3. Influence of aluminium incorporation on the structure of ZrN films deposited at low temperatures

    Araiza, J J; Sanchez, O

    2009-01-01

    We have studied the influence of Al incorporation in the crystalline structure of ZrN thin films deposited by dc magnetron sputtering at low temperature. The amount of aluminium in the films depends directly on the power applied to the aluminium cathode during the deposition. Energy dispersive x-ray analysis and x-ray diffraction (XRD) were used to obtain the chemical composition and crystalline structure of the films, respectively. When Al atoms are incorporated into the ZrN coatings, the strong ZrN (2 0 0) orientation is modified by a combination of other ones such as ZrN (1 1 1), Zr 3 N 4 (2 1 1) and hexagonal AlN (1 0 0) as detected from the XRD spectra for high aluminium concentrations. Fourier-transform infrared spectroscopy allowed us to identify oxides and nitrides, ZrO, AlO and AlN, incorporated into the deposited films. The effect of a bias voltage applied to the substrate has also been investigated and related to the changes in the microstructure and in the nanohardness values of the ZrAlN films.

  4. Investigation of nanostructured Al-10 wt.% Zr material prepared by ball milling for high temperature applications

    Prosviryakov, A.S.; Shcherbachev, K.D.; Tabachkova, N.Yu.

    2017-01-01

    Ground chips of as-cast Al-10 wt.% Zr alloy were subjected to mechanical alloying (MA) with 5 vol.% of nanodiamond addition in a high energy planetary ball-mill. The aim of this work was to investigate the microstructure, phase transformation and mechanical properties of the material both after MA and after subsequent annealing. Optical and transmission electron microscopes were used for morphological and microstructural analysis. The effect of milling time on powder microhardness, Al lattice parameter, lattice microstrain and crystallite size was determined. It was shown that mechanical alloying of as-cast Al-10wt.%Zr alloy during 20 h leads to a complete dissolution of the primary tetragonal Al 3 Zr crystals in aluminum. At the same time, the powder microhardness increases to 370 HV. Metastable cubic Al 3 Zr phase nanoparticles precipitate from the Al solution due to its decomposition after annealing, however, the Al solid solution remains supersaturated and nanocrystalline. Compression tests at room temperature and at 300 °C showed that the strength values of the hot-pressed samples reach 822 MPa and 344 MPa, respectively. - Highlights: •As-cast Al-10 wt.% Zr alloy was mechanically alloyed with 5 vol.% nanodiamond. •The primary tetragonal Al 3 Zr crystals were completely dissolved in Al after 20 h. •Cubic Al 3 Zr phase nanoparticles precipitated from Al solution after aging. •The aged bulk material showed a high strength at room and elevated temperatures.

  5. Thermoluminescent dosimetry of beta radiations of 90 Sr/ 90 Y using ZrO2: Eu

    Olvera T, L.; Azorin N, J.; Barrera S, M.; Soto E, A.M.; Rivera M, T.

    2005-01-01

    In this work the results of studying the thermoluminescent properties (TL) of the doped zirconium oxide with europium (ZrO 2 : Eu 3+ ) before beta radiations of 90 Sr/ 90 Y are presented. The powders of ZrO 2 : Eu 3+ were obtained by means of the sol-gel technique and they were characterized by means of thermal analysis and by X-ray diffraction. The powders of ZrO 2 : Eu 3+ , previously irradiated with beta particles of 90 Sr/ 90 Y, presented a thermoluminescent curve with two peaks at 204 and 292 C respectively. The TL response of the ZrO 2 : Eu 3+ as function of the absorbed dose was lineal from 2 Gy up to 90 Gy. The fading of the information of the ZrO 2 : Eu 3+ was of 10% the first 2 hours remaining almost constant the information by the following 30 days. The ZrO 2 doped with the (Eu 3+ ) ion it was found more sensitive to the beta radiation that the one of zirconium oxide without doping (ZrO 2 ) obtained by the same method. Those studied characteristics allow to propose to the doped zirconium oxide with europium like thermoluminescent dosemeter for the detection of the beta radiation. (Author)

  6. Alternative Zr alloys with irradiation resistant precipitates for high burnup BWR application

    Garzarolli, F.; Ruhmann, H.; Van Swan, L.

    2002-01-01

    In the core of BWRs, the second-phase particles (SPP) of Zircaloy-2 and Zircaloy-4, the Zr(FeCr) 2 and the Zr 2 (FeNi) phase, release Fe and dissolve. The degree of dissolution depends on initial size and fluence. These SPP, however, are important for the corrosion behavior of Zircaloy. Zircaloy shows an increase of corrosion at a certain burnup, depending on the initial SPP size and fast neutron fluence. Only Zr alloys with irradiation resistant SPP avoid this type of increased corrosion completely. Two types of irradiation resistant materials were considered. One is a Zr-Sn-Fe alloy containing the Zr 3 Fe phase, which is irradiation resistant under BWR conditions. The other material is a Zr-Sn-Nb alloy containing the irradiation resistant β-Nb phase. In-BWR tests have shown that a Sn content of >0.8% is mandatory to minimize the nodular corrosion. Two prototypes of irradiation resistant alloys, Zr1.3Sn0.25-0.3 Fe and Zr1Sn2-3Nb, were irradiated in a BWR for 1372 days to a fast fluence of 9 x 10 21 n/cm 2 (E > 1 MeV). These irradiation tests showed that Zr1.3Sn0.25-0.3 Fe has a little lower resistance against nodular corrosion than optimized LTP (Low Temperature Process) Zircaloy-2/4 and revealed that Zr1Sn2-3Nb is superior to LTP Zircaloy-2/4 with respect to nodular and shadow corrosion resistance. The BWR corrosion resistance of Zr1Sn2-3Nb depends on heat treatment. The lowest corrosion was observed with material fabricated completely in the α-range, but also material manufactured in the lower (α+β)-range exhibits low corrosion. Material fabricated in the upper (α+β)-range showed a somewhat higher corrosion, a corrosion behavior similar to LTP Zircaloy-2/4. As far as final annealing is concerned, a long time annealing at 540 deg C is superior to a standard recrystallization treatment (e.g., at 580 deg C), which still leads to a corrosion behavior that is better than stress relieved Zr1Sn2-3Nb. Zr1Sn2-3Nb is resistant to shadow corrosion, when fabricated

  7. Texture studies of Zr-2

    Madden, P.K.

    1976-09-01

    Basal pole figures of seven Zr-2 pressure tubes have been determined. The pole figures give texture factors but these do not correlate with the irradiation growth strains observed in SGHWR. Precautions taken in specimen preparation and in pole figure determination are described in detail. It is shown that any point on a pole figure may be unambiguously related to a defined set of coordinate axes in the pressure tube. (author)

  8. Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media

    Arana, J I; Bonilla, L L; Grahn, H T

    2011-01-01

    Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream with the flux of electrons can be constructed from their component wave fronts, whereas pulses advancing upstream do so slowly and experience saltatory motion: they change slowly in long intervals of time separated by fast transitions during which the pulses jump to the previous superlattice period. Photoexcited superlattices can also behave as oscillatory media and exhibit wave trains. (paper)

  9. Age differences in how consumers behave following exposure to DTC advertising.

    DeLorme, Denise E; Huh, Jisu; Reid, Leonard N

    2006-01-01

    This study was conducted to provide additional evidence on how consumers behave following direct-to-consumer (DTC) advertising exposure and to determine if there are differences in ad-prompted acts (drug inquiry and drug requests) between different age groups (i.e., older, mature, and younger adults). The results suggest that younger, mature, and older consumers are all moved to act by DTC drug ads, but that each age group behaves in different ways. Somewhat surprisingly, age was not predictive of ad-prompted behavior. DTC advertising was no more effective at moving older consumers to behave than their younger counterparts. These results suggest that age does not matter that much when it comes to the "moving power" of prescription drug advertising, even though research indicates that older consumers are more vulnerable to the persuasive effects of communication.

  10. Design of high-temperature high-strength Al-Ti-V-Zr alloys

    Lee, H.M.

    1990-01-01

    This paper reports that it seems plausible to develop high-strength Al-base alloys useful up to 698K in view of the behavior of nickel base superalloys which resist degradation of mechanical properties to 75 pct of their absolute melting temperature. For high temperature Al alloys, the dispersed hardening phase must not undergo phase transformation to an undesirable phase during long time exposure at the temperature of interest. An additional factor to be considered is the stability of the hardening phase with respect to Ostwald ripening. This coarsening resistance is necessary so that the required strength level can be maintained after the long-time service at high temperatures. The equilibrium crystal structures of Al 3 Ti, Al 3 V and Al 3 Zr are tetragonal D0 22 , D0 22 and D0 23 , respectively. At the temperatures of interest, around 698K, vanadium and titanium are mutually substitutable in the form of Al 3 (Ti, V). Much of titanium and vanadium can be substituted for zirconium in the D0 23 - type Al 3 Zr compound, creating Al 3 (Ti, Zr) and Al 3 (V, Zr), respectively. In particular, it has been reported that fcc L1 2 -structured Al 3 M dispersoids form in the rapidly solidified Al-V-Zr and Al-Ti-Zr systems and both L1 2 and D0 23 -structured Al 3 M phases showed slow coarsening kinetics

  11. Cu-Zr-Ag bulk metallic glasses based on Cu8Zr5 icosahedron

    Xia Junhai; Qiang Jianbing; Wang Yingmin; Wang Qing; Dong Chuang

    2007-01-01

    Based on the cluster line criterion, the Ag addition into the Cu 8 Zr 5 cluster composition is investigated for the search of ternary Cu-Zr-Ag bulk metallic glasses with high glass forming abilities. Two initial binary compositions Cu 0.618 Zr 0.382 and Cu 0.64 Zr 0.36 are selected. The former one corresponds to a deep eutectic point; it is also the composition of the Cu 8 Zr 5 icosahedron, which is derived from the Cu 8 Zr 3 structure. The latter one, which can be regarded as the Cu 8 Zr 5 cluster plus a glue atom Cu, is the best glass-forming composition in the Cu-Zr binary system. Two composition lines (Cu 0.618 Zr 0.382 ) 1-x Ag x and (Cu 0.64 Zr 0.36 ) 1-x Ag x are thus constructed in the Cu-Zr-Ag system by linking these two compositions with the third constitute Ag. A series of Cu-Zr-Ag bulk metallic glasses are found with 2-8 at.% Ag contents in both composition lines. The optimum composition (Cu 0.618 Zr 0.382 ) 0.92 Ag 0.08 within the searched region with the highest T g /T l = 0.633, is located along the cluster line (Cu 0.618 Zr 0.382 ) 1-x Ag x , where the deep eutectic Cu 0.618 Zr 0.382 exactly corresponds to the dense packing cluster Cu 8 Zr 5 . The alloying mechanism is discussed in the light of atomic size and electron concentration factors

  12. Microstructures and phase transformations of Ti-30Zr-xNb (x = 5, 7, 9, 13 at.%) shape memory alloys

    Qu, Wentao; Sun, Xuguang; Yuan, Bifei [School of Mechanical Engineering, Xi' an Shiyou University, Xi' an 710065 (China); Xiong, Chengyang; Zhang, Fei [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Yan, E-mail: liyan@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Sun, Baohui [Lanzhou Seemine SMA Co. Ltd., Lanzhou 730010 (China)

    2016-12-15

    The microstructures, phase transformations and shape memory properties of Ti-30Zr-xNb (x = 5, 7, 9, 13 at.%) alloys were investigated. The X-ray diffraction and transmission electron microscopy observations showed that the Ti-30Zr-5Nb, Ti-30Zr-7/9Nb and Ti-30Zr-13Nb alloys were composed of the hcp α′-martensite, orthorhombic α″-martensite and β phases, respectively. The results indicated the enhanced β-stabilizing effect of Nb in Ti-30Zr-xNb alloys than that in Ti-Nb alloys due to the high content of Zr. The differential scanning calorimetry test indicated that the Ti-30Zr-5Nb alloy displayed a reversible transformation with a high martensitic transformation start temperature of 776 K and a reverse martensitic transformation start temperature (A{sub s}) of 790 K. For the Ti-30Zr-7Nb and Ti-30Zr-9Nb alloys, the martensitic transformation temperatures decreased with the increasing Nb content. Moreover, an ω phase transformation occurred in the both alloys upon heating at a temperature lower than the corresponding A{sub s}, which is prompted by more addition of Nb. Although the critical stress in tension of the three martensitic alloys decreased with increasing Nb content, the Ti-30Zr-9Nb alloy showed a critical stress of as high as 300 MPa. Among all the alloys, the Ti-30Zr-9Nb alloy exhibited the maximum shape memory effect of 1.61%, due to the lowest critical stress for the martensite reorientation. - Highlights: •Ti-30Zr-5Nb alloy is composed of hcp α′-martensite with the M{sub s} of 776 K. •Ti-30Zr-7Nb and Ti-30Zr-9Nb alloys are predominated by orthorhombic α″-martensite. •Ti-30Zr-13Nb alloy consists of a single β phase due to the β-stabilizing effect of Nb. •The martensitic transformation temperatures decrease with increasing Nb content. •Ti-30Zr-9Nb alloy shows the maximum shape memory effect of 1.61%.

  13. Influence of ZrO{sub 2} nanoparticles and thermal treatment on the properties of PMMA/ZrO{sub 2} hybrid coatings

    Reyes-Acosta, M.A. [Instituto Politécnico Nacional, CICATA-Altamira, CIAMS (Mexico); Instituto Politécnico Nacional, CICATA-Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps. (Mexico); Torres-Huerta, A.M., E-mail: atorresh@ipn.mx [Instituto Politécnico Nacional, CICATA-Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps. (Mexico); Domínguez-Crespo, M.A. [Instituto Politécnico Nacional, CICATA-Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps. (Mexico); Flores-Vela, A.I. [Instituto Politécnico Nacional, CMP+L, Av. Acueducto s/n, Barrio La Laguna, Col. Ticomán, C.P. 07340 México D.F. (Mexico); Dorantes-Rosales, H.J. [Instituto Politécnico Nacional, SEPI-ESIQIE, Departamento de Metalurgia, C.P. 07738 México D.F. (Mexico); Ramírez-Meneses, E. [Departamento de Ingeniería y Ciencias Químicas, Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Distrito Federal C.P. 01219 (Mexico)

    2015-09-15

    Highlights: • PMMA/ZrO{sub 2} nanocomposites were prepared by melt blending in a single screw extruder. • The nanoparticles of m-, t-ZrO{sub 2} were successfully synthesized using sol–gel technique. • The prepared PMMA/ZrO{sub 2} nanocomposites have better UV protection than pure PMMA. • The thermal stability of the PMMA increases with low amount of ZrO{sub 2} nanoparticles. • PMMA/ZrO{sub 2} nanocomposites show superior values of elastic modulus and hardness. - Abstract: In this work, ZrO{sub 2} nanoparticles were synthesized by the sol–gel method, treated thermally at different temperatures (400, 600 and 800 °C), and added to a polymer matrix in two different weight percentages (0.5 and 1) by single screw extrusion in order to determine the influence of these parameters on the thermal stability and UV radiation resistance of PMMA/ZrO{sub 2} composites. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), ultraviolet–visible spectroscopy (UV–Vis), thermogravimetric analysis (TGA) and nanoindentation techniques were used to evaluate the structural, morphological, optical, thermal and mechanical properties of as-prepared composites. The average crystallite sizes for ZrO{sub 2} sintered at 600 and 800 °C were about 17 and 26 nm, respectively. It was found that the incorporation of a low percentage of ZrO{sub 2} nanoparticles increased the thermal properties of PMMA as well as its hardness and elastic modulus. The degradation temperature at 10 wt.% loss of the PMMA/ZrO{sub 2} (0.5 wt.%, 400 °C) nanocomposite was approximately 48 °C higher than that of pure PMMA. The absorption in the UV region was increased according to the ZrO{sub 2} heat treatment temperature and amount added to the polymer matrix.

  14. Dendritic solidification and thermal expansion of refractory Nb-Zr alloys investigated by electrostatic levitation

    Yang, S.J.; Hu, L.; Wang, L.; Wei, B. [Northwestern Polytechnical University, Department of Applied Physics, Xi' an (China)

    2017-05-15

    The dendritic growth and thermal expansion of isomorphous refractory Nb-5%Zr, Nb-10%Zr, and Nb-15%Zr alloys were studied by electrostatic levitation technique. The obtained maximum undercoolings for the three alloys were 534 (0.2T{sub L}), 498 (0.19T{sub L}), and 483 K (0.18T{sub L}), respectively. Within these undercooling ranges, the dendritic growth velocities of the three alloys all exhibited power laws, and achieved 38.5, 34.0, and 27.1 m s{sup -1} at each maximum undercooling. The microstructures were characterized by coarse dendrites at small undercooling, while they transformed into refined dendrites under large undercooling condition. In addition, the measured thermal expansion coefficients of solid Nb-Zr alloys increased linearly with temperature. The values at liquid state were more than double of those at solid state, which also displayed linear dependence on temperature. (orig.)

  15. Enhanced flux pinning in MOCVD-YBCO films through Zr additions : systematic feasibility studies.

    Aytug, T.; Paranthaman, M.; Specht, E. D.; Zhang, Y.; Kim, K.; Zuev, Y. L.; Cantoni, C.; Goyal, A.; Christen, D. K.; Maroni, V. A.; Chen, Y.; Selvamanickam, V.; ORNL; SuperPower, Inc.

    2010-01-01

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions {le} 7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO{sub 3} nanodots.

  16. Enhanced flux pinning in MOCVD-YBCO films through Zr additions: systematic feasibility studies

    Aytug, T; Paranthaman, M; Specht, E D; Zhang, Y; Kim, K; Zuev, Y L; Cantoni, C; Goyal, A; Christen, D K; Maroni, V A; Chen, Y; Selvamanickam, V

    2010-01-01

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa 2 Cu 3 O 7-δ (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions ≤7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO 3 nanodots.

  17. Enhanced flux pinning in MOCVD-YBCO films through Zr additions: systematic feasibility studies

    Aytug, T; Paranthaman, M; Specht, E D; Zhang, Y; Kim, K; Zuev, Y L; Cantoni, C; Goyal, A; Christen, D K [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Maroni, V A [Argonne National Laboratory, Argonne, IL 60439 (United States); Chen, Y; Selvamanickam, V, E-mail: aytugt@ornl.go [SuperPower, Incorporated, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2010-01-15

    Systematic effects of Zr additions on the structural and flux pinning properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films deposited by metal-organic chemical vapor deposition (MOCVD) have been investigated. Detailed characterization, conducted by coordinated transport, x-ray diffraction, scanning and transmission electron microscopy analyses, and imaging Raman microscopy have revealed trends in the resulting property/performance correlations of these films with respect to varying mole percentages (mol%) of added Zr. For compositions {<=}7.5 mol%, Zr additions lead to improved in-field critical current density, as well as extra correlated pinning along the c-axis direction of the YBCO films via the formation of columnar, self-assembled stacks of BaZrO{sub 3} nanodots.

  18. Microstructure and mechanical properties of Ti-15Zr alloy used as dental implant material.

    Medvedev, Alexander E; Molotnikov, Andrey; Lapovok, Rimma; Zeller, Rolf; Berner, Simon; Habersetzer, Philippe; Dalla Torre, Florian

    2016-09-01

    Ti-Zr alloys have recently started to receive a considerable amount of attention as promising materials for dental applications. This work compares mechanical properties of a new Ti-15Zr alloy to those of commercially pure titanium Grade4 in two surface conditions - machined and modified by sand-blasting and etching (SLA). As a result of significantly smaller grain size in the initial condition (1-2µm), the strength of Ti-15Zr alloy was found to be 10-15% higher than that of Grade4 titanium without reduction in the tensile elongation or compromising the fracture toughness. The fatigue endurance limit of the alloy was increased by around 30% (560MPa vs. 435MPa and 500MPa vs. 380MPa for machined and SLA-treated surfaces, respectively). Additional implant fatigue tests showed enhanced fatigue performance of Ti-15Zr over Ti-Grade4. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Comments on the equilibrium diagram of the Ti-Zr system

    Ruch, M.; Arias, D.

    1993-01-01

    The Ti-Zr system is a continuous series of solid solutions in both the α- and β-phases, with a congruent minimum at Ti-50at%Zr. The equilibrium diagram has been reviewed by Murray in 1981, who accepts the α/β temperature for this minimum determined by Farrar and Adler by metallographic techniques. Etchessahar and Debuigne measured by dilatometry a transformation temperature of (894 ±)K and (859±2)K for α/α + β and β/α + β respectively, and later in a high temperature Calvet microcalorimeter, 883K. Blacktop et al find that this value is consistent with their measurements of the α/β transformation temperature in Ti-40%Zr and Ti-60%Zr in a high temperature calorimeter. In the present work, the α/β transformation temperature was measured by several techniques. The effect of impurities is considered in both transformation temperature and microstructure of product phases

  20. Teaching respect: a philosophical analysis

    L. van Rooyen

    2000-03-01

    Full Text Available According to a Zulu proverb a human being can only become truly human because of others. Each person can only become more human, more himself- regardless of his sex - through the co-involvement of others. It is the love for one’s neighbour and the respect one has for him/her as a person which makes one consider the other party's feelings, viewpoints and circumstances. In order to arrive at a situation of peaceful coexistence it is important to realize that human attitudes and a mature life style evolve through a process of learning and interaction with others. It is a timeconsuming and costly process which starts at infancy and continues throughout someone's life. Instruction concerning interpersonal relations and the teaching of respect cannot be confined to individual lessons or working sessions at home or in school. Discussions and conversations concerning interpersonal relations need to form an integral and natural part of a child’s life within the home environment and throughout the pupil's school career. It is senseless if educators talk about the importance of teaching respect only to reveal disrespectful behaviour themselves, or to talk about the importance of self-esteem in the paying of respect whilst causing children to feel negative about themselves. To be able to express respect to other human beings, one needs to be respected. A child needs to experience how it feels when homage is paid. The following rule of life applies in this regard: one can never give if one has never received respect.

  1. High-temperature deformation of dispersion-strengthened Cu-Zr-Ti-C alloys

    Palma, Rodrigo H.; Sepulveda, Aquiles; Espinoza, Rodrigo; Dianez, M. Jesus; Criado, Jose M.; Sayagues, M. Jesus

    2005-01-01

    The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO 2 and Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO 2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10 -3 and 0.85 x 10 -4 s -1 were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 and the Cu-5 vol.% ZrO 2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO 2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures

  2. Hippocampal activity during transient respiratory events in the freely behaving cat

    Poe, G R; Kristensen, Morten Pilgaard; Rector, D M

    1996-01-01

    We measured dorsal hippocampal activity accompanying sighs and apnea using reflectance imaging and electrophysiologic measures in freely behaving cats. Reflected 660-nm light from a 1-mm2 area of CA1 was captured during sighs and apnea at 25 Hz through a coherent image conduit coupled to a charge...

  3. BEHAVE: fire behavior prediction and fuel modeling system--FUEL subsystem

    Robert E. Burgan; Richard C. Rothermel

    1984-01-01

    This manual documents the fuel modeling procedures of BEHAVE--a state-of-the-art wildland fire behavior prediction system. Described are procedures for collecting fuel data, using the data with the program, and testing and adjusting the fuel model.

  4. An Abstract Coalgebraic Approach to Process Equivalence for Well- Behaved Operational Semantics

    Klin, Bartek

    This thesis is part of the programme aimed at finding a mathematical theory of well-behaved structural operational semantics. General and basic results shown in 1997 in a seminal paper by Turi and Plotkin are extended in two directions, aiming at greater expressivity of the framework. The so-call...

  5. BEHAVE: fire behavior prediction and fuel modeling system-BURN Subsystem, part 1

    Patricia L. Andrews

    1986-01-01

    Describes BURN Subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.

  6. A lightweight telemetry system for recording neuronal activity in freely behaving small animals

    Schregardus, D.S.; Pieneman, A.W.; ter Maat, A.; Brouwer, T.J.F.; Gahr, M.L.

    2006-01-01

    A miniature lightweight radio telemetric device is described which is shown to be suitable for recording neuronal activity in freely behaving animals. Its size (12 × 5 × 8 mm) and weight (1.0-1.1 g with batteries, 0.4-0.5 g without) make the device particularly suitable for recording neuronal units

  7. Nuclear orientation of 9597Nb and 95Zr in ZrFe2

    Krane, K.S.; Olsen, C.E.; Rosenblum, S.S.; Steyert, W.A.

    1976-01-01

    The angular distribution anisotropies of γ rays were measured following the decays of 95 , 97 Nb and 95 Zr oriented at low temperatures in the ferromagnetic Laves phase compound ZrFe 2 . The magnetic hyperfine field of Nb in ZrFe 2 was deduced to be 9.4+-1.6 T; that of Zr in ZrFe 2 was estimated to be 15+-4 T. The nuclear magnetic moment of 97 Nb was deduced to be μ = (7.5+-1.4) μ/subN/

  8. Electronic properties and bonding in Zr Hx thin films investigated by valence-band x-ray photoelectron spectroscopy

    Magnuson, Martin; Schmidt, Susann; Hultman, Lars; Högberg, Hans

    2017-11-01

    The electronic structure and chemical bonding in reactively magnetron sputtered Zr Hx (x =0.15 , 0.30, 1.16) thin films with oxygen content as low as 0.2 at.% are investigated by 4d valence band, shallow 4p core-level, and 3d core-level x-ray photoelectron spectroscopy. With increasing hydrogen content, we observe significant reduction of the 4d valence states close to the Fermi level as a result of redistribution of intensity toward the H 1s-Zr 4d hybridization region at ˜6 eV below the Fermi level. For low hydrogen content (x =0.15 , 0.30), the films consist of a superposition of hexagonal closest-packed metal (α phase) and understoichiometric δ -Zr Hx (Ca F2 -type structure) phases, while for x =1.16 , the films form single-phase Zr Hx that largely resembles that of stoichiometric δ -Zr H2 phase. We show that the cubic δ -Zr Hx phase is metastable as thin film up to x =1.16 , while for higher H contents the structure is predicted to be tetragonally distorted. For the investigated Zr H1.16 film, we find chemical shifts of 0.68 and 0.51 eV toward higher binding energies for the Zr 4 p3 /2 and 3 d5 /2 peak positions, respectively. Compared to the Zr metal binding energies of 27.26 and 178.87 eV, this signifies a charge transfer from Zr to H atoms. The change in the electronic structure, spectral line shapes, and chemical shifts as a function of hydrogen content is discussed in relation to the charge transfer from Zr to H that affects the conductivity by charge redistribution in the valence band.

  9. States in 94Zr from 94Zr(d,d')94Zr* at 15.5 Mev

    Frota-Pessoa, E.; Joffily, S.

    1986-01-01

    94 energy levels up to approx. 4.3 Mev excitation energy are studied in the 94 Zr(d,d') 94 Zr* reaction. Deuterons had a bombarding energy of 15.5 MeV. The emergent deuterons were analysed by a magnetic spectrograph and the detector was nuclear emulsion. The resolution in energy was about 11 KeV. The distorted-wave analysis was used to determine the l transferred, the β 2 l and J Π values for some 94 Zr excited states. These results are compared with previous ones. 32 levels of excitation energy in 94 Zr were found which did not appear in previous 94 Zr(d,d') reactions. 20 levels do not correspond to the ones. (Author) [pt

  10. Zr inclusions in actinide—Zr alloys: New data and ideas about how they form

    Janney, Dawn E.; O'Holleran, Thomas P.

    2015-01-01

    High-Zr inclusions are common in actinide—Zr alloys despite phase diagrams indicating that these alloys should not contain a high-Zr phase. The inclusions may contain enough Zr to cause significant differences between bulk compositions and those of inclusion-free areas, leading to possible errors in interpreting data if the inclusions are not considered. This paper presents data from high-Zr inclusions in a complex U—Np—Pu—Am—Zr—RE alloy. It is suggested that the high-Zr inclusions nucleated as high-Zr solid solutions at interfaces with high-actinide RE liquids, then unmixed to form nanometer-scale high-actinide sub-inclusions.

  11. Microstructural evolution of Ni40Zr60 alloy during early stage of mechanical alloying of intermetallic compounds NiZr2 and Ni11Zr9

    Lee Peeyew; Koch, C.C.

    1994-01-01

    The microstructural change of Ni 40 Zr 60 alloy during mechanical alloying of mixtures of the intermetallic compounds NiZr 2 and Ni 11 Zr 9 has been studied by transmission electron microscopy. A specific ''cauliflower'' phase was formed during early stage of mechanical alloying process. It is suggested that the solid state reaction between intermetallic compounds NiZr 2 and Ni 11 Zr 9 is not the only origin for the formation of the ''cauliflower'' phase. ((orig.))

  12. Synthesis of Zr2WP2O12/ZrO2 Composites with Adjustable Thermal Expansion

    Zhiping Zhang

    2017-11-01

    Full Text Available Zr2WP2O12/ZrO2 composites were fabricated by solid state reaction with the goal of tailoring the thermal expansion coefficient. XRD, SEM and TMA were used to investigate the composition, microstructure, and thermal expansion behavior of Zr2WP2O12/ZrO2 composites with different mass ratio. Relative densities of all the resulting Zr2WP2O12/ZrO2 samples were also tested by Archimedes' methods. The obtained Zr2WP2O12/ZrO2 composites were comprised of orthorhombic Zr2WP2O12 and monoclinic ZrO2. As the increase of the Zr2WP2O12, the relative densities of Zr2WP2O12/ZrO2 ceramic composites increased gradually. The coefficient of thermal expansion of the Zr2WP2O12/ZrO2 composites can be tailored from 4.1 × 10−6 K−1 to −3.3 × 10−6 K−1 by changing the content of Zr2WP2O12. The 2:1 Zr2WP2O12/ZrO2 specimen shows close to zero thermal expansion from 25 to 700°C with an average linear thermal expansion coefficient of −0.09 × 10−6 K−1. These adjustable and near zero expansion ceramic composites will have great potential application in many fields.

  13. Synthesis of Zr2WP2O12/ZrO2 Composites with Adjustable Thermal Expansion.

    Zhang, Zhiping; Sun, Weikang; Liu, Hongfei; Xie, Guanhua; Chen, Xiaobing; Zeng, Xianghua

    2017-01-01

    Zr 2 WP 2 O 12 /ZrO 2 composites were fabricated by solid state reaction with the goal of tailoring the thermal expansion coefficient. XRD, SEM and TMA were used to investigate the composition, microstructure, and thermal expansion behavior of Zr 2 WP 2 O 12 /ZrO 2 composites with different mass ratio. Relative densities of all the resulting Zr 2 WP 2 O 12 /ZrO 2 samples were also tested by Archimedes' methods. The obtained Zr 2 WP 2 O 12 /ZrO 2 composites were comprised of orthorhombic Zr 2 WP 2 O 12 and monoclinic ZrO 2 . As the increase of the Zr 2 WP 2 O 12 , the relative densities of Zr 2 WP 2 O 12 /ZrO 2 ceramic composites increased gradually. The coefficient of thermal expansion of the Zr 2 WP 2 O 12 /ZrO 2 composites can be tailored from 4.1 × 10 -6 K -1 to -3.3 × 10 -6 K -1 by changing the content of Zr 2 WP 2 O 12 . The 2:1 Zr 2 WP 2 O 12 /ZrO 2 specimen shows close to zero thermal expansion from 25 to 700°C with an average linear thermal expansion coefficient of -0.09 × 10 -6 K -1 . These adjustable and near zero expansion ceramic composites will have great potential application in many fields.

  14. Oxidation behavior of Zr and its alloys

    Costa, I.; Ramanathan, L.V.

    1984-01-01

    The environment effect, material composition, thermal treatment and superficial treatment on the oxidation behavior of Zr, Zircaloy-4 and Zr - 2,5% Nb, in the temperature range of 400 - 900 0 C, by thermogravimetry were studied. (E.G.) [pt

  15. Fabrication of low thermal expansion SiC/ZrW{sub 2}O{sub 8} porous ceramics

    Poowancum, A; Matsumaru, K; Juarez-Ramirez, I; Ishizaki, K [Department of Mechanical Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Torres-Martinez, L M [Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, San Nicolas de los Garza, NL, C.P. 66451 (Mexico); Fu, Z Y [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei, 430070 (China); Lee, S W, E-mail: anurat@ishizaki.nagaokaut.ac.jp [Department of Environment Engineering, Sun Moon University, 100, Kalsan-ri, Tangjeong-myeon, Asan, Chungnam 336-708 (Korea, Republic of)

    2011-03-15

    Low or zero thermal expansion porous ceramics are required for several applications. In this work near zero thermal expansion porous ceramics were fabricated by using SiC and ZrW{sub 2}O{sub 8} as positive and negative thermal expansion materials, respectively, bonded by soda lime glass. The mixture of SiC, ZrW{sub 2}O{sub 8} and soda lime glass was sintered by Pulsed Electric Current Sintering (PECS, or sometimes called Spark Plasma Sintering, SPS) at 700 deg. C. Sintered samples with ZrW{sub 2}O{sub 8} particle size smaller than 25 {mu}m have high thermal expansion coefficient, because ZrW{sub 2}O{sub 8} has the reaction with soda lime glass to form Na{sub 2}ZrW{sub 3}O{sub 12} during sintering process. The reaction between soda lime glass and ZrW{sub 2}O{sub 8} is reduced by increasing particle size of ZrW{sub 2}O{sub 8}. Sintered sample with ZrW{sub 2}O{sub 8} particle size 45-90 {mu}m shows near zero thermal expansion.

  16. Microemulsion and Sol-Gel Synthesized ZrO2-MgO Catalysts for the Liquid-Phase Dehydration of Xylose to Furfural

    Almudena Parejas

    2017-12-01

    Full Text Available Two series of catalysts were prepared by sol-gel and microemulsion synthetic procedure (SG and ME, respectively. Each series includes both pure Mg and Zr solids as well as Mg-Zr mixed solids with 25%, 50% and 75% nominal Zr content. The whole set of catalysts was characterized from thermal, structural and surface chemical points of view and subsequently applied to the liquid-phase xylose dehydration to furfural. Reactions were carried out in either a high-pressure autoclave or in an atmospheric pressure multi-reactor under a biphasic (organic/water reaction mixture. Butan-2-ol and toluene were essayed as organic solvents. Catalysts prepared by microemulsion retained part of the surfactant used in the synthetic procedure, mainly associated with the Zr part of the solid. The MgZr-SG solid presented the highest surface acidity while the Mg3Zr-SG one exhibited the highest surface basicity among mixed systems. Xylose dehydration in the high-pressure system and with toluene/water solvent mixture led to the highest furfural yield. Moreover, the yield of furfural increases with the Zr content of the catalyst. Therefore, the catalysts constituted of pure ZrO2 (especially Zr-SG are the most suitable to carry out the process under study although MgZr mixed solids could be also suitable for overall processes with additional reaction steps.

  17. Microemulsion and Sol-Gel Synthesized ZrO₂-MgO Catalysts for the Liquid-Phase Dehydration of Xylose to Furfural.

    Parejas, Almudena; Montes, Vicente; Hidalgo-Carrillo, Jesús; Sánchez-López, Elena; Marinas, Alberto; Urbano, Francisco J

    2017-12-18

    Two series of catalysts were prepared by sol-gel and microemulsion synthetic procedure (SG and ME, respectively). Each series includes both pure Mg and Zr solids as well as Mg-Zr mixed solids with 25%, 50% and 75% nominal Zr content. The whole set of catalysts was characterized from thermal, structural and surface chemical points of view and subsequently applied to the liquid-phase xylose dehydration to furfural. Reactions were carried out in either a high-pressure autoclave or in an atmospheric pressure multi-reactor under a biphasic (organic/water) reaction mixture. Butan-2-ol and toluene were essayed as organic solvents. Catalysts prepared by microemulsion retained part of the surfactant used in the synthetic procedure, mainly associated with the Zr part of the solid. The MgZr-SG solid presented the highest surface acidity while the Mg3Zr-SG one exhibited the highest surface basicity among mixed systems. Xylose dehydration in the high-pressure system and with toluene/water solvent mixture led to the highest furfural yield. Moreover, the yield of furfural increases with the Zr content of the catalyst. Therefore, the catalysts constituted of pure ZrO₂ (especially Zr-SG) are the most suitable to carry out the process under study although MgZr mixed solids could be also suitable for overall processes with additional reaction steps.

  18. Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

    Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

    2017-08-08

    The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

  19. Renewing the Respect for Similarity

    Shimon eEdelman

    2012-07-01

    Full Text Available In psychology, the concept of similarity has traditionally evoked a mixture of respect, stemmingfrom its ubiquity and intuitive appeal, and concern, due to its dependence on the framing of the problemat hand and on its context. We argue for a renewed focus on similarity as an explanatory concept, bysurveying established results and new developments in the theory and methods of similarity-preservingassociative lookup and dimensionality reduction — critical components of many cognitive functions, aswell as of intelligent data management in computer vision. We focus in particular on the growing familyof algorithms that support associative memory by performing hashing that respects local similarity, andon the uses of similarity in representing structured objects and scenes. Insofar as these similarity-basedideas and methods are useful in cognitive modeling and in AI applications, they should be included inthe core conceptual toolkit of computational neuroscience.

  20. Mechanical spectroscopy study of the Cu36Zr59Al5 and Cu54Zr40Al6 amorphous alloys

    Paulo Wilmar Barbosa Marques

    2012-12-01

    Full Text Available A mechanical spectroscopy study of Cu-Zr-Al bulk metallic glasses, was performed with two types of equipment: a Kê-type inverted torsion pendulum and an acoustic elastometer, working in the frequency ranges of Hz and kHz, respectively, with a heating rate of 1 K/min. The analysis of the anelastic relaxation shows similar spectra for both types of equipment resulting in internal friction patterns that vary with temperature and are not reproducible at each thermal cycle. The normalized of the square of the frequency changes from the first to later measurement cycles. These results indicate that the specimens of Cu-Zr-Al alloys were changing by mechanical relaxation, owing to the motion of atoms or clusters in the glassy state and possible "defects" produced during the processing of alloys.

  1. International science conference RESpect report

    Radim Rybár

    2010-07-01

    Full Text Available Report is dedicated to aspects of conceiving the number of scientific magazine Acta Montanistica Slovaca, which purpose wasto publish specific key reports from the sixth year of international science conference RESpect 2011. The main aspect in the decisionprocess was to cover the conference agenda, complexity of the global problematic understanding, the subject of examination actualityand the results achievement level. The choice at the same time points on the technological, evaluative, environmental, economicaland application aspects of the RES usage, with accent on the Middle Europe region conditions.

  2. Mechanical properties investigation on single-wall ZrO2 nanotubes: A finite element method with equivalent Poisson's ratio for chemical bonds

    Yang, Xiao; Li, Huijian; Hu, Minzheng; Liu, Zeliang; Wärnå, John; Cao, Yuying; Ahuja, Rajeev; Luo, Wei

    2018-04-01

    A method to obtain the equivalent Poisson's ratio in chemical bonds as classical beams with finite element method was proposed from experimental data. The UFF (Universal Force Field) method was employed to calculate the elastic force constants of Zrsbnd O bonds. By applying the equivalent Poisson's ratio, the mechanical properties of single-wall ZrNTs (ZrO2 nanotubes) were investigated by finite element analysis. The nanotubes' Young's modulus (Y), Poisson's ratio (ν) of ZrNTs as function of diameters, length and chirality have been discussed, respectively. We found that the Young's modulus of single-wall ZrNTs is calculated to be between 350 and 420 GPa.

  3. Structural Studies of dielectric HDPE+ZrO2 polymer nanocomposites: filler concentration dependences

    Nabiyev, A. A.; Islamov, A. Kh; Maharramov, A. M.; Nuriyev, M. A.; Ismayilova, R. S.; Doroshkevic, A. S.; Pawlukojc, A.; Turchenko, V. A.; Olejniczak, A.; Rulev, M. İ.; Almasan, V.; Kuklin, A. I.

    2018-03-01

    Structural properties of HDPE+ZrO2 polymer nanocomposites thin films of 80-100μm thicknesses were investigated using SANS, XRD, Laser Raman and FTIR spectroscopy. The mass fraction of the filler was 1, 3, 10, and 20%. Results of XRD analysis showed that ZrO2 powder was crystallized both in monoclinic and in cubic phase under normal conditions. The percentages of monoclinic and cubic phase were found to be 99.8% and 0.2%, respectively. It was found that ZrO2 nanoparticles did not affect the main crystal and chemical structure of HDPE, but the degree of crystallinity of the polymer decreases with increasing concentration of zirconium oxide. SANS experiments showed that at ambient conditions ZrO2 nanoparticles mainly distributed like mono-particles in the polymer matrix at all concentrations of filler.The structure of HDPE+ZrO2 does not changes up to 132°C at 1-3% of filler, excepting changing of the polymer structure at temperatures upper 82°C. At high concentrations of filler 10-20% the aggregation of ZrO2 nanoparticles occurs, forming domains of 2.5μm. The results of Raman and FTIR spectroscopy did not show additional specific chemical bonds between the filler and the polymer matrix. New peaks formation was not observed. These results suggest that core-shell structure does not exist in the polymer nanocomposite system.

  4. Preparation and determination of the luminescent characteristics of ZrO2 in powder

    Rivera M, T.; Olvera T, L.; Azorin N, J.; Soto E, A.M.; Velazquez O, C.; Campero C, A.

    2004-01-01

    In this work the luminescent characteristics of the ZrO 2 are presented using the method of Thermally Stimulated Luminescence (TSL), also called thermoluminescence (Tl). The powders of ZrO 2 were obtained by two preparation methods: for precipitation and for evaporation of Sol-gel. The luminescent characteristics of the ZrO 2 are determined using a lamp of radiation of UV light and a radiation source of beta particles of 90 Sr/ 90 Y. Using the method of thermal stimulation the curve representative thermoluminescent of the previously irradiated material was obtained. The curve Tl of the ZrO 2 irradiated with UV light presents a maximum in 180 C. Likewise, the spectrum of the curve Tl of the ZrO 2 irradiated with particles beta presents a maximum centered in 181 C. While using gamma radiation like excitement source one has a spectrum with a peak centered in 184 C. When subjecting the materials obtained by sol-gel to a process of calcination at 1000 C for 24 hours a curved Tl it presents with two maxim in 185 and in 290 C respectively. The intensity of the response induced in the material it is a decisive factor to continue studying the dosimetric characteristics of the ZrO 2 what allows to consider it as a potential material to use it in the beta particle dosimetry and of the UV light using the thermoluminescence method (Tl). (Author)

  5. Aqueous corrosion behaviour of Zr-1 Nb and Zr-20 Nb with different heat treatments

    Jaime Solis, F.; Bordoni, Roberto; Olmedo, Ana M.; Villegas, Marina; Miyagusuku, Marcela

    2003-01-01

    The corrosion behaviour of Zr-1 Nb and Zr-20 Nb coupons annealed at 850 C degrees during 1 hour and afterwards aged at different temperatures and time periods was studied. The Zr-1 Nb samples were aged at 400 and 500 C degrees and the Zr-20 Nb samples at 265 and 550 C degrees. The results have shown that ageing increases the corrosion resistance because the aged microstructure is somewhat closer to the equilibrium one. This was not the case of Zr-1 Nb aged 72 hs at 400 C degrees. The presence of the ω-phase does not have a deleterious effect in the corrosion behaviour of Zr-20 Nb. Also, an ageing of 2200 h at 265 C degrees induced a relevant decrease in the corrosion rate of Zr-20 Nb indicating a decomposition of the β- Zr phase. This effect was observed at the inlet of pressure tubes in CANDU reactors. The results obtained will be used to establish the relative importance of the α-Zr and β-Zr phases in the corrosion behaviour of pressure tubes. (author)

  6. Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

    Witusiewicz, V.T.; Sommer, F.

    2000-01-01

    Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni 26 Zr 74 . In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys

  7. The morphology and structure of PVD ZrN-Cu thin films

    Audronis, M; Jimenez, O; Leyland, A; Matthews, A

    2009-01-01

    ZrN-Cu thin films containing variable amounts of copper, namely 8, 33 and 58 at%, were produced by reactive pulsed unbalanced magnetron sputtering. Coatings were found to possess hardness values of 22.5 GPa, 9.5 GPa and 3.7 GPa, respectively. The morphology of coatings was investigated by field emission gun scanning electron microscopy and the structure (microstructure and nanostructure) was investigated by conventional (bright-field and dark-field imaging) and high-resolution transmission electron microscopy. Complementary x-ray diffraction experiments were also performed. ZrN coatings containing 8 at% of copper were found to possess a nano-columnar structure composed of ZrN columnar grains, the diameter of which was approximately 15-35 nm. The majority of the copper content was apparently dissolved within the ZrN grains, rather than existing as a separate phase. Coatings of the two other compositions were found to be composed of a mixture of mostly equiaxed ZrN and Cu nano-crystalline grains, the diameters of which were in the approximate range 5-25 nm. None of the coatings investigated in this study were found to possess the so-called 'nanocomposite' structure, which is often envisaged as crystalline nano-grains surrounded by a thin amorphous intergranular phase. Instead, coatings were found to be either single-phase ZrN (with Cu in substitutional solid solution for Zr) or a mixture of ZrN and Cu nano-grains.

  8. Mechanical and thermal properties of bulk ZrB{sub 2}

    Nakamori, Fumihiro [Graduate School of Engineering, Osaka University (Japan); Ohishi, Yuji, E-mail: ohishi@ms.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Fukumoto, Ken-ichi [Research Institute of Nuclear Engineering, University of Fukui (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

    2015-12-15

    ZrB{sub 2} appears to have formed in the fuel debris at the Fukushima Daiichi nuclear disaster site, through the reaction between Zircaloy cladding materials and the control rod material B{sub 4}C. Since ZrB{sub 2} has a high melting point of 3518 K, the ceramic has been widely studied as a heat-resistant material. Although various studies on the thermochemical and thermophysical properties have been performed for ZrB{sub 2}, significant differences exist in the data, possibly due to impurities or the porosity within the studied samples. In the present study, we have prepared a ZrB{sub 2} bulk sample with 93.1% theoretical density by sintering ZrB{sub 2} powder. On this sample, we have comprehensively examined the thermal and mechanical properties of ZrB{sub 2} by the measurement of specific heat, ultrasonic sound velocities, thermal diffusivity, and thermal expansion. Vickers hardness and fracture toughness were also measured and found to be 13–23 GPa and 1.8–2.8 MPa m{sup 0.5}, respectively. The relationships between these properties were carefully examined in the present study. - Highlights: • A ZrB{sub 2} bulk sample with 93.1% theoretical density was prepared by sintering ZrB{sub 2} powder. • We have evaluated mechanical and thermal properties such as Vickers hardness, fracture toughness and thermal conductivity. • The relationships between these properties were carefully examined.

  9. Combinatorial Clustering Algorithm of Quantum-Behaved Particle Swarm Optimization and Cloud Model

    Mi-Yuan Shan

    2013-01-01

    Full Text Available We propose a combinatorial clustering algorithm of cloud model and quantum-behaved particle swarm optimization (COCQPSO to solve the stochastic problem. The algorithm employs a novel probability model as well as a permutation-based local search method. We are setting the parameters of COCQPSO based on the design of experiment. In the comprehensive computational study, we scrutinize the performance of COCQPSO on a set of widely used benchmark instances. By benchmarking combinatorial clustering algorithm with state-of-the-art algorithms, we can show that its performance compares very favorably. The fuzzy combinatorial optimization algorithm of cloud model and quantum-behaved particle swarm optimization (FCOCQPSO in vague sets (IVSs is more expressive than the other fuzzy sets. Finally, numerical examples show the clustering effectiveness of COCQPSO and FCOCQPSO clustering algorithms which are extremely remarkable.

  10. Evolving Models of Pavlovian Conditioning: Cerebellar Cortical Dynamics in Awake Behaving Mice

    Michiel M. ten Brinke

    2015-12-01

    Full Text Available Three decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink responses (CRs. However, trial-by-trial quantification of this link in awake behaving animals is lacking, and current hypotheses regarding the underlying plasticity mechanisms have diverged from the classical parallel fiber one to the Purkinje cell synapse LTD hypothesis. Here, we establish that acquired simple spike suppression, acquired conditioned stimulus (CS-related complex spike responses, and molecular layer interneuron (MLI activity predict the expression of CRs on a trial-by-trial basis using awake behaving mice. Additionally, we show that two independent transgenic mouse mutants with impaired MLI function exhibit motor learning deficits. Our findings suggest multiple cerebellar cortical plasticity mechanisms underlying simple spike suppression, and they implicate the broader involvement of the olivocerebellar module within the interstimulus interval.

  11. Phase equilibria in the Zr-Si-B ternary system (Zr-Si-ZrB{sub 2} region) at 1 173 K

    Han, Feng; Luo, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Lab. of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Lab. of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-10-15

    The isothermal section of the Zr-Si-B ternary system (Zr-Si-ZrB{sub 2} region) at 1 173 K has been experimentally determined. All equilibrated alloys were characterized via X-ray powder diffraction and scanning electron microscopy equipped with energy-dispersive X-ray analysis. A ternary phase Zr{sub 5}(Si{sub 0.86}B{sub 0.14}){sub 3} was found at 1 173 K. The experimental results show that the isothermal section consists of 11 single-phase regions, 26 two-phase regions and 13 three-phase regions. The existence of eight compounds, i.e. ZrSi{sub 2}, ZrSi, Zr{sub 5}Si{sub 4}, Zr{sub 3}Si{sub 2}, Zr{sub 2}Si, ZrB, ZrB{sub 2} and Zr{sub 5}(Si{sub 0.86}B{sub 0.14}){sub 3} in this system has been confirmed in the Zr-Si-ZrB{sub 2} region at 1 173 K.

  12. Extraordinary high strength Ti-Zr-Ta alloys through nanoscaled, dual-cubic spinodal reinforcement.

    Biesiekierski, Arne; Ping, Dehai; Li, Yuncang; Lin, Jixing; Munir, Khurram S; Yamabe-Mitarai, Yoko; Wen, Cuie

    2017-04-15

    While titanium alloys represent the current state-of-the-art for orthopedic biomaterials, concerns still remain over their modulus. Circumventing this via increased porosity requires high elastic admissible strains, yet also limits traditional thermomechanical strengthening techniques. To this end, a novel β-type Ti-Zr-Ta alloy system, comprised of Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta, was designed and characterized mechanically and microstructurally. As-cast, this system displayed extremely high yield strengths and elastic admissible strains, up to 1.4GPa and potentially 1.48%, respectively. This strength was attributed to a nanoscaled, cuboidal structure of semi-coherent, dual body-centered cubic (BCC) phases, arising from the thermodynamics of interaction between Ta and Zr; this morphology occurring with dual BCC-phases is heretofore unreported in Ti-based alloys. Further, cell proliferation investigated by MTS assay suggests this was achieved without sacrificing biocompatibility, with no significant difference to either empty-well or commercially-pure Ti controls noted. The current research details microstructural, mechanical, and biological investigations into four novel biomedical alloys in a hitherto uninvestigated region of the Ti-Zr-Ta alloy system; Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta. We find that the investigated alloys display 0.2% yield strengths of up to 1.40GPa and elastic admissible strains of up to 1.48%, along with biological properties comparable to that seen in the conventional metallic biomaterial ASTM Grade-2 CP-Ti, achieved in the complete absence of traditional thermomechanical processing techniques. This is attributed to the presence of a dual-BCC cuboidal nanostructure, achieved via spinodal decomposition; while similar structures have been reported in e.g. Ni-based superalloys, we believe this is the first such structure investigated in a Ti-based material. As such, this work is felt to be of

  13. Determination of 93Zr in nuclear power plant wastes

    Osváth, Szabolcs; Vajda, Nora; Molnar, Zsuzsa

    2017-01-01

    A radioanalytical method (based on separation using UTEVA columns and ICP-MS measurement) has been used for determination of 93Zr in 37 nuclear power plant samples. As 93Nb might affect the detection of 93Zr, Monte Carlo activation model was used to calculate the expected 93Zr/natZr mass ratio...

  14. Do Students Behave Rationally in Multiple Choice Tests? Evidence from a Field Experiment

    María Paz Espinosa; Javier Gardeazabal

    2013-01-01

    A disadvantage of multiple choice tests is that students have incentives to guess. To discourage guessing, it is common to use scoring rules that either penalize wrong answers or reward omissions. In psychometrics, penalty and reward scoring rules are considered equivalent. However, experimental evidence indicates that students behave differently under penalty or reward scoring rules. These differences have been attributed to the different framing (penalty versus reward). In this paper, we mo...

  15. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT

    Xiaohua Nie

    2017-01-01

    Full Text Available Cat Swarm Optimization (CSO algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO algorithm, the application of CSO is greatly limited by the drawback of “premature convergence,” that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  16. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT.

    Nie, Xiaohua; Wang, Wei; Nie, Haoyao

    2017-01-01

    Cat Swarm Optimization (CSO) algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO) algorithm, the application of CSO is greatly limited by the drawback of "premature convergence," that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO) algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  17. An Adaptive Cultural Algorithm with Improved Quantum-behaved Particle Swarm Optimization for Sonar Image Detection.

    Wang, Xingmei; Hao, Wenqian; Li, Qiming

    2017-12-18

    This paper proposes an adaptive cultural algorithm with improved quantum-behaved particle swarm optimization (ACA-IQPSO) to detect the underwater sonar image. In the population space, to improve searching ability of particles, iterative times and the fitness value of particles are regarded as factors to adaptively adjust the contraction-expansion coefficient of the quantum-behaved particle swarm optimization algorithm (QPSO). The improved quantum-behaved particle swarm optimization algorithm (IQPSO) can make particles adjust their behaviours according to their quality. In the belief space, a new update strategy is adopted to update cultural individuals according to the idea of the update strategy in shuffled frog leaping algorithm (SFLA). Moreover, to enhance the utilization of information in the population space and belief space, accept function and influence function are redesigned in the new communication protocol. The experimental results show that ACA-IQPSO can obtain good clustering centres according to the grey distribution information of underwater sonar images, and accurately complete underwater objects detection. Compared with other algorithms, the proposed ACA-IQPSO has good effectiveness, excellent adaptability, a powerful searching ability and high convergence efficiency. Meanwhile, the experimental results of the benchmark functions can further demonstrate that the proposed ACA-IQPSO has better searching ability, convergence efficiency and stability.

  18. A charged anisotropic well-behaved Adler-Finch-Skea solution satisfying Karmarkar condition

    Bhar, Piyali; Singh, Ksh. Newton; Rahaman, Farook; Pant, Neeraj; Banerjee, Sumita

    In the present paper, we discover a new well-behaved charged anisotropic solution of Einstein-Maxwell’s field equations. We ansatz the metric potential g00 of the form given by Maurya et al. (Eur. Phys. J. C 76(12) (2016) 693) with n = 2. In their paper, it is mentioned that for n = 2, the solution is not well-behaved for neutral configuration as the speed of sound is nondecreasing radially outward. However, the solution can represent a physically possible configuration with the inclusion of some net electric charge, i.e. the solution can become a well-behaved solution with decreasing sound speed radially outward for a charged configuration. Due to the inclusion of electric charge, the solution leads to a very stiff equation-of-state (EoS) with the velocity of sound at the center vr02 = 0.819, vt02 = 0.923 and the compactness parameter u = 0.823 is close to the Buchdahl limit 0.889. This stiff EoS support a compact star configuration of mass 5.418M⊙ and radius of 10.1km.

  19. On the isotope effects of ZrCoX3 (X = H, D and T): a first-principles study

    Chattaraj, D.; Parida, S.C.; Dash, Smruti; Majumder, C.

    2013-01-01

    In the ITER project, the ZrCo-X (X= H, D and T) systems have gained considerable attention because of its use in the hydrogen isotope storage. The isotopic effects on the ZrCoX 3 (X= H, D and T) compounds have been studied in terms of the variation of the thermodynamic parameters using the DFT and frozen phonon approach. A significant difference between the ZrCoH 3 and its isotopic analogues has been noticed in terms of zero point energy (ZPE) and phonon frequencies. The zero point energies are 65.47 kJ/mol, 48.07 kJ/mol and 39.32 kJ/mol for ZrCoH 3 , ZrCoD 3 and ZrCoT 3 , respectively. The enthalpy of formation of ZrCoX 3 compounds, including the ZPE contributions, are -124.84, -142.24 and -150.99 kJ/(mole of compound) for X = H, D and T, respectively. (author)

  20. Microstructure and mechanical properties of ZrO{sub 2} particle dispersion strengthened 16MnV steel

    Wang, B.A. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Wang, N. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); CNOOC Research Institute of Oil and Petrochemicals (CRI), Beijing 100000 (China); Yang, Y.J.; Zhong, H. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, M.Z., E-mail: mz550509@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, X.Y.; Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2017-04-24

    The dispersion strengthened 16MnV steels with 0.5 wt% and 1.2 wt% ZrO{sub 2} particles were prepared using medium frequency induction melting furnace. The ZrO{sub 2} particles mixed with iron powder were added into the 16MnV steel through cored-wire injection process. Optical metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to observe and analyze the microstructure, fracture morphology, dislocation configuration and strengthening mechanism of ZrO{sub 2} particle dispersion strengthened 16MnV steel under as-cast, normalizing and quenching states. Results showed that the strength of 16MnV steel under various states increased significantly after the addition of dispersed ZrO{sub 2} particles. Analysis indicates that the dislocation cell formed by high density dislocation around ZrO{sub 2} particles and attractive interaction between those particles are the main strengthening mechanism of dispersion strengthened 16MnV steel. The tensile test results showed that remarkable strengthening effect of ZrO{sub 2} particle on 16MnV steel has been observed. As the addition of 1.2 wt% ZrO{sub 2}, the improvement of strength in ZrO{sub 2}/16MnV is approximately 37.69% for as-casting, 24.2% after normalization and 29.96% after quenching, respectively. The normalized ZrO{sub 2}/16MnV with 1.2 wt% ZrO{sub 2} has the highest strength of 1453 MPa.

  1. Ab initio hybrid DFT calculations of BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces

    Eglitis, Roberts I., E-mail: rieglitis@gmail.com

    2015-12-15

    Highlights: • Surface energies for AO{sub 3}-term (111) surfaces are larger than for Ti (Zr)-term surfaces. • A increase of Ti−O (Zr−O) bond covalency near the ABO{sub 3} (111) surface relative to the bulk is observed. • The ABO{sub 3} (111) surface energy is larger than the earlier calculated (001) surface energy. • Band gap for PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces becomes smaller, but for BaTiO{sub 3} (111) larger with respect to the bulk . - Abstract: The results of ab initio calculations for polar BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces using the CRYSTAL code are presented. By means of the hybrid B3LYP approach, the surface relaxation has been calculated for two possible B (B = Ti or Zr) or AO{sub 3} (A = Ba, Pb or Sr) BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surface terminations. According to performed B3LYP calculations, all atoms of the first surface layer, for both terminations, relax inwards. The only exception is a small outward relaxation of the PbO{sub 3}-terminated PbTiO{sub 3} (111) surface upper layer Pb atom. B3LYP calculated surface energies for BaO{sub 3}, PbO{sub 3}, SrO{sub 3} and PbO{sub 3}-terminated BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces are considerably larger than the surface energies for Ti (Zr)-terminated (111) surfaces. Performed B3LYP calculations indicate a considerable increase of Ti−O (Zr−O) chemical bond covalency near the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surface relative to the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} bulk. Calculated band gaps at the Γ-point near the PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} (111) surfaces are reduced, but near BaTiO{sub 3} (111) surfaces increased, with respect to the BaTiO{sub 3}, PbTiO{sub 3}, SrZrO{sub 3} and PbZrO{sub 3} bulk band gap at the Γ-point values.

  2. Electronic structure of ZrS{sub x}Se{sub 2-x} by density functional theory

    Ghafari, Ailakbar; Moustafa, Mohamed; Janowitz, Christoph; Dwelk, Helmut; Manzke, Recardo [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Bouchani, Arash [Physics Department, Islamic Azad University, Kermanshah Branch (Iran, Islamic Republic of)

    2011-07-01

    The electronic properties of the ZrS{sub x}Se{sub 2-x} (x varies between zero and two) semiconductors have been calculated by density functional theory (using the Wien2K code) employing the full potential Hamiltonian within the Generalized Gradient Approximation (GGA) method. The results obtained for the end members of the series, i.e. ZrS{sub 2} and ZrSe{sub 2} reveal that the valence band maximum and conduction band minimum are located at {gamma} and between {gamma} and K respectively which is in agreement with our photoemission experimental data. Trends in the electronic structure for the whole substitution series are discussed.

  3. Synthetic of Zr2Al3C5 material

    Leela-Adisorn, U.; Yamaguchi, A.

    2005-01-01

    Synthesis method of Zr 2 Al 3 C 5 via solid state reaction between Al, ZrC and carbon powder was studied. Al-ZrC-C compact with equivalent mol ratio of Zr 2 Al 3 C 5 was heated up to 1600 C in Ar atmosphere for 1 h and 4 h but ZrC phase still existed as major phase with very small amount of Zr 2 Al 3 C 5 . Because ZrC started to oxidize at low temperature under very low oxygen partial pressure, the same mol ratio of Al-ZrC-C compact was heated at 1600 C in vacuum for 1 h as parallel test. After firing in vacuum, some carbon still exist with small amount of AlZrC 2 occurred with Zr 2 Al 3 C 5 as a main phase, but no ZrC was found. Different result from firing in Ar atmosphere and in vacuum had been discussed here. It was believed that very small amount of impurities in Ar had some effect on the formation of Al-Zr-C compound. The effect of very small amount of impurities in Ar was studied by thermal analysis (DTA/TG) and XRD. It was found that very small amount of impurities in Ar has effect on the reaction between Al, ZrC and carbon by diffusion through the surface and form Zr-C-O-N solid solution. This solid solution cannot differentiate from ZrC by XRD. With help of thermal analysis method (DTA/TG), Zr-C-O-N solid solution can be differentiated from ZrC. Therefore, synthesis of Al-Zr-C compound should be done in vacuum. Zr 2 Al 3 C 5 can be prepared from mixture of Al-ZrC-C with excess amount of Al at 1600 C for 1 h. (orig.)

  4. Characterization of gadolinium-doped ZrO{sub 2} films exposed to ultraviolet light; Caracterizacion de peliculas de ZrO{sub 2} dopado con gadolinio expuestas a luz ultravioleta

    Sanchez R, A.; Azorin, J.; Rivera, T. [UAM-I, 09340 Mexico D.F. (Mexico)

    2003-07-01

    This paper presents the results of characterizing gadolinium-doped ZrO{sub 2} (ZrO{sub 2}: Gd) films, both morphological and respect to their optical and thermoluminescent properties after irradiation with ultraviolet (UV) light. ZrO{sub 2} presented crystalline structure in monoclinic phase; its absorption spectrum exhibited a peak at 274 and 277 nm for films deposited on glass and quartz substrates respectively. The optimum concentration of the dopant was found to be 12%. ZrO{sub 2}: Gd presents its maximum Tl response when it is exposed to lJV light of wavelength in the range from 240 to 245 nm; its glow curve shows apparently one peak, which probably is the overlapping of various peaks. (Author)

  5. Zr3NiSb7: a new antimony-enriched ZrSb2 derivative

    V. Romaka

    2008-08-01

    Full Text Available Single crystals of trizirconium nickel heptaantimonide were synthesized from the constituent elements by arc-melting. The compound crystallizes in a unique structure type and belongs to the family of two-layer structures. All crystallographically unique atoms (3 × Zr, 1 × Ni and 7 × Sb are located at sites with m symmetry. The structure contains `Zr2Ni2Sb5' and `Zr4Sb9' fragments and might be described as a new ZrSb2 derivative with a high Sb content.

  6. Experimental investigation of the Zr corner of the ternary Zr-Nb-Fe phase diagram

    Granovsky, M.S. E-mail: granovsk@cnea.gov.ar; Canay, M.; Lena, E.; Arias, D

    2002-04-01

    Intermediate phases in the Zr-rich region of the Zr-Nb-Fe system have been investigated by X-ray diffraction, optical and electron microscopy and electron microprobe analysis. The chemical composition ranges covered by the alloys studied here are: (41-97) at.% Zr, (32-0.9) at.% Nb and (0.6-38) at.% Fe. The phases found in this region were: the solid solutions {alpha}-Zr and {beta}-Zr, the intermetallic Zr{sub 3}Fe with less than 0.2 at.% Nb in solution, two new ternary intermetallic compounds (Zr+Nb){sub 2}Fe '{lambda}{sub 1}' with a cubic Ti{sub 2}Ni-type structure in the composition range (2.4-13) at.% Nb and (31-33) at.% Fe, and (Fe+Nb){sub 2}Zr '{lambda}{sub 2}' indexed as hexagonal Laves phase MgZn{sub 2} type (C14) with a wide range of compositions close to (35-37) at.% Zr, (12-31) at.% Nb and (32-53) at.% Fe.

  7. Experimental investigation of the Zr corner of the ternary Zr-Nb-Fe phase diagram

    Granovsky, M.S.; Canay, M.; Lena, E.; Arias, D.

    2002-01-01

    Intermediate phases in the Zr-rich region of the Zr-Nb-Fe system have been investigated by X-ray diffraction, optical and electron microscopy and electron microprobe analysis. The chemical composition ranges covered by the alloys studied here are: (41-97) at.% Zr, (32-0.9) at.% Nb and (0.6-38) at.% Fe. The phases found in this region were: the solid solutions α-Zr and β-Zr, the intermetallic Zr 3 Fe with less than 0.2 at.% Nb in solution, two new ternary intermetallic compounds (Zr+Nb) 2 Fe 'λ 1 ' with a cubic Ti 2 Ni-type structure in the composition range (2.4-13) at.% Nb and (31-33) at.% Fe, and (Fe+Nb) 2 Zr 'λ 2 ' indexed as hexagonal Laves phase MgZn 2 type (C14) with a wide range of compositions close to (35-37) at.% Zr, (12-31) at.% Nb and (32-53) at.% Fe

  8. Antibacterial activity and cell compatibility of TiZrN, TiZrCN, and TiZr-amorphous carbon coatings

    Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@nfu.edu.tw [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Liu, Jia-Xu [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Tsai, Ming-Tzu [Department of Biomedical Engineering, Hungkuang University, Taichung 433, Taiwan (China); Lai, Chih-Ho [Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan (China)

    2015-12-01

    A cathodic-arc evaporation system with plasma-enhanced duct equipment was used to deposit TiZrN, TiZrCN, and TiZr/a-C coatings. Reactive gases (N{sub 2} and C{sub 2}H{sub 2}) activated by the Ti and Zr plasma in the evaporation process was used to deposit the TiZrCN and TiZr/a-C coatings with different C and nitrogen contents. The crystalline structures and bonding states of coatings were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The microbial activity of the coatings was evaluated against Staphylococcus aureus (Gram-positive bacteria) and Actinobacillus actinomycetemcomitans (Gram-negative bacteria) by in vitro antibacterial analysis using a fluorescence staining method employing SYTO9 and a bacterial-viability test on an agar plate. The cell compatibility and morphology related to CCD-966SK cell-line human skin fibroblast cells on the coated samples were also determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, reverse-transcriptase-polymerase chain reaction, and scanning electron microscopy. The results suggest that the TiZrCN coatings not only possess better antibacterial performance than TiZrN and TiZr/a-C coatings but also maintain good compatibility with human skin fibroblast cells. - Highlights: • TiZrN, TiZrCN, and TiZr/a-C coatings were deposited using cathodic arc evaporation. • The TiZrCN showed a composite structure containing TiN, ZrN, and a-C. • The TiZrCN-coated Ti showed the least hydrophobicity among the samples. • The TiZrCN-coated Ti showed good human skin fibroblast cell viability. • The TiZrCN-coated Ti exhibited good antibacterial performance.

  9. Growth kinetics of tetragonal and monoclinic ZrO2 crystallites in 3 mol% yttria partially stabilized ZrO2 (3Y-PSZ) precursor powder

    Kuo, Chih-Wei; Lee, Kuen-Chan; Yen, Feng-Lin; Shen, Yun-Hwei; Lee, Huey-Er; Wen, Shaw-Bing; Wang, Moo-Chin; Stack, Margaret Mary

    2014-01-01

    Highlights: • The crystalline structures were composed of tetragonal and monoclinic ZrO 2 . • Growth kinetics of t-ZrO 2 in the 3Y-PSZ precursor powder is described as: D te 2 =(4.57±0.55)t 0.12±0.02 exp(-((24.79±0.38)×10 3 )/(RT) ). • Growth kinetics of m-ZrO 2 in the 3Y-PSZ precursor powder is described as: D m 2 =(4.40±1.63)t 0.17±0.08 exp(-((66.47±3.97)×10 3 )/(RT) ). - Abstract: The growth kinetics of tetragonal and monoclinic ZrO 2 crystallites in 3 mol% yttria partially stabilized ZrO 2 (3Y-PSZ) precursor powder has been investigated using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, transmission electron microscopy (TEM) and high resolution TEM (HRTEM). After calcination of the 3Y-PSZ precursor powder between 773 and 1073 K for 2 h, the crystalline structures were composed of tetragonal and monoclinic ZrO 2 as the primary and secondary phases, respectively. When the 3Y-PSZ precursor powder was calcined at 773 K for 2 h, the BET specific surface area was 97.13 m 2 /g, which is equivalent to a particle size of 10.30 nm. The crystallite sizes determined via XRD and BET agreed well, indicating that the powder was virtually non-agglomerated. The growth kinetics of tetragonal and monoclinic ZrO 2 crystallite isothermal growth in the 3Y-PSZ precursor powder are described by: D te 2 =(4.57±0.55)t 0.12±0.02 exp(-((24.79±0.38)×10 3 )/(RT) ) and D m 2 =(4.40±1.63)t 0.17±0.08 exp(-((66.47±3.97)×10 3 )/(RT) ), respectively, for 773K≤T≤1073K. D te and D m denote the crystallite size of tetragonal and monoclinic ZrO 2 at time t and temperature T, respectively

  10. Oxidation of Zr and thin (0.2-4 nm) Zr films on Ag: An ESCA investigation

    Steiner, P.; Sander, I.; Siegwart, B.; Huefner, S.

    1987-01-01

    The oxidation of polycrystalline Zr under 10 -8 -10 -3 mbar oxygen pressure in the temperature range 25 0 -350 0 C is obtained from ESCA experiments. Changes in the ESCA spectra for thin Zr films on Ag oxidized at 250 0 C are observed and compared to the bulk Zr-metal. Thin Ag overlayers on Zr show a catalytic increase of the room temperature oxidation of Zr. (orig.)

  11. Enhancement of wear and corrosion resistance of low modulus β-type Zr-20Nb-xTi (x=0, 3) dental alloys through thermal oxidation treatment.

    Zhang, Jianfeng; Gan, Xiaxia; Tang, Hongqun; Zhan, Yongzhong

    2017-07-01

    In order to obtain material with low elastic modulus, good abrasion resistance and high corrosion stability as screw for dental implant, the biomedical Zr-20Nb and Zr-20Nb-3Ti alloy with low elastic modulus were thermal oxidized respectively at 700°C for 1h and 600°C for 1.25h to obtain the compact oxidized layer to improve its wear resistance and corrosion resistance. The results show that smooth compact oxidized layer (composed of monoclinic ZrO 2 , tetragonal ZrO 2 and 6ZrO 2 -Nb 2 O 5 ) with 22.6μm-43.5μm thickness and 1252-1306HV hardness can be in-situ formed on the surface of the Zr-20Nb-xTi (x=0, 3). The adhesion of oxidized layers to the substrates is determined to be 58.35-66.25N. The oxidized Zr-20Nb-xTi alloys reveal great improvement of the pitting corrosion resistance in comparison with the un-oxidized alloys. In addition, the oxidized Zr-20Nb-3Ti exhibits sharply reduction of the corrosion rates and the oxidized Zr-20Nb shows higher corrosion rates than un-oxidized alloys, which is relevant with the content of the t-ZrO 2 . Wear test in artificial saliva demonstrates that the wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) are superior to pure Ti. All of the un-oxidized Zr-20Nb-xTi (x=0, 3) alloys suffer from serious adhesive wear due to its high plasticity. Because of the protection from compact oxide layer with high adhesion and high hardness, the coefficients of friction and wear losses of the oxidized Zr-20Nb-xTi (x=0, 3) alloys decrease 50% and 95%, respectively. The defects on the oxidized Zr-20Nb have a negative effect on the friction and wear properties. In addition, after the thermal oxidation, compression test show that elastic modulus and strength of Zr-20Nb-xTi (x=0, 3) increase slightly with plastic deformation after 40% of transformation. Furthermore, stripping of the oxidized layer from the alloy matrix did not occur during the whole experiments. As the surface oxidized Zr-20Nb-3Ti alloy has a combination of excellent performance

  12. Ni-ZrB2 electrocomposites

    Pushpavanam, M.; Natarajan, S.R.

    1992-01-01

    New generation materials require high temperature oxidation resistance besides many other tribological properties. Ni-ZrB 2 composites and their properties are dealt with in this paper. (author). 7 refs., 3 figs., 4 tabs

  13. Thermoluminescent dosimetry of beta radiations of {sup 90} Sr/ {sup 90} Y using ZrO{sub 2}: Eu; Dosimetria termoluminiscente de radiaciones beta de {sup 90} Sr/ {sup 90} Y usando ZrO{sub 2}: Eu

    Olvera T, L.; Azorin N, J.; Barrera S, M.; Soto E, A.M. [UAM-I, 09340 Mexico D.F. (Mexico); Rivera M, T. [CICATA-IPN, Legaria 694, 11500 Mexico D.F. (Mexico)

    2005-07-01

    In this work the results of studying the thermoluminescent properties (TL) of the doped zirconium oxide with europium (ZrO{sub 2}: Eu{sup 3+}) before beta radiations of {sup 90}Sr/ {sup 90}Y are presented. The powders of ZrO{sub 2}: Eu{sup 3+} were obtained by means of the sol-gel technique and they were characterized by means of thermal analysis and by X-ray diffraction. The powders of ZrO{sub 2}: Eu{sup 3+}, previously irradiated with beta particles of {sup 90}Sr/ {sup 90}Y, presented a thermoluminescent curve with two peaks at 204 and 292 C respectively. The TL response of the ZrO{sub 2}: Eu{sup 3+} as function of the absorbed dose was lineal from 2 Gy up to 90 Gy. The fading of the information of the ZrO{sub 2}: Eu{sup 3+} was of 10% the first 2 hours remaining almost constant the information by the following 30 days. The ZrO{sub 2} doped with the (Eu{sup 3+}) ion it was found more sensitive to the beta radiation that the one of zirconium oxide without doping (ZrO{sub 2}) obtained by the same method. Those studied characteristics allow to propose to the doped zirconium oxide with europium like thermoluminescent dosemeter for the detection of the beta radiation. (Author)

  14. Hydrogenation of FeCoZr-Al2O3 nanocomposites studied by Moessbauer spectroscopy and magnetometry

    Saad, A.; Kasiuk, J.; Fedotova, J.; Szilagyi, E.; Przewoznik, J.; Kapusta, Cz.; Marszalek, M.

    2009-01-01

    Hydrogenation effects on crystalline and magnetic structure of nanocomposites (FeCoZr) x (Al 2 O 3 ) 100-x , 38 ≤ x ≤ 63 at.% are studied by 57 Fe Moessbauer spectroscopy and magnetometry. Variations of local structure, blocking temperature and mean FeCoZr nanoparticles' volume are discussed with respect to (i) composition and (ii) two competing processes-H 2 incorporation and annealing-occurred during treatment in H 2 plasma.

  15. Optical refractive index and static permittivity of mixed Zr-Si oxide thin films prepared by ion beam induced CVD

    Ferrer, F.J. [Centro Nacional de Aceleradores, Av. Thomas A. Edison, 7, 41092 Sevilla (Spain)], E-mail: fjferrer@us.es; Frutos, F. [E.T.S. de Ingenieria Informatica, Avda. Reina Mercedes, s/n, 41012 Sevilla (Spain); Garcia-Lopez, J. [Centro Nacional de Aceleradores, Av. Thomas A. Edison, 7, 41092 Sevilla (Spain); Gonzalez-Elipe, A.R.; Yubero, F. [Insituto de Ciencia de Materiales de Sevilla, c/ Americo vespucio, no. 49, 41092 Sevilla (Spain)

    2007-12-03

    Mixed oxides Zr{sub x}Si{sub 1-x}O{sub 2} (0 < x < 1) thin films have been prepared at room temperature by decomposition of (CH{sub 3}CH{sub 2}O){sub 3}SiH and Zr[OC(CH{sub 3}){sub 3}]{sub 4} volatile precursors induced by mixtures of O{sub 2}{sup +} and Ar{sup +} ions. The films were flat and amorphous independently of the Si/Zr ratio and did not present phase segregation of the pure single oxides (SiO{sub 2} and ZrO{sub 2}). A 10-23 at.% of H and 1-5 at.% of C atoms remained incorporated in the films depending on the mixture ratio of the Si and Zr precursors and the composition of the bombarding gas used during the deposition process. These impurities are mainly forming hydroxyl and carboxylic groups. Optical refractive index and static permittivity of the films were determined by reflection NIR-Vis spectroscopy and C-V electrical characterization, respectively. It is found that the refractive index increases non-linearly from 1.45 to 2.10 as the Zr content in the thin films increases. The static permittivity also increases non-linearly from {approx} 4 for pure SiO{sub 2} to {approx} 15 for pure ZrO{sub 2}. Optical and electrical characteristics of the films are justified by their impurity content and the available theories.

  16. Plastic Deformation Induced by Nanoindentation Test Applied on ZrN/Si3N4 Multilayer Coatings

    Zhengtao Wu

    2017-12-01

    Full Text Available ZrN/Si3N4 multilayer coating that alternates with either nanocrystalline ZrN or amorphous Si3N4 interlayers was fabricated by reactively magnetron sputtering in an Ar-N2 mixture atmosphere. The thicknesses of the nanocrystalline ZrN and the amorphous Si3N4 interlayers are ~12.5 and 2.5 nm, respectively. The ZrN/Si3N4 coating exhibits a promoted hardness of 28.6 ± 1.2 GPa when compared to the binary ZrN. Microstructure evolution just underneath the nanoindentation impression of the ZrN/Si3N4 multilayer coating has been investigated. The result indicates that both ZrN nanograin rotations and plastic flow of the Si3N4 interlayers contribute to the permanent deformation of the multilayer coating induced by the nanoindentation. In addition, the introduction of the a-Si3N4 interlayers hinders both the initiation and propagation of microcracks when the multilayer coating was applied to the scratch test. The propagation deflection of the microcracks was observed attributed to the heterogenous interface, which produces the hardness promotion of the multilayer coating eventually.

  17. Microstructures and mechanical properties of grain refined Al-Li-Mg casting alloy by containing Zr and Ti

    Saikawa, Seiji; Nakai, Kiyoshi; Sugiura, Yasuo; Kamio, Akihiko.

    1995-01-01

    Mechanical properties and microstructures of various Al-Li-Mg alloy castings containing small amount of Zr and/or Ti were investigated. The δ(AlLi) phase was observed to crystallize in the dendrite-cell gaps as well as on the grain boundaries. Microsegregation of Mg also occurred in the solidified castings. The β(Al 3 Zr) or Al-Zr-Ti compounds crystallize during solidification and remain even after solid solution treatment at 803 K for 36 ks. The grain sizes of Al-2.5%Li-2%Mg alloy castings become finer by the addition of 0.15%Zr and 0.12%Ti compared with each addition of 0.15%Zr or 0.12%Ti. The age hardening is accelerated by the addition of 0.15%Zr. In an Al-2.5%Li-2%Mg-0.15%Zr-0.12%Ti alloy casting poured into a metallic mold and aged at 453 K for 36 ks, ultimate tensile strength, Young's modulus and density were 417 MPa, 80 GPa and was 2.52 g/cm 3 , respectively. Its specific strength and modulus are higher by 50.3 and 13.9% than those of the conventional AC4C-T6 casting. (author)

  18. Lifetime measurements of the first 2+ states in 104,106Zr: Evolution of ground-state deformations

    F. Browne

    2015-11-01

    Full Text Available The first fast-timing measurements from nuclides produced via the in-flight fission mechanism are reported. The lifetimes of the first 2+ states in 104,106Zr nuclei have been measured via β-delayed γ-ray timing of stopped radioactive isotope beams. An improved precision for the lifetime of the 21+ state in 104Zr was obtained, τ(21+=2.90−20+25 ns, as well as a first measurement of the 21+ state in 106Zr, τ(21+=2.60−15+20 ns, with corresponding reduced transition probabilities of B(E2;21+→0g.s.+=0.39(2 e2b2 and 0.31(1 e2b2, respectively. Comparisons of the extracted ground-state deformations, β2=0.39(1 (104Zr and β2=0.36(1 (106Zr with model calculations indicate a persistence of prolate deformation. The data show that 104Zr is the most deformed of the neutron-rich Zr isotopes measured so far.

  19. Reduction behaviors of Zr for LiCl-KCl-ZrCl4 and LiCl-KCl-ZrCl4-CdCl2

    Kim, Si Hyung; Yoon, Jongho; Kim, Gha Young; Kim, Tack Jin; Shim, Joon Bo; Kim, Kwang Rag; Jung, Jae Hoo; Ahn, Do Hee; Paek, Seungwoo

    2013-01-01

    The reduction potentials of most of the zirconium ions on the solid cathode are smaller (about 0.4V) than that of uranium, and thus zirconium can be recovered prior to uranium during the reduction stage. In the case of a liquid cadmium cathode, which is one of the major cathodes, the reduction potential can be changed because zirconium reacts with the liquid cadmium. Up to now, it has not been well known what the reduction potential of Zr was on the liquid Cd cathode. According to the Cd-Zr phase diagram, there are four intermetallic compounds between cadmium and zirconium. It is easier to use the solid cathode than the liquid cadmium cathode in LiCl-KCl-ZrCl 4 containing CdCl 2 to identify the formation of the Cd-Zr phase. In this study, the reduction behaviors of zirconium were compared in the LiCl-KCl-ZrCl 4 and LiCl-KCl-ZrCl 4 -CdCl 2 solutions when using a solid cathode. The reduction behavior of Zr at a solid W cathode and a Cd-coated W cathode was compared in a LiCl-KCl-ZrCl 4 solution at 500 .deg. C. It was observed from the results using a solid W cathode that Zr 4+ ions were gradually oxidized to Zr 2+ , Zr, and ZrCl during the reduction sweep, but the final oxidation peak of Zr 2+ to Zr 4+ seemed to be unclear during the oxidation sweep. In the case of the Cd-coated W electrode, only a Cd 2 Zr phase was formed at 500 .deg. C, which seemed to be related to the melting point of Cd-Zr intermetallics. Through additional studies at different temperatures, the formation behavior will be studied

  20. Solving Bilevel Multiobjective Programming Problem by Elite Quantum Behaved Particle Swarm Optimization

    Tao Zhang

    2012-01-01

    Full Text Available An elite quantum behaved particle swarm optimization (EQPSO algorithm is proposed, in which an elite strategy is exerted for the global best particle to prevent premature convergence of the swarm. The EQPSO algorithm is employed for solving bilevel multiobjective programming problem (BLMPP in this study, which has never been reported in other literatures. Finally, we use eight different test problems to measure and evaluate the proposed algorithm, including low dimension and high dimension BLMPPs, as well as attempt to solve the BLMPPs whose theoretical Pareto optimal front is not known. The experimental results show that the proposed algorithm is a feasible and efficient method for solving BLMPPs.

  1. A simple miniature device for wireless stimulation of neural circuits in small behaving animals.

    Zhang, Yisi; Langford, Bruce; Kozhevnikov, Alexay

    2011-10-30

    The use of wireless neural stimulation devices offers significant advantages for neural stimulation experiments in behaving animals. We demonstrate a simple, low-cost and extremely lightweight wireless neural stimulation device which is made from off-the-shelf components. The device has low power consumption and does not require a high-power RF preamplifier. Neural stimulation can be carried out in either a voltage source mode or a current source mode. Using the device, we carry out wireless stimulation in the premotor brain area HVC of a songbird and demonstrate that such stimulation causes rapid perturbations of the acoustic structure of the song. Published by Elsevier B.V.

  2. Pareto-Ranking Based Quantum-Behaved Particle Swarm Optimization for Multiobjective Optimization

    Na Tian

    2015-01-01

    Full Text Available A study on pareto-ranking based quantum-behaved particle swarm optimization (QPSO for multiobjective optimization problems is presented in this paper. During the iteration, an external repository is maintained to remember the nondominated solutions, from which the global best position is chosen. The comparison between different elitist selection strategies (preference order, sigma value, and random selection is performed on four benchmark functions and two metrics. The results demonstrate that QPSO with preference order has comparative performance with sigma value according to different number of objectives. Finally, QPSO with sigma value is applied to solve multiobjective flexible job-shop scheduling problems.

  3. A novel fiber-free technique for brain activity imaging in multiple freely behaving mice

    Inagaki, Shigenori; Agetsuma, Masakazu; Nagai, Takeharu

    2018-02-01

    Brain functions and related psychiatric disorders have been investigated by recording electrophysiological field potential. When recording it, a conventional method requires fiber-based apparatus connected to the brain, which however hampers the simultaneous measurement in multiple animals (e.g. by a tangle of fibers). Here, we propose a fiber-free recording technique in conjunction with a ratiometric bioluminescent voltage indicator. Our method allows investigation of electrophysiological filed potential dynamics in multiple freely behaving animals simultaneously over a long time period. Therefore, this fiber-free technique opens up the way to investigate a new mechanism of brain function that governs social behaviors and animal-to-animal interaction.

  4. Structural study of Zr-based metallic glasses

    Matsubara, E. [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan)]. E-mail: e.matsubara@materials.mbox.media.kyoto-u.ac.jp; Ichitsubo, T. [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Saida, J. [Center of Interdisciplinary Research, Tohoku University, Sendai 980-8578 (Japan); Kohara, S. [JASRI, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan); Ohsumi, H. [JASRI, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan)

    2007-05-31

    Structures of Zr{sub 70}Ni{sub 20}Al{sub 10}, Zr{sub 70}Cu{sub 20}Al{sub 10}, Zr{sub 70}Cu{sub 30} and Zr{sub 70}Ni{sub 30} amorphous alloys were analyzed by high-energy X-ray diffraction. The relatively stable Zr{sub 2}Cu amorphous alloy shows a local atom arrangement different from the Zr{sub 2}Cu crystalline phase. By contrast, the less stable Zr{sub 70}Ni{sub 30} amorphous alloy has a structure similar to Zr{sub 2}Ni. In the Zr{sub 70}Cu{sub 20}Al{sub 10} metallic glass, Zr-Al nearest neighbor pairs are introduced in the amorphous structure. In the Zr{sub 70}Ni{sub 20}Al{sub 10} metallic glass, the strong correlation between Zr-Ni pairs is drastically modified by the formation of Zr-Al pairs. The presence of Zr-Al pairs in the ternary alloys suppresses the crystallization and stabilizes the glassy state.

  5. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO_2-ZrO_2 nanocomposite

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-01-01

    TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X –ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I – V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO_2, TiO_2-ZrO_2 and Zn doped TiO_2-ZrO_2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  6. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO2-ZrO2 nanocomposite

    Tomar, Laxmi J.; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J.

    2016-05-01

    TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X -ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I - V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO2, TiO2-ZrO2 and Zn doped TiO2-ZrO2 nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  7. Ti and Zr surfaces studied by molecular dynamics

    Pascuet, Maria I.; Passianot, Roberto C.; Monti, Ana M.

    2003-01-01

    The interaction between point defects technique and the (0001), (1-210), (10-10) surfaces in Ti and Zr is studied by the molecular dynamics technique. Both of metals are in the hexagonal structure and within a temperature range of 100 to 900 K. The atomic interactions are modeled by EAM-type many-body potentials, that were used previously in static simulations. New migration mechanisms are unraveled and others are verified with respect to those already proposed in the static studies. Also included is an analysis of the vacancy stability in the sub-surface layers of the prismatic surfaces. (author)

  8. Encapsulation of Mg-Zr alloy in metakaolin-based geo-polymer

    Rooses, Adrien; Steins, Prune; Dannoux-Papin, Adeline; Lambertin, David; Poulesquen, Arnaud; Frizon, Fabien

    2013-01-01

    Investigations were carried out to propose a suitable material for the encapsulation of Mg-Zr alloy wastes issued from fuel cladding of the first generation nuclear reactors. Stability over time, good mechanical properties and low gas production are the main requirements that embedding matrices must comply with in order to be suitable for long run storage. One of the main issues encapsulating Mg-Zr alloy in mineral binder is the hydrogen production related to Mg-Zr alloys corrosion and water radiolysis process. In this context, metakaolin geo-polymers offer an interesting outlook: corrosion densities of Mg-Zr alloys are significantly lower than in Portland cement. This work firstly presents the hydrogen production of Mg-Zr alloy embedded in geo-polymers prepared from different the activation solution (NaOH or KOH). The effect of addition of fluorine on the magnesium corrosion in geo-polymer has been investigated too. The results point out that sodium geo-polymer is a suitable binder for Mg-Zr alloy encapsulation with respect to magnesium corrosion resistance. Furthermore the presence of fluorine reduces significantly the hydrogen release. Then, the impact of fluorine on the geo-polymer network formation was studied by rheological, calorimetric and 19 F NMR measurements. No direct effect resulting from the addition of fluorine has been shown on the geo-polymer binder. Secondly, the formulation of the encapsulation matrix has been adjusted to fulfil the expected physical and mechanical properties. Observations, dimensional evolutions and compressive strengths demonstrated that addition of sand to the geo-polymer binder is efficient to meet the storage criteria. Consequently, a matrix formulation compatible with Mg-Zr alloy encapsulation has been proposed. Finally, irradiation tests have been carried out to assess the hydrogen radiolytic yield of the matrix under exposure to γ radiation. (authors)

  9. Moessbauer and transport studies of amorphous and icosahedral Zr-Ni-Cu-Ag-Al alloys

    Stadnik, Z.M.; Rapp, O.; Srinivas, V.; Saida, J.; Inoue, A.

    2002-01-01

    The alloy Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 in the amorphous and icosahedral states, and the bulk amorphous alloy Zr 65 Al 7.5 Ni 10 Cu 7.5 Ag 10 , have been studied with 57 Fe Moessbauer spectroscopy, electrical resistance and magnetoresistance techniques. The average quadrupole splitting in both alloys decreases with temperature as T 3/2 . The average quadrupole splitting in the icosahedral alloy is the largest ever reported for a metallic system. The lattice vibrations of the Fe atoms in the amorphous and icosahedral alloys are well described by a simple Debye model, with the characteristic Moessbauer temperatures of 379(29) and 439(28) K, respectively. Amorphous alloys Zr 65 Al 7. )5Ni 10 Cu 7.5 Ag 10 and Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 have been found to be superconducting with the transition temperature, T c , of about 1.7 K. The magnitude of Tc and the critical field slope at Tc are in agreement with previous work on Zr-based amorphous superconductors, while the low-temperature normal state resistivity is larger than typical results for binary and ternary Zr-based alloys. The resistivity of icosahedral Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 is larger than that for the amorphous ribbon of the same composition, as inferred both from direct measurements on the ribbons and from the observed magnetoresistance. However the icosahedral sample is non-superconducting in the measurement range down to 1.5 K. The results for the resistivity and the superconducting T c both suggest a stronger electronic disorder in the icosahedral phase than in the amorphous phase. (author)

  10. Investigation of nanostructured Al-10 wt.% Zr material prepared by ball milling for high temperature applications

    Prosviryakov, A.S., E-mail: pro.alex@mail.ru; Shcherbachev, K.D.; Tabachkova, N.Yu.

    2017-01-15

    Ground chips of as-cast Al-10 wt.% Zr alloy were subjected to mechanical alloying (MA) with 5 vol.% of nanodiamond addition in a high energy planetary ball-mill. The aim of this work was to investigate the microstructure, phase transformation and mechanical properties of the material both after MA and after subsequent annealing. Optical and transmission electron microscopes were used for morphological and microstructural analysis. The effect of milling time on powder microhardness, Al lattice parameter, lattice microstrain and crystallite size was determined. It was shown that mechanical alloying of as-cast Al-10wt.%Zr alloy during 20 h leads to a complete dissolution of the primary tetragonal Al{sub 3}Zr crystals in aluminum. At the same time, the powder microhardness increases to 370 HV. Metastable cubic Al{sub 3}Zr phase nanoparticles precipitate from the Al solution due to its decomposition after annealing, however, the Al solid solution remains supersaturated and nanocrystalline. Compression tests at room temperature and at 300 °C showed that the strength values of the hot-pressed samples reach 822 MPa and 344 MPa, respectively. - Highlights: •As-cast Al-10 wt.% Zr alloy was mechanically alloyed with 5 vol.% nanodiamond. •The primary tetragonal Al{sub 3}Zr crystals were completely dissolved in Al after 20 h. •Cubic Al{sub 3}Zr phase nanoparticles precipitated from Al solution after aging. •The aged bulk material showed a high strength at room and elevated temperatures.

  11. Study of oxidation behaviour of Zr-based bulk amorphous alloy Zr 65 ...

    The oxidation behaviour of Zr-based bulk amorphous alloy Zr65Cu17.5Ni10Al7.5 has been studied in air environment at various temperatures in the temperature range 591–684 K using a thermogravimetric analyser (TGA). The oxidation kinetics of the alloy in the amorphous phase obeys the parabolic rate law for oxidation ...

  12. Effect of Mn doping on the structural and optical properties of ZrO2 thin films prepared by sol–gel method

    Berlin, I. John; Lekshmy, S. Sujatha; Ganesan, V.; Thomas, P.V.; Joy, K.

    2014-01-01

    Homogeneous and transparent Mn doped ZrO 2 thin films were prepared by sol–gel dip coating method. The films were annealed in air atmosphere at 500 °C. The X-ray diffraction pattern of the undoped ZrO 2 thin film revealed a mixed phase of tetragonal and monoclinic ZrO 2 with preferred orientations along T(111) and M(− 111). Grazing Incidence X-ray Diffraction of Mn doped ZrO 2 thin films reveals the introduction of Mn interstitial in ZrO 2 which stabilize the mixed phase of ZrO 2 into tetragonal phase. Atomic force microscope image shows the addition of catalyst (Mn) which stops isotropic agglomeration of particles, instead of anisotropic agglomeration that occurred resulting in growth of particles in certain direction. Average transmittances of > 70% (in UV–vis region) were observed for all samples. The optical band gap decreased from 5.72 to 4.52 eV with increase in Mn doping concentration. The reduced band gap is due to the introduction of impurity levels in the band gap, by incorporation of the metal ions into the ZrO 2 lattice. The d-electron of Mn (t 2g level) can easily overlap with the ZrO 2 's valence band (VB) because t 2g of Mn is very close to VB of ZrO 2 . This overlap caused a wide VB and consequently decreases the band gap of ZrO 2 . The photoluminescence (PL) spectrum of undoped zirconia thin film exhibits an intense near band edge emission peak at 392.5 nm (3.15 eV) and weak emission peaks at 304 (4.07 eV), 604 nm (2.05 eV) and 766 nm (1.61 eV). Additional PL peaks were observed for Mn doped ZrO 2 located at around 420, 447 (blue), 483 (blue) and 529 (green) nm respectively. These peaks were due to the redox properties of various valence state of Mn in ZrO 2 . The prepared Mn doped ZrO 2 thin films can be applied in optical devices. - Highlights: • Mn-doped ZrO 2 thin films were prepared by sol–gel dip coating method. • Introduction of Mn interstitial in ZrO 2 stabilizes ZrO 2 into tetragonal phase. • The optical band gap

  13. First principles and phonon calculations of ZrCo and ZrCo-H systems

    Chattaraj, D.; Parida, S.C.; Dash, Smruti; Majumder, C.

    2012-01-01

    The intermetallic ZrCo is a potential material for the storage and release of hydrogen isotopes because of its high gravimetric capacity and its low hydrogen equilibrium pressure. This intermetallic is a proposed material for the safe storage, supply and delivery of hydrogen isotope in the ITER project. To investigate the suitability of ZrCo as a getter material for the storage of hydrogen isotope it is essential to know in detail the structure-property relationships in both ZrCo and its hydride. Hence, in this study, we have investigated the structural, electronic, vibrational and thermodynamic properties of ZrCo and ZrCoH 3 using the first principles and phonon calculations

  14. Flexible Coupling of Respiration and Vocalizations with Locomotion and Head Movements in the Freely Behaving Rat

    Joseph Andrews Alves

    2016-01-01

    Full Text Available Quadrupedal mammals typically synchronize their respiration with body movements during rhythmic locomotion. In the rat, fast respiration is coupled to head movements during sniffing behavior, but whether respiration is entrained by stride dynamics is not known. We recorded intranasal pressure, head acceleration, instantaneous speed, and ultrasonic vocalizations from male and female adult rats while freely behaving in a social environment. We used high-speed video recordings of stride to understand how head acceleration signals relate to locomotion and developed techniques to identify episodes of sniffing, walking, trotting, and galloping from the recorded variables. Quantitative analysis of synchrony between respiration and head acceleration rhythms revealed that respiration and locomotion movements were coordinated but with a weaker coupling than expected from previous work in other mammals. We have recently shown that rats behaving in social settings produce high rates of ultrasonic vocalizations during locomotion bouts. Accordingly, rats emitted vocalizations in over half of the respiratory cycles during fast displacements. We present evidence suggesting that emission of these calls disrupts the entrainment of respiration by stride. The coupling between these two variables is thus flexible, such that it can be overridden by other behavioral demands.

  15. The games economists play: Why economics students behave more selfishly than other students.

    Philipp Gerlach

    Full Text Available Do economics students behave more selfishly than other students? Experiments involving monetary allocations suggest so. This article investigates the underlying motives for the economic students' more selfish behavior by separating three potential explanatory mechanisms: economics students are less concerned with fairness when making allocation decisions; have a different notion of what is fair in allocations; or are more skeptical about other people's allocations, which in turn makes them less willing to comply with a shared fairness norm. The three mechanisms were tested by inviting students from various disciplines to participate in a relatively novel experimental game and asking all participants to give reasons for their choices. Compared with students of other disciplines, economics students were about equally likely to mention fairness in their comments; had a similar notion of what was fair in the situation; however, they expected lower offers, made lower offers, and were less willing to enforce compliance with a fair allocation at a cost to themselves. The economics students' lower expectations mediated their allocation decisions, suggesting that economics students behaved more selfishly because they expected others not to comply with the shared fairness norm.

  16. An Improved Quantum-Behaved Particle Swarm Optimization Algorithm with Elitist Breeding for Unconstrained Optimization.

    Yang, Zhen-Lun; Wu, Angus; Min, Hua-Qing

    2015-01-01

    An improved quantum-behaved particle swarm optimization with elitist breeding (EB-QPSO) for unconstrained optimization is presented and empirically studied in this paper. In EB-QPSO, the novel elitist breeding strategy acts on the elitists of the swarm to escape from the likely local optima and guide the swarm to perform more efficient search. During the iterative optimization process of EB-QPSO, when criteria met, the personal best of each particle and the global best of the swarm are used to generate new diverse individuals through the transposon operators. The new generated individuals with better fitness are selected to be the new personal best particles and global best particle to guide the swarm for further solution exploration. A comprehensive simulation study is conducted on a set of twelve benchmark functions. Compared with five state-of-the-art quantum-behaved particle swarm optimization algorithms, the proposed EB-QPSO performs more competitively in all of the benchmark functions in terms of better global search capability and faster convergence rate.

  17. A portable telemetry system for brain stimulation and neuronal activity recording in freely behaving small animals.

    Ye, Xuesong; Wang, Peng; Liu, Jun; Zhang, Shaomin; Jiang, Jun; Wang, Qingbo; Chen, Weidong; Zheng, Xiaoxiang

    2008-09-30

    A portable multi-channel telemetry system which can be used for brain stimulation and neuronal activity recording in freely behaving small animals is described here. This system consists of three major components of headstage, backpack and portable Personal Digital Assistant (PDA). The headstage contains high precision instrument amplifiers with high input impedance. The backpack is comprised of two parts: (1) a main board (size: 36 mm x 22 mm x 3.5 mm and weight: 40 g with batteries, 20 g without), with current/voltage stimulator and special circuit suitable for neuronal activity recording and (2) and a bluetooth transceiver, with a high data transmission rate up to 70 kb/s, suitable for downloading stimulation commands and uploading acquired data. We recorded neuronal activities of the primary motor area of a freely behaving rat with 12-bit resolution at 12 k samples/s. The recorded data and analysis results showed that the system was successful by comparing with the commercial equipment Cerebus 128-Channel Data Acquisition System (Cyberkinetics Inc.). Using the PDA, we can control stimulation and recording. It provides a flexible method to do some research work in the circumstances where other approaches would be difficult or impossible.

  18. Electrochemical characterization of pulsed layer deposited hydroxyapatite-zirconia layers on Ti-21Nb-15Ta-6Zr alloy for biomedical application

    Izquierdo, Javier [Department of Chemistry, Universidad de La Laguna, P.O. Box 456, E-38200 La Laguna, Tenerife (Spain); Bolat, Georgiana [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 Prof. Dr. Doc. D. Mangeron Street, 700050 Iasi (Romania); Cimpoesu, Nicanor [“Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science, 61-63 Prof. Dr. Doc. D. Mangeron Street, 700050 Iasi (Romania); Trinca, Lucia Carmen [Science Department, University of Agricultural Sciences and Veterinary Medicine, M. Sadoveanu Alley 3, 700490 Iasi (Romania); Mareci, Daniel, E-mail: danmareci@yahoo.com [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 Prof. Dr. Doc. D. Mangeron Street, 700050 Iasi (Romania); Souto, Ricardo Manuel, E-mail: rsouto@ull.es [Department of Chemistry, Universidad de La Laguna, P.O. Box 456, E-38200 La Laguna, Tenerife (Spain); Institute of Material Science and Nanotechnology, Universidad de La Laguna, E-38200 La Laguna, Tenerife (Spain)

    2016-11-01

    Highlights: • New quarternary Ti-based alloy for biomaterial application. • Combined hydroxyapatite-zirconia coating produced by pulsed laser deposition. • Porous layer formed on the coated alloy blocks electron transfer reactions. • Electrochemical behaviour consistent with passive film with duplex structure. • HA–ZrO{sub 2} coated Ti-21Nb-15Ta-6Zr exhibits high potential for osseointegration. - Abstract: A new titanium base Ti-21Nb-15Ta-6Zr alloy covered with hydroxyapatite-zirconia (HA–ZrO{sub 2}) by pulsed laser deposition (PLD) technique was characterized regarding its corrosion resistance in simulated physiological Ringer’s solution at 37 °C. For the sake of comparison, Ti-6Al-4V standard implant alloy, with and without hydroxyapatite-zirconia coating, was also characterized. Multiscale electrochemical analysis using both conventional averaging electrochemical techniques, namely electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization, and spatially-resolved microelectrochemical techniques (scanning electrochemical microscopy, SECM) were used to investigate the electrochemical behaviour of the materials. In addition, scanning electron microscopy evidenced that no relevant surface morphology changes occurred on the materials upon immersion in the simulated physiological solution, despite variations in their electrochemical behaviour. Although uncoated metals appear to show better performances during conventional corrosion tests, the response is still quite similar for the HA–ZrO{sub 2} coated materials while providing superior resistance towards electron transfer due to the formation of a more dense film on the surface, thus effectively behaving as a passive material. It is believed corrosion of the HA–ZrO{sub 2} coated Ti-21Nb-15Ta-6Zr alloy will have negligible effect upon biochemical and cellular events at the bone-implant interface and could facilitate osseointegration.

  19. Oxide layers of Zr-1% Nb under PWR primary circuit conditions

    Nagy, Gabor; Kerner, Zsolt; Battistig, Gabor; Pinter-Csordas, Anna; Balogh, Janos; Pajkossy, Tamas

    2001-01-01

    Oxide layers were grown on Zr-1% Nb under conditions simulating those in VVER-type pressurised water reactors (PWRs), viz. in borate solutions in an autoclave at 290 deg. C. The layers were characterised by various methods: their respective thickness values were determined by weight gain measurements, Rutherford backscattering (RBS), nuclear reaction analysis (NRA) and scanning electron microscopy (SEM); the electrical properties were tested by electrochemical impedance spectroscopy. The results show that the oxide layer on Zr-1% Nb is homogeneous and somewhat thicker than that on Zircaloy-4

  20. 15N NMR studies of layered nitride superconductor LixZrNCl

    Tou, H.; Oshiro, S.; Kotegawa, H.; Taguchi, Y.; Kishiume, Y.; Kasahara, Y.; Iwasa, Y.

    2010-01-01

    NMR measurements were carried out on pristine ZrNCl and Li x ZrNCl. From the 15 N-Knight shift study, the isotropic Knight shift, the traceless chemical (orbital) shift tensor and the traceless Knight shift tensor were determined as K iso = -71 ppm, (σ 1 , σ 2 , σ 3 ) = (-55, -55, 110) ppm and (K 1 , K 2 , K 3 ) = (48, 48, -96) ppm, respectively. In the superconducting state, the fractional change of the 15 N NMR shift for H-parallel ab was observed, evidencing that the pairing symmetry is a spin-singlet state.

  1. X-ray dosimetry of low energy using ZrO2 in Mammography

    Palacios P, L.L.; Rivera M, T.; Ortiz C, H.; Guzman, G.; Azorin, J.; Garcia H, M.

    2008-01-01

    This work reports the experimental results of the thermoluminescent dosemeters (DTL) of nano particles of zirconium dioxide (ZrO 2 ), prepared by the precipitation for X rays method of low energy that are used in mammography equipment. It is observed that the response of the TL curve for X rays of low energy coincides with the TL curve of ZrO 2 reported for conventional X rays. This curve presents two peaks, at 160 and 270 C respectively, being that of more intensity the second peak. (Author)

  2. Preparation and Performance of ZrC Woodceramics Obtained byPolymer Precursor Conversion%先驱体转化法制备ZrC木质陶瓷及其性能分析

    武海棠; 郑冀鲁; 张军华; 黄晓华

    2016-01-01

    以松木为原料,经炭化制得松木炭,以有机锆聚合物(PZC)为先驱体浸渍松木炭后进一步高温热处理制备得到ZrC木质陶瓷.采用XRD、SEM、FT-IR、TG-DSC分别对样品的物相变化、组成和微观结构进行了表征,研究了热处理温度和杂化材料质量增加率对木质陶瓷显气孔率与力学性能的影响.结果表明:有机锆先驱体裂解过程中生成ZrO2,进一步可以在1 400 ℃通过碳热还原反应转化为ZrC相.ZrC木质陶瓷由立方相ZrC和无定形碳组成,生成的木质陶瓷较好地保留了松木模板的管状孔洞结构,部分ZrC相沉积在孔洞内部.木质陶瓷材料显气孔率随着热处理温度的升高而升高,随质量增加率的增加而降低;力学性能随热处理温度和质量增加率的增加而提高,质量增加率为278%的杂化材料在热处理温度为1 400 ℃时制备的ZrC木质陶瓷具有良好的力学性能,弯曲强度和断裂韧性分别为158 MPa和1.8 MPa·m1/2.%Biomorphic ZrC woodceramics were fabricated by high temperature pyrolysis of the precursor of infiltrated organic zirconium-contained polymer(PZC) using pine charcoal as template under argon.The phase change, composition and microstructure of resulting ZrC woodceramics, as well as the conversion mechanism of wood to ZrC woodceramics, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques, respectively.The effects of heat treatment temperature and weight gain of charcoal/PZC hybrid material on the apparent porosity and mechanical properties of the ZrC woodceramics were analysed.The results indicated that the impregnant was firstly decomposed to ZrO2, and then reacted with carbon in the cellular wall to form ZrC at 1 400 ℃.The cellular morphology of biocarbon template was retained well in the resulting ceramics consisting of cubic Zr

  3. H and D implantation transforms Ti, Zr and Hf into good superconductors

    Meyer, J.D.; Stritzker, B.

    1981-01-01

    The elements Ti, Zr, and Hf from group IVB with superconducting transition temperatures of Tsub(c) = 0.4, 0.6 and 0.13 K, respectively, were implanted at liquid helium temperature with hydrogen, deuterium and helium. The He implantations were performed to simulate the Tsub(c) enhancement due to lattice disorder introduced during the implantation. In this case, only Zr showed a Tsub(c) increase above the measuring limit of 1 K. On the other hand, the implantation of H and D will change the electronic properties of the materials in addition to lattice damage. Indeed all H and D implantations lead to a substantial increase of Tsub(c). For example, a transition temperature of 4.65 K was achieved in D implanted Zr at a concentration of D/Zr = 0.13. Whereas a pronounced inverse isotope effects was observed for H(D) implanted Zr and Hf, H and D implanted Ti had essentially the same Tsub(c) of 4.9 K. Based on the similarity of most of these results to the Pd-H(D) system [1], similar mechanisms are proposed to explain the experimental observation, i.e: (1) the electron-phonon coupling is enhanced due to coupling to the protons (deuterons) and/or to the optic phonon modes; (2) anharmonic effects are responsible for the inverse isotope effect. (orig.)

  4. Feasibility study on the application of carbide (ZrC, SiC) for VHTR

    Park, Ji Yeon; Kim, Weon Ju; Jung, Choong Hwan; Ryu, Woo Seog; Kim, Si Hyeong; Jang, Moon Hee; Lee, Young Woo

    2006-08-15

    A feasibility study on the coating process of ZrC for the TRISO nuclear fuel and applications of SiC as high temperature materials for the core components has performed to develop the fabrication process for the advanced ZrC TRISO fuels and the high temperature structural components for VHTR, respectively. In the case of ZrC coating, studies were focused on the comparisons of the developed coating processes for screening of our technology, the evaluations of the reactions parameters for a ZrC deposition by the thermodynamic calculations and the preliminary coating experiments by the chloride process. With relate to SiC ceramics, our interesting items are as followings; an analysis of applications and specifications of the SiC components and collections of the SiC properties and establishments of data base. For these purposes, applications of SiC ceramics for the GEN-IV related components as well as the fusion reactor related ones were reviewed. Additionally, the on-going activities with related to the ZrC clad and the SiC composites discussed in the VHTR GIF-PMB, were reviewed to make the further research plans at the section 1 in chapter 3.

  5. Determination of 93Zr in medium and low level radioactive wastes from Brazilian nuclear power plants

    Oliveira, Thiago C.; Oliveira, Arno H.

    2015-01-01

    The majority of long-lived radionuclides produced in the nuclear power plants can be regarded as difficult-to-measure radionuclides (RDM), hence chemical separation is necessary before the nuclear measurement of them. The zirconium isotope 93 Zr is a long-lived pure β-particle-emitting radionuclide produced from 235 U fission and from neutron activation of the stable isotope 92 Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half-life, 93 Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Two different methodologies based on extractive resins and LSC and ICP-MS techniques that enables the 93 Zr determination in medium (ILW) and low level (LLW) radioactive wastes samples from Brazilian nuclear power plants has been developed in our laboratory. Analyzing real samples 65% and 75% chemical yields for 93 Zr recovery were achieved for ICP-MS and LSC techniques, respectively. The detection limits were 0.045 μg.L -1 for ICP-MS and 0.05 Bq.L -1 for LSC techniques. (author)

  6. Education based thinking and behaving? Towards an identity perspective for studying education differentials in public opinion and political participation

    Spruyt, Bram; Kuppens, Toon

    2015-01-01

    Education based thinking and behaving? Towards and identity perspective for studying education differentials in public opinion and political participation Abstract Ever since scholars started studying public opinion and political behaviour, they have reported substantial educational differences.

  7. The malate synthase of Paracoccidioides brasiliensis is a linked surface protein that behaves as an anchorless adhesin

    Pereira Maristela

    2009-12-01

    Full Text Available Abstract Background The pathogenic fungus Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis (PCM. This is a pulmonary mycosis acquired by inhalation of fungal airborne propagules that can disseminate to several organs and tissues leading to a severe form of the disease. Adhesion and invasion to host cells are essential steps involved in the internalization and dissemination of pathogens. Inside the host, P. brasiliensis may use the glyoxylate cycle for intracellular survival. Results Here, we provide evidence that the malate synthase of P. brasiliensis (PbMLS is located on the fungal cell surface, and is secreted. PbMLS was overexpressed in Escherichia coli, and polyclonal antibody was obtained against this protein. By using Confocal Laser Scanning Microscopy, PbMLS was detected in the cytoplasm and in the cell wall of the mother, but mainly of budding cells of the P. brasiliensis yeast phase. PbMLSr and its respective polyclonal antibody produced against this protein inhibited the interaction of P. brasiliensis with in vitro cultured epithelial cells A549. Conclusion These observations indicated that cell wall-associated PbMLS could be mediating the binding of fungal cells to the host, thus contributing to the adhesion of fungus to host tissues and to the dissemination of infection, behaving as an anchorless adhesin.

  8. Structural and morphological characterization of TiO2-ZrO2 powders obtained by the polymeric precursors method

    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S.; Bernardi, M.I.B.; Kiminami, R.H.G.A.

    2010-01-01

    This work aims to characterize the structure and morphology of TiO 2 -ZrO 2 powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO 2 in the anatase form and a tetragonal phase of ZrO 2 . The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO 2 nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  9. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs.

  10. A DFT study of thermodynamic properties of C36 and C14 Fe2Zr Laves phases

    Ali, Kawsar; Ghosh, P. S.; Arya, A. K.

    2018-04-01

    Fe-Zr alloys are promising materials for metallic waste immobilization in nuclear industry. C36 and C14 Fe2Zr Laves phases are frequently observed in Fe-Zr alloys that can host radionuclides. The phonon dispersions of C36 and C14 Fe2Zr Laves phases shows that both intermetallics are dynamically stable. The Helmholtz free energy, vibrational entropy, internal energy and specific heat at constant volume has been calculated. The zero point energies of C36 and C14 phases are 9.23 and 9.91 kJ/mole, respectively. The vibrational free energy becomes negative at 250 K and 270 K. The high temperature specific heat at constant volume of both intermetallics is 74 J/K/mole.

  11. NIR to visible frequency upconversion in Er3+ and Yb3+ codoped ZrO2 phosphor

    Singh, Vijay; Kim, Sang Hwan; Rai, Vineet Kumar; Al-Shamery, Katharina; Haase, Markus

    2013-01-01

    The ZrO 2 :Er 3+ codoped with Yb 3+ phosphor powders have been prepared by the urea combustion route. Formation of the compounds ZrO 2 :Er 3+ and ZrO 2 :Er 3+ , Yb 3+ was confirmed by XRD. The frequency upconversion emissions in the green and red regions upon excitation with a CW diode laser at ∝978 nm are reported. Codoping with Yb 3+ enhances the emission intensities of the triply ionized erbium in the green and red spectral regions by about ∝130 and ∝820 times respectively. The emission properties of the ZrO 2 :Er 3+ phosphor powders are discussed on the basis of excited state absorption, energy transfer, and cross-relaxation energy transfer mechanisms. (orig.)

  12. Research on aging precipitation in a Cu-Cr-Zr-Mg alloy

    Su Juanhua; Dong Qiming; Liu Ping; Li Hejun; Kang Buxi

    2005-01-01

    The effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy were investigated. Aging precipitation phase was dealt with by transmission electronic microscope (TEM). After solid solution was treated at 920 deg. C and aged at 470 deg. C for 4 h, the fine precipitation of an ordered compound CrCu 2 (Zr, Mg) is found in copper matrix as well as fine Cr and Cu 4 Zr. Along the grain boundary, there are larger chromium. The hardness and electrical conductivity can reach 109 HV and 80% IACS, respectively. Sixty percent cold-rolled deformation prior to aging at 470 deg. C enhances the hardness of the alloy. The coherent precipitates Cr in copper matrix and the dislocations pinned by the fine precipitates are responsible for maximum strengthening of the alloy. So the hardness 165 HV and electrical conductivity 79.2% IACS are available

  13. Mechanical Properties and Microstructure of TIG and FSW Joints of a New Al-Mg-Mn-Sc-Zr Alloy

    Xu, Guofu; Qian, Jian; Xiao, Dan; Deng, Ying; Lu, Liying; Yin, Zhimin

    2016-04-01

    A new Al-5.8%Mg-0.4%Mn-0.25%Sc-0.10%Zr (wt.%) alloy was successfully welded by tungsten inert gas (TIG) and friction stir welding (FSW) techniques, respectively. The mechanical properties and microstructure of the welded joints were investigated by microhardness measurements, tensile tests, and microscopy methods. The results show that the ultimate tensile strength, yield strength, and elongation to failure are 358, 234 MPa, and 27.6% for TIG welded joint, and 376, 245 MPa and 31.9% for FSW joint, respectively, showing high strength and superior ductility. The TIG welded joint fails in the heat-affected zone and the fracture of FSW joint is located in stirred zone. Al-Mg-Mn-Sc-Zr alloy is characterized by lots of dislocation tangles and secondary coherent Al3(Sc,Zr) particles. The superior mechanical properties of the TIG and FSW joints are mainly derived from the Orowan strengthening and grain boundary strengthening caused by secondary coherent Al3(Sc,Zr) nano-particles (20-40 nm). For new Al-Mg-Mn-Sc-Zr alloy, the positive effect from secondary Al3(Sc, Zr) particles in the base metal can be better preserved in FSW joint than in TIG welded joint.

  14. Enhancing MA transmutation by irradiation of (MA, Zr)Hx in FBR blanket region - 5383

    Konashi, K.; Ikeda, K.; Itoh, K.; Hirai, M.; Koyama, T.; Kurosaki, K.

    2015-01-01

    Minor actinide (MA) hydride is proposed as transmutation target in sodium-cooled mixed oxide fuelled fast reactor. Preliminarily calculations have been done to check the transmutation efficiency of MA hydride targets. Three different types of MA target, MA-Zr alloy, (MA, Zr)O 2 and (MA, Zr)H x , have been compared on MA transmutation rate. The targets are assumed to be loaded around an active core in a 280 MWe sodium-cooled reactor; 54 MA target assemblies are respectively arranged in a row in the radial blanket zone. They are supposed to be irradiated for one year and then be cooled for 60 days. The transmuted mass has been evaluated by three-dimensional diffusion calculation to be 25, 15, 61 kg/EFPY for the alloy, the oxide and the hydride respectively, where production of MA in the active core is taken into account. The transmutation mass by (MA, Zr)H x is much larger than those by the other types of targets, while the core characteristics remain sound by locating MA targets outside of the active core. On top of that, two kinds of (MA, Zr)O 2 targets which are combined with ZrH x (x=1.7) pins have been calculated. Major Research/Development items are selected to establish the MA hydride transmutation method by reviewing technologies applicable to the transmutation system. The practical use of the MA hydride transmutation method is not far ahead technically, since this method can be developed by the extension of existing technologies. (authors)

  15. Nanoindentation of ZrO{sub 2} and ZrO{sub 2}/Zr systems by molecular dynamics simulation

    Lu, Zizhe; Chernatynskiy, Aleksandr; Noordhoek, Mark J.; Sinnott, Susan B.; Phillpot, Simon R., E-mail: sphil@mse.ufl.edu

    2017-04-01

    The deformation behaviors of cubic zirconia and a cubic zirconia thin film on top of an hcp zirconium substrate are investigated using molecular dynamics nanoindentation simulation. Interatomic interactions are described by the previously developed Charge Optimized Many Body (COMB) potential for the Zr-ZrO{sub 2}-O{sub 2} system. The load-displacement curves, deformation processes and hardnesses of zirconia and the zirconia/zirconium systems are characterized. In addition, by comparing with a previous nanoindentation simulation on zirconium, the effects of the zirconia layer on top on the mechanical properties of the zirconium substrate are determined.

  16. Zr-ZrO sub 2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    Zhang Qi Chu; Lee, K D; Shen, Y G

    2003-01-01

    High solar performance Zr-ZrO sub 2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO sub 2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO sub 2 or Al sub 2 O sub 3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO sub 2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coating film w...

  17. Positron emission tomography imaging of CD105 expression with {sup 89}Zr-Df-TRC105

    Hong, Hao; Yang, Yunan [University of Wisconsin - Madison, Department of Radiology, Madison, WI (United States); Severin, Gregory W.; Engle, Jonathan W.; Zhang, Yin; Barnhart, Todd E.; Nickles, Robert J. [University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); Liu, Glenn [University of Wisconsin - Madison, Department of Medicine, Madison, WI (United States); University of Wisconsin Carbone Cancer Center, Madison, WI (United States); Leigh, Bryan R. [TRACON Pharmaceuticals, Inc, San Diego, CA (United States); Cai, Weibo [University of Wisconsin - Madison, Department of Radiology, Madison, WI (United States); University of Wisconsin - Madison, Department of Medical Physics, Madison, WI (United States); University of Wisconsin Carbone Cancer Center, Madison, WI (United States)

    2012-01-15

    High tumor microvessel density correlates with a poor prognosis in multiple solid tumor types. The clinical gold standard for assessing microvessel density is CD105 immunohistochemistry on paraffin-embedded tumor specimens. The goal of this study was to develop an {sup 89}Zr-based PET tracer for noninvasive imaging of CD105 expression. TRC105, a chimeric anti-CD105 monoclonal antibody, was conjugated to p-isothiocyanatobenzyl-desferrioxamine (Df-Bz-NCS) and labeled with {sup 89}Zr. FACS analysis and microscopy studies were performed to compare the CD105 binding affinity of TRC105 and Df-TRC105. PET imaging, biodistribution, blocking, and ex-vivo histology studies were performed on 4T1 murine breast tumor-bearing mice to evaluate the pharmacokinetics and tumor-targeting of {sup 89}Zr-Df-TRC105. Another chimeric antibody, cetuximab, was used as an isotype-matched control. FACS analysis of HUVECs revealed no difference in CD105 binding affinity between TRC105 and Df-TRC105, which was further validated by fluorescence microscopy. {sup 89}Zr labeling was achieved with high yield and specific activity. Serial PET imaging revealed that the 4T1 tumor uptake of {sup 89}Zr-Df-TRC105 was 6.1 {+-} 1.2, 14.3 {+-} 1.2, 12.4 {+-} 1.5, 7.1 {+-} 0.9, and 5.2 {+-} 0.3 %ID/g at 5, 24, 48, 72, and 96 h after injection, respectively (n = 4), higher than all organs starting from 24 h after injection, which provided excellent tumor contrast. Biodistribution data as measured by gamma counting were consistent with the PET findings. Blocking experiments, control studies with {sup 89}Zr-Df-cetuximab, and ex-vivo histology all confirmed the in vivo target specificity of {sup 89}Zr-Df-TRC105. We report here the first successful PET imaging of CD105 expression with {sup 89}Zr as the radiolabel. Rapid, persistent, CD105-specific uptake of {sup 89}Zr-Df-TRC105 in the 4T1 tumor was observed. (orig.)

  18. Evolution of Zr/Hf/Zr trilayers during annealing studied by RBS

    Kling, A.; Soares, J.C.

    2010-01-01

    The Zr/Hf system is highly interesting due its various applications, e.g. formation of amorphous ternary alloys, superconductive properties and production of gate oxide layers with high dielectric coefficients by oxidation of Zr/Hf multilayers. In this work Zr/Hf/Zr trilayers with an individual layer thickness of approximately 50 nm were deposited by electron gun evaporation on a substrate consisting of silicon covered by a micrometer thick thermal oxide layer. Samples were subjected to annealing procedures at 500 and 1200 o C in flowing air atmosphere to promote oxidation and Zr/Hf interdiffusion effects. RBS studies of the as-deposited and annealed samples were performed at the van-de-Graaff accelerator of ITN using He + and H + beams with energies between 2.0 and 2.525 MeV in order to study compositional changes induced by the heat treatment. In the case of low-temperature annealing the layer system appears, besides the oxidation process starting from the surface, to be stable. On the other hand, high-temperature annealing leads to an asymmetric Hf-diffusion into the surface and interior Zr-layer provoked by anomalous diffusion due to a phase transition in Zr accompanied by an almost complete oxidation of the layer structure Oxygen and metal depth distributions obtained by RBS in the as-deposited and treated samples are provided.

  19. Optical properties of Ar ions irradiated nanocrystalline ZrC and ZrN thin films

    Martin, C. [Ramapo College of New Jersey, Mahwah, NJ 07430 (United States); Miller, K.H. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Makino, H. [Research Institute, Kochi University of Technology, Kami, Kochi, 782-8502 (Japan); Craciun, D. [National Institute for Laser, Plasma, and Radiation Physics, Bucharest-Magurele (Romania); Simeone, D. [CEA/DEN/DANS/DM2S/SERMA/LEPP-LRC CARMEN CEN Saclay France & CNRS/ SPMS UMR8785 LRC CARMEN, Ecole Centrale de Paris, F92292, Chatenay Malabry (United States); Craciun, V., E-mail: valentin.craciun@inflpr.ro [National Institute for Laser, Plasma, and Radiation Physics, Bucharest-Magurele (Romania)

    2017-05-15

    Employing wide spectral range (0.06–6 eV) optical reflectance measurements and high energy X-ray photoemission spectroscopy (HE-XPS), we studied the effect of 800 keV Ar ion irradiation on optical and electronic properties of nanocrystalline ZrC and ZrN thin films, which were obtain by the pulsed laser deposition technique. Both in ZrC and ZrN, we observed that irradiation affects the optical properties of the films mostly at low frequencies, which is dominated by the free carriers response. In both materials, we found a significant reduction in the free carriers scattering rate and an increase of the zero frequency conductivity, i.e. possible increase in mobility, at higher irradiation fluence. This is consistent with our previous findings that irradiation affects the crystallite size and the micro-strain, but it does not induce major changes in the chemical bonding. HE-XPS investigations further confirms the stability of the Zr-C and Zr-N bonds, despite a small increase in the surface region of the Zr-O bonds fraction with increasing irradiation fluence.

  20. Optimasi Penempatan Menara BTS Menggunakan Quantum-Behaved Particle Swarm Optimization

    Mohamad Fatkhur Rohman

    2016-11-01

    Full Text Available Universal Mobile Telecomunication System (UMTS saat ini dipandang sebagai sebuah sistem impian yang menggantikan Global System for Mobile Communication (GSM dan merupakan salah satu evolusi generasi ketiga (3G dari jaringan mobile. Salah satu komponen pendukung jaringan UMTS adalah Node B, Node B dapat dianalogikan sebagai BTS. Seiring perkembangan kebutuhan pelanggan yang semakin meningkat, kebutuhan akan BTS(Node B semakin bertambah, hal ini menyebabkan banyaknya jumlah menara BTS da menyebabkan pemandangan yang kurang bagus bagi visualisasi kota.oleh karena itu perlu dilakukan optimisasi penempatan menara BTS. Salah satu metode untuk mengoptimasi adalah Quantum-behaved Particle Swarm Optimization. Maka dalam penelitian ini akan dirancang simulasi optimasi penempatan BTS menggunakan QPSO dengan parameter yang akan dioptimasi adalah Coverage Area dan Trafik. Dari hasil penelitian yang dilakukan, Algoritma QPSO mampu mengurangi jumlah BTS dari 55 BTS menjadi 43 BTS.

  1. Draft Tube Baffle (DTB) crystallizers: A study of stationary and dynamically behaving Crystal Size Distributions (CSD)

    Deleer, B. G. M.

    1981-11-01

    Based on population balance, CSD behavior as a function of geometrical and operating variables was studied, using a crystallizer. A potash alum-water system, involving a separation technique which uses surface active agents and an apolar, organic liquid to separate potash alum crystals from mother liquid under the influence of gravity was used to check experimental findings against literature data. Results show action of annular settling spaces is strongly influenced by fluid velocities perpendicular to those directed upwards. The well-mixed volume decreases with increasing crystallizer size until a minimum effective volume is reached. As supersaturation is constant throughout the crystallizer volume under stationary operating conditions, the annular settling space behaves like a growth chamber for crystals in its volume. Swirl in the lower part of the annular volume introduces significant back mixing. Crystals within this space either grow and return to the well-mixed part, or withdraw from the annular volume permanently.

  2. A Swarm Optimization Genetic Algorithm Based on Quantum-Behaved Particle Swarm Optimization.

    Sun, Tao; Xu, Ming-Hai

    2017-01-01

    Quantum-behaved particle swarm optimization (QPSO) algorithm is a variant of the traditional particle swarm optimization (PSO). The QPSO that was originally developed for continuous search spaces outperforms the traditional PSO in search ability. This paper analyzes the main factors that impact the search ability of QPSO and converts the particle movement formula to the mutation condition by introducing the rejection region, thus proposing a new binary algorithm, named swarm optimization genetic algorithm (SOGA), because it is more like genetic algorithm (GA) than PSO in form. SOGA has crossover and mutation operator as GA but does not need to set the crossover and mutation probability, so it has fewer parameters to control. The proposed algorithm was tested with several nonlinear high-dimension functions in the binary search space, and the results were compared with those from BPSO, BQPSO, and GA. The experimental results show that SOGA is distinctly superior to the other three algorithms in terms of solution accuracy and convergence.

  3. Parameters estimation online for Lorenz system by a novel quantum-behaved particle swarm optimization

    Gao Fei; Tong Hengqing; Li Zhuoqiu

    2008-01-01

    This paper proposes a novel quantum-behaved particle swarm optimization (NQPSO) for the estimation of chaos' unknown parameters by transforming them into nonlinear functions' optimization. By means of the techniques in the following three aspects: contracting the searching space self-adaptively; boundaries restriction strategy; substituting the particles' convex combination for their centre of mass, this paper achieves a quite effective search mechanism with fine equilibrium between exploitation and exploration. Details of applying the proposed method and other methods into Lorenz systems are given, and experiments done show that NQPSO has better adaptability, dependability and robustness. It is a successful approach in unknown parameter estimation online especially in the cases with white noises

  4. Rodent scope: a user-configurable digital wireless telemetry system for freely behaving animals.

    David Ball

    Full Text Available This paper describes the design and implementation of a wireless neural telemetry system that enables new experimental paradigms, such as neural recordings during rodent navigation in large outdoor environments. RoSco, short for Rodent Scope, is a small lightweight user-configurable module suitable for digital wireless recording from freely behaving small animals. Due to the digital transmission technology, RoSco has advantages over most other wireless modules of noise immunity and online user-configurable settings. RoSco digitally transmits entire neural waveforms for 14 of 16 channels at 20 kHz with 8-bit encoding which are streamed to the PC as standard USB audio packets. Up to 31 RoSco wireless modules can coexist in the same environment on non-overlapping independent channels. The design has spatial diversity reception via two antennas, which makes wireless communication resilient to fading and obstacles. In comparison with most existing wireless systems, this system has online user-selectable independent gain control of each channel in 8 factors from 500 to 32,000 times, two selectable ground references from a subset of channels, selectable channel grounding to disable noisy electrodes, and selectable bandwidth suitable for action potentials (300 Hz-3 kHz and low frequency field potentials (4 Hz-3 kHz. Indoor and outdoor recordings taken from freely behaving rodents are shown to be comparable to a commercial wired system in sorting for neural populations. The module has low input referred noise, battery life of 1.5 hours and transmission losses of 0.1% up to a range of 10 m.

  5. Al2TiO5-ZrTiO4-ZrO2 composites

    Parker, F.J.

    1990-01-01

    The characterization and properties of ceramic composites containing the phases Al 2 TiO 5 , ZrTiO 4 , and ZrO 2 are described. The low thermal expansions are apparently due to a combination of microcracking by the titanate phases and a contractive phase transformation by the ZrO 2 . The crystal chemistry and microstructure of the product are processing dependent. Although the composites represent a complex microcracking system, the low thermal expansions and high-temperature stability make them potential candidates for commercial application requiring thermal shock resistance

  6. Arc melting and homogenization of ZrC and ZrC + B alloys

    Darolia, R.; Archbold, T. F.

    1973-01-01

    A description is given of the methods used to arc-melt and to homogenize near-stoichiometric ZrC and ZrC-boron alloys, giving attention to the oxygen contamination problem. The starting material for the carbide preparation was ZrC powder with an average particle size of 4.6 micron. Pellets weighing approximately 3 g each were prepared at room temperature from the powder by the use of an isostatic press operated at 50,000 psi. These pellets were individually melted in an arc furnace containing a static atmosphere of purified argon. A graphite resistance furnace was used for the homogenization process.

  7. Time-temperature-transformation diagram of Zr-based Zr-Al-Cu-Ni metallic glasses

    Goh, T.T.; Li, Y.; Ng, S.C.

    1996-01-01

    The critical cooling rates R c for glass formation in four Zr-based Zr-Al-Cu-Ni alloys were determined using techniques developed by Uhlmann based on theories of homogeneous nucleation, crystal growth and transformation kinetics. It involves the construction of a time-temperature-transformation curve which requires the knowledge of the viscosity-temperature curve of the alloys. Two types of viscosity-temperature expressions, namely Andrade expression and Doolittle expression, were used to model the viscosity of the Zr-based alloys and the choice of the viscosity-temperature expression which gives the best estimate of the calculated time-temperature-transformation curve is discussed. (author)

  8. Microstructural evolution and structure property correlation in Zr-1Nb and Zr-1Nb-1Sn-0.1Fe alloys

    Neogy, S.; Srivastava, D.; Chakravartty, J.K.; Dey, G.K.

    2005-01-01

    This study summarizes the evolution of microstructure and precipitation behavior in binary Zr-1Nb and quaternary Zr-1Nb-1Sn-0.1Fe alloys after different thermo mechanical processing. The processed microstructure and morphology of constituent phases and precipitates have been studied in detail using transmission electron microscopy (TEM). Microstructural studies have revealed the shape, size, size distribution and the nature of precipitate phases. Martensite formation and its tempering behavior have been studied in detail in both the alloys. Recrystallization studies on these alloys have been carried out with a view to understand the recrystallization mechanism. In case of the binary alloy the second phase recipitates were of the β type having composition varying from β I (20 wt% Nb) to β II (85 wt% Nb) depending on the heat treatment temperature and time. The second phase precipitates in the quaternary alloy were intermetallic Zr-Nb-Fe type and also β type rich in Zr. The orientation relationship existing between the precipitating phases and the a matrix were established in case of both the alloys. High resolution electron microscopy (HREM) of the martensitic microstructure and the recrystallized microstructure has revealed the internal structure and the interface structure of the martensite and the precipitating phases respectively. Structure-property correlation studies have been carried out on the heat-treated samples to evaluate the effect of the thermo mechanical processing on the microstructures and hence mechanical properties. (author)

  9. Local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys investigated by EXAFS method

    Antonowicz, J.; Pietnoczka, A.; Zalewski, W.; Bacewicz, R.; Stoica, M.; Georgarakis, K.; Yavari, A.R.

    2011-01-01

    Research highlights: → Coordination number, interatomic distances and mean square atomic displacement in Zr-Cu and Zr-Cu-Al glasses. → Icosahedral symmetry in local atomic structure. → Deviation from random mixing behavior resulting from Al addition. - Abstract: We report on extended X-ray absorption fine structure (EXAFS) study of rapidly quenched Zr-Cu and Zr-Cu-Al glassy alloys. The local atomic order around Zr and Cu atoms was investigated. From the EXAFS data fitting the values of coordination number, interatomic distances and mean square atomic displacement were obtained for wide range of compositions. It was found that icosahedral symmetry rather than that of corresponding crystalline analogs dominates in the local atomic structure of Zr-Cu and Zr-Cu-Al amorphous alloys. Judging from bonding preferences we conclude that addition of Al as an alloying element results in considerable deviation from random mixing behavior observed in binary Zr-Cu alloys.

  10. Effect of pH on corrosion behavior of CuCrZr in solution without and with NaCl

    Kwok, C.T.; Wong, P.K. [Department of Electromechanical Engineering, University of Macau (China); Man, H.C. [Department of Industrial and Systems Engineering, Hong Kong Polytechnic University (Hong Kong); Cheng, F.T., E-mail: apaftche@polyu.edu.h [Department of Applied Physics, Hong Kong Polytechnic University (Hong Kong)

    2009-10-01

    CuCrZr is a high copper alloy widely used as electrical and thermal conducting material, especially in heat exchangers in nuclear reactors. In this respect, the physical and fatigue properties of CuCrZr have been extensively studied. The electrochemical behavior of CuCrZr, on the other hand, has not been adequately investigated. In the present study, the effect of pH on the corrosion behavior of CuCrZr in aqueous solutions without and with chloride (0.6 M NaCl) was studied. The pH of the solutions is found to exert significant influence on the corrosion behavior of CuCrZr. In acidic solutions without chloride, the corrosion of CuCrZr is ascribed to active dissolution with soluble products. In neutral and alkaline solutions without NaCl, the presence of oxides on the surface of CuCrZr leads to a noble shift in corrosion potential and passivation results in increased corrosion resistance. In chloride solutions at various pH values, the chloride ions influence the formation of the surface layers and the anodic dissolution process during polarization. At high pH, CuCrZr shows significant passivity and high corrosion resistance due to the growth of Cu{sub 2}O/Cu(OH) film which hinders further dissolution whereas at low pH the corrosion resistance is lowered due to active dissolution of Cu.

  11. Silica-gel Particles Loaded with an Ionic Liquid for Separation of Zr(IV Prior to Its Determination by ICP-OES

    Hadi M. Marwani

    2016-06-01

    Full Text Available A new ionic liquid loaded silica gel amine (SG-APTMS-N,N-EPANTf2 was developed, as an adsorptive material, for selective adsorption and determination of zirconium, Zr(IV, without the need for a chelating intermediate. Based on a selectivity study, the SG-APTMS-N,N-EPANTf2 phase showed a perfect selectivity towards Zr(IV at pH 4 as compared to other metallic ions, including gold [Au(III], copper [Cu(II], cobalt [Co(II], chromium [Cr(III], lead [Pb(II], selenium [Se(IV] and mercury [Hg(II] ions. The influence of pH, Zr(IV concentration, contact time and interfering ions on SG-APTMS-N,N-EPANTf2 uptake for Zr(IV was evaluated. The presence of incorporated donor atoms in newly synthesized SG-APTMS-N,N-EPANTf2 phase played a significant role in enhancing its uptake capacity of Zr(IV by 78.64% in contrast to silica gel (activated. The equilibrium and kinetic information of Zr(IV adsorption onto SG-APTMS-N,N-EPANTf2 were best expressed by Langmuir and pseudo second-order kinetic models, respectively. General co-existing cations did not interfere with the extraction and detection of Zr(IV. Finally, the analytical efficiency of the newly developed method was also confirmed by implementing it for the determination of Zr(IV in several water samples.

  12. Effect of pH on corrosion behavior of CuCrZr in solution without and with NaCl

    Kwok, C.T.; Wong, P.K.; Man, H.C.; Cheng, F.T.

    2009-01-01

    CuCrZr is a high copper alloy widely used as electrical and thermal conducting material, especially in heat exchangers in nuclear reactors. In this respect, the physical and fatigue properties of CuCrZr have been extensively studied. The electrochemical behavior of CuCrZr, on the other hand, has not been adequately investigated. In the present study, the effect of pH on the corrosion behavior of CuCrZr in aqueous solutions without and with chloride (0.6 M NaCl) was studied. The pH of the solutions is found to exert significant influence on the corrosion behavior of CuCrZr. In acidic solutions without chloride, the corrosion of CuCrZr is ascribed to active dissolution with soluble products. In neutral and alkaline solutions without NaCl, the presence of oxides on the surface of CuCrZr leads to a noble shift in corrosion potential and passivation results in increased corrosion resistance. In chloride solutions at various pH values, the chloride ions influence the formation of the surface layers and the anodic dissolution process during polarization. At high pH, CuCrZr shows significant passivity and high corrosion resistance due to the growth of Cu 2 O/Cu(OH) film which hinders further dissolution whereas at low pH the corrosion resistance is lowered due to active dissolution of Cu.

  13. Fabrication and Thermophysical Properties of La(2-x)Zr(2-y)O7 Nanocrystal by a Sol-Gel Method.

    Li, Hui; Che, Ping; Zhao, Ziqiang; Liu, Shixiang; Li, Wenjun

    2016-03-01

    Non-Stoichiometric La2Zr2O7 (La(2-x)Zr(2-y)O7) Nanocrystal was synthesized by a simple sol-gel method. The crystalline structure, oxygen vacancy concentration, thermal expansion coefficient, as well as the fracture toughness of as-prepared materials were charactered by XRD, TG-DSC, PL spectra, dilatometer, and electronic universal testing machine respectively. The crystal structure of La2Zr2O7 is of the cubic type while lattice parameter increases with the deviatation of Zr4+ and La3+ from Stoichiometric La2Zr2O7 increasing. The average linear thermal expansion coefficient of non-stoichiometric La2Zr2O7 is obviously bigger than that of La2Zr2O7 in the temperature range between 150 degrees C and 950 degrees C. The fracture toughness of La(2-x)Zr(2-y)O7 increases with x and y increasing up to x = 0.3 and y = 0.25.

  14. A peristaltic pump driven 89Zr separation module

    Siikanen, J.; Peterson, M.; Tran, T.

    2012-01-01

    To facilitate the separation of 89Zr produced in yttrium foils, an automated separation module was designed and assembled. The module separates more than 85% of produced 89Zr - activity in 3 g foils in less than 90 min. About 10 % remains in the dissolving vial. The quality of the separated 89Zr...

  15. Magnetic properties of Dy/Zr multilayers

    Luche, M.C.; Boyer, P.

    1992-01-01

    [Dy(xA)/Zr(30A)] n superlattices (x ≤ 30), were evaporated under ultra-high vacuum on Si(100) substrates. Magnetization measurements indicate that the antiferromagnetic transition occurring at 178K in bulk Dy is suppressed in the multilayers. This phenomenon is attributed to magnetoelastic effects induced by strains at Zr/Dy interfaces. A perpendicular magnetic anisotropy takes place for x ≤ 15. However, the magnetic anisotropy is found to depend markedly on the technique used for Dy deposition. (author). 11 refs., 4 figs

  16. Preparation and determination of the luminescent characteristics of ZrO{sub 2} in powder; Preparacion y determinacion de las caracteristicas luminiscentes del ZrO{sub 2} en polvo

    Rivera M, T. [ESIME-IPN Unidad Culhuacan Mexico D.F. (Mexico); Olvera T, L.; Azorin N, J.; Soto E, A.M.; Velazquez O, C.; Campero C, A. [UAM-I, 09340 Mexico D.F. (Mexico)

    2004-07-01

    In this work the luminescent characteristics of the ZrO{sub 2} are presented using the method of Thermally Stimulated Luminescence (TSL), also called thermoluminescence (Tl). The powders of ZrO{sub 2} were obtained by two preparation methods: for precipitation and for evaporation of Sol-gel. The luminescent characteristics of the ZrO{sub 2} are determined using a lamp of radiation of UV light and a radiation source of beta particles of {sup 90}Sr/{sup 90}Y. Using the method of thermal stimulation the curve representative thermoluminescent of the previously irradiated material was obtained. The curve Tl of the ZrO{sub 2} irradiated with UV light presents a maximum in 180 C. Likewise, the spectrum of the curve Tl of the ZrO{sub 2} irradiated with particles beta presents a maximum centered in 181 C. While using gamma radiation like excitement source one has a spectrum with a peak centered in 184 C. When subjecting the materials obtained by sol-gel to a process of calcination at 1000 C for 24 hours a curved Tl it presents with two maxim in 185 and in 290 C respectively. The intensity of the response induced in the material it is a decisive factor to continue studying the dosimetric characteristics of the ZrO{sub 2} what allows to consider it as a potential material to use it in the beta particle dosimetry and of the UV light using the thermoluminescence method (Tl). (Author)

  17. Site preference of Zr in Ti 3 Al and phase stability of Ti 2 ZrAl

    Calculated values of equilibrium lattice parameters, heat of formation and bulk modulus of Ti2ZrAl are presented. The basis for the structural stability and bonding are analysed in terms of the density of states. Between the two possible 2-like structures, Ti2ZrAl shows enhanced stability for the one where Zr is substituted in ...

  18. Effects of Zr4+ codoping on the Lu0.8Sc0.2BO3:Ce scintillation materials

    Wu, Yuntao; Ren, Guohao; Ding, Dongzhou; Shang, Shanshan; Sun, Dandan; Zhang, Guoqing; Wang, Jiayu; Pan, Shangke; Yang, Fan

    2013-01-01

    Both Zr-codoped Lu 0.8 Sc 0.2 BO 3 :Ce polycrystalline powders and single crystals were obtained by solid-state reaction and Czochralski method, respectively. The effects of Zr codoping on the optical absorption, Ce 3+ /Ce 4+ ratio, scintillation efficiency, decay time and point defect in Lu 0.8 Sc 0.2 BO 3 :Ce materials were examined systematically. Our results show that there is no positive contribution of Zr 4+ ion codoping to the scintillation efficiency. And the reasons for the deterioration of scintillation efficiency by codoping Zr 4+ were revealed. - Highlights: ► No positive contribution of the Zr 4+ ions on the scintillation efficiency was found. ► New optical absorption band was in the region from 200 to 225 nm. ► Continuously accelerated decay time indicated that Zr 4+ codoping induced new point defects. ► The induced hole trap located at 1.91 eV below the conduction band.

  19. Structural, vibrational and morphological properties of layered double hydroxides containing Ni2+, Zn2+, Al3+ and Zr4+ cations

    Bezerra, Débora M.; Rodrigues, João E.F.S.; Assaf, Elisabete M.

    2017-01-01

    Layered double hydroxides are anionic clays with formula [M II 1−x M III x (OH) 2 ] q+ [A n− ] q/n ·mH 2 O, finding possible uses as catalyst support, adsorbents and so on. In this paper, we address the phase formation of layered double hydroxides containing Ni 2+ , Zn 2+ , Al 3+ and Zr 4+ cations, namely, NiZn-Al, NiZn-AlZr and NiZn-Zr compositions obtained by the coprecipitation method. Such systems were characterized by X-ray diffraction, confirming the phase formation for NiZn-Al and NiZn-AlZr samples. Infrared and Raman spectroscopies elucidated the anion and water molecules occurrence in the interlayer. Nitrogen physisorption (BET method) determined the presence of pores and specific surface area. The isotherm shapes were Type IV, according to the IUPAC, and represent a mesoporous structure. A morphological study was performed by means of scanning and transmission electron microscopies, and particle size values of 120, 131 and 235 nm for NiZn-Al, NiZn-AlZr and NiZn-Zr, respectively, were determined. Thermogravimetric analysis of the decomposition of the systems revealed that their complete disintegration occurred at ~ 450 °C and resulted in mixed oxides.

  20. Energetics of gaseous and volatile fission products in molten U–10Zr alloy: A density functional theory study

    Wang, Ning; Tian, Jie; Jiang, Tao; Yang, Yanqiu; Hu, Sheng [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Peng, Shuming, E-mail: pengshuming@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999 (China); Yan, Liuming [Department of Chemistry, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

    2015-11-15

    Gaseous and volatile fission products have a number of adverse effects on the safety and efficiency of the U–10Zr alloy fuel. The theoretical calculations were applied to investigate the energetics related to the formation, nucleation, and degassing of gaseous and volatile fission products (Kr, Xe and I) in molten U–10Zr alloy. The molecular dynamics (MD) simulations were applied to generate equilibrium configurations. The density functional theory (DFT) calculations were used to build atomistic models including molten U–10Zr alloy as well as its fission products substituted systems. The vacancy formation in liquid U–10Zr alloy were studied using DFT calculations, with average Gibbs free formation energies at 8.266 and 6.333 eV for U- and Zr-vacancies, respectively. And the interaction energies were −1.911 eV, −2.390 eV, and −1.826 eV for the I–I, Xe–Xe, and Kr–Kr interaction in lattice when two of the adjacent uranium atoms were substituted by gaseous atoms. So it could be concluded that the interaction between I, Kr, and Xe in lattice is powerful than the interaction between these two atoms and the other lattice atoms in U–10Zr.

  1. Characteristics of slowly cooled Zr-Al-Cu-Ni bulk samples with different oxygen content

    Gebert, A.; Eckert, J.; Bauer, H.-D.; Schultz, L.

    1998-01-01

    Bulk samples of the glass-forming Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 alloys with 3 mm diameter were prepared by die casting into a copper mould. The oxygen content of the samples was varied between 0.26 at.% and 0.73 at.% by adjusting the oxygen partial pressure in the argon atmosphere upon casting. Characterization of the microstructure of as-cast samples and of specimens continuously heated to 873 K was carried out by X-ray diffraction (XRD), optical microscopy (OM) and transmission electron microscopy (TEM). Thermal stability was investigated by constant-rate differential scanning calorimetry (DSC). The phase formation and the thermal stability of the slowly cooled zirconium-based bulk samples are essentially influenced by the oxygen content of the material. Furthermore, the sensitivity to oxygen depends on the composition of the alloy. In bulk Zr 65 Al 7.5 Cu 17.5 Ni 10 samples only small oxygen traces induce nucleation and crystal growth during slow cooling whereas Zr 55 Al 10 Cu 30 Ni 5 samples are completely amorphous for all oxygen contents investigated. The processes of the oxygen-induced phase formation are discussed in detail also with respect to the results obtained for the heat treated samples. With increasing oxygen content the thermal stability deteriorates, as it is obvious from a diminution of the supercooled liquid region (ΔT x = T x - T g ) which is mainly due to a reduction of the crystallization temperature T x . Furthermore, the thermal behaviour of Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 reveals significant differences. (orig.)

  2. Interphase Constituent of Laminated Composites Ti46Zr26Cu17Ni11

    XU Bingtong

    2017-10-01

    Full Text Available Thermal analysis of the Ti46Zr26Cu17Ni11 amorphous ribbon prepared by melt spinning was conducted by using DSC. Accordingly the amorphous alloy was treated by vacuum heat treatment at 693 K (Tg, 753 K (Tg-Tx1 and 813 K (> Tx1 for different time to analyze the crystallization behavior. Taking Ti46Zr26Cu17Ni11 amorphous alloy, TA2 and pure Al as raw materials, laminated composites were fabricated by Gleeble-3500 thermal simulator at 873 K, 10 MPa and 8 h. The phase composition, precipitation order and properties of interface layers were investigated by SEM, TEM, micro hardness tester, combined thermodynamics and element diffusion theory. The results indicate that the glass transition temperature Tg of Ti46Zr26Cu17Ni11 amorphous is 720 K and the initial crystallization temperature Tx1 is 788 K. The I phase is crystallized from the amorphous at first, followed by a ternary or quaternary Laves phase and a TiNi phase precipited. After hot pressing, the interface between pure Al and crystallization layer is divided into two parts, which are Al3Ni with small thickness and Al3(Ti0.6Zr0.4 with fine grain and uniform microstructure. The interfaces are straight and there are no defects, with a thickness ratio of about 6.5:1 compared with interface layer between pure Ti with Al. The hardness of Al3(Ti0.6Zr0.4 and Al3Ti are 564.2HV and 579.8HV respectively. The plasticity of Al3(Ti0.6Zr0.4 layer is better.

  3. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-01-01

    Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO 2 , ZrO 2 , V 2 O 5 , Al 2 O 3 , etc.), metal fluoride (ZrF 4 , AlF 3 , etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  4. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Zhu, Wen; Li, Wenfang, E-mail: mewfli@scut.edu.cn; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-30

    Highlights: • A non-chrome titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating is prepared on AA6063 at room temperature. • The Ti/Zr/V conversion coating is produced on AA6063 within 50 s. • The adhesion strength between epoxy coating and AA6063 is improved significantly after the Ti/Zr/V conversion treatment. - Abstract: An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5}, Al{sub 2}O{sub 3}, etc.), metal fluoride (ZrF{sub 4}, AlF{sub 3}, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  5. The ambient and high temperature deformation behavior of Al–Si–Cu–Mg alloy with minor Ti, Zr, Ni additions

    Hernandez-Sandoval, J.; Garza-Elizondo, G.H.; Samuel, A.M.; Valtiierra, S.; Samuel, F.H.

    2014-01-01

    Highlights: • Characterization on the precipitation of Ni- and Zr-based intermetallics. • High temperature tensile properties of 354 alloy containing Zr and Ni below 0.5%. • Quality index charts as a function of heat treatment. • Yield strength and ductility color contours as a function of aging temperature and aging time. - Abstract: The principal aim of the present work was to investigate the effects of minor additions of nickel and zirconium on the strength of cast aluminum alloy 354 at ambient and high temperatures. Tensile properties of the as-cast and heat-treated alloys were determined at room temperature and at high temperatures (190 °C, 250 °C, 350 °C). The results show that Zr reacts only with Ti, Si and Al. From the quality index charts constructed for these alloys, the quality index attains minimum and maximum values of 259 MPa and 459 MPa, in the as-cast and solution-treated conditions; also, maximum and minimum values of yield strength are observed at 345 MPa and 80 MPa, respectively, within the series of aging treatments applied. A decrease in tensile properties of ∼10% with the addition of 0.4 wt.% nickel is attributed to a nickel–copper reaction. The reduction in mechanical properties due to addition of different elements is attributed principally to the increase in the percentage of intermetallic phase particles formed during solidification; such particles act as stress concentrators, decreasing the alloy ductility. Tensile test results at ambient temperatures show a slight increase (∼10%) in alloys with Zr and Zr/Ni additions, particularly at aging temperatures above 240 °C. Additions of Zr and Zr + Ni increase the high temperature tensile properties, in particular for the alloy containing 0.2 wt.% Zr + 0.2 wt.% Ni, which exhibits an increase of more than 30% in the tensile properties at 300 °C compared with the base 354 alloy

  6. Phase diagram of the ternary Zr-Ti-Sn system

    Arias, D.; Gonzalez Camus, M.

    1987-01-01

    It is well known that Ti stabilizes the high temperature cubic phase of Zr and that Sn stabilizes the low temperature hexagonal phase of Zr. The effect of Sn on the Zr-Ti diagram has been studied in the present paper. Using high purity metals, nine different alloys have been prepared, with 4-32 at % Ti, 0.7-2.2 at % Sn and Zr till 100%. Resistivity and optical and SEM metallography techniques have been employed. Effect of some impurities have been analyzed. The results are discussed and different isothermic sections of the ternary Zr-Ti-Sn diagram are presented. (Author) [es

  7. Mechanical testings on hydrurated Zr, Zry-4 and Zr-2.5 Nb under neutronic irradiation

    Vazquez, Carolina A.; Fortis, Ana M.

    2007-01-01

    In this work the measurements of irradiation hardening made on hydrurated and irradiated Zr and Zr alloys are presented. The irradiations were carried out in the RA-1 reactor at neutron fluences below those were the inhomogeneities of the deformation occur. It is observed an important difference in the mechanical behavior between the alloys according to the thermal treatments and the hydrogen contents. (author) [es

  8. Development of Zr alloys - Fabrication of Zr-Nb alloy used in PHWRs

    Lee, Kang In; Kim, Won Baek; Choi, Guk Sun; Lee, Chul Kyung; Jang, Dae Kyu; Seo, Chang Yeol; Sim, Kun Joo; Lee, Jae Cheon [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-07-01

    The manufacture of Zr-Nb alloy ingot by EB melting process is carried out to meet the chemical composition and mechanical and property specifications and to ensure that the ingots are free of unacceptable defects through this study. It was established that Zr-Nb alloy was made by EB melting technique including the control of adding elements, melting power and melting and cast device. 28 refs., 13 tabs., 26 figs., 23 ills. (author)

  9. Double γ decay in 90Zr

    Mucciolo, E.R.

    1988-01-01

    The double γ decay between θ + n - θ + i of 90 Zr was observed. The θ + n level was fed through the decay of 90 Sr. The experimental arrangement consisted of a double coincidence system between the two semiconductor detectors. (A.C.A.S.) [pt

  10. Phase transformations on Zr-Nb alloys

    Doi, Sergio Norifumi

    1980-01-01

    This research intended the laboratory scale experimental development of Zr-Nb alloys with adequate characteristics for use as fuel element cladding or for the making of irradiation capsules. Zr-Nb alloys with different Nb contents were melted and the resulting material was characterised. The following metallurgical aspects were considered: preparation of Zr-Nb alloys with various Nb contents; heat and thermomechanical treatments; microstructural characterization; mechanical properties; oxidation properties. The influence of the heat treatment and thermomechanical treatment, on the out-of-pile mechanical and oxidation properties of the Zr-Nb alloys were studied. It was found that the alloy microhardness increases with the Nb content and/or with the thermomechanical treatment. Mechanical properties such as yield and ultimate tensile strength as well as elongation were determined by means of compression tests. The results showed that the alloy yield stress increases with the Nb content and with the thermomechanical treatment, while its elongation decreases. Thermogravimetric analysis determined the alloy oxidation kinetics, in the 400 - 800 deg C interval, at 1 atm. oxygen pressure. The results showed that the alloy oxidation rate increases with the temperature and Nb content. It was also observed that the oxidation rate increases considerably for temperatures higher than 600 deg C.(author)

  11. Grain boundary sinks in neutron-irradiated Zr and Zr-alloys

    Griffiths, M.; Gilbert, R.W.; Coleman, C.E.

    1988-01-01

    Samples of annealed sponge and crystal-bar Zr and Zircaloy-2 have been examined following irradiation in EBR-II at temperatures ≅ 700 K. Loop analysis shows that there is selective denuding of interstitial loops near to some grain boundaries indicating that such boundaries are net sinks for interstitial point defects. Furthermore, in sponge Zr and Zircaloy-2, vacancy c-component loops are observed running into the grain boundaries showing that the grain boundaries are not preferred sinks for vacancies. Cavities are observed in all samples. In crystal-bar Zr and sponge Zr they are mostly observed adjacent to grain boundaries. They are also sometimes found within grains associated with precipitates. The cavities are more common in the crystal-bar Zr and this is probably because both the sponge Zr and Zircaloy-2 contain vacancy c-component loops which compete for vacancies (assuming that the cavities are vacancy sinks). Only some of the grain boundaries have cavities adjacent to them and this may be related to the orientation of the boundary. (orig.)

  12. The preparation of Zr-deuteride and phase stability studies of the Zr-D system

    Maimaitiyili, T.; Steuwer, A.; Bjerkén, C.; Blomqvist, J.; Hoelzel, M.; Ion, J. C.; Zanellato, O.

    2017-03-01

    Deuteride phases in the zirconium-deuterium system in the temperature range 25-286 °C have been studied in-situ by high resolution neutron diffraction. The study primarily focused on observations of δ→γ transformation at 180 °C, and the peritectoid reaction α + δ ↔ γ at 255 °C in commercial grade Zr powder that was deuterated to a deuterium/Zr ratio of one to one. A detailed description of the zirconium deuteride preparation route by high temperature gas loading is also described. The lattice parameters of α-Zr, δ-ZrDx and ε-ZrDx were determined by whole pattern crystal structure analysis, using Rietveld and Pawley refinements, and are in good agreement with values reported in the literature. The controversial γ-hydride phase was observed both in-situ and ex-situ in deuterated Zr powder after a heat treatment at 286 °C and slow cooling.

  13. Zr-rich corner of the Zr-Sn-O diagram

    Roberti, L.A.; Arias, D.E.

    1993-01-01

    The understanding of the effect of light elements (in particular oxygen, nitrogen and hydrogen) on the behaviour of alloys for nuclear use is necessary because of its technological importance. The Zr-Sn-O system is perhaps the most representative of all possible ternary systems which can be used to simulate a simplified Zircaloy-type alloy in which the effect of O can be studied. However, in the specialized literature experimental data on phase equilibria and thermophysical properties of this system are not easily found. In the present work, the equilibrium compositions of the α and β phases of the Zr-Sn-O system at temperatures between 1150 and 1323 K are calculated, using the scarce available information. First results of the calculations show satisfactory coincidences with experimental data. Future work will be oriented towards the proposal of isothermal cross-sections calculated by a modelling of phases with wider Sn and O composition ranges, and involving equilibria with the phases Zr 4 Sn, Zr 5 Sn 3 , ZrO 2 , ZrSnO 4 . (Author)

  14. Influence of Temperature to Thermal Properties of U-Zr Alloy With The Zr Content Variation

    Aslina-Br-Ginting; Masrukan; M-Husna-Al-Hasa

    2007-01-01

    Have been done thermal of characteristic covering heat stability, heat capacities, enthalpy and also phase changes from uranium, zirkonium and U-Zr alloy with the Zr content variation of Zr 2 %, 6 %, 10% and 14% weight. Change of the temperature and composition anticipated will cause the characteristic of thermal to uranium metal, zirkonium and also U-Zr alloy. Therefore at this research was conducted using analysis influence of temperature to thermal of characteristic of uranium, zirkonium and U-Zr alloy with the Zr content variation by using DTA and DSC. Result of analysis indicate that the uranium metal at temperature 662 o C stable in phase α. Above at temperature, uranium metal experience of the phase change indicated by formed the thermochemical reaction as much 3 endothermic peak. At temperature 667.16 o C, happened by the phase change of α become the phase β with the enthalpy 2,3034 cal/g, at temperature 773.05 o C happened by the phase change β becoming phase γ 2,8725 cal/g and also at temperature 1125.26 the o C uranium metal experience the phenomenon become to melt with the enthalpy 2,1316 cal/g. (author)

  15. Evidence for Long-Timescale Patterns of Synaptic Inputs in CA1 of Awake Behaving Mice.

    Kolb, Ilya; Talei Franzesi, Giovanni; Wang, Michael; Kodandaramaiah, Suhasa B; Forest, Craig R; Boyden, Edward S; Singer, Annabelle C

    2018-02-14

    Repeated sequences of neural activity are a pervasive feature of neural networks in vivo and in vitro In the hippocampus, sequential firing of many neurons over periods of 100-300 ms reoccurs during behavior and during periods of quiescence. However, it is not known whether the hippocampus produces longer sequences of activity or whether such sequences are restricted to specific network states. Furthermore, whether long repeated patterns of activity are transmitted to single cells downstream is unclear. To answer these questions, we recorded intracellularly from hippocampal CA1 of awake, behaving male mice to examine both subthreshold activity and spiking output in single neurons. In eight of nine recordings, we discovered long (900 ms) reoccurring subthreshold fluctuations or "repeats." Repeats generally were high-amplitude, nonoscillatory events reoccurring with 10 ms precision. Using statistical controls, we determined that repeats occurred more often than would be expected from unstructured network activity (e.g., by chance). Most spikes occurred during a repeat, and when a repeat contained a spike, the spike reoccurred with precision on the order of ≤20 ms, showing that long repeated patterns of subthreshold activity are strongly connected to spike output. Unexpectedly, we found that repeats occurred independently of classic hippocampal network states like theta oscillations or sharp-wave ripples. Together, these results reveal surprisingly long patterns of repeated activity in the hippocampal network that occur nonstochastically, are transmitted to single downstream neurons, and strongly shape their output. This suggests that the timescale of information transmission in the hippocampal network is much longer than previously thought. SIGNIFICANCE STATEMENT We found long (≥900 ms), repeated, subthreshold patterns of activity in CA1 of awake, behaving mice. These repeated patterns ("repeats") occurred more often than expected by chance and with 10 ms

  16. A study on the delayed hydride cracking mechanism in cold worked Zr-2.5Nb, heat treated Zr-2.5Nb and zircaloy-2 pressure tubes

    Choi, Kwang Sik

    1992-02-15

    Cold worked Zr-2.5Nb, heat treated Zr-2.5Nb and Zircaloy-2 pressure tubes were hydrided to the hydrogen concentration of 68 ppm, 49 ppm and 242-411 ppm, respectively, and compact tension specimens were machined from the hydrided materials. The crack growth rate by delayed hydride cracking was measured by potential drop method at various temperatures on the above mentioned three types of specimens. The activation energy obtained were 43 KJ/mol for cold worked Zr-2.5Nb and 37 KJ/mol for heat treated Zr-2.5Nb, which were in good agreements with that of Coleman (1977), while they were lower than the activation energy of 65.5 KJ/mol obtained by Simpson-puls (1979) and 71.5 KJ/mol by Ambler (1984). The DHC growth rate in Zircaloy-2 were about one fifth of that of Zr-2.5Nb, which is due to the texture and material strength effects. Striations which indicate stepwise DHC growth were observed at fracture surface by scanning electron microscope and unsymmetric crack tunnellings were also observed, which seems to be due to the difference in hydrogen diffusion rate caused by the difference in stress fields between inner and outer surface. The comparison of test results with the DHC growth rate calculated by Simpson-puls model showed good agreement at high temperatures, whereas at the lower temperatures the crack growth rates were 2.5 times higher than the calculated values.

  17. A study on the delayed hydride cracking mechanism in cold worked Zr-2.5Nb, heat treated Zr-2.5Nb and zircaloy-2 pressure tubes

    Choi, Kwang Sik

    1992-02-01

    Cold worked Zr-2.5Nb, heat treated Zr-2.5Nb and Zircaloy-2 pressure tubes were hydrided to the hydrogen concentration of 68 ppm, 49 ppm and 242-411 ppm, respectively, and compact tension specimens were machined from the hydrided materials. The crack growth rate by delayed hydride cracking was measured by potential drop method at various temperatures on the above mentioned three types of specimens. The activation energy obtained were 43 KJ/mol for cold worked Zr-2.5Nb and 37 KJ/mol for heat treated Zr-2.5Nb, which were in good agreements with that of Coleman (1977), while they were lower than the activation energy of 65.5 KJ/mol obtained by Simpson-puls (1979) and 71.5 KJ/mol by Ambler (1984). The DHC growth rate in Zircaloy-2 were about one fifth of that of Zr-2.5Nb, which is due to the texture and material strength effects. Striations which indicate stepwise DHC growth were observed at fracture surface by scanning electron microscope and unsymmetric crack tunnellings were also observed, which seems to be due to the difference in hydrogen diffusion rate caused by the difference in stress fields between inner and outer surface. The comparison of test results with the DHC growth rate calculated by Simpson-puls model showed good agreement at high temperatures, whereas at the lower temperatures the crack growth rates were 2.5 times higher than the calculated values

  18. Anodic Fabrication of Ti-Nb-Zr-O Nanotube Arrays

    Qiang Liu

    2014-01-01

    Full Text Available Highly ordered Ti-Nb-Zr-O nanotube arrays were fabricated through pulse anodic oxidation of Ti-Nb-Zr alloy in 1 M NaH2PO4 containing 0.5 wt% HF electrolytes. The effect of anodization parameters and Zr content on the microstructure and composition of Ti-Nb-Zr-O nanotubes was investigated using a scanning electron microscope equipped with energy dispersive X-ray analysis. It was found that length of the Ti-Nb-Zr-O nanotubes increased with increase of Zr contents. The diameter and the length of Ti-Nb-Zr-O nanotubes could be controlled by pulse voltage. XRD analysis of Ti-Nb-Zr-O samples annealed at 500°C in air indicated that the (101 diffraction peaks shifted from 25.78° to 25.05° for annealed Ti-Nb-Zr-O samples with different Zr contents because of larger lattice parameter of Ti-Nb-Zr-O compared to that of undoped TiO2.

  19. Thermodynamic description of the Ta-W-Zr system

    Guo, Cuiping; Li, Changrong; Du, Zhenmin; Shang, Shunli

    2014-01-01

    The Ta-W, W-Zr and Ta-W-Zr systems are critically reviewed and modeled using the CALPHAD technique. The enthalpy of formation of the stoichiometric compound W 2 Zr in the W-Zr system is predicted from first-principles calculations. The solution phases (liquid, bcc and hcp) are modeled by the substitutional solution model. The compound W 2 Zr is treated with the formula (Ta,W) 2 Zr in the Ta-W-Zr system because of a significant solid solubility of Ta in W 2 Zr. All experimental data, including the Gibbs energy of formation, enthalpy of formation, activity of Ta and W of bcc phase at 1 200 K, Ta-W and W-Zr phase diagrams, and three isothermal sections of the Ta-W-Zr system at 1 073, 1 098, and 1 873 K, are reproduced in the present work. A set of self-consistent thermodynamic parameters of the Ta-W-Zr system is obtained.

  20. Synthesis of ZrO2 nanoparticles by hydrothermal treatment

    Machmudah, Siti; Widiyastuti, W.; Prastuti, Okky Putri; Nurtono, Tantular; Winardi, Sugeng; Wahyudiono,; Kanda, Hideki; Goto, Motonobu

    2014-01-01

    Zirconium oxide (zirconia, ZrO 2 ) is the most common material used for electrolyte of solid oxide fuel cells (SOFCs). Zirconia has attracted attention for applications in optical coatings, buffer layers for growing superconductors, thermal-shield, corrosion resistant coatings, ionic conductors, and oxygen sensors, and for potential applications including transparent optical devices and electrochemical capacitor electrodes, fuel cells, catalysts, and advanced ceramics. In this work, zirconia particles were synthesized from ZrCl 4 precursor with hydrothermal treatment in a batch reactor. Hydrothermal treatment may allow obtaining nanoparticles and sintered materials with controlled chemical and structural characteristics. Hydrothermal treatment was carried out at temperatures of 150 – 200°C with precursor concentration of 0.1 – 0.5 M. Zirconia particles obtained from this treatment were analyzed by using SEM, PSD and XRD to characterize the morphology, particle size distribution, and crystallinity, respectively. Based on the analysis, the size of zirconia particles were around 200 nm and it became smaller with decreasing precursor concentration. The increasing temperature caused the particles formed having uniform size. Zirconia particles formed by hydrothermal treatment were monoclinic, tetragonal and cubic crystal

  1. Superconducting properties of amorphous Zr-Ge binary alloys

    Inoue, A.; Takahashi, Y.; Toyota, N.; Fukase, T.; Masumoto, T.

    1982-01-01

    A new type of refractory metal-metalloid amorphous alloys exhibiting superconductivity has been found in a binary Zr-Ge system by a modified melt-spinning technique. Specimens are in the form of continuous ribbons 1 to 2 mm wide and 0.02 to 0.03 mm thick. The germanium content in the amorphous alloys is limited to the range of 13 to 21 at%. These amorphous alloys are so ductile that no cracks are observed even after closely contacted bending test. Data are reported for various alloy compositions for the Vickers hardness and crystallization temperature, the tensile fracture strength, superconducting transition temperature Tsub(c), upper critical magnetic field, critical current density in the absence of an applied field, upper critical field gradient at Tsub(c) and the electrical resistivity at 4.2 K. The Ginzburg-Landau (GL) parameter and the GL coherence length were estimated to be 72 to 111 and about 7.9 nm, respectively, from these experimental values by using the Ginzburg-Landau-Abrikosov-Gorkov theory and hence it is concluded that the Zr-Ge amorphous alloys are extremely 'soft' type-II superconductor with high degree of dirtiness which possesses the Tsub(c) values higher than zirconium metal, in addition to high strength combined with good ductility. (author)

  2. Study on direct dissolution of U-10Zr alloy and distribution of uranium and zirconium in liquid cadmium

    Ye Yuxing; Gao Yuan

    1997-09-01

    The effect of dissolution time, temperature, total surface area of U-10Zr alloy pellets and stirring on the dissolution and dissolution rate of uranium in liquid cadmium were studied. Cadmium containing U and Zr dissolved from U-10Zr alloy at 475 degree C and 500 degree C respectively was analyzed with electron microanalyzer. The experimental results show that at 400 degree and 500 degree C with the stirring rate of some 150 r/min, the solubilities of uranium in liquid cadmium are 0.4% and 2.2%, respectively. At the first 30 min, the dissolution rates of U-10Zr alloy pellets are 0.05 g/(cm 2 ·h) and 0.32 g/(cm 2 ·h), respectively. The suitable dissolution conditions for U-10Zr alloy pellets in liquid cadmium (the ratio of the mass of liquid cadmium to that of the pellets ≅7) are: temperature, about 480 degree C; stirring rate, about 150 r/min; dissolution time, 4 h. The distribution of uranium and zirconium in cadmium is homogeneous

  3. The Effect of Ag Addition on the Enhancement of the Thermal and Mechanical Properties of CuZrAl Bulk Metallic Glasses

    Tsan-Man Chung

    2016-09-01

    Full Text Available In this study, the thermal and mechanical properties of Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 bulk metallic glasses (BMGs are investigated by using an X-ray diffractometer (XRD, a differential scanning calorimeter (DSC, differential thermal analysis (DTA, a Vickers hardness tester, a material test system (MTS, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 BMGs were made by arc-melting and an injection casting process. The results revealed that the glass transition temperature (Tg and the crystallization temperature (Tx of CuZrAl alloy decreased with the Ag addition. Hence, the supercooled liquid region and γ of Cu45Zr43Al7Ag5 alloy increased to 76 K and 0.42, respectively. The thermal stability and glass forming ability of CuZrAlAg BMG alloys were enhanced by the microalloyed Ag content. The room temperature compressive fracture strength and strain measured of Cu47Zr43Al7Ag3 were about 2200 MPa and 2.1%, respectively. The distribution of vein patterns and the formation of nanocrystalline phases on the fracture surface of Cu47Zr43Al7Ag3 alloy can be observed by SEM and TEM to be significant, indicating a typical ductile fracture behavior and an improved plasticity of alloys with the addition of microalloyed Ag from 0 to 6 atom %.

  4. High throughput exploration of Zr{sub x}Si{sub 1−x}O{sub 2} dielectrics by evolutionary first-principles approaches

    Zhang, Jin [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2100 (United States); Zeng, Qingfeng, E-mail: qfzeng@nwpu.edu.cn [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Oganov, Artem R. [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2100 (United States); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Dong, Dong; Liu, Yunfang [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China)

    2014-11-07

    The high throughput approaches aim to discover, screen and optimize materials in a cost-effective way and to shorten their time-to-market. However, computational approaches typically involve a combinatorial explosion problem, to deal with which, we adopted hybrid evolutionary algorithms together with first-principle calculations to explore possible stable and metastable crystal structures of ZrO{sub 2}–SiO{sub 2} dielectrics. The calculation reproduced two already known structures (I4{sub 1}/amd-ZrSiO{sub 4} and I4{sub 1}/a-ZrSiO{sub 4}) and predicted two new thermodynamically metastable structures Zr{sub 3}SiO{sub 8} (P4{sup ¯}3m) and ZrSi{sub 2}O{sub 6} (P3{sup ¯}1m). At ambient pressure, the only thermodynamically stable zirconium silicate is I4{sub 1}/amd-ZrSiO{sub 4} (zircon). Dynamical stability of the new phases has been verified by phonon calculations, and their static dielectric constants are higher than that of the known phases of ZrSiO{sub 4}. Band structure, density of state, electron localization function and Bader charges are presented and discussed. The new metastable structures are insulators with the DFT band gaps of 3.65 and 3.52 eV, respectively. Calculations show that P4{sup ¯}3m-Zr{sub 3}SiO{sub 8} has high dielectric constant (∼20.7), high refractive index (∼2.4) and strong dispersion of light. Global optimization of the dielectric fitness (electric energy density) shows that among crystalline phases of ZrO{sub 2}–SiO{sub 2}, maximum occurs for I4{sub 1}/a-ZrSiO{sub 4}. - Highlights: • Two new thermodynamically metastable ZrO{sub 2}–SiO{sub 2} compounds are predicted. • The predicated P-43m or P4{sup ¯}3m-Zr{sub 3}SiO{sub 8} has the highest dielectric constant and refractive index. • I4{sub 1}/a-ZrSiO{sub 4} shows the highest electric energy density among ZrO{sub 2}–SiO{sub 2} dielectrics.

  5. Behaving safely under pressure: The effects of job demands, resources, and safety climate on employee physical and psychosocial safety behavior.

    Bronkhorst, Babette

    2015-12-01

    Previous research has shown that employees who experience high job demands are more inclined to show unsafe behaviors in the workplace. In this paper, we examine why some employees behave safely when faced with these demands while others do not. We add to the literature by incorporating both physical and psychosocial safety climate in the job demands and resources (JD-R) model and extending it to include physical and psychosocial variants of safety behavior. Using a sample of 6230 health care employees nested within 52 organizations, we examined the relationship between job demands and (a) resources, (b) safety climate, and (c) safety behavior. We conducted multilevel analyses to test our hypotheses. Job demands (i.e., work pressure), job resources (i.e., job autonomy, supervisor support, and co-worker support) and safety climate (both physical and psychosocial safety climate) are directly associated with, respectively, lower and higher physical and psychosocial safety behavior. We also found some evidence that safety climate buffers the negative impact of job demands (i.e., work-family conflict and job insecurity) on safety behavior and strengthens the positive impact of job resources (i.e., co-worker support) on safety behavior. Regardless of whether the focus is physical or psychological safety, our results show that strengthening the safety climate within an organization can increase employees' safety behavior. Practical implication: An organization's safety climate is an optimal target of intervention to prevent and ameliorate negative physical and psychological health and safety outcomes, especially in times of uncertainty and change. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

  6. Microstructural evolution of the system Ni-ZrO{sub 2}-SiO{sub 2} synthesized by the sol-gel process

    Garcia Murillo, A., E-mail: angarciam@ipn.m [Instituto Politecnico Nacional, CICATA Unidad Altamira, Km. 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamaulipas (Mexico); Instituto Politecnico Nacional, CIITEC, Cerrada CECATI S/N Col. Sta. Catarina, Del. Azcapotzalco, Mexico D.F. 02250 (Mexico); Carrillo Romo, F. de J. [Instituto Politecnico Nacional, CICATA Unidad Altamira, Km. 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamaulipas (Mexico); Instituto Politecnico Nacional, CIITEC, Cerrada CECATI S/N Col. Sta. Catarina, Del. Azcapotzalco, Mexico D.F. 02250 (Mexico); Torres Huerta, A.M.; Dominguez Crespo, M.A.; Ramirez Meneses, E. [Instituto Politecnico Nacional, CICATA Unidad Altamira, Km. 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamaulipas (Mexico); Terrones, H. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055. Colonia Lomas 4 seccion S.L.P. (Mexico); Flores Vela, A. [Instituto Politecnico Nacional, CICATA Unidad Altamira, Km. 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamaulipas (Mexico)

    2010-04-16

    The analysis of the structural changes corresponding with composition and temperature is fundamental for understanding the applications of ceramic glass. In particular, the system ZrO{sub 2}-SiO{sub 2} is commonly used in the ceramic industry due to the high chemical stability and superior resistance for dissolution during firing in glazes. This work is focused on the synthesis of Ni doped ZrO{sub 2}-SiO{sub 2} powders with different Zr:Si molar ratios (20:80, 50:50 and 70:30) by sol-gel process. For purposes of comparison, un-doped ZrO{sub 2}-SiO{sub 2} systems were also prepared. TEOS, zirconium propoxide and nickel chloride hexahydrate were used as precursors of the SiO{sub 2}, ZrO{sub 2} and ion dopant, respectively. The obtained xerogels were thermally treated from 300 to 1300 {sup o}C in order to follow their structural evolution. FT-IR results show the corresponding bands of the M-O bonds related to the formation of zircon at high temperatures, while XRD analyses display t-ZrO{sub 2} with traces of m-ZrO{sub 2} at the evaluated temperatures; also, between 1200 and 1300 {sup o}C, the zircon compound (ZrSiO{sub 4}) was detected. It was observed that inserting nickel as a dopant has a significant effect on the structural and morphological characteristics. From the comparison of the doped and un-doped specimens, we hypothesize that the presence of Ni and the heat treatment promote the stabilization and crystallization of the zircon phase at molar ratios higher than 50Zr:50Si, or Ni is incorporating into the ZrO{sub 2} phase, provoking oxygen vacancies and leading to tetragonal phase stabilization.

  7. Study on technology for laboratory scale production of Zirconium Chloride (ZrCl4) by chlorinating Zirconium dioxide (ZrO2)

    Nguyen Van Sinh

    2007-01-01

    ZrCl 4 is used as a main material for producing metallic zirconium. There are four methods for obtaining ZrCl 4 . The method of chlorination of ZrO 2 was selected and some instruments have been made for the study (to produce ZrCl 4 in laboratory scale). A procedure of preparing ZrCl 4 on the obtained instruments was set up and a small amount of ZrCl 4 was successfully obtained. (author)

  8. Mechanical and electrochemical characterization of Ti-12Mo-5Zr alloy for biomedical application

    Zhao Changli; Zhang Xiaonong; Cao Peng

    2011-01-01

    Highlights: → A new β metastable titanium alloy with composition of Ti-12Mo-5Zr that comprised of non-toxic elements Mo and Zr has been developed. → The elastic modulus of the Ti-12Mo-5Zr alloy is as low as 64 GPa, which is much lower than those of pure Ti and Ti-6Al-4V alloy. → The Ti-12Mo-5Zr alloy has moderate strength and much higher microhardness as compared with Ti-6Al-4V, which showing better mechanical biocompatibility. → The corrosion resistance is much higher than that of Ti-6Al-4V in a simulated body fluid (Hank's solution). - Abstract: We have fabricated a new β metastable titanium alloy that comprised of non-toxic elements Mo and Zr. Ingot with composition of Ti-12Mo-5Zr is prepared by melting pure metals in a vacuum non-consumable arc melting furnace. The alloy is then homogenized and solution treated under different temperature. The alloy is characterized by optical microscopy, X-ray diffraction, tensile tests and found to have an acicular martensitic α'' + β structure and dominant β phase for the 1053 K and 1133 K solution treatment samples, respectively. The elastic modulus of the latter is about 64 GPa, which is much lower than those of pure Ti and Ti-6Al-4V alloy. In addition, it had moderate strength and much higher microhardness as compared with Ti-6Al-4V alloy. The results show better mechanical biocompatibility of this alloy, which will avoid stress shielding and thus prevent bone resorption in orthopedic implants applications. As long-term stability in biological environment is required, we have also evaluated the electrochemical behavior in a simulated body fluid (Hank's solution). Potentiodynamic polarization curves exhibits that the 1133 K solution treatment Ti-12Mo-5Zr sample has better corrosion properties than Ti-6Al-4V and is comparable to the pure titanium. The good corrosion resistance combined with better mechanical biocompatibility makes the Ti-12Mo-5Zr alloy suitable for use as orthopedic implants.

  9. The embodiment of tourism among bisexually-behaving Dominican male sex workers.

    Padilla, Mark B

    2008-10-01

    While theories of "structure" and social inequality have increasingly informed global health efforts for HIV prevention--with growing recognition of the linkages between large-scale political and economic factors in the distribution and impact of the HIV/AIDS epidemic--there is still little theorization of precisely how structural factors shape the very bodies and sexualities of specific populations and groups. In order to extend the theoretical understanding of these macro-micro linkages, this article examines how the growth of the tourism industry in the Dominican Republic has produced sexual practices and identities that reflect both the influence of large-scale structural processes and the resistant responses of local individuals. Drawing on social science theories of political economy, embodiment, and authenticity, I argue that an understanding of patterns of sexuality and HIV risk in the region requires analysis of how political-economic transformations related to tourism intersect with the individual experiences and practices of sexuality on the ground. The analysis draws on long-term ethnographic research with bisexually behaving male sex workers in two cities in the Dominican Republic, including participant observation, in-depth interviews, focus groups, and surveys. By examining the global and local values placed on these men's bodies and the ways sex workers use their bodies to broker tourists' pleasure, we may better understand how the large-scale structures of the tourism industry are linked to the specific meanings and practices of sexuality.

  10. Social class, power, and selfishness: when and why upper and lower class individuals behave unethically.

    Dubois, David; Rucker, Derek D; Galinsky, Adam D

    2015-03-01

    Are the rich more unethical than the poor? To answer this question, the current research introduces a key conceptual distinction between selfish and unethical behavior. Based on this distinction, the current article offers 2 novel findings that illuminate the relationship between social class and unethical behavior. First, the effects of social class on unethical behavior are not invariant; rather, the effects of social class are moderated by whether unethical behavior benefits the self or others. Replicating past work, social class positively predicted unethical behavior; however, this relationship was only observed when that behavior was self-beneficial. When unethical behavior was performed to benefit others, social class negatively predicted unethical behavior; lower class individuals were more likely than upper class individuals to engage in unethical behavior. Overall, social class predicts people's tendency to behave selfishly, rather than predicting unethical behavior per se. Second, individuals' sense of power drove the effects of social class on unethical behavior. Evidence for this relationship was provided in three forms. First, income, but not education level, predicted unethical behavior. Second, feelings of power mediated the effect of social class on unethical behavior, but feelings of status did not. Third, two distinct manipulations of power produced the same moderation by self-versus-other beneficiary as was found with social class. The current theoretical framework and data both synthesize and help to explain a range of findings in the social class and power literatures. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  11. Solving the economic dispatch problem with a modified quantum-behaved particle swarm optimization method

    Sun Jun; Fang Wei; Wang Daojun; Xu Wenbo

    2009-01-01

    In this paper, a modified quantum-behaved particle swarm optimization (QPSO) method is proposed to solve the economic dispatch (ED) problem in power systems, whose objective is to simultaneously minimize the generation cost rate while satisfying various equality and inequality constraints. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability of the algorithm. Many nonlinear characteristics of the generator, such as ramp rate limits, prohibited operating zones, and nonsmooth cost functions are considered when the proposed method is used in practical generator operation. The feasibility of the QPSO-DM method is demonstrated by three different power systems. It is compared with the QPSO, the differential evolution (DE), the particle swarm optimization (PSO), and the genetic algorithm (GA) in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed QPSO-DM method is able to obtain higher quality solutions stably and efficiently in the ED problem than any other tested optimization algorithm.

  12. Solving the economic dispatch problem with a modified quantum-behaved particle swarm optimization method

    Jun Sun; Wei Fang; Daojun Wang; Wenbo Xu [School of Information Technology, Jiangnan Univ., Wuxi, Jiangsu 214122 (China)

    2009-12-15

    In this paper, a modified quantum-behaved particle swarm optimization (QPSO) method is proposed to solve the economic dispatch (ED) problem in power systems, whose objective is to simultaneously minimize the generation cost rate while satisfying various equality and inequality constraints. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability of the algorithm. Many nonlinear characteristics of the generator, such as ramp rate limits, prohibited operating zones, and nonsmooth cost functions are considered when the proposed method is used in practical generator operation. The feasibility of the QPSO-DM method is demonstrated by three different power systems. It is compared with the QPSO, the differential evolution (DE), the particle swarm optimization (PSO), and the genetic algorithm (GA) in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed QPSO-DM method is able to obtain higher quality solutions stably and efficiently in the ED problem than any other tested optimization algorithm. (author)

  13. How Do Children Behave Regarding Their Birth Order in Dental Setting?

    Ghaderi, Faezeh; Fijan, Soleiman; Hamedani, Shahram

    2015-12-01

    Prediction of child cooperation level in dental setting is an important issue for a dentist to select the proper behavior management method. Many psychological studies have emphasized the effect of birth order on patient behavior and personality; however, only a few researches evaluated the effect of birth order on child's behavior in dental setting. This study was designed to evaluate the influence of children ordinal position on their behavior in dental setting. A total of 158 children with at least one primary mandibular molar needing class I restoration were selected. Children were classified based on the ordinal position; first, middle, or last child as well as single child. A blinded examiner recorded the pain perception of children during injection based on Visual Analogue Scale (VAS) and Sound, Eye and Movement (SEM) scale. To assess the child's anxiety, the questionnaire known as "Dental Subscale of the Children's Fear Survey Schedule" (CFSS-DS) was employed. The results showed that single children were significantly less cooperative and more anxious than the other children (p<0.001). The middle children were significantly more cooperative in comparison with the other child's position (p< 0.001). Single child may behave less cooperatively in dental setting. The order of child birth must also be considered in prediction of child's behavior for behavioral management.

  14. Dopamine Modulates Delta-Gamma Phase-Amplitude Coupling in the Prefrontal Cortex of Behaving Rats

    Andino-Pavlovsky, Victoria; Souza, Annie C.; Scheffer-Teixeira, Robson; Tort, Adriano B. L.; Etchenique, Roberto; Ribeiro, Sidarta

    2017-01-01

    Dopamine release and phase-amplitude cross-frequency coupling (CFC) have independently been implicated in prefrontal cortex (PFC) functioning. To causally investigate whether dopamine release affects phase-amplitude comodulation between different frequencies in local field potentials (LFP) recorded from the medial PFC (mPFC) of behaving rats, we used RuBiDopa, a light-sensitive caged compound that releases the neurotransmitter dopamine when irradiated with visible light. LFP power did not change in any frequency band after the application of light-uncaged dopamine, but significantly strengthened phase-amplitude comodulation between delta and gamma oscillations. Saline did not exert significant changes, while injections of dopamine and RuBiDopa produced a slow increase in comodulation for several minutes after the injection. The results show that dopamine release in the medial PFC shifts phase-amplitude comodulation from theta-gamma to delta-gamma. Although being preliminary results due to the limitation of the low number of animals present in this study, our findings suggest that dopamine-mediated modification of the frequencies involved in comodulation could be a mechanism by which this neurotransmitter regulates functioning in mPFC. PMID:28536507

  15. Seeing the whole picture: A comprehensive imaging approach to functional mapping of circuits in behaving zebrafish.

    Feierstein, C E; Portugues, R; Orger, M B

    2015-06-18

    In recent years, the zebrafish has emerged as an appealing model system to tackle questions relating to the neural circuit basis of behavior. This can be attributed not just to the growing use of genetically tractable model organisms, but also in large part to the rapid advances in optical techniques for neuroscience, which are ideally suited for application to the small, transparent brain of the larval fish. Many characteristic features of vertebrate brains, from gross anatomy down to particular circuit motifs and cell-types, as well as conserved behaviors, can be found in zebrafish even just a few days post fertilization, and, at this early stage, the physical size of the brain makes it possible to analyze neural activity in a comprehensive fashion. In a recent study, we used a systematic and unbiased imaging method to record the pattern of activity dynamics throughout the whole brain of larval zebrafish during a simple visual behavior, the optokinetic response (OKR). This approach revealed the broadly distributed network of neurons that were active during the behavior and provided insights into the fine-scale functional architecture in the brain, inter-individual variability, and the spatial distribution of behaviorally relevant signals. Combined with mapping anatomical and functional connectivity, targeted electrophysiological recordings, and genetic labeling of specific populations, this comprehensive approach in zebrafish provides an unparalleled opportunity to study complete circuits in a behaving vertebrate animal. Copyright © 2014. Published by Elsevier Ltd.

  16. Glomerular barrier behaves as an atomically precise bandpass filter in a sub-nanometre regime

    Du, Bujie; Jiang, Xingya; Das, Anindita; Zhou, Qinhan; Yu, Mengxiao; Jin, Rongchao; Zheng, Jie

    2017-11-01

    The glomerular filtration barrier is known as a 'size cutoff' slit, which retains nanoparticles or proteins larger than 6-8 nm in the body and rapidly excretes smaller ones through the kidneys. However, in the sub-nanometre size regime, we have found that this barrier behaves as an atomically precise 'bandpass' filter to significantly slow down renal clearance of few-atom gold nanoclusters (AuNCs) with the same surface ligands but different sizes (Au18, Au15 and Au10-11). Compared to Au25 (∼1.0 nm), just few-atom decreases in size result in four- to ninefold reductions in renal clearance efficiency in the early elimination stage, because the smaller AuNCs are more readily trapped by the glomerular glycocalyx than larger ones. This unique in vivo nano-bio interaction in the sub-nanometre regime also slows down the extravasation of sub-nanometre AuNCs from normal blood vessels and enhances their passive targeting to cancerous tissues through an enhanced permeability and retention effect. This discovery highlights the size precision in the body's response to nanoparticles and opens a new pathway to develop nanomedicines for many diseases associated with glycocalyx dysfunction.

  17. Charging and switching of ferroelectrets: how much can ferroelectrets behave like ferroelectrics?

    Schwoediauer, R.; Graz, I.; Bauer, S.

    2004-01-01

    Dielectrics with good charge storage capability, so called charge electrets, are non or weakly-polar materials. Despite their non-polar nature porous charge electrets with internally charged surfaces can exhibit very pronounced piezoelectricity. Such systems have been termed 'ferroelectrets' and they have been receiving growing attention over the last few years. Their puzzling and unexpected features resemble very much those normally known from traditional ferroelectrics: ferroelectrets are piezo- and pyroelectric, their polarization can be reversed by means of an external field and electrical as well as mechanical hysteresis loops were observed. As conventional ferroelectrics are different and more complicated than ferromagnets, so are ferroelectrets different and more complex than most ferroelectrics. Here we report about the very different charging and switching mechanism in ferroelectrets, both in simple model-systems and in less simple foam structures. These mechanisms are crucial and form the basis for the striking phenomenological similarities to ferroelectrics. We also want to address some of the specific peculiarities and pitfalls related to present ferroelectrets and their characterization. Interfacial charge injection at high electric fields and anelastic non-linearities, for instance, can be the cause for false ferroelectric-like hysteresis effects which do not reflect any polarization reversal. Our contribution is an attempt towards a more comprehensive picture of how much ferroelectrets behave like ferroelectrics. (author)

  18. A mathematical model for pressure-based organs behaving as biological pressure vessels.

    Casha, Aaron R; Camilleri, Liberato; Gauci, Marilyn; Gatt, Ruben; Sladden, David; Chetcuti, Stanley; Grima, Joseph N

    2018-04-26

    We introduce a mathematical model that describes the allometry of physical characteristics of hollow organs behaving as pressure vessels based on the physics of ideal pressure vessels. The model was validated by studying parameters such as body and organ mass, systolic and diastolic pressures, internal and external dimensions, pressurization energy and organ energy output measurements of pressure-based organs in a wide range of mammals and birds. Seven rules were derived that govern amongst others, lack of size efficiency on scaling to larger organ sizes, matching organ size in the same species, equal relative efficiency in pressurization energy across species and direct size matching between organ mass and mass of contents. The lung, heart and bladder follow these predicted theoretical relationships with a similar relative efficiency across various mammalian and avian species; an exception is cardiac output in mammals with a mass exceeding 10kg. This may limit massive body size in mammals, breaking Cope's rule that populations evolve to increase in body size over time. Such a limit was not found in large flightless birds exceeding 100kg, leading to speculation about unlimited dinosaur size should dinosaurs carry avian-like cardiac characteristics. Copyright © 2018. Published by Elsevier Ltd.

  19. Atomic-scale microstructures of Zr2Al3C4 and Zr3Al3C5 ceramics

    Lin, Z.J.; Zhuo, M.J.; He, L.F.; Zhou, Y.C.; Li, M.S.; Wang, J.Y.

    2006-01-01

    The microstructures of bulk Zr 2 Al 3 C 4 and Zr 3 Al 3 C 5 ceramics have been investigated using transmission electron microscopy and scanning transmission electron microscopy. These two carbides were determined to have a point group 6/mmm and a space group P6 3 /mmc using selected-area electron diffraction and convergent beam electron diffraction. The atomic-scale microstructures of Zr 2 Al 3 C 4 and Zr 3 Al 3 C 5 were investigated through high-resolution imaging and Z-contrast imaging. Furthermore, intergrowth between Zr 2 Al 3 C 4 and Zr 3 Al 3 C 5 was identified. Stacking faults in Zr 3 Al 3 C 5 were found to result from the insertion of an additional Zr-C layer. Cubic ZrC was occasionally identified to be incorporated in elongated Zr 3 Al 3 C 5 grains. In addition, Al may induce a twinned ZrC structure and lead to the formation of ternary zirconium aluminum carbides

  20. Correlation between structural relaxation enthalpy and superconducting properties of amorphous Zr70Cu30 and Zr70Ni30 alloys

    Inoue, A.; Matsuzaki, K.; Toyota, N.; Chen, H.S.; Masumoto, T.; Fukase, T.

    1985-01-01

    The anneal-induced change in the superconducting properties together with the irrecoverable relaxation enthalpy (ΔHsub(i,exo)) and recoverable relaxation enthalpy (ΔHsub(r,endo)) of amorphous Zr 70 Cu 30 and Zr 70 Ni 30 alloys was examined. The increase in ΔHsub(i,exo) and the degradation of Tsub(c) progress logarithmically with annealing time tsub(a) in a temperature range of 373 to 523 K. The activation energy and the attempted frequency were respectively estimated to be 1.5 eV and 6.6 x 10 13 sec -1 for the increase in ΔHsub(i,exo) and 1.5 eV and 1.9 x 10 14 sec -1 for the degradation of Tsub(c). The recoverable structure relaxation exerts little effect on Tsub(c). Based on the agreement between the kinetic parameters for the changes of ΔHsub(i,exo) and Tsub(c), it appears that the degradation of Tsub(c) on annealing is associated with the irrecoverable structural relaxation as a result of the annihilation of frozen-in defects and the topological and compositional atomic rearrangement. The values of the attempted frequency being of the order of Debye frequency suggest that the irrecoverable structural relaxation processes occur more or less independently from each other. (author)

  1. The preparation of Zr-deuteride and phase stability studies of the Zr-D system

    Maimaitiyili, T., E-mail: tuerdi.maimaitiyili@mah.se [Materials Science and Applied Mathematics, Malmö University, Nordenskiöldsgatan 1, 20506 Malmö (Sweden); Steuwer, A. [Nelson Mandela Metropolitan University, Gardham Avenue, 6031 Port Elizabeth (South Africa); Bjerkén, C.; Blomqvist, J. [Materials Science and Applied Mathematics, Malmö University, Nordenskiöldsgatan 1, 20506 Malmö (Sweden); Hoelzel, M. [Forschungsneutronenquelle Heinz-Maier-Leibnitz (FRM II), Technische Universität Muünchen, Lichtenbergstr. 1, D-85747 Garching (Germany); Ion, J.C. [Materials Science and Applied Mathematics, Malmö University, Nordenskiöldsgatan 1, 20506 Malmö (Sweden); Zanellato, O. [PIMM, Ensam - Cnam - CNRS, 151 Boulevard de l' Hôpital, 75013 Paris (France)

    2017-03-15

    Deuteride phases in the zirconium-deuterium system in the temperature range 25–286 °C have been studied in-situ by high resolution neutron diffraction. The study primarily focused on observations of δ→γ transformation at 180 °C, and the peritectoid reaction α + δ ↔ γ at 255 °C in commercial grade Zr powder that was deuterated to a deuterium/Zr ratio of one to one. A detailed description of the zirconium deuteride preparation route by high temperature gas loading is also described. The lattice parameters of α-Zr, δ-ZrD{sub x} and ε-ZrD{sub x} were determined by whole pattern crystal structure analysis, using Rietveld and Pawley refinements, and are in good agreement with values reported in the literature. The controversial γ-hydride phase was observed both in-situ and ex-situ in deuterated Zr powder after a heat treatment at 286 °C and slow cooling. - Highlights: • Controversial γ phase observed both in-situ and ex-situ after heat treatments. • γ-ZrD is observed at room temperature after 5 h of heat treatment at 286 °C. • Presence of α + δ ↔ γ at 255 °C was not observed. • It was observed that there is a δ → γ transformation present around 150 °C.

  2. Observations of a Cast Cu-Cr-Zr Alloy

    Ellis, David L.

    2006-01-01

    Prior work has demonstrated that Cu-Cr-Nb alloys have considerable advantages over the copper alloys currently used in regeneratively cooled rocket engine liners. Observations indicated that Zr and Nb have similar chemical properties and form very similar compounds. Glazov and Zakharov et al. reported the presence of Cr2Zr in Cu-Cr-Zr alloys with up to 3.5 wt% Cr and Zr though Zeng et al. calculated that Cr2Zr could not exist in a ternary Cu-Cr-Zr alloy. A cast Cu-6.15 wt% Cr-5.25 wt% Zr alloy was examined to determine if the microstructure developed would be similar to GRCop-84 (Cu-6.65 wt% Cr-5.85 wt% Nb). It was observed that the Cu-Cr-Zr system did not form any Cr2Zr even after a thermal exposure at 875 C for 176.5 h. Instead the alloy consisted of three phases: Cu, Cu5Zr, and Cr.

  3. Study of microstructure evolution and strengthening mechanisms in novel TiZrAlB alloy

    Liu, S.G.; Feng, Z.H.; Xia, C.Q.; Zhang, Z.G.; Zhang, X.; Zhang, X.Y., E-mail: xyzhang@ysu.edu.cn; Ma, M.Z.; Liu, R.P., E-mail: riping@ysu.edu.cn

    2017-04-24

    In this paper, the microstructural evolution and mechanical properties of the as-cast Ti-χZr-4Al-0.005B (TχZAB and χ=0, 10, 20, 30, 40 wt%) alloys were systematically investigated. Only the α phase was detected from the X-ray diffraction patterns of the as-cast TχZAB quaternary alloy series. As the Zr content increased, the average size and length-diameter ratio of the α grains were decreased from 69.8 μm to 17.1 µm and 37.5 to 8.4, respectively. The analysis of the results from the tensile and microhardness tests demonstrated that both the strength and hardness increased significantly as the Zr content increased (from 0 wt% to 40 wt%). Nevertheless, the ductility exhibited an opposite trend. The fracture mode of the ductile-brittle transfer was consistent with the ductility alteration. The as-cast Ti-40Zr-4Al-0.005B alloys demonstrated the highest tensile strength (σ{sub b}=1134 MPa), which increased by 53% compared to the Ti-4Al-0.005B alloys, whereas the lowest elongation-to-failure was of 6.77%. The mechanical properties of the TχZAB alloy series were discussed based on the microstructural evolution and the solid solution strengthening mechanisms.

  4. Diffusion of hydrogen interstitials in Zr based AB2 and mischmetal based AB5 alloys

    Mani, N; Ravi, N; Ramaprabhu, S

    2005-01-01

    The Zr based AB 2 alloys ZrMnFe 0.5 Ni 0.5 , ZrMnFe 0.5 Co 0.5 and mischmetal (Mm) based AB 5 alloy MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 have been prepared and characterized by means of powder x-ray diffractograms. The hydrogen absorption kinetics of these alloys have been studied in the temperature and pressure ranges 450-650 0 C and 10-100 mbar respectively with a maximum H to host alloy formula unit ratio of 0.01, using a pressure reduction technique. The diffusion coefficient of the hydrogen interstitials has been determined from hydrogen absorption kinetics experiments. The dependence of the diffusion coefficient on the alloy content has been discussed. For Mm based MmNi 3.5 Al 0.5 Fe 0.5 Co 0.5 alloy, the diffusion coefficient is about an order of magnitude higher than that of the Zr based alloys

  5. Decomposition of the γ phase in as-cast and quenched U–Zr alloys

    Irukuvarghula, S., E-mail: sandeep.irukuvarghula@manchester.ac.uk [Department of Nuclear Engineering, Texas A& M University, College Station (United States); School of Materials, University of Manchester (United Kingdom); Ahn, Sangjoon [Department of Nuclear Engineering, Texas A& M University, College Station (United States); Department of Mechanical and Nuclear Engineering, UNIST (Korea, Republic of); McDeavitt, S.M. [Department of Nuclear Engineering, Texas A& M University, College Station (United States)

    2016-05-15

    An investigation of the decomposition of the high temperature γ phase in as-cast and quenched U–Zr alloys was conducted. Differential scanning calorimetry data clearly showed δ⇌γ transformations in alloys with <10 wt% Zr while XRD data did not contain any peaks which uniquely identify it's presence. Since δ phase forms via ω transformation, a comparison of the theoretical diffraction patterns for ω and δ revealed that the intensities of the peaks which uniquely identify the existence of δ when α-U is present, were either very weak, or were zero in ω, suggesting that the ambiguity can be explained if the phase present in these alloys is ω as opposed to δ. Our data are consistent with the presence of δ and ω in as-cast and quenched U–50Zr alloy, respectively, and (α + ω) in rest of the as-cast and quenched alloys. Based on the experimental data, the transformation sequence from γ phase in U–Zr alloys is proposed.

  6. Site-specifically {sup 89}Zr-labeled monoclonal antibodies for ImmunoPET

    Tinianow, Jeff N.; Gill, Herman S.; Ogasawara, Annie; Flores, Judith E.; Vanderbilt, Alexander N.; Luis, Elizabeth; Vandlen, Richard; Darwish, Martine; Junutula, Jagath R.; Williams, Simon-P. [Genentech Research and Early Development, Genentech Inc., South San Francisco, CA 94080 (United States); Marik, Jan [Genentech Research and Early Development, Genentech Inc., South San Francisco, CA 94080 (United States)], E-mail: marik.jan@gene.com

    2010-04-15

    Three thiol reactive reagents were developed for the chemoselective conjugation of desferrioxamine (Df) to a monoclonal antibody via engineered cysteine residues (thio-trastuzumab). The in vitro stability and in vivo imaging properties of site-specifically radiolabeled {sup 89}Zr-Df-thio-trastuzumab conjugates were investigated. Methods: The amino group of desferrioxamine B was acylated by bromoacetyl bromide, N-hydroxysuccinimidyl iodoacetate, or N-hydroxysuccinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate to obtain thiol reactive reagents bromoacetyl-desferrioxamine (Df-Bac), iodoacetyl-desferrioxamine (Df-Iac) and maleimidocyclohexyl-desferrioxamine (Df-Chx-Mal), respectively. Df-Bac and Df-Iac alkylated the free thiol groups of thio-trastuzumab by nucleophilic substitution forming Df-Ac-thio-trastuzumab, while the maleimide reagent Df-Chx-Mal reacted via Michael addition to provide Df-Chx-Mal-thio-trastuzumab. The conjugates were radiolabeled with {sup 89}Zr and evaluated for serum stability, and their positron emission tomography (PET) imaging properties were investigated in a BT474M1 (HER2-positive) breast tumor mouse model. Results: The chemoselective reagents were obtained in 14% (Df-Bac), 53% (Df-Iac) and 45% (Df-Chx-Mal) yields. Site-specific conjugation of Df-Chx-Mal to thio-trastuzumab was complete within 1 h at pH 7.5, while Df-Iac and Df-Bac respectively required 2 and 5 h at pH 9. Each Df modified thio-trastuzumab was chelated with {sup 89}Zr in yields exceeding 75%. {sup 89}Zr-Df-Ac-thio-trastuzumab and {sup 89}Zr-Df-Chx-Mal-thio-trastuzumab were stable in mouse serum and exhibited comparable PET imaging capabilities in a BT474M1 (HER2-positive) breast cancer model reaching 20-25 %ID/g of tumor uptake and a tumor to blood ratio of 6.1-7.1. Conclusions: The new reagents demonstrated good reactivity with engineered thiol groups of trastuzumab and very good chelation properties with {sup 89}Zr. The site-specifically {sup 89}Zr-labeled thio

  7. Tetherless near-infrared control of brain activity in behaving animals using fully implantable upconversion microdevices.

    Wang, Ying; Lin, Xudong; Chen, Xi; Chen, Xian; Xu, Zhen; Zhang, Wenchong; Liao, Qinghai; Duan, Xin; Wang, Xin; Liu, Ming; Wang, Feng; He, Jufang; Shi, Peng

    2017-10-01

    Many nanomaterials can be used as sensors or transducers in biomedical research and they form the essential components of transformative novel biotechnologies. In this study, we present an all-optical method for tetherless remote control of neural activity using fully implantable micro-devices based on upconversion technology. Upconversion nanoparticles (UCNPs) were used as transducers to convert near-infrared (NIR) energy to visible light in order to stimulate neurons expressing different opsin proteins. In our setup, UCNPs were packaged in a glass micro-optrode to form an implantable device with superb long-term biocompatibility. We showed that remotely applied NIR illumination is able to reliably trigger spiking activity in rat brains. In combination with a robotic laser projection system, the upconversion-based tetherless neural stimulation technique was implemented to modulate brain activity in various regions, including the striatum, ventral tegmental area, and visual cortex. Using this system, we were able to achieve behavioral conditioning in freely moving animals. Notably, our microscale device was at least one order of magnitude smaller in size (∼100 μm in diameter) and two orders of magnitude lighter in weight (less than 1 mg) than existing wireless optogenetic devices based on light-emitting diodes. This feature allows simultaneous implantation of multiple UCNP-optrodes to achieve modulation of brain function to control complex animal behavior. We believe that this technology not only represents a novel practical application of upconversion nanomaterials, but also opens up new possibilities for remote control of neural activity in the brains of behaving animals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Laying hens behave differently in artificially and naturally sourced ammoniated environments.

    Pokharel, B B; Dos Santos, V M; Wood, D; Van Heyst, B; Harlander-Matauschek, A

    2017-12-01

    Laying hens are chronically exposed to high levels of ammonia (NH3), one of the most abundant aerial pollutants in poultry houses. Tests for aversion to NH3 in laying hens have used artificially sourced NH3/air mixtures (i.e., from a gas cylinder) showing that birds prefer fresh air to NH3. However, artificially sourced NH3/air mixtures may not accurately reflect barn air conditions, where manure emits a variety of gases. Herein, we investigated whether laying hens differentiate between artificially and naturally sourced NH3/air mixtures and how exposure to NH3 affects foraging and aversive behavior. A total of 20 laying hens was exposed to artificially sourced [A] (from an anhydrous NH3 cylinder) and naturally sourced [N] (from conspecific laying hen excreta) gas mixtures. Hens were exposed to A and N mixtures with NH3 concentrations of 25 and 45 ppm, as well as fresh air [FA]. During the experiment, all birds were exposed to each treatment 3 times using a custom-built polycarbonate chamber, containing a foraging area (containing raisins, mealworms, and feed mix) and a gas delivery system. All testing sessions were video recorded, analyzed with INTERACT® software, and subjected to a GLIMMIX procedure in SAS. Our results showed that the laying hens spent less time foraging overall (P hens were more likely to forage for a longer time (with fewer interruptions) in N than in A treatments (P hens also reacted with greater aversion towards treatment A compared to treatment N (P hens of our study preferred fresh to ammoniated air and that they behaved differently in artificially and naturally sourced NH3/air mixtures, possibly due to the presence of familiar stimuli from the excreta. These findings have implications for new developments in methodological approaches for behavioral testing and for recommendations regarding NH3 levels inside poultry barns. © 2017 Poultry Science Association Inc.

  9. Head-mounted LED for optogenetic experiments of freely-behaving animal

    Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

    2016-03-01

    Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal

  10. Effects of minor Zr and Sr on as-cast microstructure and mechanical properties of Mg-3Ce-1.2Mn-0.9Sc (wt.%) magnesium alloy

    Pan Fusheng; Yang Mingbo; Shen Jia; Wu Lu

    2011-01-01

    Research highlights: → Minor Zr and/or Sr additions can effectively refine the grains of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the tensile properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. → Minor Zr and/or Sr additions can improve the creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. - Abstract: The effects of minor Zr and Sr on the as-cast microstructure and mechanical properties of the Mg-3Ce-1.2Mn-0.9Sc (wt.%) alloy were investigated by using optical and electron microscopies, differential scanning calorimetry (DSC) analysis, and tensile and creep tests. The results indicate that adding minor Zr and/or Sr to the Mg-3Ce-1.2Mn-0.9Sc alloy does not cause an obvious change in the morphology and distribution of the Mg 12 Ce phase. However, the grains of the Zr and/or Sr-containing alloys are effectively refined. Among the Zr and/or Sr-containing alloys, the grains of the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr are the finest, followed by the alloys with the additions of 0.5 wt.%Zr and 0.1 wt.%Sr, respectively. In addition, small additions of Zr and/or Sr can improve the tensile and creep properties of the Mg-3Ce-1.2Mn-0.9Sc alloy. Among the Zr and/or Sr-containing alloys, the alloy with the addition of 0.5 wt.%Zr + 0.1 wt.%Sr obtains the optimum tensile and creep properties.

  11. Two-Photon Functional Imaging of the Auditory Cortex in Behaving Mice: From Neural Networks to Single Spines

    Ruijie Li

    2018-04-01

    Full Text Available In vivo two-photon Ca2+ imaging is a powerful tool for recording neuronal activities during perceptual tasks and has been increasingly applied to behaving animals for acute or chronic experiments. However, the auditory cortex is not easily accessible to imaging because of the abundant temporal muscles, arteries around the ears and their lateral locations. Here, we report a protocol for two-photon Ca2+ imaging in the auditory cortex of head-fixed behaving mice. By using a custom-made head fixation apparatus and a head-rotated fixation procedure, we achieved two-photon imaging and in combination with targeted cell-attached recordings of auditory cortical neurons in behaving mice. Using synthetic Ca2+ indicators, we recorded the Ca2+ transients at multiple scales, including neuronal populations, single neurons, dendrites and single spines, in auditory cortex during behavior. Furthermore, using genetically encoded Ca2+ indicators (GECIs, we monitored the neuronal dynamics over days throughout the process of associative learning. Therefore, we achieved two-photon functional imaging at multiple scales in auditory cortex of behaving mice, which extends the tool box for investigating the neural basis of audition-related behaviors.

  12. Synthesis and characterization of a polyborosilazane/Cp2ZrCl2 hybrid precursor for the Si-B-C-N-Zr multinary ceramic.

    Long, Xin; Shao, Changwei; Wang, Hao; Wang, Jun

    2015-09-21

    A novel zirconium-contained polyborosilazane (PBSZ-Zr) was synthesized by chemical modification of a liquid polyborosilazane (LPBSZ) with Cp2ZrCl2. A Si-B-C-N-Zr multinary ceramic was prepared via pyrolysis of PBSZ-Zr. The properties and the ceramization process of PBSZ-Zr, as well as the microstructural development and properties of the derived SiBCN-Zr ceramic, were well studied. The active Si-H and N-H groups in LPBSZ react with Zr-Cl in Cp2ZrCl2 to form PBSZ-Zr polymers. The Zr content of the SiBCN-Zr ceramic was 3.39 wt% when the weight ratio of Cp2ZrCl2 to LPBSZ was 20 : 100. The SiBCN-Zr ceramic remains amorphous when pyrolyzed below 1600 °C, but the crystal phases of Zr2CN, ZrC, BN, SiC, and Si3N4 were detected from a 1600 °C treated sample. Due to the low activity of free carbon at the interface of the SiBCN-Zr ceramic, the oxidation resistance of the SiBCN-Zr ceramic under air was improved compared with the SiBCN ceramic.

  13. Diffusion of Ti in α-Zr single crystals

    Hood, G.M.; Zou, H.; Schultz, R.J.; Jackman, J.A.

    1994-11-01

    Ti diffusion coefficients (D) have been measured in nominally pure αZr single crystals (773-1124 K) in directions both parallel (D pa ) and perpendicular (D pe , few data) to the c-axis: tracer techniques and secondary ion mass spectrometry were used to determine the diffusion profiles. The results show a temperature dependence which suggests two regions of diffusion behaviour. Above 1035 K, region I, diffusion conforms to the expectations of intrinsic behaviour with normal Arrhenius law constants: D pa = 1.7 x 10 -3 exp(-2.93 ± 0.08 eV/kΤ) m 2 /s. Below 1035 K, region II, D's are enhanced with respect to an extrapolation of region I behaviour. The region II data are associated with extrinsic effects. (author). 13 refs., 1 tab., 3 figs

  14. Growth and microstructure formation of isothermally-solidified Zircaloy-4 joints brazed by a Zr-Ti-Cu-Ni amorphous alloy ribbon

    Kim, K. H.; Lim, C. H.; Lee, J. G.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    The microstructure and growth characteristics of Zircaloy-4 joints brazed by a Zr48Ti16Cu17Ni19 (at.%) amorphous filler metal have been investigated with regard to the controlled isothermal solidification and intermetallic formation. Two typical joints were produced depending on the isothermal brazing temperature: (1) a dendritic growth structure including bulky segregation in the central zone (at 850 °C), and (2) a homogeneous dendritic structure throughout the joint without segregation (at 890 °C). The primary α-Zr phase was solidified isothermally, nucleating to grow into a joint with a cellular or dendritic structure. Also, the continuous Zr2Ni and particulate Zr2Cu phases were formed in the segregated center zone and at the intercellular region, respectively, owing to the different solubility and atomic mobility of the solute elements (Ti, Cu, and Ni) in the α-Zr matrix. A disappearance of the central Zr2Ni phase was also rate-controlled by the outward diffusion of the Cu and Ni elements. When the detrimental Zr2Ni intermetallic phase was eliminated by a complete isothermal solidification at 890 °C, the strengths of the joints were high enough to cause yielding and fracture in the base metal, exceeding those of the bulk Zircaloy-4, at room temperature as well as at elevated temperatures (up to 400 °C).

  15. Charge-Discharge Properties of the Surface-Modified ZrNi Alloy Electrode with Different Degrees of Boiling Alkaline Treatment

    Akihiro Matsuyama

    2016-09-01

    Full Text Available Charge-discharge properties of the surface-modified ZrNi negative electrodes with different degrees of boiling alkaline treatment were investigated. The boiling alkaline treatment was performed by immersing the ZrNi electrode in a boiling 6 M KOH aqueous solution for 2 h or 4 h. The initial discharge capacity for the untreated ZrNi negative electrode was 21 mAh·g−1, but it was increased to 114 mAh·g−1 and 308 mAh·g−1 after the boiling alkaline treatments for 2 h and 4 h, respectively. The discharge capacity for the ZrNi negative electrode after the treatment for 2 h steadily increased with repeating charge-discharge cycles as well as that of the untreated electrode, whereas that for the ZrNi negative electrode after the 4 h treatment greatly decreased. The high rate of dischargeability was improved with an increase in the treatment period of time, and the charge-transfer resistance was drastically decreased. Scanning electron microscopy (SEM and electron dispersive X-ray spectroscopy demonstrated the ZrO2 passive layer on the ZrNi alloy surface was removed by the boiling alkaline treatment to form a porous morphology containing Ni(OH2, which can be reduced to Ni during charging, leading to the reduction of a barrier for the charge-discharge reactions.

  16. Cobalt doped ZrO2 decorated multiwalled carbon nanotube: A promising nanocatalyst for photodegradation of indigo carmine and eosin Y dyes

    William Wilson Anku

    2016-08-01

    Full Text Available This paper reports the degradation of indigo carmine and eosin Y dyes in water, catalyzed by cobalt and multiwalled carbon nanotube modified zirconium oxide nanocomposite (Co-ZrO2-MWCNTs under simulated visible light. The bare ZrO2, ZrO2-MWCNTs, Co-ZrO2 and Co-ZrO2-MWCNTs with different percentage compositions of cobalt were synthesized by homogeneous co-precipitation method. Characterization of the prepared nanocomposites was carried out using X-Ray powder Diffraction (XRD, Fourier Transformer Infrared (FTIR Spectroscopy, Transmission Electron Microscopy (TEM, Raman Spectroscopy, (UV–Vis-Spectroscopy and Energy Dispersive Spectroscopy (EDS for their structure, formation, morphology, size and elemental analysis. The experimental results indicated that all the cobalt and MWCNTs modified nanocomposites demonstrated higher photocatalytic activities compared to the bare ZrO2. The most efficient catalyst (0.5% Co-ZrO2-MWCNTs with the band gap and Ka values of 5.21 eV and 16.86×10−3 min−1 respectively exhibited 98% degradation efficiency toward indigo carmine and 87% toward eosin Y in 180 min.

  17. Surface analytical investigations of the interaction between the getter material ZrCo and hydrogen and the influence of different contamination gases on the hydrogen storage capacity

    Glasbrenner, H.

    1991-11-01

    In this work the results of surface analytical investigations of the alloy ZrCo used for hydrogen storage as well as of the interaction of the alloy with hydrogen and various contamination gases present in a nuclear fusion reactor will be presented and discussed with respect to the application of ZrCo as getter material for tritium. The characterization of the ZrCo alloy showed that on the surface a stable ZrO 2 -layer is formed, which is, however, inhomogeneous. On the phase boundary solid / gas of samples exposed to hydrogen up to the stoichiometrical composition ZrCoH 2.8 a Co enrichment was observed. If the alloy ZrCo is activated before hydrogen take-up in the same way as other getter materials by heating under vacuum, the hydrogenation occurs faster and nearly complete. Zirconium is the alloy component responsible for the hydrogen storage. If a gas reacts nearly exclusively with the alloy component Co, a smaller decrease in the hydrogen storage capacity will be noticed. By exposition to CO and CO 2 mainly compounds with cobalt are formed. However, if the gas produces compounds with Zr like carbide, nitride, or oxide, the result is a strong decrease of the hydrogen storage capacity of the getter. (orig./MM) [de

  18. Comparative study on cubic and tetragonal CexZr1-xO2 supported MoO3-catalysts for sulfur-resistant methanation

    Liu, Zhaopeng; Xu, Yan; Cheng, Jiaming; Wang, Weihan; Wang, Baowei; Li, Zhenhua; Ma, Xinbin

    2018-03-01

    In this paper, two kinds of CexZr1-xO2 solid solution carriers with different Ce/Zr ratio were prepared by one-step co-precipitation method: the cubic Ce0.8Zr0.2O2 and the tetragonal Ce0.2Zr0.8O2 support. The MoO3/Ce0.8Zr0.2O2 and MoO3/Ce0.2Zr0.8O2 catalysts were prepared by incipient wetness impregnation method for comparative study on sulfur-resistant methanation reaction. The N2 adsorption/desorption, X-ray diffraction (XRD), Raman spectroscopy (RS), X-ray photoelectron (XPS), transmission electron microscopy (TEM), temperature-programmed reduction by hydrogen (H2-TPR) were undertaken to characterize the physico-chemical properties of the samples. The results indicated that the prepared MoO3/CexZr1-xO2 catalysts have a mesoporous structure with high surface area and uniform pore size distribution, achieving good MoO3 dispersion on CexZr1-xO2 supports. As for the catalytic performance of sulfur-resistant methanation, the cubic MoO3/Ce0.8Zr0.2O2 exhibited better than the tetragonal MoO3/Ce0.2Zr0.8O2 catalyst at reaction temperature 400 °C and 450 °C. CO conversion on the cubic MoO3/Ce0.8Zr0.2O2 catalyst was 50.1% at 400 °C and 75.5% at 450 °C, which is respectively 7% and 20% higher than that on the tetragonal MoO3/Ce0.2Zr0.8O2 catalyst. These were mainly attributed to higher content of active MoS2 on the surface of catalyst, the enhanced oxygen mobility, increased Mo-species dispersion as well as the excellent reducibility resulted from the increased amount of the reducible Ce3+ on the cubic MoO3/Ce0.8Zr0.2O2 catalyst.

  19. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

    Ohishi, Yuji, E-mail: ohishi@see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Kondo, Toshiki [Graduate School of Engineering, Osaka University (Japan); Ishikawa, Takehiko [Japan Aerospace Exploration Agency (Japan); SOKEN-DAI (Graduate University for Advanced Studies) (Japan); Okada, Junpei T. [Institute for Materials Research, Tohoku University (Japan); Watanabe, Yuki [Advanced Engineering Services Co. Ltd. (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

    2017-03-15

    It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 0.77}Cr{sub 0.23}) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 77}Cr{sub 23}. • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

  20. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

    Ohishi, Yuji; Kondo, Toshiki; Ishikawa, Takehiko; Okada, Junpei T.; Watanabe, Yuki; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-01-01

    It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 0.77 Cr 0.23 ) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 77 Cr 23 . • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

  1. PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKAN MIXER SETTLER

    Dwi Biyantoro

    2017-01-01

    Full Text Available ABSTRAK PEMISAHAN Zr – Hf SECARA SINAMBUNG MENGGUNAKANMIXER SETTLER. Telah dilakukan pemisahanZr – Hf secara sinambung menggunakan pengaduk pengenap (mixer settler 16 stage. Larutan umpan adalah zirkon nitrat dengan kadar Zr = 30786 ppm dan Hf = 499 ppm. Ekstraktan dipakai adalah solven 60 % TBP dalam kerosen dan larutan scrubbingyang dipakai adalah asam nitrat 1 M. Umpan masuk pada stageke 5 dikontakkan secara berlawanan arah dengan solven masuk pada stage ke 16 dan larutan scrubbing masuk pada stage ke 1. Tujuan penelitian ini adalah memisahkan unsur Zr dan Hf dari hasil olah pasir zirkon menggunakan solven TBP dengan alat mixer settler16 stage. Analisis umpan dan hasil proses pemisahan untuk zirkonium (Zr dilakukan dengan menggunakan alat pendar sinar-X, sedangkananalisis unsur hafnium (Hf menggunakan Analisis Pengaktifan Neutron (APN. Parameter penelitian dilakukan dengan variasi keasaman asam nitrat dalam umpan dan variasi waktu pada berbagai laju pengadukan. Hasil penelitian pemisahan unsur Zr dengan Hf diperolehkondisi optimum pada keasaman umpan 4 N HNO3, keseimbangan dicapai setelah 3jam dan laju pengadukan 3300 rpm. Hasil ekstrak  unsur zirkon (Zr diperoleh kadar sebesar 28577 ppm dengan efisiensi 92,76 % serta kadar pengotor hafnium (Hf sebesar 95 ppm. Kata Kunci: pemisahan Zr, Hf, ekstraksi, mixer settler, alat pendar sinar-X, APN. ABSTRACT SEPARATION of Zr - Hf CONTINUOUSLY USE THE MIXER SETTLER. Separation of Zr - Hf continuously using mixer settler 16 stage has been done. The feed solution is zircon nitrate concentration of Zr = 30786 ppm  and Hf = 499 ppm. As the solvent used extractant 60 % TBP in 40 % kerosene. Nitric acid solution used srubbing 1 M. The feed entered into stage to 5 is contacted with solvents direction on the stage to 16 and the scrubbing solution enter the stage to 1. The purpose of this study is to separate Zr and Hf of the results from the process of zircon sand using solvent TBP using 16 stage

  2. Improved conversion efficiency of dye sensitized solar cell using Zn doped TiO{sub 2}-ZrO{sub 2} nanocomposite

    Tomar, Laxmi J., E-mail: laxmi-tomar86@yahoo.com; Bhatt, Piyush J.; Desai, Rahul K.; Chakrabarty, B. S.; Panchal, C. J. [Department of Applied Physics, Faculty of Technology and Engineering, The M. S. University of Baroda, Vadodara, India-390003 (India)

    2016-05-23

    TiO{sub 2}-ZrO{sub 2} and Zn doped TiO{sub 2}-ZrO{sub 2} nanocomposites were prepared by hydrothermal method for dye sensitized solar cell (DSSC) application. The structural and optical properties were investigated by X –ray diffraction (XRD) and UV-Visible spectroscopy respectively. XRD results revealed the formation of material in nano size. The average crystallite size is 22.32 nm, 17.41 nm and 6.31 nm for TiO{sub 2}, TiO{sub 2}-ZrO{sub 2} and Zn doped TiO{sub 2}-ZrO{sub 2} nanocomposites respectively. The optical bandgap varies from 2.04 eV to 3.75 eV. Dye sensitized solar cells were fabricated using the prepared material. Pomegranate juice was used as a sensitizer and graphite coated conducting glass plate was used as counter electrode. The I – V characteristics were recorded to measure photo response of DSSC. Photovoltaic parameter like open circuit voltage, power conversion efficiency, and fill factor were evaluated for fabricated solar cell. The power conversion efficiency of DSSC fabricated with TiO{sub 2}, TiO{sub 2}-ZrO{sub 2} and Zn doped TiO{sub 2}-ZrO{sub 2} nanocomposites were found 0.71%, 1.97% and 4.58% respectively.

  3. Thermodynamic study of CVD-ZrO2 phase diagrams

    Torres-Huerta, A.M.; Vargas-Garcia, J.R.; Dominguez-Crespo, M.A.; Romero-Serrano, J.A.

    2009-01-01

    Chemical vapor deposition (CVD) of zirconium oxide (ZrO 2 ) from zirconium acetylacetonate Zr(acac) 4 has been thermodynamically investigated using the Gibbs' free energy minimization method and the FACTSAGE program. Thermodynamic data Cp o , ΔH o and S o for Zr(acac) 4 have been estimated using the Meghreblian-Crawford-Parr and Benson methods because they are not available in the literature. The effect of deposition parameters, such as temperature and pressure, on the extension of the region where pure ZrO 2 can be deposited was analyzed. The results are presented as calculated CVD stability diagrams. The phase diagrams showed two zones, one of them corresponds to pure monoclinic phase of ZrO 2 and the other one corresponds to a mix of monoclinic phase of ZrO 2 and graphite carbon.

  4. Development of AMS procedure for measurement of 93Zr

    Lu, Wenting; Collon, Philippe; Kashiv, Yoav; Bowers, Matthew; Robertson, Daniel; Schmitt, Christopher

    2011-10-01

    The procedure for measuring 93Zr (t1/2 = 1.5 Ma) by AMS is currently being developed at the Nuclear Science Lab at the University of Notre Dame and we report on first experiments performed in this direction. AMS detection of 93Zr can potentially be applied to address astrophysical and environmental issues: (1) the measurement of the 92Zr(n,γ)93Zr reaction cross-section at nucleosynthesis s-process relevant temperatures, (2) the search for potential live 93Zr from a supernova in deep sea sediments, (3) hydrological and radioactive waste tracing. The measurement of 93Zr requires adequate separation from its stable isobar 93Nb. We are currently working on optimizing this separation by using the GasFilled Magnet technique with additional multiple dE measurements in a focal plane ionization chamber.

  5. Diffusion studies in amorphous NiZr alloys

    Hahn, H.; Averback, R.S.; Hoshino, K.; Rothman, S.J.

    1987-06-01

    Tracer impurity and self diffusion measurements have been made on amorphous (a-) NiZr alloys using radioactive tracer, Secondary Ion Mass Spectrometry and Rutherford backscattering techniques. The temperature dependence of diffusion in a-NiZr can be represented in the form D = D 0 exp(-Q/kT), with no structural relaxation effects being observed. The mobility of an atom in a-NiZr increased dramatically with decreasing atomic radius of the diffusing atom and also with decreasing Ni content for Ni concentrations below ≅40 at. %. These diffusion characteristics in a-NiZr are remarkably similar to those in α-Zr and α-Ti. These mechanisms assume that Zr and Ti provide a close packed structure, either crystalline or amorphous, through which small atoms diffuse by an interstitial mechanism and large atoms diffuse by a vacancy mechanism. 12 refs., 2 figs., 2 tabs

  6. Effects of molybdenum content on the structure and mechanical properties of as-cast Ti-10Zr-based alloys for biomedical applications

    Ho, Wen-Fu, E-mail: fujiiwfho@yahoo.com.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua, Taiwan (China); Wu, Shih-Ching; Hsu, Shih-Kuang [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Li, Yu-Chi [Department of Materials Science and Engineering, Da-Yeh University, Changhua, Taiwan (China); Hsu, Hsueh-Chuan, E-mail: hchsu@ctust.edu.tw [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taiwan (China)

    2012-04-01

    The effects of molybdenum on the structure and mechanical properties of a Ti-10Zr-based system were studied with an emphasis on improving the strength/modulus ratio. Commercially pure titanium (c.p. Ti) was used as a control. As-cast Ti-10Zr and a series of Ti-10Zr-xMo (x = 1, 3, 5, 7.5, 10, 12.5, 15, 17.5 and 20 wt.%) alloys prepared using a commercial arc-melting vacuum pressure casting system were investigated. X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The experimental results indicated that these alloys had different structures and mechanical properties when various amounts of Mo were added. The as-cast Ti-10Zr has a hexagonal {alpha} Prime phase, and when 1 wt.% Mo was introduced into the Ti-10Zr alloy, the structure remained essentially unchanged. However, with 3 or 5 wt.%, the martensitic {alpha} Double-Prime structure was found. When increased to 7.5 wt.% or greater, retention of the metastable {beta} phase began. The {omega} phase was observed only in the Ti-10Zr-7.5Mo alloy. Among all Ti-10Zr-xMo alloys, the {alpha} Double-Prime -phase Ti-10Zr-5Mo alloy had the lowest elastic modulus. It is noteworthy that all the Ti-10Zr and Ti-10Zr-xMo alloys had good ductility. In addition, the Ti-10Zr-5Mo and Ti-10Zr-12.5Mo alloys exhibited higher bending strength/modulus ratios at 20.1 and 20.4, respectively. Furthermore, the elastically recoverable angles of these two alloys (26.4 Degree-Sign and 24.6 Degree-Sign , respectively) were much greater than those of c.p. Ti (2.7 Degree-Sign ). Given the importance of these properties for implant materials, the low modulus, excellent elastic recovery capability and high strength/modulus ratio of {alpha} Double-Prime phase Ti-10Zr-5Mo and {beta} phase Ti-10Zr-12.5Mo alloys appear to make them promising candidates. - Highlights: Black-Right-Pointing-Pointer The effects of Mo on the structure

  7. Mössbauer spectroscopic studies in U-Fe and U-Fe-Zr alloys

    Panda, Alaka; Singh, L. Herojit; Rajagopalan, S.; Govindaraj, R., E-mail: govind@igcar.gov.in; Ramachandran, Renjith; Kalavathi, S.; Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2016-05-23

    {sup 57}Fe Mössbauer studies have been carried out in an alloy of U and Fe with atomic percentage in the ratio of 68%:32% in order to understand the local structure and valence of Fe atoms associated with different phases that may get formed. The effect of changes in the hyperfine parameters such as isomer shift and quadrupole splitting at Fe sites due to additional alloying of Zr has been studied in an alloy of U, Fe and Zr in the ratio of 44%:33%:23% respectively with respect to that of the U-Fe alloy chosen in the present study. Possible effect of solute clustering in these systems has been addressed in an analogous alloy of uranium and zirconium using positron lifetime spectroscopy.

  8. Effect of photocatalytic reduction of carbon dioxide by N-Zr co-doped nano TiO2.

    Zhang, Ru; Wang, Li; Kang, Zhuo; Li, Qiang; Pan, Huixian

    2017-11-01

    Modified sol-gel method was adopted to prepare TiO 2 , Zr-TiO 2 and N/Zr-TiO 2 composite catalyst. The as-synthesized photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunner- Emmet- Teller measurement and UV-Vis diffuse reflectance spectroscopy. And the photocatalytic performance toward CO 2 reduction was evaluated under ultraviolet light. The catalyst particles were demonstrated in the nanometer level size. When N and Zr are co-doped, on the one hand, Ti 4+ can be replaced by Zr 4  +, which leads to lattice distortion and inhibits electron-hole recombination. On the other hand, N enters into TiO 2 lattice gap to form O-Ti-N bond structure, and partial Ti 4+ are reduced to Ti 3+ . Compared with pristine TiO 2 , the specific surface area and the band gap of N/Zr-TiO 2 were improved and reduced, respectively. The N and Zr synergistically contribute to the obviously strengthened absorption intensity in visible region, as well as significantly improved photocatalytic activity. In the gas phase reactor, when the calcination temperature was 550°C, 0.125N/0.25Zr-TiO 2 composite performed the highest photocatalytic activity UV irradiation for 8 h, and the corresponding CH 4 yield was 11.837 µmol/g, which was 87.8% higher than that of pristine TiO 2 . For the visible light, the CH 4 yield was 9.003 µmol/g after 8 h irradiation, which was 83.9% higher than that of pristine TiO 2 .

  9. Aqueous corrosion study on U-Zr alloy

    Pal, Titas; Venkatesan, V.; Kumar, Pradeep; Khan, K.B.; Kumar, Arun

    2009-01-01

    In low power or research reactor, U-Zr alloy is a potential candidate for dispersion fuel. Moreover, Zirconium has a low thermal-neutron cross section and uranium alloyed with Zr has excellent corrosion resistance and dimensional stability during thermal cycling. In the present study aqueous corrosion behavior of U-Zr alloy samples was studied in autoclave at 200 deg C temperature. Corrosion rate was determined from weight loss with time. (author)

  10. Effects of interfacial layer on characteristics of TiN/ZrO2 structures.

    Kim, Younsoo; Kang, Sang Yeol; Choi, Jae Hyoung; Lim, Jae Soon; Park, Min Young; Chung, Suk-Jin; Chung, Jaegwan; Lee, Hyung Ik; Kim, Ki Hong; Kyoung, Yong Koo; Heo, Sung; Yoo, Cha Young; Kang, Ho-Kyu

    2011-09-01

    To minimize the formation of unwanted interfacial layers, thin interfacial layer (ZrCN layer) was deposited between TiN bottom electrode and ZrO2 dielectric in TiN/ZrO2/TiN capacitor. Carbon and nitrogen were also involved in the layer because ZrCN layer was thermally deposited using TEMAZ without any reactant. Electrical characteristics of TiN/ZrO2/TiN capacitor were improved by insertion of ZrCN layer. The oxidation of TiN bottom electrode was largely inhibited at TiN/ZrCN/ZrO2 structure compared to TiN/ZrO2 structure. While the sheet resistance of TiN/ZrCN/ZrO2 structure was constantly sustained with increasing ZrO2 thickness, the large increase of sheet resistance was observed in TiN/ZrO2 structure after 6 nm ZrO2 deposition. When ZrO2 films were deposited on ZrCN layer, the deposition rate of ZrO2 also increased. It is believed that ZrCN layer acted both as a protection layer of TiN oxidation and a seed layer of ZrO2 growth.

  11. Steam oxidation of Zr 1% Nb clads of VVER fuels in high temperature

    Solyanyj, V.I.; Bibilashvili, Yu.K.; Dranenko, V.V.; Levin, A.Ya.; Izrajlevskij, L.B.; Morozov, A.M.

    1984-01-01

    In a wide range of accident conditions processes of clad corrosion effected by steam are rather intensive and in many respects influence the safety of NPP and the after-accident dismantling of a reactor core. This paper discusses the results of comprehensive studies into corrosion behaviour of Zr 1%Nb clads of VVER-type fuels at high temperatures. These studies are a continuation of previous work and the base for the design modelling of corrosion processes

  12. Effects of Sc and Zr on mechanical property and microstructure of tungsten inert gas and friction stir welded aerospace high strength Al–Zn–Mg alloys

    Deng, Ying, E-mail: csudengying@163.com [School of Metallurgy and Environment, Central South University, Hunan, Changsha 410083 (China); School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China); State Key Laboratory for Power Metallurgy, Central South University, Hunan, Changsha 410083 (China); Peng, Bing [School of Metallurgy and Environment, Central South University, Hunan, Changsha 410083 (China); Xu, Guofu, E-mail: csuxgf66@csu.edu.cn [School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China); State Key Laboratory for Power Metallurgy, Central South University, Hunan, Changsha 410083 (China); Pan, Qinglin; Yin, Zhimin; Ye, Rui [School of Materials Science and Engineering, Central South University, Hunan, Changsha 410083 (China); Wang, Yingjun; Lu, Liying [Northeast Light Alloy Co. Ltd., Hei Longjiang, Harbin 150060 (China)

    2015-07-15

    New aerospace high strength Al–Zn–Mg and Al–Zn–Mg–0.25Sc–0.10Zr (wt%) alloys were welded by tungsten inert gas (TIG) process using a new Al–6.0Mg–0.25Sc–0.10Zr (wt%) filler material, and friction stir welding (FSW) process, respectively. Mechanical property and microstructure of the welded joints were investigated comparatively by tensile tests and microscopy methods. The results show that Sc and Zr can improve the yield strength and ultimate tensile strength of Al–Zn–Mg alloy by 59 MPa (23.3%) and 16 MPa (4.0%) in TIG welded joints, and by 77 MPa (23.8%) and 54 MPa (11.9%) in FSW welded joints, respectively. The ultimate tensile strength and elongation of new Al–Zn–Mg–Sc–Zr alloy FSW welded joint are 506±4 MPa and 6.34±0.2%, respectively, showing superior post welded performance. Mechanical property of welded joint is mainly controlled by its “weakest microstructural zone”. TIG welded Al–Zn–Mg and Al–Zn–Mg–Sc–Zr alloys reinforced with weld bead both failed at fusion boundaries. Secondary Al{sub 3}Sc{sub x}Zr{sub 1−x} particles originally present in parent alloy coarsen during TIG welding process, but they can restrain the grain growth and recrystallization here, thus improving welding performance. For two FSW welded joints, fracture occurred in weld nugget zone. Secondary Al{sub 3}Sc{sub x}Zr{sub 1−x} nano-particles almost can keep unchangeable size (20–40 nm) across the entire FSW welded joint, and thus provide effective Orowan strengthening, grain boundary strengthening and substructure strengthening to strengthen FSW joints. The positive effect from Sc and Zr additions into base metals can be better preserved by FSW process than by TIG welding process.

  13. Effects of Sc and Zr on mechanical property and microstructure of tungsten inert gas and friction stir welded aerospace high strength Al–Zn–Mg alloys

    Deng, Ying; Peng, Bing; Xu, Guofu; Pan, Qinglin; Yin, Zhimin; Ye, Rui; Wang, Yingjun; Lu, Liying

    2015-01-01

    New aerospace high strength Al–Zn–Mg and Al–Zn–Mg–0.25Sc–0.10Zr (wt%) alloys were welded by tungsten inert gas (TIG) process using a new Al–6.0Mg–0.25Sc–0.10Zr (wt%) filler material, and friction stir welding (FSW) process, respectively. Mechanical property and microstructure of the welded joints were investigated comparatively by tensile tests and microscopy methods. The results show that Sc and Zr can improve the yield strength and ultimate tensile strength of Al–Zn–Mg alloy by 59 MPa (23.3%) and 16 MPa (4.0%) in TIG welded joints, and by 77 MPa (23.8%) and 54 MPa (11.9%) in FSW welded joints, respectively. The ultimate tensile strength and elongation of new Al–Zn–Mg–Sc–Zr alloy FSW welded joint are 506±4 MPa and 6.34±0.2%, respectively, showing superior post welded performance. Mechanical property of welded joint is mainly controlled by its “weakest microstructural zone”. TIG welded Al–Zn–Mg and Al–Zn–Mg–Sc–Zr alloys reinforced with weld bead both failed at fusion boundaries. Secondary Al 3 Sc x Zr 1−x particles originally present in parent alloy coarsen during TIG welding process, but they can restrain the grain growth and recrystallization here, thus improving welding performance. For two FSW welded joints, fracture occurred in weld nugget zone. Secondary Al 3 Sc x Zr 1−x nano-particles almost can keep unchangeable size (20–40 nm) across the entire FSW welded joint, and thus provide effective Orowan strengthening, grain boundary strengthening and substructure strengthening to strengthen FSW joints. The positive effect from Sc and Zr additions into base metals can be better preserved by FSW process than by TIG welding process

  14. Ultra-thin zirconia films on Zr-alloys

    Choi, Joong Il Jake; Mayr-Schmoelzer, Wernfried; Mittendorfer, Florian; Redinger, Josef; Diebold, Ulrike; Schmid, Michael [Institute of Applied Physics, Vienna University of Technology (Austria); Li, Hao; Rupprechter, Guenther [Institute of Materials Chemistry, Vienna University of Technology (Austria)

    2014-07-01

    Zirconia ultra-thin films have been prepared by oxidation of Pt{sub 3}Zr(0001) and showed a structure equivalent to (111) of cubic zirconia. Following previous work, we have prepared ultra-thin zirconia by oxidation of a different alloy, Pd{sub 3}Zr(0001), which resulted in a similar structure with a slightly different lattice parameter, 351.2 ±0.4 pm. Unlike the oxide on Pt{sub 3}Zr, where Zr of the oxide binds to Pt in the substrate, here the oxide binds to substrate Zr via oxygen. This causes stronger distortion of the oxide structure, i.e. a stronger buckling of Zr in the oxide. After additional oxidation of ZrO{sub 2}/Pt{sub 3}Zr, a different ultra-thin zirconia phase is observed. A preliminary structure model for this film is based on (113)-oriented cubic zirconia. 3D oxide clusters are also present after growing ultra-thin zirconia films. They occur at the step edges, and the density is higher on Pd{sub 3}Zr. These clusters also appear on terraces after additional oxidation. XPS reveals different core level shifts of the oxide films, bulk, and oxide clusters.

  15. Pumping of methane by an ionization assisted Zr/Al getter pump

    Shen, G.L.

    1987-01-01

    The pumping of methane by an ionization assisted Zr/Al getter pump has been investigated. This pump consists of 12 pieces of ring getters. A spiral shape W filament is located within the ring getters. A bias voltage is applied across the filament and the getter itself. The experiments have shown that (1) when the bias voltage is turned off, the pumping speed of the getter pump for methane increases exponentially with the filament temperature; (2) when the filament temperature is held constant, its pumping speed varies directly with the ionization electron current; (3) when the filament temperature is 2063 0 C and the electron current is 57 mA, the pumping speed of the Zr/Al getter pump is 475 ml/s, and the specific speed is 16.8 ml/s cm 2 ; and (4) an activation energy and critical temperature measured for methane molecules decomposition are, respectively, 47.4 kcal/mol and about 1700 0 C. Analysis of the results indicates that methane is pumped by an ionization assisted Zr/Al getter pump not because of the adsorption and the diffusion of methane molecules directly, but because methane molecules are decomposed as C and H 2 through a catalysis of the hot W filament, carbon is adsorbed on the surface of the W filament, and is diffused into the interior of the W lattice. H 2 is immediately absorbed by the Zr/Al getters. Besides, electron impact with CH 4 would result in the additional decomposition and ionization, then the effect of electron bombardment enhances methane pumping by the Zr/Al getters

  16. Hydrogenation of FeCoZr-Al{sub 2}O{sub 3} nanocomposites studied by Moessbauer spectroscopy and magnetometry

    Saad, A. [Al-Balqa Applied University, Appl. Science Department (Jordan); Kasiuk, J.; Fedotova, J., E-mail: Julia@hep.by [NC PHEP BSU (Belarus); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics (Hungary); Przewoznik, J.; Kapusta, Cz. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science (Poland); Marszalek, M. [Niewodniczanski Institute of Nuclear Physics PAN (Poland)

    2009-02-15

    Hydrogenation effects on crystalline and magnetic structure of nanocomposites (FeCoZr){sub x}(Al{sub 2}O{sub 3}){sub 100-x}, 38 {<=} x {<=} 63 at.% are studied by {sup 57}Fe Moessbauer spectroscopy and magnetometry. Variations of local structure, blocking temperature and mean FeCoZr nanoparticles' volume are discussed with respect to (i) composition and (ii) two competing processes-H{sub 2} incorporation and annealing-occurred during treatment in H{sub 2} plasma.

  17. Investigation of electronic, magnetic and thermoelectric properties of Zr{sub 2}NiZ (Z = Al,Ga) ferromagnets

    Yousuf, Saleem, E-mail: nengroosaleem17@gmail.com; Gupta, Dinesh C., E-mail: sosfizix@gmail.com

    2017-05-01

    Systematic investigation of impact of electronic structure and magnetism, on the thermoelectric properties of new Zr{sub 2}NiZ (Z = Al, Ga) Heusler alloys are determined using density functional theory calculations. Half-metallicity with ferromagnetic character is supported by their 100% spin polarizations at the Fermi level. Magnetic moment of ∼3 μ{sub B} is according to the Slater-Puling rule, enables their practical applications. Electron density plots are used to analyse the nature of bonding and chemical composition. Boltzmann's theory is conveniently employed to investigate the thermoelectric properties of these compounds. The analysis of the thermal transport properties specifies the Seebeck coefficient as 25.6 μV/K and 18.6 μV/K at room temperature for Zr{sub 2}NiAl and Zr{sub 2}NiGa, respectively. The half-metallic nature with efficient thermoelectric coefficients suggests the likelihood of these materials to have application in designing spintronic devices and imminent thermoelectric materials. - Highlights: • The compounds are half-metallic ferromagnets. • 100% spin-polarized compounds for spintronics. • Increasing Seebeck coefficient over a wide temperature range. • Zr{sub 2}NiAl is efficient thermoelectric material than Zr{sub 2}NiGa.

  18. Enhanced dielectric properties of ZrO2 thin films prepared in nitrogen ambient by pulsed laser deposition

    Zhu, J; Li, T L; Pan, B; Zhou, L; Liu, Z G

    2003-01-01

    ZrO 2 thin films were fabricated in O 2 ambient and in N 2 ambient by pulsed laser deposition (PLD), respectively. X-ray diffraction revealed that films prepared at 400 deg. C remained amorphous. The dielectric properties of amorphous ZrO 2 films were investigated by measuring the capacitance-frequency characteristics of Pt/ZrO 2 /Pt capacitor structures. The dielectric constant of the films deposited in N 2 ambient was larger than that of the films deposited in O 2 ambient. The dielectric loss was lower for films prepared in N 2 ambient. Atom force microscopy investigation indicated that films deposited in N 2 ambient had smoother surface than films deposited in O 2 ambient. Capacitance-voltage and current-voltage characteristics were studied. The equivalent oxide thickness (EOT) of films with 6.6 nm physical thickness deposited in N 2 ambient is lower than that of films deposited in O 2 ambient. An EOT of 1.38 nm for the film deposited in N 2 ambient was obtained, while the leakage current density was 94.6 mA cm -2 . Therefore, ZrO 2 thins deposited in N 2 ambient have enhanced dielectric properties due to the incorporation of nitrogen which leads to the formation of Zr-doped nitride interfacial layer, and is suggested to be a potential material for alternative high-k (high dielectric constant) gate dielectric applications

  19. The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

    Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

    2016-10-01

    An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO2, ZrO2, V2O5, Al2O3, etc.), metal fluoride (ZrF4, AlF3, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

  20. Simulation of Zr content in TiZrCuNi brazing filler metal for Ti6Al4V alloy

    Yue, Xishan; Xie, Zonghong; Jing, Yongjuan

    2017-01-01

    To optimize the Zr content in Ti-based filler metal, the covalent electron on the nearest atoms bond in unit cell (n_A"u"-"v) with Ti-based BCC structure was calculated, in which the brazing temperature was considered due to its influence on the lattice parameter. Based on EET theory (The Empirical Electron Theory for solid and molecules), n_A"u"-"v represents the strength of the unit cell with defined element composition and structure, which reflects the effect from solid solution strengthening on the strength of the unit cell. For Ti-Zr-15Cu-10Ni wt% filler metal, it kept constant as 0.3476 with Zr as 37.5 ∝ 45 wt% and decreased to 0.333 with Zr decreasing from 37.5 to 25 wt%. Finally, it increased up to 0.3406 with Zr as 2 ∝ 10 wt%. Thus, Ti-based filler metal with Zr content being 2 ∝ 10 wt% is suggested based on the simulation results. Moreover, the calculated covalent electron of n_A"u"-"v showed good agreement with the hardness of the joint by filler 37.5Zr and 10Zr. The composition of Ti-10Zr-15Cu-10Ni wt% was verified in this study with higher tensile strength of the brazing joint and uniform microstructure of the interface. (orig.)

  1. Simulation of Zr content in TiZrCuNi brazing filler metal for Ti6Al4V alloy

    Yue, Xishan [Northwestern Polytechnical University, School of Astronautics, Xi' an (China); AVIC Beijing Aeronautical Manufacturing Technology Research Institute, Aeronautical Key Laboratory for Welding and Joining Technology, Beijing (China); Xie, Zonghong [Northwestern Polytechnical University, School of Astronautics, Xi' an (China); Jing, Yongjuan [AVIC Beijing Aeronautical Manufacturing Technology Research Institute, Aeronautical Key Laboratory for Welding and Joining Technology, Beijing (China)

    2017-07-15

    To optimize the Zr content in Ti-based filler metal, the covalent electron on the nearest atoms bond in unit cell (n{sub A}{sup u-v}) with Ti-based BCC structure was calculated, in which the brazing temperature was considered due to its influence on the lattice parameter. Based on EET theory (The Empirical Electron Theory for solid and molecules), n{sub A}{sup u-v} represents the strength of the unit cell with defined element composition and structure, which reflects the effect from solid solution strengthening on the strength of the unit cell. For Ti-Zr-15Cu-10Ni wt% filler metal, it kept constant as 0.3476 with Zr as 37.5 ∝ 45 wt% and decreased to 0.333 with Zr decreasing from 37.5 to 25 wt%. Finally, it increased up to 0.3406 with Zr as 2 ∝ 10 wt%. Thus, Ti-based filler metal with Zr content being 2 ∝ 10 wt% is suggested based on the simulation results. Moreover, the calculated covalent electron of n{sub A}{sup u-v} showed good agreement with the hardness of the joint by filler 37.5Zr and 10Zr. The composition of Ti-10Zr-15Cu-10Ni wt% was verified in this study with higher tensile strength of the brazing joint and uniform microstructure of the interface. (orig.)

  2. NIR to visible frequency upconversion in Er{sup 3+} and Yb{sup 3+} codoped ZrO{sub 2} phosphor

    Singh, Vijay; Kim, Sang Hwan [Konkuk University, Department of Chemical Engineering, Seoul (Korea, Republic of); Rai, Vineet Kumar [Indian School of Mines, Department of Applied Physics, Dhanbad (India); Al-Shamery, Katharina [University of Oldenburg, Physical Chemistry, Institute for Pure and Applied Chemistry and Center of Interface Science, Oldenburg (Germany); Haase, Markus [University of Osnabrueck, Department of Inorganic Chemistry I-Materials Research, Institute of Chemistry, Osnabrueck (Germany)

    2013-11-15

    The ZrO{sub 2}:Er{sup 3+} codoped with Yb{sup 3+} phosphor powders have been prepared by the urea combustion route. Formation of the compounds ZrO{sub 2}:Er{sup 3+} and ZrO{sub 2}:Er{sup 3+}, Yb{sup 3+} was confirmed by XRD. The frequency upconversion emissions in the green and red regions upon excitation with a CW diode laser at {proportional_to}978 nm are reported. Codoping with Yb{sup 3+} enhances the emission intensities of the triply ionized erbium in the green and red spectral regions by about {proportional_to}130 and {proportional_to}820 times respectively. The emission properties of the ZrO{sub 2}:Er{sup 3+} phosphor powders are discussed on the basis of excited state absorption, energy transfer, and cross-relaxation energy transfer mechanisms. (orig.)

  3. PEALD grown high-k ZrO{sub 2} thin films on SiC group IV compound semiconductor

    Khairnar, A. G., E-mail: agkhairnar@gmail.com; Patil, V. S.; Agrawal, K. S.; Salunke, R. S.; Mahajan, A. M., E-mail: ammahajan@nmu.ac.in [North Maharashtra University, Department of Electronics, School of Physical Sciences (India)

    2017-01-15

    The study of ZrO{sub 2} thin films on SiC group IV compound semiconductor has been studied as a high mobility substrates. The ZrO{sub 2} thin films were deposited using the Plasma Enhanced Atomic Layer Deposition System. The thickness of the thin films were measured using ellipsometer and found to be 5.47 nm. The deposited ZrO{sub 2} thin films were post deposition annealed in rapid thermal annealing chamber at temperature of 400°Ð¡. The atomic force microscopy and X-гау photoelectron spectroscopy has been carried out to study the surface topography, roughness and chemical composition of thin film, respectively.

  4. SEM in situ MiniCantilever Beam Bending of U-10Mo/Zr/Al Fuel Elements

    Mook, William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Baldwin, Jon K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Ricardo M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mara, Nathan A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-06-16

    In this work, the fracture behavior of Al/Zr and Zr/dU-10Mo interfaces was measured via the minicantilever bend technique. The energy dissipation rates were found to be approximately 3.7-5 mj/mm2 and 5.9 mj/mm2 for each interface, respectively. It was found that in order to test the Zr/U-10Mo interface, location of the hinge of the cantilever was a key parameter. While this test could be adapted to hot cell use through careful alignment fixturing and measurement of crack lengths with an optical microscope (as opposed to SEM, which was used here out of convenience), machining of the cantilevers via MiniMill in such a way as to locate the interfaces at the cantilever hinge, as well as proper placement of a femtosecond laser notch will continue to be key challenges in a hot cell environment.

  5. Influence of Zr doping on structure and morphology of TiO2 nanorods prepared using hydrothermal method

    Muslimin, Masliana; Jumali, Mohammad Hafizuddin; Tee, Tan Sin; Beng, Lee Hock; Hui, Tan Chun; Chin, Yap Chi

    2018-04-01

    The aim of this work is to investigate the effect of Zr doping on TiO2 nanostructure. TiO2 nanorods thin films with different Zr-doping concentrations (6 × 10-3 M, 13 × 10-3 M and 25 × 10-3 M) were successfully prepared using a simple hydrothermal method. The structural and morphological properties of the samples were evaluated using XRD and FESEM respectively. The XRD results revealed that the TiO2 in all samples stabilized as rutile phase. The FESEM micrographs confirmed that TiO2 exist as square like nanorods with blunt tips. Although the crystallographic nature remains unchanged, the introduction of Zr has altered the surface density, structure and morphology of TiO2 which subsequently will have significant effect on its properties.

  6. Growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallites in 3 mol% yttria partially stabilized ZrO{sub 2} (3Y-PSZ) precursor powder

    Kuo, Chih-Wei [Department of Resources Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Lee, Kuen-Chan [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Yen, Feng-Lin, E-mail: flyen@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Shen, Yun-Hwei [Department of Resources Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Lee, Huey-Er [Department of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University, Chung Ho Memorial Hospital, 100 Tzyou 1st Road, Kaohsiung 807, Taiwan (China); Wen, Shaw-Bing [General Education Center, Meiho Institute of Technology, 23 Pingguang Road, Neipu, Pingtung 91202, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Stack, Margaret Mary [Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow (United Kingdom)

    2014-04-01

    Highlights: • The crystalline structures were composed of tetragonal and monoclinic ZrO{sub 2}. • Growth kinetics of t-ZrO{sub 2} in the 3Y-PSZ precursor powder is described as: D{sub te}{sup 2}=(4.57±0.55)t{sup 0.12±0.02}exp(-((24.79±0.38)×10{sup 3})/(RT) ). • Growth kinetics of m-ZrO{sub 2} in the 3Y-PSZ precursor powder is described as: D{sub m}{sup 2}=(4.40±1.63)t{sup 0.17±0.08}exp(-((66.47±3.97)×10{sup 3})/(RT) ). - Abstract: The growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallites in 3 mol% yttria partially stabilized ZrO{sub 2} (3Y-PSZ) precursor powder has been investigated using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, transmission electron microscopy (TEM) and high resolution TEM (HRTEM). After calcination of the 3Y-PSZ precursor powder between 773 and 1073 K for 2 h, the crystalline structures were composed of tetragonal and monoclinic ZrO{sub 2} as the primary and secondary phases, respectively. When the 3Y-PSZ precursor powder was calcined at 773 K for 2 h, the BET specific surface area was 97.13 m{sup 2}/g, which is equivalent to a particle size of 10.30 nm. The crystallite sizes determined via XRD and BET agreed well, indicating that the powder was virtually non-agglomerated. The growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallite isothermal growth in the 3Y-PSZ precursor powder are described by: D{sub te}{sup 2}=(4.57±0.55)t{sup 0.12±0.02}exp(-((24.79±0.38)×10{sup 3})/(RT) ) and D{sub m}{sup 2}=(4.40±1.63)t{sup 0.17±0.08}exp(-((66.47±3.97)×10{sup 3})/(RT) ), respectively, for 773K≤T≤1073K. D{sub te} and D{sub m} denote the crystallite size of tetragonal and monoclinic ZrO{sub 2} at time t and temperature T, respectively.

  7. Equality, self‐respect and voluntary separation

    Merry, M.S.

    2012-01-01

    This paper argues that self‐respect constitutes an important value, and further, an important basis for equality. It also argues that under conditions of inequality‐producing segregation, voluntary separation in schooling may be more likely to provide the resources necessary for self‐respect. A

  8. A novel vibrotactile system for stimulating the glabrous skin of awake freely behaving rats during operant conditioning.

    Devecioğlu, İsmail; Güçlü, Burak

    2015-03-15

    Rat skin is innervated by mechanoreceptive fibers similar to those in other mammals. Tactile experiments with behaving rats mostly focus on the vibrissal system which does not exist in humans. The aim of this study was to design and implement a novel vibrotactile system to stimulate the glabrous skin of behaving rats during operant conditioning. A computer-controlled vibrotactile system was developed for various tasks in which the volar surface of unrestrained rats' fore- and hindpaws was stimulated in an operant chamber. The operant chamber was built from off-the-shelf components. A highly accurate electrodynamic shaker with a novel multi-probe design was used for generating mechanical displacements. Twenty-five rats were trained for four sequential tasks: (A) middle-lever (trial start signal) press, (B) side-lever press with an associated visual cue, (C) similar to (B) with the addition of an auditory/tactile stimulus, (D) auditory/tactile detection (yes/no) task. Out of 9 rats which could complete the tactile version of this training schedule, 5 had over 70% accuracy in the tactile version of the detection task. Unlike actuators for stimulating whiskers, this system does not require a particular head/body alignment and can be used with freely behaving animals. The vibrotactile system was found to be effective for conditioning freely behaving rats based on stimuli applied on the glabrous skin. However, detection accuracies were lower compared to those in tasks involving whisker stimulation reported previously, probably due to differences in cortical processing. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Calorimetric studies on ZrC(s)

    Banerjee, Aparna; Venugopal, V.

    1998-01-01

    Enthalpy increments of ZrC(s) were determined using a Calvet micro-calorimeter in the temperature range 349.5 to 664.0 K. The enthalpy increment values were least squares analysed using the SHOMATE programme and the best fit is represented by the following polynomial equation: H o (T)-H o (298.15 K)(J/mol) = 48.44 T(K) + 0.375x10 -2 T 2 (K) + 11.67x10 5 /T(K) - 18691.97. Molar heat capacity and other thermal properties have been evaluated. (author)

  10. Neutron capture cross section of $^{93}$Zr

    We propose to measure the neutron capture cross section of the radioactive isotope $^{93}$Zr. This project aims at the substantial improvement of existing results for applications in nuclear astrophysics and emerging nuclear technologies. In particular, the superior quality of the data that can be obtained at n_TOF will allow on one side a better characterization of s-process nucleosynthesis and on the other side a more accurate material balance in systems for transmutation of nuclear waste, given that this radioactive isotope is widely present in fission products.

  11. 89Zr-Cobalamin PET Tracer

    Kuda-Wedagedara, Akhila N W; Workinger, Jayme L; Nexo, Ebba

    2017-01-01

    Vitamin B12, or cobalamin (Cbl), is an essential nutrient. Acquisition, transport, and cellular internalization of Cbl are dependent on specific binding proteins and associated receptors. The circulating transport protein transcobalamin (TC) promotes cellular uptake via binding to specific......-Cbl (CN-Cbl). In vitro studies employing the CD320 receptor-positive breast cancer cell line MDA-MB-453 showed a 6- to 10-fold greater uptake of 89Zr-Cbl when compared with the uptake in the presence of 200-fold excess of CN-Cbl at 37 °C. We used nude mice with MDA-MB-453 tumors to study the feasibility...

  12. Band gap tuning of amorphous Al oxides by Zr alloying

    Canulescu, S., E-mail: stec@fotonik.dtu.dk; Schou, J. [Department of Photonics Engineering, Technical University of Denmark, 4000 Roskilde (Denmark); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus (Denmark); Borca, C. N.; Piamonteze, C. [Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Rechendorff, K.; Nielsen, L. P.; Almtoft, K. P. [Danish Technological Institute, Kongsvang Alle 29, 8000 Aarhus (Denmark); Gudla, V. C.; Bordo, K.; Ambat, R. [Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs-Lyngby (Denmark)

    2016-08-29

    The optical band gap and electronic structure of amorphous Al-Zr mixed oxides with Zr content ranging from 4.8 to 21.9% were determined using vacuum ultraviolet and X-ray absorption spectroscopy. The light scattering by the nano-porous structure of alumina at low wavelengths was estimated based on the Mie scattering theory. The dependence of the optical band gap of the Al-Zr mixed oxides on the Zr content deviates from linearity and decreases from 7.3 eV for pure anodized Al{sub 2}O{sub 3} to 6.45 eV for Al-Zr mixed oxides with a Zr content of 21.9%. With increasing Zr content, the conduction band minimum changes non-linearly as well. Fitting of the energy band gap values resulted in a bowing parameter of ∼2 eV. The band gap bowing of the mixed oxides is assigned to the presence of the Zr d-electron states localized below the conduction band minimum of anodized Al{sub 2}O{sub 3}.

  13. Synthesis of polyaniline/ZrO2 nanocomposites and their ...

    actions and nanoscale dimensions [9–11]. The morphology .... The reaction was allowed to proceed for 12 h. At the end of the reaction, PANI/ZrO2 composite formed was collected .... which is free to move along the chain, whereas the bound charges .... As men- tioned earlier, ZrO2 has the wide range of applications, which.

  14. Facile combustion synthesis of novel CaZrO 3

    Abstract. A facile sol–gel combustion route was reported for the direct preparation of CaZrO3:Eu3+ and CaZrO3:Eu3+, Gd3+. The obtained deposits were characterized by XRD, TGA-DSC, SEM, EDS, PL measurements and microscope fluorescence. When the Gd3+ ions were introduced in this compound, the emissions of ...

  15. Zr-based conversion coatings for multi-metal substrates

    Cerezo Palacios, J.M.

    2015-01-01

    In this PhD work, a new surface treatment based on the application of Zr-based conversion coatings by immersion in a Cu containing Zr-based conversion solution was investigated as a replacement of the traditional phosphating process for the automotive industry. Nowadays most of the cars are made of

  16. Can we trust module-respect heuristics?

    Mo, Yuchang

    2013-01-01

    BDD (Binary Decision Diagrams) have proven to be a very efficient tool to assess Fault Trees. However, the size of BDD, and therefore the efficiency of the whole methodology, depends dramatically on the choice of variable ordering. The determination of the best variable ordering is intractable. Therefore, heuristics have been designed to select reasonably good variable orderings. One very important common feature for good static heuristics is to respect modules. In this paper, the notion of module-respect is studied in a systematic way. It is proved that under certain condition there always exists an optimal ordering that respects modules. This condition is that for each module there is always a smallest module BDD and each included module variable appears only once. On the other hand, it is shown that for the trees not satisfying the above sufficient condition the optimal orderings may not be able to be directly generated using module-respect heuristics, even when the shuffling strategy is used.

  17. Freedom of Expression, Deliberation, Autonomy and Respect

    Rostbøll, Christian F.

    2011-01-01

    This paper elaborates on the deliberative democracy argument for freedom of expression in terms of its relationship to different dimensions of autonomy. It engages the objection that Enlightenment theories pose a threat to cultures that reject autonomy and argues that autonomy-based democracy is not only compatible with but necessary for respect for cultural diversity. On the basis of an intersubjective epistemology, it argues that people cannot know how to live on mutually respectful terms w...

  18. Ombud's Corner: Respect in the workplace

    Sudeshna Datta-Cockerill

    2014-01-01

    Launched in a previous issue of the Bulletin (see here), the 'Respect@CERN' campaign has triggered some rich and varied reactions, and contributions received from colleagues have covered a wide range of themes that extend from the basic “golden rule of treating others as you would have them treat you” to some very specific observations of respectful behaviour in the CERN context.   “To me, respect is the core of all relationships, all exchanges: we cannot work together and achieve results without it,” says one colleague, while another underlines the equally important dimension of projecting and preserving one’s own self-respect where “whether or not we sleep well at night depends on whether or not we feel that we have been true to ourselves that day”. Respect in the workplace is different from everyday respect in that it is based on an “earned privilege where each colleague has been selected for ...

  19. Thermoluminescent dosimetry of UV light using ZrO2:Gd films

    Flores D, R.C.; Rivera M, T.; Azorin N, J.; Falcony G, C.; Garcia H, M.; Martinez S, E.

    2002-01-01

    The samples used for the study are films of zirconium oxide activated with gadolinium (ZrO 2 :Gd) deposited in a glass substrate of square shape, whose dimensions are 1.5 mm thickness and 5 x 5 mm. The Tl curve of ZrO 2 :Gd presented two peaks in 110 and 290 Centigrade degrees. The thermoluminescent response depending on the wavelength presented a maximum in 270 nm. The treatment of optimum thermal erased was obtained for a temperature of 250 Centigrade degrees during 10 minutes. The irradiation time was realized in an interval of 1 to 75 minutes presenting its linear response until a time of 60 minutes. The recurring of the Tl response presented a variation of 1.38% with respect to the average. The fade out of the stored information in the material is 11.11% of standard deviation by a stored period of 7 days in normal working conditions. (Author)

  20. The electrical conductivity of CuCrZr alloy after SPD processing

    Lipińska, M; Bazarnik, P; Lewandowska, M

    2014-01-01

    CuCrZr alloys exhibit very good relation between mechanical properties and electrical conductivity. However, for its use in some advanced applications improvement of mechanical strength while preserving high electrical conducting is required. Therefore, in this work a CuCrZr alloy was subjected to a series of thermo-mechanical treatments, including solution annealing and water quenching, SPD processing (using hydrostatic extrusion and ECAP) as well as aging in order to improve mechanical strength. The influence of these processing procedures on microstructure features and mechanical properties was determined by TEM observation and microhardness measurements, respectively. Electrical conductivity of the samples was measured by four-points method. The results have shown that it is possible to improve mechanical strength while preserving good electrical conductivity by a proper combination of SPD processing and heat treatment

  1. irradiation growth in annealed Zr2.5wt%Nb at 3530K

    Rogerson, A.; Murgatroyd, R.A.

    1978-10-01

    Zr 2.5wt%Nb growth specimens have been irradiated at 353 0 K to a fast neutron dose of approximately 4.0 x 10 25 n/m 2 . Specimens were taken from the longitudinal and transverse directions of a nominally annealed, seam-welded tube and irradiated in both the stress relieved and fully annealed conditions. Growth in these specimens is characterised by large positive and negative strains in the longitudinal and transverse directions respectively, with dimensional changes in weld material exhibiting intermediate growth behaviour. The results are compared with growth data on both annealed and cold worked Zircaloy-2 at 353 0 K and discussed in terms of the effect of texture, grain size, and cold work on irradiation growth. It is concluded that the continuation of growth to high doses in annealed Zr-2.5wt%Nb at 353 0 K results from interstitial induced dislocation climb with vacancies diffusing to grain boundaries. (author)

  2. A quantum mechanical study of La-doped Pb(Zr,Ti)O{sub 3}

    Stashans, Arvids [Grupo de Fisica de Cristales, Escuela de Electronica y Telecomunicaciones, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador)]. E-mail: arvids@utpl.edu.ec; Maldonado, Frank [Grupo de Fisica de Cristales, Escuela de Electronica y Telecomunicaciones, Universidad Tecnica Particular de Loja, Apartado 11-01-608, Loja (Ecuador)

    2007-04-15

    Lanthanum-modified Pb(Zr,Ti)O{sub 3} (PZT) crystals have been investigated applying a quantum-mechanical approach based on the Hartree-Fock theory. A morphotropic phase boundary (MPB), PbZr{sub 0.53}Ti{sub 0.47}O{sub 3}, of the crystal was considered throughout the study. The obtained results show the outward atomic displacements with respect to the La impurity within the defective region and also the increase of covalent nature in the chemical bonding of the material. These outcomes are discussed and analyzed in light of the available experimental data. The occurrence of Jahn-Teller self-trapped electron polarons is predicted in the present report.

  3. A quantum mechanical study of La-doped Pb(Zr,Ti)O3

    Stashans, Arvids; Maldonado, Frank

    2007-01-01

    Lanthanum-modified Pb(Zr,Ti)O 3 (PZT) crystals have been investigated applying a quantum-mechanical approach based on the Hartree-Fock theory. A morphotropic phase boundary (MPB), PbZr 0.53 Ti 0.47 O 3 , of the crystal was considered throughout the study. The obtained results show the outward atomic displacements with respect to the La impurity within the defective region and also the increase of covalent nature in the chemical bonding of the material. These outcomes are discussed and analyzed in light of the available experimental data. The occurrence of Jahn-Teller self-trapped electron polarons is predicted in the present report

  4. Gamma decay of pygmy states in 90,94Zr from inelastic scattering of light ions

    Crespi, F. C. L.; Bracco, A.; Tamii, A.; Blasi, N.; Camera, F.; Wieland, O.; Aoi, N.; Balabanski, D.; Bassauer, S.; Brown, A. S.; Carpenter, M. P.; Carroll, J. J.; Ciemala, M.; Czeszumska, A.; Davies, P. J.; Donaldson, L.; Fang, Y.; Fujita, H.; Gey, G.; Hoang, T. H.; Ichige, N.; Ideguchi, E.; Inoue, A.; Isaak, J.; Iwamoto, C.; Jenkins, D. G.; Jin, O. H.; Klaus, T.; Kobayashi, N.; Koike, T.; Krzysiek, M.; Raju, M. Kumar; Liu, M.; Maj, A.; Montanari, D.; Morris, L.; Noji, S.; Pickstone, S. G.; Savran, D.; Spieker, M.; Steinhilber, G.; Sullivan, C.; Wasilewska, B.; Werner, V.; Yamamoto, T.; Yamamoto, Y.; Zhou, X.; Zhu, S.

    2018-05-01

    We performed experiments to study the low-energy part of the E1 response (Pygmy Dipole Resonance) in 90,94Zr nuclei, by measuring the (p,p’γ) and (α,α’γ) inelastic scattering reactions at energies Ebeam,p = 80 MeV and Ebeam,α = 130 MeV respectively. The inelastically scattered particles were measured by employing the high-resolution spectrometer Grand Raiden. The gamma-rays emitted following the de-excitation of the Zr target nuclei were detected using both the clover type HPGe detectors of the CAGRA array and the large volume LaBr3:Ce scintillation detectors from the HECTOR+ array. Some preliminary results are presented here.

  5. Effect of metallurgical factors on the oxidation of Zr - 1% Nb Alloy

    Soliman, H.M.

    1979-01-01

    The importance of study of the oxidation behaviour of zirconium and its niobium alloys arises from their suitability as cladding and structural materials in nuclear reactors and their use in oxidizing conditions. This work includes the oxidation behaviour of Zr - 1%Nb in both air and steam, and to less extent, zirconium was investigated in air. The effect of 1%Nb, oxidizing medium, fluoride ions contamination and thermal cycling on the oxidation behaviour has been investigated using weight gain, plastic deformation generated during oxidation, electron microscopy , metallography and X- ray techniques. The kinetics of oxidation of Zr-1%Nb alloy have been studied in the temperature range 500 - 1200 degree C and 500 - 900 degree C in both air and steam, respectively. The oxidation rate increases with temperature, Initially, the reaction proceeds with a decreasing rate ( mainly parabolic) followed by transition to a linear or acceleration, indicating breakaway. As the oxidation temperature increases, the time to breakaway transition decreases

  6. Comparative study of local atomic structures in Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) metallic glasses

    Huang, Yuxiang [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Huang, Li, E-mail: huangl@sustc.edu.cn [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Wang, C. Z.; Ho, K. M. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Department of Physics, Iowa State University, Ames, Iowa 50011 (United States); Kramer, M. J. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-11-21

    Extensive analysis has been performed to understand the key structural motifs accounting for the difference in glass forming ability in the Zr-Cu and Zr-Ni binary alloy systems. Here, the reliable atomic structure models of Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) are constructed using the combination of X-ray diffraction experiments, ab initio molecular dynamics simulations and a constrained reverse Monte Carlo method. We observe a systematic variation of the interatomic distance of different atomic pairs with respect to the alloy composition. The ideal icosahedral content in all samples is limited, despite the high content of five-fold symmetry motifs. We also demonstrate that the population of Z-clusters in Zr{sub 2}Cu glass is much higher than that in the Zr{sub 2}Ni and Zr{sub 2}Cu{sub 0.5}Ni{sub 0.5} samples. And Z12 〈0, 0, 12, 0〉 Voronoi polyhedra clusters prefer to form around Cu atoms, while Ni-centered clusters are more like Z11 〈0, 2, 8, 1〉 clusters, which is less energetically stable compared to Z12 clusters. These two different structural properties may account for the higher glass forming ability of Zr{sub 2}Cu alloy than that of Zr{sub 2}Ni alloy.

  7. The corrosion behaviour of Zr3Al-based alloys

    Murphy, E.V.; Wieler, R.

    1977-07-01

    The corrosion resistance of several zirconium-aluminum alloys with aluminum contents ranging from 7.6 to 9.6 wt% was examined in 300 deg C and 325 deg C water, 350 deg C and 400 deg C steam and in air and wet CO 2 at 325 deg C and 400 deg C. In the transformed alloys there are three phases present, αZr, Zr 2 Al and Zr 3 Al of which the αZr phase is the least corrosion resistant. The most important factor controlling the corrosion behaviour of these alloys was found to be the size, distribution and amount of the αZr phase in the transformed alloys, which in turn was dependent upon the microstructural scale of the untransformed alloys

  8. ZrC zone structure and features of electronic structure of solid solutions on the base ZrC, ZrN, TiC and TiN

    Mokhracheva, L.P.; Gel'd, P.V.; Tskhaj, V.A.

    1983-01-01

    The results of ZrC zone structure calculation conducted using the strong bond method in the three-centre variant are given. Essentially higher degree of M-C chemical bond ionicity than in TiC is shown to take place for it. Solid solution formation in TiC-ZrC, TiN-ZrC and ZrC-ZrN systems differing from TiC-TiN, TiN-ZrN and TiC-TiN is stated to be followed by essential deformation of component zone structures that, obviously, should prevent formation of solid solutions without vacancies in sublatices in these systems

  9. Effect of Nb aggregates on Zr2Fe

    Ramos, Cinthia P.

    2001-01-01

    The binary Zr-Fe phase diagram revision, performed by Arias et al., accepted the intermetallic Zr 2 Fe crystalline structure as tetragonal and determined that the presence of a third element like oxygen, nitrogen or carbon, stabilizes a cubic phase. Nevitt et al. studying Ti, Zr and Hf alloys with transition metals as second or third element and ternary systems with oxygen as third element, systematized the occurrence of phases with a cubic Ti 2 Ni type crystalline structure. From previous studies in the Zr-Nb-Fe system, it is an agreed fact that Nb presence in the Zr 2 Fe intermetallic stabilizes a cubic Ti 2 Ni type phase. The purpose of the present work is to determine the stability range of the Zr 2 Fe intermetallic with Nb contents, the existence range of the ternary cubic Ti 2 Ni type phase (designated Λ) and the corresponding two-phase region. We analyze as cast and heat treated (800 C degrees) Zr-Nb-Fe alloys with 35 atomic % Fe and Nb contents between 0.5 and 15 atomic %. The determination and characterization of the phases is made by optical and scanning electron microscopy, X-ray diffraction microprobe analysis and Moessbauer Spectroscopy. Joining these techniques together it is found, among many other things, that the Zr 2 Fe phase would accept up to around 0.5 atomic % Nb in solution and that the two-phase region Zr 2 Fe+Λ would be stable in the (0.5 - 3.5) Nb atomic % range. It is proposed as well a 800 C degrees section of the ternary (Zr-Nb-Fe) in the studied region. (author) [es

  10. Interface investigation of solution processed high- κ ZrO2/Si MOS structure by DLTS

    Kumar, Arvind; Mondal, Sandip; Rao, Ksr Koteswara

    The interfacial region is dominating due to the continuous downscaling and integration of high- k oxides in CMOS applications. The accurate characterization of high- k oxides/semiconductor interface has the significant importance towards its usage in memory and thin film devices. The interface traps at the high - k /semiconductor interface can be quantified by deep level transient spectroscopy (DLTS) with better accuracy in contrast to capacitance-voltage (CV) and conductance technique. We report the fabrication of high- k ZrO2 films on p-Si substrate by a simple and inexpensive sol-gel spin-coating technique. Further, the ZrO2/Si interface is characterized through DLTS. The flat-band voltage (VFB) and the density of slow interface states (oxide trapped charges) extracted from CV characteristics are 0.37 V and 2x10- 11 C/cm2, respectively. The activation energy, interface state density and capture cross-section quantified by DLTS are EV + 0.42 eV, 3.4x1011 eV- 1 cm- 2 and 5.8x10- 18 cm2, respectively. The high quality ZrO2 films own high dielectric constant 15 with low leakage current density might be an appropriate insulating layer in future electronic application. The low value of interface state density and capture cross-section are the indication of high quality interface and the defect present at the interface may not affect the device performance to a great extent. The DLTS study provides a broad understanding about the traps present at the interface of spin-coated ZrO2/Si.

  11. Characterization of laves phases in the pseudobinary Zr Cr2-Zr Fe2 system by Moessbauer spectroscopy

    Kanter, F.L. de; Badler, C.S.; Granovski, M.; Arias, D.

    1988-01-01

    57 Fe Moessbauer spectroscopy together with XRD and optical metallography were used to verify the two phase boundaries of the ZrCr 2 -ZrFe 2 pseudobinary phase diagram. Samples with adequate ternary and binary composition, treated at 1450 0 C, were studied. Experimental results indicate that in some cases the two phase boundaries should be modified. (author)

  12. Educating student midwives around dignity and respect.

    Hall, Jenny S; Mitchell, Mary

    2017-06-01

    There is currently limited information available on how midwifery students learn to provide care that promotes dignity and respect. In recent years the importance of dignity in healthcare and treating people with respect has received considerable emphasis in both a national and international context. The aim of this discussion paper is to describe an educational workshop that enables learning to promote dignity and respect in maternity care. An interactive workshop, using different creative methods as triggers for learning will be described. Provision of learning opportunities for students around dignity and respect is important to ensure appropriate care is provided in practice. The use of creative methods to inspire has contributed to deep learning within participants. An evaluation of the workshop illustrated how learning impacted on participants practice. Data to support this is presented in this paper. The use of creative teaching approaches in a workshop setting appears to provide an effective learning opportunity around dignified and respectful care. These workshops have evoked a deep emotional response for some participants, and facilitators must be prepared for this outcome to ensure a safe space for learning. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

  13. Freedom of Expression, Deliberation, Autonomy and Respect

    Rostbøll, Christian F.

    2011-01-01

    This paper elaborates on the deliberative democracy argument for freedom of expression in terms of its relationship to different dimensions of autonomy. It engages the objection that Enlightenment theories pose a threat to cultures that reject autonomy and argues that autonomy-based democracy...... is not only compatible with but necessary for respect for cultural diversity. On the basis of an intersubjective epistemology, it argues that people cannot know how to live on mutually respectful terms without engaging in public deliberation and develop some degree of personal autonomy. While freedom...... of expression is indispensable for deliberation and autonomy, this does not mean that people have no obligations regarding how they speak to each other. The moral insights provided by deliberation depend on the participants in the process treating one another with respect. The argument is related to the Danish...

  14. The preparation and testing of Nb-Zr and Nb-ZrO2 single crystals for deformation studies

    Botta Filho, W.J.; Christian, J.W.; Taylor, G.

    1987-01-01

    The difficulties to obtain adequate single crystals of Nb-Zr and Nb-ZrO 2 alloys for deformation studies are discussed. Low-temperature internal oxidation of Nb-Zr alloys followed by ageing at higher temperatures resulted in the precipitation of ZrO 2 particles. However, the effect of this treatment on the particles size and distribution and on the crystallographic structure of the particle was not completely understood. Compression tests in the temperature range 4.2K to 373K showed a small effect of zirconia particles on the mechanical properties of Nb-Zr solid solutions and a significative effect of the amount of oxygen remaining in solid solution after the oxidation treatment. (author) [pt

  15. Creating a culture of mutual respect.

    Kaplan, Kathryn; Mestel, Pamela; Feldman, David L

    2010-04-01

    The Joint Commission mandates that hospitals seeking accreditation have a process to define and address disruptive behavior. Leaders at Maimonides Medical Center, Brooklyn, New York, took the initiative to create a code of mutual respect that not only requires respectful behavior, but also encourages sensitivity and awareness to the causes of frustration that often lead to inappropriate behavior. Steps to implementing the code included selecting code advocates, setting up a system for mediating disputes, tracking and addressing operational system issues, providing training for personnel, developing a formal accountability process, and measuring the results. Copyright 2010 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  16. Microstructure and Phase Analysis in Mn-Al and Zr-Co Permanent Magnets

    Lucis, Michael J.

    In America's search for energy independence, the development of rare-earth free permanent magnets is one hurdle that still stands in the way. Permanent magnet motors provide a higher efficiency than induction motors in applications such as hybrid vehicles and wind turbines. This thesis investigates the ability of two materials, Mn-Al and Zr-Co, to fill this need for a permanent magnet material whose components are readily available within the U.S. and whose supply chain is more stable than that of the rare-earth materials. This thesis focuses on the creation and optimization of these two materials to later be used as the hard phase in nanocomposites with high energy products (greater than 10 MGOe). Mn-Al is capable of forming the pure L10 structure at a composition of Mn54Al43C3. When Mn is replaced by Fe or Cu using the formula Mn48Al43C3T6 the anisotropy constant is lowered from 1.3·107 ergs/cm3 to 1.0·107 ergs/cm3 and 0.8·10 7 ergs/cm3 respectively. Previous studies have reported a loss in magnetization in Mn-Al alloys during mechanical milling. The reason for this loss in magnetization was investigated and found to be due to the formation of the equilibrium beta-Mn phase of the composition Mn3Al2 and not due to oxidation or site disorder. It was also shown that fully dense Mn-Al permanent magnets can be created at hot pressing temperatures at or above 700°C and that the epsilon-phase to tau-phase transition and consolidation can be combined into a single processing step. The addition of small amounts of Cu to the alloy, 3% atomic, can increase the compaction density allowing high densities to be achieved at lower pressing temperatures. While the structure is still under debate, alloys at the composition Zr2Co11 in the Zr-Co system have been shown to have hard magnetic properties. This thesis shows that multiple structures exist at this Zr2Co11 composition and that altering the cooling rate during solidification of the alloy affects the ratio of the phase

  17. A chaotic quantum-behaved particle swarm approach applied to optimization of heat exchangers

    Mariani, Viviana Cocco; Klassen Duck, Anderson Rodrigo; Guerra, Fabio Alessandro; Santos Coelho, Leandro dos; Rao, Ravipudi Venkata

    2012-01-01

    Particle swarm optimization (PSO) method is a population-based optimization technique of swarm intelligence field in which each solution called “particle” flies around in a multidimensional problem search space. During the flight, every particle adjusts its position according to its own experience, as well as the experience of neighboring particles, using the best position encountered by itself and its neighbors. In this paper, a new quantum particle swarm optimization (QPSO) approach combined with Zaslavskii chaotic map sequences (QPSOZ) to shell and tube heat exchanger optimization is presented based on the minimization from economic view point. The results obtained in this paper for two case studies using the proposed QPSOZ approach, are compared with those obtained by using genetic algorithm, PSO and classical QPSO showing the best performance of QPSOZ. In order to verify the capability of the proposed method, two case studies are also presented showing that significant cost reductions are feasible with respect to traditionally designed exchangers. Referring to the literature test cases, reduction of capital investment up to 20% and 6% for the first and second cases, respectively, were obtained. Therefore, the annual pumping cost decreased markedly 72% and 75%, with an overall decrease of total cost up to 30% and 27%, respectively, for the cases 1 and 2, respectively, showing the improvement potential of the proposed method, QPSOZ. - Highlights: ► Shell and tube heat exchanger is minimized from economic view point. ► A new quantum particle swarm optimization (QPSO) combined with Zaslavskii chaotic map sequences (QPSOZ) is proposed. ► Reduction of capital investment up to 20% and 6% for the first and second cases was obtained. ► Annual pumping cost decreased 72% and 75%, with an overall decrease of total cost up to 30% and 27% using QPSOZ.

  18. Structural, vibrational and morphological properties of layered double hydroxides containing Ni{sup 2+}, Zn{sup 2+}, Al{sup 3+} and Zr{sup 4+} cations

    Bezerra, Débora M. [Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13566-590 São Carlos, SP (Brazil); Rodrigues, João E.F.S. [Instituto de Física de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970 São Carlos, SP (Brazil); Assaf, Elisabete M., E-mail: eassaf@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13566-590 São Carlos, SP (Brazil)

    2017-03-15

    Layered double hydroxides are anionic clays with formula [M{sup II}{sub 1−x} M{sup III}{sub x}(OH){sub 2}]{sup q+}[A{sup n−}]{sub q/n}·mH{sub 2}O, finding possible uses as catalyst support, adsorbents and so on. In this paper, we address the phase formation of layered double hydroxides containing Ni{sup 2+}, Zn{sup 2+}, Al{sup 3+} and Zr{sup 4+} cations, namely, NiZn-Al, NiZn-AlZr and NiZn-Zr compositions obtained by the coprecipitation method. Such systems were characterized by X-ray diffraction, confirming the phase formation for NiZn-Al and NiZn-AlZr samples. Infrared and Raman spectroscopies elucidated the anion and water molecules occurrence in the interlayer. Nitrogen physisorption (BET method) determined the presence of pores and specific surface area. The isotherm shapes were Type IV, according to the IUPAC, and represent a mesoporous structure. A morphological study was performed by means of scanning and transmission electron microscopies, and particle size values of 120, 131 and 235 nm for NiZn-Al, NiZn-AlZr and NiZn-Zr, respectively, were determined. Thermogravimetric analysis of the decomposition of the systems revealed that their complete disintegration occurred at ~ 450 °C and resulted in mixed oxides.

  19. Influences of hydrostatic pressure during casting and Pd content on as-cast phase in Zr-Al-Ni-Cu-Pd bulk alloys

    Kato, Hidemi; Inoue, Akihisa; Saida, Junji

    2004-01-01

    The influences of sample diameter (D), Pd content (x), and hydrostatic pressure (P) in a chamber during casting on the structure of as cast Zr 65 Al 7.5 Ni 10 Cu 17.5-x Pd x (x=10,17.5 at.%) bulk alloys were investigated. Zr 65 Al 7.5 Ni 10 Cu 7.5 Pd 10 and Zr 65 Al 7.5 Ni 10 Pd 17.5 alloys (D=3 mm) cast in a vacuum chamber (P∼4.0x10 -3 Pa) were mainly of the tetragonal-Zr 2 Ni equilibrium phase and nanosize icosahedral primary phase, respectively, while the same alloys cast in inert argon gas at atmospheric pressure (P∼0.1 MPa) were of the single glassy phase. Due to the higher cooling rate obtained by decreasing the sample diameter (D=2 mm) even in the vacuum chamber, the Zr 65 Al 7.5 Ni 10 Pd 17.5 alloy was still of the icosahedral phase, while the Zr 65 Al 7.5 Ni 10 Cu 7.5 Pd 10 alloy froze into a single glassy phase. These results indicate that the temperature- and time- transformation curves for the icosahedral and subsequent equilibrium phase formations in the alloy system shifts to a shorter time side with decreasing P, and the pressure sensitivity of the icosahedral phase formation increases with x

  20. TiZrNbTaMo high-entropy alloy designed for orthopedic implants: As-cast microstructure and mechanical properties.

    Wang, Shao-Ping; Xu, Jian

    2017-04-01

    Combining the high-entropy alloy (HEA) concept with property requirement for orthopedic implants, we designed a Ti 20 Zr 20 Nb 20 Ta 20 Mo 20 equiatomic HEA. The arc-melted microstructures, compressive properties and potentiodynamic polarization behavior in phosphate buffer solution (PBS) were studied in detail. It was revealed that the as-cast TiZrNbTaMo HEA consisted of dual phases with bcc structure, major bcc1 and minor bcc2 phases with the lattice parameters of 0.3310nm and 0.3379nm, respectively. As confirmed by nanoindentation tests, the bcc1 phase is somewhat harder and stiffer than the bcc2 phase. The TiZrNbTaMo HEA exhibited Young's modulus of 153GPa, Vickers microhardness of 4.9GPa, compressive yield strength of σ y =1390MPa and apparent plastic strain of ε p ≈6% prior to failure. Moreover, the TiZrNbTaMo HEA manifested excellent corrosion resistance in PBS, comparable to the Ti6Al4V alloy, and pitting resistance remarkably superior to the 316L SS and CoCrMo alloys. These preliminary advantages of the TiZrNbTaMo HEA over the current orthopedic implant metals in mechanical properties and corrosion resistance offer an opportunity to explore new orthopedic-implant alloys based on the TiZrNbTaMo concentrated composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Preparation and dielectric properties of Dy, Er-doped BaZr0.2Ti0.8O3 ceramics

    Hao Sue; Sun Liang; Huang Jinxiang

    2008-01-01

    Ba(Zr x Ti 1-x )O 3 nanopowders and ceramics with different Zr/Ti ratios of 1:9; 2:8; 2.5:7.5; 3.5:6.5 and 4:6 (x = 0.1, 0.2, 0.25, 0.35, 0.4) have been prepared by sol-gel technology using inorganic zirconium as raw materials, and Zr/Ti ratio of 2:8 is determined as the best one according to the measurements of dielectric properties. So the modified Ba(Zr 0.2 ,Ti 0.8 )O 3 ceramics doped by Dy and Er (the additive content is 0.10%, 0.15%, 0.20%, 0.30% and 0.50% molar ratio, respectively) have been prepared, and the effects of rare earth on the microstructure and dielectric properties of Ba(Zr 0.2 ,Ti 0.8 )O 3 ceramics have been studied. The experimental results show that the effect of Er is better than that of Dy in improving the dielectric properties of BaZr 0.2 Ti 0.8 O 3 ceramics. When the content of Er is 0.15 mol%, the dielectric constant is the highest of 12767, while the dielectric loss is lowered to 0.011; the frequency stabilities and the temperature dependence are also better, which is suitable for application in condenser field

  2. Stabilization effect of Zr and Ti additions on the ageing characteristics of Al-1 wt% Si alloy through a creep study

    Deaf, G.H.; Beshai, M.H.N.; Abd El Khalek, A.M.; Graiss, G. [Ain Shams Univ., Cairo (Egypt). Dept. of Physics; Kenawy, M.A. [Ain Shams Univ., Cairo (Egypt). Womens Coll.

    1997-12-31

    Al-1 wt% Si and Al-1 wt% Si-0.1 wt% Zr-0.1 wt% Ti alloys were used to trace the effect of Zr and Ti additions on the behaviour of the steady state creep. After solid solution treatment specimens of both alloys were aged at 623, 673, 723 and 773 K and creep tests were performed at room temperature by applying stresses of 60.0, 62.4, 64.7 and 67.1 MPa. The results showed a sound stabilization effect of Zr and Ti on the ageing characteristics of binary Al-1 wt% Si alloy. Values of the applied stress sensitivity parameter, m, obtained were in the range of (20-34) for Al-Si alloy and (14-19) for Al-Si-Zr-Ti alloy. Time to rupture was found to be strongly increased by Zr and Ti additions. The activation energies of the precipitation process involved were found to be 81.9 kJ/mole and 33.7 kJ/mole of the Al-Si and Al-Si-Zr-Ti alloys respectively. (orig.) 17 refs.

  3. Validation of Zr and Hf analysis contained on water phase using k_0-neutron activation analysis method

    Wisjachudin Faisa; Sutisna

    2010-01-01

    At conversion of Zr-sand to Zircon Oxide, the Hf content in product process should not be more than 100 ppm. While Zr and Hf are two elements that have a similar chemical property Hs, they are difficult to analyze by ordinary chemical analysis. One of reliable analytical method that can be used to quantify Zr and Hf is the instrumental neutron activation analysis. Related to this problem, a result of k_0-Instrumental Neutron Activation Analysis (k_0-INAA) on Zr and Hf (in aqueous phase) has been validated. A number of 200 µL SPEX Pure standard solution which have a concentration of 1 g/L pipeted into a cleaned micro vial, then dried at a temperature of 40°C for 24 hours. Samples, together with flux monitors, were irradiated simultaneously at 15 MW power (thermal neutron flux around 4.1 x 10"1"7n. m"-"2.s"-"1) for 30 minutes in the rabbit facility of GA. Siwabessy reactor. Counting of the irradiated sample have been done using a high resolution HPGe detector (FWHM = 1.9 keV at Eγ 1332.5 keV of "6"0Co,Peak to Compton ratio ~ 40). The analytical results showed a relative standard deviation (RSD) of Zr is 6.6 % with average uncertainty of 3.08 % and a detection limit of 0.1 mg, while RSD of Hf = 8.2 %, with average uncertainty of 8.04 % and a detection limit of 0.3 mg. Recovery obtained was 106,0 % and 96,0 % for Zr and Hf respectively. These results are relatively better compared to the previous result using the Standard Reference Material (SRM) 1633b Coal Fly Ash which have RSD Hf was 20.6 %. (author)

  4. Effects of Al content on structure and mechanical properties of hot-rolled ZrTiAlV alloys

    Liang, S.X.; Yin, L.X.; Che, H.W.; Jing, R.; Zhou, Y.K.; Ma, M.Z.; Liu, R.P.

    2013-01-01

    Highlights: • Phase structure is greatly dependent on the Al content. • Intermetallic compound will precipitates while Al content is over 6.9 wt%. • Equiaxed α-phase grains present in the hot-rolled alloy with 6.9 wt% Al. • Alloys with Al content from 3.3 wt% to 5.6 wt% have good mechanical properties. - Abstract: Zirconium alloys show attractive properties for astronautic applications where the most important factors are anti-irradiation, corrosion resistance, anti-oxidant, very good strength-to-weight ratio. The effects of Al content (2.2–6.9 wt%) on structure and mechanical properties of the hot-rolled ZrTiAlV alloy samples were investigated in this study. Each sample of the hot-rolled ZrTiAlV alloys with Al contents from 2.2 wt% to 5.6 wt% is composed of the α phase and β phase, meanwhile, the relative content of the α phase increased with the Al content. However, the (ZrTi) 3 Al intermetallic compound was observed as the Al content increased to 6.9 wt%. Changes of phase compositions and structure with Al content distinctly affected mechanical properties of ZrTiAlV alloys. Yield strength of the alloy with 2.2 wt% Al is below 200 MPa. As Al content increased to 5.6 wt%, the yield strength, tensile strength and elongation of the examined alloy are 1088 MPa, 1256 MPa and 8%, respectively. As Al content further increased to 6.9 wt%, a rapid decrease in ductility was observed as soon as the (ZrTi) 3 Al intermetallic compound precipitated. Results show that the ZrTiAlV alloys with Al contents between 3.3 wt% and 5.6 wt% have excellent mechanical properties

  5. Structural and morphological characterization of TiO{sub 2}-ZrO{sub 2} powders obtained by the polymeric precursors method; Caracterizacao estrutural e morfologica de pos de TiO{sub 2}-ZrO{sub 2} obtidos pelo metodo dos precursores polimericos

    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S., E-mail: m_aparecidaribeiro@yahoo.com.b [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Bernardi, M.I.B. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    This work aims to characterize the structure and morphology of TiO{sub 2}-ZrO{sub 2} powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO{sub 2} in the anatase form and a tetragonal phase of ZrO{sub 2}. The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO{sub 2} nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  6. Effects of TiN coating on the corrosion of nanostructured Ti-30Ta-xZr alloys for dental implants

    Kim, Won-Gi; Choe, Han-Cheol

    2012-01-01

    Electrochemical characteristics of a titanium nitride (TiN)-coated/nanotube-formed Ti-Ta-Zr alloy for biomaterials have been researched by using the magnetic sputter and electrochemical methods. Ti-30Ta-xZr (x = 3, 7 and 15 wt%) alloys were prepared by arc melting and heat treated for 24 h at 1000 °C in an argon atmosphere and then water quenching. The formation of oxide nanotubes was achieved by anodizing a Ti-30Ta-xZr alloy in H3PO4 electrolytes containing small amounts of fluoride ions at room temperature. Anodization was carried out using a scanning potentiostat, and all experiments were conducted at room temperature. The microstructure and morphology of nanotube arrays were characterized by optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The TiN coatings were obtained by the radio-frequency (RF) magnetron sputtering technique. The depositions were performed from pure Ti targets on Ti-30Ta-xZr alloys substrates. The corrosion properties of the specimens were examined using potentiodynamic test in a 0.9% NaCl solution by using potentiostat. The microstructures of Ti-30Ta-xZr alloys were changed from an equiaxed to a needle-like structure with increasing Zr content. The interspace between the nanotubes was approximately 20, 80 and 200 nm for Zr contents of 3, 7 and 15 wt%, respectively. The corrosion resistance of the TiN-coated on the anodized Ti-30Ta-xZr alloys was higher than that of the untreated Ti alloys, indicating a better protective effect.

  7. Respect for autonomy and technological risks

    Asveld, L.

    2008-01-01

    Technological developments can undermine the autonomy of the individual. Autonomy is one's ability to make and act upon decisions according to one's own moral framework. Respect for autonomy dictates that risks should not be imposed on the individual without her consent. Technological developments

  8. [Respect of patient's dignity in the hospital].

    Duguet, A-M

    2010-12-01

    Every code of ethics of health professionals in France considers the respect of dignity as a fundamental duty. The French 2002 Law on patient rights says that the person has the right to respect of dignity and of private life. After a presentation of the articles of ethics codes regarding dignity, this paper presents recommendations to deliver medical care in situations where dignity might be endangered such as for patients hospitalized in psychiatric services without consent, or for medical examination of prisoners or medical care to vulnerable patients unable to express their will, especially in palliative care or at the end of life. Respect of dignity after death is illustrated by the reflection conducted by the Espace Ethique de l'AP-HP (Paris area hospitals) and in the Chart of the mortuary yard. A survey of the patients' letters of complaint received by the emergency service of the Toulouse University Hospital showed that, in five years, there were 188 letters and 18 pointed out infringements to the dignity of the person. The health professional team is now aware of this obligation, and in the accreditation of the hospitals, the respect of dignity is one of the indicators of the quality of medical care.

  9. Nurturing the Respectful Community through Practical Life

    Bettmann, Joen

    2015-01-01

    Joen Bettmann's depiction of practical life exercises as character-building reveals how caring, careful, and independent work leads to higher self-esteem, more concern for others, better understanding for academic learning, and a self-nurturing, respectful classroom community. Particular aspects of movement and silence exercises bring out what…

  10. Determination of the dosimetric properties of ZrO2: Cu and it use in the ultraviolet radiation dosimetry

    Molina P, D.; Olvera T, L.; Azorin N, J.; Barrera S, M.; Soto E, A.M.; Rivera M, T.

    2006-01-01

    In this work the experimental results of studying the thermoluminescent characteristics (TL) of the zirconium oxide doped with copper (ZrO 2 : Cu) exposed to ultraviolet light of wavelength in the interval of 200-400 nm are presented. The material in powder form was prepared using the sol-gel method. The dosimetric characteristics studied includes the emission curve TL (curved TL), the thermoluminescent response in function of the wavelength, the minimum dose detectable and the lineality of the response. The TL response of the ZrO 2 : Cu in function of the wavelength presents two maxima, in 260 and 290 nm, respectively. The TL curve of the ZrO 2 : Cu showed two peaks, in 120 and 170 C, respectively, being its similar form for all the studied wavelengths. The response in function of the spectral irradiance results to be lineal in the interval from 160 to 2300 mJ/cm 2 . The obtained results when studying the TL properties of ZrO 2 : Cu exposed to the ultraviolet radiation show that it gathers dosimetric characteristics prominent to be used as an ultraviolet radiation dosemeter. (Author)

  11. Valence electron structure and properties of stabilized ZrO2

    LI JinPing; HAN JieOai; MENG SongHe; ZHANG XingHong

    2008-01-01

    To reveal the properties of stabilizers in ZrO2 on nanoscopic levels,the valence elec-tron structures of four stable ZrO2 phases and c-ZrO2 were analyzed on the basis of the empirical electron theory of solids and molecules.The results showed that the hybridization levels of Zr atoms in c-ZrO2 doped with Ca and Mg dropped from B17 to B13,the hybridization levels of Zr atoms in c-ZrO2 doped with Y and Ce dropped from B17 to B15,and that the four stabilizing atoms all made the hybridization levels of O atoms drop from level 4 to level 2.The numbers of covalent electrons in the strongest covalent bond in the descending order are c-ZrO2>ZrCeO2>ZrYOZrMgO>ZrCaO.The bond energies of the strongest covalent bond and the melting points of the solid solutions in the descending order are ZrCeO2>c-ZrO2>ZrYO>ZrMgO>ZrCaO.The percent-ages of the total number of covalent electrons in the descending order arec-ZrO2>ZrYO> ZrCeO2>ZrMgO> ZrCaO.From the above analysis,it can be concluded that the stabilizing degrees of the four stabilizers in the descending order are CaO> MgO>Y2O3>CeO2.

  12. Superconductivity and NMR investigations of amorphous Be-Nb-Zr and Be-Mo-Zr alloys

    Goebbels, J.; Lueders, K.; Freyhardt, H.C.; Reichelt, J.

    1981-01-01

    9 Be NMR investigations and measurements of the superconducting properties and the resistivity are reported for amorphous Besub(32.5)Nbsub(x)Zrsub(67.5-x) and Besub(32.5)Mosub(x)Zrsub(67.5-x) alloys (x = 2.5; 5; 7). Line width analysis suggests an enlarged Nb concentration around the Be sites for the Be-Nb-Zr alloys. Comparing the two types of alloys the Knight shifts are of the same order of magnitude whereas the Tsub(c) and Bsub(c) 2 (0) values are slightly smaller than for the Nb alloys. For Be-Nb-Zr Tsub(c) and K increases with the Nb content. The results are discussed in connection with the density of states N(Esub(F)). (orig.)

  13. Fractography of STIR casted Al-ZrO2 composites

    Baghchesara, M. A.; Abdizadeh, H.; Baharvandi, H. R.

    2009-01-01

    In this study, Al-ZrO 2 composites were produced by Vortex method using ZrO 2 powder with 1 micron average diameter as reinforce particles and Al-356 as the matrix metal. The melt composites were stirred for 13 minutes, then casted into a metallic mold. Different samples of 5, 10 and 15 volume percent of ZrO 2 , in different casting temperatures of 750, 850 and 950 d eg C were produced. The latter 2 casting temperatures are not a common practice but were chosen to enhance fluidity. Effects of volume percent of ZrO 2 particles and casting temperature on tensile strength, microstructure, and fracture surfaces of Al-ZrO 2 composites have been investigated. The highest tensile strength was achieved in the specimen containing 15 vol. % ZrO 2 produced at 750 d eg C which shows an increase of 60% in comparison to the Al-356 non-reinforced alloy. Microscopic investigations of fracture surfaces revealed that fracture in a brittle manner with little or no necking happening. By increasing ZrO 2 content and casting temperature, the composites fracture goes in a more severely brittle manner.

  14. Band gap tuning of amorphous Al oxides by Zr alloying

    Canulescu, Stela; Jones, N. C.; Borca, C. N.

    2016-01-01

    minimum changes non-linearly as well.Fitting of the energy band gap values resulted in a bowing parameter of 2 eV. The band gap bowing of themixed oxides is assigned to the presence of the Zr d-electron states localized below the conduction bandminimum of anodized Al2O3.......The optical band gap and electronic structure of amorphous Al-Zr mixed oxides, with Zr content ranging from4.8 to 21.9% were determined using vacuum ultraviolet (VUV) and X-ray absorption spectroscopy (XAS). Thelight scattering by the nano-porous structure of alumina at low wavelengths...... was estimated based on the Miescattering theory. The dependence of the optical band gap of the Al-Zr mixed oxides on Zr content deviatesfrom linearity and decreases from 7.3 eV for pure anodized Al2O3 to 6.45 eV for Al-Zr mixed oxide with Zrcontent of 21.9%. With increasing Zr content, the conduction band...

  15. Structural investigation of Fe(Cu)ZrB amorphous alloy

    Duhaj, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Matko, I. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Svec, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Sitek, J. [Department of Nuclear Physics and Technology, Slovak Technical University, 81219 Bratislava (Slovakia); Janickovic, D. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav

    1996-07-01

    The crystallization process in Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} alloys. In both alloys the first crystallization begins with the formation of nanocrystalline {alpha}-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of {alpha}-Fe and dispersed Fe{sub 23}Zr{sub 6} phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  16. Structural investigation of Fe(Cu)ZrB amorphous alloy

    Duhaj, P.; Janickovic, D.

    1996-01-01

    The crystallization process in Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline α-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of α-Fe and dispersed Fe 23 Zr 6 phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  17. Freedom of Expression, Deliberation, Autonomy, and Respect

    Rostbøll, Christian Fogh

    for freedom of expression in terms of its relationship to different dimensions of autonomy. In response to the objection that Enlightenment theories pose a threat to cultures that reject autonomy, it is argued that autonomy-based democracy is not only compatible with but necessary for respect for cultural......The strongest versions of the democracy argument for freedom of expression rely on the deliberative conception of democracy. Deliberative democracy entails both an ideal of political autonomy and of autonomous preference formation. This paper elaborates the deliberative democracy argument...... diversity. On the basis of an intersubjective epistemology, I argue that citizens cannot know how to live on mutually respectful terms without engaging in public deliberation. Moreover, to be successful deliberation must foster some degree of personal autonomy, at least the ability to distinguish what...

  18. Dynamic behaviors of a Zr-based bulk metallic glass under ramp wave and shock wave loading

    Binqiang Luo

    2015-06-01

    Full Text Available Dynamic behaviors of Zr51Ti5Ni10Cu25Al9 bulk metallic glass were investigated using electric gun and magnetically driven isentropic compression device which provide shock and ramp wave loading respectively. Double-wave structure was observed under shock compression while three-wave structure was observed under ramp compression in 0 ∼ 18GPa. The HEL of Zr51Ti5Ni10Cu25Al9 is 8.97 ± 0.61GPa and IEL is 8.8 ± 0.3GPa, respectively. Strength of Zr51Ti5Ni10Cu25Al9 estimated from HEL is 5.0 ± 0.3GPa while the strength estimated from IEL is 3.6 ± 0.1GPa. Shock wave velocity versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under shock compression appears to be bilinear and a kink appears at about 18GPa. The Lagrangian sound speed versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under ramp wave compression exhibits two discontinuances and are divided to three regions: elastic, plastic-I and plastic-II. The first jump-down occurs at elastic-plastic transition and the second appears at about 17GPa. In elastic and plastic-I regions, Lagrangian sound speed increases linearly with particle velocity, respectively. Characteristic response of sound speed in plastic-I region disagree with shock result in the same pressure region(7GPa ∼ 18GPa, but is consistent with shock result at higher pressure(18-110GPa.

  19. Effect of the Zr elements with thermal properties changes of U-7Mo-xZr/Al dispersion fuel

    Supardjo; Agoeng Kadarjono; Boybul; Aslina Br Ginting

    2016-01-01

    Thermal properties data of nuclear fuel is required as input data to predict material properties change phenomenon during the fabrication process and irradiated in a nuclear reactor. Study the influence of Zr element in the U-7Mo-xZr/Al (x = 1%, 2% and 3%) fuel dispersion to changes in the thermal properties at various temperatures have been stiffened. Thermal analysis includes determining the melting temperature, enthalpy, and phase changes made using Differential Thermal Analysis (DTA) in the temperature range between 30 °C up to 1400 °C, while the heat capacity of U-7Mo-xZr alloy and U-7Mo-xZr/Al dispersion fuel using Differential Scanning Calorimeter (DSC) at room temperature up to 450 °C. Thermal analyst data DTA shows that Zr levels of all three compositions showed a similar phenomenon. At temperatures between 565.60 °C - 584.98 °C change becomes α + δ to α + γ phase and at 649.22 °C – 650.13 °C happen smelting Al matrix Occur followed by a reaction between Al matrix with U-7Mo-xZr on 670.38 °C - 673.38 °C form U (Al, Mo)x Zr. Furthermore a phase change α + β becomes β + γ Occurs at temperatures 762.08 °C - 776.33 °C and diffusion between the matrix by U-7Mo-xZr/Al on 853.55 °C - 875.20 °C. Every phenomenon that Occurs, enthalpy posed a relative stable. Consolidation of uranium Occur in 1052.42 °C - 1104.99 °C and decomposition reaction of U (Al, Mo)x and U (Al, Zr)_x becomes (UAl_4, UAl_3, UAl_2), U-Mo, and UZr on 1328,34 °C - 1332,06 °C , The existence of Zr in U-Mo alloy increases the heat capacity of the U-7Mo-xZr/Al, dispersion fuel and the higher heat capacity of Zr levels increased due to interactions between the atoms of Zr with Al matrix so that the heat absorbed by the fuel increase. (author)

  20. Understanding Mechanical Design with Respect to Manufacturability

    Mondell, Skyler

    2010-01-01

    At the NASA Prototype Development Laboratory in Kennedy Space Center, Fl, several projects concerning different areas of mechanical design were undertaken in order to better understand the relationship between mechanical design and manufacturabiIity. The assigned projects pertained specifically to the NASA Space Shuttle, Constellation, and Expendable Launch Vehicle programs. During the work term, mechanical design practices relating to manufacturing processes were learned and utilized in order to obtain an understanding of mechanical design with respect to manufacturability.

  1. Effect of preparation techniques on creep characteristics of the Zr-2. 5% Nb alloy at temperatures of 673 to 823 K

    Pahutova, M; Kreici, J; Polesna, M [Ceskoslovenska Akademie Ved, Brno. Ustav Fyzikalni Metalurgie

    1976-01-01

    The effect of the initial raw material - zirconium sponge or zirconium iodide - on some creep and stres-strain properties was studied on Zr-2.5%Nb alloy by a stress-strain test at constant crosshead speed and by strain-rate sensitivity testing. Dependence of the creep characteristics on cooling conditions after solution treatment was examined. Alloy made from Zr-sponge was used for measurement of steady-state creep rate on time to fracture dependence and steady-state creep rate on time to fracture with respect to the angle between rolling direction of alloy sheets and tensile axis. Transmission electron microscopy was used for structure study of both alloys after different heat treatment. Higher creep strength of the alloy made from iodide zirconium (after respective heat treatment) than that of the alloy made from Zr-sponge is discussed. Oxygen content and its effect on structural changes during heat treatment seems to be responsible for higher creep strength of the first alloy. On the other hand the difference of respective creep strengths is not so significant as to justify production of Zr-2.5%Nb alloy and perhaps of future high-strength Zr alloys (for applications in structural components in reactors in the temperature range of 673 to 773 K) from iodide zirconium. Results of creep and stress-strain (short time) testing are briefly discussed.

  2. The effect of preparation techniques on creep characteristics of the Zr-2.5% Nb alloy at temperatures of 673 to 823 K

    Pahutova, M.; Krejci, J.; Polesna, M.

    1976-01-01

    The effect of the initial raw material - zirconium sponge or zirconium iodide - on some creep and stres-strain properties was studied on Zr-2.5%Nb alloy by a stress-strain test at constant crosshead speed and by strain-rate sensitivity testing. Dependence of the creep characteristics on cooling conditions after solution treatment was examined. Alloy made from Zr-sponge was used for measurement of steady-state creep rate on time to fracture dependence and steady-state creep rate on time to fracture with respect to the angle between rolling direction of alloy sheets and tensile axis. Transmission electron microscopy was used for structure study of both alloys after different heat treatment. Higher creep strength of the alloy made from iodide zirconium (after respective heat treatment) than that of the alloy made from Zr-sponge is discussed. Oxygen content and its effect on structural changes during heat treatment seems to be responsible for higher creep strength of the first alloy. On the other hand the difference of respective creep strengths is not so significant as to justify production of Zr-2.5%Nb alloy and perhaps of future high-strength Zr alloys (for applications in structural components in reactors in the temperature range of 673 to 773 K) from iodide zirconium. Results of creep and stress-strain (short time) testing are briefly discussed. (author)

  3. Nurses’ commitment to respecting patient dignity

    Raee, Zahra; Abedi, Heidarali; Shahriari, Mohsen

    2017-01-01

    Background: Although respecting human dignity is a cornerstone of all nursing practices, industrialization has gradually decreased the attention paid to this subject in nursing care. Therefore, the present study aimed to investigate nurses’ commitment to respecting patient dignity in hospitals of Isfahan, Iran. Methods: This descriptive-analytical study was conducted in hospitals of Isfahan. Overall, 401 inpatients were selected by cluster sampling and then selected simple random sampling from different wards. Data were collected through a questionnaire containing the components of patient dignity, that is, patient-nurse relationships, privacy, and independence. All items were scored based on a five-point Likert scale. The collected data were analyzed using descriptive statistics and Chi-square tests. P < 0.05 were considered significant in all analyses. Findings: Most patients (91%) scored their relationships with nurses as good. Moreover, 91.8% of the participants described privacy protection as moderate/good. Only 6.5% of the subjects rated it as excellent. The majority of the patients (84.4%) believed their independence was maintained. These subjects also approved of taking part in decision-making. Conclusion: According to our findings, nurses respected patient dignity to an acceptable level. However, the conditions were less favorable in public hospitals and emergency departments. Nursing authorities and policy makers are thus required to introduce appropriate measures to improve the existing conditions. PMID:28546981

  4. Nurses' commitment to respecting patient dignity.

    Raee, Zahra; Abedi, Heidarali; Shahriari, Mohsen

    2017-01-01

    Although respecting human dignity is a cornerstone of all nursing practices, industrialization has gradually decreased the attention paid to this subject in nursing care. Therefore, the present study aimed to investigate nurses' commitment to respecting patient dignity in hospitals of Isfahan, Iran. This descriptive-analytical study was conducted in hospitals of Isfahan. Overall, 401 inpatients were selected by cluster sampling and then selected simple random sampling from different wards. Data were collected through a questionnaire containing the components of patient dignity, that is, patient-nurse relationships, privacy, and independence. All items were scored based on a five-point Likert scale. The collected data were analyzed using descriptive statistics and Chi-square tests. P < 0.05 were considered significant in all analyses. Most patients (91%) scored their relationships with nurses as good. Moreover, 91.8% of the participants described privacy protection as moderate/good. Only 6.5% of the subjects rated it as excellent. The majority of the patients (84.4%) believed their independence was maintained. These subjects also approved of taking part in decision-making. According to our findings, nurses respected patient dignity to an acceptable level. However, the conditions were less favorable in public hospitals and emergency departments. Nursing authorities and policy makers are thus required to introduce appropriate measures to improve the existing conditions.

  5. Zr alkoxide chain effect on the sol-gel synthesis of lithium metazirconate

    Pfeiffer, Heriberto; Bosch, Pedro; Bulbulian, Silvia

    2003-01-01

    Lithium metazirconate (Li 2 ZrO 3 ) was synthesized by the sol-gel method, using four different Zr alkoxides: zirconium ethoxide, zirconium iso-propoxide, zirconium propoxide and zirconium butoxide. The syntheses were made under two different catalytic regimes, acid and basic. The resulting powders were mixtures of Li 2 ZrO 3 and ZrO 2 . The best yield of Li 2 ZrO 3 (100%) was obtained when the sol-gel reaction was developed with lithium methoxide and zirconium ethoxide under acid catalysis regime. This study establishes that, for base-catalyzed reactions the ZrO 2 formation decreases when the alkyl-chain increases in the alkoxides. By contrast, for acid-catalyzed reactions the ZrO 2 formation increases as the alkyl-chain increases. Finally, when Zr propoxide and Zr iso-propoxide were used, the Li 2 ZrO 3 amounts were different due to steric effects

  6. Superconductivity and spin fluctuations in M-Zr metallic glasses (M = Cu, Ni, Co, and Fe)

    Altounian, Z.; Strom-Olsen, J.O.

    1983-01-01

    The superconducting transition temperature, upper critical field, and magnetic susceptibility have been measured in four binary metallic glass systems: Cu-Zr, Ni-Zr, Co-Zr, and Fe-Zr. For each alloy system, a full and continuous range of Zr-rich compositions accessible by melt spinning has been examined. For Cu-Zr, the range is 0.75>x>0.30; for Ni-Zr, 0.80>x>0.30; for Co-Zr, 0.80>x>0.48, and for Fe-Zr, 0.80>x>0.55 (x being the concentration of Zr in at. %). The results show clearly the influence of spin fluctuations in reducing the superconducting transition temperature. The data have been successfully analyzed using a modified form of the McMillan equation together with expressions for the Stoner enhanced magnetic susceptibility and the Ginsburg-Landau-Abrikosov-Gor'kov expression for the upper critical field

  7. Hyperfine interactions and some thermomagnetic properties of amorphous FeZr(CrNbBCu alloys

    Łukiewska Agnieszka

    2017-06-01

    Full Text Available In this research, we studied the magnetic phase transition by Mössbauer spectroscopy and using vibrating sample magnetometer for amorphous Fe86-xZr7CrxNb2Cu1B4 (x = 0 or 6 alloys in the as-quenched state and after accumulative annealing in the temperature range 600-750 K. The Mössbauer investigations were carried out at room and nitrogen temperatures. The Mössbauer spectra of the investigated alloys at room temperature are characteristic of amorphous paramagnets and have a form of asymmetric doublets. However, at nitrogen temperature, the alloys behave like ferromagnetic amorphous materials. The two components are distinguished in the spectrum recorded at both room and nitrogen temperatures. The low field component in the distribution of hyperfine field induction shifts towards higher field with the annealing temperature. It is assumed that during annealing at higher temperature, due to diffusion processes, the grains of α-Fe are created in the area corresponding to this component. Both investigated alloys show the invar effect and the decrease of hyperfine field induction after annealing at 600 K for 10 min is observed. It is accompanied by the lowering of Curie temperature.

  8. One pot synthesized Li, Zr doped porous silica nanoparticle for low temperature CO2 adsorption

    Mani Ganesh

    2017-05-01

    Full Text Available Li, Zr doped porous silica was synthesized in one pot and investigated for low temperature CO2 adsorption. The synthesized nanoparticle was characterized by X-ray diffraction (XRD, N2 adsorption–desorption measurement, thermogravimetric analysis (TGA and scanning electron microscopy (SEM. The specific surface area, average pore diameter and pore volume were determined to be 962 m2/g, 2.3 nm and 0.56 cm3/g respectively. ICP-AES analysis revealed a metal content of 4 wt.% (Zr and 3.42 wt.% (Li. Their CO2 adsorption capacity was tested at room temperature and atmospheric pressure. An uptake of about 5 wt.% was observed and regenerable at a low temperature of 200 °C. This adsorption and desorption temperature of the sorbent is lower than the reported lithium silicate. The CO2 adsorption–desorption cyclic performance studies illustrated that Li, Zr doped porous silica is a recyclable, selective and potential sorbent for CO2 adsorption.

  9. Effect of nitrogen pressure on melting point of ZrNsub(x)

    Eronyan, M.A.; Avarbeh, R.G.; Nikol'skaya, T.A.

    1976-01-01

    The investigations were performed in an airtight water-cooled chamber in the nitrogen pressure range of 10 -3 -100 atm and at 2600-3700 0 C. The nitrogen pressure in the range 10 -3 -10 -2 atm was measured by a differential oil-pressure gauge, in the range 10 -2 -10 -1 atm by a differential mercury-pressure gauge, and in the range from 0.1 to 100 atm by a membrane manometer. The temperature of the specimens was measured to within +-1% by an optical pyrometer. The nitrogen and oxygen contents of ZrNsub(x) were determined by extraction gas chromatography to within 0.2 and 0.05 wt.% for nitrogen and oxygen, respectively. The dependence of the incongruent melting point of ZrNsub(x) on the equilibrium pressure of nitrogen in the range 10 -3 -60 atm was established. It was found that the pressure of oxygen as impurity in ZrNsub(x) greatly reduces its melting point

  10. Corrosion resistance of amorphous NiCrZr and NiCrMoZr alloys

    Naka, M.; Miyake, M.; Okamoto, I.

    1987-01-01

    One of the authors has reported that the corrosion resistance of chromium containing amorphous alloys is extremely improved by alloying phosphorus among metalloids. Two factors operate for the improvement of corrosion resistance of the amorphous alloys. First, phosphorus serves for the rapid formation of protective passive film. Second, the compositional and structural homogeneity in amorphous state also account for the formation of protective film. The latter factor has been clearly seen in the high corrosion resistance of CoCrMoZr and CoCrWZr alloys without metalloids. In order to clarify the separately two factors in the corrosion resistance of amorphous alloys, the corrosion resistance of amorphous alloys without metalloids has to be further investigated. This paper also deals with the corrosion resistance and electrochemical behavior of NiCrZr and NiCrMoZr alloys in 1N HCl, and compare them with the corrosion behavior of the crystalline alloys containing the same composition as that of the amorphous alloys

  11. Deuterium absorption and material phase characteristics of Zr2Fe

    Nobile, A.; Mosley, W.C.; Holder, J.S.; Brooks, K.N.

    1992-01-01

    Scanning electron microscope (SEM) images of polished surfaces, electron probe microanalysis, and X-ray powder diffractometry indicated the presence of a continuous Zr 2 Fe phase with secondary phases of ZrFe 2 , Zr 5 FeSn, α-Zr, and Zr 6 Fe 3 O. A statistically-designed experiment to determine the effects of temperature, time, and vacuum quality On activation of St 198 revealed that when activated at low temperature (350 degrees C) deuterium absorption rate was slower when the vacuum quality was pwr (2.5 Pa vs. 3x10 -4 Pa). However, at higher activation temperature (500 degrees C), deuterium absorption rate was fast and was independent of vacuum quality. Deuterium pressure-composition-temperature (P-C-T) data are reported for St 198 in the temperature range 200--500 degrees C. The P-C-T data over the full range of deuterium loading and at temperatures of 350 degrees C and below is described by: K 0e -(ΔH α /RT)=PD 2 q 2 /(q*-q) 2 where ΔHα and K 0 have values of 101.8 kJ·mole -1 and 3.24x10 -8 Pa -1 , and q* is 15.998 kPa·L -1 ·g -1 . At higher temperatures, one or more secondary reactions in the solid phase occur that slowly consume D 2 from the gas phase. XRD suggests these reactions to be: 2 Zr 2 FeD x → x ZrD 2 + x/3 ZrFe 2 + (2 - 2/3x) Zr 2 Fe and Zr 2 FeD x + (2 -1/2x) D 2 → ZrD 2 + Fe, where 0 < x < 3. Reaction between gas phase deuterium and Zr2FC formed in the first reaction accounts for the observed consumption of deuterium from the gas phase by this reaction

  12. Preparation and sintering of Zr(C,N,O) phases

    Tamborenea, S.; Mazzoni, A.D.; Aglietti, E.F.

    2003-01-01

    The Zr(C,O,N) compounds form a great mono-phase zone belonging to the pseudoternary ZrO-ZrN-ZrC system.Theses phases have cubic crystalline structure with a o parameter depending on the C, O 2 and N 2 content.These phases have many potential applications in the manufacture of ceramic pieces utilizable as electronic conductors.The Zr (C,O,N) phases can be obtained from ZrO 2 by carbonitriding reactions: that is carbothermal reduction and simultaneous nitriding.In this work a series of experiences of carbonitriding of zirconia under different conditions (temperatures between 1400 and 1600degC, times of 120 min, carbon content between 20 and 40%) in order to obtain suitable powders to be sintered.The XRD analysis shows the Zr(C,O,N) as the main products and β -ZrON as the only secondary product in proportions depending on the obtaining conditions.The variables employed were the C content and the reaction temperature.The Zr(C,O,N) content varies between 40 and 90% and tends to increase with the temperature and the carbon content whereas the β -ZrON phase varies between the 40 and 10 % decreasing its proportion with temperature and the carbon content.The oxidation resistance of these phases was studied by DTA-TG tests in air.Results show complete oxidation reaction at ∼500degC in air.The sintering of these materials was made on disks obtained by pressing of powders of Zr(C,N,O) contents higher than 90%.Sintering was performed in nitrogen atmosphere and temperatures between 1450 and 1620degC.Disks were characterized by pycnometry and Hg volumeter.The densities obtained were between 5 and 6,6g/cm 3 with a tendency to increase with the Zr(C,N,O) phase content, the temperature and the sintering time.Sintered disks were characterized by dilatometry in N 2

  13. Regularities of recrystallization in rolled Zr single crystals

    Isaenkova, M; Perlovich, Yu; Fesenko, V; Krymskaya, O; Krapivka, N; Thu, S S

    2015-01-01

    Experiments by rolled single crystals give a more visible conception of the operating mechanisms of plastic deformation and the following recrystallization, than experiments by polycrystals. Studies by usage of X-ray diffraction methods were conducted by Zr single crystals. It was revealed, that regions of the α-Zr matrix, deformed mainly by twinning, are characterized with decreased tendency to recrystallization. Orientations of recrystallized α-Zr grains correspond to “slopes” of maxima in the rolling texture, where the level of crystalline lattice distortion is maximal and the number of recrystallization nuclei is most of all. (paper)

  14. Ni-free Zr-Cu-Al-Nb-Pd bulk metallic glasses with different Zr/Cu ratios for biomedical applications.

    Huang, Lu; Yokoyama, Yoshihiko; Wu, Wei; Liaw, Peter K; Pang, Shujie; Inoue, Akihisa; Zhang, Tao; He, Wei

    2012-08-01

    Zr-based bulk metallic glasses (BMGs) possess attractive properties for prospective biomedical applications. The present study designs Ni-free Zr-Cu-Al-Nb-Pd BMGs and investigates their in vitro biocompatibility by studying mechanical properties, bio-corrosion resistance, and cellular responses. The Ti-6Al-4V alloy is used as a reference material. It is found that the Zr-based BMGs exhibit good mechanical properties, including high strengths above 1600 MPa, high hardness over 4700 MPa, and low elastic moduli of 85-90 GPa. The Zr-based BMGs are corrosion resistant in a simulated body environment, as revealed by wide passive regions, low passive current densities, and high pitting overpotentials. The formation of ZrO(2)-rich surface passive films of the Zr-based BMGs contributes to their high corrosion resistance, whereas their pitting corrosion in the phosphate buffered saline solution can be attributed to the sensitivity of the ZrO(2) films to the chloride ion. The general biosafety of the Zr-based BMGs is revealed by normal cell adhesions and cell morphologies. Moreover, the Zr/Cu content ratio in the alloy composition affects the biocompatibility of the Zr-based BMGs, by increasing their corrosion resistance and surface wettability with the increase of the Zr/Cu ratio. Effects of Zr/Cu ratios can be used to guide the future design of biocompatible Zr-based BMGs. Copyright © 2012 Wiley Periodicals, Inc.

  15. Constitutive equations for Zr1Nb. II

    Novak, J.

    1986-01-01

    Based on existing knowledge and constitutive equations for non-irradiated material, constitutive equations were written for Zr1Nb irradiated at 573 K at deformation in the direction of forming. Constitutive equations express the following material characteristics: dependence of shear strength on fast neutron fluence, superposition of deformation hardening and subsequent radiation hardening, the effect of stress on deformation rate, and for fluences above ca. 10 24 n.m -2 (E>1 MeV) the course of the deformation curve for various fluence levels. The values apply for temperatures and rates of deformation which are characteristic of transient processes during changes in the power output of fuel elements of pressurized water reactors. (J.B.)

  16. Softening during deformation of Zr alloys

    Kral, R.; Trojanova, Z.; Lukac, P.

    1994-01-01

    The strain hardening behaviour is described by the work hardening rate. The work hardening rate depends on the dislocation density changes which result from the competition between the rate of dislocation storage and the rate of annihilation of dislocations. In the present work the deformation behaviour of Zr-based alloys is investigated. From the stress-strain curves the work hardening rate is calculated and its stress dependence is studied at various temperatures between 300 and 1000 K. Experimental investigations show that at first the work hardening rate decreases quasi-linearly with increasing stress. After a certain stress is reached, the work hardening rate decreases more slowly with increasing stress. We discuss the influence of hardening and softening processes on the deformation behaviour. Analytical models are compared with experimental results. (orig.)

  17. On the anisotropy of in-reactor creep of Zr-2.5Nb tubes

    Causey, A.R.; Holt, R.A.

    1993-06-01

    Creep specimens made from cold-worked Zr-2.5Nb tubes, fabricated with two different microstructures and crystallographic textures, were irradiated in the Osiris reactor in France in a fast-neutron flux of about 1.8 x 10 18 n.m -2 .s -1 , E > MeV, at 553 and 585 K. The hoop stresses from internal Fluences, up to 4 x 10 25 n.m -2 , more than double those achieved an any other creep test on cold-worked Zr-2.5Nb in which both axial and transverse strain were measured. Creep rates were obtained from strain versus fluence plots, and creep compliances were obtained from plots of the strain rates against hoop stress for each material at each temperature. The ratio of creep rates at 583 K to those at 553 K was ∼ 1.36, a little higher than that extrapolated from stress relaxation results at temperatures between 523 and 568 K. The ratio of the biaxial creep compliance in the axial direction to that in the transverse directions is different for the two test materials: 0.0 to -0.1 for the fuel sheathing texture and 0.5 to 0.6 for the pressure tube texture. The results were analysed using a self-consistent model developed to account for the contributions to the creep anisotropy of the three microstructure parameters involved and to account for the grain interaction effects. The model, which was normalized to test reactor and power reactor creep data for cold-worked Zr-2.5Nb tubes, predicted the ratio of the creep compliancies to be -0.26 and 0.63, respectively. Thus the creep anisotropy of Zr-2.5Nb tubes with pressure-tube-like crystallographic texture can be adequately predicted. (author). 18 refs., 4 tabs., 13 figs

  18. Preparation, characterization and activity evaluation of CaZrTi2O7 photocatalyst

    Chen Shifu; Ji Mingsong; Yuang Yunguang; Liu Wei

    2012-01-01

    CaZrTi 2 O 7 photocatalyst sample was prepared by a polymerizable complex method. The photocatalyst was characterized by X-ray powder diffraction, scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence emission spectroscopy, Brunauer–Emmett–Teller analysis, N 2 adsorption measurements, and terephthalic acid probed fluorescence technique. The photocatalytic activity of the sample was evaluated by photocatalytic oxidation of methyl orange and photocatalytic reduction of Cr 2 O 7 2− and nitrobenzene. The results showed that when the reaction solution was illuminated by UV light for 50 min, the photooxidation efficiency of methyl orange and the photoreduction efficiency of Cr 2 O 7 2− were 83.1% and 87.9%, respectively. When methanol was used as the holes scavengers and the illumination time was 10 h in the photocatalytic reduction experiment of nitrobenzene, the production efficiency of aniline was 70.3%. The effect of the heat treatment conditions on the photocatalytic activity was also investigated. The optimum preparation condition for CaZrTi 2 O 7 sample is 800 °C for 12 h. The mechanisms of influence on the photocatalytic activity of the sample were also discussed with the valance band theory. - Highlights: ► CaZrTi 2 O 7 photocatalyst was prepared by a polymerizable complex method. ► The heat treatment has a significant influence on the photocatalytic activity. ► The optimal heat treatment condition is approximately 800 °C for 12 h. ► The CaZrTi 2 O 7 has the band bap of about 2.89 eV with particle size of about 80 nm.

  19. Effect of texture on creep deformation behavior of Zr-2.5Nb alloy

    Guguloth, Krishna; Swaminathan, J.; Mitra, Rahul; Ghosh, R.N.; Singh, R.N.; Chakravartty, J.K.

    2016-01-01

    Zr-2.5%Nb alloys are extensively used as high temperature pressure tubes in nuclear reactor. Therefore creep behavior of this alloy is of considerable importance. The paper presents creep strain-time plots on two sets of specimens made from two as received pressure tubes having different diameters. These tubes were reported to have undergone different processing routes; both tubes were autoclaved at the same temperature in the steam atmosphere. A comparison of the creep strain-time plots of the two sets of specimen under identical test conditions showed a marked difference. The chemical composition and the microstructure of the two sets of samples were also found to be similar. Therefore X-ray diffraction patterns were taken from the two tubes. The ratio of intensity of two prominent reflections from 0002 and 1120 planes of alpha Zr in the case of 90mm tube was found to be 1.79; whereas that from the 110mm tube was 0.25. This suggests that in the case of 110mm tube most of the basal planes were less favorably oriented with respect to the loading axis. This is the reason why creep strength of 110mm tube was found to be higher. The paper also describes how the effect of texture can be incorporated in evaluating the creep behavior of Zr-Nb alloy. This suggests that a relatively larger volume of creep test data on Zr-2.5Nb pressure tube is necessary to account for the effect texture so that a reliable estimate of its creep life could be obtained. (author)

  20. Nano ZrO{sub 2} particles in nanocrystalline Fe–14Cr–1.5Zr alloy powders

    Xu, W.Z.; Li, L.L.; Saber, M.; Koch, C.C.; Zhu, Y.T., E-mail: ytzhu@ncsu.edu; Scattergood, R.O.

    2014-09-15

    Here we report on the formation of nano ZrO{sub 2} particles in Fe–14Cr–1.5Zr alloy powders synthesized by mechanical alloying. The nano ZrO{sub 2} particles were found uniformly dispersed in the ferritic matrix powders with an average size of about 3.7 nm, which rendered the alloy powders so stable that it retained nanocrystalline structure after annealing at 900 °C for 1 h. The ZrO{sub 2} nanoparticles have a tetragonal crystal structure and the following orientation relationship with the matrix: (0 0 2){sub ZrO2}//(0 0 2){sub Matrix} and [0 1 0]{sub ZrO2}//[1 2 0]{sub Matrix}. The size and dispersion of the ZrO{sub 2} particles are comparable to those of Y–Ti–O enriched oxides reported in irradiation-resistant ODS alloys. This suggests a potential application of the new alloy powders for nuclear energy applications.

  1. Biological Properties of Ti-Nb-Zr-O Nanostructures Grown on Ti35Nb5Zr Alloy

    Zhaohui Li

    2012-01-01

    Full Text Available Surface modification of low modulus implant alloys with oxide nanostructures is one of the important ways to achieve favorable biological behaviors. In the present work, amorphous Ti-Nb-Zr-O nanostructures were grown on a peak-aged Ti35Nb5Zr alloy through anodization. Biological properties of the Ti-Nb-Zr-O nanostructures were investigated through in vitro bioactivity testings, stem cell interactions, and drug release experiments. The Ti-Nb-Zr-O nanostructures demonstrated a good capability of inducing apatite formation after immersion in simulated body fluids (SBFs. Drug delivery experiment based on gentamicin and the Ti-Nb-Zr-O nanostructures indicated that a high drug loading content could result in a prolonged release process and a higher quantity of drug residues in the oxide nanostructures after drug release. Quick stem cell adhesion and spreading, as well as fast formation of extracellular matrix materials on the surfaces of the Ti-Nb-Zr-O nanostructures, were found. These findings make it possible to further explore the biomedical applications of the Ti-Nb-Zr-O nanostructure modified alloys especially clinical operation of orthopaedics by utilizing the nanostructures-based drug-release system.

  2. Honour and respect in Danish prisons

    Laursen, Julie; Laws, Ben

    2017-01-01

    to create accountable and rational actors, who ‘self-manage’, the therapeutic ethos neglects participants’ life experiences and subcultural capital. Open expressions of moral values by prisoners (such as displays of honour and respect) are considered to be cognitive distortions which are dismissed......Using empirical data from prison-based cognitive-behavioural programmes, this article considers how prisoners’ subcultural capital shapes their responses to demands for ‘cognitive self-change’. We argue that accounts of ‘respect’ in the prior literature fail to capture how prisoners react...

  3. Wettability of zirconium diboride ceramics by Ag, Cu and their alloys with Zr

    Muolo, M.L.; Ferrera, E.; Novakovic, R.; Passerone, A.

    2003-01-01

    Sintered ZrB 2 ceramics, pure and with 4 wt.% Ni as sintering aid, have been tested in contact with liquid Ag, Cu, Ag-Cu and Ag-Cu-Zr. ''Pure'' ZrB 2 ceramics are wetted by Ag-Zr alloys, and ZrB 2 /Ni ceramics also by pure Cu. The wetting behaviour is briefly discussed in terms of existing wetting theories

  4. Synthesis of intermetallic hydrides of Zr-Ni system in the burning regime

    Akopyan, A.G.; Dolukhanyan, S.K.; Karapetyan, A.K.; Merzhanov, A.G.

    1983-06-01

    Conditions for production of intermetallides in the Zr-Ni system and their hydrides in the burning regime are studied. Burning regularities of Zr/sub 2/Ni and ZrNi intermetallides in hydrogen are studied, the burning mechanism is found. It is shown that burning proceeds at abnormally low temperatures. Optimum synthesis conditions for Zr/sub 2/NiH/sub 5/ and ZrNiH/sub 3/ hydrides are determined.

  5. A multi-component Zr alloy with comparable strength and Higher plasticity than Zr-based bulk metallic glasses

    Liang, S.X.; Yin, L.X.; Ma, M.Z.; Jing, R.; Yu, P.F.; Zhang, Y.F.; Wang, B.A.; Liu, R.P.

    2013-01-01

    Zirconium (Zr)-based bulk metallic glass possesses the highest potential as a structural material among metallic glasses. Although Zr-based bulk metallic glass exhibits extremely high strength, its potential application has been restricted by a number of issues, such as fragility, small size, difficult fabrication into different shapes and poisonous beryllium content, among others. In this paper, a Zr-based crystal alloy with comparable strength and higher plasticity than Zr-based bulk metallic glass is presented. The proposed Zr-based alloy has a tensile strength greater than 1600 MPa. That value is comparable to the 1500 MPa to 2000 MPa strength of Zr-based bulk metallic glasses (BMGs). The ductility in terms of elongation reached 6.2%; at the same time, the 1400 MPa tensile strength was retained. This phenomenon is not possible for Zr-based BMGs. XRD results show that the proposed ultrahigh-strength Zr-based crystal alloy has two-phase structures: an hcp-structured α phase and a bcc-structured β phase. The forged specimen exhibits a typical basket-weave microstructure, which is characterised by the interlaced plate α phase separated from the β phase matrix. Fine, short bar-shaped α phases precipitated along the original β grain boundary together with ultrafine dot-shaped α phases that presented inside the original β grain when the ageing temperature was between 500 °C and 525 °C. As the ageing temperature increased, the dot-shaped α phase grew into plate shapes, decreasing the material's strength and increasing its plasticity. The ultrafine dot-shaped and short bar-shaped α phases in the original β phase matrix are the main strengthening mechanisms of the ultrahigh-strength Zr-based crystal alloy.

  6. Respect distances. Rationale and means of computation

    Munier, Raymond [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Hoekmark, Harald [Clay Technology, Lund (Sweden)

    2004-12-01

    Canisters with spent nuclear fuel can obviously not be located within deformation zones as this might jeopardise their long term mechanical stability and thereby constitute a potential hazard to the biosphere. Less apparent, but equally important, is the fact that earthquakes trigger reactivation, slip, of structures some distance from their hypocentres due to, among many other factors, stress redistribution. Fault slip across a deposition hole might damage the isolation capacity of the canister and thereby jeopardise the overall integrity of the barrier system. Therefore, the following question might be posed: What is the distance from a deformation zone beyond which a canister can be safely emplaced? This respect distance cannot be readily computed because, unknown future events aside, there are some complicated aspects that need to be addressed e.g. degree of conservatism, scale, our ability to model ice sheets and earthquakes, etc. In this report we discuss various aspects of the assignment of respect distances, propose a methodology for its assignment and apply the methodology to the Forsmark Site as a worked example. Our main concern, in the context discussed in this report, is the post glacial faults anticipated to occur after the next glaciations. To properly address conservativeness, analysis of risk, and its implementation in safety analysis, we provide an extensive compilation of our current knowledge on post glacial faults as an appendix.

  7. Respect distances. Rationale and means of computation

    Munier, Raymond; Hoekmark, Harald

    2004-12-01

    Canisters with spent nuclear fuel can obviously not be located within deformation zones as this might jeopardise their long term mechanical stability and thereby constitute a potential hazard to the biosphere. Less apparent, but equally important, is the fact that earthquakes trigger reactivation, slip, of structures some distance from their hypocentres due to, among many other factors, stress redistribution. Fault slip across a deposition hole might damage the isolation capacity of the canister and thereby jeopardise the overall integrity of the barrier system. Therefore, the following question might be posed: What is the distance from a deformation zone beyond which a canister can be safely emplaced? This respect distance cannot be readily computed because, unknown future events aside, there are some complicated aspects that need to be addressed e.g. degree of conservatism, scale, our ability to model ice sheets and earthquakes, etc. In this report we discuss various aspects of the assignment of respect distances, propose a methodology for its assignment and apply the methodology to the Forsmark Site as a worked example. Our main concern, in the context discussed in this report, is the post glacial faults anticipated to occur after the next glaciations. To properly address conservativeness, analysis of risk, and its implementation in safety analysis, we provide an extensive compilation of our current knowledge on post glacial faults as an appendix

  8. Promoting respect at home and abroad

    2015-01-01

    This week, I’d like to focus on respect, whether at home, at work or on the international scene. Last week, I had the opportunity to visit the SESAME laboratory in Jordan along with the new European Commissioner for Research, Carlos Moedas. Since taking up his post, Mr Moedas has attached great importance to the role science can play in diplomacy, and the visit was on his initiative.   Through the EU-funded CESSAMag project, CERN is coordinating the provision of magnets and power supplies for the SESAME main ring. The first are currently being tested at CERN by a team involving accelerator scientists from the SESAME members, and all are due to be delivered to SESAME in time for commissioning in the second half of 2016. SESAME, and CERN’s contribution to the project, are well documented in the pages of the Bulletin, but what really impresses when you visit the lab is the diversity of people working there and the degree of mutual respect they show to each other. SESAME will...

  9. Revisiting Respect for Persons in Genomic Research

    Debra J. H. Mathews

    2014-01-01

    Full Text Available The risks and benefits of research using large databases of personal information are evolving in an era of ubiquitous, internet-based data exchange. In addition, information technology has facilitated a shift in the relationship between individuals and their personal data, enabling increased individual control over how (and how much personal data are used in research, and by whom. This shift in control has created new opportunities to engage members of the public as partners in the research enterprise on more equal and transparent terms. Here, we consider how some of the technological advances driving and paralleling developments in genomics can also be used to supplement the practice of informed consent with other strategies to ensure that the research process as a whole honors the notion of respect for persons upon which human research subjects protections are premised. Further, we suggest that technological advances can help the research enterprise achieve a more thoroughgoing respect for persons than was possible when current policies governing human subject research were developed. Questions remain about the best way to revise policy to accommodate these changes.

  10. Synthetic tactile perception induced by transcranial alternating-current stimulation can substitute for natural sensory stimulus in behaving rabbits.

    Márquez-Ruiz, Javier; Ammann, Claudia; Leal-Campanario, Rocío; Ruffini, Giulio; Gruart, Agnès; Delgado-García, José M

    2016-01-21

    The use of brain-derived signals for controlling external devices has long attracted the attention from neuroscientists and engineers during last decades. Although much effort has been dedicated to establishing effective brain-to-computer communication, computer-to-brain communication feedback for "closing the loop" is now becoming a major research theme. While intracortical microstimulation of the sensory cortex has already been successfully used for this purpose, its future application in humans partly relies on the use of non-invasive brain stimulation technologies. In the present study, we explore the potential use of transcranial alternating-current stimulation (tACS) for synthetic tactile perception in alert behaving animals. More specifically, we determined the effects of tACS on sensory local field potentials (LFPs) and motor output and tested its capability for inducing tactile perception using classical eyeblink conditioning in the behaving animal. We demonstrated that tACS of the primary somatosensory cortex vibrissa area could indeed substitute natural stimuli during training in the associative learning paradigm.

  11. Mechanically, the shoot apical meristem of Arabidopsis behaves like a shell inflated by a pressure of about 1 MPa

    Léna eBeauzamy

    2015-11-01

    Full Text Available In plants, the shoot apical meristem contains the stem cells and is responsible for the generation of all aerial organs. Mechanistically, organogenesis is associated with an auxin-dependent local softening of the epidermis. This has been proposed to be sufficient to trigger outgrowth, because the epidermis is thought to be under tension and stiffer than internal tissues in all the aerial part of the plant. However, this has not been directly demonstrated in the shoot apical meristem. Here we tested this hypothesis in Arabidopsis using indentation methods and modeling. We considered two possible scenarios: either the epidermis does not have unique properties and the meristem behaves as a homogeneous linearly-elastic tissue, or the epidermis is under tension and the meristem exhibits the response of a shell under pressure. Large indentation depths measurements with a large tip (~size of the meristem were consistent with a shell-like behavior. This also allowed us to deduce a value of turgor pressure, estimated at 0.82 ± 0.16 MPa. Indentation with atomic force microscopy provided local measurements of pressure in the epidermis, further confirming the values obtained from large deformations. Altogether, our data demonstrate that the Arabidopsis shoot apical meristem behaves like a shell under a MPa range pressure and support a key role for the epidermis in shaping the shoot apex.

  12. Chronic monitoring of cortical hemodynamics in behaving, freely-moving rats using a miniaturized head-mounted optical microscope

    Sigal, Iliya; Gad, Raanan; Koletar, Margaret; Ringuette, Dene; Stefanovic, Bojana; Levi, Ofer

    2016-03-01

    Growing interest within the neurophysiology community in assessing healthy and pathological brain activity in animals that are awake and freely-behaving has triggered the need for optical systems that are suitable for such longitudinal studies. In this work we report label-free multi-modal imaging of cortical hemodynamics in the somatosensory cortex of awake, freely-behaving rats, using a novel head-mounted miniature optical microscope. The microscope employs vertical cavity surface emitting lasers (VCSELs) at three distinct wavelengths (680 nm, 795 nm, and 850 nm) to provide measurements of four hemodynamic markers: blood flow speeds, HbO, HbR, and total Hb concentration, across a > 2 mm field of view. Blood flow speeds are extracted using Laser Speckle Contrast Imaging (LSCI), while oxygenation measurements are performed using Intrinsic Optical Signal Imaging (IOSI). Longitudinal measurements on the same animal are made possible over the course of > 6 weeks using a chronic window that is surgically implanted into the skull. We use the device to examine changes in blood flow and blood oxygenation in superficial cortical blood vessels and tissue in response to drug-induced absence-like seizures, correlating motor behavior with changes in blood flow and blood oxygenation in the brain.

  13. On the (1 + 3) threading of spacetime with respect to an arbitrary timelike vector field

    Bejancu, Aurel [Kuwait University, Department of Mathematics, P.O.Box 5969, Safat (Kuwait); Calin, Constantin [Technical University ' ' Gh.Asachi' ' , Department of Mathematics, Iasi (Romania)

    2015-04-15

    We develop a newapproach on the (1 + 3) threading of spacetime (M, g) with respect to a congruence of curves defined by an arbitrary timelike vector field. The study is based on spatial tensor fields and on theRiemannian spatial connection ∇*, which behave as 3D geometric objects. We obtain new formulas for local components of the Ricci tensor field of (M, g) with respect to the threading frame field, in terms of the Ricci tensor field of ∇* and of kinematic quantities. Also, new expressions for time covariant derivatives of kinematic quantities are stated. In particular, a new form of Raychaudhuri's equation enables us to prove Lemma 6.3, which completes a well-known lemma used in the proof of the Penrose-Hawking singularity theorems. Finally, we apply the new (1 + 3) formalism to the study of the dynamics of a Kerr-Newman black hole. (orig.)

  14. Microstructural investigation of as-cast uranium rich U–Zr alloys

    Zhang, Yuting, E-mail: zhangyuting@caep.cn [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); School of Nuclear Science and Technology, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China); Wang, Xin [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Zeng, Gang [Institute of Materials, China Academy of Engineering Physics, Jiangyou 621908, Sichuan (China); Wang, Hui [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China); Jia, Jianping [Institute of Materials, China Academy of Engineering Physics, Jiangyou 621908, Sichuan (China); Sheng, Liusi [School of Nuclear Science and Technology, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui (China); Zhang, Pengcheng, E-mail: zpc113@sohu.com [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621908, Sichuan (China)

    2016-04-01

    The present study evaluates the microstructure in as-cast uranium rich U–Zr alloys, an important subsystem of U–Pu–Zr ternary metallic nuclear reactor fuel, as a function of the Zr content, from 2wt.% to 15wt.%Zr. It has been previously suggested that the unique intermetallic compound δ phase in U–Zr alloys is only present in as-cast U–Zr alloys with a Zr content exceeding 10wt.%Zr. However, our analysis of transmission electron microscopy (TEM) data shows that the δ phase is common to all as-cast alloys studied in this work. Furthermore, specific coherent orientation relationship is found between the α and δ phases, consistent with previous findings, and a third variant is discovered in this paper. - Highlights: • Initially, lattice parameter of as-cast U–Zr alloys decrease with the increasing Zr content, and then increase. • XRD data show the presence of δ-UZr{sub 2} phase in as-cast U–Zr alloys with a Zr content of more than 8wt.% Zr. • Finding δ-UZr{sub 2} phase exists in all as-cast uranium rich U–Zr alloys, even for alloys with a lean Zr content. • Three kinds of preferential orientations of the δ phase grow.

  15. Comet LINEAR C/1999 S4 - an absolutely well-behaved comet before breakup

    Peschke, S. B.; Lisse, C. M.; Fernandez, Y. R.; Ressler, M.; Stickel, M.; Kaminski, C.; Golish, B.

    2000-10-01

    We present results from infrared imaging of comet LINEAR C/1999 S4 on June 17 - 19, 2000 (pre-breakup), using the near-IR camera NSFCAM and the mid-IR camera MIRLIN at the 3m NASA/IRTF. Images and multi-wavelength spectroscopy were obtained in the zJHK'L'MNQ bands, and were used to create a 1.0 - 25 μ m SED of the comet's dust and nucleus. The coma's contribution at each wavelength was modeled using spatial fitting (Fernandez 1999, PhD thesis; Lisse et al. 1999, Icarus 140, 189). The resulting comatic and nuclear SEDs were then modeled using modified Mie theory (Lisse et al. 1998, ApJ 496, 971) and the standard nuclear thermal models (Lebofsky and Spencer 1989, Asteroids II, 128), respectively. We report the resulting dust PSD, mass loss rate, and albedo, as well as the nuclear radius, and we compare these results to those obtained by others from optical data both before and after the comet's breakup in late July 2000.

  16. When fellow customers behave badly: Witness reactions to employee mistreatment by customers.

    Hershcovis, M Sandy; Bhatnagar, Namita

    2017-11-01

    In 3 experiments, we examined how customers react after witnessing a fellow customer mistreat an employee. Drawing on the deontic model of justice, we argue that customer mistreatment of employees leads witnesses (i.e., other customers) to leave larger tips, engage in supportive employee-directed behaviors, and evaluate employees more positively (Studies 1 and 2). We also theorize that witnesses develop less positive treatment intentions and more negative retaliatory intentions toward perpetrators, with anger and empathy acting as parallel mediators of our perpetrator- and target-directed outcomes, respectively. In Study 1, we conducted a field experiment that examined real customers' target-directed reactions to witnessed mistreatment in the context of a fast-food restaurant. In Study 2, we replicated Study 1 findings in an online vignette experiment, and extended it by examining more severe mistreatment and perpetrator-directed responses. In Study 3, we demonstrated that employees who respond to mistreatment uncivilly are significantly less likely to receive the positive outcomes found in Studies 1 and 2 than those who respond neutrally. We discuss the implications of our findings for theory and practice. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Arsenic and fluoride removal from contaminated drinking water with Haix-Fe-Zr and Haix-Zr resin beads.

    Phillips, Debra H; Sen Gupta, Bhaskar; Mukhopadhyay, Soumyadeep; Sen Gupta, Arup K

    2018-06-01

    The objective of the study was to carry-out batch tests to examine the effectiveness of Haix-Fe-Zr and Haix-Zr resin beads in the removal of As(III), As(V) and F - from groundwater with a similar geochemistry to a site where a community-based drinking water plant has been installed in West Bengal, India. The groundwater was spiked separately with ∼200 μg/L As(III) and As(V) and 5 mg/L F - . Haix-Zr resin beads were more effective than Haix-Fe-Zr resin beads in removing As(III) and As(V). Haix-Zr resin beads showed higher removal of As(V) compared to As(III). Haix-Zr resin beads removed As(V) below the WHO (10 μg/L) drinking water standards at 8.79 μg/L after 4 h of shaking, while As(III) was reduced to 7.72 μg/L after 8 h of shaking. Haix-Fe-Zr resin beads were more effective in removing F - from the spiked groundwater compared to Haix-Zr resin beads. Concentrations of F - decreased from 6.27 mg/L to 1.26 mg/L, which is below the WHO drinking water standards (1.5 mg/L) for F - , after 15 min of shaking with Haix-Fe-Zr resin beads. After 20 min of shaking in groundwater treated with Haix-Zr resin beads, F - concentrations decreased from 6.27 mg/L to 1.43 mg/L. In the removal of As(III), As(V), and F - from the groundwater, Haix-Fe-Zr and Haix-Zr resin beads fit the parabolic diffusion equation (PDE) suggesting that adsorption of these contaminants was consistent with inter-particle diffusion. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Effect of ZrB{sub 2} particles on the microstructure and mechanical properties of hybrid (ZrB{sub 2} + Al{sub 3}Zr)/AA5052 insitu composites

    Gautam, Gaurav, E-mail: gauravgautamm1988@gmail.com; Mohan, Anita, E-mail: amohan.app@iitbhu.ac.in

    2015-11-15

    Present study outlines the effect of ZrB{sub 2} particles variation on the morphology and mechanical properties of (ZrB{sub 2}+Al{sub 3}Zr)/AA5052Al alloy composites. Composites with varying amount of ZrB{sub 2} particles have been produced by direct melt reaction (DMR) technique. These composites have been characterized by X-ray diffractometer (XRD) and energy-dispersive spectroscopy (EDS) to confirm the presence of ZrB{sub 2} and Al{sub 3}Zr particles. Optical microscopy (OM) and scanning-electron microscopy (SEM) have been used to understand the morphology. To see the effect of ZrB{sub 2} variation on mechanical properties, hardness and tensile properties have been evaluated. The XRD and EDS results confirm the successful formation of ZrB{sub 2} particles in matrix of AA5052Al alloy. SEM and TEM studies exhibit that ZrB{sub 2} particles are mostly in hexagonal and some rectangular shape while Al{sub 3}Zr particles are in polyhedron and rectangular shapes. Most of ZrB{sub 2} particles are within a size range of 10–190 nm. Interface region is free of any impurity. OM studies show grain refinement of AA5052Al alloy matrix with formation of second phase ZrB{sub 2} particles. Tensile results indicate that the UTS and YS improve up to 3 vol.% of ZrB{sub 2} but beyond this composition a decreasing trend is observed. The strength coefficient increases with increase in ZrB{sub 2} particles up to 3 vol.% in the Al{sub 3}Zr/Al alloy composites, whereas strain hardening decreases. While beyond 3 vol.% ZrB{sub 2} particles in the Al{sub 3}Zr/Al alloy composite, opposite trend is observed in strength coefficient and strain hardening. Percentage elongation also improves with 1vol.% ZrB{sub 2}, but further addition of ZrB{sub 2} shows an adverse effect. However, a continuous increasing trend has been observed in bulk hardness. Fracture studies show facets of Al{sub 3}Zr particles and dimples of matrix, but with inclusion of ZrB{sub 2} dimple size decreases. Increase in Zr

  19. Evidence of icosahedral short-range order in Zr70Cu30 and Zr70Cu29Pd1 metallic glasses

    Saksl, K.; Franz, H.; Jovari, P.

    2003-01-01

    Change in local atomic environment during crystallization of Zr-based glassy alloys was studied by extended x-ray absorption fine structure (EXAFS) spectroscopy. The formation of icosahedral quasicrystalline phase followed by crystallization of tetragonal CuZr2 has been observed in the Zr70Cu29Pd1...... glassy alloy during annealing up to 850 K. On the other hand, the binary Zr70Cu30 alloy shows a single glassy to crystalline CuZr2 phase transformation. The local atomic environment of as-quenched Zr70Cu30 alloy is matched to an icosahedral local atomic configuration, which is similar to that of the as......-quenched Zr70Cu29Pd1 alloy and the alloy annealed at 593 K containing icosahedral phase. Considering that the supercooled liquid region appears prior to crystallization in the Zr70Cu30 glassy alloy, the observed results support the theory claiming a strong correlation between the existence of local...

  20. Friction Anisotropy with Respect to Topographic Orientation

    Yu, Chengjiao; Wang, Q. Jane

    2012-01-01

    Friction characteristics with respect to surface topographic orientation were investigated using surfaces of different materials and fabricated with grooves of different scales. Scratching friction tests were conducted using a nano-indentation-scratching system with the tip motion parallel or perpendicular to the groove orientation. Similar friction anisotropy trends were observed for all the surfaces studied, which are (1) under a light load and for surfaces with narrow grooves, the tip motion parallel to the grooves offers higher friction coefficients than does that perpendicular to them, (2) otherwise, equal or lower friction coefficients are found under this motion. The influences of groove size relative to the diameter of the mating tip (as a representative asperity), surface contact stiffness, contact area, and the characteristic stiction length are discussed. The appearance of this friction anisotropy is independent of material; however, the boundary and the point of trend transition depend on material properties. PMID:23248751

  1. Manger hors norme, respecter les normes

    Régnier, Faustine

    2007-01-01

    Fondée sur un corpus de près de 10 000 recettes de cuisine de la presse féminine française et allemande (1930‑2000), cette contribution met en évidence la façon dont l’exotisme permet de manger hors norme tout en restant dans les normes. Les pratiques culinaires étrangères ne peuvent être adoptées qu’au terme d’un travail de normalisation. Elles sont modifiées de manière à ce que soient respectées les normes du pays d’accueil, par là même mises en œuvre. Elles sont donc conçues comme un ensem...

  2. Discovery of ferromagnetism with large magnetic anisotropy in ZrMnP and HfMnP

    Lamichhane, Tej N.; Taufour, Valentin; Kaluarachchi, Udhara S.; Bud' ko, Sergey L.; Canfield, Paul C. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); The Ames Laboratory, US Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Masters, Morgan W. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Parker, David S. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Thimmaiah, Srinivasa [The Ames Laboratory, US Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)

    2016-08-29

    ZrMnP and HfMnP single crystals are grown by a self-flux growth technique, and structural as well as temperature dependent magnetic and transport properties are studied. Both compounds have an orthorhombic crystal structure. ZrMnP and HfMnP are ferromagnetic with Curie temperatures around 370 K and 320 K, respectively. The spontaneous magnetizations of ZrMnP and HfMnP are determined to be 1.9 μ{sub B}/f.u. and 2.1 μ{sub B}/f.u., respectively, at 50 K. The magnetocaloric effect of ZrMnP in terms of entropy change (ΔS) is estimated to be −6.7 kJ m{sup −3} K{sup −1} around 369 K. The easy axis of magnetization is [100] for both compounds, with a small anisotropy relative to the [010] axis. At 50 K, the anisotropy field along the [001] axis is ∼4.6 T for ZrMnP and ∼10 T for HfMnP. Such large magnetic anisotropy is remarkable considering the absence of rare-earth elements in these compounds. The first principle calculation correctly predicts the magnetization and hard axis orientation for both compounds, and predicts the experimental HfMnP anisotropy field within 25%. More importantly, our calculations suggest that the large magnetic anisotropy comes primarily from the Mn atoms, suggesting that similarly large anisotropies may be found in other 3d transition metal compounds.

  3. Discovery of ferromagnetism with large magnetic anisotropy in ZrMnP and HfMnP

    Lamichhane, Tej N.; Taufour, Valentin; Kaluarachchi, Udhara S.; Bud'ko, Sergey L.; Canfield, Paul C.; Masters, Morgan W.; Parker, David S.; Thimmaiah, Srinivasa

    2016-01-01

    ZrMnP and HfMnP single crystals are grown by a self-flux growth technique, and structural as well as temperature dependent magnetic and transport properties are studied. Both compounds have an orthorhombic crystal structure. ZrMnP and HfMnP are ferromagnetic with Curie temperatures around 370 K and 320 K, respectively. The spontaneous magnetizations of ZrMnP and HfMnP are determined to be 1.9 μ_B/f.u. and 2.1 μ_B/f.u., respectively, at 50 K. The magnetocaloric effect of ZrMnP in terms of entropy change (ΔS) is estimated to be −6.7 kJ m"−"3 K"−"1 around 369 K. The easy axis of magnetization is [100] for both compounds, with a small anisotropy relative to the [010] axis. At 50 K, the anisotropy field along the [001] axis is ∼4.6 T for ZrMnP and ∼10 T for HfMnP. Such large magnetic anisotropy is remarkable considering the absence of rare-earth elements in these compounds. The first principle calculation correctly predicts the magnetization and hard axis orientation for both compounds, and predicts the experimental HfMnP anisotropy field within 25%. More importantly, our calculations suggest that the large magnetic anisotropy comes primarily from the Mn atoms, suggesting that similarly large anisotropies may be found in other 3d transition metal compounds.

  4. Improvement of mechanical properties and corrosion resistance of biodegradable Mg-Nd-Zn-Zr alloys by double extrusion

    Zhang, Xiaobo, E-mail: xbxbzhang2003@163.com [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Wang, Zhangzhong [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Yuan, Guangyin [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, 200240 (China); Xue, Yajun [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Microstructure of Mg-Nd-Zn-Zr alloys was refined and homogenized by double extrusion process. Black-Right-Pointing-Pointer The mechanical properties of the alloys were significantly enhanced by double extrusion. Black-Right-Pointing-Pointer The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg-Nd-Zn-Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg-2.25Nd-0.11Zn-0.43Zr and Mg-2.70Nd-0.20Zn-0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg-Nd-Zn-Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  5. Improvement of mechanical properties and corrosion resistance of biodegradable Mg–Nd–Zn–Zr alloys by double extrusion

    Zhang, Xiaobo; Wang, Zhangzhong; Yuan, Guangyin; Xue, Yajun

    2012-01-01

    Highlights: ► Microstructure of Mg–Nd–Zn–Zr alloys was refined and homogenized by double extrusion process. ► The mechanical properties of the alloys were significantly enhanced by double extrusion. ► The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg–Nd–Zn–Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg–2.25Nd–0.11Zn–0.43Zr and Mg–2.70Nd–0.20Zn–0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg–Nd–Zn–Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  6. Crystallization behavior of ZrO{sub 2}−3Y{sub 2}O{sub 3}−xSrO precursor powders synthesized by a coprecipitation process

    Chu, Hsueh-Liang [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta- Hsueh Road, Tainan 70101, Taiwan (China); Hwang, Weng-Sing [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta- Hsueh Road, Tainan 70101, Taiwan (China); Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 1 Ta- Hsueh Road, Tainan 70101, Taiwan (China); Du, Je-Kang [Department of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Department of Dentistry, Kaohsiung Medical University, Chung Ho Memorial Hospital, 100 Tzyou 1st Road, Kaohsiung 80708, Taiwan (China); Chen, Ker-Kong, E-mail: enamel@kmu.edu.tw [Department of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Department of Dentistry, Kaohsiung Medical University, Chung Ho Memorial Hospital, 100 Tzyou 1st Road, Kaohsiung 80708, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China)

    2016-09-05

    Crystallization behaviors of ZrO{sub 2}−3Y{sub 2}O{sub 3}−xSrO precursor powders were studied with zirconium nitrate (Zr(NO{sub 3}){sub 4}·xH{sub 2}O), yttrium nitrate (Y(NO{sub 3}){sub 3}·6H{sub 2}O) and strontium nitrate (Sr(NO{sub 3}){sub 2}) constituting the initial materials. Differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), nano beam electron diffraction (NBED) and high-resolution TEM (HRTEM) were utilized to characterize the crystallization behavior of ZrO{sub 2}−3Y{sub 2}O{sub 3}−xSrO precursor powders. The activation energies of tetragonal ZrO{sub 2} (t-ZrO{sub 2}) crystallization were 389.1, 327.6, and 315.1 kJ/mol with SrO content for 1, 2, and 3 mol%, respectively, obtained with a non-isothermal method. The growth morphology parameter and growth mechanism index were close to 2.0 and 1.0, respectively, showing that t-ZrO{sub 2} had a plate-like morphology. - Highlights: • The single phase of tetragonal ZrO{sub 2} formed when calcined at 923 K for 2 h. • ZrO{sub 2}−3Y{sub 2}O{sub 3}−2SrO precursor powders crystallization is at 765.6 K. • The activation energy of t-ZrO{sub 2} crystallization was 389.1 kJ/mol with 1 mol% SrO. • The growth morphology and index of crystallization were close to 2.0 and 1.0.

  7. Fabrication of 94Zr thin target for RDM lifetime measurement

    Gupta, Chandan Kumar; Rohilla, Aman; Chamoli, S.K.; Abhilash, S.R.; Kabiraj, D.; Singh, R.P.; Mehta, D.

    2013-01-01

    The aim of the activity was to make a thin target of isotopically enriched 94 Zr for lifetime measurement experiment to be done with the plunger setup at the Inter University Accelerator Center (IUAC) Delhi

  8. Displacement energies for Zr measured in a HVEM

    Griffiths, M.

    1989-01-01

    This paper describes direct measurements of threshold displacement energies for Zr obtained by electron irradiation in a high voltage microscope (HVEM) and compares the measurements with the earlier data.

  9. First measurements of LIBS in the Zr-Nb system

    Previtali, E; Ararat, C; Corvalan, C; Iribarren, M

    2012-01-01

    The Zr-based alloys are used in the nuclear industry. Particularly these alloys are used for the nuclear fuel elements in PWR reactors and CANDU type reactors. For this last case, zirconium-niobium (Zr-Nb) alloys have a particular importance for its special features like: resistance to corrosion, appropriate mechanic features and a low capture effective cross section for thermal neutrons. In this work the first LIBS measurements on Zr-Nb samples are shown. The spectrums from the plasma emission for Zr-Nb alloys are studied and discussed. Particularly, the variation of intensities as a function of laser energy is presented. Finally, the ablation morphology and the depth of the crater ablation are studied

  10. Cold fusion in symmetric 90Zr induced reactions

    Keller, J.G.; Schmidt, K.H.; Hessberger, F.P.; Muenzenberg, G.; Reisdorf, W.; Clerc, H.G.; Sahm, C.C.

    1985-08-01

    Excitation functions for evaporation residues were measured for the reactions 90 Zr+ 89 Y, 90 Zr, 92 Zr, 96 Zr, and 94 Mo. Deexcitation only by γ radiation was found for the compound nuclei 179 Au, 180 Hg, 182 Hg, and 184 Pb. The cross sections for this process were found to be considerably larger than predicted by a statistical-model calculation using standard parameters for the γ-strength function. Fusion probabilities as well as fusion-barrier distributions were deduced from the measured cross sections. There are strong nuclear structure effects in subbarrier fusion. For energies far below the fusion barrier the increase of the fusion probabilities with increasing energy is found to be much steeper than predicted by WKB calculations. As a by-product of this work new α-spectroscopic information could be obtained for neutron deficient isotopes between Ir and Pb. (orig.)

  11. Spontaneous nano-clustering of ZrO2 in atomic layer deposited LayZr1-yOx thin films: Part 1 - Material characterization

    Klootwijk, J.H.; Jinesh, K.B.; Wolters, R.A.M.; Roozeboom, F.; Besling, W.

    2008-01-01

    During atomic layer deposition (ALD) of uniform LayZr1-yOx thin films, spontaneous segregation of ZrO2 nanocrystals takes place that are embedded in an amorphous La2O3 matrix. This occurs if the Zr content in the LayZr1-yOx film is above 30% i.e. if the pulse ratio between the lanthanum precursor

  12. Fully aligned high-spin states in 86Zr

    Doring, J.; Hohns, G.D.; Sylvan, G.N.

    1995-01-01

    To study multi-quasiparticle excitations and their interplay with collective degrees of freedom at very high spins, a new in-beam investigation of the even-even 86 Zr has been performed via the 58 Ni( 32 S,4p) reaction at 135 MeV using the early implementation of GAMMASPHERE combined with the 47π charged particle detector system MICROBALL. The yrast positive- and negative-parity sequences have been extended up to 30 + and 27 - levels, respectively. Calculations within the configuration-dependent shell-correction method using a cranked Nilsson potential have shown that the highest spins are built from the six g 9 /2 neutrons and at most four protons excited from the p 1/2 , p 3/2 , f 5/2 subshells to the g 9 /2 subshell at a small deformation. The 30 + and 27 - states are the highest possible fully-aligned states based on holes in the N = 3 shell. Higher spins can be built by promotion of one neutron from the g 9 /2 to the g 7 /2 subshell but with a quite high energy cost

  13. Óxidos Mistos de Al2O3/ZrO2 como Inibidores de Corrosão do Aço SAE 1020

    Marcelo Rodrigues da Silva

    2014-01-01

    Full Text Available This paper describes the use of Al2O3/ZrO2 mixed oxides synthesized by sol-gel process with different amounts of ZrO2 (5%, 10%, 15% and 20% by mass in the Al2O3 matrix and different temperatures of calcination, such as interesting inhibitor materials of corrosive processes of SAE 1020 steel. The materials were characterized by Infrared Spectroscopy Fourier Transform (FTIR and X-Ray Diffraction (XRD techniques. FTIR spectra show the typical Al-O and Zr-O bonds vibrations in the mixed oxides. The XRD patterns of the samples calcined at 800 °C and 1000 °C shows the ZrO2 tetragonal and γ-Al2O3 face-centered cubic (FCC phases. The corrosion tests showed that the SAE 1020 steel covered with mixed oxides have an anodic passive region, thereby inhibiting the corrosive processes on the metal surface. Furthermore, the found values for steel coated with mixed oxide synthesized indicate a decrease in corrosion potentials (Ecor and corrosion current (icor. With respect to different samples of mixed oxides, the sample with 20 % of ZrO2 in the Al2O3 matrix proved to be the best inhibitor of steel corrosion, with the lowest values of corrosion potential and corrosion current, - 1.32 V and 0.31 μA cm-2, respectively.

  14. The comparison of photocatalytic activity of synthesized TiO2 and ZrO2 nanosize onto wool fibers

    Moafi, Hadi Fallah; Shojaie, Abdollah Fallah; Zanjanchi, Mohammad Ali

    2010-01-01

    TiO 2 and ZrO 2 nanocrystals were successfully synthesized and deposited onto wool fibers using the sol-gel technique at low temperature. The photocatalytic activities of TiO 2 -coated and ZrO 2 -coated wool fibers were measured by studying photodegradation of methylene blue and eosin yellowish dyes. The initial and the treated samples were characterized by several techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction. The TEM study shows dispersed particles with 10-30 nm in size for TiO 2 -coated and 20-40 nm in size for ZrO 2 -coated samples on the fiber surface. Comparison of the photocatalytic activity of the coated samples reveals superiority of TiO 2 modified sample with respect to that of ZrO 2 for degradation of both dyes. Our observations indicate that by applying this technique to the fabrics, self-cleaning materials could be designed for practical application.

  15. Phase Stability in the Mo-Ti-Zr-C System via Thermodynamic Modeling and Diffusion Multiple Validation

    Kar, Sujoy Kumar; Dheeradhada, Voramon S.; Lipkin, Don M.

    2013-08-01

    Alloys in the Mo-rich corner of the Mo-Ti-Zr-C system have found broad applications in non-oxidizing environments requiring structural integrity well beyond 1273 K (1000 °C). Alloys such as TZM (Mo-0.5Ti-0.08Zr-0.03C by weight %) and TZC (Mo-1.2Ti-0.3Zr-0.1C by weight) owe much of their high temperature strength and microstructural stability to MC and M2C carbide phases. In turn, the stability of the respective carbides and the subsequent mechanical behavior of the alloys are strongly dependent on the alloying additions and thermal history. A CALPHAD-based thermodynamic modeling approach is employed to develop a quaternary thermodynamic database for the Mo-Ti-Zr-C system. The thermodynamic database thus developed is validated with diffusion multiple experiments and the validated database is exercised to elucidate the effects of alloying and thermal history on the phase equilibrium in Mo-rich alloys.

  16. Improving precursor adsorption characteristics in ATR-FTIR spectroscopy with a ZrO{sub 2} nanoparticle coating

    Park, Jaeseo [Korea Research Institute of Standards and Science, Center for Vacuum Technology (Korea, Republic of); Mun, Jihun [University of Science and Technology, Department of Advanced Device Technology (Korea, Republic of); Shin, Jae-Soo; Kim, Jongho; Park, Hee Jung [Daejeon University, Department of Advanced Materials Engineering (Korea, Republic of); Kang, Sang-Woo, E-mail: swkang@kriss.re.kr [Korea Research Institute of Standards and Science, Center for Vacuum Technology (Korea, Republic of)

    2017-02-15

    Nanoparticles were applied to a crystal surface to increase its precursor adsorption efficiency in an attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometer. Nanoparticles with varying dispersion stabilities were employed and the resulting precursor adsorption characteristics were assessed. The size of the nanoparticles was <100 nm (TEM). In order to vary the dispersion stability, ZrO{sub 2} nanoparticles were dispersed in aqueous solutions of different pH. The ZrO{sub 2} dispersion solutions were analyzed using scanning electron microscopy (SEM) while particle distribution measurements were analyzed using electrophoretic light scattering (ELS) and dynamic light scattering (DLS) techniques. ZrO{sub 2} nanoparticles dispersed in solutions of pH 3 and 11 exhibited the most stable zeta potentials (≥+30 or ≤−30 mV); these observations were confirmed by SEM analysis and particle distribution measurements. Hexamethyldisilazane (HMDS) was used as a precursor for ATR-FTIR spectroscopy. Consequently, when ZrO{sub 2} nanoparticle solutions with the best dispersion stabilities (pH 3 and 11) were applied to the adsorption crystal surface, the measurement efficiency of ATR-FTIR spectroscopy improved by ∼200 and 300%, respectively.

  17. Experimental Investigation on Ductile Mode Micro-Milling of ZrO2 Ceramics with Diamond-Coated End Mills

    Rong Bian

    2018-03-01

    Full Text Available ZrO2 ceramics are currently used in a broad range of industrial applications. However, the machining of post-sintered ZrO2 ceramic is a difficult task, due to its high hardness and brittleness. In this study, micro-milling of ZrO2 with two kinds of diamond-coated end mills has been conducted on a Kern MMP 2522 micro-milling center (Kern Microtechnik GmbH, Eschenlohe, Germany. To achieve a ductile mode machining of ZrO2, the feed per tooth and depth of cut was set in the range of a few micrometers. Cutting force and machined surface roughness have been measured by a Kistler MiniDynamometer (Kistler Group, Winterthur, Switzerland and a Talysurf 120 L profilometer (Taylor Hobson Ltd., Leicester, UK, respectively. Machined surface topography and tool wear have been examined under SEM. Experiment results show that the material can be removed in ductile mode, and mirror quality surface with Ra low as 0.02 μm can be achieved. Curled and smooth chips have been collected and observed. The axial cutting force Fz is always bigger than Fx and Fy, and presents a rising trend with increasing of milling length. Tool wear includes delamination of diamond coating and wear of tungsten carbide substrate. Without the protection of diamond coating, the tungsten carbide substrate was worn out quickly, resulting a change of tool tip geometry.

  18. Electric transport properties of the pentatelluride materials HfTe{sub 5} and ZrTe{sub 5}

    Tritt, T M; Wilson, M L; Littleton, R L [and others

    1997-07-01

    The authors have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe{sub 5} and ZrTe{sub 5}. They have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, T{sub p} where T{sub p} {approx} 80K for HfTe{sub 5} and T{sub p} {approx} 145K for ZrTe{sub 5}. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. These data are similar to behavior observed previously in these materials. They have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe{sub 5} and ZrTe{sub 5}. They have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 {micro}V/K and +65 {micro}V/K for HfTe{sub 5} and ZrTe{sub 5}, respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 {micro}V/K for HfTe{sub 5} and +35 {micro}V/K for ZrTe{sub 5}. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T {approx} 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 m{Omega}-cm and 24 m{Omega}-cm for HfTe{sub 5} and ZrTe{sub 5} respectively, compared to single crystal values of 0.35 m{Omega}-cm (HfTe{sub 5}) and 1.0 m{Omega}-cm (ZrTe{sub 5}). The authors have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. They will discuss these materials in relation to their potential as

  19. Obtaining and characterizing the binary compound Zr3Pt

    Tanoni, Diego; Arico, Sergio F; Alonso, Paula R

    2006-01-01

    The equilibrium phases in the Zr - Pt binary system are not fully defined. Experiences carried out from 0% to 50% at. Pt in the equilibrium diagram of Zr-Pt phases in 2001 revealed the presence of the intermetallic compounds Zr 2 Pt, Zr 5 Pt 3 , ZrPt (already previously identified by other authors) and a compound of 25% composition at Pt with an unidentified crystalline structure. This experimental work aims to fill out the information on this compound by characterizing its crystallography. An alloy was produced in the binary system Zr-Pt with a composition close to the stoichiometry by casting in an arc furnace, and was studied by optic and electronic metallography. The identification and crystallographic characterization of the phase is based on measurements of composition in electronic microwave and on analysis of spectrums obtained by X-ray diffraction. The results are presented, showing the presence in the cast structure of the solid solution zircon phases (hexagonal) and of the inter-metallic compound Zr 5 Pt 3 . These two phases were identified in the X-ray diffraction diagrams as well as the presence of other reflections that are associated with the inter-metallic Zr 3 Pt. The measurements of composition consistently reveal the presence of a phase of 25%at Pt composition. The structure's morphology shown in metallographies reveals the occurrence of a eutectic type transformation during cooling. We conclude that the formation of the phase sought in a composition 25 % at Pt should occur at temperatures below the eutectic transformation, and could be a peritectoid formation as was previously proposed. Therefore, the sample needs to be homogenized with thermal treatments that favor the formation and stabilization of the compound (CW)

  20. A workplace marked by respect and understanding

    2010-01-01

    Integrity, commitment, professionalism, creativity and diversity: five words that each and every one of us at CERN can identify with, because they represent the core values of this Organization. That’s why they have been chosen as the starting point for our new Code of Conduct, which is being launched this week.  A Code of Conduct describes the basic standards and rules of behaviour that we can expect in the workplace, and it is a statement of the way we see our Organization’s values. CERN’s mission is fundamental research in physics: pushing back the frontiers of human knowledge. In support of that mission, we drive innovation, stimulate international collaboration and inspire a rising generation of scientists. We do all this while respecting the highest ethical standards, and it is this aspect of CERN life that the Code of Conduct describes. CERN’s Code of Conduct has been developed through a collaborative and transparent process to foster shared appre...

  1. Respectful doubts on the new ICRP recommendations

    Diaz de la Cruz, F.

    1992-01-01

    The admiration and deference an International Organization, as ICRP, deserves not only by its altruistic mission but also by the eminent and distinguished scientists who work for it, in some way 'dazzles' to simple students of its theories and, in some way 'force' us to accept, sometimes without any critical, serious and previous meditation, its recommendations. But it is not the bad thing this kind of 'blindness' we have before the almighty ...ICRP dixit..., the worst thing is that non-specialist and non-specialized persons believe as 'dogmas' and 'axioms' the ICRP recommednations and make of them legal dispositions through standards and regulations. Standards an regulations which can frustate an industrial or any other type of peaceful nuclear activity due to the economic or the social reasons derived from ICRP recommendations. The inflexibility (weakened in the arguments but strengthened in the recommendations) of this influent Organism on the 'linearity without threshold' in the dose-effect relationship and the compromises of the International Labor Organization (ILO) with respect ICRP recommedations provole irrational, ilogical and non desirable answers. (author)

  2. [Respecting minors' autonomy in child custody cases].

    Santa Rosa, Bárbara; Corte-Real, Francisco; Vieira, Duarte Nuno

    2013-01-01

    Child custody decisions are among the most difficult for judges to make. The possibility of child abuse allegations or parents' deviant/ psychopathologic behaviours within this context, make the decision further complicated. Based on jurisprudence the listening of children opinion is a way to protect their best interest. In fact children have the right to express an opinion in all matters affecting their life. It should be given proper consideration to children opinion according with his/her age and maturity. Nonetheless custody disputes are emotionally draining issues. Asking the child to express an opinion during a public hearing, most likely in the presence of both parents, its not recommended because this is a potential stressful experience. Child interviews should take place in a proper environment and be set to their age. Medicine and Psychology have an important role in assessing children cognitive, emotional and volitional abilities, which is essential to properly account their opinions according to autonomy degree. This essay analyses the contribution of medico-legal and/or psychological exams to respect the autonomy of the child in cases of regulation of parental responsibilities. The conclusion is the need to establish a symbiotic relationship between the medical and legal perspectives of the (open) concept of child's best interests.

  3. Biocompatible Ni-free Zr-based bulk metallic glasses with high-Zr-content: compositional optimization for potential biomedical applications.

    Hua, Nengbin; Huang, Lu; Chen, Wenzhe; He, Wei; Zhang, Tao

    2014-11-01

    The present study designs and prepares Ni-free Zr60+xTi2.5Al10Fe12.5-xCu10Ag5 (at.%, x=0, 2.5, 5) bulk metallic glasses (BMGs) by copper mold casting for potential biomedical application. The effects of Zr content on the in vitro biocompatibility of the Zr-based BMGs are evaluated by investigating mechanical properties, bio-corrosion behavior, and cellular responses. It is found that increasing the content of Zr is favorable for the mechanical compatibility with a combination of low Young's modulus, large plasticity, and high notch toughness. Electrochemical measurements demonstrate that the Zr-based BMGs are corrosion resistant in a phosphate buffered saline solution. The bio-corrosion resistance of BMGs is improved with the increase in Zr content, which is attributed to the enrichment in Zr and decrease in Al concentration in the surface passive film of alloys. Regular cell responses of mouse MC3T3-E1 cells, including cell adhesion and proliferation, are observed on the Zr-Ti-Al-Fe-Cu-Ag BMGs, which reveals their general biosafety. The high-Zr-based BMGs exhibit a higher cell proliferation activity in comparison with that of pure Zr and Ti-6Al-4V alloy. The effects of Zr content on the in vitro biocompatibility can be used to guide the future design of biocompatible Zr-based BMGs. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Oxide impedance characteristics of the Zr-xNb alloys

    Park, S. Y.; Choi, B. K.; Jung, Y. H.; Jung, Y. H.

    2002-01-01

    To elucidate the correlation between the oxide impedance and corrosion characteristics of the Zr-xNb alloys, the long term corrosion test in high temperature / high pressure aqueous solution and the impedance test in the room temperature sulfate solution were performed. β-quenched plate specimens were heat-treated at 570 .deg. C for 500 hours to get the α+β Nb phase and the at 640 .deg. C for 10 hours to get the α+β Zr phase. The impedance test was conducted in sulfate solution for the initial corrosion test specimen (WG = 30 mg/dm 2 ). To evaluate the impedance date, 4 types of equivalent circuits were constructed by 5 parallel and serial RC elements. By using the equivalent circuits, the thickness of the inner and outer layers were calculated and the electric resistance of each layers were estimated. The corrosion behaviour of Zr-xNb alloys were quite different depending of the annealing condition and Nb-content. The corrosion resistance of the β Nb phase contained high Nb alloys were excellent rather than β Zr phase contained high Nb alloys. The electric resistance of the outer layer of β Zr phase contained high Nb alloy was twice larger than that of β Zr phase contained high Nb alloy, and in the case of outer layer 30% larger. So, the long term corrosion behaviors in high temperature could be estimated well by using the impedance test results

  5. Deuterium absorption property of Al/Zr-V/Mo multifilms

    Wang Haifeng; Peng Shuming; Zhang Xiaohong; Long Xinggui; Yang Benfu

    2005-01-01

    Deuterium absorption property of Al/Zr-V/Mo multifilms was studied experimentally to explore the effect of Al film. There is only one desorption peak at 320 degree C for Al film, two desorption peaks at 220 degree C and 350 degree C for Zr-V film. When the average thickness of Al film is less than 0.6 μm, the desorption property of Al/Zr-V multifilms is just as Zr-V film, when it is more than 0.6 μm, just as Al film. Deuterium absorption by Al/Zr-V multifilms decreases as the thickness of Al film increases until 0.7 μm, then the deuterium absorption no longer changes significantly. The Al film of multifilms cracks on desorbing, so the absorption rate varies as Zr-V film when the thickness of Al film is less than 0.6 μ. When the thickness of Al film is more than 0.6 μm, the deuterium absorption rate of multifilm does not change with the thickness of Al film. (author)

  6. Zr-(Cu,Ag)-Al bulk metallic glasses

    Jiang, Q.K.; Wang, X.D.; Nie, X.P.; Zhang, G.Q.; Ma, H.; Fecht, H.-J.; Bendnarcik, J.; Franz, H.; Liu, Y.G.; Cao, Q.P.; Jiang, J.Z.

    2008-01-01

    In this paper, we report the formation of a series Zr-(Cu,Ag)-Al bulk metallic glasses (BMGs) with diameters at least 20 mm and demonstrate the formation of about 25 g amorphous metallic ingots in a wide Zr-(Cu,Ag)-Al composition range using a conventional arc-melting machine. The origin of high glass-forming ability (GFA) of the Zr-(Cu,Ag)-Al alloy system has been investigated from the structural, thermodynamic and kinetic points of view. The high GFA of the Zr-(Cu,Ag)-Al system is attributed to denser local atomic packing and the smaller difference in Gibbs free energy between amorphous and crystalline phases. The thermal, mechanical and corrosion properties, as well as elastic constants for the newly developed Zr-(Cu,Ag)-Al BMGs, are also presented. These newly developed Ni-free Zr-(Cu,Ag)-Al BMGs exhibit excellent combined properties: strong GFA, high strength, high compressive plasticity, cheap and non-toxic raw materials and biocompatible property, as compared with other BMGs, leading to their potential industrial applications

  7. Densification and Mechanical Properties of ZrN-Nb Composites

    ZHANG Yan

    2018-02-01

    Full Text Available Densification of zirconium nitride (ZrN ceramics was investigated by vacuum hot pressing at temperatures range from 1500℃to 2000℃with Nb as sintering additive. Densification was enhanced with Nb addition. ZrN with 5mol% Nb addition achieved a relative density of 98.5% at 1600℃.XRD and lattice parameter measurements indicated that there were structural differences between samples sintered in different temperatures. It was likely that due to the presence of point defects by changes in stoichiometry, the kinetics of mass transport enhanced. As a result, the relative density of the zirconium nitride (ZrN ceramics have been improved, thus the fully densed ZrN ceramics can be prepared in a relative low temperature. The density, the room-temperature mechanical properties of ZrN ceramics are increased after the addition of Nb. Zirconium nitride (ZrNdoped with Nb sintered at 1600℃ are measured and obtained elasticity modulus of 238 GPa, flexural strength of 463.3 MPa, fracture toughness of 7.0 MPa·m1/2 and hardness of 10.7 GPa.

  8. Electronic structure of ZrX2 (X = Se, Te)

    Shkvarin, A. S.; Merentsov, A. I.; Shkvarina, E. G.; Yarmoshenko, Yu. M.; Píš, I.; Nappini, S.; Titov, A. N.

    2018-03-01

    The electronic structure of the ZrX2 (X = Se, Te) compounds has been studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray absorption spectra, and density of electronic states. It was found that the absorption spectra and valence band spectra are influenced by the chalcogen type. The results of the multiplet calculation of the Zr4+ atom show that the change in the splitting in the crystal field, which is described by the 10Dq parameter, is due to the change in the ratio of covalent and ionic contributions to the chemical bond. The resonance band near the Fermi level in the valence band spectra is observed for ZrTe2 in the Zr 3p-4d resonant excitation mode. The extent of photon energy indicates the charge localization on the Zr atom. Similar resonance band for ZrSe2 is absent; it indicates the presence of a gap at the Fermi level.

  9. Tuning of optical mode magnetic resonance in CoZr/Ru/CoZr synthetic antiferromagnetic trilayers by oblique sputtering

    Wang, Wenqiang; Wang, Fenglong; Cao, Cuimei; Li, Pingping; Yao, Jinli; Jiang, Changjun

    2018-04-01

    CoZr/Ru/CoZr synthetic antiferromagnetic trilayers with strong antiferromagnetic interlayer coupling were fabricated by an oblique sputtering method that induced in-plane uniaxial magnetic anisotropy. A microstrip method using a vector network analyzer was applied to investigate the magnetic resonance modes of the trilayers, including the acoustic modes (AMs) and the optical modes (OMs). At zero magnetic field, the CoZr/Ru/CoZr trilayers showed OMs with resonance frequencies of up to 7.1 GHz. By increasing the applied external magnetic field, the magnetic resonance mode can be tuned to various OMs, mixed modes, and AMs. Additionally, the magnetic resonance mode showed an angular dependence between the magnetization and the microwave field, which showed similar switching of the magnetic modes with variation of the angle. Our results provide important information that will be helpful in the design of multifunctional microwave devices.

  10. Plan of development of ZrC-TRISO coated fuel particle and construction of ZrC coater

    Ueta, Shohei; Ino, Hiroichi; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tobita, Tsutomu [Nuclear Engineering Company, Ltd., Tokai, Ibaraki (Japan); Takahashi, Masashi [Nuclear Fuel Industries, Ltd., Tokyo (Japan)

    2002-11-01

    In order to use coated fuel particle under higher temperature condition, more refractory coating material, which is more refractory than conventional silicon carbide (SiC), should be applied. Zirconium carbide (ZrC) is considered to be one of the promising materials, which is proposed as candidate for VHTR fuel material in GENERATION-IV, because of its intactness under high temperature of around 2000degC and its higher stability against kernel migration (amoeba effect) and fission product corrosion under normal operating condition. In order to develop ZrC coated particle for commercial use, research and development items were extracted based on review of the previous works. Research and development plan was determined. Based on the plan, a new ZrC coater of 100g batch size, which applies bromine process, was constructed. This report describes the review of precious works, extracted research and develop items and plan, and specifications of the ZrC coater. (author)

  11. Modeling and preliminary analysis on the temperature profile of the (TRU-Zr)-Zr dispersion fuel rod for HYPER

    Lee, B. W.; Hwang, W.; Lee, B. S.; Park, W. S.

    2000-01-01

    Either TRU-Zr metal alloy or (TRU-Zr)-Zr dispersion fuel is considered as a blanket fuel for HYPER(Hybrid Power Extraction Reactor). In order to develop the code for dispersion fuel rod performance analysis under steady state condition, the fuel temperature distribution model which is the one of the most important factors in a fuel performance code has been developed in this paper,. This developed model computes the one dimensional radial temperature distribution of a cylindrical fuel rod. The temperature profile results by this model are compared with the temperature distributions of U 3 Si-A1 dispersion fuel and TRU-Zr metal alloy fuel. This model will be installed in performance analysis code for dispersion fuel

  12. The hot deformation behavior and microstructure evolution of HA/Mg-3Zn-0.8Zr composites for biomedical application.

    Liu, Debao; Liu, Yichi; Zhao, Yue; Huang, Y; Chen, Minfang

    2017-08-01

    The hot deformation behavior of nano-sized hydroxylapatite (HA) reinforced Mg-3Zn-0.8Zr composites were performed by means of Gleeble-1500D thermal simulation machine in a temperature range of 523-673K and a strain rate range of 0.001-1s -1 , and the microstructure evolution during hot compression deformation were also investigated. The results show that the flow stress increases increasing strain rates at a constant temperature, and decreases with increasing deforming temperatures at a constant strain rate. Under the same processing conditions, the flow stresses of the 1HA/Mg-3Zn-0.8Zr specimens are higher than those of the Mg-3Zn-0.8Zr alloy specimens, and the difference is getting closer with increasing deformation temperature. The hot deformation behaviors of Mg-3Zn-0.8Zr and 1HA/Mg-3Zn-0.8Zr can be described by constitutive equation of hyperbolic sine function with the hot deformation activation energy being 124.6kJ/mol and 125.3kJ/mol, respectively. Comparing with Mg-3Zn-0.8Zr alloy, the instability region in the process map of 1HA/Mg-3Zn-0.8Zr expanded to a bigger extent at the same conditions. The optimum process conditions of 1HA/Mg-3Zn-0.8Zr composite is concluded as between the temperature window of 573-623K with a strain rate range of 0.001-0.1s -1 . A higher volume fraction and smaller grain size of dynamic recrystallization (DRX) grains was observed in 1HA/Mg-3Zn-0.8Zr specimens after the hot compression deformation compared with Mg-3Zn-0.8Zr alloy, which was ascribed to the presence of the HA particles that play an important role in particle-stimulated nucleation (PSN) mechanism and can effectively hinder the migration of interfaces. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Study of the mechanisms controlling the oxide growth under irradiation: characterization of irradiated zircaloy-4 and Zr-1 Nb-O oxide scales

    Bossis, Ph.; Thomazet, J.; Lefebvre, F.

    2002-01-01

    In PWRs, the Zr-1Nb-O alloy shows a marked enhancement in corrosion resistance in comparison with Zircaloy-4. The aim of this work is to analyze the reasons for these different behaviors and to determine the respective nature of the oxide growth controlling mechanisms under irradiation. Samples taken from Zircaloy-4 irradiated 1, 2, and 4 cycles and Zr-1Nb-O irradiated 1 and 3 cycles have been systematically characterized by optical microscopy, SEM coupled with image analysis, hydride distribution, and XRD. Specific TEM characterizations have been performed on the Zr-1Nb-O samples. A XPS analysis of a nonirradiated sample is also reported. It has been shown that under irradiation the slow oxidation kinetics of the Zr-1Nb-O alloy is associated with very regular metal-oxide interface and oxide layer. On the contrary, the accelerated oxidation kinetics of Zircaloy-4 is associated with highly perturbed metal-oxide interface and oxide layer. On both irradiated alloys, cracks are observed to initiate preferentially above the delayed parts of the oxidation front. Hydrogen intake during water oxidation in PWR environment is found to be much lower on the Zr-1Nb-O alloy than on Zircaloy-4. More β-ZrO 2 is found on the oxide layer formed on Zircaloy-4 than on Zr-1NbO after oxidation in PWR. Classical irradiation-induced microstructural evolution is observed in the Zr-1Nb-O metallic alloy after 3 cycles, i.e., a fine β-Nb precipitation. β-Nb precipitates are observed to undergo a delayed oxidation associated with a crystalline to amorphous transformation. After water oxidation in autoclave, a pronounced Nb segregation is detected on the oxide surface of a Zr-1Nb-O sample. These results suggest that the oxidation kinetics of Zircaloy-4 is controlled essentially by oxygen diffusion through the inner barrier layer, which is significantly accelerated under irradiation. The oxidation kinetics of Zr-1Nb-O is controlled by both oxygen diffusion through the inner barrier and by

  14. Experimental investigation shell model excitations of 89Zr up to high spin and its comparison with 88,90Zr

    Saha, S.; Palit, R.; Sethi, J.

    2012-01-01

    The excited states of nuclei near N=50 closed shell provide suitable laboratory for testing the interactions of shell model states, possible presence of high spin isomers and help in understanding the shape transition as the higher orbitals are occupied. In particular, the structure of N = 49 isotones (and Z =32 to 46) with one hole in N=50 shell gap have been investigated using different reactions. Interestingly, the high spin states in these isotones have contribution from particle excitations across the respective proton and neutron shell gaps and provide suitable testing ground for the prediction of shell model interactions describing theses excitations across the shell gap. In the literature, extensive study of the high spin states of heavier N = 49 isotones starting with 91 Mo up to 95 Pd are available. Limited information existed on the high spin states of lighter isotones. Therefore, the motivation of the present work is to extend the high spin structure of 89 Zr and to characterize the structure of these levels through comparison with the large scale shell model calculations based on two new residual interactions in f 5/2 pg 9/2 model space

  15. Microstructural characterization of LaB6-ZrB2 eutectic composites

    Wang Shengchang; Wei, W.J.; Zhang Litong

    2003-01-01

    Detail microstructure of LaB 6 -ZrB 2 composites has been characterized by TEM and HRTEM. The directionally solidified ZrB 2 fibers in LaB 6 matrix near LaB 6 -ZrB 2 eutectics present at least three growing relationship systems. In addition to previous report of [001]LaB 6 / [0001]ZrB 2 relationship, [0 anti 11]LaB 6 / [0001]ZrB 2 and [1 anti 20]LaB 6 / [0001]ZrB 2 . were identified. Different with [001]LaB 6 / [0001]ZrB 2 system, the interfaces of [0 anti 11]LaB 6 / [0001]ZrB 2 and [1 anti 20]LaB 6 / [0001]ZrB 2 . show non-coherent and clean interfaces. There is neither glassy phase nor reaction products found at the interfaces (orig.)

  16. Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

    Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun

    2017-01-01

    The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr 7 Ni 10 , ZrNi, ZrNi 5 , Zr 14 Cu 51 , and Zr 2 Cu 9 , show a remarkable ternary solubility. A new ternary compound named τ 3 (Zr 31.1-30.7 . Cu 28.5-40.3 Ni 40.4-29.0 ) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

  17. Enthalpy increment measurements of Sr3Zr2O7(s) and Sr4Zr3O10(s)

    Banerjee, A.; Dash, S.; Prasad, R.; Venugopal, V.

    1998-01-01

    Enthalpy increment measurements on Sr 3 Zr 2 O 7 (s) and Sr 4 Zr 3 O 10 (s) were carried out using a Calvet micro-calorimeter. The enthalpy increment values were least squares analyzed with the constraints that H 0 (T)-H 0 (298.15 K) at 298.15 K equals to zero and C p 0 (298.15 K) equals to the estimated value. The dependence of enthalpy increment with temperature is given. (orig.)

  18. A First-Principles Study on the Vibrational and Electronic Properties of Zr-C MXenes

    Wang, Chang-Ying; Guo, Yong-Liang; Zhao, Yuan-Yuan; Zeng, Guang-Li; Zhang, Wei; Ren, Cui-Lan; Han, Han; Huai, Ping

    2018-03-01

    Within the framework of density functional theory calculations, the structural, vibrational, and electronic properties of Zr n C n - 1 (n = 2, 3, and 4) and their functionalized MXenes have been investigated. We find that the most stable configurations for Zr-C MXene are the ones that the terminal groups F, O, and OH locate on the common hollow site of the superficial Zr layer and its adjacent C layer. F and OH-terminated Zr 3 C 2 and Zr 4 C 3 have small imaginary acoustic phonon branches around Γ point while the others have no negative phonon modes. The pristine MXenes (Zr 2 C, Zr 3 C 2 and Zr 4 C 3 ) are all metallic with large DOS contributed by the Zr atom at the Fermi energy. When functionalized by F, O and OH, new hybridization states appear and the DOS at the Fermi level are reduced. Moreover, we find that their metallic characteristic increases with an increase in n. For (Zr n C n - 1 )O 2, Zr 2 CO 2 is a semiconductor, Zr 3C2O2 is a semimetal, and Zr 4 C 3O2 becomes a metal. Supported by the National Natural Science Foundation of China under Grant Nos. 11605273, 21571185, U1404111, 11504089, 21501189, 21676291, the Shanghai Municipal Science and Technology Commission 16ZR1443100, the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA02040104)

  19. Corrosion behavior of Zr-x(Nb, Sn and Cu) binary alloys

    Kim, M. H.; Lee, M. H.; Park, S. Y.; Jung, Y. H.; We, M. Y.

    1999-01-01

    For the development of advanced zirconium alloys for nuclear fuel cladding, the corrosion behaviors of zirconium binary alloys were studied on the Zr-xNb, Zr-xSn, and Zr-xCu alloys. The corrosion test were performed in water at 360 deg C, steam at 400 deg C and LiOH at 360 deg C for 45 days. The corrosion behaviors of Zr-xNb was similar to that of Zr-xCu alloys. However, the corrosion behavior of Zr-xSn was different from Zr-xNb and Zr-xCu. The weight gain of Zr-xNb and Zr-xCu was increased with addition of alloying elements. When Sn is added to Zr matrix in range below the solubility limit, the corrosion resistance decrease with increasing Sn-content, while in the range over solubility limit, Sn has an adverse effect on the corrosion resistance. Especially, Zr-xSn alloys showed higher corrosion resistance than Zr-xNb and Zr-xCu alloys in LiOH solution

  20. Development of modified route for fabrication of Zr-2.5Nb alloy pressure tubes

    Saibaba, N.; Hemantha Rao, G.V.S.; Phani Babu, C.; Jha, S.K.; Ganesha, G.N.; Ramana Rao, S.V.; Kumar Vaibhaw; Dey, G.K.; Srivastava, D.; Neogy, S.; Mani Krishna, K.V.

    2013-01-01

    Different fabrication trials involving the variation in three important manufacturing stages of Zr-2.5%Nb pressure tube were partially undetaken. The variations were with respect of mode of breaking the cast structure of the ingot (forging vs extrution), ratio of hot extrusion and number of stages of subsequent cold work to produce the finished tube. It was observed that forging process resulted in superior performance in breaking the cast structure. Higher extrusion ratios resulted in more favorable texture and microstrucutre. Continuity of the beta phase in the final microstructure was observed to be more in case of route involving single cold work subsequent to hot extrusion. (author)

  1. Respect-Due and Respect-Earned: Negotiating Student-Teacher Relationships

    Goodman, Joan F.

    2009-01-01

    Respect is a cardinal virtue in schools and foundational to our common ethical beliefs, yet its meaning is muddled. For philosophers Kant, Mill, and Rawls, whose influential theories span three centuries, respect includes appreciation of universal human dignity, equality, and autonomy. In their view children, possessors of human dignity, but…

  2. "We Want Respect": Adults with Intellectual and Developmental Disabilities Address Respect in Research

    McDonald, Katherine Elizabeth

    2012-01-01

    Respect is central to ethical guidelines for research. The scientific community has long debated, and at times disagreed on, how to demonstrate respect in research with adults with intellectual and developmental disabilities. To illuminate the voices of those most affected, the author studies the views of adults with intellectual and developmental…

  3. Research as a Respectful Practice: An Exploration of the Practice of Respect in Qualitative Research

    O'Grady, Emmanuel

    2016-01-01

    This article explores the practice of respect within qualitative research methods. As interpersonal respect plays a significant role in the esteem felt within a relationship, it can also serve to cultivate trust between researchers and their participants in a research study. This article details the findings of a research study examining respect…

  4. Imaging brain activity during seizures in freely behaving rats using a miniature multi-modal imaging system.

    Sigal, Iliya; Koletar, Margaret M; Ringuette, Dene; Gad, Raanan; Jeffrey, Melanie; Carlen, Peter L; Stefanovic, Bojana; Levi, Ofer

    2016-09-01

    We report on a miniature label-free imaging system for monitoring brain blood flow and blood oxygenation changes in awake, freely behaving rats. The device, weighing 15 grams, enables imaging in a ∼ 2 × 2 mm field of view with 4.4 μm lateral resolution and 1 - 8 Hz temporal sampling rate. The imaging is performed through a chronically-implanted cranial window that remains optically clear between 2 to > 6 weeks after the craniotomy. This imaging method is well suited for longitudinal studies of chronic models of brain diseases and disorders. In this work, it is applied to monitoring neurovascular coupling during drug-induced absence-like seizures 6 weeks following the craniotomy.

  5. Robust, highly customizable, and economical multi-channel electrode for chronic multi-unit recording in behaving animals.

    Tateyama, Yukina; Oyama, Kei; Shiraishi, Masaru; Iijima, Toshio; Tsutsui, Ken-Ichiro

    2017-12-01

    Multi-unit recording has been one of the most widely used techniques to investigate the correlation between multiple neuronal activities and behavior. However, a common problem of currently used multi-channel electrodes is their physical weakness. In this study, we developed a novel multi-channel electrode with sufficient physical strength to penetrate a thickened dura mater. This electrode consists of low-cost materials and is easily fabricated, and it enables recording without removing dura mater, thereby reducing the risk of inflammation, infection, or brain herniation. The low-cost multi-channel electrode developed in this study would be a useful tool for chronic recording in behaving animals. Copyright © 2017. Published by Elsevier B.V.

  6. Synchronized Activity in The Main and Accessory Olfactory Bulbs and Vomeronasal Amygdala Elicited by Chemical Signals in Freely Behaving Mice.

    Pardo-Bellver, Cecília; Martínez-Bellver, Sergio; Martínez-García, Fernando; Lanuza, Enrique; Teruel-Martí, Vicent

    2017-08-30

    Chemosensory processing in mammals involves the olfactory and vomeronasal systems, but how the activity of both circuits is integrated is unknown. In our study, we recorded the electrophysiological activity in the olfactory bulbs and the vomeronasal amygdala in freely behaving mice exploring a battery of neutral and conspecific stimuli. The exploration of stimuli, including a neutral stimulus, induced synchronic activity in the olfactory bulbs characterized by a dominant theta rhythmicity, with specific theta-gamma coupling, distinguishing between vomeronasal and olfactory structures. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in the nasal cavity and the vomeronasal pumping. In the amygdala, male stimuli are preferentially processed in the medial nucleus, whereas female cues induced a differential response in the posteromedial cortical amygdala. Thus, particular theta-gamma patterns in the olfactory network modulates the integration of chemosensory information in the amygdala, allowing the selection of an appropriate behaviour.

  7. Moessbauer spectroscopy of the Zr-rich region in Zr-Nb-Fe alloys with low Nb content

    Ramos, C.; Saragovi, C.; Granovsky, M.; Arias, D.

    1999-01-01

    Intermetallic phases and solid solutions in the Zr-rich region of the Zr-Nb-Fe system with low Nb content are studied by Moessbauer spectroscopy complemented with X-ray diffraction, optical and scanning electron microscopy and electron microprobe analysis. The phases found in each sample were those expected from the corresponding binary Zr-Fe system. Furthermore, one of the samples showed a ternary cubic Ti 2 Ni type phase with a similar stoichiometry to the tetragonal Zr 2 Fe compound. Moessbauer parameters were suggested to this phase (IS: - 0.12 mm/s, QS: 0.30 mm/s), to the bcc Zr(β) phase (IS: (-0.11 α 0.01) mm/s, QS: (0.23 α 0.02) mm/s), and to the hcp Zr(β T ) phase (IS: (-0.24 α 0.02) mm/s, QS: (0.45 α 0.02) mm/s)

  8. Moessbauer spectroscopy of the Zr-rich region in Zr-Nb-Fe alloys with low Nb content

    Ramos, C. [Universidad de Buenos, Facultad de Ciencias Exactas y Naturales (Argentina); Saragovi, C. [Departamento de Fisica, Comision Nacional de Energia Atomica (Argentina); Granovsky, M.; Arias, D. [Departamento de Materiales, Comision Nacional de Energia Atomica (Argentina)

    1999-11-15

    Intermetallic phases and solid solutions in the Zr-rich region of the Zr-Nb-Fe system with low Nb content are studied by Moessbauer spectroscopy complemented with X-ray diffraction, optical and scanning electron microscopy and electron microprobe analysis. The phases found in each sample were those expected from the corresponding binary Zr-Fe system. Furthermore, one of the samples showed a ternary cubic Ti{sub 2}Ni type phase with a similar stoichiometry to the tetragonal Zr{sub 2}Fe compound. Moessbauer parameters were suggested to this phase (IS: - 0.12 mm/s, QS: 0.30 mm/s), to the bcc Zr({beta}) phase (IS: (-0.11 {alpha} 0.01) mm/s, QS: (0.23 {alpha} 0.02) mm/s), and to the hcp Zr({beta}{sup T}) phase (IS: (-0.24 {alpha} 0.02) mm/s, QS: (0.45 {alpha} 0.02) mm/s)

  9. The factors affecting the 95Nb/95Zr and 140La/95Zr-cooling time correlations

    Haddad, Kh

    2005-03-01

    The factors affecting the 95 Nb/ 95 Zr and 140 La/ 95 Zr-cooling time correlations were studied by analysing the gamma scanning results of the IRT fuel assemblies. the results showed that, these ratios are stable along the fuel assembly regardless of the position of the measured section. This allow to limit gamma scanning of the whole assembly on the measurement of the central section. The effects of irradiation history and conditions, burnup, control rods on the 95 Nb/ 95 Zr and 140 La/ 95 Zr-cooling time correlations were studied. The results showed the following: the identical irradiation history and conditions during the last irradiation, whose period is comparable with half lives of the used fission products, is fundamental condition for fission product ratio-cooling time correlation. The background resulting from burnup cause high systematic error in the measured results and it does not cause arbitrary error; whereas control rods cause high arbitrary error. The 95 Nb/ 95 Zr-cooling time correlation is more sensitive than the 140 La/ 95 Zr-cooling time correlation. (author)

  10. The influence of Zr substitution for Nb on the corrosion behaviors of the Ni-Nb-Zr bulk metallic glasses

    Li, DengKe; Zhu, ZhengWang; Zhang, HaiFeng; Wang, AiMin; Hu, ZhuangQi

    2012-12-01

    The influence of Zr content on corrosion behaviors of the Ni61.5Nb38.5- x Zr x ( x=1, 3, 5, 7, 9 at.%) bulk metallic glasses (BMGs) in 1 M HCl aqueous solution was investigated by potentiodynamic polarization measurements and X-ray photo-electron spectroscopy (XPS). It was found that these BMG alloys possess superior corrosion resistance, that is, with large passive region of about 1.5 V and low passive current density (as low as 0.05 Am-2 for Ni61.5Nb31.5Zr7). XPS analysis indicates that the high corrosion resistance is attributed to the formation of Nb- and Zr-enriched surface films formed in the aggressive acid solution. The Zr substitution for Nb effectively reduces the Ni content, particularly the metallic state Ni content in the surface films, which depresses the electrical conduction of the surface films and reduces the passive current density, thus leading to the enhancement of the corrosion resistance of these Ni-Nb-Zr BMGs. These alloys may potentially be useful for engineering applications.

  11. Corrosion of electron-irradiated Zr-2.5Nb and Zircaloy-2

    Woo, O.-T.; McDougall, G.M.; Hutcheon, R.M.; Urbanic, V.F.; Griffiths, M.; Coleman, C.E

    2000-07-01

    We used 10-MeV electrons to rapidly produce radiation damage in zirconium alloys, investigated whether electrons produced the same microstructural changes as neutrons, then performed post-irradiation corrosion tests to determine whether electron-irradiated materials displayed similar corrosion behavior to neutron-irradiated materials. Two irradiations were completed using 10-MeV electrons with the beam normal to thin disks of material of 4 diameter slightly larger than the beam. The beam distribution. and disk cooling were designed to produce radial temperature and dose distributions having maxima at the disk center. A high-temperature irradiation was performed on annealed Zr-2.5Nb disks, achieving a central dose of 1.3 dpa and at a central temperature of {approx}450 deg C. After irradiation, the samples contained needle-like {beta}-Nb precipitates in the {alpha}-Zr matrix similar to those produced by neutrons. A low-temperature irradiation was performed on half-moon disks of Zr-2.5Nb and Zircaloy-2 pressure tube materials at 310 deg C central temperature and 1.3-dpa central dose. Dislocation loops were observed, again similar to those produced in neutron-irradiated materials. Some of the high-temperature electron-irradiated disks were exposed to 300 deg C moist air (saturated with D{sub 2}O), and in separate tests, high- and low-temperature irradiated disks were corroded in 300 deg C D{sub 2}0 (11.0 pD at room temperature) in an autoclave. Measurements of oxide thickness by Fourier Transform Infrared Reflectance (FTIR) spectroscopy showed that electron irradiation reduced the corrosion rate of Zr-2.5Nb compared with that of unirradiated material, as observed for neutron irradiation. For exposures to moist air and to D{sub 2}O, the theoretical deuterium uptakes for the electron-irradiated materials were, respectively, about 4 times and 1.5 to 2 times those for the unirradiated materials. This is also in good agreement with results for neutron-irradiated pressure

  12. Corrosion of electron-irradiated Zr-2.5Nb and Zircaloy-2

    Woo, O.-T.; McDougall, G.M.; Hutcheon, R.M.; Urbanic, V.F.; Griffiths, M.; Coleman, C.E.

    2000-01-01

    We used 10-MeV electrons to rapidly produce radiation damage in zirconium alloys, investigated whether electrons produced the same microstructural changes as neutrons, then performed post-irradiation corrosion tests to determine whether electron-irradiated materials displayed similar corrosion behavior to neutron-irradiated materials. Two irradiations were completed using 10-MeV electrons with the beam normal to thin disks of material of 4 diameter slightly larger than the beam. The beam distribution. and disk cooling were designed to produce radial temperature and dose distributions having maxima at the disk center. A high-temperature irradiation was performed on annealed Zr-2.5Nb disks, achieving a central dose of 1.3 dpa and at a central temperature of ∼450 deg C. After irradiation, the samples contained needle-like β-Nb precipitates in the α-Zr matrix similar to those produced by neutrons. A low-temperature irradiation was performed on half-moon disks of Zr-2.5Nb and Zircaloy-2 pressure tube materials at 310 deg C central temperature and 1.3-dpa central dose. Dislocation loops were observed, again similar to those produced in neutron-irradiated materials. Some of the high-temperature electron-irradiated disks were exposed to 300 deg C moist air (saturated with D 2 O), and in separate tests, high- and low-temperature irradiated disks were corroded in 300 deg C D 2 0 (11.0 pD at room temperature) in an autoclave. Measurements of oxide thickness by Fourier Transform Infrared Reflectance (FTIR) spectroscopy showed that electron irradiation reduced the corrosion rate of Zr-2.5Nb compared with that of unirradiated material, as observed for neutron irradiation. For exposures to moist air and to D 2 O, the theoretical deuterium uptakes for the electron-irradiated materials were, respectively, about 4 times and 1.5 to 2 times those for the unirradiated materials. This is also in good agreement with results for neutron-irradiated pressure tube materials. Thus, 10-Me

  13. Enhanced performance of P(VDF-HFP)-based composite polymer electrolytes doped with organic-inorganic hybrid particles PMMA-ZrO2 for lithium ion batteries

    Xiao, Wei; Wang, Zhiyan; Zhang, Yan; Fang, Rui; Yuan, Zun; Miao, Chang; Yan, Xuemin; Jiang, Yu

    2018-04-01

    To improve the ionic conductivity as well as enhance the mechanical strength of the gel polymer electrolyte, poly(vinylidene fluoride-hexafluoroprolene) (P(VDF-HFP))-based composite polymer electrolyte (CPE) membranes doped with the organic-inorganic hybrid particles poly(methyl methacrylate) -ZrO2 (PMMA-ZrO2) are prepared by phase inversion method, in which PMMA is successfully grafted onto the surface of the homemade nano-ZrO2 particles via in situ polymerization confirmed by FT-IR. XRD and DSC patterns show adding PMMA-ZrO2 particles into P(VDF-HFP) can significantly decrease the crystallinity of the CPE membrane. The CPE membrane doped with 5 wt % PMMA-ZrO2 particles can not only present a homogeneous surface with abundant interconnected micro-pores, but maintain its initial shape after thermal exposure at 160 °C for 1 h, in which the ionic conductivity and lithium ion transference number at room temperature can reach to 3.59 × 10-3 S cm-1 and 0.41, respectively. The fitting results of the EIS plots indicate the doped PMMA-ZrO2 particles can significantly lower the interface resistance and promote lithium ions diffusion rate. The Li/CPE-sPZ/LiCoO2 and Li/CPE-sPZ/Graphite coin cells can deliver excellent rate and cycling performance. Those results suggest the P(VDF-HFP)-based CPE doped with 5 wt % PMMA-ZrO2 particles can become an exciting potential candidate as polymer electrolyte for the lithium ion battery.

  14. Synergistic effect of PANI-ZrO2 composite as antibacterial, anti-corrosion, and phosphate adsorbent material: synthesis, characterization and applications.

    Masim, Frances Camille P; Tsai, Cheng-Hsien; Lin, Yi-Feng; Fu, Ming-Lai; Liu, Minghua; Kang, Fei; Wang, Ya-Fen

    2017-11-03

    The increasing number of bacteria-related problems and presence of trace amounts of phosphate in treated wastewater effluents have become a growing concern in environmental research. The use of antibacterial agents and phosphate adsorbents for the treatment of wastewater effluents is of great importance. In this study, the potential applications of a synthesized polyaniline (PANI)-zirconium dioxide (ZrO 2 ) composite as an antibacterial, phosphate adsorbent and anti-corrosion material were systematically investigated. The results of an antibacterial test reveal an effective area of inhibition of 14 and 18 mm for the Escherichia coli and Staphylococcus aureus bacterial strains, respectively. The antibacterial efficiency of the PANI-ZrO 2 composite is twice that of commercial ZrO 2 . In particular, the introduction of PANI increased the specific surface area and roughness of the composite material, which was beneficial to increase the contact area with bacterial and phosphate. The experimental results demonstrated that phosphate adsorption studies using 200 mg P/L phosphate solution showed a significant phosphate removal efficiency of 64.4%, and the maximum adsorption capacity of phosphate on the solid surface of PANI-ZrO 2 is 32.4 mg P/g. Furthermore, PANI-ZrO 2 coated on iron substrate was tested for anti-corrosion studies by a natural salt spray test (7.5% NaCl), which resulted in the formation of no rust. To the best of our knowledge, no works have been reported on the synergistic effects of the PANI-ZrO 2 composite as an antibacterial, anti-corrosion, and phosphate adsorbent material. PANI-ZrO 2 composite is expected to be a promising comprehensive treatment method for water filters in the aquaculture industry and for use in water purification applications.

  15. Crystallization behavior and the thermal properties of Zr63Al7.5Cu17.5Ni10B2 bulk amorphous alloy

    Jang, J.S.C.; Chang, L.J.; Jiang, Y.T.; Wong, P.W.

    2003-01-01

    The ribbons of amorphous Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys with 0.1 mm thickness were prepared by melt spinning method. The thermal properties and micro structural development during the annealing of amorphous alloy have been investigated by a combination of differential thermal analysis, differential scanning calorimetry, high-temperature optical microscope, X-ray diffractometry and TEM. The glass transition temperature for the Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys are measured about 645 K (372 C). This alloy also obtains a large temperature interval ΔT x about 63 K. Meanwhile, the calculated T rg for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy presents the value of 0.57. The activation energy of crystallization for the alloy Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 was about 370± 10 kJ/mole as determined by the Kissinger and Avrami plot, respectively. These values are about 20% higher than the activation energy of crystallization for the Zr 65 Al 7.5 Cu 17.5 Ni 10 alloy (314 kJ/mol.). This implies that the boron additions exhibit the effect of improving the thermal stability for the Zr-based alloy. The average value of the Avrami exponent n were calculated to be 1.75±0.15 for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy. This indicates that this alloy presents a crystallization process with decreasing nucleation rate. (orig.)

  16. Phase transition temperature in the Zr-rich corner of Zr-Nb-Sn-Fe alloys

    Canay, M.; Danón, C. A.; Arias, D.

    2000-08-01

    The influence of small composition changes on the phase transformation temperature of Zr-1Nb-1Sn-0.2(0.7)Fe alloys was studied in the present work, by electrical resistivity measurements and metallographic techniques. For the alloy with 0.2 at.% Fe we have determined Tα↔α+β=741°C and Tα+β↔β=973°C, and for the 0.7 at.% Fe the transformation temperatures were T α↔α+β=712°C and T α+β↔β=961°C. We have verified that the addition of Sn stabilized the β phase.

  17. Microstructure and thermal stability of Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coatings

    Meng, Jian-ping; Guo, Rui-rui; Li, Hu; Zhao, Lu-ming; Liu, Xiao-peng; Li, Zhou

    2018-05-01

    Solar selective absorbing coatings play a valuable role in photo-thermal conversion for high efficiency concentrating solar power systems (CSP). In this paper, a novel Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coating was successfully deposited by ion beam assisted deposition. The optical properties, microstructure and element distribution in depth were investigated by spectroscopic ellipsometry, UV-vis-NIR spectrophotometer, transmission electron microscope (TEM) and Auger electron spectroscopy (AES), respectively. A high absorptance of 0.953 and a low thermal emittance of 0.079 at 400 °C are obtained by the integral computation according to the whole reflectance from 300 nm to 28,800 nm. After annealing treatment at 400 °C (in vacuum) for 192 h, the deposited coating exhibits the high thermal stability. Whereas, the photothermal conversion efficiency decreases from 12.10 to 6.86 due to the emittance increase after annealing at 600 °C for 192 h. Meanwhile, the nitrogen atom in the Zr0.3Al0.7N sub-layer diffuses toward the adjacent sub-layer due to the spinodal decomposition of metastable c-ZrAlN and the phase transition from c-AlN to h-AlN, which leads to the composition of the Zr0.3Al0.7N sub-layer deviates the initial design. This phenomenon has a guide effect for the thermal-stability improvement of cermet coatings. Additionally, a serious diffusion between copper and silicon substrate also contributes to the emittance increase.

  18. The role of the intrinsic cholinergic system of the striatum: What have we learned from TAN recordings in behaving animals?

    Apicella, Paul

    2017-09-30

    Cholinergic interneurons provide rich local innervation of the striatum and play an important role in controlling behavior, as evidenced by the variety of movement and psychiatric disorders linked to disrupted striatal cholinergic transmission. Much progress has been made in recent years regarding our understanding of how these interneurons contribute to the processing of information in the striatum. In particular, investigation of the activity of presumed striatal cholinergic interneurons, identified as tonically active neurons or TANs in behaving animals, has pointed to their role in the signaling and learning of the motivational relevance of environmental stimuli. Although the bulk of this work has been conducted in monkeys, several studies have also been carried out in behaving rats, but information remains rather disparate across studies and it is still questionable whether rodent TANs correspond to TANs described in monkeys. Consequently, our current understanding of the function of cholinergic transmission in the striatum is challenged by the rapidly growing, but often confusing literature on the relationship between TAN activity and specific behaviors. As regards the precise nature of the information conveyed by the cholinergic TANs, a recent influential view emphasized that these local circuit neurons may play a special role in the processing of contextual information that is important for reinforcement learning and selection of appropriate actions. This review provides a summary of recent progress in TAN physiology from which it is proposed that striatal cholinergic interneurons are crucial elements for flexible switching of behaviors under changing environmental conditions. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Real-time supervisor system based on trinary logic to control experiments with behaving animals and humans.

    Kutz, D F; Marzocchi, N; Fattori, P; Cavalcanti, S; Galletti, C

    2005-06-01

    A new method is presented based on trinary logic able to check the state of different control variables and synchronously record the physiological and behavioral data of behaving animals and humans. The basic information structure of the method is a time interval of defined maximum duration, called time slice, during which the supervisor system periodically checks the status of a specific subset of input channels. An experimental condition is a sequence of time slices subsequently executed according to the final status of the previous time slice. The proposed method implements in its data structure the possibility to branch like an if-else cascade and the possibility to repeat parts of it recursively like the while-loop. Therefore its data structure contains the most basic control structures of programming languages. The method was implemented using a real-time version of LabVIEW programming environment to program and control our experimental setup. Using this supervision system, we synchronously record four analog data channels at 500 Hz (including eye movements) and the time stamps of up to six neurons at 100 kHz. The system reacts with a resolution within 1 ms to changes of state of digital input channels. The system is set to react to changes in eye position with a resolution within 4 ms. The time slices, experimental conditions, and data are handled by relational databases. This facilitates the construction of new experimental conditions and data analysis. The proposed implementation allows continuous recording without an inter-trial gap for data storage or task management. The implementation can be used to drive electrophysiological experiments of behaving animals and psychophysical studies with human subjects.

  20. Mechanical and dynamical behaviors of ZrSi and ZrSi{sub 2} bulk metallic glasses: A molecular dynamics study

    Ju, Shin-Pon, E-mail: jushin-pon@mail.nsysu.edu.tw [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China); Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Wu, Tsang-Yu; Liu, Shih-Hao [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan (China)

    2015-03-14

    The mechanical and dynamical properties of ZrSi and ZrSi{sub 2} bulk metallic glasses (BMGs) have been investigated by molecular dynamics simulation. The Honeycutt-Anderson (HA) index analysis indicates that the major indexes in ZrSi and ZrSi{sub 2} bulk metallic glasses are 1551, 1541, and 1431, which refers to the liquid structure. For uniaxial tension, the results show that the ZrSi and ZrSi{sub 2} BMGs are more ductile than their crystal counterparts. The evolution of the distribution of atomic local shear strain clearly shows the initialization of shear transformation zones (STZs), the extension of STZs, and the formation of shear bands along a direction 45° from the tensile direction when the tensile strain gradually increases. The self-diffusion coefficients of ZrSi and ZrSi{sub 2} BMGs at temperatures near their melting points were calculated by the Einstein equation according to the slopes of the MSD profiles at the long-time limit. Because the HA fraction summation of icosahedral-like structures of ZrSi BMG is higher than that of ZrSi{sub 2} BMG, and these local structures are more dense, the self-diffusion coefficients of the total, Zr, and Si atoms of ZrSi{sub 2} BMG are larger than those of ZrSi BMG. This can be attributed to the cage effect, where a denser local structure has a higher possibility of atoms jumping back to form a backflow and then suppress atomic diffusivity. For ZrSi{sub 2} BMG, the self-diffusion coefficient of Si increases with temperature more significantly than does that of Zr, because more open packing rhombohedra structures are formed by the Si-Si pair.